Publications (10)18.36 Total impact
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Article: Accuracy of free-hand placement of thoracic pedicle screws in adolescent idiopathic scoliosis: how much of a difference does surgeon experience make?
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ABSTRACT: The use of thoracic pedicle screws for the treatment of adolescent idiopathic scoliosis (AIS) has gained widespread popularity. However, the placement of pedicle screws in the deformed spine poses unique challenges, and surgeons experience a learning curve. The in vivo accuracy as determined by computed tomography (CT) of placement of thoracic pedicle screws in the deformed spine as a function of surgeon experience is unknown. We undertook a retrospective review to determine the effect of surgeon experience on the accuracy of thoracic pedicle screw placement in AIS. In 2005, we started to obtain routine postoperative CT scans on patients undergoing a spinal fusion. From a database of these patients, we selected AIS patients, who underwent a posterior spinal fusion. Fifteen consecutive patients for each of the following three groups stratified by attending surgeon experience were selected (N=45): A) less than 20 cases of all pedicle screw constructs for AIS (surgeons <2years of practice), B) 20–50 cases (surgeons 2–5years of practice), and C) greater than 50 cases (surgeons greater than 5years of practice). Intraoperative evaluation of all screws included probing of the pedicle screw tract, neurophysiologic monitoring, and fluoroscopic confirmation. A total of 856 thoracic pedicle screws were studied. Postoperative CT scans were evaluated by two spine surgeons and a consensus read established as follows: (1) In: intraosseous placement or ≤2-mm breach, (2) Out: >2-mm breach, either medial or lateral. Of the 856 screws, 104 demonstrated a >2-mm breach, for an overall rate of 12.1% (medial=55, lateral=49, P=0.67). When the breach rates were stratified by surgeon experience, there was a trend toward decreased rate of breach for the most experienced surgeons, although this did not attain statistical significance (Group A: 12.7%, Group B: 12.9%, Group C: 10.8%, P=0.58). However, the most experienced group (C) had a markedly decreased rate of medial breaches (3.5 vs. 7.4% and 8.4% for groups A and B, respectively, P<0.01). The breach rate for the concave periapical screws was not statistically different from the overall breach rate (13.0% vs. 12.1%, P=0.93). In conclusion, the overall accuracy of placement of pedicle screws in the deformed spine was 87.9%, with no neurologic, vascular, or visceral complications. Meticulous technique allows spine surgeons with a range of surgical experience to accurately and safely place thoracic pedicle screws in the deformed spine. The most experienced surgeons demonstrated the lowest rate of medial breaches.European Spine Journal 04/2012; 19(1):91-95. · 1.97 Impact Factor -
Article: Triggered electromyography for placement of thoracic pedicle screws: is it reliable?
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ABSTRACT: Reliable electromyography (EMG) thresholds for detecting medial breaches in the thoracic spine are lacking, and there is a paucity of reports evaluating this modality in patients with adolescent idiopathic scoliosis (AIS). This retrospective analysis evaluates the ability of triggered EMG to detect medial breaches with thoracic pedicle screws in patients with AIS. We reviewed 50 patients (937 pedicle screws) undergoing posterior spinal fusion (PSF) with intraoperative EMG testing. Postoperative CT scans were used for breach identification, and EMG values were analyzed. There were 47 medial breaches noted with a mean threshold stimulus of 10.2 mA (milliamperes). Only 8/47 breaches stimulated at 2-6 mA. Thirteen of the forty-seven screws tested at an EMG value ≤6 mA and/or a decrease of ≥65% compared with intraosseously placed screws. The sensitivity and positive predictive value for EMG was 0.28 and 0.21. A subanalysis of T10-T12 screws identified six of seven medial breaches. Using guidelines from the current literature, EMG does not appear to be reliable in detecting medial breaches from T2 to T9 but may have some utility from T10 to T12.European Spine Journal 06/2011; 20(6):869-74. · 1.97 Impact Factor -
Article: Learning curve for placement of thoracic pedicle screws in the deformed spine.
