Incidence of Neuraxial Abnormalities Is Approximately 8% Among Patients With Adolescent Idiopathic Scoliosis: A Meta-analysis

What imaging does my AIS patient need? A multi-group survey of provider preferences

INTRODUCTION

Adolescent idiopathic scoliosis (AIS) is a common diagnosis managed by pediatric orthopedic surgeons with nonoperative radiographic monitoring representing a cornerstone of treatment. Differences in practices and techniques for obtaining radiographic studies contribute to variation, cost of care, and hamper data aggregation. We surveyed several large organizations dedicated to children's orthopedics or scoliosis care to obtain a consensus for radiographic evaluation of AIS.

METHODS

A REDCap-based survey was developed across four institutions and beta-tested by staff and fellows from a single institution. The finalized survey was distributed to members of POSNA, PSSG, and SOSORT, and shared on social media. Participants were asked to rank the importance of various datapoints in radiographic assessment of the spinal deformity, skeletal maturity, and study indications during initial, subsequent, preoperative, and final office visits for AIS. Response rate for the overall group was 26%.

RESULTS

Cobb angle was considered the most important (> 94%) radiographic index across all time points. For positioning, 46% of respondents favored arms bent touching clavicles as the ideal positioning for X-rays, and another 24% favored arms down with palms forward (Table 2). The majority of respondents obtain lateral X-rays at the first visit (99%) and at the preoperative visit (70%). At the preoperative visit, sagittal contour (86%), apex location (85%), and Lenke classification (73%) were considered important factors to record. Flexibility studies are primarily obtained at the preoperative visit (89%) and 81% of respondents prefer bending films as the flexibility technique of choice. Regarding measures of skeletal maturity, Sanders bone age was considered to be the most important by over 70% of respondents across initial, subsequent, preoperative and brace wean visits (Fig. 2). MRIs were obtained routinely by 34% of respondents and only when the patient had a concerning symptom or finding for 67% of respondents.

CONCLUSIONS

Despite large variations in radiographic examination of AIS, large areas of agreement were found. It is important to establish standards for positioning patients, evaluating skeletal maturity, and obtaining assessments including lateral views, flexibility studies, and advanced imaging. Establishing common practices for radiographic evaluation of AIS will allow for less variation in care and for critical questions to be answered through registry formation and large multicenter data collection.

SIGNIFICANCE

This study establishes current practitioner opinion on the radiographic evaluation of the AIS patient. Minimum data sets are useful for data aggregation and answering research questions in the face of data variability.

LEVEL OF EVIDENCE

Level V.

Role of spinal MRI for pre-operative work up in patients with adolescent idiopathic scoliosis: a retrospective case study and narrative review

INTRODUCTION

There remains variability in the acquisition of whole-spine MRI prior to surgical correction in patients with adolescent idiopathic scoliosis (AIS). In this study, we take a retrospective look at the clinical impact of uniformly obtaining spinal MRI on all patients with a diagnosis of AIS.

METHODS

Three hundred thirty four patients with presumed AIS who underwent surgery between 2017 and 2022 were identified; 283 of these patients who were asymptomatic and had a preoperative MRI in the database were included. We investigated radiographic, demographic, and clinical risk factors for the presence of neural axis anomalies. Radiologists' reports were reviewed to determine the level of the conus medullaris and the presence of any intra-spinal dysraphisms. The utility of known risk factors for neural axis anomalies and the utility of MRI identifying anomalies on clinical decision-making, intra-operative neuromonitoring (IONM) alerts, and postoperative neurologic insult in asymptomatic AIS patients were investigated.

RESULTS

There were 283 patients with a mean age of 14.1 years, 67 males (22.6%) and 26 (9.2%) left-sided thoracic curves. MRI identified nine patients with central cord dilations, four patients with low cerebellar tonsils, four patients with Chiari Malformations, five patients with low-lying conus, one patient with a tethered cord, and five patients with arachnoid cysts. Six (2.1%) of the 283 patients underwent a neurosurgical intervention and 3 (50%) of the 6 went on to have IONM alerts. Eighteen (6.4%) of the 283 patients had IONM alerts and 5 (28%) of the 18 had neural axis anomalies. None of the patients with IONM alerts had a permanent neurologic deficit post-operatively.

