Article

Can We Predict the Ultimate Lumbar Curve in Adolescent Idiopathic Scoliosis Patients Undergoing a Selective Fusion with Undercorrection of the Thoracic Curve?

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Abstract

Retrospective review of anterior and posterior fusions for treatment of adolescent idiopathic thoracic scoliosis. To delineate the best factors determining final lumbar curve magnitude in patients with adolescent idiopathic scoliosis undergoing a selective thoracic anterior or posterior spinal fusion at or proximal to the first lumbar vertebra. Although spontaneous lumbar curve correction occurs consistently following a selective thoracic anterior or posterior spinal fusion, the degree of correction is somewhat unpredictable. One hundred consecutive patients with major thoracic-compensatory lumbar adolescent idiopathic scoliosis treated by a single surgeon with either selective posterior spinal fusion (n = 44) or anterior spinal fusion (n = 56) of the main thoracic region with an unfused lumbar spine with a lumbar B modifier (lumbar apex touching the center sacral vertical line) or lumbar C modifier (lumbar apex completely lateral to the center sacral vertical line) were retrospectively reviewed. Those patients who maintained excellent postoperative coronal balance, with spontaneous lumbar curve correction, had their thoracic Cobb corrected intraoperatively to a measurement very close to but not more than that of the preoperative thoracic push-prone Cobb. Stepwise multiple linear regression analysis was used to develop a formula to help predict lumbar response in those patients undergoing selective thoracic fusion. This is represented in the following formula: Final lumbar Cobb = 14.4 + 3.06 (lumbar modifier; 0 = B, 1 = C) + 0.30 (preoperative standing lumbar Cobb) - 0.18 (preoperative supine lower Cobb) + 0.81(preoperative push/prone lumbar Cobb) - 0.15(preoperative standing thoracic Cobb) - 0.16(% thoracic Cobb change from preoperative to immediate postoperative). Final model R2 = 0.72. Of the preoperative measurements examined, the preoperative push-prone is the best preoperative flexibility radiograph to predict the final lumbar curve measurement and, along with other factors, can be used to formulate a model that will help the treating surgeon more confidently predict the final lumbar curve response in patients undergoing a selective thoracic fusion.

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... Selective thoracic fusion (STF) has been the gold standard for treating primary thoracic and compensatory lumbar curves in adolescent idiopathic scoliosis (AIS), in which both the thoracic and lumbar curves cross midline, and the lumbar curve is smaller and more flexible than the thoracic curve, since Moe had advocated its concept [1,2]. For this curve pattern, STF induces spontaneous lumbar curve correction and preserves more mobile lumbar segments than does fusing both the thoracic and lumbar curves [3][4][5][6][7][8]. However, postoperative coronal imbalance is a significant problem after STF [7,[9][10][11], which may result in poor surgical outcomes with re-operation. ...
... Thus, the postoperative behavior of coronal balance is a major concern in the surgical outcomes for primary thoracic and compensatory lumbar curves in AIS. Causative factors reported for postoperative coronal decompensation include excessive correction of the thoracic curve, improper selection of the lowest instrumented vertebra (LIV), pre-existing coronal decompensation, and inappropriate curve identification [7][8][9][10][11]13]; however, many of previous studies on postoperative behavior of coronal balance after STF are based on various surgical approaches including anterior approach and/or posterior approach with pedicle screw (PS), hook or hybrid constructs [3,4,6,10,13], and those with PS construct are scant. Apparently, surgical procedures and corrective maneuvers would influence the postoperative course of unfused lumbar curve and coronal balance. ...
... The mean age and Risser grade at the time of surgery were 15.1 ± 2.7 (11-22) years old and 3.4 ± 1.4 (1)(2)(3)(4)(5), respectively. The mean follow-up period was 3.1 (2-7.3) ...
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Background Postoperative coronal imbalance is a significant problem after selective thoracic fusion for primary thoracic and compensatory lumbar curves in adolescent idiopathic scoliosis (AIS). However, longitudinal studies on postoperative behavior of coronal balance are lacking. This multicenter retrospective study was conducted to analyze factors related to onset and remodeling of postoperative coronal imbalance after posterior thoracic fusion for Lenke 1C and 2C AIS. Methods Twenty-one Lenke 1C or 2C AIS patients, who underwent posterior thoracic fusion ending at L3 or above, were included with a minimum 2-year follow-up. The mean patients’ age was 15.1 years at the time of surgery. Radiographic measurements were performed on Cobb angles of the main thoracic (MT) and thoracolumbar/lumbar (TLL) curves and coronal balance. Factors related to the onset of immediately postoperative coronal decompensation (IPCD) and postoperative coronal balance remodeling (PCBR), defined as an improvement of coronal balance during postoperative follow-up, were investigated using comparative and correlation analyses. Results Mean Cobb angles for the MT and TLL curves were 57.3° and 42.3° preoperatively and were corrected to 22.8° and 22.5° at final follow-up, respectively. Mean preoperative coronal balance of −3.8 mm got worse to −21.2 mm postoperatively, and regained to −12.0 mm at final follow-up. Coronal decompensation was observed in two patients preoperatively, in ten patients immediately postoperatively, and in three patients at final follow-up. The preoperative coronal balance and lowest instrumented vertebra (LIV) selection relative to stable vertebra (SV) were significantly different between patients with IPCD and those without. PCBR had significantly negative correlation with immediately postoperative coronal balance. Conclusions IPCD after posterior thoracic fusion for Lenke 1C and 2C AIS was frequent and associated with preoperative coronal balance and LIV selection. However, most patients with IPCD regained coronal balance through PCBR, which was significantly associated with immediately postoperative coronal balance. A fixation more distal to SV shifted the coronal balance further to the left postoperatively.
... [1][2][3][4] . Alguns autores atribuem esta complicação à falha na identificação da dupla curva verdadeira e à hipercorreção da curva torácica principal, prejudicando a capacidade compensatória da curva lombar [1][2][3][4][5] . ...
... . Alguns autores atribuem esta complicação à falha na identificação da dupla curva verdadeira e à hipercorreção da curva torácica principal, prejudicando a capacidade compensatória da curva lombar [1][2][3][4][5] . Em 1983, King et al. 6 descreveram uma classificação para ajudar na identificação dos tipos de curvas que poderiam ser tratadas por intermédio da artrodese seletiva. ...
... Um dos objetivos do tratamento cirúrgico da EIA é corrigir a deformidade com balanço coronal e sagital, ao mesmo tempo deixando livre da artrodese o maior número de segmentos possíveis para evitar complicações como a doença articular degenerativa dolorosa precoce dos segmentos não-artrodesados, em particular na região lombar [1][2][3]7,9 . A aplicação do conceito da artrodese seletiva torácica permite controlar e corrigir parcialmente a curva torácica principal, mantendo a mobilidade dos segmentos lombares. ...
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OBJECTIVE: to evaluate radiographic results regarding trunk decompensation of AIS treated with selective thoracic arthrodesis and 3ª generation instrumentation. METHODS: pre-operatory, immediately post-operatory and last radiography evaluations were carried out in 22 patients with adolescent idiopathic scoliosis AIS type King II treated with selective thoracic arthrodesis from 1993 to 2007. The percentage of correction of the thoracic and lumbar curve was observed by means of Cobb method, as well as the trunk coronal balance by using SRS criteria. RESULTS: after mean percentage of correction in thoracic curve of 56 ± 11% and 49 ± 13% in lumbar curve, we observed an immediate coronal decompensation in six patients (27.20%). After a mean 65-month follow-up, four patients (18.18%) showed trunk coronal decompensation. Only one patient needed a new surgery with arthrodesis extension, including the lumbar curve, due to lumbar curve decompensation. CONCLUSIONS: severe trunk decompensation in need of a second procedure for lumbar fusion was not a frequent complication in this series.
... This means that coronal balance might be maintained by the spontaneous correction of thoracolumbar/lumbar curves. The influence of the lumbar curve on the postoperative behavior of coronal balance has been previously studied [16]. It was proposed that the overcorrection of the thoracic curve relative to the lumbar curve was a risk factor for postoperative decompensation in some patients after STF [17]. ...
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Coronal decompensation is a common complication in Lenke 1 or 2 AIS patients after selective thoracic fusion (STF). However, the majority who developed immediately postoperative coronal decompensation experienced improvement and the related factors are not fully understood. The aim of this retrospective study was to investigate the prevalence of coronal imbalance in patients with Lenke 1 or 2 AIS and to explore radiological factors associated with spontaneous correction of coronal balance after surgery. Lenke 1 or 2 AIS patients receiving STF in our center from January 2013 to March 2015 were analyzed. Anteroposterior and lateral films were evaluated before surgery, at 1 month’s and 2 years’ follow-up. Patients were divided into 2 groups according to whether coronal imbalance occurred in the early postoperative period (1 month). Various radiological parameters as well as Scoliosis Research Society-22 were statistically compared between groups. Coronal decompensation was observed in 33 patients preoperatively, in 48 patients immediately postoperatively, and in 2 patients at final follow-up. Lowermost instrumented vertebra (LIV) disc angle (0.9° vs. 6.7°, p=0.019) and LIV- C7 plumb line and central sacral vertical line (CSVL) (-3.4mm vs. -13.7mm, p=0.020) increased in the final follow-up in the imbalanced group of type A modifier. The magnitude of lumbar curve was greater in the imbalanced group of type B or C modifier in the early postoperative period (19.5° vs. 12.6°, p=0.006; 25.5° vs. 13.7°, p<0.01), and this difference disappeared in the final follow-up. No differences in SRS-22 outcome scores were noted between groups in different time. Coronal imbalance was frequently detected immediately after STF in Lenke 1 or 2 AIS patients, with type C modifier slightly higher than A or B. Distal adding-on may help compensate for coronal imbalance in patients with type A modifier, while spontaneous correction of lumbar curve attributes to the improvement of coronal imbalance in patients with type B or C modifier.
... This observation is contrary to previous descriptions, in which the spontaneous lumbar correction was seen to be dynamic and the improvement would occur within the first two years after the surgery. 14,17,18 However, we observed that despite radiographic worsening, no significant clinical deterioration was observed. This can be explained by the fact that there was proportional accommodation of the instrumented TPR curve, which maintained the angular ratio between the curves. ...
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Objective: To evaluate the clinical and radiographic response of the lumbar curve after fusion of the main thoracic, in patients with adolescent idiopathic scoliosis of Lenke type 1. Methods: Forty-two patients with Lenke 1 adolescent idiopathic scoliosis who underwent operations via the posterior route with pedicle screws were prospectively evaluated. Clinical measurements (size of the hump and translation of the trunk in the coronal plane, by means of a plumb line) and radiographic measurements (Cobb angle, distal level of arthrodesis, translation of the lumbar apical vertebral and Risser) were made. The evaluations were performed preoperatively, immediately postoperatively and two years after surgery. Results: The mean Cobb angle of the main thoracic curve was found to have been corrected by 68.9% and the lumbar curve by 57.1%. Eighty percent of the patients presented improved coronal trunk balance two years after surgery. In four patients, worsening of the plumb line measurements was observed, but there was no need for surgical intervention. Less satisfactory results were observed in patients with lumbar modifier B. Conclusions: In Lenke 1 patients, fusion of the thoracic curve alone provided spontaneous correction of the lumbar curve and led to trunk balance. Less satisfactory results were observed in curves with lumbar modifier B, and this may be related to overcorrection of the main thoracic curve.
... Bizim serimizde lomber eğrilikteki takip döneminde tespit edilen düzelme oranı ortalama % 61,8 olarak hesaplandı. Lenke Tip 1 eğriliğe sahip AİS vakalarında PSF uygulandığında lomber bölgede spontan olarak düzelme meydana gelmektedir ve literatürdeki çalışmalar 2,3,6,7,[9][10][11][12][13]15,16 ve bizim çalışmamız bunu desteklemektedir. ...
... As stated by Von Lackum and Miller [20], it is desirable to achieve a correction of the primary thoracic curve that is not beyond the ability of the compensatory lumbar curve to balance the patient in selective thoracic fusion. When dealing with lumbar curves of a larger magnitude, the posterior approach, being capable of achieving strong corrective forces of the thoracic curve, is at risk of correcting the thoracic scoliosis beyond the capability of the lumbar curve to compensate and balance the spine in selective fusion for Lenke 1C [3,21,22]. Same perspectives had occurred in treatment for Lenke 5C curves. On one hand, for a balanced spine, complete correction of the instrumented curve was not suggested through anterior approach in Lenke 5C and a residual curve must be left to compensate the structural part of the thoracic curve [23]. ...
Article
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Introduction Posterior selective thoracolumbar or lumbar (TL/L) fusion with pedicle screw constructs for adolescent idiopathic scoliosis (AIS) has been studied in a few researches. However, few studies have discussed the indication for selective TL/L fusion and the behaviors of its adjacent disc angle. The present study aims to discuss the indication for posterior selective TL/L fusion and the behavior of the adjacent disc angle. Methods 45 consecutive cases of AIS undergoing posterior selective TL/L fusion were retrospectively evaluated, with an average follow-up of 36 months. Radiographs were reviewed to determine the coronal curve magnitude and the sagittal alignment preoperatively, postoperatively and at final follow-up. Thoracic curves in groups A had a correction loss of more than 5°, while thoracic curves in group B had a correction loss of not more than 5°. Results The coronal curve magnitude of the TL/L curve averaged 44° preoperatively and it was corrected to 6° immediately with a correction rate of 84.8 %. At final follow-up it was 9° with a correction loss of 3°. The minor thoracic curve was 26° preoperatively, and the convex side bending curve magnitude averaged 8° with a flexibility of 72.7 %. It was corrected to 13° immediately with a spontaneous correction of 48.5 %. At final follow-up it was 14° with a correction loss of 1°. UIVA decreased from 4° to 2° after surgery, and it was 2° at final follow-up. LIVA decreased from 7° to 4° after surgery, and it was 5° at final follow-up. Maximal correction of TL/L curves in group A is significantly less than that in group B. 1 patient received revision surgery to fuse the progressive thoracic curve. Conclusion Posterior selective TL/L fusion with pedicle screw constructs allows for spontaneous thoracic correction and maintains coronal and sagittal balance during the follow-up. Maximal correction instead of undercorrection was recommended for moderate Lenke 5C curves. Disc wedging could be improved after surgery and well maintained during the follow-up.
