Preoperative MRI analysis of patients with idiopathic scoliosis: a prospective study

A multipurpose, adolescent idiopathic scoliosis-specific, short MRI protocol: A feasibility study in volunteers

INTRODUCTION

Visualization of scoliosis typically requires ionizing radiation (radiography and CT) to visualize bony anatomy. MRI is often additionally performed to screen for neural axis abnormalities. We propose a 14-minutes radiation-free scoliosis-specific MRI protocol, which combines MRI and MRI-based synthetic CT images to visualize soft and osseous structures in one examination. We assess the ability of the protocol to visualize landmarks needed to detect 3D patho-anatomical changes, screen for neural axis abnormalities, and perform surgical planning and navigation.

METHODS

18 adult volunteers were scanned on 1.5 T MR-scanner using 3D T2-weighted and synthetic CT sequences. A predefined checklist of relevant landmarks was used for the parameter assessment by three readers. Parameters included Cobb angles, rotation, torsion, segmental height, area and centroids of Nucleus Pulposus and Intervertebral Disc. Precision, reliability and agreement between the readers measurements were evaluated.

RESULTS

91 % of Likert-based questions scored ≥ 4, indicating moderate to high confidence. Precision of 3D dot positioning was 1.0 mm. Precision of angle measurement was 0.6° (ICC 0.98). Precision of vertebral and IVD height measurements was 0.4 mm (ICC 0.99). Precision of area measurement for NP was 8 mm2 (ICC 0.55) and for IVD 18 mm2 (ICC 0.62) for IVD. Precision of centroid measurement for NP was 1.3 mm (ICC 0.88-0.92) and for IVD 1.1 mm (ICC 0.88-91).

CONCLUSIONS

The proposed MRI protocol with synthetic CT reconstructions, has high precision, reliability and agreement between the readers for multiple scoliosis-specific measurements. It can be used to study scoliosis etiopathogenesis and to assess 3D spinal morphology.

Adolescent Idiopathic Scoliosis Minimum Data Set: Towards Standardization of Data Elements in History and Physical Examination

INTRODUCTION

Nonoperative care represents a cornerstone of adolescent idiopathic scoliosis (AIS) management, although no consensus exists for a minimal data set. We aimed to determine a consensus in critical data points to obtain during clinical AIS visits.

METHODS

A REDCap-based survey was distributed to Pediatric Orthopedic Society of America (POSNA), Pediatric Spine Study Group (PSSG), and International Society on Scoliosis Orthopedic and Rehabilitation Treatment (SOSORT). Respondents ranked the importance of data points in history, physical examination, and bracing during AIS visits.  Results: One hundred eighty-one responses were received (26% response rate), of which 86% were physicians and 14% were allied health professionals. About 80% of respondents worked at pediatric hospitals or pediatric spaces within adult hospitals, and 82% were academic, with the majority (57%) seeing 150+ unique AIS patients annually. Most respondents recommended six-month follow-up for patients under observation (60%) and bracing (54%). Most respondents (75%) considered family history and pain important (69%), with the majority (69%) asking about pain at every visit. Across all time points, Adam's forward bend test, shoulder level, sagittal contour, trunk shift, and curve stiffness were all considered critically important (>60%). At the first visit, scapular prominence, leg lengths, motor and neurological examination, gait, and iliac crest height were also viewed as critical. At the preoperative visit, motor strength and scapular prominence should also be documented. About 39% of respondents use heat sensors to monitor bracing compliance, and average brace wear since the prior visit was considered the most important (85%) compliance data point.

CONCLUSIONS

This study establishes recommendations for a 19-item minimum data set for clinical AIS evaluation, including history, physical exam, and bracing, to allow for future multicenter registry-based studies.