CONCLUSION

In asymptomatic patients presumed to have AIS, 9.9% had a neuro-axis anomaly, 2.1% needed a neurosurgical intervention, and 6.4% of the patients had an IONM alert. We did not find known risk factors for identifying neural axis anomalies to have statistically significant application in asymptomatic AIS patients. Presence of neuroaxis anomalies increased the chance of having IONM alerts, however, we were unable to demonstrate if neurosurgical interventions in these patients with anomalies were preventative for IONM alerts or have statistically significant protection against clinical complications.

The morphological discrepancy of neuromuscular junctions between bilateral paraspinal muscles in patients with adolescent idiopathic scoliosis: A quantitative immunofluorescence assay

Introduction

Prior studies suggested that neuromuscular factors might be involved in the pathogenesis of adolescent idiopathic scoliosis (AIS). The neuromuscular junction (NMJ) is the important pivot where the nervous system interacts with muscle fibers, but it has not been well characterized in the paraspinal muscles of AIS. This study aims to perform the quantitative morphological analysis of NMJs from paraspinal muscles of AIS.

Methods

AIS patients who received surgery in our center were prospectively enrolled. Meanwhile, age-matched congenital scoliosis (CS) and non-scoliosis patients were also included as controls. Fresh samples of paraspinal muscles were harvested intraoperatively. NMJs were immunolabeled using different antibodies to reveal pre-synaptic neuronal architecture and post-synaptic motor endplates. A confocal microscope was used to acquire z-stack projections of NMJs images. Then, NMJs images were analyzed on maximum intensity projections using ImageJ software. The morphology of NMJs was quantitatively measured by a standardized 'NMJ-morph' workflow. A total of 21 variables were measured and compared between different groups.

Results

A total of 15 AIS patients, 10 CS patients and 5 normal controls were enrolled initially. For AIS group, NMJs in the convex side of paraspinal muscles demonstrated obviously decreased overlap when compared with the concave side (34.27% ± 8.09% vs. 48.11% ± 10.31%, p = 0.0036). However, no variables showed statistical difference between both sides of paraspinal muscles in CS patients. In contrast with non-scoliosis controls, both sides of paraspinal muscles in AIS patients demonstrated significantly smaller muscle bundle diameters.

Conclusions

This study first elucidated the morphological features of NMJs from paraspinal muscles of AIS patients. The NMJs in the convex side showed smaller overlap for AIS patients, but no difference was found in CS. This proved further evidence that neuromuscular factors might contribute to the mechanisms of AIS and could be considered as a novel potential therapeutic target for the treatment of progressive AIS.

The hindbrain and cortico-reticular pathway in adolescent idiopathic scoliosis

AIM

To characterise the corticoreticular pathway (CRP) in a case-control cohort of adolescent idiopathic scoliosis (AIS) patients using high-resolution slice-accelerated readout-segmented echo-planar diffusion tensor imaging (DTI) to enhance the discrimination of small brainstem nuclei in comparison to automated whole-brain volumetry and tractography and their clinical correlates.

MATERIALS AND METHODS

Thirty-four participants (16 AIS patients, 18 healthy controls) underwent clinical and orthopaedic assessments and brain magnetic resonance imaging (MRI) on a 3 T MRI machine. Automated whole-brain volume-based morphometry, tract-based spatial statistics analysis, and manual CRP tractography by two independent raters were performed. Intra-rater and inter-rater agreement of DTI metrics from CRP tractography were assessed by intraclass correlation coefficient. Normalised structural brain volumes and DTI metrics were compared between groups using Student's t-tests. Linear correlation analysis between imaging parameters and clinical scores was also performed.

RESULTS

AIS patients demonstrated a significantly larger pons volume compared to controls (p=0.006). Significant inter-side CRP differences in mean (p=0.02) and axial diffusivity (p=0.01) were found in patients only. Asymmetry in CRP fractional anisotropy significantly correlated with the Cobb angle (p=0.03).

CONCLUSION

Relative pontine hypertrophy and asymmetry in CRP DTI metrics suggest central supranuclear inter-hemispheric imbalance in AIS, and support the role of the CRP in axial muscle tone. Longitudinal evaluation of CRP DTI metrics in the prediction of AIS progression may be clinically relevant.