... There is evidence that surgical treatment for AIS is beneficial and reproducible, has controllable complications and is not deleterious (16)(17)(18)(19)(20)(21)(22)(23). Recent data also indicate that surgical treatment of AIS improves patient body image acceptance (24). ...
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OBJECTIVES The objective of this study was to evaluate whether the severity of deformities in patients with adolescent idiopathic scoliosis contributes to patients’ decision regarding whether to undergo an operation. METHODS We evaluated body image factors in adolescent idiopathic scoliosis patients. We evaluated the magnitude of the main scoliotic curve, gibbosity (magnitude and location), shoulder height asymmetry and patient’s age. We analyzed the correlation of these data with the number of years the patient was willing to trade for surgery, as measured by the time-trade-off method. RESULTS A total of 52 patients were studied. We did not find a correlation between any of the parameters that were studied and the number of years that the patient would trade for the surgery. CONCLUSIONS The magnitude of body deformities in patients with adolescent idiopathic scoliosis does not interfere with the decision to undertake surgical treatment.
... Once a surgeon has elected to perform STF for a thoracic curve with a large compensatory lumbar curve, there remains more controversy in the management of pre-operative coronal imbalance to the left. Few studies advocate for full intra-operative correction of the thoracic curve to attain coronal balance while others argue in favor of undercorrection of the thoracic curve in an attempt to match the SLCC [12,[17][18][19][20]. ...
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Purpose: Previous research has shown that with certain idiopathic scoliosis curve types, performing a selective thoracic fusion (STF) is associated with an increased risk of coronal decompensation post-operatively. The purpose of the current study was to determine the influence of curve correction and fusion level on post-operative balance in STF for adolescent idiopathic scoliosis patients with pre-operative coronal decompensation. Methods: A multicenter database was queried for subjects with right Lenke 1-4C curves, pre-operative left coronal imbalance, and 2-year follow-up who underwent STF (caudal fusion level of L1 or proximal). Rates of decompensation were compared between groups with different levels of fusion. Thoracic and lumbar curve correction as well as Scoliosis Research Society-22 outcome scores were compared between groups that were post-operatively balanced or persistently decompensated. Results: 121 patients were identified with average thoracic and lumbar curves of 53° and 41°. Mean pre- and post-operative decompensations were 2.4 ± 1.0 and 1.8 ± 1.1 cm, respectively. Eighteen patients were fused short, 62 to, and 41 were fused past the stable vertebra. Ten patients were fused short, 32 to, and 78 were fused past the neutral vertebra. Incidence of post-operative decompensation was 41%. No differences in post-operative decompensation relative to the stable or neutral vertebra were noted (p = 0.66, p = 0.74). Post-operatively, those patients who were balanced had similar thoracic curve correction (58%) to those decompensated (54%, p = 0.11); however, patients balanced post-operatively had greater SLCC (45 vs 40%, p = 0.04). No differences in SRS-22 outcome scores were noted between groups (p > 0.05). Conclusions: There was a high rate of post-operative decompensation in patients with pre-operative coronal decompensation undergoing STF. Fusion to or past the stable or neutral vertebra did not affect the risk of persistent decompensation. Attempts to improve SLCC could reduce post-operative decompensation.
... Selective fusion of the structural curve with an expectation of spontaneous correction of the non-structural compensatory curve is the basis of the selective posterior deformity correction (13)(14)(15)(16). However, in Lenke 5 C, immediate postoperative and late decompensation of coronal balance have been noted with selective posterior deformity correction (1,2,17). ...
Article
Background: Lenke 5 C curves are frequently associated with clinically and radiological coronal imbalance. Appropriate selection of proximal and distal levels of fusion is essential to ensure good coronal balance (CB). We aimed to evaluate radiological factors associated with (I) global CB in the early post-operative period; (II) late decompensation of CB; and (III) favourable spontaneous correction of CB on long term follow up. Methods: Twenty-three Lenke type 5C scoliosis cases treated with selective posterior lumbar instrumentation were retrospectively evaluated. Pre-operative, early post-operative and late post-operative (>2 years) whole length radiographs were analysed. Cobb's angle, lumbar lordosis, coronal imbalance, lower instrumented vertebra (LIV) tilt and translation and upper instrumented vertebra (UIV) tilt and translation were measured. The proximal and distal fusion levels were noted and correlated with post-operative CB. Results: There were 21 females and 2 males with a mean follow up of 36 months. The mean pre-operative cobb angle was 55°±13.26°, which corrected to 14.7°±8.84° and was maintained on follow up. Eight patients had early post-operative coronal imbalance with spontaneous resolution seen in six cases on long term follow-up. At final follow-up, four cases had coronal imbalance (persistent imbalance since early post-operative period =2; late decompensation =2). In cases with early imbalance 5/8 cases had a pre-operative LIV tilt of ≥25°. All four patients with coronal imbalance at final follow-up had pre-operative LIV tilt ≥25°. Radiographic parameters which correlated with post-operative coronal imbalance were pre-operative LIV tilt (r=0.64, P=0.001), pre-operative LIV translation (r=0.696, P<0.001), pre-operative UIV translation (r=0.44, P=0.030), post-operative LIV tilt (r=0.804, P<0.001), and post-operative UIV tilt (r=0.62, P=0.001). Conclusions: In Lenke 5C scoliosis, a pre-operative LIV tilt ≥25° significantly correlates with post-operative global coronal imbalance. Increasing UIV tilt may be a factor that accounts for improvement of CB in late follow-up period.
... The precise lumbar correction can be predicted using push prone side bending radiographs. 96,97 In Lenke 1A curves, the incidence of adding-on and progressive loss of correction increases dramatically when the vertebra below the lowest vertebra to be instrumented (LIV+1) deviates preoperatively from the central sacral vertical line by > 10 mm in patients with growth Follow us @BoneJointJ THE BONE & JOINT JOURNAL potential. 95 Various other strategies to decide the lowest instrumented vertebra in Lenke 1A curves so as to prevent add on including one considering the tilt of the L4 vertebra have been suggested. ...
Article
Adolescent idiopathic scoliosis (AIS) is a complex 3D deformity of the spine. Its prevalence is between 2% and 3% in the general population, with almost 10% of patients requiring some form of treatment and up to 0.1% undergoing surgery. The cosmetic aspect of the deformity is the biggest concern to the patient and is often accompanied by psychosocial distress. In addition, severe curves can cause cardiopulmonary distress. With proven benefits from surgery, the aims of treatment are to improve the cosmetic and functional outcomes. Obtaining correction in the coronal plane is not the only important endpoint anymore. With better understanding of spinal biomechanics and the long-term effects of multiplanar imbalance, we now know that sagittal balance is equally, if not more, important. Better correction of deformities has also been facilitated by an improvement in the design of implants and a better understanding of metallurgy. Understanding the unique character of each deformity is important. In addition, using the most appropriate implant and applying all the principles of correction in a bespoke manner is important to achieve optimum correction. In this article, we review the current concepts in AIS surgery. Cite this article: Bone Joint J 2018;100-B:415–24.
... El número de estudios con un seguimiento prolongado es limitado. Aunque la fusión selectiva tiene la ventaja de preservar la movilidad de los segmentos lumbares, en algunos casos, podría producirse la descompensación posoperatoria en el plano coronal 1,2,5 . Teniendo en cuenta esto, el desafío es pronosticar si el comportamiento del segmento lumbar no fusionado será agresivo o no evolutivo. ...
Article
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OBJECTIVE: To determine the outcome of lumbar segment without arthrodesis in the coronal plane, after selective thoracic fusions for with curvature of Lenke type 1 adolescent idiopathic scoliosis with curvature of Lenke type 1. METHODS: Twenty one patients were evaluated, with a mean follow-up of 29.71 months (range: 24-60 months) with retrospective clinical and radiographic analysis of patients with adolescent idiopathic scoliosis with curvature of Lenke type 1 (ABC). RESULTS: The increase of the angle of the lumbar curve without fusion was documented at the end of the follow-up in patients with coronal plane imbalance. CONCLUSION: Lumbar curve without fusion progressed at the end of the follow-up in patients with documented coronal plane imbalance (3/21).
... Essa constatação é contrária a descriç ões prévias de que a correção espontânea lombar seria dinâmica e melhoraria dentro dos dois primeiros anos após a cirurgia. 14,17,18 Entretanto, observamos que, apesar da piora radiográfica, não foi observada deterioração clínica relevante. Isso pode ser explicado pelo fato de ter havido acomodação proporcional da curva TPR instrumentada, fato que manteve a razão angular entre as curvas. ...
Article
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Avaliar a resposta clínica e radiográfica da curva lombar após a fusão da torácica principal, em pacientes com escoliose idiopática do adolescente (EIA) Lenke 1.
... In their series with 199 cases, Dobbs et al. 4) observed coronal imbalance in 5 cases. In 4 of those, the lumbar modifier was type C and in 1 of them the lumbar modifier was type B. These cases were also the ones in which an overcorrection was performed and the thoracic curve was corrected under 10°. ...
Article
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Purpose The aim of our study is to determine the alterations on coronal balance after overcorrection of Lenke type 1 curve, retrospectively. Methods Datas of 34 patients (29 female, 5 male patients; mean age, 16.3±3.3 years; range, 13-24 years) surgically treated for scoliosis between 2004 and 2010 were reviewed, retrospectively. The adolescent idiopathic scoliosis patients with Lenke type 1 curve treated with only posterior pedicle screw and postoperative thoracic curves less than 10° by Cobb method on frontal plane were enrolled in this study. Mean follow-up period was 52.5±29.7 months. Results The mean amount of the preoperative thoracic curves was measured as 41.2°±6.1° (range, 30°-56°). The mean amount of the early postoperative thoracic curves was measured as 6.5°±1.8° (range, 3°-9°). The mean amount of the thoracic curves was measured as 8.5°±4.6° (range, 3°-22°) during the last follow-up (p=0.01). The mean preoperative coronal balance was measured as 8.5mm(range, 1-30mm). The mean early postoperative coronal balance was measured as 3.5mm(range, 0-36 mm). The mean coronal balance was measured as 5.5mm(range, 0-38mm) during the last follow-up (p>0.05). Conclusion We suggest that Lenke type 1B and 1C should be carefully evaluated and the fusion levels should be accurately selected in order to maintain the correction of coronal balance. We suggest that selective fusion with overcorrection in Lenke type 1A are applied to curves that can be corrected lumbar curve at the preoperative bending radiograph and curves that not have coronal decompensation and >10° distal junctional kyphosis, preoperatively.
... Trata-se de uma classificação que utiliza três componentes: tipo da curva, modificadores lombares e modificadores torácicos. Esta classificação, de 2001, considera a deformidade em dois planos, orientando o cirurgião quanto às curvas principais e compensatórias, e, portanto, quanto à abordagem mais precisa e seletiva da deformidade, o que possibilita a fusão seletiva da curva torácica, preservando a curva lombar compensatória até em pacientes com modificador lombar do tipo C. [8][9][10] Em nossa série, foram obtidas as correções das curvas compensatórias com a artrodese seletiva apenas das curvas estruturadas, assim como proposto por Moe em 1972 apud Badra et al. 11 No presente trabalho, foi utilizada a técnica cirúrgica de terceira geração, com instrumentação posterior e haste dupla, visando assim menor sangramento per operatório, menor tempo cirúrgico e menor tempo de hospitalização como proposto também por Good et al. 12 Nesta série, os graus de correção obtidos estão de acordo com a literatura que aborda o tema, 13-15 sendo observados altos índices de correção das curvas no plano coronal, assim como de correção e manutenção do equilíbrio sagital, que conforme Brada et al. 11 é cada vez mais reconhecido como fundamental para o tratamento cirúrgico das escolioses idiopáticas. (Tabela 2) A manobra derrotatória é utilizada de rotina neste serviço para correção das curvas instrumentadas e não foram observadas descompensações nas curvas compensatórias decorridas dessa conduta; risco citado por Bridwell et al. 16 e por Lenke et al., 8 porém não observado na série de Suk et al. 14 Newton et al. 17 analisaram 203 pacientes com curvas de padrão 1B e 1C em um estudo multicêntrico. ...
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OBJECTIVE: To analyze the corrections obtained by selective thoracic segmental instrumentation using pedicle screws in patients with idiopathic scoliosis with lumbar B or C modificators. Determine the safety of the technique and decompensation of non-instrumented and instrumented compensatory curves. Observe the loss of the correction of instrumented and non-instrumented curves over the time. METHODS: Retrospective study of patients with idiopathic scoliosis curves types 1B, 1C, 2B and 2C who underwent surgical treatment via posterior approach using pedicle screws. The variables analyzed were: sex, age, levels affected by scoliosis, instrumented levels, number of inserted pedicle screws, classification according to Lenke, pre-surgical coronal and sagital Cobb angles (inclination included), immediate and late postoperative Cobb angles and the loss of the curve correction over the time. Twenty patients with idiopathic scoliosis underwent surgical selective treatment from August 2004 to October 2007. Eighteen of these patients were followed up and were included in this study they fulfilled the inclusion criteria. RESULTS: The average Cobb angle preoperatively was 52,61º, in the immediate postoperative, it was 17,89º and in the later postoperative, the Cobb angle was 22,15º, with an immediate mean correction of 34,72º and average correction loss of 4,26º at 39,78 months. An immediate average spontaneous correction of 22,62° was obtained in the non-instrumented compensatory curves and an average loss of 2,72º of this correction occurred at 39,78 months. There were no neurological complications, infections or decompensation of the lumbar curves. CONCLUSION: All patients showed substantial improvement in aesthetic terms, as well as in clinical and radiological aspects. Partial loss of correction occurred with time, but they did not lead to decompesation of non-instrumented curves. This study shows evidence of efficacy and safety of selective surgical treatment of idiopathic scoliosis using pedicle screws in the medium and long term.