Spontaneous Unilateral Chiari I Secondary to Acquired Tonsillar Hypertrophy/Pseudomass With Syringomyelia in a Juvenile With Progressive Scoliosis

Chiari type 1 malformation (CM-1) is a structural defect of the central nervous system in which part of the cerebellar tonsils descend below the level of the foramen magnum, sometimes with associated syringomyelia. Although Chiari malformations were traditionally believed to be congenital, several cases of acquired CM-1 with syringomyelia have been reported. Usually associated with repeat lumbar puncture, increased intracranial pressure, and craniocephalic disproportion, CM-1 in the absence of an underlying etiology is rare. We report a rare case of spontaneous idiopathic tonsillar hypertrophy causing unilateral CM-1 with syringomyelia associated with progressive scoliosis in a juvenile with a previously normal neonatal MRI brain and no known underlying pathology. A 9-year-old boy was found to have scoliosis at a routine well-child visit with progression indicated on radiographs 4 months later. Whole spine MRI was performed and showed a new CM-1 with globular, mass-like configuration of the descended right tonsil with otherwise normal tonsillar characteristics. Surgical decompression via suboccipital craniectomy and C1 laminectomy with duraplasty was performed with improvement illustrated on repeat MRI 3 months postoperatively. This rare case emphasizes the importance of routine MRI spine early in select patients with idiopathic scoliosis and illustrates the favorable outcomes noted after decompressive craniectomy.

7.7% Prevalence of neural axis abnormalities on routine magnetic resonance imaging in patients with presumed adolescent idiopathic scoliosis scheduled for spine surgery: a consecutive single surgeon retrospective cohort of 182 patients

PURPOSE

The purpose of this study was to use a Delphi analysis to identify a clinically relevant threshold for the prevalence of neural axis abnormalities (NAAs) that would warrant routine preoperative screening.

METHODS

A panel of experienced physicians specializing in pediatric spine surgery, pediatric neurosurgery, and pediatric neuroradiology was formed to establish consensus using a Delphi process to identify a minimum prevalence of NAAs that would initiate the implementation of preoperative MRIs as standard of care. Following the Delphi analysis, patients scheduled for PSF (Posterior Spinal Fusion) from 2010 to 2018 were retrospectively identified. Patients were included based on the following criteria: (1) 10-18 years old at time of MRI (inclusive), (2) AIS diagnosis prior to preoperative MRI (no concerning curve pattern, rate of progression, or neurologic signs/symptoms to suggest alternative diagnosis to AIS), and (3) standard preoperative MRI of the cervical, thoracic, and lumbar spine undergone. The prevalence of NAAs on preoperative MRI was recorded for all patients.

RESULTS

There were 182 eligible patients. 14 had NAAs on MRI. The prevalence of NAAs was 7.7% [95% CI 4.27-12.57%]. This prevalence was significantly [p < 0.0001] higher than the clinically relevant threshold of 1.3% established by the Delphi panel. Of the 14 patients with NAAs noted on preoperative MRI, neurosurgical intervention was recommended for 4 patients, 2.2% [95% CI 0.6-5.5%] of the total cohort.

CONCLUSIONS

Delphi panelists reported a low tolerance for NAAs among patients undergoing PSF for presumed AIS. Group consensus recommended routine screening should be implemented if the prevalence of NAAs is greater than 1.3%. The prevalence of NAAs in our cohort as well as related studies was significantly higher than this threshold.

LEVEL OF EVIDENCE

Diagnostic-level III.

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.

Entire-spine Magnetic Resonance Imaging Findings and Costs in Children With Presumed Adolescent Idiopathic Scoliosis

BACKGROUND

Patients with adolescent idiopathic scoliosis (AIS) are commonly monitored for curve progression with spinal radiographs; however, the utility of magnetic resonance imaging (MRI) screening is unclear. The purpose of this study was to assess the findings of screening MRI for patients with a nonsurgical curve size ordered during routine clinical care and compare them with MRI ordered for patients with large curves as part of preoperative screening.

METHODS

All consecutive patients with presumed AIS who underwent entire-spine MRI with a presumed diagnosis of idiopathic scoliosis at a single institution between 2017 and 2019 were retrospectively reviewed. Patients were stratified based on MRI indication into the following groups: preoperative evaluation, pain, neurological symptoms, abnormal radiographic curve appearance, rapidly progressive curve, and other. Neural axis abnormalities recorded included concern for tethered spinal cord, syringomyelia, and Chiari malformation. The MRI findings of preoperative patients with large curves were compared with all other patients. The number needed to diagnose (NND) a neurological finding was calculated in patients whose MRIs were ordered during routine clinical care. The amount charged for each patient undergoing entire-spine MRI was determined by review of our institution's Financial Decision Support system.