The use of MRI in the study of patients with idiopathic scoliosis: a systematic review of the literature

Objective. To analyze the frequency of hidden neuraxial pathology in idiopathic scoliosis (IS), to substantiate the need for MRI in IS and to identify promising areas for the use of MRI in the examination of patients with IS.Material and Methods. The literature review was carried out using the PubMed and Google Scholar databases. Of the 780 papers on the research topic, 65 were selected after removing duplicates and checking for inclusion/exclusion criteria. As a result, 49 original studies were included in the analysis. Level of evidence – II.Results. According to modern literature, the main direction of using MRI in idiopathic scoliosis is the search for predictors of latent pathology of the spinal cord and craniovertebral junction. The frequency of neuraxial pathology in idiopathic scoliosis is 8 % for adolescent IS and 16 % for early IS. The main predictors of neuraxial pathology are male sex, early age of deformity onset, left-sided thoracic curve and thoracic hyperkyphosis. MRI in IS may be a useful addition to radiological diagnostic methods to identify risk factors and to study degenerative changes in the spine.Conclusion. MRI of the spine should be performed in the early stages of IS to detect latent spinal cord tethering. In type I Chiari anomalies, there is a possibility that early neurosurgery can prevent the development of scoliosis. The main signs of latent neuraxial pathology in IS are early progression of spinal deformity, left-sided thoracic curve, male gender and thoracic kyphosis over 40° according to Cobb.MRI can be used as an effective non-invasive tool in research aimed at identifying risk factors for IS, including helping to track early degeneration of intervertebral discs.

The Prevalence of Hip Pathologies in Adolescent Idiopathic Scoliosis

Background

Adolescent idiopathic scoliosis (AIS) is the most common form of abnormal spine curvature observed in patients age 10 to 18. Typically characterized by shoulder height and waistline asymmetry, AIS may drive uneven distribution of force in the hips, leading to increased rates of concurrent hip diagnoses. The relationship between AIS and concurrent hip diagnoses is underexplored in the literature, and to date, there has been little research comparing rates of hip diagnoses between patients with AIS and those unaffected.

Purpose

Assess differences in rates and clusters of hip diagnoses between patients with AIS and those unaffected.

Study design

Retrospective review of Healthcare Cost and Utilization Project's (HCUP) Nationwide Inpatient Sample (NIS).

Patient sample

224,504 weighted inpatient discharges.

Outcome measures

Rates of hip diagnoses.

Methods

Patients in the NIS database (2005-2013) ages 10-18 years were isolated. Patients were grouped by those diagnosed with AIS (ICD-9: 737.30) and those unaffected. Patient groups were propensity score matched (PSM) for age. Means comparison tests assessed differences in demographic, comorbidity, and diagnosis profiles between patient groups for corresponding age categories. ICD-9 codes were used to identify specific hip diagnoses.

Results

Following PSM, 24,656 AIS and 24,656 unaffected patients were included. The AIS patient group was comprised of more females (66% vs 59%) and had lower rates of obesity (2.4% vs 3.5%, both p < 0.001). Overall, 1.1% of patients had at least one hip diagnosis: congenital deformity (0.31%), developmental dysplasia (0.24%), recurrent dislocation (0.18%), isolated dislocation (0.09%), osteonecrosis (0.08%), osteochondrosis (0.07%), acquired deformity (0.03%), and osteoarthritis (0.02%). AIS patients had lower rates of osteonecrosis (0.04% vs 0.12%, p = 0.003), but higher rates of all other hip diagnoses, including dysplasia (0.41% vs 0.07%, p < 0.001), recurrent dislocation (0.32% vs 0.03%, p < 0.001), isolated dislocation (0.13% vs 0.06%, p < 0.001), and osteoarthritis (0.04% vs 0.01%, p = 0.084. Co-occurrences of hip diagnoses were relatively rare, with 0.03% patients having more than one hip diagnosis. Rates of co-occurring hip diagnoses did not differ between AIS and unaffected groups (0.04% vs 0.02%, p = 0.225).

Conclusions

Compared to unaffected patients of similar ages, patients with AIS had higher overall rates of hip diagnoses, including dysplasia and recurrent dislocation. A higher trend of precocious osteoarthritis was also observed at a higher rate in AIS patients, although this difference was not statistically significant. Our results present an argument for surgical realignment in the coronal and sagittal planes to neutralize asymmetrical forces in the hips, and suggest the need for increased awareness and clinical screening for hip-related disorders in AIS patients.

Level of Evidence

III.

Diagnosis and treatment of Chiari malformation and syringomyelia in adults: international consensus document

BACKGROUND

Syringomyelia and Chiari malformation are classified as rare diseases on Orphanet, but international guidelines on diagnostic criteria and case definition are missing.