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ABSTRACT: The placement of thoracic pedicle screws, particularly in the deformed spine, poses unique challenges, and a learning curve. We measured the in vivo accuracy of placement of thoracic pedicle screws by computed tomography in the deformed spine by a single surgeon over time. After obtaining institutional review board approval, we retrospectively selected the first 30 consecutive patients who had undergone a posterior spinal fusion using a pedicle screw construct for adolescent idiopathic scoliosis by a single surgeon. The average patient age was 14 years, and their preoperative thoracic Cobb angle was, on average, 62.6 degrees. Patients were divided into 3 groups: group A, patients 1 to 10; group B, patients 11 to 20; and group C, patients 21 to 30. Intraoperative evaluation of all pedicle screws included probing of the pedicle screw tract, neurophysiologic monitoring, and fluoroscopic confirmation. Postoperative computed tomographic scans were evaluated by 2 spine surgeons, and a consensus read was established, as previously described (Kim YJ, Lenke LG, Bridwell KH, Cho YS, Riew KD. Free hand pedicle screw placement in the thoracic spine: is it safe? Spine. 2004;29(3):333-342), as (1) "in," axis of pedicle screw within the confines of the pedicle; or (2) "out," axis of pedicle screw outside the confines of the pedicle. A total of 553 thoracic pedicle screws were studied (group A, n = 181; group B, n = 189; group C, n = 183) with 64 graded as out (medial, 35; lateral, 29), for an overall breach rate of 11.6%. When the breach rates were stratified by the surgeon's evolving experience, there was a temporal decrease in the breach rate (group A, 15.5%; group B, 10.6%; group C, 8.7%; P < .05). This decreased breach rate was reflected in fewer medial breaches over time (group A, 9.4%; group B, 5.8%; group C, 3.8%; P < .05). Similar trends were observed for the concave periapical screws, although statistical significance was not attained (group A, 21.2%; group B, 16.2%; group C, 10.5%). The overall accuracy of placement of thoracic pedicle screws in the deformed spine was 88.4%, with no neurologic or visceral complications. One patient from group A returned to the operating room on postoperative day 2 for removal of an asymptomatic left T7 thoracic pedicle screw abutting the aorta. As surgeon experience increased, there was an overall decreased breach rate, which was mainly reflected in fewer medial breaches.Neurosurgery 02/2010; 66(2):290-4; discussion 294-5. · 2.79 Impact Factor -
Article: Vertebral body stapling: a fusionless treatment option for a growing child with moderate idiopathic scoliosis.
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ABSTRACT: Retrospective review. To report the results of vertebral body stapling (VBS) with minimum 2-year follow-up in patients with idiopathic scoliosis. While bracing for idiopathic scoliosis is moderately successful, its efficacy has been called into question, and it carries associated psychosocial ramifications. VBS has been shown to be a safe, feasible alternative to bracing for idiopathic scoliosis. We retrospectively reviewed 28 of 29 patients (96%) with idiopathic scoliosis treated with VBS followed for a minimum of 2 years. Inclusion criteria: Risser sign of 0 or 1 and coronal curve measuring between 20 degrees and 45 degrees . There were 26 thoracic and 15 lumbar curves. Average follow-up was 3.2 years. The procedure was considered a success if curves corrected to within 10 degrees of preoperative measurement or decreased >10 degrees . Thoracic curves measuring <35 degrees had a success rate of 77.7%. Curves which reached < or =20 degrees on first erect radiograph had a success rate of 85.7%. Flexible curves >50% correction on bend film had a success rate of 71.4%. Of the 26 curves, 4 (15%) showed correction >10 degrees. Kyphosis improved in 7 patients with preoperative hypokyphosis (<10 degrees of kyphosis T5-T12). Of the patients, 83.5% had remaining normal thoracic kyphosis of 10 degrees to 40 degrees. Lumbar curves demonstrated a success rate of 86.7%. Four of the 15 lumbar curves (27%) showed correction >10 degrees. Major complications include rupture of a unrecognized congenital diaphragmatic hernia and curve overcorrection in 1 patient. Two minor complications included superior mesenteric artery syndrome and atelectasis due to a mucous plug. There were no instances of staple dislodgement or neurovascular injury. Analysis of patients with idiopathic scoliosis (IS) with high-risk progression treated with vertebral body stapling (VBS) and minimum 2-year follow-up shows a success rate of 87% in all lumbar curves and in 79% of thoracic curves <35 degrees. Thoracic curves >35 degrees were not successful and require alternative treatments.Spine 01/2010; 35(2):169-76. · 2.08 Impact Factor -
Article: Feasibility and accuracy of pedicle screws in children younger than eight years of age.