... [50,127] The preoperative push prone and supine lumbar radiographs have been used to help predict the ideal amount of thoracic curve correction and expected amount spontaneous lumbar curve correction. [128] One study found up to 83% correction of the thoracic spine and 81% spontaneous correction of the lumbar spine when the preoperative flexibility imaging showed a spontaneous lumbar correction of 66%. [78] Other studies have shown similar results of spontaneous correction of lumbar curve between 60% and 81%, which corresponded to the 61%-83% surgical correction of the thoracic curve. ...
Article
The optimal surgical treatment of adolescent idiopathic scoliosis is heavily debated in the literature. This study aimed to review posterior surgical techniques in the treatment of adolescent idiopathic scoliosis. Literature review was performed. In treating adolescent idiopathic scoliosis with posterior spine fusion, there are many factors to consider when determining where to start and end the fusion construct: skeletal maturity, stress/bending radiographs, and assessment of vertebral rotation and translation. When considering selective thoracic fusion, the relative magnitudes of the main thoracic (MT) and thoracolumbar/lumbar (TL/L) curves and the overall sagittal profile of the thoracolumbar junction are assessed. Selective thoracic fusion can be appropriate if two of the three are found to be true: the MT-to-TL/L Cobb angle ratio is >1.2, the MT-to-TL/L apical vertebral translation (AVT) ratio is >1.2, and/or the MT-to-TL/L apical vertebral rotation (AVR) ratio is >1.2. Moreover, selective thoracic fusion can be an option in the presence of a nonstructural lumbar curve (bending Cobb angle
... Danilo et al. [1] conducted a retrospective cohort study of 42 Lenke 1 AIS patients and concluded that the main thoracic curve's overcorrection might result in less satisfactory results. Matthew et al. [23] indicated that the preoperative push-prone is the best preoperative flexibility radiograph to predict the final lumbar curve measurement. Pasha et al. [7] then developed a decision tree to define criteria for optimal lumbar curve correction following STF in Lenke 1 AIS. ...
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Objective To explore the characteristics of compensation of unfused lumbar region post thoracic fusion in Lenke 1 and 2 adolescent idiopathic scoliosis. Background Preserving lumbar mobility in the compensation is significant in controlling pain and maintaining its functions. The spontaneous correction of the distal unfused lumbar curve after STF has been widely reported, but previous study has not concentrated on the characteristics of compensation of unfused lumbar region post thoracic fusion. Method A total of 51 Lenke 1 and2 AIS patients were included, whose lowest instrumented vertebrae was L1 from January 2013 to December 2019. For further analysis, demographic data and coronal radiographic films were collected before surgery, at immediate erect postoperatively and final follow-up. The wedge angles of each unfused distal lumbar segments were measured, and the variations in each disc segment were calculated at the immediate postoperative review and final follow-up. Meanwhile, the unfused lumbar curve was divided into upper and lower parts, and we calculated their curve angles and compensations. Results The current study enrolled 41 females (80.4%) and 10 males (19.6%). Thirty-six patients were Lenke type 1, while 15 patients were Lenke type 2. The average main thoracic Cobb angle and thoracolumbar/lumbar Cobb angle were 44.1 ± 7.7°and 24.1 ± 9.3°, preoperatively. At the final follow-up, the disc wedge angle variation of L1/2, L2/3, L3/4, L4/5 and L5/S1 was 3.84 ± 5.96°, 3.09 ± 4.54°, 2.30 ± 4.53°, − 0.12 ± 3.89° and − 1.36 ± 2.80°, respectively. The compensation of upper and lower coronal lumbar curves at final follow-up were 9.22 ± 10.39° and − 1.49 ± 5.14°, respectively. Conclusion When choosing L1 as the lowest instrumented vertebrae, the distal unfused lumbar segments’ compensation showed a decreasing trend from the proximal end to the distal end. The adjacent L1/2 and L2/3 discs significantly contributed to this compensation.
... It exposes the patient to less radiation since it involves only a single film to evaluate all the curves versus previously mentioned techniques. 11,21,22,24 In a study on AIS patients, Cheh et al showed that a single preoperative supine radiograph was highly predictive of side-bending films and even showed a better negative predictive value for determining structurality of the minor curves compared to side-bending radiographs. 10 Our study is similar in methodology with that of Cheh et al. ...
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Study Design Retrospective cohort study. Objectives The purpose of the study is to evaluate the role of supine radiographs in determining flexibility of thoracic and thoracolumbar curves. Methods Ninety operative AIS patients with 2-year follow-up from a single institution were queried and classified into MT structural and TL structural groups. Equations were derived using linear regression to compute cut-off values for MT and TL curves. Thresholds were externally validated in a separate database of 60 AIS patients, and positive and negative predictive values were determined for each curve. Results MT supine values were highly predictive of MT side-bending values (TL group: 0.63, P < 0.001; MT group: 0.66, P = 0.006). Similarly, TL supine values were highly predictive of TL side-bending values (TL group: 0.56, P = 0.001 MT group: 0.68, P = 0.001). From our derived equations, MT and TL curves were considered structural on supine films if they were ≥ 30° and 35°, respectively. Contingency table analysis of external validity sample showed that supine films were highly predictive of structurality of MT curve (Sensitivity = 0.91, PPV = 0.95, NPV = 0.81) and TL curve (Sensitivity = 0.77, PPV = 0.81, NPV = 0.94). ROC analysis revealed that the area under curve for MT structurality from supine films was 0.931 (SEM: 0.03, CI: 0.86-0.99, P < 0.001) and TL structurality from supine films was 0.922 (SEM: 0.03, CI- 0.84-0.98, P < 0.001). Conclusions A single preoperative supine radiograph is highly predictive of side-bending radiographs to assess curve flexibility in AIS. A cut-off of ≥ 30° for MT and ≥ 35° for TL curves in supine radiographs can determine curve structurality.
... Traditionally, coronal balance (CB) is measured and quantified by the perpendicular distance between the coronal C7 plumbline (C7PL) and the central sacral vertical line (CSVL), with a value [20 mm being defined as imbalance [4]. Numerous studies have used the C7PL-CSVL distance as an assessment tool for surgical outcomes of AIS [5][6][7][8], but there is a paucity of data specifically addressing the postoperative CB in AIS [9], especially the ultimate CB after a long period of follow-up. ...
Article
Purpose To investigate which pre- and postoperative radiographic parameters are significantly correlated with the immediate postoperative coronal balance (CB) in Lenke 5C AIS patients, and to identify any radiographic parameter that is correlated with the ultimate CB at a minimum follow-up of 2 years. Methods Forty Lenke 5C AIS patients were recruited in the current study. Preoperative, immediate postoperative, and the latest follow-up radiographs were reviewed measuring various radiographic parameters related to UIV and LIV. The correlations between different parameters and CB were then studied. Results The average follow-up time was 35.2 months. Correlation analysis showed that the following radiographic parameters significantly associated with the immediate postoperative CB in Lenke 5C patients: preoperative CB (r = 0.66, p < 0.01), preoperative UIV translation (r = 0.61, p < 0.01), preoperative LIV tilt (r = 0.61, p < 0.01), postoperative UIV translation (r = 0.51, p < 0.05), and postoperative LIV tilt (r = 0.50, p < 0.05). At the last follow-up, only the final UIV tilt was inversely correlated with the ultimate CB (r = −0.58, p < 0.05). Seven patients presented with coronal imbalance immediately after surgery. However, only one of the seven patients presented with coronal imbalance at the last follow-up, and the other six achieved C7PL–CSVL distance within 10 mm. Conclusions In Lenke 5C patients, preoperative UIV translation and LIV tilt are two important parameters that can predict the immediate postoperative CB. During the postoperative follow-up, UIV tilt may play a very important role in compensating for postoperative coronal imbalance.
... The goal of surgical treatment of AIS is to correct deformity in the coronal and sagittal planes, through arthrodesis of the lowest number of segments possible, in order to avoid possible complications such as degenerative disease of the non-fused segments, principally in the lumbar region. [14][15][16][17] Applying the concept of selective arthrodesis permits us to control and partially correct the main thoracic curve, and to maintain the mobility of the segments, particularly in the lumbar segments. ...
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Objective : To radiographically evaluate the behavior of the secondary curves in the coronal and sagittal planes in patients with AIS classified as Lenke I, who underwent surgical treatment of selective arthrodesis by posterior approach. Methods : Retrospective study which analyzed 40 patients with AIS, being 33 female. The measurement of the radiographic parameters used followed the recommendations by Cobb. Results : The average correction of the thoracic proximal, primary and lumbar curves was 34.73%, 75.06% and 64.64%, respectively. Conclusion : Surgical treatment by selective arthrodesis in cases of AIS Lenke type I provide correction of compensatory curves in the coronal and maintenance in the sagittal plane.
... Compensatory lumbar/thoracolumbar curves: Dobbs et al. [24] have regarded push prone films to be of significant value in predicting the behavior of the lumbar curve after doing selective thoracic fusion in both anterior and posterior approach . Spontaneous lumbar/thoracolumbar curve correction is noted both in selective anterior and posterior corrective surgery, with some authors stating it to be better in anterior curve correction . ...
Article
Scoliosis is lateral curvature of the spine, which includes three-dimensional deformity. Both anterior and posterior approaches have been used to treat the deformity. Over the period of time, anterior scoliosis surgery has been popularized by various people albeit for selective indications. A literature review was done searching available literature from 1970 to 2019, using medical search engines, PubMed and Google Scholar. Review was aimed at defining the current status and indications for anterior surgery in adolescent idiopathic scoliosis. Anterior scoliosis surgery leads to similar correction compared to posterior surgery with additional advantage of saving of fusion levels along with preservation of more mobility. The pulmonary function affection from clinical standpoint remains limited with anterior approaches. Currently, anterior approaches are used for treating Lenke type 5 and 6 curves with similar results to posterior surgery. In addition, anterior approach can be an essential adjunct to posterior surgery in severe curves where there is significant stiffness.
Article
Study design: Retrospective radiographical review. Objective: To demonstrate that the structural and noncompensatory Lenke 3 and 4C lumbar curves could be nonstructural and compensatory. Summary of background data: Historically, Lenke 3 and 4C curves were not recommended for selective thoracic fusion (STF) because the lumbar curve was considered structural and noncompensatory. However, consecutive series of Lenke 3 and 4C curves suggest successful treatment with STF. Methods: Between 2001 and 2004, 2005 and 2008, and 2010 and 2012, 3 consecutive series of 108, 134, and 78 surgically treated Lenke 1, 2, 3, and 4C curves were reviewed, respectively. The coronal curve criteria for the curves treated with STF during each period were lumbar side bending Cobb angle less than 25° and meeting the Lenke ratio criteria, lumbar side bending Cobb angle 35° or less, and lumbar side bending Cobb angle 45° or less, respectively. The sagittal curve criteria for STF during each period was absence of junctional thoracolumbar kyphosis 20° or more between T10 and L2. The technique used for STF was the Guan-Din method. Radiographs of all the curves treated with STF were analyzed before and after surgery. Results: Optimal instrumented thoracic and compensatory lumbar correction was obtained for all Lenke 1, 2, 3, and 4C curves treated with STF in each period. As the coronal criteria for STF were broadened, the extent of feasibility of STF was expanded and the rate of STF increased. Although Cobb angle, apical vertebral translation, and apical vertebral rotation magnitudes of Lenke 3 and 4C curves were larger and more severe than those of Lenke 1 and 2C curves, optimal compensatory correction could still be obtained for Lenke 3 and 4C curves. Conclusion: The structural and noncompensatory Lenke 3 and 4C lumbar curves were proven to be nonstructural and compensatory. Lenke 1, 2, 3, and 4C curves have similar natures and similar responses to the same technique (Guan-Din method) used for STF and could be considered collectively as a single indication for STF. The extent of feasibility of STF could be expanded from Lenke 1 and 2 curves to Lenke 1, 2, 3, and 4 curves. Level of evidence: 2.
Article
Purpose of review: Our understanding of the etiology, evaluation, and management of idiopathic scoliosis continues to evolve. Relevant articles for this review published over the past year were selected to highlight the important advancements and contributions in idiopathic scoliosis. Recent findings: An increased interest in minimally invasive thorascopic spine approaches and procedures is reflected in the recent literature. Prone positioning for anterior thorascopic release has been shown to decrease operative time and the potential complications associated with single lung ventilation. Pedicle screw instrumentation of the thoracic spine has been demonstrated to provide significant rotational correction, which can decrease the need for thoracoplasty previously used to address the rib deformities associated with idiopathic scoliosis. Summary: Advances in our collective knowledge of idiopathic scoliosis on several levels continue to be made at a rapid pace. As investigators continue the search for possible genetic clues for the causes of idiopathic scoliosis, progress has been made in the evaluation, classification, and application of novel techniques that, it is hoped, will improve the outcomes in patients currently treated for idiopathic scoliosis.
Article
Correct identification of fusion levels in surgical planning for the management of adolescent idiopathic scoliosis is a complex task. Several classification systems and algorithms exist to assist surgeons in determining the appropriate levels to be instrumented. The Lenke classification is the benchmark system. Among the many factors and measurements that are taken into account when selecting the proper upper instrumented vertebra and lower instrumented vertebra are planning for selective fusion; preserving motion segments; preventing proximal and/or distal junctional kyphosis, shoulder imbalance, and neck pain; and maintaining short fusion lengths. Existing treatment algorithms do not account for every exception, and further research is required to improve long-term surgical outcomes.
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OBJETIVO: Identificar os sinais radiográficos preditivos de descompensação do tronco em pacientes com EIA King II (Lenke B e C) submetidos a artrodese torácica seletiva com material de terceira geração. MÉTODOS: Foram avaliadas retrospectivamente as radiografias pré-operatórias e do último acompanhamento de 22 pacientes. A amostra foi dividida em dois grupos: pacientes compensados após o tratamento (n=18) e os pacientes que apresentaram descompensação coronal (n=4). Esses dois grupos foram comparados para analisar possíveis critérios radiográficos pré-operatórios preditivos da descompensação do tronco. RESULTADOS: Os pacientes que evoluíram com descompensação coronal do tronco apresentaram maior valor angular, maior translação e maior rotação da vértebra apical da curva lombar e maior obliqüidade de L4 em relação à pelve. Além disso, a relação entre a curva torácica para os critérios de valor angular, TVA e RVA foi menor, quando comparadas com os pacientes com boa evolução. CONCLUSÕES: Curvas lombares compensatórias com valor angular semelhante à curva torácica principal, com translação e rotação da vértebra apical elevadas e grande inclinação de L4 apresentam alta probabilidade de descompensação do tronco após o tratamento cirúrgico. O número pequeno de pacientes descompensados não permitiu definir valores preditivos destas variáveis.