AIM OF THE STUDY

to reach a consensus among international experts on controversial issues in diagnosis and treatment of Chiari 1 malformation and syringomyelia in adults.

METHODS

A multidisciplinary panel of the Chiari and Syringomyelia Consortium (4 neurosurgeons, 2 neurologists, 1 neuroradiologist, 1 pediatric neurologist) appointed an international Jury of experts to elaborate a consensus document. After an evidence-based review and further discussions, 63 draft statements grouped in 4 domains (definition and classification/planning/surgery/isolated syringomyelia) were formulated. A Jury of 32 experts in the field of diagnosis and treatment of Chiari and syringomyelia and patient representatives were invited to take part in a three-round Delphi process. The Jury received a structured questionnaire containing the 63 statements, each to be voted on a 4-point Likert-type scale and commented. Statements with agreement <75% were revised and entered round 2. Round 3 was face-to-face, during the Chiari Consensus Conference (Milan, November 2019).

RESULTS

Thirty-one out of 32 Jury members (6 neurologists, 4 neuroradiologists, 19 neurosurgeons, and 2 patient association representatives) participated in the consensus. After round 2, a consensus was reached on 57/63 statements (90.5%). The six difficult statements were revised and voted in round 3, and the whole set of statements was further discussed and approved.

CONCLUSIONS

The consensus document consists of 63 statements which benefited from expert discussion and fine-tuning, serving clinicians and researchers following adults with Chiari and syringomyelia.

Scoliosis with Chiari I malformation without associated syringomyelia

PURPOSE

Many patients with presumed idiopathic scoliosis are found to have Chiari I malformation (CM-I) on MRI. The objective of this study is to report on scoliosis progression in CM-I with no syringomyelia.

METHODS

A retrospective review of patients with scoliosis and CM-I was conducted from 1997 to 2015. Patients with syringomyelia and/or non-idiopathic scoliosis were excluded. Clinical and radiographic characteristics were recorded at presentation and latest follow-up. CM-I was defined as the cerebellar tonsil extending 5 mm or more below the foramen magnum on MRI.

RESULTS

Thirty-two patients (72% female) with a mean age of 11 years (range 1-16) at scoliosis diagnosis were included. The average initial curve was 30.3° ± SD 16.3. The mean initial Chiari size was 9.6 mm SD ± 4.0. Fifteen (46.9%) experienced Chiari-related symptoms, and three (9%) patients underwent Posterior Fossa Decompression (PFD) to treat these symptoms. 10 (31%) patients went on to fusion, progressing on average 13.6° (95% CI 1.6-25.6°). No association was detected between decompression and either curve progression or fusion (p = 0.46, 0.60). For those who did not undergo fusion, curve magnitude progressed on average 1.0° (95% CI - 4.0 to 5.9°). There was no association between age, Chiari size, presence of symptoms, initial curve shape, or bracing treatment and fusion.

CONCLUSION

Patients with CM-I and scoliosis may not require surgical treatment, including PFD and fusion. Scoliosis curvature stabilized in the non-surgical population at an average progression of 1.0°. These results suggest that CM-I with no syringomyelia has minimal effect on scoliosis progression.

Clinical Trial Registry Use in Orthopaedic Surgery Systematic Reviews

BACKGROUND

Results from systematic reviews and meta-analyses, which have the highest level of evidence (Level I), often drive clinical decision-making and health policy. Often, unpublished trial data are omitted from systematic reviews, raising concerns about the extent of the reliability and validity of results that have been drawn from systematic reviews. We aimed to determine the extent to which systematic review authors include searches of clinical trial registries for unpublished data when conducting systematic reviews in orthopaedic surgery.

METHODS

Systematic reviews and/or meta-analyses were gathered from the top 5 orthopaedic surgery journals based on the h5-index from Google Scholar Metrics. Systematic reviews that had been published in the Cochrane Database of Systematic Reviews, which requires the inclusion of a clinical trial registry search, served as controls. For the primary outcome, each systematic review from the top 5 orthopaedic journals was screened to determine whether the authors of each study searched for unpublished data in clinical trial registries. We then compared the rate of registry searches with those in the control group. For the secondary analysis, a search of ClinicalTrials.gov was performed for unpublished trial data for 100 randomized systematic reviews.

