Article

Spinal kyphosis causes demyelination and neuronal loss in the spinal cord: a new model of kyphotic deformity using juvenile Japanese small game fowls

December 2005
Spine 30(21):2388-92

Source
PubMed

Authors:

Keio University

Histologic changes in the spinal cord caused by progressive spinal kyphosis were assessed using a new animal model. To evaluate the effects of chronic compression associated with kyphotic deformity of the cervical spine on the spinal cord. The spinal cord has remarkable ability to resist chronic compression, however, delayed paralysis is sometimes seen following the development of spinal kyphosis. In the past, no animal model to clarify the mechanism of spinal cord damage due to spinal kyphotic deformity has been available. Laminectomy and bilateral facetectomy at the C4-C5 level was performed in 52 Japanese small game fowls. Histologic changes in the spinal cord associated with progressive kyphotic deformity were examined at different time points after surgery in each animal. The degree of spinal cord flattening and the severity of demyelination in histologic sections were quantitatively evaluated using an image analyzer, and their association with the kyphotic angle was analyzed. Changes in the microvascular distribution in the spinal cord were also examined by microangiography. In all operated animals, progressive kyphosis developed reproducibly. The kyphotic angle increased gradually until 3 weeks after surgery and stabilized thereafter. There was a significant correlation between the kyphotic angle and the degree of spinal cord flattening. The spinal cord was compressed most intensely at the apex of the kyphosis, where demyelination of the anterior funiculus as well as neuronal loss and atrophy of the anterior horn were observed. Demyelination progressed as the kyphotic deformity became more severe, initially affecting the anterior funiculus and later extending to the lateral and then the posterior funiculus. Angiography revealed a decrease of the vascular distribution at the ventral side of the compressed spinal cord. Progressive kyphosis of the cervical spine resulted in demyelination of nerve fibers in the funiculi and neuronal loss in the anterior horn due tochronic compression of the spinal cord. These histologic changes seem to be associated with both continuous mechanical compression and vascular changes in the spinal cord.

Using Electrical Stimulation of the Ulnar Nerve Trunk to Predict Postoperative Improvement in Hand Clumsiness in Patients With Cervical Spondylotic Myelopathy

Article

Nov 2022
SPINE

Study design: A prospective cohort study. Objective: To investigate whether the immediate and short-term effects of preoperative electrical peripheral nerve stimulation (ePNS) on performance of the 10-s test could predict the early postoperative outcomes of patients with cervical spondylotic myelopathy (CSM). Summary of background data: Previous studies have shown that early clinical improvement in CSM patients may be due to reversal of spinal cord ischemia followwing from spinal cord compression. Methods: We conducted a 10-s test before surgery, after ePNS, and at discharge (1 wk after surgery) in 44 patients with CSM who underwent C3-7 laminoplasty and evaluated their correlations. The effects of the procedures (ePNS or operation) and sides (stimulated or non-stimulated side) for the 10-s test were analyzed using repeated measures analysis of variance (ANOVA). The Pearson correlation coefficient was used to measure the relationship between the 10-s test values according to the method (after ePNS vs. surgery). In addition, the Bland-Altman method was used to evaluate the degree of agreement between the 10-s test obtained after ePNS versus shortly after surgery. Results: The preoperative 10-s test showed the most improvement immediately after administration of ePNS, with a gradual decrease for the first 30 minutes following completion. After the inital 30 minutes, performance decreased rapidly, and by 60 minutes performance essentially returned to baseline. The 10-s post-ePNS had a strong positive correlation with the 10-s test in the early postoperative period (at discharge=1 wk after surgery). These phenomena were observed with the left hand, the side stimulated with ePNS, as well as the right hand, the side not stimulated. Conclusion: Early postoperative outcomes after CSM surgery may be predicted by the results of pre-operative ePNS. Level of evidence: 3.

Sagittal balance of the cervical spine

Article

Full-text available

Sep 2021

The treatment of adult cervical deformity continues to be complex with high complication rates. However there are many new advancements and overall patients do well following surgical correction. To date there are now many types of cervical deformity that have been classified and there exists a variety of surgical options. These recent advances have been developed in the last few years and the field continues to grow at a rapid rate. Thus, the goal of this article is to provide an updated review of cervical sagittal balance including; cervical alignment parameters, deformity classification, clinical evaluation, with both conservative and surgical treatment options.

Alignment, Classification, Clinical Evaluation, and Surgical Treatment for Adult Cervical Deformity: A Complete Guide

Article

Feb 2021
NEUROSURGERY

Adult cervical deformity management is complex and is a growing field with many recent advancements. The cervical spine functions to maintain the position of the head and plays a pivotal role in influencing subjacent global spinal alignment and pelvic tilt as compensatory changes occur to maintain horizontal gaze. There are various types of cervical deformity and a variety of surgical options available. The major advancements in the management of cervical deformity have only been around for a few years and continue to evolve. Therefore, the goal of this article is to provide a comprehensive review of cervical alignment parameters, deformity classification, clinical evaluation, and surgical treatment of adult cervical deformity. The information presented here may be used as a guide for proper preoperative evaluation and surgical treatment in the adult cervical deformity patient.

Spinal cord demyelination predicts neurological deterioration in patients with mild degenerative cervical myelopathy

Article

Full-text available

Jan 2025

Background Degenerative cervical myelopathy (DCM) is the most common form of atraumatic spinal cord injury globally. Clinical guidelines regarding surgery for patients with mild DCM and minimal symptoms remain uncertain. This study aims to identify imaging and clinical predictors of neurological deterioration in mild DCM and explore pathophysiological correlates to guide clinical decision-making. Methods Patients with mild DCM underwent advanced MRI scans that included T2-weighted, diffusion tensor imaging and magnetisation transfer (MT) sequences, along with clinical outcome measures at baseline and 6-month intervals after enrolment. Quantitative MRI (qMRI) metrics were derived above and below maximally compressed cervical levels (MCCLs). Various machine learning (ML) models were trained to predict 6 month neurological deterioration, followed by global and local model interpretation to assess feature importance. Results A total of 49 patients were followed for a maximum of 2 years, contributing 110 6-month data entries. Neurological deterioration occurred in 38% of cases. The best-performing ML model, combining clinical and qMRI metrics, achieved a balanced accuracy of 83%, and an area under curve-receiver operating characteristic of 0.87. Key predictors included MT ratio (demyelination) above the MCCL in the dorsal and ventral funiculi and moderate tingling in the arm, shoulder or hand. qMRI metrics significantly improved predictive performance compared to models using only clinical (bal. acc=68.1%) or imaging data (bal. acc=57.4%). Conclusions Reduced myelin content in the dorsal and ventral funiculi above the site of compression, combined with sensory deficits in the hands and gait/balance disturbances, predicts 6-month neurological deterioration in mild DCM and may warrant early surgical intervention.

Comparing Combined Anterior and Posterior to Posterior-Only Decompression and Fusion Crossing the Cervico-Thoracic Junction in Octogenarians

Article

Full-text available

Mar 2021

Study Design Retrospective cohort study. Objective The purpose of the study was to compare early complication, morbidity and mortality risks associated with fusion surgery crossing the cervico-thoracic junction in patients aged over 80 years undergoing combined anterior and posterior approach versus a posterior-only approach. Methods We retrospectively identified octogenarian patients with myelopathy who underwent fusion crossing the cervico-thoracic junction. Patient demographics, Nurick score, surgical characteristics, complications, hospital course, early outcome and 90-day mortality were collected. Comorbidities were classified using the age-adjusted Charlson Comorbidity Index (AACCI). Radiographic measurements for deformity correction included the C2-C7 sagittal Cobb angle, C2-7 sagittal vertical axis and T1 slope pre- and postoperatively. Results Out of 8,521 surgically treated patients, 12 octogenarian patients had a combined anterior and posterior approach (AP group) and 14 were treated from posterior-only (P group). Mean age was 81.4 ± 1.2 and 82.5 ± 2.7 years, respectively. There was no significant difference in Nurick scores between the groups ( P > 0.05). The major complication risk in the AP group was significantly higher, requiring PEG tube placement due to severe dysphagia in 4 patients (33%) compared to none in the P group. A greater improvement in cervical lordosis could be achieved through a combined approach. The 90-day mortality risk was 8% for the AP group and 0% for the P group. Conclusions A combined anterior and posterior approach is associated with a significantly higher major complication rate and can result in severe dysphagia requiring PEG tube placement in one-third of patients over 80 years of age.

Radiological outcomes following hyperlordotic cage insertion in anterior cervical discectomy and fusion

Article

Dec 2019

Background: Cervical alignment is associated with myelopathy and quality of life. Anterior cervical discectomy and fusion (ACDF) aims to decompress neural structures and optimise cervical alignment. This study examines the quantitative impact of the hyperlordotic 15° ACDF cage on cervical alignment, and compares it to that of the standard lordosis cage. Methods: A retrospective analysis of radiographical parameters of cervical alignment was conducted in 80 consecutive ACDF patients from two institutions between 2013 and 2017. Forty received 15° cages, 40 received standard cages. Pre- and post-operative Cobb angles and sagittal vertical axes (SVA) were generated from radiographical imaging utilising the SurgimapTM program. Changes in lordosis and SVA were compared within and between groups, and the significance of the change evaluated using the Student t-test. Results: In both groups, post-operative device level, segmental, and global Cobb angles were superior to preoperative values (P<0.05), especially among patients with preoperative kyphosis (P<0.05). Trends suggested greater changes in lordosis in the 15° group, but they did not reach statistical significance (P=0.06-0.23). However, subgroup analyses indicated greater device level Cobb angle change in patients less than 65 yo (P=0.049), and those with preoperative lordosis (P=0.003). Neither standard nor hyperlordotic cages significantly improved SVA in this study. Conclusions: Hyperlordotic and standard cages both improve cervical lordosis segmentally and globally. Hyperlordotic cages were not shown to be statistically superior to standard cages in this study. Prospective studies featuring consistent imaging modalities are necessary to further delineate their utility.