RESULTS

There were 344 patients included in this study with 214 (62%) MRIs performed for preoperative evaluation. Although MRI abnormalities were found in 49% of patients, only 7.0% (24/344) demonstrated neural axis abnormalities with no difference between preoperative and other indications (P=0.37). For patients with nonsurgical curves undergoing MRI due to a complaint of back pain (n=28), there were no neural axis abnormalities, and a lower rate of disk herniation/degenerative changes detected compared with preoperative MRI (3.6% vs. 18%, P=0.06). Among the 15 patients undergoing MRI for a neurological concern, 1 had a neural axis abnormality that required surgical detethering. The NND for MRI to detect a neural axis abnormality that potentially required neurosurgical intervention in nonpreoperative patients with a neurological concern was 34.4. The average cost for MRI was $17,816 (range: $2601 to $22,411) with a total cost of $2,368,439 for nonsurgical curves.

CONCLUSIONS

Entire-spine MRI for nonpreoperative indications including pain, abnormal radiographic curve appearance, and rapid curve progression has minimal utility for patients with AIS. For patients with neurological complaints, the NND a potentially treatment-altering finding with MRI is 34.4.

LEVEL OF EVIDENCE

Level II-diagnostic.

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.

Cross-sectional analysis and trend of vertebral and associated anomalies in Chinese congenital scoliosis population: a retrospective study of one thousand, two hundred and eighty nine surgical cases from 2010 to 2019

PURPOSE

The objective of this article is to report associated anomaly incidences of a large CS cohort and analyze interrelationships among vertebral anomaly types and associated abnormalities.

METHODS

We retrospectively searched and extracted medical records of 1289 CS inpatients surgically treated in our institute from January 2010 to December 2019. All patients have taken spine X-ray, CT, MRI, echocardiogram, urogenital ultrasound, and systemic physical examination. We analyzed information on demographics, CS types, and associated anomalies.

RESULTS

CS type was found to be 49.1% for failure of formation (FF), 19.5% for failure of segmentation (FS), and 31.4% for mixed defects (MD). Intraspinal defects were found in 29.4% patients (16.0% for FF, 45.4% for FS, 40.5% for MD), cardiac in 13.7% (12.3% for FF, 14.3% for FS, 15.6% for MD), genitourinary in 5.8% (4.1% for FF, 6.0% for FS, 8.4% for MD), gastrointestinal in 3.6% (4.7% for FF, 1.6% for FS, 3.0% for MD), and musculoskeletal in 16.4% (10.3% for FF, 19.9% for FS, 23.7% for MD). The intraspinal and musculoskeletal defect incidences were significantly higher in patients with failure of segmentation and mixed defects. We also observed a decreasing trend for intraspinal and musculoskeletal defect incidences as well as a tendency for more failure of formation and less failure of segmentation from 2010 to 2019.

CONCLUSIONS

The intraspinal and musculoskeletal defect incidences were higher in patients with failure of segmentation and mixed defects. Strong interrelationships were found between intraspinal and musculoskeletal defects and among cardiovascular, genitourinary, and gastrointestinal defects. From 2010 to 2019, the proportion of patients with failure of formation increased significantly, causing a decrease in the intraspinal and musculoskeletal defect incidences over time. Female sex, failure of segmentation, and mixed defects could be considered risk factors for more associated anomalies in CS individuals, which would help surgeons in medical management and prenatal consultation.

Spinal-Shortening Process Positively Improves Associated Syringomyelia in Patients with Scoliosis After Single-Stage Spinal Correction

OBJECTIVE

Single-stage spinal correction without previous neurosurgical intervention has been attempted in patients with scoliosis associated with syringomyelia (SM). However, evidence to demonstrate its potential influence on associated SM from direct spinal correction is still lacking. The aim of the present study was to explore the role of spinal shortening in the prognosis of SM-associated scoliosis after single-stage spinal correction without previous neurosurgical intervention.

METHODS

Patients with SM-associated scoliosis without previous neurological intervention, who had undergone posterior direct instrumental correction (PDIC) without osteotomy and posterior vertebral column resection (PVCR) at a single center, were selected for comparative analysis. The basic demographic and pre- and postoperative imaging data of the spinal deformity and SM at the final follow-up were compared separately for the 2 different spinal correction procedures.