RESULTS

All 38 of the Cochrane systematic reviews (100%) included clinical trial registry searches, while the top 5 orthopaedic journals had only 31 of 480 studies (6.5%) that looked at clinical trial registries. The secondary analysis yielded 59 of 100 systematic review articles (59.0%) that could have included unpublished clinical trial data from ≥1 studies to their sample.

CONCLUSIONS

Systematic reviews that have been published in the top orthopaedic surgery journals seldom included a search for unpublished clinical trial data.

CLINICAL RELEVANCE

The exclusion of clinical trial registry searches potentially contributes to publication bias within the orthopaedic literature. Moving forward, systematic review authors should include clinical trial registry searches for unpublished clinical trial data to provide the most accurate representation of the available evidence for systematic reviews and meta-analyses.

Controversies with nonoperative management for adolescent idiopathic scoliosis: Study from the APSS Scoliosis Focus Group

PURPOSE

To determine consensus among Asia-Pacific surgeons regarding nonoperative management for adolescent idiopathic scoliosis (AIS).

METHODS

An online REDCap questionnaire was circulated to surgeons in the Asia-Pacific region during the period of July 2019 to September 2019 to inquire about various components of nonoperative treatment for AIS. Aspects under study included access to screening, when MRIs were obtained, quality-of-life assessments used, role of scoliosis-specific exercises, bracing criteria, type of brace used, maturity parameters used, brace wear regimen, follow-up criteria, and how braces were weaned. Comparisons were made between middle-high income and low-income countries, and experience with nonoperative treatment.

RESULTS

A total of 103 responses were collected. About half (52.4%) of the responders had scoliosis screening programs and were particularly situated in middle-high income countries. Up to 34% obtained MRIs for all cases, while most would obtain MRIs for neurological problems. The brace criteria were highly variable and was usually based on menarche status (74.7%), age (59%), and Risser staging (92.8%). Up to 52.4% of surgeons elected to brace patients with large curves before offering surgery. Only 28% of responders utilized CAD-CAM techniques for brace fabrication and most (76.8%) still utilized negative molds. There were no standardized criteria for brace weaning.

CONCLUSION

There are highly variable practices related to nonoperative treatment for AIS and may be related to availability of resources in certain countries. Relative consensus was achieved for when MRI should be obtained and an acceptable brace compliance should be more than 16 hours a day.

Magnetic resonance imaging effectiveness in adolescent idiopathic scoliosis

OBJECTIVE

To assess the effectiveness of preoperative magnetic resonance imaging (MRI) in adolescent idiopathic scoliosis (AIS) patients with unremarkable history and physical examination.

METHODS

The imaging data of consecutive patients with presumed AIS treated with a posterior spinal fusion between 2010 and 2016 were reviewed. The presence of traditional risk factors, atypical curve patterns, and its association with relevant abnormalities on MRI were investigated. The number needed to diagnose (NND) and the number needed to misdiagnose (NNM) were calculated to measure MRI effectiveness.

RESULTS

A total of 198 consecutive patients were identified and divided according to the presence of MRI findings. Both groups predominantly consisted of females, with a mean age of 15 years and right thoracic curvature. Neural axis abnormalities were detected in 25 patients, and the groups had a similar proportion of atypical findings, as curve magnitude, thoracic kyphosis, curve direction, and sex. The NND was 7.9 patients and NNM was 66 patients, meaning that the management was changed before the spine fusion in 12% of patients with neural axis abnormalities. None of the traditional risk factors could predict a higher incidence of neural axis abnormalities in asymptomatic AIS patients.

CONCLUSION

Traditional risk factors may not be predictive of patients with a higher risk of changes in MRI. Both NND and NNM are representations easily understood by clinicians. Using these indexes to define if a patient should be submitted for additional imaging tests may facilitate the decision of using MRI as a preoperative screening tool in AIS patients.

LEVEL OF EVIDENCE

Level II.

Pattern of Syringomyelia in Presumed Idiopathic and Congenital Scoliosis

Study Design

Retrospective study.

Purpose

This study was undertaken to compare the patterns of syringomyelia in patients with presumed idiopathic and congenital scoliosis.