Evaluation and Treatment of Cervical Spine Deformity

Chapter

Full-text available

Jul 2024

The cervical spine plays a pivotal role in activities of daily living by allowing a wide range of motion while supporting the cranium. Cervical spine deformity (CSD) can cause significant negative impact on the patient’s functional status and quality of life. Surgical correction of cervical spine deformity can be challenging due to the complexity of the regional neurovascular anatomy, which necessitates a comprehensive understanding of the cervical spine anatomy and biomechanics. Goals of cervical deformity surgery include decompression of neural elements, and restoration of cervical alignment, and achieving solid arthrodesis. Cervical spine deformity correction can involve various anterior and posterior surgical techniques. Careful surgical planning and meticulous surgical techniques are essential to minimize complications and optimize clinical outcomes in cervical deformity correction. In this chapter, we provide an in depth review of pre-operative evaluation, surgical planning, and treatment strategies for cervical spine deformity.

Cervical Spine Alignment; Observation Over a Ten-Year Period Using Measurement of Cobb Angle and a Modified Pfirrmann Grade

Article

May 2024

Background and Aim: We sought to explore whether or not this excessive use of smart technology may be associated with a generational change in the cervical spine over time. Methods and Results: All those patients who underwent cervical spine MRI aged 15 to 30 years over the years June 2007 to 2008 and June 2017 to 2018 were considered for evaluation. Each patient had measurement of their Cobb angle and a modified Pfirrmann grade. 217 patients - 83 (2007-2008) and 134 (2017-2018) were evaluated. There was no difference in cervical alignment over time, but males tended to have a greater lordosis(p<0.001). Using the modified Pfirrmann grading system a difference over time was noted most noticeable at C2/3 (p=0.004); C3/4 (p=0.019 and C7/8 (p=0.003). Conclusion: There was no change in the structural integrity of the cervical spine between the two groups over time. A worsening degenerative disease without a structural change was observed, an effect was more apparent in the males.

Does Focal Kyphotic Deformity at Non‐responsible Levels Affect the Outcomes of Anterior Cervical Decompression and Fusion?

Article

Full-text available

May 2024

Objective Focal cervical kyphotic deformity (FCK) without neurologic compression is not uncommon in patients with cervical spondylotic myelopathy (CSM) who underwent anterior cervical decompression and fusion (ACDF) surgery. It remains unclear whether FCK at non‐responsible levels needs to be treated simultaneously. This study aims to investigate whether FCK at non‐responsible levels is the prognostic factor for CSM and elucidate the surgical indication for FCK. Methods Patients with CSM who underwent ACDF between January 2016 and April 2021 were included. Patients were divided into two groups according to the presence of FCK and two classifications according to global cervical sagittal alignment. Clinical outcomes were compared using Japanese Orthopaedic Association (JOA) scores and recovery rate (RR) of neurologic function. Univariate and multivariate analysis based on RR assessed the relationship between various possible prognostic factors and clinical outcomes. The receiver operating characteristic curve (ROC) was used to determine the optimal cutoff value of the focal Cobb angle to predict poor clinical outcomes. Results A total of 94 patients were included, 41 with FCK and 53 without. Overall, the RR of neurologic function was significantly lower in the FCK than in the non‐FCK group. Further analysis showed that the RR difference between the two groups was only observed in hypo‐lordosis classification (kyphotic and sigmoid alignment), but not in the lordosis classification. Multivariate analysis showed that the preoperative focal Cobb angle in the FCK level (OR = 0.42; 95% CI = 0.18–0.97) was independently associated with clinical outcomes in the hypo‐lordosis classification. The optimal cutoff point of the preoperative focal kyphotic Cobb angle was calculated at 4.05°. Conclusion For CSM with hypo‐lordosis, FCK was a risk factor for poor postoperative outcomes. Surgeons may consider treating the FCK simultaneously if the focal kyphotic Cobb angle of FCK is greater than 4.05° and is accompanied by cervical global kyphotic or sigmoid deformity.

Potential impairment of spinal cord around the apical vertebral level in hyperkyphotic patients: findings from diffusion tensor imaging

Article

Full-text available

Feb 2024
EUR SPINE J

Purpose To evaluate the neuronal metrics/microstructure of the spinal cord around apical region in patients with hyperkyphosis using diffusion tensor imaging (DTI). Methods Thirty-seven patients with hyperkyphosis aged 45.5 ± 19.6 years old who underwent 3.0 T magnetic resonance imaging (MRI) examination with DTI sequence were prospectively enrolled from July 2022 to July 2023. Patients were divided into three groups according to spinal cord/ cerebrospinal fluid (CSF) architecture on sagittal-T2 MRI of the thoracic apex (the axial spinal cord classification): Group A—circular cord with visible CSF, Group B—circular cord without visible CSF at apical dorsal, and Group C—spinal cord deformed without intervening CSF. The fractional anisotropy (FA) values acquired from DTI were compared among different groups. Correlations between DTI parameters and global kyphosis (GK)/sagittal deformity angular ratio (sagittal DAR) were evaluated using Pearson correlation coefficients. Results In all patients, FA values were significantly lower at apical level as compared with those at one level above or below the apex (0.548 ± 0.070 vs. 0.627 ± 0.056 versus 0.624 ± 0.039, P < 0.001). At the apical level, FA values were significantly lower in Group C than those in Group B (0.501 ± 0.052 vs. 0.598 ± 0.061, P < 0.001) and Group A (0.501 ± 0.052 vs. 0.597 ± 0.019, P < 0.001). Moreover, FA values were significantly lower in symptomatic group than those in non-symptomatic group (0.498 ± 0.049 v. 0.578 ± 0.065, P < 0.001). Pearson correlation analysis showed that GK (r² = 0.3945, P < 0.001) and sagittal DAR (r² = 0.3079, P < 0.001) were significantly correlation with FA values at apical level. Conclusion In patients with hyperkyphosis, the FA of spinal cord at apical level was associated with the neuronal metrics/microstructure of the spinal cord. Furthermore, the DTI parameter of FA at apical level was associated with GK and sagittal DAR. Level of evidence 4.

Preoperative Cervical Range of Motion in Flexion as a Risk Factor for Postoperative Cervical Sagittal Imbalance After Laminoplasty

Article

Full-text available

Oct 2023
SPINE

Study design: Retrospective study. Objective: To investigate factors associated with cervical sagittal imbalance after cervical laminoplasty (LMP). Summary of background data: Preoperative dynamic cervical sagittal alignment is an important predictor for changes in cervical sagittal alignment and clinical outcomes after LMP. However, the impact of preoperative dynamic cervical sagittal alignment on postoperative changes in the cervical sagittal vertical axis (cSVA) after LMP remains unclear. We hypothesized that preoperative cervical flexion and extension function are associated with the changes in cSVA and clinical outcomes and found potential risk factors for post-LMP cervical sagittal imbalance (CSI). Methods: Patients undergoing LMP at a single institution between January 2019 and December 2021 were retrospectively reviewed. The average follow-up period was 19 months. The parameters were collected before the surgery and at the final follow-up. We defined the changes in cSVA (△cSVA) ≤ -10 mm as the improvement group, -10 mm < △cSVA ≤ 10 mm as the stable group, and △cSVA > 10 mm as the deterioration group. Multivariate logistic regression was used to evaluate factors associated with postoperative CSI. The chi-square test was used to compare categorical data between groups. T-tests, ANOVA, Kruskal-Wallis tests, and Mann-Withney-Wilcoxon tests were used to assess the differences between radiographic and clinical parameters among groups. A receiver-operating characteristic curve (ROC) analysis was used to identify optimal cutoff values. Results: The study comprised 102 patients with cervical spondylotic myelopathy. The Japanese Orthopedic Association (JOA) recovery rate was better in the improvement group and a significant aggravation in neck pain was observed in the deterioration group after surgery. Cervical Flex ROM (spine range of flexion) was significantly higher in the deterioration group. The multivariate logistic regression model suggested that greater Flex ROM and starting LMP at C3 were significant risk factors for postoperative deterioration of cervical sagittal balance. Receiver operating characteristic curves showed that the cut-off value for preoperative Flex ROM was 34.10°. Conclusion: Preoperative dynamic cervical sagittal alignment influences postoperative cervical sagittal balance after LMP. Cervical LMP should be carefully considered for patients with a preoperative high Flex ROM, as cervical sagittal imbalance is likely to occur after surgery. Level of evidence: 3.

Surgical Management of Recurrent Plexiform Neurofibroma in a Pediatric Patient with Severe Cervical Kyphotic Deformity: A Case Report

Article

Oct 2023

Approximately 50% of patients with neurofibromatosis type 1 (NF1) develop orthopedic complications, and spinal deformities are common manifestations. Cervical kyphosis is comparatively rare in NF1; however, it results in spinal cord compression associated with paralysis and respiratory dysfunction, requiring surgical correction. Pediatric patients with NF1 usually have small and defective pedicles or lateral masses, and surgery with a single approach is limited to ensure sufficient spinal cord decompression and deformity correction. However, no reliable treatment guidelines are available for this challenging condition. This case report presents a 7-year-old patient with NF1 who had severe cervical kyphosis with intradural extramedullary neurofibromas. The tumors were removed before correcting the deformity to decompress the spinal cord and reduce the risk of spinal cord injury. Moreover, we effectively corrected and stabilized the kyphosis using the anterior-posterior-anterior approach.

Clinicoradiological Risk Factors Associated with Inability to Achieve Minimum Clinically Important Difference in Operated Cases of Cervical Spondylotic Myelopathy

Article

Full-text available

Jul 2023
Asian Spine J

Study design: This is a retrospective cohort study. Purpose: This study aimed to identify the clinicoradiological risk factors associated with the inability to achieve minimum clinically important difference (MCID) on the modified Japanese Orthopaedic Association (mJOA) Scale in operated cases of cervical spondylotic myelopathy (CSM). Overview of literature: Only a few studies have evaluated the outcomes of surgery performed for CSM using MCID on the mJOA scale. Methods: We analyzed 124 operated CSM cases from March 2019 to April 2021 for preoperative clinical features, cervical sagittal radiographic parameters, and magnetic resonance imaging (MRI) signal intensities (SI). The risk factors associated with missing the MCID (poor outcome) on mJOA at the final follow-up were identified using binary logistic regression. Multivariate analysis was used to find significant risk factors, and odds ratios (OR) were computed. Results: A total of 110 men (89.2%) and 14 women (10.8%) with an average age of 53.5±13.2 years were included in the analysis. During the last follow-up, 89 cases (72.1%) achieved MCID (meaningful gains following surgery) while 35 (27.9%) could not. The final model identified the following parameters as significant risk factors for poor outcome: increased duration of symptoms (OR, 6.77; p=0.001), lower preoperative mJOA scale (OR, 0.75; p=0.029), the presence of multilevel T2-weighted (T2W) MRI SI (OR, 4.79; p=0.004), and larger change in cervical sagittal vertical axis (ΔcSVA) (OR, 1.06; p=0.013). Also, an increase in cSVA postoperatively correlated with a reduced functional recovery rate (r=-0.4, p<0.001). Conclusions: Surgery for CSM leads to significant functional benefits. However, poorer outcomes are observed in cases of greater duration of symptoms, higher preoperative severity with multilevel T2W MRI SI, and a larger increase in the postoperative cSVA (sagittal imbalance).