RESULTS

A total of 23 patients were included in the final analysis: 13 had undergone PDIC and 10 had undergone PVCR. The mean follow-up period was 6.2 years (range, 5-9 years). At the final follow-up, the mean corrective rate of scoliosis and kyphosis was 65.7% and 48.4%, respectively. Obvious SM reduction was achieved in 11 patients (47.8%), with an average reduction of 37.3%. No patient experienced neurologic deterioration or had required further neurosurgical intervention for SM during follow-up. The patients who had undergone PVCR had had much more severe scoliosis (98.8° vs. 60.5°; P = 0.000) and kyphosis (74.8° vs. 43.6°; P = 0.032). Moreover, 80.0% of the patients who had undergone PVCR had experienced obvious SM improvement compared with 23.1% of those who had undergone PDIC (P = 0.007).

CONCLUSIONS

The reduction of spinal cord tension is an important factor influencing SM improvement. As the most powerful spinal-shortening osteotomy, PVCR can effectively correct severe spinal deformities and improve associated SM. Single-stage posterior spinal correction can be a potential choice for selected patients with scoliosis and untreated SM using strict inclusion criteria, which will not only achieve safe spinal correction but could also steadily improve and stabilize SM.

Preoperative and Postoperative Imaging in Idiopathic Scoliosis: What the Surgeon Wants to Know

The term idiopathic scoliosis covers a broad spectrum of spinal deformities in the pediatric population without an underlying congenital anomaly of the spine. Depending on the age of presentation, it has both characteristic clinical and imaging features and a different prognosis. The radiologist should provide the surgeon with critical information to assess the degree of deformity and eventually plan surgery. Thoracic deformities and lung volume must also be part of the preoperative assessment. Imaging has a critical role in postsurgical follow-up and in surgical complications. This review highlights the importance of common terminology and measurement methods to avoid incongruences. The different imaging modalities are discussed with their indications and limitations. We pay special attention to imaging modalities that can help the surgeon assess skeletal maturation reliably and thus predict the prognosis of scoliosis. Radiation protection and the risk of cumulative radiation exposure in these patients is emphasized.

Incidence and significance of findings on spinal MRIs in a paediatric population with spinal column complaints

PURPOSE

We sought to identify correlations between working diagnosis, surgeon indication for obtaining spinal MRI and positive MRI findings in paediatric patients presenting with spinal disorders or complaints.

METHODS

Surgeons recorded their primary indication for ordering a spinal MRI in 385 consecutive patients. We compared radiologist-reported positive MRI findings with surgeon response, indication, working diagnosis and patient demographics.

RESULTS

The most common surgeon-stated indications were pain (70) and coronal curve characteristics (63). Radiologists reported 137 (36%) normal and 248 (64%) abnormal MRIs. In total, 58% of abnormal reports (145) did not elicit a therapeutic or investigative response, which we characterized as 'clinically inconsequential'. In all, 42 of 268 (16%) presumed idiopathic scoliosis patients had intradural pathology noted on MRI.Younger age (10.3 years versus 12.0 years) was the only significant demographic difference between patients with or without intradural pathology. Surgeon indication 'curve magnitude at presentation' was associated with intradural abnormality identification. However, average Cobb angles between patients with or without an intradural abnormality was not significantly different (39° versus 37°, respectively). Back pain without neurological signs or symptoms was a negative predictor of intradural pathology.

CONCLUSION

Radiologists reported a high frequency of abnormalities on MRI (64%), but 58% of those were deemed clinically inconsequential. Patients with MRI abnormalities were two years' younger than those with a normal or inconsequential MRI. 'Curve magnitude at presentation' in presumed idiopathic scoliosis patients was the only predictor of intrathecal pathology. 'Pain' was the only indication significantly associated with clinically inconsequential findings on MRI.

LEVEL OF EVIDENCE

III.

The rate of intraspinal problems and clinical evaluation of scoliosis: A cross-sectional, descriptive study

Objectives

This study aims to define the chronological, angular, and topographic classes in presumed idiopathic scoliosis and to investigate the frequency of generalized joint hypermobility, pain, neurological deficit, ankle deformity, Risser grade, and magnetic resonance imaging (MRI) findings in these patients.