Article
Study design: A retrospective analysis of a prospectively collected multicenter database. Objective: To identify the radiographical and clinical outcomes in Lenke 3 curves fused selectively (S) versus nonselectively (NS). Summary of background data: Surgical treatment options for Lenke 3 curves include fusion of both curves (NS) or selective thoracic curve fusion (S). Selective fusion of the thoracic curve spares lumbar motion segments; however, it may result in marked residual deformity. Methods: A prospectively collected multicenter database was retrospectively reviewed for adolescent idiopathic scoliosis Lenke 3 curves treated with posterior spinal fusion with a minimum of 2 years of follow-up. Patients were divided into 2 groups: NS (nonselective fusion) and S (selective thoracic fusion). Radiographical and clinical data were compared between the groups using the unpaired Student t test and analysis of variance. Results: A total of 74 patients met our inclusion criteria, with 49 (66.2%) in the NS group and 25 (33.8%) in the S group. Overall, both groups were similar preoperatively except for lumbar Cobb (NS = 56.3°, S = 47.2°, P < 0.001), lumbar lordosis (NS = 56.9°, S = 67.2°, P = 0.001), lumbar rotational prominence (NS = 11.2°, S = 8.2°, P < 0.05), and lumbar apical translation (NS = 3.2 cm, S = 1.9 cm, P < 0.05). Postoperatively, NS fusion demonstrated significantly less coronal imbalance of 2 cm or less (NS = 10.2%, S = 56.0%, P < 0.001), better lumbar curve correction (NS = 68.2%, S = 51.9%, P < 0.001), better lumbar apical translation correction (NS = 1.2 cm, S = 2.1 cm, P < 0.01), and better percent correction of the lumbar prominence (NS = 66.5%, S = 40.4%, P < 0.05). Scoliosis Research Society Questionnaire 22 scores at 2 years were similar between the groups. Conclusion: Despite preoperatively smaller lumbar curves with less apical translation and lumbar prominence, most patients with selective fusions were out of balance postoperatively and had inferior radiographical outcomes as compared with their nonselective comparison cohort with similar patient-reported outcomes. Long-term follow-up is required to determine whether the trade-off of sparing motion segments at the expense of somewhat lessened radiographical outcomes is worthwhile.
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Background: Controversy still exists around surgical strategies for Lenke type 1C and 2C curves with primary thoracic and compensatory lumbar curves in adolescent idiopathic scoliosis (AIS). The benefit of selective thoracic fusion (STF) for these curve types is spontaneous lumbar curve correction while saving more mobile lumbar segments. However, a risk of postoperative coronal decompensation after STF has also been reported. This multicenter retrospective study was conducted to evaluate postoperative behavior of thoracolumbar/lumbar (TLL) curve and coronal balance after posterior thoracic fusion for Lenke 1C and 2C AIS. Methods: Twenty-four Lenke 1C and 2C AIS patients who underwent posterior thoracic fusion were included. The mean age of patients was 15.7 years old at time of surgery. Constructs used for surgery in all cases were pedicle screw constructs ending at L3 or above. Radiographic measurements were performed on Cobb angles of the main thoracic and TLL curves and coronal balance. Factors related to final Cobb angle of TLL curve and postoperative change of coronal balance were investigated. Results: Mean Cobb angles for main thoracic and TLL curves were 59.0° and 43.9° preoperatively, and were corrected to 21.5° and 22.0° at final follow-up, respectively. Mean coronal balance was -5.6 mm preoperatively and was corrected to -14.6 mm at final follow-up. Final Cobb angle of TLL curve was significantly correlated with immediate postoperative Cobb angle of main thoracic curve and tilt of lowest instrumented vertebra (LIV). Postoperative change of coronal balance was significantly correlated with selection of LIV relative to stable vertebra. Conclusion: Spontaneous correction of TLL curve occurred consistently by correcting the main thoracic curve and making the LIV more horizontal after posterior thoracic fusion for Lenke 1C and 2C AIS. The more distal fixation to stable vertebra resulted in coronal balance shifting more to the left postoperatively.
Article
Secondary Curve Behavior in Lenke Class IC Adolescent Idiopathic Scoliosis Following Video-Assisted Thoracoscopic Spinal Fusion and Instrumentation (Paper 29) Eugene J. Verzin, MD, FRCS, Mostyn R. Yong, MD, Maree T. Izatt, PT, Clayton J. Adam, PhD, Robert D. Labrom, MD, Geoffrey N. Askin, MD; Paediatric Spine Research Group, Queensland University of Technology & Mater Health Services, Brisbane, Australia BACKGROUND CONTEXT: Ideally after selective thoracic fusion for Lenke Class IB and IC (ie, major thoracic secondary lumbar) curves, the unfused lumbar spine will spontaneously accommodate to the corrected position of the thoracic curve, thereby achieving a balanced spine with the fusion mass centered over the pelvis, whilst avoiding the need for fusion of lumbar spinal segments. PURPOSE: The purpose of this study was to evaluate the behavior of the secondary lumbar curve in Lenke IC class adolescent idiopathic scoliosis (AIS) following video-assisted thoracoscopic spinal fusion and instrumentation (VATS) of the major thoracic curve. STUDY DESIGN/SETTING: A retrospective review of 22 consecutive patients with AIS who underwent VATS by a single surgeon was conducted. The results were compared to published literature examining the behavior of the lumbar compensatory curve in Lenke IC curves when other surgical approaches were employed. PATIENT SAMPLE: Twenty-two consecutive patients with AIS who underwent VATS by a single surgeon. OUTCOME MEASURES: Cobb angle measurements were performed on pre-operative (including bending films) and post-operative standing AP and lateral radiographs to evaluate the magnitude of the thoracic major curve and the lumbar secondary curve. Pre-operative and post-operative clinical rib hump measurements were performed. METHODS: Twenty-two patients (all female) underwent surgery for Lenke IC AIS. All major thoracic curves were convex to the right. The average age at surgery was 14 years (range 10 to 22 years). On average 6.7 levels (6 to 8) were instrumented. The mean follow-up was 25.1 months (6 to 36). Cobb angle measurements were performed on pre-operative (including bending films) and post-operative standing AP and lateral radiographs to evaluate the magnitude of the thoracic major curve and the lumbar secondary curve. Pre-operative and post-operative clinical rib hump measurements were performed. Univariate ANOVA was performed on the results to determine statistical significance. RESULTS: The pre-operative major thoracic Cobb angle measured on average 53.8 degrees� (range, 40� to 75�). The pre-operative secondary lumbar Cobb angle measured on average 43.9 degrees� (range, 34� to 55�). On bending films, the secondary curve corrected to 11.3� degrees (range, 0� to 35�). The rib hump measured 15.0 degrees� (range, 7� to 21�). At latest follow-up the major thoracic Cobb angle measured on average 27.2� degrees (20� to 41�) (p<0.001) and the mean secondary lumbar curve was 27.3 degrees� (15� to 42�) (p<0.001). This represented a correction factor of 37.8%. The rib hump measured 6.5 degrees� (2� to 15�) at last follow-up (p<0.001). The figures demonstrated were comparable to published series when open surgery (both anterior and posterior approach) was performed. CONCLUSIONS: VATS is an effective method of correcting major thoracic curves with secondary lumbar curves resulting in a balanced spine. The behavior of the secondary lumbar curve is consistent with published series when open surgery, both anterior and posterior, is performed. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
Article
Study design: A review of a multicenter, prospective registry of patients surgically treated for adolescent idiopathic scoliosis. Objective: To investigate preoperative and postoperative distribution of coronal decompensation in Lenke 1C curves and to determine whether a selective thoracic fusion (STF) affects the results of coronal decompensation. Summary of background data: Numerous causes of postoperative coronal decompensation in Lenke 1C curves have been reported; however, there are few reports focusing on preoperative decompensation and its relation to postoperative decompensation in Lenke 1C curves. Methods: Patients with Lenke 1C prospectively collected from a multicenter study were analyzed. Preoperatively, patients were grouped as decompensated (C7-CSVL > 2 cm) or balanced (C7-CSVL within 2 cm, where CSVL is central sacral vertical line). Preoperative distribution and factors for postoperative coronal decompensation were investigated. Results: Seventy-one patients (53 STF, 18 nonselective fusions) were included. Preoperatively, coronal balance was skewed to the left (-17 ± 13 mm). Of the 21 STF decompensated to the left preoperatively, 12 (57%) remained to the left at 2 years. Postoperative thoracic correction was significantly better in those balanced postoperatively (57%) compared with those who remained decompensated (46%; P < 0.05). There were 32 STF patients who were balanced preoperatively, with 10 of these (31%) decompensated to the left at 2-year follow-up. This rate (31%) was significantly less than the group that was decompensated preoperatively (57%, P = 0.04). In the nonselective fusion group, 16 out of 18 patients (89%) were balanced at 2-year follow-up, independent of preoperative balance. Conclusion: Patients with Lenke 1C tended to be decompensated to the left preoperatively. In those decompensated preoperatively who underwent a STF, the majority remained greater than 2 cm to the left at 2-year follow-up. Patients with both thoracic and lumbar curves fused had better coronal balance at 2 years than selectively treated patients. Although not a contraindication to performing a selective fusion, treating surgeons should be prepared for modest coronal decompensation in 40% of patients with Lenke 1C treated with selective fusion of the thoracic curve alone. Level of evidence: 3.
Article
Object: Lenke 1C curves are challenging to manage surgically due to the structural thoracic deformity and nonstructural lumbar curve. Selective thoracic fusion (STF) is considered the standard of care because it preserves motion of the lumbar segment, yet nonselective STF (NSTF) remains prevalent. This study aims to identify baseline patient characteristics that drive treatment and to compare postoperative outcomes for both procedures. Methods: Studies that compared baseline and postoperative demographic data, health-related quality of life (HRQL) questionnaires, and radiographic parameters of patients with Lenke 1C curves undergoing STF or NSTF were identified for meta-analysis. The effect measure is expressed as a mean difference (MD) with 95% CI. A positive MD signifies a greater STF value, or a mean increase within the group. Results: One prospective and 6 retrospective case-control studies with sample size of 488 patients (344 STF and 144 NSTF) were identified. Baseline age, sex, and HRQLs were equivalent, except for better scores in the STF group for the Scoliosis Appearance Questionnaire (SAQ): Unrelated to Deformity item (3.47 vs 3.88, p = 0.01) and the Spine Research Society questionnaire, Item 22: Pain (4.13 vs 3.92, p = 0.04). Radiographic findings were significantly worse in NSTF, as measured by the thoracolumbar/lumbar (TL/L) Cobb angle (MD: -4.29°, p < 0.01) and TL/L apical vertebral translation (AVT) (MD: -6.08, p < 0.01). Radiographic findings significantly improved in STF, as measured in the main thoracic (MT) Cobb angle (MD: -27.78°, p < 0.01), TL/L Cobb angle (MD: -16.24°, p < 0.01), MT:TL/L Cobb ratio (MD: -0.21, p < 0.01), coronal balance (MD: 0.47, p = 0.02), and thoracic kyphosis (MD: 7.87°, p < 0.01); and in NSTF in proximal thoracic (PT) Cobb angle (24° vs 14.1°, p < 0.01), MT Cobb angle (53.5° vs 20.5°, p < 0.01), and TL/L Cobb angle (41.6° vs 16.6°, p < 0.01). Postoperative TL/L Cobb angle (23.1° vs 16.6°, p < 0.01) was significantly higher in STF; but PT Cobb angle, MT Cobb angle, and MT:TL/L Cobb ratio are equivalent. Conclusions: Patients with larger lumbar compensatory curves displaying a larger degree of coronal translation, as measured by the TL/L AVT, are more likely to undergo an NSTF. Contrary to established guidelines, larger MT curve magnitudes and MT:TL/L Cobb angle ratios have not been found to influence the decision to pursue a selective thoracic fusion. Although overall both STF and NSTF groups are found to have effective postoperative coronal balance, the STF group has only modest improvements in the lumbar curve position as determined by a relatively unchanged TL/L AVT. Furthermore, surgeons may prefer NSTF in patients who may have a worse overall perception of their spinal deformity as measured by HRQL measures of pain and desire for appearance change.
Article
Retrospective radiographical review. To evaluate the outcome of selective thoracic fusion (STF) by using the Guan-Din method for the treatment of major thoracic compensatory lumbar (MTCL) curves. Performing STF for MTCL curves is to minimize the loss of lumbar motion and the risk of lumbar degeneration or pain. Surgical treatment of MTCL curves aims to maximize the rate of STF for MTCL curves while optimizing instrumental thoracic and compensatory lumbar correction. The Guan-Din method has been demonstrated to be able to enhance the lumbar curve's capacity for spontaneous correction and broaden the current curve criteria of MTCL curves for STF. Between 2004 and 2010, 510 consecutive surgically treated MTCL curves were reviewed. Of these MTCL curves, who met the criteria of lumbar side bending Cobb 35° or less and without global thoracic hyperkyphosis and/or thoracolumbar kyphosis (T10-L2 ≤20°), were treated with STF using the Guan-Din method. Radiographs were analyzed before surgery, immediately after surgery, and at the most recent follow-up (range, 2-8 yr). Curve types of 510 MTCL curves according to Lenke system were as follows: 1A (n = 91), 2A (n = 74), 3A (n = 6), 4A (n = 2), 1B (n = 93), 2B (n = 34), 3B (n = 8), 4B (n = 5), 1C (n = 84), 2C (n = 26), 3C (n = 72), and 4C (n = 15). Of the 510 MTCL curves, 458 (90%) curves were treated with STF. A mean 73% thoracic correction and 63% lumbar correction was obtained at the most recent follow-up. Of the 197 surgically treated MTCL curves with a lumbar C modifier, 148 (75%) curves that contained 57 Lenke 1C and 2C curves and 40 Lenke 3C and 4C curves that did not meet Lenke curve criteria for STF, were successfully treated with STF. A mean 67% thoracic correction and 57% lumbar correction was obtained at the most recent follow-up. The rate of STF and the magnitude of correction of MTCL curves in this study were significantly greater than those in all other reports. No significant change in global coronal and sagittal imbalance was observed. The rate of STF and the compensatory correction of MTCL curves could be maximized by using the Guan-Din method as the method for STF.Level of Evidence: 4.