Concepts and Techniques to Prevent Cervical Spine Deformity After Spine Surgery: A Narrative Review

Article

Full-text available

Mar 2023

Adult cervical spine deformity is associated with decreased health-related quality of life, disability, and myelopathy. A number of radiographic parameters help to characterize cervical deformity and aid in the diagnosis and treatment. There are several etiologies for cervical spine deformity, the most common being iatrogenic. Additionally, spine surgery can accelerate adjacent segment degeneration which may lead to deformity. It is therefore important for all spine surgeons to be aware of the potential to cause iatrogenic cervical deformity. The aim of this review is to highlight concepts and techniques to prevent cervical deformity after spine surgery.

Morphology of the Cervical Spine Alignment in Scheuermann’s Disease

Article

Feb 2019

Piotr Janusz

Defining Cervical Sagittal Plane Deformity – When Are Sagittal Realignment Procedures Necessary in Patients Presenting Primarily With Radiculopathy or Myelopathy?

Article

Full-text available

Dec 2022

Objective: It remains unclear whether cervical sagittal deformity (CSD) should be defined by radiographic parameters alone versus both clinical and radiographic factors, and whether radiographic malalignment by itself warrants a CSD corrective surgery in patients who present primarily with neurologic symptoms. Methods: We administered a survey to a group of expert surgeons to evaluate whether radiographic parameters alone were sufficient to diagnose CSD, and in which scenarios surgeons recommend a CSD realignment procedure versus addressing the neurologic symptoms alone. Results: No single radiographic criteria reached a 50% threshold as being sufficient to establish the diagnosis of CSD. When asymptomatic radiographic malalignment was present, a sagittal deformity correction was more likely to be recommended in patients with myelopathy versus those with radiculopathy alone. The majority of surgeons recommended deformity correction when symptoms of cervical deformity were present in addition to radiographic malalignment (85% with deformity symptoms and radiculopathy, 93% with deformity symptoms and myelopathy). Conclusion: There is no consensus on which radiographic and/or clinical criteria are necessary to define the presence of CSD. We recommend that symptoms of cervical deformity, in addition to radiographic parameters, be considered when deciding whether to perform deformity correction in patients who present primarily with myelopathy or radiculopathy.

Operative treatment outcomes for adult cervical deformity: a prospective multicenter assessment with mean 3-year follow-up

Article

Jul 2022
J NEUROSURG-SPINE

Objective: Adult cervical deformity (ACD) has high complication rates due to surgical complexity and patient frailty. Very few studies have focused on longer-term outcomes of operative ACD treatment. The objective of this study was to assess minimum 2-year outcomes and complications of ACD surgery. Methods: A multicenter, prospective observational study was performed at 13 centers across the United States to evaluate surgical outcomes for ACD. Demographics, complications, radiographic parameters, and patient-reported outcome measures (PROMs; Neck Disability Index, modified Japanese Orthopaedic Association, EuroQol-5D [EQ-5D], and numeric rating scale [NRS] for neck and back pain) were evaluated, and analyses focused on patients with ≥ 2-year follow-up. Results: Of 169 patients with ACD who were eligible for the study, 102 (60.4%) had a minimum 2-year follow-up (mean 3.4 years, range 2-8.1 years). The mean age at surgery was 62 years (SD 11 years). Surgical approaches included anterior-only (22.8%), posterior-only (39.6%), and combined (37.6%). PROMs significantly improved from baseline to last follow-up, including Neck Disability Index (from 47.3 to 33.0) and modified Japanese Orthopaedic Association score (from 12.0 to 12.8; for patients with baseline score ≤ 14), neck pain NRS (from 6.8 to 3.8), back pain NRS (from 5.5 to 4.8), EQ-5D score (from 0.74 to 0.78), and EQ-5D visual analog scale score (from 59.5 to 66.6) (all p ≤ 0.04). More than half of the patients (n = 58, 56.9%) had at least one complication, with the most common complications including dysphagia, distal junctional kyphosis, instrumentation failure, and cardiopulmonary events. The patients who did not achieve 2-year follow-up (n = 67) were similar to study patients based on baseline demographics, comorbidities, and PROMs. Over the course of follow-up, 23 of the total 169 enrolled patients were reported to have died. Notably, these represent all-cause mortalities during the course of follow-up. Conclusions: This multicenter, prospective analysis demonstrates that operative treatment for ACD provides significant improvement of health-related quality of life at a mean 3.4-year follow-up, despite high complication rates and a high rate of all-cause mortality that is reflective of the overall frailty of this patient population. To the authors' knowledge, this study represents the largest and most comprehensive prospective effort to date designed to assess the intermediate-term outcomes and complications of operative treatment for ACD.

Analysis of Associating Radiologic Parameters With Clinical Outcomes After Posterior C1–2 Fusion

Article

Full-text available

May 2022

Objective: To evaluate which radiologic parameters affect clinical outcomes in patients underwent posterior C1-C2 fusion for atlantoaxial dislocation. Methods: From January 2014 to December 2017, among 98 patients underwent C1-C2 posterior fusion, patients with previous cervical surgery or extending to subaxial spine or basilar invagination were excluded. Finally, 38 patients were included. O-C2, C1-2, C1-C7, C2-C7 cobb angle (CA), T1 slope, C1-C7, C2-C7 sagittal vertical axis (SVA), and posterior atlantodental interval (PADI) were measured at preoperative and postoperative one year. The difference between postoperative and preoperative values for each parameter was designated as Δvalue. Postoperative subaxial kyphosis (PSK) was defined to decrease ≥10° at subaxial spine. VAS, JOA score, NDI were used to evaluate clinical outcomes. Results: Mean age was 54.4±15.9. Male to female was 14 to 24. Of radiologic parameters, C1-C7 SVA and PADI were significantly changed from 26.4±12.9mm, 17.1±3.3mm to 22.6±13.0mm, 21.6±3.4mm. △C1-C2 CA was correlated with △C1-7 CA and △C2-7 SVA. ΔPADI correlates with ΔO-C2 CA. VAS correlates with △C1-C7 CA (P = 0.03). JOA score also correlates with △C2-C7 SVA (P = 0.02). NDI was associated with ΔPADI (P < 0.01). The incidence of PSK was 23.7%, and not significant with clinical outcomes. Conclusion: △C1-C2 CA was correlated with ΔC1-C7 CA, ΔC2-C7 SVA. ΔC1-C7 CA, ΔC2-C7 SVA, and ΔPADI were the key radiologic parameters to influence clinical outcomes. Postoperative C1-C2 angle should be carefully determined as a factor affecting clinical outcomes and cervical sagittal alignment.

Finger trembling improvement after surgery in Hirayama disease: a case report

Article

Apr 2022

Introduction: Finger trembling is a characteristic physical finding in Hirayama disease. Although conservative treatment is recommended to stop disease progression, surgery is optional in some cases. However, the postoperative recovery of finger trembling is scarcely reported. Case presentation: A 26-year-old Japanese female patient whose chief complaint was left finger trembling with active finger extension presented at our hospital. Hand weakness without muscle atrophy of the left arm was observed. MRI showed left-side oriented intramedullary signal change with concomitant cord atrophy at C4-5 and C5-6. The CT myelogram (CTM) on flexion showed anterior cord compression and anterior shift of posterior dura matter from C4 to C6. And CTM on extension showed the resolution of both findings. Electrophysiological studies showed active and chronic neuronal damage and preserved motor neuron pool of hand muscle. Since she had exhibited a gradual aggravation of symptoms over a period of 5 years, she underwent anterior cervical discectomy and fusion after careful assessment of both conservative and surgical treatment. Finger trembling recovered soon after surgery. Discussion: Finger trembling is an unfamiliar physical finding in terms of postoperative recovery prediction. Anterior horn cell impairment is postulated as a cause of finger trembling. Postural restoration of spinal cord shape and cerebrospinal fluid around the cord with preserved neural function could facilitate functional recovery.

Deep Learning Algorithm to Evaluate Cervical Spondylotic Myelopathy Using Lateral Cervical Spine Radiograph

Article

Full-text available

Apr 2022
BMC NEUROL

Background Deep learning (DL) is an advanced machine learning approach used in different areas such as image analysis, bioinformatics, and natural language processing. A convolutional neural network (CNN) is a representative DL model that is highly advantageous for imaging recognition and classification This study aimed to develop a CNN using lateral cervical spine radiograph to detect cervical spondylotic myelopathy (CSM). Methods We retrospectively recruited 207 patients who visited the spine center of a university hospital. Of them, 96 had CSM (CSM patients) while 111 did not have CSM (non-CSM patients). CNN algorithm was used to detect cervical spondylotic myelopathy. Of the included patients, 70% (145 images) were assigned randomly to the training set, while the remaining 30% (62 images) to the test set to measure the model performance. Results The accuracy of detecting CSM was 87.1%, and the area under the curve was 0.864 (95% CI, 0.780-0.949). Conclusion The CNN model using the lateral cervical spine radiographs of each patient could be helpful in the diagnosis of CSM.

Internal Chain of Correlation of Sagittal Cervical Alignment in Asymptomatic Subjects

Article

Full-text available

Mar 2022

Study Design Cross-sectional observational study in a prospective cohort. Objective To analyze the cervical alignment characteristics and their chain of correlation in a sample of asymptomatic individuals. Methods Asymptomatic adults who had full spinal radiographs performed. Cervical radiographic parameters were measured, including upper cervical curvature (McGregor line-C2), lower cervical curvature (C2-C7), McGregor slope, and sagittal vertical axis from C2-C7 (CSVA) and T1-slope (T1S). Subjects were stratified by age into 3 groups (18-39 years, 40-59 years, and >60 years), and radiographic parameters were compared across age groups and based on sex. Results 102 asymptomatic subjects (mean age, 50 years) were included. The T1S significantly increased with age, accompanied by an increase in C2-C7 lordosis. The cervical sagittal alignment, represented by CSVA, did not significantly differ based on age. There was a close correlation among the cervical sagittal parameters, such that the CSVA may be predicted based on the T1S and C2-C7 lordosis. Comparisons of the normative values identified in the present study with those reported in previous studies demonstrate variability in what constitutes normal in different populations. Conclusion This analysis of cervical alignment in a sample of asymptomatic volunteers revealed that with increasing age there is an observed increase in the sagittal inclination of the base of the cervical spine (T1S) that is accompanied by an increase in cervical lordosis as a means of maintaining cervical sagittal alignment (CSVA). The variability in what constitutes normal values for cervical parameters suggests that further study is warranted using standardized methodologies across diverse populations.