Overview of Literature

The incidence of neuraxial anomalies presenting as idiopathic scoliosis ranges from 2% to 14%; the common ones are idiopathic syringomyelia (IS) and Chiari malformation type 1 (CM1) with syringomyelia. Some authors have speculated that scoliosis is caused by the asymmetrical compression of anterior horn cells by a syrinx, which causes an imbalance of the trunk musculature. In congenital scoliosis, syringomyelia is the second commonest cord anomaly, and the deformity progression depends upon the underlying vertebral abnormality, the location of the abnormality, and the age of patient, and is independent of the intraspinal anomaly.

Methods

We analyzed the radiological records of 44 consecutive patients with scoliosis and syringomyelia. Of these 44 patients, 13 had IS, 12 had CM1, and 19 had congenital scoliosis. The radiographs were evaluated to determine the curve magnitude, sagittal alignment, side of convexity, and type of vertebral anomaly, if any. T1- and T2-weighted magnetic resonance imaging of the whole spine was analyzed to determine the presence of craniovertebral anomalies, syrinx length, syrinx diameter, and syrinx-cord ratio (SCR).

Results

The frequency of left convex curves was 26.1%, with no significant differences across the three groups. The mean length of the syrinx was 7.2±4.9 vertebral levels, and the mean SCR was 0.39±0.2. The mean syrinx length was significantly higher in patients with CM1 and IS, compared to patients with congenital scoliosis. The mean SCR was highest in patients with CM1. In congenital scoliosis, syringomyelia was seen most frequently in patients with a failure of formation, and 63.2% had concomitant cord anomalies.

Conclusions

Syrinxes were smaller in size and length in patients with congenital scoliosis, and are distinct from those seen in IS and CM1.

Incidence of intraspinal abnormalities in congenital scoliosis: a systematic review and meta-analysis

Objective

This is the first systematic review and meta-analysis on the overall incidence of intraspinal abnormalities in patients with congenital scoliosis (CS) and potential influencing factors.

Methods

We searched three large electronic databases (PubMed, EMBASE, and Cochrane Library) for potentially relevant studies. The quality of the included studies was assessed independently by two authors using the Methodological Index for Non-Randomized Studies (MINORS) criteria. Data on the number of CS patients, number of CS patients with intraspinal abnormalities, sex of the patients, and CS types were extracted from the included studies. R software was used to pool and analyze all the extracted data.

Results

This meta-analysis included 10 articles, and 671 of 1863 CS patients undergoing magnetic resonance imaging (MRI) examinations were identified to have intraspinal abnormalities. The overall incidence of intraspinal abnormalities in the patients with CS was 37% (95% CI, 29–45%). Diastematomyelia was the most common intraspinal abnormality and was detected in 45.60% of the patients with intraspinal abnormalities (306/671). The remaining intraspinal abnormalities included syringomyelia (273/671, 40.69%), tethered cord (190/671, 28.32%), low conus (58/671, 8.64%), intraspinal mass (39/671, 5.81%), Chiari malformation (32/671, 4.77%), fatty filum (27/671, 4.02%), spina bifida (occulta excluded) (17/671, 2.53%), tumor (17/671, 2.53%), cyst (12/671, 1.79%), syringomyelus (4/671, 0.60%), dural ectasia (1/671, 0.15%), and undiagnosed cord MRI hyperintensity (1/671, 0.15%). The patient’s sex and CS type were not factors that affected the incidence of intraspinal abnormalities in CS patients (all P > 0.05).

Conclusions

This meta-analysis revealed that the overall incidence of intraspinal abnormalities detected by MRI in CS patients was 37%. Diastematomyelia was the most common intraspinal abnormality. The patient’s sex and CS type were not factors that affected the incidence of intraspinal abnormalities in CS patients.

The Role of MRI in Children With Congenital Limb Deficiencies With Associated Scoliosis

BACKGROUND

The association of scoliosis and congenital limb deficiency has been well described. However, the incidence of neural axis abnormalities in this population is not known. The ability to assess the neural axis by physical examination may be limited in patients with a limb deficiency. Although mobility of the spine is important for all children, it can be especially so in children with a limb deficiency. As spinal fusion in children with limb deficiency potentially has more functional impact, detecting reversible forms of scoliosis seems particularly important.

METHODS

Retrospective review of children treated at 1 institution between 1990 and 2017 with both a diagnosis of a congenital limb deficiency, upper or lower, and scoliosis. Children were excluded if they had any neurological difference on history or physical examination, if they had sacral agenesis or spina bifida, or if their limb deficiency was related to trauma or early amniotic rupture sequence.