Patients and methods

This cross-sectional, descriptive study included a total of 36 patients (11 males, 25 females; mean age 13.4±4.6 years; range, 6 to 24 years) with idiopathic scoliosis between January 2015 and January 2019. Data including age, sex, complaint of pain, generalized joint hypermobility (based on Beighton score), neurological deficit, ankle deformity, and definition of scoliosis were recorded. Chronological, angular, and topographic classification were carried out. The Risser grade and MRI findings were noted.

Results

Of all patients, 30 (83.3%) were idiopathic, five (13.9%) were neuromuscular, and one (2.8%) was congenital scoliosis based on MRI findings. Of 13 (36.1%) spine MRI scans, six (46.2%) were intraspinal anomalies, four were syringomyelia (30.8%), one was Chiari type 1 malformation (7.7%), and one was hemivertebrae with diastematomyelia (7.7%). The highest rates of classes according to chronological, angular, and topographical classifications of idiopathic scoliosis were adolescent (17/30, 56.7%), low angular (24/30, 80.0%), and lumbar scoliosis (15/30, 50.0%), respectively. Ten patients (33.3%) complained of pain, while 23 patients (76.7%) had no neurological deficit and seven (23.3%) had hypoesthesia. Seventeen patients (56.7%) had generalized joint hypermobility.

Conclusion

Idiopathic scoliosis with non-severe spinal deformity may present with intraspinal neural axis abnormalities, even when it is neurologically intact. Based on our study results, it seems to be useful to consider whole spine MRI for the evaluation of thoracic and lumbar scoliosis.

MRI utilization and rates of abnormal pretreatment MRI findings in early-onset scoliosis: review of a global cohort

STUDY DESIGN

Retrospective review OBJECTIVES: To report the frequency of pretreatment magnetic resonance imaging (MRI) utilization and rates and types of intra-spinal abnormalities identified on MRI in patients with early-onset scoliosis (EOS). MRI can help identify spinal cord abnormalities in patients with EOS.

METHODS

We reviewed data from patients enrolled from 1993-2018 in an international EOS registry. Patients with incomplete/unverifiable data and those with spinal deformities secondary to infection or tumor were excluded, leaving 1343 patients for analysis. Demographic characteristics, pretreatment major curve magnitude, treatment type, and MRI findings were analyzed. Patients were categorized by EOS type (congenital, idiopathic, neuromuscular, syndromic), pretreatment MRI utilization, and presence of intra-spinal abnormality on MRI. Univariate testing and multivariate logistic regression were performed to identify demographic, radiographic, and clinical predictors of MRI utilization and abnormal MRI findings.

RESULTS

MRI was used in 836 patients (62%). Pretreatment MRI utilization rates ranged from 42% in neuromuscular EOS to 74% in congenital EOS. Prevalence of abnormal MRI findings was 24% overall, ranging from 13% in patients with idiopathic EOS to 39% in neuromuscular EOS. Compared with white/Caucasian patients, Asian/Asian-American patients had higher odds of MRI utilization and abnormal MRI findings. Treatment type, pretreatment major curve magnitude, age at MRI, and age at treatment were not associated with abnormal MRI findings. Overall, 249 abnormalities were identified in 197 patients. The most common findings were syrinx and tethered cord. Syrinx with Chiari malformation was the most frequent combination of abnormal findings.

CONCLUSION

In the two-thirds of patients who underwent MRI before EOS treatment, findings were abnormal in 24%. EOS type and race/ethnicity were associated with both MRI utilization and abnormal findings. The most frequent abnormalities were syrinx and tethered cord, and the type of abnormalities appeared to differ by EOS type.

LEVEL OF EVIDENCE

Prognostic, Level III.

Cervical Abnormalities in Severe Spinal Deformity: A 10-year MRI Review

Objective

To investigate the incidence of cervical anomalies (CA), including cervical intraspinal neural axis abnormalities (CIINAA) and/or cervical osseous abnormalities (COA), and the clinical relevance in severe spinal deformities (SSD) at a single center.

Methods

A retrospective study of SSD admitted for spinal surgery from January 2003 to January 2015 was conducted at a single center. Inclusion criteria: patients who present with coronal Cobb over 90° (and/or sagittal cobb ≥90°); and patients with complete imaging and clinical data preoperatively. Exclusion criteria: ankylosing spondylitis, adult onset scoliosis, scoliosis secondary to bone destruction. There were 108 SSD patients who fulfilled the criteria in this research (41 males and 67 females). The mean age of the patients was 18.1 ± 2.7 years (range, 10–45 years). The clinical and radiological data of these patients were reviewed to identify CA and to analyze the relationship between clinical and radiographic characteristics in the population of SSD.