Association between pre-operative sagittal alignment and radiographic measures of decompression following cervical laminectomy: a retrospective cohort study

Article

Full-text available

Sep 2021

Background: The primary purpose of this study was to determine the association between pre-operative cervical sagittal alignment and the extent of cord decompression in the form of increased spinal cord width and cerebrospinal fluid (CSF) space in front of and behind the cord in patients undergoing laminectomy for cervical spondylotic myelopathy (CSM). Secondary objectives included an assessment of the correlation between increasing numbers of levels decompressed and the post-operative cervical spine sagittal alignment, the effect of laminectomy on the change in alignment, as well as effect of laminectomy on pre-existing spinal cord signal abnormality. Methods: This retrospective cohort study included patients who underwent cervical laminectomies, without fusion, between 2015 and 2020. Chart review was used to collect baseline variables. Cervical sagittal alignment, width of the spinal cord, and the CSF space in-front and behind the cord was measured pre-operatively and post-operatively using magnetic resonance imaging (MRI) scans for each patient. The correlation between change in measured parameters and pre-operative cervical sagittal alignment was assessed using Spearman's correlation. Results: Thirty-five patients were included. Average age was 65.29±10.98 years old. The majority of patients (80%) underwent laminectomies at 3-4 levels. Average pre-operative sagittal alignment determined by the Cobb angle was 6.05°±14.17°, while the average post-operative Cobb angle was 3.15°±16.64°. The change in Cobb angle was not statistically significant (P=0.998). Eleven patients (32%) had pre-operative kyphotic sagittal alignment. The average time from surgery to post-operative MRI scan was 20.44±13.18 months (range, 3-39; median, 18.5; IQR, 23.5). There was no statistically significant association between increasing levels of decompression and change in alignment (P=0.546). Cord signal abnormality persisted after decompression. There was a moderate correlation between lordotic pre-operative cervical sagittal alignment and change in space in-front of the cord (correlation coefficient 0.337, P=0.048) and change in cord width (correlation coefficient 0.388, P=0.021). Conclusions: Severity of pre-operative kyphotic sagittal alignment is associated with decreased spinal cord drift and extent of decompression. The pre-operative sagittal alignment is not significantly associated with the change in post-operative alignment. Increasing number of levels decompressed does not worsen a kyphotic cervical spine sagittal alignment.

Factors associated with postoperative axial symptom after expansive open-door laminoplasty: retrospective study using multivariable analysis

Article

Full-text available

Nov 2020
EUR SPINE J

PurposeThe aim of the present study was to investigate the factors associated with axial symptom using multivariable analysis.Methods The authors retrospectively assessed 249 patients treated by open-door laminoplasty. The patients were classified into two groups: axial symptom and no axial symptom group. The possible factors included demographic variables (age, sex, BMI, smoking, heart disease, diabetes, preoperative neck pain, preoperative JOA scores, preoperative NDI, course of disease and pathogenesis) and surgical and radiological variables [operation time, intraoperative blood loss, collar wear time, preoperative cervical curvature, postoperative cervical curvature, T1 slope, preoperative and postoperative C2 sagittal vertical axis (C2 SVA)].ResultsThe prevalence of axial symptom was 34.9% (89/249). The collar wear time, preoperative and postoperative C2 SVA were risk factors for axial symptom. A cutoff value of 22.6 mm for preoperative C2 SVA and 3.5 weeks for collar wear time predicted the development of axial symptom.Conclusions The longer collar wear time, larger preoperative and postoperative C2 SVA were positively correlated with the higher incidence of axial symptom.

Trends in Posterior Cervical Fusion for Deformity in the United States from 2000 to 2017

Article

Full-text available

Jun 2020

BACKGROUND Posterior cervical decompression and fusion (PCF) is a common treatment for cervical spondylotic myelopathy. Treatment paradigms are shifting from simple decompression and fusion to correcting cervical deformities. OBJECTIVE To identify trends in PCF with an emphasis on cervical deformity and surgical complexity. METHODS Adults who underwent PCF from 2000 to 2017 were retrospectively identified in the Premier Healthcare Database (PHD) using International Classification of Disease Codes (ICD) 9 and 10. Patients were dichotomized into those with or without deformity diagnosis. PCF complexity was defined by adjunct surgical codes, including anterior cervical fusion, extension to thoracic levels, and osteotomy. Patient characteristics, including demographics, functional comorbidity index (FCI), and hospital characteristics, were extracted and annual procedures were projected to the US population. RESULTS A total of 68 415 discharges for PCF were identified. Compound annual growth rate (CAGR) of PCF from 2000 to 2017 for nondeformity cases was 9.7% and 16.5% for deformity. The demographics with the greatest growth were deformity patients aged 65 to 74 yr (15.1%). The CAGR of anterior cervical fusion and extension to thoracic levels was higher for deformity patients compared to nondeformity patients, 13.6% versus 3.9% and 20.4% versus 16.6%, respectively. CONCLUSION Rates of PCF for deformity are increasing at a greater rate than nondeformity PCF. The most growth was seen among deformity patients aged 65 to 74 yr. Surgical complexity is also changing with increasing use of anterior cervical fusion and extension of PCF to include thoracic levels.

The Effect of Head Loading on Cervical Spine in Manual Laborers

Article

Full-text available

Mar 2020

Study design: A prospective case-control study. Purpose: To determine the effect of axial loading on the cervical spine when weights are carried on the head. Overview of literature: Traditionally, carrying weights on the head has been a common practice in developing countries. The laborers working in agriculture, construction, and other industries, as well as porters at railway platforms, are required to lift heavy weights. Since controversy exists regarding carrying weights on the head, we decided to evaluate its effect on the cervical spine. Methods: The study comprised 62 subjects. Of this number, 32 subjects (group A) were unskilled laborers from the construction industry; the other 30 subjects (group B) were in the control group and had never previously carried heavy weights on their heads. Cervical spine radiographs were taken for all the 62 subjects. Subjects in group A were asked to carry a load (approximately 35 kg) on their heads and walk for about 65 m, with their cervical spine radiographs taken afterward. Results: The mean ages of patients in groups A and B were 27.17 and 25.75 years, respectively. The mean cervical lordosis observed in group A (18.96°) was dramatically less compared with group B (25.40°), showing a further decrease in head loading (3.35°). Five subjects had a reversal of lordosis (-5.61°). A statistically significant reduction in disc height and listhesis was observed when the load was carried on the head with a further decrease after walking with the load. Accelerated degenerative changes, particularly affecting the upper cervical spine, were observed in head loaders. Conclusions: Carrying a load on the head leads to accelerated degenerative changes, which involve the upper cervical spine more than the lower cervical spine and predisposes it to injury at a lower threshold. Thus, alternative methods of carrying loads should be proposed.

Imaging in myelopathy, Symposium – Cervical Spondylo-myelopathy. Indian Spine journal, Year : 2019 | Volume : 2 | Issue : 1 | Page : 20-32. DOI: 10.4103/isj.isj_63_18.

Article

Feb 2020

Sri Vijay Anand K S

The Sagittal Balance of the Cervical Spine: Radiographic Analysis of Interdependence between the Occipitocervical and Spinopelvic Alignment

Article

Full-text available

Jan 2020

Study design: This was a prospective clinical study. Purpose: Previous studies have indicated that cervical lordosis is a parameter influenced by segmental and global spinal sagittal balance parameters. However, this correlation still remains unclear. Therefore, a better understanding of the normal values and interdependencies between inter-segmental alignment parameters is needed. This is a preliminary analysis that helps to understand these factors. Overview of literature: Change in global sagittal alignment is associated with poor health-related quality of life. Questions regarding which parameters play the primary roles in the progression of spinal sagittal imbalance and which might be compensatory factors remain unanswered. Methods: Prospectively, 420 adults (105 asymptomatic, 105 cervical symptomatic, 105 lumbar symptomatic, and 105 post-surgical) were selected. Whole-spine standing lateral radiographs were taken, and spinopelvic, thoracic, and cervical parameters were measured. Then, the data were analyzed using correlation coefficient test and multiple regression analysis. Results: All the parameters showed a normal distribution. The mean values of the cervical parameters are as follows: C1C2 Cobb angle, -27.07°±4.3°; C2C7 Cobb angle, -16.4°±5.6°; OCC2 Cobb angle, -14.5°±3.8°; OCC7 Cobb angle, -29.8°±5.6°; C2C7 Harrison angle, 20.4°±4.3°; and C7 slope, -25.4°±5.6°. The analysis of these parameters revealed no statistically significant difference between asymptomatic, symptomatic, and post-surgical patients. C7 sagittal vertical axis (SVA) correlated with the C2C7 Cobb angle (r =0.7) in all groups. No significant correlation was noted between cervical and spinopelvic parameters in asymptomatic patients. However, C1C2 Cobb angle correlated significantly with pelvic incidence (PI, r =-0.2), lumbar lordosis (LL, r =0.2), and pelvic tilt (PT, r =-0.2) in cervical symptomatic patients. Irrespective of the patient symptom sub-group (n=420), C1C2 Cobb angle correlated with LL (r =0.1) and C2C7 Harrison angle correlated with PI and PT (r =0.1). Conclusions: Our results indicate significant interdependence between the spinopelvic and cervical alignment, especially in cervical symptomatic patients. In addition, strong correlation was found between the C7 SVA and C2C7 Cobb angle. Overall, the results of this study could help to better understand the cervical sagittal alignment and serve as preliminary data for planning surgical reconstruction procedures.