RESULTS

Twenty-four children were identified, 11 with lower extremity deficiency, 14 with upper extremity deficiency with 1 having both. Fifteen children demonstrated neural axis abnormalities, 6 (40%) required neurosurgery. Five (45%) of 11 lower extremity deficiency children had MRI findings, 3 of these needing neurosurgery. Of the 14 upper extremity deficiency children, 10 had MRI changes, and 3 required neurosurgery. Eight children with congenital scoliosis, 5 had MRI findings, with 4 children requiring neurosurgery. The other 16 children had scoliosis without vertebral abnormalities, 10 had MRI findings, and 2 required neurosurgery.

CONCLUSIONS

There is a high incidence of neural axis abnormalities (63%) in children with congenital limb deficiencies and scoliosis. A large portion of these require neurosurgical intervention. MRI should be considered soon after presentation in this population of children.

LEVEL OF EVIDENCE

Level IV.

DESIGN

Retrospective cohort.

Surgical Scoliosis Correction in Chiari-I Malformation with Syringomyelia Versus Idiopathic Syringomyelia

BACKGROUND

Both patients with Chiari-I malformation (CIM) with syringomyelia and those with idiopathic syringomyelia (ISm) have a syrinx and can have scoliosis as well. However, there is no literature regarding differences between CIM and ISm in terms of radiographic outcomes and surgical complications after posterior fusion, to our knowledge. The aim of the present study was to compare radiographic features, clinical outcomes, and surgical complications after posterior spinal fusion between patients with CIM-associated scoliosis and those with ISm-associated scoliosis.

METHODS

One hundred and twenty patients with syringomyelia-associated scoliosis were retrospectively analyzed. Twenty-one patients with scoliosis secondary to CIM were enrolled and matched by sex, age, and the Cobb angle of the scoliotic curve with 21 patients with scoliosis secondary to ISm. All patients underwent 1-stage posterior fusion surgery. Coronal and sagittal radiographic parameters were evaluated before surgery, immediately after surgery, and at the final follow-up (at least 2 years). We also collected data regarding syringeal features, neurological deficits, intraoperative neuromonitoring, and complications.

RESULTS

Sex, age, preoperative coronal/sagittal scoliosis parameters, and neurological deficits were similar between the matched CIM and ISm groups. On average, the CIM group had a longer syrinx (12.3 ± 3.6 versus 8.9 ± 4.5 vertebral levels, p = 0.010) than the ISm group. The CIM and ISm groups showed similar correction rates for primary curves (70.9% ± 10.6% versus 69.5% ± 16.3%, p = 0.739). There were no significant differences in coronal/sagittal correction, intraoperative neuromonitoring abnormalities, surgical complications, or Scoliosis Research Society-22 questionnaire scores between the 2 groups.

CONCLUSIONS

Despite matched demographic and scoliotic coronal parameters, patients with CIM had longer syrinxes compared with patients with ISm. One-stage posterior fusion achieved comparable clinical and radiographic outcomes for both CIM- and ISm-associated scoliosis without significant differences in neurological complications.

LEVEL OF EVIDENCE

Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Continuous Hypodynamic Change of Cerebrospinal Fluid Flow as A Potential Factor Working for Experimental Scoliotic Formation

Scoliosis is often associated with syringomyelia (SM). As an important role in SM formation, the influence from abnormal cerebrospinal fluid (CSF) flow is still unclear to scoliosis. The aim of this experimental work is to explore the connection between CSF flow and scoliosis through imaging and histological analysis on the basis of a kaolin-induced scoliotic rabbit model. For imaging observation, in 40 kaolin-induced rabbits by C7 spinal cord injection, through pre- and postoperative MRI and radiography, CSF flow and scoliosis formation were detected at consecutive phases. According to the final formation of scoliosis until postoperative week 12, the kaolin-induced rabbits were divided into 2 groups. Through comparing the 2 groups, the relationship between the changes of CSF flow velocity and scoliosis formation were reviewed and analyzed. For histological observation, another 20 kaolin-induced rabbits were used for consecutive histological observations of spinal cord at postoperative 3-day, 2-week, 4-week and 6-week. After kaolin-induction, abnormal spinal coronal curve was observed from postoperative week 6 in the 37 survived rabbits. At postoperative week 12, scoliosis formation was detected in 73.0% kaolin-induced rabbits and the mean Cobb angle was 27.4°. From the comparison between scoliotic and non-scoliotic groups, the difference of the velocities of CSF flow was more obviously from postoperative week 4 to 12, especially after week 6. In the scoliotic group, the peak velocity of CSF flow was diseased gradually following scoliosis formation after induction. Moreover, the decrease of the peak velocities of CSF flow from preoperation to postoperative 12 weeks (ΔVmax), including up-flow (ΔVUmax) and down-flow (ΔVDmax), were positively correlated to the final scoliotic Cobb angle (P < 0.01). Through histological observation at different phases, the distinctive pathological changes of the spinal cord included early inflammatory reaction, adhesion and blockage in the subarachnoid space and the central canal, perivascular space enlargement, central canal expansion, which suggested the CSF flow being blocked by multiple ways after kaolin-induction. In conclusion, experimental scoliosis can be successfully induced by intraspinal kaolin injection. In this model, continuous hypodynamic change of CSF flow was correlated to the formation of scoliosis, which could be an important factor of scoliotic pathogenesis being explored furtherly.