Article
Study design: Multicenter review of prospectively collected data. Objective: To analyze the natural history of uninstrumented compensatory curves prospectively during a 5-year postoperative period in patients with selectively fused Lenke type 1C and 5C adolescent idiopathic scoliosis. Summary of background data: After a selective fusion for 1C and 5C adolescent idiopathic scoliosis curve types, there is concern that uninstrumented compensatory curves will continue to progress over time. However, to date, there have been no studies using prospectively collected data beyond 2 years to determine the natural history of these uninstrumented compensatory curves. Methods: Lenke 1C and 5C adolescent idiopathic scoliosis cases, prospectively collected from a multicenter study were analyzed. All patients underwent a selective fusion (1C only thoracic curve fused; 5C only thoracolumbar/lumbar curve fused). Preoperative, first-erect, 1-year, 2-year, and 5-year postoperative coronal, sagittal, and axial (Perdriolle) radiographical outcomes were compared using repeated measures analysis of variance with Bonferroni post hoc comparisons (P < 0.05). Results: Twenty-four selectively fused Lenke 1C curves and 21 selectively fused Lenke 5C curves were reviewed. Preoperative compensatory curve Cobb angles were 40° ± 6° and 25° ± 9°, respectively. In Lenke 1C curves, the uninstrumented compensatory lumbar curves were corrected by 32% ± 16% at first erect, 44% ± 17% correction at 1 year, 38% ± 15% correction at 2 years, and 39% ± 19% at 5 years. In Lenke 5C curves, the uninstrumented compensatory thoracic curves were corrected by a mean of 37% ± 29% at first erect, 42% ± 29% at 1 year, 37% ± 29% at 2 years, and 30% ± 23% at 5 years. The sagittal and axial measures of the compensatory curves remained stable during the postoperative period. Conclusion: In Lenke 1C and 5C adolescent idiopathic scoliosis deformity patterns fused selectively, the uninstrumented compensatory curves adjust to match the instrumented primary curve and do not seem to progress between 1 and 5 years postoperatively.
Article
Study Design Retrospective cohort Study. Objectives To identify predictive factors for coronal imbalance after selective fusion in adolescent idiopathic scoliosis (AIS) with Lenke type 1 curves. Methods AIS patients with Lenke type 1 curve with A, B and C lumbar modifiers underwent selective thoracic fusion. The curve fulcrum flexibility and fulcrum bending correction index (FBCI) was studied. Coronal imbalance was defined as more than 2 cm of truncal shift or more than 2 cm list at two-year follow-up. Results A total of 301 patients were included in the study. Coronal imbalance at two-year follow-up was found in 38 patients (13%). At the preoperative stage, we found a significant difference in main curve flexibility with 66±15% in the balanced group and 60±15% in the imbalanced group (P = .032). At the immediate postoperative stage, mean curve correction was 71±13% vs 70±13% and mean FBCI was 112±29% vs 122±29% in the balance and unbalanced group, respectively (P = .031). Postoperative FBCI of more than 125% (third quartile) resulted in an odds ratio of 2.1 (95%CI:1.1-4.3) for coronal imbalance at two years (P=.031). No significant changes in fusion mass or LIV tilt was observed. Conclusions A decreased preoperative flexibility and a higher FBCI was significantly associated with coronal imbalance. A high FBCI is an indication of a curve correction that exceeds the inherent flexibility of the spine, and our results add to a growing body of evidence that “overcorrection” of the main curve can lead to postoperative imbalance.
Article
Background: Selective fusions of the structural curve remain a common treatment strategy for adolescent idiopathic scoliosis, yet long-term outcomes are not well-understood. The purpose of this study was to report 10-year prospective radiographic and patient-rated outcomes of selective fusions of the main thoracic (MT) or thoracolumbar/lumbar (TL/L) curve, with particular attention to the behavior of the uninstrumented, compensatory curve. Methods: A prospectively collected multicenter database was used to identify patients who had been followed regularly for least 10 years after a selective MT or TL/L fusion for adolescent idiopathic scoliosis. Interval radiographs were evaluated for coronal and sagittal Cobb angles as well as overall coronal balance. Scores on the Scoliosis Research Society Questionnaire (SRS-24) were catalogued and evaluated. Radiographic outcomes and SRS-24 scores were compared between preoperative and postoperative time points using repeated-measures analysis of variance. Individual patient records were screened for recent curve progression of >5°, and these cases were methodically evaluated. Results: Fifty-one patients with selective fusions (21 MT and 30 TL/L) for adolescent idiopathic scoliosis who had been followed for at least 10 years were identified. The instrumented MT and TL/L curves were corrected by an average of 51% and 60%, respectively, at 10 years. The uninstrumented, compensatory curves had gradual spontaneous correction that approached the magnitude of the fused curve at 5 years postoperatively, with the correction maintained at 10 years. This led to excellent coronal balance. A subgroup of patients had recent progression of the primary curve adjacent to the prior fusion or within the instrumented segments, resulting in a compensatory progression of the uninstrumented curve. On the whole, SRS scores did not decrease during follow-up, and no patient had secondary operations. Conclusions: Selective fusion of a primary thoracic or lumbar curve in properly selected patients with adolescent idiopathic scoliosis will result in spontaneous correction of the uninstrumented curve and a durable result for at least 10 years. Level of evidence: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.
Article
Purpose: The purpose of this study was to determine the relationship between pre-operative scoliosis flexibility and post-operative outcomes, including curve correction and complications, for patients who have been treated with growth friendly surgery (GFS) for early onset scoliosis (EOS). Methods: The study was conducted as a retrospective review of prospectively collected data from an international, multicenter, EOS database. EOS patients with pre-operative flexibility radiographs (traction or bending) were identified. Pre-operative flexibility and immediate post-operative correction were calculated for each patient. Post-operative complications were recorded at final follow-up. Pearson correlations were determined for flexibility vs correction for all patients and were compared between etiologies and between device types (MCGR, TGR, VEPTR). Results: 107 patients (14 congenital, 43 neuromuscular, 31 syndromic, 19 idiopathic) with mean age 7.1 years at index surgery were identified. Mean pre-operative scoliosis was 77°. Mean flexibility of 36% was not significantly different between etiologies. Mean immediate post-operative scoliosis was 46° (p < 0.001 vs. pre-operative) with mean correction of 38%. Correction rate was not significantly different between etiologies; however, correction rate was different between device types (MCGR 45%, TGR 40%, VEPTR 14%; p = < 0.001). Pearson correlation for flexibility vs correction was fair (r = 0.37, p < 0.001). This correlation was observed for idiopathic (r = 0.53, p = 0.020) and neuromuscular (r = 0.46, p = 0.0020) scoliosis, but not for congenital or syndromic scoliosis. At a mean of 6.1 year follow-up (minimum 2 years to 15.5 years), 60 of 81patients (74%) experienced at least one complication. Odds ratio for developing a complication was 3.00 (1.03-8.76) for patients with pre-operative flexibility < 45% (p < 0.05). Conclusions: As lower pre-operative flexibility was associated with less scoliosis correction and with a higher risk of post-operative complications, curve flexibility should be considered when deciding upon the timing of growth friendly surgery. Level of evidence: Level III-retrospective comparative study.
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Objective To explore the characteristics of compensation of unfused lumbar region post selective thoracic fusion in Lenke 1 and 2 adolescent idiopathic scoliosis Background Preserving lumbar mobility in the compensation is significant in controlling pain and maintaining its functions. The spontaneous correction of the distal unfused lumbar curve after STF has been widely reported, but previous study has not concentrated on the characteristics of compensation of unfused lumbar region post selective thoracic fusion. Method A total of 51 Lenke 1 and2 AIS patients were included, whose lowest instrumented vertebrae was L1 from January 2013 to December 2019. For further analysis, demographic data and coronal radiographic films were collected before surgery, at immediate erect postoperatively and final follow-up. The wedge angles of each unfused distal lumbar segments were measured, and the variations in each disc segment were calculated at the immediate postoperative review and final follow-up. Meanwhile, the unfused lumbar curve was divided into upper and lower parts, and calculated their curve angles and compensations. Results The current study enrolled 41 females (80.4%) and 10 males (19.6%). 36 patients were Lenke type 1, while 15 patients were Lenke type 2. The average main thoracic Cobb angle and thoracolumbar/lumbar Cobb angle were 44.1±7.7°and 24.1±9.3°, preoperatively. At the final follow-up, the disc wedge angle variation of L1/2, L2/3, L3/4, L4/5 and L5/S1 was 3.84±5.96°, 3.09±4.54°, 2.30±4.53°, -0.12±3.89° and -1.36±2.80°, respectively. The compensation of upper and lower coronal lumbar curves at final follow-up were 9.22±10.39° and -1.49±5.14°, respectively. Conclusion When choosing L1 as the lowest instrumented vertebrae, the distal unfused lumbar segments' compensation showed a decreasing trend from the proximal end to the distal end. The adjacent L1/2 and L2/3 discs significantly contributed to this compensation.
Article
Managing patients with coronal imbalance (CI) and shoulder height asymmetry following scoliosis surgery can be challenging. Little is known about the course of findings over time and whether they improve or persist. The aim was to report the rate of suboptimal radiographic CI or shoulder asymmetry (SA) at 5 years in patients who were already reported to have CI or SA 2 years after surgery for adolescent idiopathic scoliosis (AIS). An AIS database was reviewed for patients with both 2- and 5-year follow-up after surgery. From this cohort, patients with CI>2 cm or SA>2 cm at their 2-year follow-up were identified and reevaluated, using the same parameters, at 5-year follow-up. Of 916 patients, 157 (17%) patients had CI and 69 (8%) patients had SA at 2-year follow-up. At 5 years this improved to 53 (6%) and 11 patients (1%), respectively. Having coronal or shoulder imbalance 2 years after surgery for AIS does not guarantee continued imbalance 5 years after surgery. Most patients demonstrate some improvement in these measures of clinical deformity. Anticipating the potential course following a postoperative coronal balance and shoulder height differences can help surgeons manage and counsel their patients appropriately. Level II—therapeutic.
Article
Study design: This was a retrospective comparative study. Objective: To evaluate long-term outcomes of selective thoracic fusion (STF) using both rod derotation (RD) and direct vertebral rotation (DVR) with pedicle screw instrumentation (PSI) in the treatment of thoracic adolescent idiopathic scoliosis (AIS) with a minimum 10-year follow-up. Summary of background data: Postoperative compensation and maintenance of the unfused lumbar curve after STF is very important factor for the satisfactory results in the treatment of thoracic AIS. Patients and methods: Sixty-five patients with thoracic AIS treated with STF from the neutral vertebra (NV) to NV or NV-1 with RD and DVR were retrospectively analyzed with a minimum 10-year follow-up. Patients were divided into 2 groups: satisfactory (n=52) and unsatisfactory groups (n=13). Unsatisfactory results were defined as an adding-on, a lowest instrumented vertebra (LIV) tilt of >10 degrees, or coronal balance >15 mm. Results: No significant differences were observed in the main thoracic curve between the satisfactory and unsatisfactory groups postoperatively (P=0.218) and at the last follow-up (P=0.636). Significant improvements of LIV tilt and disk angle were observed in both groups, but these improvements deteriorated during the follow-up period in the unsatisfactory group. Significant differences of apical vertebra (AV) and end vertebra (EV) were observed postoperatively (AV: P=0.001, EV: P=0.001) and at the last follow-up (AV: P<0.000, EV: P<0.000) between the 2 groups. Conclusions: STF using RD and DVR can achieve satisfactory deformity correction for thoracic AIS with satisfactory compensatory lumbar curve that was maintained over long-term follow-up. Progression of unfused lumbar curve closely related with LIV tilt and disk angle showing insufficient DVR. Therefore, STF with sufficient DVR required to achieve satisfactory deformity correction and prevent a distal adding-on phenomenon in the treatment of thoracic AIS.
Article
Objective: To analyze the effects of direct vertebral rotation (DVR) on radiologic outcomes in the treatment of thoracic adolescent idiopathic scoliosis after selective thoracic fusion with pedicle screw instrumentation. Methods: Adolescent idiopathic scoliosis patients with single thoracic curves (n = 110) treated by selective thoracic fusion with a minimum of 2 years of follow-up were retrospectively analyzed. The patients were separated into 2 groups: non-DVR (n = 63) and DVR (n = 47). Results: There was a significant difference in fused segments between the non-DVR and DVR groups (P < 0.001). There was also a significant difference in main thoracic curve postoperatively (P = 0.001) and at the last follow-up (P = 0.006) between the non-DVR and DVR groups. However, there was no significant difference in proximal thoracic and lumbar curves postoperatively (proximal thoracic curve: P = 0.186; lumbar curve: P = 0.155) and at the last follow-up (proximal thoracic curve: P = 0.250; lumbar curve: P = 0.060) between the 2 groups. Significant improvements in the lowest instrumented vertebra tilt and disc angle were noted but then slight deteriorations in such were observed during the follow-up period in the non-DVR group. The prevalence of unsatisfactory results was 20.6% (13 of 63) in the non-DVR group and 19.1% (9 of 47) in the DVR group, with no significant difference (P = 0.522). Conclusions: For correcting single thoracic adolescent idiopathic scoliosis by selective thoracic fusion with pedicle screw instrumentation, the addition of DVR to the surgical procedure showed comparable radiologic outcomes compared with non-DVR procedures.