Creation of a Porcine Kyphotic Model

Article

Mar 2019

Study design: Large animal study. Objective: Create a thoracic hyperkyphotic deformity in an immature porcine spine, so that future researchers may use this model to validate spinal instrumentation and other therapies used in the treatment of hyperkyphosis. Summary of background data: Although several scoliotic animal models have been developed, there have been no reports of a thoracic hyperkyphotic animal model creation in an immature animal. The present study was designed to produce a porcine hyperkyphotic model by the time the pig weighed 25 kg, which corresponds to the approximate weight of a child undergoing surgery for early-onset scoliosis (EOS). Methods: Successful surgical procedures were performed in 6 consecutive 10-kg (male, 5-week-old) immature Yorkshire pigs. Procedure protocol consisted of 1) a left thoracotomy at T10-T11, 2) screw placement at T9 and T11, 3) partial vertebrectomy at T10, 4) posterior interspinous ligament transection, and 5) placement of wire loop around screws and tightening. Weekly x-ray imaging was performed preoperatively and postoperatively, documenting progressively increasing kyphosis as the pig grew. Necropsy was performed 5-6 weeks after surgery, with CT, slab section, and histologic analysis. Results: Average T9-T11 kyphosis (measured by sagittal Cobb angle) was 6.1° ± 1.4° (mean ± SD) preoperatively, 30.5° ± 1.0° immediately postoperation, and significantly increased to 50.3° ± 7.2° (p < .0001) over 5-6 weeks in 6 consecutive pigs at time of necropsy. Conclusions: An animal model of relatively more rigid-appearing thoracic hyperkyphotic deformities in immature pigs has been created. Subsequent studies addressing management of early-onset kyphosis with spinal instrumentation are now possible. Level of evidence: Level V.

Cervical Deformity and Treatment Algorithms

Chapter

Jan 2015

Cervical kyphoscoliosis due to substance abuse: a case series on introduction and neurosurgical treatment

Article

Oct 2024

A prospective case series. To investigate the possible associations of multi-directional cervical kyphoscoliosis (CKS) with substance abuse and evaluate treatment outcomes. CKS is a rare medical situation without a well-established pathology. Still there are many obscurities in treatment paradigms and outcomes. To our knowledge, there is no published report on the association between CKS with addiction. Besides the novel report of such a rare etiology for CSK, the complexity of the neurosurgical treatment makes this report the first of its kind. In this series, we presented three patients with a history of crack cocaine addiction who suffered CKS due to prolonged hand-over-neck posture and treated all of them with a complex neurosurgical protocol. All cases were operated on and restored their normal spine alignment. Their long-term outcomes showed independent neurological status with no major surgical complications. Crack cocaine addiction might be associated with CKS in long-term cocaine abuse. A complex neurosurgical approach can achieve a sustainable clinical outcome.

Comparison of the Effects of Posterior Cervical Fixation or Posterior Cervical Fixation Extending to the Upper Thoracic Region on Cervical Sagittal Alignment

Article

Full-text available

Jul 2024

Objective For degenerative diseases accompanied by cervical malalignment, the starting and ending points of fixation for better cervical sagittal alignment and clinical results are not as clear as the thoracolumbar region. In this study we aimed to compare the effects of posterior subaxial cervical fixation (PSCF), posterior cervical fixation extending to the upper thoracic region and posterior upper cervical fixation extending to the upper thoracic region on cervical sagittal alignment. Methods Sixty‐three patients who underwent posterior cervical and cervical‐up thoracic fixation were retrospectively analyzed in a comparative study. The procedures that we performed from May 2019 to March 2022 on these 63 patients were: (1) C3‐C6 group—posterior subaxial cervical fixation; (2) Subaxial‐T2 group—posterior subaxial cervicothoracic fixation (PSCTF); (3) C2‐T2 upper thoracic posterior fixation group. The C3‐C6 group had 27 patients, Subaxial‐T2 group had 24, and C2‐T2 group had 12. We determined the minimum follow‐up period as 12 months. C0‐2, C2‐7 lordosis angle, sagittal vertical axis (SVA), C2 slope, C7 slope, T1 slope, cervical slope, neck slope, and thoracic inlet angle (TIA) measurements were made in three patient groups. Comparatively, cervical sagittal alignment was evaluated. Result In the C2‐T2 group, a significant increase in C2‐C7 lordosis, decrease in C2 slope, and increase in TS‐CL were observed. Significant C2‐C7 lordosis decrease, C2 slope increase, and TS‐CL decrease were observed in the C3‐C6 group. A significant increase in C2‐C7 lordosis and a decrease in C2 slope were observed in the subaxial‐T2 group. No significant change was observed in the TS‐CL angle. Conclusion In cervical degenerative disorders accompanied by cervical malalignment, we recommend the C2‐T2 fixation method, which provides the desired C2‐C7 lordosis, SVA within the normal range, and the best Neck Disability Index results.

The preservation of cervical flexibility helps maintain cervical sagittal alignment after laminoplasty

Article

Jun 2024
SPINE J

Principles of the anterior controllable antedisplacement and fusion technique

Chapter

Jan 2024

Jiangang Shi

Adult cervical spine deformity: a state-of-the-art review

Article

Sep 2023

Adult cervical deformity is a structural malalignment of the cervical spine that may present with variety of significant symptomatology for patients. There are clear and substantial negative impacts of cervical spine deformity, including the increased burden of pain, limited mobility and functionality, and interference with patients’ ability to work and perform everyday tasks. Primary cervical deformities develop as the result of a multitude of different etiologies, changing the normal mechanics and structure of the cervical region. In particular, degeneration of the cervical spine, inflammatory arthritides and neuromuscular changes are significant players in the development of disease. Additionally, cervical deformities, sometimes iatrogenically, may present secondary to malalignment or correction of the thoracic, lumbar or sacropelvic spine. Previously, classification systems were developed to help quantify disease burden and influence management of thoracic and lumbar spine deformities. Following up on these works and based on the relationship between the cervical and distal spine, Ames-ISSG developed a framework for a standardized tool for characterizing and quantifying cervical spine deformities. When surgical intervention is required to correct a cervical deformity, there are advantages and disadvantages to both anterior and posterior approaches. A stepwise approach may minimize the drawbacks of either an anterior or posterior approach alone, and patients should have a surgical plan tailored specifically to their cervical deformity based upon symptomatic and radiographic indications. This state-of-the-art review is based upon a comprehensive overview of literature seeking to highlight the normal cervical spine, etiologies of cervical deformity, current classification systems, and key surgical techniques.

Changes in T1 slope and cervical sagittal vertical axis correlate to improved neurological function recovery after cervical laminoplasty

Article

Full-text available

Sep 2022

Purpose: To investigate the influence of changes in T1 slope (T1S) and cervical sagittal vertical axis (CSVA) on cervical laminoplasty outcomes. Methods: Eighty-one patients with cervical spondylotic myelopathy (CSM) treated with cervical laminoplasty were enrolled in this study. Demographic parameters included age and follow-up time. Imaging data included occiput-C2 lordosis (OC2), C2-C7 Cobb angle (CL), T1S, CSVA. Outcome assessment indicators included the Japanese Orthopedic Association (JOA) score, JOA recovery rate, and neck disability index (NDI). All patients were grouped based on preoperative T1S and variation in CL after surgery, respectively. Patients with decreased CL postoperatively were further grouped according to whether they were combined with T1S reduction. Results: There were no significant differences in the final JOA score, JOA recovery rate, or NDI between patients with different T1S. Patients with loss of CL postoperatively had lower JOA score and JOA recovery rate, but higher NDI than patients with sustained CL. Furthermore, patients with CL loss but compensate for it with reduction in T1S had lower CSVA, higher JOA score and JOA recovery rate than those with CL loss alone. Conclusions: Decreased T1S postoperatively prevents the tendency of the cervical spine to tilt forward by regulating CSVA and facilitates recovery of neurological function after cervical laminoplasty.

Clinical significance of the C2 slope after multilevel cervical spine fusion

Article

Aug 2022

OBJECTIVE The C2 slope (C2S) is one of the parameters that can determine cervical sagittal alignment, but its clinical significance is relatively unexplored. This study aimed to evaluate the clinical significance of the C2S after multilevel cervical spine fusion. METHODS A total of 111 patients who underwent multilevel cervical spine fusion were included in this study. The C2S, cervical sagittal vertical axis (cSVA), C2–7 lordosis, and T1 slope (T1S) were measured in standing lateral cervical spine radiographs preoperatively and 2 years after the surgery. Clinical outcome measures were visual analog scale (VAS) neck and arm pain scores, Neck Disability Index (NDI), Japanese Orthopaedic Association (JOA) scale score, and patient-reported subjective improvement rate (IR) percentage. Statistical analysis was performed using a paired-samples t-test and Pearson’s correlation, and a receiver operating characteristic (ROC) curve to determine the cutoff values of C2S. RESULTS C2S demonstrated a significant correlation with the cSVA, C2–7 lordosis, T1S, and T1S minus cervical lordosis. C2S revealed a significant correlation with the JOA, neck pain VAS, and NDI scores at 2 years after surgery. Change in the C2S correlated with postoperative neck pain and NDI scores. ROC curves demonstrated the cutoff values of C2S as 18.8°, 22.25°, and 25.35°, according to a cSVA of 40 mm, severe disability expressed by NDI, and severe myelopathy, respectively. CONCLUSIONS C2S can be an additional cervical sagittal alignment parameter that can be a useful prognostic factor after multilevel cervical spine fusion.

Investigation of Titanium Mesh and Nano-Hydroxyapatite/Polyamide 66 Bone Graft in Cervical Reconstruction of Spondylosis After Sub-Total Vertebral Body Resection

Article

Apr 2022
J BIOMED NANOTECHNOL

The nano-hydroxyapatite/polyamide 66 (n-HA/PA66) bionic bone column, as a high-performance tissue repair and replacement material, introduced as a high osteo-induction ability agent. Nanomaterial has significantly taken a place in orthopedic surgery, however, the efficacy of using n-HA/PA66 is yet to be established. In this regard, this study evaluated various sagittal parameters (such as imaging measurement) and clinical efficacy in postoperative patients, whom underwent cervical reconstruction surgery due to cervical spondylosis myelopathy (CSM). In this study, total 62 CSM cases were enrolled between October 2016 to March 2020, and were hospitalized for cervical reconstruction surgery. 31 cases were grafted with titanium mesh and 31 cases were grafted with n-HA/P66. The sagittal parameters such as cervical spine lateral radiographs (C 0–2 Coob, C 2–7 Coob, T1S, CSVA, and TIA) were taken before operation, after operation (within 1 week), 3, 6, and 9 months after operation. In order to evaluate the clinical efficacy, we used JOA scores before, after, 3 months, 6 months and 9 months after operation. Results showed that JOA scores after the re-examination in the two groups (titanium and n-HA/P66) were significantly higher than before the operation, suggesting a well postoperative functional recovery after surgery in both groups; however, there was no significant difference in JOA score and JOA improvement index between the two groups. In regard of angles measurement (C 0–2 Cobb, C 2–7 Cobb, T1S, CSVA, and TIA), we observed no significant difference between these two groups before and after the operation. In addition, we showed that C 0–2 Cobb and C 2–7 Cobb angle had a significant positive correlation; and C 0–2 Cobb angle is positively correlated with T1S, and negatively correlated with CSVA. Both titanium mesh and n-HA/PA66 can be well improved and maintained within 9 months after surgery with clinical efficacy, however, using n-HA/PA66 might have more benefits.