Results

The major curves of scoliosis and segmental kyphosis were 109.1° ± 24.7° and 91.2° ± 29.1°. Cervical abnormalities were detected in 56 patients (51.85%) with 9 different CA, including 28 patients (25.9%) with 6 different COA, 21 patients (19.4%) with 3 different CIINAA, and 7 patients (6.5%) with a combination of COA and cervical intraspinal neural axis abnormalities (CINAA). Basilar invagination and Klippel–Feil syndrome were the most frequent COA. Syringomyelia was the most frequent CINAA. SSD with COA in upper vertebral levels (UVL) had a higher incidence of CINAA than those in subaxial vertebral levels (SVL) (P = 0.024) and SSD with multiple COA (mCOA) in UVL had a higher incidence of CINAA than those with single COA (sCOA) (P = 0.029). In the present study, 83.9% of the SSD with CA were asymptomatic.

Conclusion

The incidence of CA in SSD was 51.85%, with most presenting with intact neurologic status. As the diversity of COA increased, we found a higher incidence of CINAA, especially in UVL.

Clinical Relevance of Preoperative MRI in Adolescent Idiopathic Scoliosis: Is Hydromyelia a Predictive Factor of Intraoperative Electrophysiological Monitoring Alterations?

STUDY DESIGN

This was a prospective cohort study.

OBJECTIVES

The main objectives of this study were to evaluate the prevalence and clinical relevance of neuroaxial anomalies in adolescent idiopathic scoliosis (AIS) patients as well as to evaluate different clinical and radiologic variables as potential predictors of the presence of a magnetic resonance imaging (MRI) abnormality.

SUMMARY OF BACKGROUND DATA

The usefulness of preoperative magnetic resonance imaging in AIS is still debated in the literature as well as the clinical relevance of the neuroaxial anomalies detected.

MATERIALS AND METHODS

We performed an analysis on 88 patients affected by AIS with normal neurological examination undergoing a posterior arthrodesis intervention. Patients were stratified according to the presence and type of neuroaxial abnormalities and were compared by age, sex, Risser grading, Lenke curve type, coronal and sagittal curve parameters, presence of alterations at intraoperative neuromonitoring, and "pain" and "function" scores at the SRS-22 test.

RESULTS

Neuroaxial abnormalities were reported in 23 patients (26.14%): 14 hydromyelias, 7 syringomyelias, 1 case of Chiari I syndrome, and 1 case of spinal ependymoma. Age, sex, Risser grading, curve type, and coronal and sagittal curve parameters did not differ between normal patients and patients with any neuroaxial abnormality. Alterations of motor-evoked potential/somatosensory-evoked potential monitoring during surgery were reported in 23 patients; the difference in their incidence between normal (20%) and hydromyelia (64%) patients was significant (P<0.01). In evaluating the subareas of the SRS-22 test, we found that the "function" scores differed significantly by comparing normal (21.5±1.6) and hydromyelia (20.4±1.8) patients (P<0.05).

CONCLUSIONS

The prevalence of neuroaxial abnormalities in AIS patients is relatively high, but we could not identify any definitive clinical or radiologic predictor of their presence. Hydromyelia was correlated with intraoperative motor-evoked potential/somatosensory-evoked potential electrophysiological alterations.

Incidence of Intraspinal and Extraspinal MRI Abnormalities in Patients With Adolescent Idiopathic Scoliosis

STUDY DESIGN

Retrospective study with follow-up.

OBJECTIVES

The purpose of this study was to determine the incidence of intraspinal and extraspinal MRI abnormalities in a consecutive series of patients with adolescent idiopathic scoliosis (AIS) and to describe the evaluation and management of these abnormalities.

SUMMARY OF BACKGROUND DATA

Indications for preoperative magnetic resonance imaging (MRI) in patients with AIS remain controversial. Previous studies have reported a wide range of abnormality rates; however, the majority of these studies focus on a nonconsecutive series of patients, and none of these studies report the incidence of extraspinal abnormalities.