Article
Study design: This is a retrospective single-center and single-surgeon study. Objective: The present study examined for preoperative parameters having the highest correlation with compensatory thoracolumbar/lumbar (TL/L) curve correction 2 years after surgery in adolescent idiopathic scoliosis (AIS) patients with Lenke type 1 curves. Summary of background: Several parameters have been considered to evaluate the flexibility of compensatory TL/L curve in AIS patients with Lenke type 1 curves. However, the imaging position with the strongest correlation with postoperative spontaneous TL/L curve correction is unknown. Data: In total, 37 patients with AIS Lenke type 1 curves who had undergone skip pedicle screw fixation were followed for a 2-year period were enrolled. Materials and methods: TL/L Cobb angles measured at the standing posteroanterior view, supine position, supine position with maximum bending, supine position with traction, prone position, and prone-push position were determined before surgery. Using TL/L Cobb angles determined 2 years postoperatively, correlations between preoperative and postoperative Cobb angles were calculated for each position using the Spearman rank-correlation coefficient, linear regression analysis, and paired t tests. Results: Mean preoperative mean±SD TL/L Cobb angle was significantly improved from 31±9 to 13±8 degrees at the study end point. In analyses of correlations between postoperative TL/L Cobb angle and preoperative parameters, the supine position with traction was most strongly associated with TL/L curve correction rate at 2 years after surgery (r=0.72; P<0.01), with paired t tests revealing a significant mean difference of 3.1 degrees. Conclusions: Preoperative Cobb angle evaluated at the supine position with traction had the strongest correlation with spontaneously corrected TL/L curve Cobb angle after selective thoracic fusion for AIS Lenke type 1 curves. Accordingly, it may be sufficient to evaluate TL/L curve correction at this position only to reduce radiation exposure and operative time.
Article
Study Design Multicenter, retrospective cohort study. Objectives The purpose of this study is to determine how the amount of residual lowest instrumented vertebra (LIV) tilt correlates with radiographic measurements. Summary of Background Data When performing a selective thoracic posterior spinal fusion for adolescent idiopathic scoliosis (AIS), the LIV may be tilted into the lumbar curve or made horizontal. Methods This is a multicenter retrospective study of 33 consecutive patients with AIS, Lenke types 1 to 4, lumbar modifier C, and a minimum follow-up of 2 years, who underwent selective thoracic posterior spinal fusions. Measurements obtained from pre- and postoperative radiographs were correlated with postoperative LIV tilt. Results At final follow-up, less postoperative LIV tilt significantly correlated with less thoracic apical translation (p = .023) when controlling for the position of the LIV relative to the stable vertebra and preoperative thoracic and lumbar curve flexibility. LIV tilt was not significantly associated with thoracic Cobb angle, lumbar Cobb angle, lumbar apical translation, coronal balance, sagittal balance, or the amount of correction obtained compared to their preoperative measurements (p > .05). Conclusion Decreased LIV tilt was significantly associated with decreased thoracic apical translation. LIV tilt did not significantly correlate with coronal balance or any other radiographic measurement. We caution that these findings may only be applicable in C modifier curves and when the correct LIV is chosen. Level of Evidence Level III, Therapeutic study.
Article
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Introduction: Controversies still exist in the surgical indications and outcomes of selective thoracic fusion (STF) for a primary thoracic curve with a compensatory large lumbar curve (King-Moe type II/Lenke 1C curve) in adolescent idiopathic scoliosis (AIS). Issues of the greatest concern regarding this curve type include curve criteria that indicate STF to prevent postoperative coronal decompensation and postoperative radiographic outcomes, including curve correction, coronal balance, and thoracolumbar kyphosis, after STF. Methods: This review comprehensively documents the issues raised in the literature regarding surgical indications and radiographic outcomes of STF for King-Moe type II/Lenke 1C curve in AIS. Results: Studies suggest that radiographic curve criteria indicating STF for this curve type include the preoperative dominance of the thoracic curve to the lumbar curve in the Cobb angle and the characteristics of the lumbar curve in magnitude and flexibility. Studies warn the need for a careful clinical evaluation of the thoracic and lumbar rotational prominences. Documented radiographic outcomes of importance include the postoperative behavior of the unfused lumbar curve, coronal or sagittal decompensation after STF, and factors associated with these issues. A comprehensive review of the literature suggests that the use of a segmental pedicle screw construct and better instrumented thoracic curve correction achieve better spontaneous lumbar curve correction. Although the causes of postoperative coronal decompensation remain multifactorial, preoperative coronal decompensation to the left and an inappropriate selection of the lowest instrumented vertebra are consistently reported to be the major causative factors. Conclusions: STF has been validated in general for the treatment of King-Moe type II or Lenke 1C curve in AIS; however, controversies remain regarding the surgical indications and outcomes. Long-term impacts of residual lumbar curve, coronal decompensation, and mild thoracolumbar kyphosis on clinical outcomes after STF, along with optimal indications and strategy for STF, should further be assessed.
Article
Background context: In Lenke 1C and 2C curves, the choice between selective thoracic fusion (STF) versus non-selective thoracic fusion (NSTF) as the optimal surgical treatment is controversial. Objective: To assess the radiological and clinical outcome of patients with Lenke 1C/2C curves treated with STF. Study design: Retrospective study PATIENT SAMPLE: 44 METHODS: 44 Lenke 1C/2C AIS patients curves who underwent STF were reviewed. Radiological parameters and SRS-22r scores were assessed preoperatively, postoperatively and on final follow-up. The incidence of coronal decompensation, lumbar decompensation and adding-on phenomenon were reported. Results: Mean follow-up duration was 45.1 ± 12.3 months and mean age was 17.0 ± 5.1 years. The preoperative MT:TL/L Cobb angle ratio was 1.4 ± 0.3 and the MT:TL/L AVT ratio was 1.6 ± 0.8. Final follow-up coronal balance was -13.0 ± 11.5mm, main thoracic apical vertebra translation (AVT) was 6.9 ± 11.8mm, and lumbar AVT was -20.4 ± 13.8mm (p<0.05). Lumbar Cobb angle improved from 47.5 ± 7.8o to 24.9 ± 8.2o after operation and 23.3 ± 9.8o at final follow-up. The spontaneous lumbar curve correction rate was 50.9%. Nine (20.5%) patients had coronal decompensation, four (9.1%) patients had lumbar decompensation and 11 (25.0%) patients had adding-on phenomenon. We did not perform any revision surgery. The SRS-22r scores improved significantly in the overall scores, self-image and mental health domain. Conclusions: STF led to improvement in the radiological and clinical outcome for Lenke 1C/2C patients. Although no patients required revision surgery, the rate of coronal decompensation, lumbar decompensation and adding-on phenomenon are significant.
Chapter
Idiopathic scoliosis is the most common form of scoliosis seen in children. Other forms of scoliosis are of neuromuscular, syndrome related or congenital origin. Current evidence suggests that idiopathic scoliosis is a polygenic, multifactorial condition with a variable expression and severity of the deformity. As idiopathic scoliosis presents as a painless deformity in early childhood or mostly at onset of the pubertal growth spurt, school screening programs contribute to an early diagnosis. Conservative treatment consisting of corrective corsets and physiotherapeutic scoliosis specific exercises remain the mainstay of treatment in milder curves. Severe deformity with curves of more than 50° necessitate operative treatment. The demanding therapeutic challenge of this condition is to prevent progression of the curves during growth, as well as choosing the right time for surgical intervention. Clinical presentation, classification, conservative and surgical treatment options, decision making and the correlation with other chestwall deformities in idiopathic scoliosis are discussed to provide a state of the art diagnostic and treatment tool.
Article
Background context: Shoulder imbalance, coronal decompensation, and adding-on phenomenon following corrective surgery in adolescent idiopathic scoliosis patients are known to be related to the fusion level selected. Although many studies have assessed the appropriate selection of the proximal and distal fusion level, no definite conclusions have been drawn thus far. Purpose: We aimed to assess the problems with fusion level selection for corrective surgery in patients with adolescent idiopathic scoliosis, and to enhance understanding about these problems. Study design/setting: A narrative review METHODS: We conducted a literature search of fusion level selection in corrective surgery for adolescent idiopathic scoliosis. Accordingly, we selected and reviewed 5 debatable topics related to fusion level selection: (1) selective thoracic fusion; (2) selective thoracolumbar/lumbar (TL/L) fusion; (3) adding-on phenomenon; (4) distal fusion level selection for major TL/L curves; and (5) proximal fusion level selection and shoulder imbalance. Results: Selective fusion can be chosen in specific curve types, although there is a risk of coronal decompensation or adding-on phenomenon. Generally, wider indications for selective fusions are usually associated with more frequent complications. Despite the determination of several indications for selective fusion to avoid such complications, no clear guidelines have been established. Although authors have suggested various criteria to prevent the adding-on phenomenon, no consensus has been reached on the appropriate selection of lower instrumented vertebra. The fusion level selection for major TL/L curves primarily focuses on whether distal fusion can terminate at L3, a topic that remains unclear. Furthermore, due to the presence of several related factors and complications, proximal level selection and shoulder imbalance has been constantly debated and remains controversial from its etiology to its prevention. Conclusions: Although several difficult problems in the diagnosis and treatment of adolescent idiopathic scoliosis have been resolved by understanding its mechanism and via technical advancement, no definite guideline for fusion level selection has been established. A review of five major controversial issues about fusion level selection could provide better understanding of adolescent idiopathic scoliosis. We believe that a thorough validation study of the above-mentioned controversial issues can help address them.
Chapter
Radiographic assessment is an integral component of the evaluation and management of lumbar scoliosis. Although lumbar deformity is relatively common, the complexity and uniqueness of a patient’s specific deformity and symptoms necessitates a thorough assessment of each individual case. Fortunately for patients and clinicians, modern imaging modalities permit the evaluation of the bony, neuromuscular, and soft tissue components of the spine with exquisite detail. The spine surgeon is equipped with many tools used to evaluate a patient radiographically with guidance based on history, physical exam, and specific clinical questions. Some of these tools include conventional radiography, computed tomography (CT), and magnetic resonance imaging (MRI), each of which may be adapted or occasionally substituted as necessary to glean specific information. The primary goal of this chapter is to introduce the imaging modalities used to assess patients during each phase of evaluation and their applications to particular clinical scenarios.
Article
Study design: A retrospective cohort study. Objective: To determine radiographic parameters, including the lowest instrumented vertebral (LIV) tilt, related to the postoperative magnitude and progression of residual lumbar curves (LCs) in adolescent idiopathic scoliosis (AIS) patients who underwent posterior spinal fusion (PSF) with LIV at or above L1. Summary of background data: Although several guidelines have been proposed for thoracic curve fusion (TCF), factors related to the postoperative magnitude and potential progression of unfused LCs remained undetermined. The effect of the LIV tilt on residual LCs is also unclear. Methods: Patients with Lenke type 1-4 curves who underwent PSF with LIV at or above L1 with a minimum follow-up period of 2 years were evaluated. Prediction models for residual LCs were developed using multivariate linear regressions with selected radiographic parameters. Subgroup analyses, followed by sensitivity tests, were then performed for variables best predicting the progression of residual LCs. Results: A total of 130 patients were included. Multivariate linear regression analysis showed that the immediate postoperative LIV-tilt angle was associated with the immediate postoperative LCs and the prediction model for residual LCs, with high accuracy (R=0.93 and 0.77, respectively). Sensitivity tests revealed immediate postoperative LIV-tilt angle <10° and correction rate of main thoracic curve (MTC) Cobb angle > 53% as predictors for progression of residual LCs, and they reached moderate discrimination when combined together as one criterion (OR=16.3, 95%CI=5.3-50.1; sensitivity=89%, specificity=67%, PPV=51%, NPV=94%). Conclusion: The current study revealed that LIV tilt, as an operable factor during surgery, is not only a determinant in prediction models showing high correlation with the magnitude of postoperative LCs but a predictor for progression of residual LCs. "Immediate postoperative LIV-tilt angle <10° and correction rate of MTC Cobb angle >53%", as a united criterion, could serve as a predictor for progression of residual LCs.
Article
Study design: Multicenter; review of prospectively collected data. Objective: To determine the risks and potential benefits of nonselective versus selective fusion in a matched set of patients with Lenke 5 curves. Summary of background data: The Lenke classification suggests a limited thoracolumbar/lumbar fusion for type 5 curves, although many experienced adolescent idiopathic scoliosis surgeons, at times, include a fusion of the thoracic curve. METHODS.: Prospectively collected cases from a multicenter database were analyzed. Patients with Lenke type 5 scoliosis curves were divided into 2 groups: 109 selective or short (only thoracolumbar/lumbar curve fused), and 41 nonselective or long (both thoracolumbar/lumbar and thoracic curves fused). Patients were then matched on the basis of the preoperative radiographical and clinical measures. Two-year postoperative radiographical and clinical outcomes were compared, using analysis of variance, with Bonferroni correction (P < 0.008). Results: Twenty-nine matched pairs (58 patients) with Lenke 5 curves were identified. There were no preoperative differences between groups in age, thoracic or lumbar Cobb angle, curve flexibility, thoracic kyphosis, clinical trunk flexibility, or Scoliosis Research Society outcomes questionnaire scores. Postoperatively, patients in the nonselective group exhibited greater coronal correction for thoracic (residual Cobb; 22° vs. 12°) and lumbar curves (residual Cobb; 19° vs. 13°). However, the longer fusions had significantly less thoracic kyphosis (27° vs. 18°), truncal side bending (14 vs. 10 cm), and rotational flexibility (53° vs. 42°). There was no difference in clinical balance or Scoliosis Research Society questionnaire, version 22, scores. Conclusion: Adolescent idiopathic scoliosis surgeons attempt to achieve balanced correction with the fewest motion segments fused. Our data suggest that fusion of the thoracic curve in primary thoracolumbar scoliosis may improve coronal correction, but at the cost of decreased thoracic kyphosis and clinical flexibility 2 years postoperatively.