Commentary: Case Report of Angular Post-Tuberculotic Kyphosis Corrected Through Pedicle Subtraction Osteotomy Above C7

Article

Dec 2021

Postoperative Cervicothoracic Kyphosis Following Infantile Intramedullary Tumor Resection Accelerates Neurological Deterioration

Article

Full-text available

Oct 2021

Intramedullary spinal cord tumors are rare in children. Regardless of the type of tumor, surgical removal is thought to improve progression-free survival. However, postoperative kyphosis is a serious problem in children, who can expect long-term survival. We present a pediatric case of neurofibromatosis type 2-related spinal ependymoma at the cervicothoracic regions where acute neurological deterioration was developed due to a combination of tumor recurrence and postoperative kyphotic deformity. In the first surgery, subtotal tumor resection was performed via osteoplastic laminotomy. Postoperative radiological evaluation at several months showed cervicothoracic junctional kyphosis, which subsequently made a significant improvement by lifestyle instructions. However, 22 months after the surgery, he exhibited rapid neurological deterioration caused by the regrowth of the recurrent tumor and re-emergence of kyphotic deformity, which led to the fixed laminar flap sank into the spinal canal. Therefore, a second surgery was performed 23 months after the first surgery, and gross total removal was achieved. Osteoplastic laminotomy is presumed to reduce the occurrence of postoperative kyphosis compared with laminectomy, but there have been no reports on the spinal cord compression by plunging of the re-fixed laminar flap into the spinal canal. The kyphosis deformity increases the chance of re-fixed laminar flap coming off, thereby accelerating neurological injury on top of the neural damage by tumor recurrence itself. Therefore, pediatric patients with spinal cord tumors should be carefully managed in terms of recurrent tumors and postoperative kyphosis, and timely surgical intervention is necessary before kyphotic deformity becomes evident.

Radiological factors associated with the severity of corticospinal tract dysfunctions for cervical spondylotic myelopathy: An analysis of the central motor conduction time and kinematic CT myelography

Article

Dec 2021
J CLIN NEUROSCI

Patients with cervical spondylotic myelopathy (CSM) often exhibit symptoms in clinical practice, particularly the elderly, whose lower extremity functions are more likely to deteriorate; however, the underlying mechanisms currently remain unclear. The present study aimed to elucidate the relationship between the neurological severity of CSM based on an electrophysiological examination and radiological findings. Eighty-six patients with CSM were examined using kinematic CT myelography. The cross-sectional area of the spinal cord and dynamic changes in the spinal cord were measured at the affected level. The central motor conduction time (CMCT) using transcranial magnetic stimulation was calculated as follows: motor evoked potential latency - (compound muscle action potential latency + F latency − 1)/2 (ms). A multiple logistic regression analysis was performed to identify the radiological parameters associated with severe lower limb dysfunction. CMCT in the upper limbs correlated with spinal cord compression during neck extension, while that in the lower limbs correlated with a larger C2-7 sagittal vertical axis, cervical lordosis, a small C2-7 range of motion (ROM), and spinal cord compression during neck flexion. In a multiple logistic regression analysis, significant risk factors specific for severe lower limb dysfunction were greater anterior spondylolisthesis during neck extension (P = 0.006, OR: 2.53, 95%CI: 1.13–2.07) and small C2-7 ROM in neutral to flexion (P = 0.035, OR: 0.67, 95%CI: 0.52–0.88). Imaging findings affect upper and lower extremity functions in specific manners. Cervical stiffness or anterior compression factors may be associated with the deterioration of lower limb function.

The Frontier of Treatment for Cervical Degenerative Disorders頚椎変性疾患に対する治療のフロンティア

Article

Jan 2021

Toshitaka Seki

Currently, the gold standard for the surgical treatment of cervical degenerative diseases is anterior cervical discectomy and fusion (ACDF) and laminoplasty (or laminectomy). However, unresolved problems include adjacent segment disease after ACDF and kyphosis after laminoplasty (or laminectomy). As a recent topic for cervical degenerative diseases, the new anterior technique, which is anterior cervical disc replacement (ACDR), has become available in Japan. ACDR is a relatively new motion-preserving procedure and is expected to prevent adjacent segment disease. Although good surgical results have been reported in Western and Asian countries except for Japan, where it has been introduced in advance. The long-term results in Japan are unknown, and careful follow-up is required. Cervical laminoplasty (or laminectomy) is indicated for cases with the preoperative alignment of lordosis or mild kyphosis. Despite the maintenance of preoperative alignment, some patients have poor postoperative surgery results. Therefore, the concept of cervical spine sagittal balance was proposed, as well as the thoracolumbar spine sagittal balance. The C2-C7 sagittal vertical axis, which indicates the anterior deviation of the cervical spine ; the chin-brow to vertical angle, which is an index of horizontal vision ; the T1 Slope, which is an index of cervical lordosis ; and cervical lordosis are used as the parameters of cervical spine sagittal balance. It is becoming an index for selecting surgical procedures.

The associations between radiological and neurological findings of degenerative cervical myelopathy: radiological analysis based on kinematic CT myelography and evoked potentials of the spinal cord

Article

Jul 2021

OBJECTIVE Neurological and imaging findings play significant roles in the diagnosis of degenerative cervical myelopathy (DCM). Consistency between neurological and imaging findings is important for diagnosing DCM. The reasons why neurological findings exhibit varying sensitivity for DCM and their associations with radiological findings are unclear. This study aimed to identify associations between radiological parameters and neurological findings in DCM and elucidate the utility of concordance between imaging and neurological findings for diagnosing DCM. METHODS One hundred twenty-one patients with DCM were enrolled. The Japanese Orthopaedic Association (JOA) score, radiological parameters, MRI and kinematic CT myelography (CTM) parameters, and the affected spinal level (according to multimodal spinal cord evoked potential examinations) were assessed. Kinematic CTM was conducted with neutral positioning or at maximal extension or flexion of the cervical spine. The cross-sectional area (CSA) of the spinal cord, dynamic change in the CSA, C2–7 range of motion, and C2–7 angle were measured. The associations between radiological parameters and hyperreflexia, the Hoffmann reflex, the Babinski sign, and positional sense were analyzed via multiple logistic regression analysis. RESULTS In univariate analyses, the upper- and lower-limb JOA scores were found to be significantly associated with a positive Hoffmann reflex and a positive Babinski sign, respectively. In the multivariate analysis, a positive Hoffmann reflex was associated with a higher MRI grade (p = 0.026, OR 2.23) and a responsible level other than C6–7 (p = 0.0017, OR 0.061). A small CSA during flexion was found to be significantly associated with a positive Babinski sign (p = 0.021, OR 0.90). The presence of ossification of the posterior longitudinal ligament (p = 0.0045, OR 0.31) and a larger C2–7 angle during flexion (p = 0.01, OR 0.89) were significantly associated with abnormal great toe proprioception (GTP). CONCLUSIONS This study found that the Hoffmann reflex is associated with chronic and severe spinal cord compression but not the dynamic factors. The Babinski sign is associated with severe spinal cord compression during neck flexion. The GTP is associated with large cervical lordosis. These imaging features can help us understand the characteristics of the neurological findings.

Redefining cervical spine deformity classification through novel cutoffs: An assessment of the relationship between radiographic parameters and functional neurological outcomes

Article

Full-text available

Apr 2021
J Craniovertebr Junction Spine

Purpose: The aim is to investigate the relationship between cervical parameters and the modified Japanese Orthopedic Association scale (mJOA). Materials and methods: Surgical adult cervical deformity (CD) patients were included in this retrospective analysis. After determining data followed a parametric distribution through the Shapiro-Wilk Normality (P = 0.15, P > 0.05), Pearson correlations were run for radiographic parameters and mJOA. For significant correlations, logistic regressions were performed to determine a threshold of radiographic measures for which the correlation with mJOA scores was most significant. mJOA score of 14 and <12 reported cut-off values for moderate (M) and severe (S) disability. New modifiers were compared to an existing classification using Spearman's rho and logistic regression analyses to predict outcomes up to 2 years. Results: A total of 123 CD patients were included (60.5 years, 65%F, 29.1 kg/m2). For significant baseline factors from Pearson correlations, the following thresholds were predicted: MGS (M:-12 to-9° and 0°-19°, P = 0.020; S: >19° and <-12°, χ2= 4.291, P = 0.036), TS-CL (M: 26°to 45°, P = 0.201; S: >45°, χ2= 7.8, P = 0.005), CL (M:-21° to 3°, χ2= 8.947, P = 0.004; S: <-21°, χ2= 9.3, P = 0.009), C2-T3 (M: -35° to -25°, χ2= 5.485, P = 0.046; S: <-35°, χ2= 4.1, P = 0.041), C2 Slope (M: 33° to 49°, P = 0.122; S: >49°, χ2= 5.7, P = 0.008), and Frailty (Mild: 0.18-0.27, P = 0.129; Severe: >0.27, P = 0.002). Compared to existing Ames- International Spine Study Group classification, the novel thresholds demonstrated significant predictive value for reoperation and mortality up to 2 years. Conclusions: Collectively, these radiographic values can be utilized in refining existing classifications and developing collective understanding of severity and surgical targets in corrective surgery for adult CD.