METHODS

We studied a consecutive series of patients with AIS managed with spinal deformity surgery. All patients underwent a routine neural axis MRI prior to surgery. MRI reports were reviewed, and intraspinal and extraspinal abnormalities were recorded. Additional chart review and follow-up was performed to determine the rates of evaluation and management for these abnormalities. Descriptive statistics were used to describe the incidence and types of abnormalities, as well as the rates of evaluation and management.

RESULTS

This study included a consecutive series of 259 patients with AIS. MRI abnormalities were noted in 115 patients (44%). After excluding patients with degenerative changes, MRI abnormalities were noted in 64 patients (25%). The incidence of Chiari malformation was 4.2% and syringomyelia was 5%. Extraspinal abnormalities were noted in 10% of patients, and these findings ranged from benign cysts to malignant soft tissue tumor. Approximately 10% of patients needed additional evaluation because of their preoperative MRI findings, and 0.7% of patients required surgical management prior to spinal deformity surgery.

CONCLUSIONS

Significant MRI abnormalities were noted in patients with AIS, and some patients required further evaluation prior to surgery. Additional study including cost-effectiveness analysis is needed to better define the role of preoperative MRI in patients with AIS.

LEVEL OF EVIDENCE

Level II.

Neural Axis Abnormalities in Patients With Adolescent Idiopathic Scoliosis: Is Routine Magnetic Resonance Imaging Indicated Irrespective of Curve Severity?

Objective

Magnetic resonance imaging (MRI)-verified neural axis abnormalities (NAAs) have been described in adolescent idiopathic scoliosis (AIS), and several risk factors have been associated with the presence of NAAs in AIS patients. However, the clinical significance of these findings is unclear. The purpose of the present study was to determine the prevalence of NAAs in a large consecutive cohort of AIS patients and to evaluate the clinical significance of previously proposed risk factors.

Methods

We prospectively included AIS patients referred to a tertiary facility for evaluation. Full-spine MRI scans were performed on all included patients irrespective of curve magnitude or proposed treatment modality. MRI scans were prospectively analyzed by a neuroradiologist and the pathologic findings were confirmed by a second independent radiologist.

Results

NAA was observed in 34 of the 381 patients (8.9%): 32 patients had a syrinx, 1 patient had an arachnoid cyst, and 1 patient had a Chiari malformation. Four patients were referred for a neurosurgical evaluation but none received any neurosurgical treatment. No statistically significant difference was observed between the NAA and non-NAA groups in terms of sex, major curve size, thoracic kyphosis, left thoracic curve, curve convexity, curve progression, or level of pain (p>0.05).

Conclusion

In this prospective study examining the risk factors for NAA in AIS patients, we found that previously proposed risk factors could not predict the MRI outcomes. The finding of an NAA had no clinical implications and we do not support MRI scans as a routine diagnostic modality in all AIS patients.

Is the routine use of magnetic resonance imaging indicated in patients with scoliosis?

Background

To assess the reliability of the indicators for performing magnetic resonance imaging in patients with scoliosis and assess the incidence of neural axis anomalies in a population with scoliosis referred to a specialist centre.

Methods

A retrospective review of magnetic resonance imaging (MRI) reports of all patients under the age of 18 who underwent a pre-operative MRI for investigation of their scoliosis between 2009 and 2014 at a single institution was performed.

Results

There were 851 patients who underwent an MRI scan of their whole spine with a mean age of 14.08 years. There were 211 males and 640 females. One hundred and fourteen neural axis abnormalities (NAA) were identified. The presence of a left sided thoracic curve, a double thoracic curve, being male nor being diagnosed before the age of 10 were found to be statistically significant for the presence of a NAA. Furthermore, 2.34% of patients were also found to have an incidental finding (IF) of an extraspinal abnormality.

Conclusions

From our series, the reported indications for performing an MRI scan in the presence of scoliosis are not reliable for the presence of an underlying NAA. We have demonstrated that there is a number of intra and extra dural anomalies found on MRI without clinical symptoms and signs. This acts as normative information for this group.

Keywords

Scoliosis; magnetic resonance imaging (MRI); neural axis abnormalities (NAA); adolescent idiopathic scoliosis (AIS).