Article
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Coronal decompensation following correction of adolescent idiopathic scoliosis (AIS) has been reported to be due to the Cotrel-Dubousset rod derotation maneuver, or to a hypercorrection of the main thoracic curve. The treatment of such decompensation consists classically in observation, bracing, or extension of the instrumentation in the lumbar spine for a King 2 curve, or in the upper thoracic spine for a King 5 curve. As the postoperative decompensation is related to a hypercorrection of the main thoracic curve (relative to the compensatory curve), we hypothesized that if we were to "let the spine go" to some of its initial deformity, the balance of the patient would be improved. The purpose of the study was therefore to report on two cases where a postoperative imbalance following scoliosis surgery was successfully treated by decreasing the correction of the main thoracic curve. Two patients with AIS were found to have significant imbalance after scoliosis surgery. Both patients had been treated for a right thoracic curve (82 degrees and 85 degrees respectively) with an anterior release and posterior instrumentation. The revision surgery consisted for both patients in removing all the hooks between the end vertebrae of the main thoracic curve. This was done before the 3rd postoperative month for both patients. After revision surgery, the balance of both patients improved dramatically within a few weeks. The shoulders became almost level, and the trunk shift improved concomitantly. The Cobb angle increased by 8 degrees and 10 degrees, and the apical vertebra shifted to the right by 15 and 10 mm for the respective patients. These results were stable at 1-year follow-up. In the event of a persisting imbalance, we recommend, in selected cases, letting the spine go by removing all the implants located between the end vertebrae of the main thoracic curve. This adjustment or fine-tuning of the instrumentation should be done before the fusion takes place, and is best achieved with an instrumentation in which the hooks can be easily removed from the rod.
Article
Study Design. A retrospective study by an independent observer of a consecutive series of 67 cases of adolescent idiopathic scoliosis presenting with a King II curve pattern. Objectives. To demonstrate the validity of a selective thoracic fusion as a treatment of King II curves with special attention to immediate postoperative and long‐term trunk balance in the coronal and sagittal planes. Summary of the Background Data. The literature has been fairly controversial in terms of the recommended treatment of King II curve patterns in adolescent idiopathic scoliosis. The main confusion appears to be whether the thoracic curve alone or both curves should be instrumented and fused. Methods. Sixty‐seven patients were identified as having had a selective posterior thoracic spine fusion with instrumentation between 1961 and 1994. None of these cases had a fusion of the lumbar spine. Preoperative radiographs were analyzed for determination of the appropriate fusion level using the criteria of the stable and neutral vertebra. Follow‐up radiographs were evaluated for balance in the coronal and sagittal planes using the central sacral line on posteroanterior radiograph and the C7 sacral promontory line on lateral film. Results. At 2‐year or greater follow‐up, the unfused lumbar curve remained equal to or less than the corrected thoracic curve in 63 patients (94%). No patient required extension of fusion. Frontal plane balance analysis showed that 47 of the 67 patients had the T1 plumb line within 2 cm of the midline for an average decompensation of 8.7 mm. In no patient was the loss of balance greater than 3.8 cm. Sagittal plane balance analysis showed that only one patient had inferior junctional kyphosis greater than 10°. This did not require extension of fusion. There were no cases of superior junctional kyphosis. Conclusions. The concept of selective thoracic fusion in the King II curve pattern appears to be valid. These findings suggest that arthrodesis of the lumbar spine can be avoided when this pattern is properly diagnosed and appropriately treated. Proper identification of the stable and neutral vertebra and of the appropriate level of fusion are important to achieve good postoperative balance. Successful preservation of lumbar motion segments is important to long‐term satisfactory outcome in adolescent idiopathic scoliosis.
Article
The selection of fusion levels in thoracic idiopathic scoliosis was subjected to multicenter retrospective review to test the validity of the classification system and recommendations of King et al. The 253 patients reviewed were treated by posterior fusion and Harrington instrumentation. Bending films were of little help in selecting fusion levels. Standing radiographs alone were usually adequate. King Type II curves may yield better lumbar correction if the lumbar curve is partially included in the fusion. Type IV curves may be safely fused one level proximal to the stable vertebrae.
Article
We evaluated the results of segmental fixation of the spine with Cotrel-Dubousset instrumentation in ninety-five patients who had adolescent idiopathic scoliosis. The instrumentation was used in an attempt to achieve three-dimensional correction of the scoliosis, maintain lumbar lordosis, create thoracic kyphosis, and avoid the need for a postoperative cast or brace. The patients were followed for twenty-four to sixty-four months (average, thirty-five months). Cotrel-Dubousset instrumentation provided an average correction of the coronal curve of 48 per cent at the time of the most recent follow-up. The normal sagittal curves at the thoracolumbar junction and in the lumbar spine were maintained, and the thoracic kyphosis was increased slightly (average, +7 degrees). Apical translation improved an average of 60 per cent, and apical rotation improved an average of 11 per cent. Forced vital capacity improved an average of 21 per cent, and the one-second forced expiratory volume improved an average of 18 per cent. There were no major neurological deficits. A symptomatic pseudarthrosis developed in one patient. Postoperatively, decompensation of the spine developed in five of the first twenty-six patients who had a Type-II or Type-III curve. This complication was avoided in the last twenty-four patients who had a Type-II or Type-III curve by means of a stricter adherence to the definition of a Type-II curve, and reversal of the bend of the rod and the hooks between the caudal neutral and stable vertebrae. The major advantages of Cotrel-Dubousset instrumentation are the stable fixation that is achieved and the preservation of segmental lumbar lordosis.
Article
Twenty-four patients with King Type II scoliosis were retrospectively studied to determine if preoperative assessment of lumbar curve flexibility was predictive of postoperative spinal balance. All patients had preoperative lumbar curves exceeding 40 degrees and all underwent selective thoracic fusion with Cotrel-Dubousset or Texas Scottish Rite Hospital instrumentation. The lumbar curves corrected 73% on preoperative bend radiographs. Despite this significant flexibility, the lumbar curves remained larger after surgery than the instrumented thoracic curves and spinal imbalance occurred. This finding was due, in part, to postoperative persistence of obliquity between L4 and the pelvis. When using Cotrel-Dubousset or Texas Scottish Rite Hospital instrumentation, preoperative assessment of the large lumbar curve's flexibility is not particularly helpful in predicting its response to selective thoracic fusion, especially regarding whether postoperative imbalance may occur.
Article
Between 1985 and 1988, 50 adolescent idiopathic scoliosis patients with either King Type II (n = 19) or III (n = 31) curves were treated with Cotrel-Dubousset instrumentation and had a minimum of 2-year follow-up. Five of these patients had early postoperative decompensation, and have provided important lessons for the future prevention and treatment of these imbalances. Most problematic was distinguishing between King Type II and double major curve patterns. Proper identification of King Type II curves, which may be successfully treated with selective thoracic fusion, requires careful analysis of the standing preoperative coronal radiograph as well as the side benders. Thus, we now define Type II curves based on the differential between the thoracic and lumbar curve magnitude, apical vertebral deviation from the midline, and apical vertebral rotation on the standing coronal radiograph in addition to a positive flexibility index.
Article
The purpose of this study is to determine the usefulness of the King classification in predicting decompensation in adolescent idiopathic scoliosis. Fifty-one patients were reviewed with a mean follow-up of 25 months. Five patients had Type 1 adolescent idiopathic scoliosis: four were treated with Zielke/Cotrel-Dubousset instrumentation or Zielke instrumentation alone. Correction was greater than 51% in these cases and there was no decompensation. Twenty-three patients had Type II scoliosis. Nineteen of whom were treated with Cotrel-Dubousset instrumentation; 3 with Zielke and Cotrel-Dubousset instrumentation, and 1 with Zielke. The best correction occurred with anterior/posterior instrumentation. Decompensation occurred in 9 patients, all of whom were treated with Cotrel-Dubousset instrumentation alone. Fourteen patients had Type III scoliosis. All were treated with Cotrel-Dubousset instrumentation with correction of 65%. Decompensation occurred in 4 patients, all of whom were fused to or beyond the stable vertebra. Four patients had Type IV scoliosis; all were fused short of the stable vertebra with Cotrel-Dubousset instrumentation, resulting in correction of 52% and no decompensation. Five patients had Type V instrumentation; four were treated with Cotrel-Dubousset instrumentation and 1 with Zielke. There was no relationship between level of fusion and decompensation. Based on this study, the authors contend that the King classification is a valuable tool in the selection of type of instrumentation and fusion level.
Article
Although well accepted in the patient undergoing Harrington instrumentation, the validity of King's criteria in patients undergoing correction of idiopathic scoliosis using the Cotrel-Dubousset system has been questioned. The cases of 64 patients with Type II (N = 40) and Type III (N = 24) idiopathic scoliosis treated with Cotrel-Dubousset instrumentation were reviewed. The average curve correction for Type II spinal curvature was 69.4% after surgery and 57.8% at follow-up examination. Decompensation was evident in 40% of the curves that were fused beyond the stable vertebra. However, the patients were only aware of their trunk decompensation if it was larger than 10 mm, and this was found in 35% of the patients. Decompensation occurred in 60% of those that were fused short of or to the stable vertebra. Only 42% of this group were aware of their decompensation. Decompensation was measured to the left of the spine in all patients. The difference between the subgroups based on the choice of distal fusion levels was not statistically significant (P greater than 0.05). The average curve correction for Type III scoliosis was 62.9% after surgery and 54.6% at the time of follow-up examination. There was no correlation between caudal fusion levels and the incidence of decompensation with Type III curves. It was concluded that there was no statistically significant relationship between choice of distal fusion level and the amount of decompensation, thereby indicating that the use of King's criteria for the selection of fusion levels in patients undergoing correction of idiopathic scoliosis using the Cotrel-Dubousset instrumentation may not be useful.
Article
Spinal decompensation after Cotrel-Dubousset (C-D) instrumentation in the King type II curve pattern has become a recognized complication secondary to progression of the unfused lumbar curve. Twenty-three patients with type II curves who underwent selective thoracic fusion according to the guidelines established by King et al. were reviewed. Mean follow-up was 19.5 months. Lumbar curves greater than 45 degrees associated with a low flexibility index were significantly more likely to develop postoperative progression of the uninstrumented lumbar curve with resultant spinal decompensation, suggesting that in these curves the King criteria for selective thoracic fusion may not be appropriate.
Article
Spinal imbalance following Cotrel-Dubousset (CD) instrumentation for adolescent idiopathic scoliosis is a problem that is recognized with increasing frequency. We reviewed the clinical records and radiographs of 41 consecutive patients treated with CD instrumentation and attempted to identify factors related to postoperative worsening of spinal balance. Spinal balance was determined by the perpendicular distance of C7 to the center sacral line. Twenty-five were decompensated postoperatively. Sixteen patients had balance that was worse relative to the preoperative films. Eleven of 16 patients with worsened balance postoperative were King type III curves. Of 16 patients with worsened balance postoperatively, 13 had been fused to or below the lower neutral vertebra. Overcorrection of either the primary curve or the composite curve (sum of the measurable curves) relative to the preoperative bending films was not related to postoperative worsening of spinal balance. Fusion to the neutral or stable vertebra with CD instrumentation runs a high risk for postoperative worsening of spinal balance when the derotation maneuver is used. Consideration should be given to avoiding the derotation maneuver in larger type II curves in order to preserve spinal balance and avoid extension of instrumentation into the middle or lower lumbar spine.
Article
From 1985 to 1987, 82 patients with idiopathic scoliosis followed 12 to 44 months underwent selective fusion and correction of their right thoracic curves by Cotrel-Dubousset instrumentation using the "derotation" maneuver. Preoperative, postoperative, and follow-up standing anteroposterior roentgenograms of the spine were analyzed. For curves in which there was deviation from the midline (plumb line) and rotation of the lumbar segments, an increased incidence of decompensation was produced after surgery, when posterior Cotrel-Dubousset instrumentation and fusion were carried to the "stable" vertebra with one rod bend and hook alignment on the left sided derotation rod. Previous guidelines established for selective fusion with conventional posterior instrumentation (Harrington or Luque rods) may not be applicable to derotation with Cotrel-Dubousset instrumentation.
Article
Spinal decompensation after corrective surgery for scoliosis appears to be a significant problem after Cotrel-Dubousset instrumentation (CDI). CDI produces torsional changes in the instrumented and uninstrumented spine that could result in spinal imbalance. Preoperative and postoperative three-dimensional analysis including computed tomography (CT) scans to measure vertebral rotation and segmental rotation were performed to evaluate the importance of torsional changes. Moe/King Type II deformities had a substantially greater risk of imbalance. Deformities instrumented over fewer spinal segments were less likely to decompensate. Specifically, instrumentation excluding the mobile transition segment, determined by maximum segmental rotation and segmental Cobb angle, was likely to decompensate. Derotation and deformity correction excessive in relation to preoperative side bending flexibility and segmental rotation frequently resulted in imbalance. Spinal imbalance after CDI can be reduced by avoiding overcorrection and inclusion of mobile transition segments.
Article
One hundred sixty patients with idiopathic scoliosis underwent preoperative and postoperative sagittal plane analysis of the thoracic spine, thoracolumbar junction, and lumbar spine. The data suggest that mild to moderate improvements in thoracic hypokyphosis are possible. When crossing the thoracolumbar junction, reversal of rod bend and reversal of hooks on the derotation rod appears to provide the most physiologic sagittal contour. Cotrel-Dubousset instrumentation to the mid and distal lumbar spine can preserve and, at times, enhance lumbar lordosis.
Article
The behavior of the unfused lumbar curve was evaluated radiographically in 58 cases of adolescent idiopathic thoracic scoliosis that had a selective thoracic fusion only. The lumbar scoliosis echoed the correction obtained in the thoracic scoliosis both immediately postoperatively and at an average 2 1/2-year follow-up. In the sagittal plane, although correction was obtained in the thoracic hypokyphosis, there were no changes seen in the lumbar lordosis at final follow-up. Segmental instrumentation was more effective in correcting thoracic scoliosis and hypokyphosis, but did not alter the behavior of the lumbar curve. The caudal extent of the fusion relative to the stable vertebra did not measurably alter the operative results in either curve or plane.
Article
Postoperative decompensation has been reported following Cotrel-Dubousset instrumentation for right thoracic idiopathic scoliosis. The authors examined balance in the frontal and sagittal planes in 53 patients to determine optimal levels for fusion. King et al Type II curves, particularly larger ones, shifted to the left when the thoracic curve was fused to the stable vertebra or just below. Most Type III curves balanced well regardless of the levels fused. One-third of all patients developed mild radiographic junctional kyphosis at the lower level instrumented, more commonly when instrumentation ended at or above T12. The authors recommend fusing one segment short of the stable vertebra in most Type II curves. Large Type II curves need both curves fused for optimal balance. Type III curves can be fused short of the stable vertebra.