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ABSTRACT: STUDY DESIGN.: A retrospective review. OBJECTIVE.: To determine the feasibility and accuracy of pedicle screw placement in children younger than 8 years of age. SUMMARY OF BACKGROUND DATA.: Computed tomography (CT) scanning is commonly used for assessing the breach associated with pedicle screw placement. The accuracy of pedicle screw placement as evaluated by CT has been described for adults and older children. No study has been published describing pedicle screw breach rate as evaluated by CT scanning in children younger than 8 years of age. METHODS.: A retrospective review of 16 children, with an average age of 4 years 7 months (range, 2 years 3 months to 7 years 11 months) with insertion of 88 pedicle screws was performed. These patients underwent postoperative CT scan. Breach rate was assessed using previously described criteria by Kim et al in 2005. RESULTS.: No patient experienced neurologic, vascular, or visceral complications. There were 88 screws (30 thoracic and 58 lumbar) available for CT evaluation. The overall accuracy was 93.2% with 1 medial breach and 5 lateral breaches. The median screw diameter was 4.5 mm (range, 3.5-5.5 mm) for the thoracic spine and 5.5 mm (range, 4-6 mm) for the lumbar spine. CONCLUSION.: The results suggest that pedicle screws can be safely and accurately placed in young children. The overall accuracy of acceptable pedicle screw placement was 93.2% in patients younger than 8 years of age. Screw diameters ranging from 3.5 to 5.5 mm (for the thoracic spine) and 4 to 6 mm (for the lumbar spine) can be safely used in this population.Spine 12/2009; 34(26):2907-11. · 2.08 Impact Factor -
Article: An unusual case of congenital scoliosis in a patient with Down syndrome.
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ABSTRACT: We report on a case of a young infant with congenital scoliosis (multiple hemivertebrae in the thoracic region and an unsegmented bar in the mid-thoracic region) associated with Down syndrome. Although scoliosis has been previously described in relation to Down syndrome, to the best of our knowledge, there has been no prior report of Down syndrome associated with congenital scoliosis. The patient underwent placement of a vertical expandable prosthetic titanium rib implant. He tolerated the procedure well and had no complications. This case highlights that vertebral malformation may be an etiology of scoliosis in Down syndrome.Journal of pediatric orthopaedics. Part B / European Paediatric Orthopaedic Society, Pediatric Orthopaedic Society of North America 10/2009; 18(6):365-8. · 0.66 Impact Factor -
Article: The role of bracing, casting, and vertical expandable prosthetic titanium rib for the treatment of infantile idiopathic scoliosis: a single-institution experience with 31 consecutive patients. Clinical article.
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ABSTRACT: There are few data on treatment results for patients with idiopathic infantile scoliosis (IIS). Thus, the authors have performed a retrospective review of their experience with treating these patients, particularly as newer technologies, such as the vertical expandable prosthetic titanium rib (VEPTR), emerge. This retrospective study was conducted to evaluate the methods of treatment used to manage IIS at a single institution. The authors reviewed 31 consecutive patients with a primary diagnosis of IIS. Patients were screened to ensure that there were no confounding congenital anomalies or comorbidities that may have contributed to the spinal deformity. The average age at the time of initial treatment was 25 months. Treatment modalities included bracing, serial body casting, and VEPTR. Pretreatment, posttreatment, and most recent Cobb angles were compared to assess the overall curve correction, and patient charts were reviewed for the occurrence of complications. Of the 31 patients, 17 were treated with a brace, 9 of whom had curve progression and went on to other forms of treatment. Of the 8 who did respond, there was an overall improvement of 51.2%. The 10 patients who received body casts, who had a mean preoperative Cobb angle of 50.4 degrees, demonstrated an average correction of 59.0%, with only a few skin irritations reported. The 10 patients treated with VEPTR devices demonstrated a mean preoperative Cobb angle of 90.0 degrees, and an average correction of 33.8% was attained. Three of the VEPTR-treated patients (33%) experienced minor problems. The authors' results suggest that body casting has utility for appropriately selected patients; that is, those with smaller, flexible spinal curves. Bracing had limited utility, with high levels of progression and the need for secondary treatments. The VEPTR device appears to be a viable alternative for large-magnitude curves.Journal of Neurosurgery Spine 08/2009; 11(1):3-8. · 1.53 Impact Factor -
Article: Bilateral use of the vertical expandable prosthetic titanium rib attached to the pelvis: a novel treatment for scoliosis in the growing spine.