Predictive Effect of Cervical Spinal Cord Compression and Corresponding Segmental Paravertebral Muscle Degeneration on the Severity of Symptoms in Patients with Cervical Spondylotic Myelopathy

Article

Mar 2021
SPINE J

Background Context Previous studies have found that cervical sagittal parameters and spinal cord compression are important risk factors for cervical spondylotic myelopathy (CSM). An increasing number of scholars believe that cervical muscle condition is also one of the factors affecting the severity of symptoms in affected patients. Purpose To determine whether: the degree of corresponding segmental paravertebral muscle degeneration is related to the severity of symptoms in patients with CSM; the degree of cervical spinal cord compression can predict the severity of symptoms in patients with CSM. Study Design A retrospective study. Patient Sample From January 2015 to January 2019, 121 patients with CSM were enrolled. Outcome Measures The VAS, NDI and mJOA were used to assess cervical spinal function and quality of life. Methods From January 2015 to January 2019, 121 patients with CSM were enrolled. The inclusion criterion was the presence of complete cervical lateral radiography and MRI data. The following radiographic parameters were measured: (1) C0-C2 Cobb angle; (2) C2-C7 Cobb angle (CL); (3) T1 slope (T1S); (4) neck tilt (NT); (5) C2-C7 sagittal vertical axis (SVA); and (6) T1S-CL. The following MRI parameters were measured: (1) up(low)-fat/muscle; (2) up(low)-fat/centrum; (3) up(low)-muscle/centrum; (4) cervical cord compression index (CCI); (5) S-index; and (6) cervical spinal cord compression area ratio (S0/S1). The VAS, NDI and mJOA were used to assess cervical spinal function and quality of life. The patients were divided into 2 groups according to the mJOA score: group A (mild-moderate symptom group, mJOA score≥12 points) and group B (severe symptom group, mJOA score<12 points). The Pearson correlation coefficient was used to assess the correlations between cervical sagittal parameters, MRI parameters and functional scores. Logistic regression analysis and ROC curve analysis were performed to identify independent risk factors and critical values. Results In patients with CSM, the VAS score is positively correlated with NT, up-fat/centrum, S-index and S0/S1. The NDI is positively correlated with NT, up-fat/muscle, up-fat/centrum, S-index, and S0/S1 and negatively correlated with C0-2N and CL. The mJOA score is positively correlated with CL and negatively correlated with C2-7 SVA, CCI, S-index, and S0/S1. Thus, corresponding segmental paravertebral muscle degeneration has relevance to neck pain, but it is not related to limb weakness, neurological dysfunction, gait impairment, sensation or bladder/bowel function dysfunction. Through mJOA score grouping and binary logistic regression analysis, we found that S0/S1 is the only independent risk factor for severe symptoms in patients with CSM. When S0/S1>0.295, the clinical symptoms of patients are more severe. Thus, in clinical practice, when the degree of spinal cord compression exceeds 30%, the clinical symptoms are more severe. Conclusion In patients with CSM, corresponding segmental paravertebral muscle degeneration has relevance to neck pain, but it does not relate to limb weakness, neurological dysfunction, gait impairment, sensation or bladder/bowel function dysfunction. Cervical spinal cord compression is the only independent risk factor;when the degree of spinal cord compression exceeds 30%, the clinical symptoms are more severe.

Kyphotic Neck and Correlation With Clinical Outcomes

Article

Full-text available

Jan 2016

The association between cervical focal kyphosis and myelopathy severity in patients with cervical spondylotic myelopathy before surgery

Article

Full-text available

Jun 2021
EUR SPINE J

Purpose Cervical focal kyphosis could often be observed in patients with cervical spondylotic myelopathy (CSM). However, the association between it and myelopathy severity remains unclear. This study aims to elucidate the association between cervical focal kyphosis and myelopathy severity before surgery. Methods A retrospective review of 191 consecutive patients treated for CSM from 2017 to 2019 was surveyed. Seven MRI and five radiographic parameters were measured, clinical parameters were included. Patients were divided into two sagittal focal angle groups (lordosis/kyphosis) and two disc herniation severity groups (severe/non-severe). The potential risk factors of myelopathy symptoms were analysed. Results Significant correlations between cervical sagittal focal angles, several other imaging findings and myelopathy severity were found in both total patients (R² = 0.51, P < 0.001) and non-severe disc herniation patients (R² = 0.73, P < 0.001) in multivariate regression models. Compression ratio of spinal cord exhibited the strongest correlation with JOA scores (r = − 0.567, P < 0.001). Cervical focal angles on MRI exhibited a stronger negative correlation with JOA scores (r = − 0.429, P < 0.001) than did angles on the other three postures on radiographs. Dramatic differences in JOA scores could be found in patients with non-severe cervical disc herniation, when a subgroup analysis was performed between cervical lordosis group and more than 4° kyphosis group (14.2 ± 1.7 vs. 11.1 ± 1.7, P < 0.001). Conclusion Cervical focal kyphosis associates with severe myelopathy symptoms in patients with CSM, especially without severe disc herniation. This association may indicate an optimal cervical focal angle in surgical plan. It appeared feasible to assess both the cervical focal angles and spinal cord compression on supine MRI.

Exclusion of Ossified Ligaments Behind C2 Vertebra Combined with Anterior Controllable Antedisplacement and Fusion for Cervical Ossification of the Posterior Longitudinal Ligament Extending to C2 Segment

Article

Dec 2020

Objective To introduce an anterior surgical technique for cervical ossification of posterior longitudinal ligament (OPLL) extending to C2. Methods A total of 29 patients with multilevel OPLL extending to C2 underwent surgery from January 2016 to January 2019. The rationale of our surgical technique is to transect the ossified ligament at the level of C2/3, dividing OPLL into two parts. OPLL behind C2 vertebra is reserved as “focus exclusion”, and OPLL below C2 is performed anterior controllable antedisplacement and fusion (ACAF). Neurological condition was evaluated using the Japanese Orthopeadic Association (JOA) scoring system and its improvement ratio. Radiological assessment included type and extent of OPLL, occupying rate, thickness and length of ossified mass, and curvature of spinal cord. Surgery- and implant-related complications were recorded. Results The mean JOA score increased from 9.4 to 15.8 points at last follow-up, with a significant improvement (P<0.01). The mean preoperative length of the ossified mass behind C2 was 15.4 mm, and its thickness was 2.2 mm, with no significant progression at last follow-up (15.3 mm and 2.2 mm, P>0.05). There was also no statistical difference in OPLL thickness at the largest OR level between preoperation and last follow-up (7.4mm vs. 7.3mm, P>0.05). Four patients presented with cerebrospinal fluid leakage, one with screw displacement and one with dysphagia. Conclusions For patients with cervical OPLL extending to C2, exclusion of ossified ligaments behind C2 combined with ACAF below C2 is an effective and alternative technique.

Impact of Anterior Spondylolisthesis and Kyphotic Alignment on Dynamic Changes in Spinal Cord Compression and Neurological Status in Cervical Spondylotic Myelopathy: A Radiological Analysis Involving Kinematic CT Myelography and Multi-Modal Spinal Cord Evoked Potentials

Article

Oct 2020
SPINE

Study design: A retrospective study of prospectively collected data. Objective: This study aimed to examine how radiological parameters affect dynamic changes in the cross-sectional area of the spinal cord (CSA) in cervical spondylotic myelopathy (CSM) patients and how they correlate with the severity of myelopathy, by evaluating multi-modal spinal cord evoked potentials (SCEPs). Summary of background data: Appropriate assessments of dynamic factors should reveal hidden spinal cord compression and provide useful information for choosing surgical procedures. Methods: Seventy-nine CSM patients were enrolled. They were examined with kinematic CT myelography (CTM), and the spinal levels responsible for their CSM were determined via SCEP examinations. The C2-7 angle, C2-7 range of motion, and percentage of slip were measured on the midsagittal view during flexion and extension, and the CSA was measured on the axial view in each neck position using kinematic CTM. The patients who exhibited the smallest CSA values during extension and flexion were classified into Groups E and F, respectively. Results: Fifty-two (65.8%) and 27 (34.2%) cases were included in Groups E and F, respectively. The preoperative JOA score did not differ significantly between the groups; however, the preoperative lower-limb JOA score of Group F was significantly lower than that of Group E (2.24 ± 0.82 vs. 2.83 ± 1.09, P = 0.016). In the multiple logistic regression analysis, a small C2-7 angle during extension (β=5 degrees, odds ratio: 0.69, 95%CI: 0.54-0.90) and the slip percentage during flexion (β=5%, odds ratio: 1.42, 95%CI: 1.09-1.85) were identified as significant predictors of belonging to Group F. Conclusion: Exhibiting more severe spinal cord compression during neck flexion was associated with a small C2-7 angle and anterior spondylolisthesis. The neurological status of the patients in Group F was characterized by severe lower limb dysfunction because of a disturbed blood supply to the anterior column. Level of evidence: 4.

Vertebral Body Sliding Osteotomy for Cervical Myelopathy With Rigid Kyphosis

Article

Full-text available

Sep 2020

Cervical spondylotic myelopathy is surgically demanding when associated with rigid kyphosis. Posterior surgery cannot restore cervical lordosis, and adequate decompression is not possible with rigid kyphosis. Vertebral body sliding osteotomy (VBSO) is a safe and novel technique for anterior decompression in patients with multilevel cervical spondylotic myelopathy. It is safe in terms of dural tear, pseudarthrosis, and graft dislodgement, which are demonstrated at high rates in anterior cervical corpectomy and fusion. In addition, VBSO is a powerful method for restoring cervical lordosis through multilevel anterior cervical discectomy and fusion above and below the osteotomy level. It may be a feasible treatment option for patients with cervical spondylotic myelopathy and kyphotic deformity. This is a technical note and literature review that describes the procedures involved in VBSO.

Degenerative cervical myelopathy — update and future directions

Article

Jan 2020

Degenerative cervical myelopathy (DCM) is the leading cause of spinal cord dysfunction in adults worldwide. DCM encompasses various acquired (age-related) and congenital pathologies related to degeneration of the cervical spinal column, including hypertrophy and/or calcification of the ligaments, intervertebral discs and osseous tissues. These pathologies narrow the spinal canal, leading to chronic spinal cord compression and disability. Owing to the ageing population, rates of DCM are increasing. Expeditious diagnosis and treatment of DCM are needed to avoid permanent disability. Over the past 10 years, advances in basic science and in translational and clinical research have improved our understanding of the pathophysiology of DCM and helped delineate evidence-based practices for diagnosis and treatment. Surgical decompression is recommended for moderate and severe DCM; the best strategy for mild myelopathy remains unclear. Next-generation quantitative microstructural MRI and neurophysiological recordings promise to enable quantification of spinal cord tissue damage and help predict clinical outcomes. Here, we provide a comprehensive, evidence-based review of DCM, including its definition, epidemiology, pathophysiology, clinical presentation, diagnosis and differential diagnosis, and non-operative and operative management. With this Review, we aim to equip physicians across broad disciplines with the knowledge necessary to make a timely diagnosis of DCM, recognize the clinical features that influence management and identify when urgent surgical intervention is warranted.