Selective thoracic fusion for adolescent thoracic scoliosis secondary to Chiari I malformation: a comparison between the left and the right curves

PURPOSE

The aim of this study was to compare the clinical outcomes of selective thoracic fusion in the surgical treatment of Chiari malformation type I (CMI) adolescents with different curve patterns.

METHODS

Sixty-three CMI patients with left thoracic curve (LTC) and 63 age- and curve-magnitude-matched CMI patients with right thoracic curve (RTC) were recruited. Selective thoracic fusion was performed for two groups. The coronal and sagittal parameters including the thoracic and lumbar Cobb angle, apical vertebral translation, trunk shift, thoracic kyphosis (TK), lumbar lordosis and sagittal vertical axis were measured before surgery, immediately postoperative and at the final follow-up. The accuracy of pedicle screw placement between both groups was also compared.

RESULTS

All preoperative radiographic parameters were matched in both groups except for TK (LTC group 40.1° vs. RTC group 23.0°, P = 0.021). The immediately postoperative spontaneous correction of the lumbar curve was 56.9% in LTC group, which was remarkably lower than in RTC patients (67.9%). Patients with LTC were found to have obviously increased trunk shift than those with RTC (15.1 mm vs. 8.0 mm, P = 0.038). At the final follow-up, the correction of the thoracic curve was comparable between the two groups (59.9% vs. 62.6%, P = 0.610). The rate of the pedicle screw perforations was similar between both groups.

CONCLUSIONS

Patients with LTC and RTC can both be successfully corrected through selective thoracic fusion with a promising long-term surgical outcome. CMI patients with RTC tend to have a better spontaneous correction of the lumbar curve after surgery. These slides can be retrieved under Electronic Supplementary Material.

Clinical manifestations and radiological characteristics in patients with idiopathic syringomyelia and scoliosis

PURPOSE

To clarify the clinical manifestation and radiological characteristics of idiopathic syringomyelia (IS) and to investigate the relationship between syrinx and scoliotic curves in IS-related scoliosis patients.

METHODS

Fifty-five patients with IS and scoliosis were identified and reviewed retrospectively from June 2009 to December 2016. Radiographic features of syrinx, scoliosis and clinical manifestations of neurological deficits were collected. The syrinx/cord (S/C) ratio was defined as the anteroposterior diameter of syrinx divided by the diameter of spinal cord at the same level. Patients were classified into two groups, the thoracic group (T group, apex vertebra located from T2 to intervertebral disk of T11-T12) and the thoracolumbar/lumbar group (TL/L group, apex vertebra located from T12 to L5).

RESULTS

There was no correlation between the radiological features of idiopathic syrinx and scoliotic curve parameters. The TL/L group had a lower level of most caudal extent (13.7 compared with 10.6, P = 0.029) and lower level of largest S/C ratio (12.0 compared with 8.7, P = 0.016) than that in T group. The deviated side of syrinx was not coincident with major curve convexity (27.2% concordance rate, P = 0.522) or dominant side of neurological deficit (16.3% concordance rate, P = 0.212).

CONCLUSIONS

Patients with major curves located on the thoracolumbar or lumbar spine had a much lower caudal extent and lower level of greatest S/C ratio compared to patients with major curves located on the thoracic spine. No significant relationships were detected between syrinx features, scoliotic curve parameters and neurological deficits. These slides can be retrieved under Electronic Supplementary Material.