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ABSTRACT: Few options exist for the treatment of severe, early onset scoliosis. Goals of treatment include stabilizing curve progression while allowing for normal spine, chest, and lung growth. The vertical expandable prosthetic titanium rib (VEPTR) is a novel device designed to control the spine deformity while permitting lung and spine growth. In this paper the authors report their experience with using bilateral VEPTRs from the ribs to the pelvis for children with severe, early onset scoliosis. Eleven children were identified who had been treated with bilateral VEPTRs from the ribs to the pelvis. The authors conducted a retrospective review and collected the following data: clinical diagnosis, age at surgery, number of lengthening procedures, and complications. In addition, pre- and postoperative radiographs were reviewed to measure maximum Cobb angle (both thoracic and lumbar), thoracic height, total spine height as measured from T-1 to S-1, thoracic kyphosis (T2-12), and lumbar lordosis (L1-S1). The average patient age at surgery was 71 months; the mean preoperative thoracic Cobb angle was 81.7 degrees . This angle was corrected to 50.6 degrees immediately postoperatively, and this correction was maintained; at the most recent follow-up the curves averaged 58 degrees . Similarly, the preoperative kyphosis (T2-12) angle measured 43 degrees preoperatively, 23 degrees immediately postoperatively, and 37 degrees at the most recent follow-up evaluation. The patients underwent a total of 41 lengthening procedures (average 3.7 lengthening procedures per patient), and overall spine length increased from 23.1 cm preoperatively, to 27.3 cm immediately postoperatively, to 29.4 cm at the final follow-up (an average of 25 months). Four (36.4%) of the 11 patients experienced complications. The VEPTR offers a viable treatment option for children with severe, early onset scoliosis. It achieves and maintains spinal deformity correction, while allowing for continued spine and chest-wall growth. Complication rates are similar to those reported for other growing systems.Journal of Neurosurgery Spine 05/2009; 10(4):287-92. · 1.53 Impact Factor -
Article: Acetabular changes in coxa vara.
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ABSTRACT: The purpose of this study was to define the acetabular changes associated with coxa vara and determine how these acetabuli differ from those of a normal hip. Charts and radiographs of 33 patients with coxa vara with a mean age of 6 years (range, 2-15 years) were retrospectively reviewed. The diagnosis was developmental coxa vara in 21 patients and congenital femoral deficiency in 12. Radiographic measurements, including acetabular index, sourcil slope, center edge angle, migration index, and medial joint space, were compared with those of 29 hips in the control group. The inclination of the acetabulum or acetabular slope (as measured by the acetabular index and sourcil slope) was significantly increased in the hips with coxa vara as compared with those in the control group. Both parameters have a statistically significant inverse correlation with the degree of varus, ie, the greater the varus of the proximal femur, the greater the upsloping of the acetabulum. Joint subluxation, as measured by the center edge angle, migration index, and medial joint space, showed little difference from that of control subjects. LEVEL OF EVIDENCE: Level III, diagnostic study.Clinical Orthopaedics and Related Research 08/2008; 466(7):1688-91. · 2.53 Impact Factor -
Article: Angular deformity in pediatric transtibial amputation stumps.
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ABSTRACT: Progressive angular deformity after surgical transtibial amputation in the pediatric population has not been described in the literature. Angular deformity in amputation stumps may lead to problems with pain and fitting of the prosthesis. The aim of this study was to evaluate the incidence and pattern of angular deformity and its treatment. A retrospective review of 21 patients (24 limbs) with transtibial amputation was carried out. The mean age was 7.4 years (range: 1 to 18). There were 8 congenital and 13 acquired amputations (7 trauma, 4 infection, 1 tumor, 1 vascular). Sequential radiographs were evaluated for frontal and sagittal plane alignment. Deformity was defined as an angular deviation greater than 5 degrees. Angular deformity was identified in 8 (38%) patients. Two patients had valgus deformity, 2 had varus deformity, and 1 had isolated recurvatum deformity. One patient had valgus procurvatum and 1 patient had varus recurvatum deformity. There was a mean stump revision rate of 1.38 in the congenital group and 0.85 in the acquired group. Three patients underwent deformity correction using an external fixator owing to difficulty with prosthetic fitting. All patients experienced improved fitting of their prosthesis after surgery. Angular deformity can arise in children with transtibial amputations and may influence prosthesis fit and gait. Clinical and radiographic surveillance is important, and surgical correction may be of benefit. Surprisingly, stump revision rate was similar in both groups.Journal of pediatric orthopedics 29(7):726-9. · 1.23 Impact Factor
Top co-authors
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Institutions
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2008–2012
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Shriners Hospitals for Children
Tampa, FL, USA
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2009
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University of Arkansas at Little Rock
Little Rock, AR, USA
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