Decreased choline acetyltransferase activity in the murine spinal cord motoneurons under chronic mechanical compression

Article

Full-text available

Dec 1997
SPINAL CORD

The tiptoe-walking Yoshimura (twy) mouse is a model of chronic spinal cord compression caused by ossification of intraspinal ligaments. Choline acetyltransferase (CAT), which is known to be a specific marker of cholinergic neurons, best reflects spinal motoneuron function. Changes in CAT immunoreactivity following chronic spinal cord compression in twy mice were investigated quantitatively in order to elucidate spinal motoneuron functional changes according to the degree and direction of compression. Thirty 24-week-old twy mice were used in this study. They were divided into three groups according to the direction of spinal cord compression (anterior, posterior, and lateral) and the CAT immunoreactivities in whole sections of their upper cervical spinal cords were investigated quantitatively using a fluorescence microphotometry system. The lateral compression group showed histological spinal motoneuron atrophy and loss on the compressed, but not the non-compressed, side. Spinal motoneuron atrophy and loss were observed when the severity of spinal canal stenosis due to the ossified lesion, expressed as the occupation rate, was 30% or more, but the spinal motoneurons appeared normal when it was below 30%. The CAT immunofluorescence intensity of the anterior horn showed a linear negative correlation with the degree of canal stenosis. When the occupation rate was below 20%, the CAT immunofluorescence intensities in the anterior horns of the compression and control groups did not differ significantly. The CAT immunofluorescence intensity of twy mice with occupation rates of 20% or more were significantly lower than that of those with occupation rates below 20%. Furthermore, the CAT immunofluorescence intensity was significantly lower on the compressed than the non-compressed side of the lateral compression group. Thus, our findings indicate that an occupation rate of about 20% may be the critical level for functional changes in the spinal motoneurons.

Experimental cervical myelopathy: Effects of ischemia and compression of the canine cervical spinal cord

Article

Aug 1975
J NEUROSURG

The authors report experiments designed to test the effect of regional ischemia induced by selective vascular ligations and anterior compression of the cervical cord at two adjacent segments (C-4, C-5) in the same dog. They conclude that local ischemia of the cervical cord, caused by local deformation, when superimposed on a regional reduction in spinal cord blood flow, accounts for the myelopathy of cervical spondylosis whether produced experimentally in animals or occurring naturally in man.

Neurofibromatosis of the cervical spine. A report of eight cases

Article

Aug 1992

Eight patients with neurofibromatosis presented with symptoms of cervical spine involvement over a period of 17 years, five of them within the second decade of life. The symptoms included neurological deficit in five, a neck mass in four, and deformity in three; only two complained of pain. Osteolysis of vertebral bodies with kyphosis of more than 90 degrees was the most common radiological feature. Posterior fusion failed in the one patient in whom it was performed. Good results were achieved by anterior fusion, alone, or combined with posterior fusion. Surgical complications included one death in a patient with a malignant neurofibroma, and one case of transient neurological deterioration.

Congenital kyphosis: Its natural history and treatment as observed in a study of one hundred and thirty patients

Article

Apr 1973

The three types, Type I (absence of vertebral bodies), Type II (failure of segmentation), and Type III (both), were seen in all sites in the spine, but paraplegia only occurred in unstable Type I lesions (six of twenty-four untreated), some with only moderate kyphosis, and without rapid progression. Without treatment, progression of the kyphos was the rule, averaging 7 degrees per year (thirty patients) and reaching a maximum during the adolescent growth spurt. Brace treatment was ineffective and forty-four patients had surgery. Pseudarthrosis in posterior fusions occurred in half the patients (fifteen of twenty-eight) and in only two of sixteen with combined anteroposterior fusions. Correction with or without Harrington apparatus with posterior fusions before the age of three is the recommended treatment. Where an angulation of over 50 degrees was present, anterior fusion was preferred.

Congenital kyphoscoliosis

Article

Jul 1973
Isr J Med Sci

J.I.P. James

The blood supply of the spinal cord. A critical vascular zone in spinal surgery

Article

Jun 1974

G F Dommisse

1. A high incidence of paraplegia following operations for the correction of severe scoliosis in adults led to an investigation of the normal blood supply of the human spinal cord. 2. This entailed three methods of study: micro-dissection of the vessels of the spinal cord in thirty-five cadavers; radiological measurements of the spinal canal in fifty healthy subjects; and a study of the macerated spinal column in six adult cadavers. 3. The blood supply of the spinal cord is shown to be least rich, and the spinal canal narrowest, from the T.4 to approximately the T.9 vertebral level. This is named the critical vascular zone of the spinal cord, the zone in which interference with the circulation is most likely to result in paraplegia.

Neurofibromatosis with paraplegia. Report of eight cases

Article

Aug 1969

Microvasculature of the human spinal cord

Article

Sep 1971
J NEUROSURG

Ian M. Turnbull

The regional differences in spinal microvasculature are outlined from microangiographic examination of the human spinal cord. Five to eight central arteries arise from each centimeter length of the anterior spinal artery in the cervical region, two to five in the thoracic region, and five to twelve in the lumbosacral region. The central arteries in the cervical and lumbar cord in addition to being more numerous are of larger caliber than those in the thoracic cord. Terminal arterioles do not interconnect within the spinal cord but give rise to interlocking capillary networks, which are more numerous in the gray than in the white matter. Arteries in the lateral columns are elongated with flattening of the spinal cord due to a space-occupying lesion. Correlation of the distortion of the small vessels with various types of spinal cord displacement is described.

Effects of Mechanical Stresses on the Spinal Cord in Cervical Spondylosis

Article

Aug 1966
J NEUROSURG

Neurologic Deficits Secondary to Spinal Deformity: A Review of the Literature and Report of 43 Cases

Article

Jul 1980

Forty-three cases of neurologic complications of untreated spinal deformities are reviewed. Kyphosis, averaging 95 degrees, was present in all but one patient. The most common deformity was a congenital kyphosis, present in 17 patients. The complication was more common in males, in the presence of thoracic deformities, and in the second decade. Treatment consisted of anterior spinal cord decompression in 25 patients, laminectomy in ten, Capener decompression in six, correction and fusion in five, and Hyndman-Schneider decompression in three. Laminectomy gave the worst results; six of ten patients who received this treatment showed deterioration. Anterior cord decompression gave the best results, with 16 of 25 showing improvement. A treatment plan for this complication is proposed. A plea for prevention is made, as it is far preferable to avoid this dreaded complication by early fusion of kyphotic problems.

A new breed of mouse showing multiple osteochondral lesions - twy mouse

Article

Feb 1981
Ryumachi Ryumachi

In Japan, a new breed of mouse showing multiple osteochondral lesions was discovered and was named the twy mouse (tiptoe walking-Yoshimura). This mouse line is characterized by tiptoe walking, stiffness of the vertebral column and limb joints, and later motor paresis. Calcification and ossification bridging adjacent vertebral bodies are seen in association with degeneration and destruction of the intervertebral discs. In limb joints, destruction of articular cartilage and synovial cell proliferation with or without inflammatory cell infiltration are observed. Calcification in and around the joint capsule is also noticed. Serum calcium level is within normal limits. These characteristics are inherited through an autosomal recessive single gene. This may be a useful model simulating various human diseases including ankylosing spondylitis, osteoarthritis and others.

Experimental chronic compressive cervical myelopathy

Article

Nov 1993
J NEUROSURG

A canine model simulating both cervical spondylosis and its results in delayed progressive myelopathy is presented. This model allowed control of compression, an ongoing assessment of neurological deficits, and evaluation using diagnostic images, frequent electrophysiological tests, local blood flow measurements, and postmortem histological examinations. Subclinical cervical cord compression was achieved in 14 dogs by placing a Teflon washer posteriorly and a Teflon screw anteriorly, producing an average of 29% stenosis of the spinal canal. Four dogs undergoing sham operations were designated as controls. Twelve of the animals undergoing compression developed delayed and progressive clinical signs of myelopathy, with a mean latent period to onset of myelopathy of 7 months. Spinal cord blood flow studies using the hydrogen clearance method showed a significant transient increase in blood flow immediately after compression and a decrease before sacrifice. Somatosensory evoked potential studies indicated progressive deterioration during the period of compression. Magnetic resonance images revealed intramedullary changes. Histological studies showed abnormalities overwhelmingly within the gray matter, including changes in vascular morphology, loss of large motor neurons, necrosis, and cavitation. Axonal degeneration and obvious demyelination were rarely seen. The most profound morphological changes occurred at the site of greatest compression. It is proposed that a momentary arrest of microcirculation occurs during extension of the neck because of loss of the reserve space in the compromised spinal canal. This microcirculatory disturbance is predominant in the watershed area of the cord and mainly affects the highly vulnerable anterior horn cells, leading to neuronal death, necrosis, and eventual cavitation at the junction of the dorsal and anterior horns. Additional supportive evidence of this hypothesis was derived from the literature.

Spinal cord compression studies: I. Experimental Techniques to Produce Acute and Gradual Compression

Article

Jan 1954
Arch Neurol Psychiatr

THERE IS much controversy over the proper treatment of acute and chronic spinal cord compression. Not everyone agrees, for instance, on the best time to operate in cases of acute compression of the spinal cord or cauda equina, or whether to operate at all. Some of the signs and symptoms accompanying these lesions, moreover, are perplexing, and even misleading. Kahn¹ has called attention to the primary lateral sclerosis syndrome resulting from anterior spinal cord compression. Only recently, indeed, several well-known neurologists made a diagnosis of primary lateral sclerosis in a quadriplegic woman. At operation, however, one of us (I. M. T.) removed a ventrally placed meningioma from the cervical portion of her spinal cord. On occasion, also, "neoplasms may simulate subacute combined degeneration of the spinal cord."² In an effort to throw light on these problems, we have submitted them to experimental analysis in laboratory animals. The project

Spinal kyphosis causes demyelination and neuronal loss in the spinal cord: a new model of kyphotic deformity using juvenile Japanese small game fowls

Abstract

No full-text available

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