Article
Three hundred and fifty-two patients had a one-stage posterior spinal arthrodesis between 1960 and 1984 using one of four types of instrumentation: a Harrington distraction rod, Harrington distraction and compression rods, Harrington distraction and compression rods with a device for transverse traction, and a Harrington distraction rod with sublaminar wires. All of the patients were female (age-range, eleven to nineteen years), and all had idiopathic scoliosis with a single right or double thoracic curve. The minimum length of follow-up was two years. No significant difference was found among the four groups relative to the amount of correction that was obtained at operation or maintained two years after operation. An average of 13.5 per cent of correction was lost during follow-up in the patients who were treated with postoperative immobilization, and an average of 27 per cent was lost in the patients who were treated with sublaminar wires without immobilization. The use of a straight Harrington rod reduced normal thoracic kyphosis, the addition of a compression rod corrected hyperkyphosis, and the use of a rod with sublaminar wires corrected thoracic hypokyphosis or thoracic lordosis.
Article
This is a preliminary report on Cotrel-Dubousset (CD) instrumentation for the surgical management of idiopathic thoracic scoliosis. From September 1985 through April 1986, 37 patients were treated at the authors' hospital, by posterior spinal fusion with CD instrumentation. Twelve patients had surgical treatment of spinal deformity associated with other disorders or had revision surgery. The remaining 25 patients, with no prior surgery, were diagnosed as having juvenile or adolescent idiopathic scoliosis. After operation, this group of patients was routinely noted to have significant improvement in rib deformity. This is associated with the rotational correction achieved with CD instrumentation and contrasts with the minimal rib deformity correction with Harrington instrumentation documented by some workers. In this series, no rib resections have been necessary in conjunction with CD instrumentation. No postoperative external immobilization was used. Ambulation began on the second postoperative day, and patients were discharged five to seven days after operation. Gradual resumption of normal activities was allowed at six weeks, and full activities, other than contact sports, after three months.
Article
From the material and data reviewed in our study of 405 patients, it appears that postoperative correction of the thoracic spine approximately equals the correction noted on preoperative side-bending roentgenograms. Selective thoracic fusion can be safely performed on a Type-II curve of less than 80 degrees, but care must be taken to use the vertebra that is neutral and stable so that the lower level of the fusion is centered over the sacrum. The lumbar curve spontaneously corrects to balance the thoracic curve when selective thoracic fusion is performed and the lower level of fusion is properly selected. In Type-III, IV, and V thoracic curves the lower level of fusion should be centered over the sacrum to achieve a balanced, stable spine.
Article
The evaluation and management of scoliosis curves depend on careful study and curve classification. This article discusses current concepts of curve classifications and analyzes Type II curves in particular in hopes of making it easier to manage these curves from both nonoperative and operative standpoints.
Article
Frontal plane geometry of postoperative curves was analyzed using a geometric model to investigate the relationship between coronal decompensation and postoperative apical shifts from the center sacral line for various thoracic and lumbar Cobb angles. To determine if a balanced spinal configuration is possible when the postoperative lumbar curve is larger than the thoracic curve, and to determine the limits on the postoperative magnitude of the lumbar curve relative to the thoracic curve beyond which a spinal configuration with acceptable balance cannot be achieved. Previous studies have suggested that overcorrection of the primary thoracic curve may be the principal cause of coronal decompensation after selective thoracic correction and fusion in King Type II curves. Also, other causative factors, such as inappropriate selection of fusion levels and hook patterns, have been implicated as possible reasons for decompensation after Cotrel-Dubousset instrumentation for idiopathic scoliosis. Postoperative thoracic curves of 20 degrees, 25 degrees, and 30 degrees were simulated on a model spine. For each thoracic Cobb angle, three left lumbar curves were simulated with the lumbar curve larger than thoracic by 5 degrees, 10 degrees, and 15 degrees. For each combination of thoracic and lumbar Cobb angles, spinal configurations corresponding to different lateral shifts of the thoracic and lumbar apical vertebrae from the center sacral line were obtained. For a given combination of postoperative thoracic and lumbar Cobb angles, there is an optimal range of postoperative lateral distance between the thoracic and lumbar apices (relative apical distance) that will maintain acceptable balance (decompensation < or = 10 mm). Smaller values of the relative apical distance will decompensate the spine. For a constant postoperative thoracic Cobb angle, the postoperative distance between the thoracic and lumbar apices needed to maintain a balanced spine increases with increasing postoperative lumbar Cobb angle. Similarly, for a constant difference between the postoperative thoracic and lumbar Cobb angles, the postoperative distance between the thoracic and lumbar apices needed to maintain a balance spine increases with increasing postoperative thoracic Cobb angle. For postoperative thoracic curves of 20 degrees-30 degrees, acceptable balance can be achieved when the magnitude of the postoperative lumbar curve is up to twice the thoracic curve as long as adequate postoperative relative apical distance can be maintained. Decompensation does not appear to be caused by the relative magnitudes of the postoperative thoracic and lumbar curves, but is a result of inadequate relative distance between the thoracic and lumbar apical vertebrae in the postoperative geometry.
Article
The basic principles of current idiopathic scoliosis treatment are three-dimensional correction and rigid fixation. Although it is accepted that Cotrel-Dubousset instrumentation (CDI) meets these goals, there is concern about the potential risk of trunk imbalance and spinal decompensation during the derotation manoeuvre. The results of 45 patients with idiopathic scoliosis treated with CDI between December 1988 and August 1992 were retrospectively analysed. Mean age was 14.3 years and mean follow-up period was 48.6 months. An average correction of 49.6% was achieved in the major curves. The best results were obtained in King type III curves, with a 69.4% correction. Spinal imbalance was evaluated by measuring lateral trunk shift (LT), shift of head (SH) and shift of stable vertebra (SS). Decompensation was measured by the increase in secondary curves. When all curve types were included, the average preoperative LT value of 1.96 vertebral units (VU) was brought down to 0.91 VU postoperatively, achieving a 55.9% correction. Fourteen patients had an SH value of zero preoperatively and remained balanced after instrumentation. Of the 41 remaining patients, 21 achieved an SH value of zero postoperatively. When all cases were included, the average preoperative SH value was 1.0 VU, which was corrected to 0.42 VU with CDI (69% correction). An average correction of SS of 75.5% was obtained, with the mean preoperative value of 0.73 VU being corrected to 0.19 VU. At the last follow-up visit, a secondary curve had formed above the major curve in one patient, and three patients had a junctional kyphosis. Loss of correction in the frontal plane correlated with loss of correction of LT. The rigid and semiflexible lumbar curves had a tendency to progress when they were not instrumented, especially in type II curves. Junctional kyphosis could be prevented when concave laminar claws were used in the thoraco-lumbar region. It was concluded that spinal decompensation and imbalance could be minimized with careful preoperative planning, avoidance of overcorrection and use of long instrumentation in double major curves.
Article
A retrospective study by an independent observer of a consecutive series of 67 cases of adolescent idiopathic scoliosis presenting with a King II curve pattern. To demonstrate the validity of a selective thoracic fusion as a treatment of King II curves with special attention to immediate postoperative and long-term trunk balance in the coronal and sagittal planes. The literature has been fairly controversial in terms of the recommended treatment of King II curve patterns in adolescent idiopathic scoliosis. The main confusion appears to be whether the thoracic curve alone or both curves should be instrumented and fused. Sixty-seven patients were identified as having had a selective posterior thoracic spine fusion with instrumentation between 1961 and 1994. None of these cases had a fusion of the lumbar spine. Preoperative radiographs were analyzed for determination of the appropriate fusion level using the criteria of the stable and neutral vertebra. Follow-up radiographs were evaluated for balance in the coronal and sagittal planes using the central sacral line on posteroanterior radiograph and the C7 sacral promontory line on lateral film. At 2-year or greater follow-up, the unfused lumbar curve remained equal to or less than the corrected thoracic curve in 63 patients (94%). No patient required extension of fusion. Frontal plane balance analysis showed that 47 of the 67 patients had the T1 plumb line within 2 cm of the midline for an average decompensation of 8.7 mm. In no patient was the loss of balance greater than 3.8 cm. Sagittal plane balance analysis showed that only one patient had inferior junctional kyphosis greater than 10 degrees. This did not require extension of fusion. There were no cases of superior junctional kyphosis. The concept of selective thoracic fusion in the King II curve pattern appears to be valid. These findings suggest that arthrodesis of the lumbar spine can be avoided when this pattern is properly diagnosed and appropriately treated. Proper identification of the stable and neutral vertebra and of the appropriate level of fusion are important to achieve good postoperative balance. Successful preservation of lumbar motion segments is important to long-term satisfactory outcome in adolescent idiopathic scoliosis.
Article
A comparative evaluation of supine right and left lateral-bending radiographs and push-prone radiographs in patients with thoracolumbar and lumbar scoliosis to determine postoperative correction of the curve. To determine the difference in the ability of the push-prone radiograph and the supine lateral-bending radiograph to predict postoperative coronal alignment for primary thoracolumbar and lumbar curves managed with an anterior spinal instrumentation and fusion. Right and left supine side-bending radiographs are the standard means of evaluating curve flexibility before surgery in idiopathic scoliosis. A push-prone radiograph also has been obtained at the authors' institution as a single dynamic radiographic assessment of forced correction of the primary curve and resultant effects on compensatory curves above and below the fusion. Preoperative standing, supine right and left lateral-bending, and push-prone radiographs were performed in 40 patients who underwent anterior spinal instrumentation and fusion. Postoperative standing radiographs of the spine were obtained at 3 months after surgery. Measurements on all the radiographs included the coronal Cobb angle, the angle of the lowest instrumented vertebra to the horizontal, the rotation of the lowest instrumented vertebra, and the distance of the midpoint of the lowest instrumented vertebra from the center sacral line. The lateral-bending and the push-prone radiographs predicted less correction of the Cobb angle and the angle of the lowest instrumented vertebra to the horizontal than was achieved after surgery. However, the push-prone radiograph was superior to the lateral-bending radiograph in accurately predicting the postoperative correction of the rotation of the lowest instrumented vertebra as well as the translation of the lowest instrumented vertebra from the center sacral line. The push-prone and lateral-bending radiographs are similar in predicting less correction of the Cobb angle after anterior spinal surgery. The push-prone radiograph helps in determining the effects that correction of the primary curve has on the curves above and below the level of fusion by better predicting the translational correction of the lowest instrumented vertebra and the rotation of the lowest instrumented vertebra.
Article
A prospective evaluation of radiographs in patients undergoing anterior spinal fusion or posterior spinal fusion for adolescent idiopathic scoliosis. To determine the most effective preoperative radiographic method for evaluating coronal plane flexibility by comparing preoperative and postoperative correction. Curve flexibility is traditionally evaluated with side-bending radiographs. Recently, the fulcrum-bending radiograph was shown to provide better correction of thoracic curves undergoing posterior spinal fusion but was not evaluated in thoracolumbar/lumbar curves or in patients undergoing anterior spinal fusion. Preoperative coronal radiographs of 46 consecutive patients undergoing spinal fusion for adolescent idiopathic scoliosis obtained while standing, lying supine, side-bending (maximally bending while supine), push-prone (padded bolsters applied to chest wall while prone), and fulcrum-bending (curve apex suspended over a radiolucent fulcrum while lateral) were compared with standing postoperative radiographs. Cobb angles were determined and evaluated for statistical significance. The fulcrum-bending radiograph demonstrated statistically better correction than other preoperative methods for main thoracic curves (P < 0.01) but fell short of demonstrating the correction obtained surgically. There was no statistical difference between side-bending, fulcrum-bending, or postoperative correction for thoracolumbar/lumbar curves (all P values > 0.07). The left side-bending was the most effective method for reducing upper thoracic curves (P < 0.001). There was no difference in the results obtained for curves corrected by anterior spinal fusion or anterior spinal fusion. To achieve maximal preoperative correction, thoracic fulcrum-bending radiographs should be obtained for evaluating main thoracic curves, whereas side-bending radiographs should continue to be used for evaluating both upper thoracic and thoracolumbar/lumbar curves.
Article
The lack of a reliable, universally acceptable system for classification of adolescent idiopathic scoliosis has made comparisons between various types of operative treatment an impossible task. Furthermore, long-term outcomes cannot be determined because of the great variations in the description of study groups. We developed a new classification system with three components: curve type (1 through 6), a lumbar spine modifier (A, B, or C), and a sagittal thoracic modifier (-, N, or +). The six curve types have specific characteristics, on coronal and sagittal radiographs, that differentiate structural and nonstructural curves in the proximal thoracic, main thoracic, and thoracolumbar/lumbar regions. The lumbar spine modifier is based on the relationship of the center sacral vertical line to the apex of the lumbar curve, and the sagittal thoracic modifier is based on the sagittal curve measurement from the fifth to the twelfth thoracic level. A minus sign represents a curve of less than +10 degrees, N represents a curve of 10 degrees to 40 degrees, and a plus sign represents a curve of more than +40 degrees. Five surgeons, members of the Scoliosis Research Society who had developed the new system and who had previously tested the reliability of the King classification on radiographs of twenty-seven patients, measured the same radiographs (standing coronal and lateral as well as supine side-bending views) to test the reliability of the new classification. A randomly chosen independent group of seven surgeons, also members of the Scoliosis Research Society, tested the reliability and validity of the classification as well. The interobserver and intraobserver kappa values for the curve type were, respectively, 0.92 and 0.83 for the five developers of the system and 0.740 and 0.893 for the independent group of seven scoliosis surgeons. In the independent group, the mean interobserver and intraobserver kappa values were 0.800 and 0.840 for the lumbar modifier and 0.938 and 0.970 for the sagittal thoracic modifier. These kappa values were all in the good-to-excellent range (>0.75), except for the interobserver reliability of the independent group for the curve type (kappa = 0.74), which fell just below this level. This new two-dimensional classification of adolescent idiopathic scoliosis, as tested by two groups of surgeons, was shown to be much more reliable than the King system. Additional studies are necessary to determine the versatility, reliability, and accuracy of the classification for defining the vertebrae to be included in an arthrodesis.