Prevalence and risk factors for neural axis anomalies in idiopathic scoliosis: a systematic review

BACKGROUND

There is ongoing controversy about the routine use of magnetic resonance imaging (MRI) preoperatively in patients with presumed idiopathic scoliosis (IS). Routine MRI can help identify possible causes for the deformity and detect anomalies that could complicate deformity surgery. However, routine MRI increases health-care costs significantly and may reveal mild variations from normal findings without clinical relevance, which can still lead to anxiety and influence decision-making.

PURPOSE

Given the necessity to make evidence-based decisions both in the light of quality of care and cost control, the aim of this review is to report the prevalence of neural axis anomalies in IS and to identify risk factors associated with these anomalies.

STUDY DESIGN

A systematic review was carried out.

METHODS

An electronic search of PubMed, Embase, Cochrane, and Cinahl until May 2017 was performed. Studies were assessed by two reviewers independently according to predetermined inclusion (MRI in presumed IS) and exclusion criteria (diagnosis other than IS).

RESULTS

Fifty-one studies were included comprising 8,622 patients. In 981 patients, anomalies were found, resulting in an overall prevalence of 11.4%. The prevalence was 10.5%, 9.0%, and 14.2% when screening was performed of all IS patients, preoperative patients, or patients with presumed risk factors. The prevalence of a syrinx (3.7%), an Arnold-Chiari malformation (3.0%), or a combination of both (2.5%) was highest. Less frequent diagnoses included tethered cord (0.6%), an incidental malignancy (0.3%), and split cord malformations (0.2%). Risk factors for intraspinal anomalies included early-onset scoliosis, male gender, atypical curves, thoracic kyphosis, and abnormal neurologic findings such as reflexes and sensation.

CONCLUSIONS

This systematic review shows that a significant number of patients have intraspinal anomalies on preoperative MRI in (presumed) IS. The prevalence of finding spinal axis abnormalities increases in preselected patient groups with specific risk factors.

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

BACKGROUND

Several studies have sought to address the role of routine preoperative MRI in patients with adolescent idiopathic scoliosis (AIS) undergoing deformity correction. Despite similar results regarding the prevalence of neuraxial anomalies detected on MRI, published conclusions conflict and give opposing recommendations. Lack of consensus has led to important variations in use of MRI before spinal surgery for patients with AIS.

QUESTIONS/PURPOSES

This systematic review and meta-analysis of studies about patients with AIS evaluated (1) the overall proportion of neuraxial abnormalities; (2) the patient factors and curve characteristics that may be associated with abnormalities; and (3) the proportion of patients who underwent neurosurgical intervention before scoliosis surgery and the kinds of neuraxial lesions that were identified.

METHODS

We performed a search of four electronic databases (PubMed, EMBASE, CINAHL Plus, and SCOPUS) utilizing search terms related to routine MRI and AIS, yielding 206 articles. Studies included had at least 20 participants, patients with ages 11 to 21 years, and a Methodological Index for Non-Randomized Studies (MINORS) study quality score of 8 and 16 points for noncomparative and comparative studies, respectively. Non-English manuscripts, animal studies, and those that did not include patients with AIS solely were excluded. Eighteen articles with 4746 patients were included for analysis of the overall proportion of neuraxial abnormalities, 12 articles with 3028 patients for analysis by sex, eight articles with 1603 patients for right main thoracic curve, eight articles with 665 patients for a left main thoracic curve, and 13 articles with 3063 patients and 230 (7.5%) abnormalities for number of neurosurgical interventions before scoliosis correction. The mean MINORS score for studies included was 14 (range, 10-20). Each study was analyzed for the proportion of patients identified with neuraxial abnormalities and associations with specific demographics. We determined the proportion of patients who underwent surgical interventions before scoliosis surgery as well as the types of neuraxial lesions identified. The articles were assessed for heterogeneity and publication bias. Because all groups were determined to be heterogeneous, a random-effects model was used for each group in this meta-analysis; with this analysis, an overlap of 95% confidence intervals suggests no difference at the p < 0.05 level, but this analytic approach does not provide p values.

RESULTS

The pooled proportion of neuraxial abnormalities detected on MRI was 8% (95% confidence interval [CI], 6%-12%). With the numbers available, we found no difference in the proportion of male and female patients with neuraxial abnormalities (18% [95% CI, 11%-29%] versus 9% [95% CI, 6%-12%], respectively). Likewise, there was no difference in the proportion of pooled neuraxial abnormalities in right and left curves (9% [95% CI, 6%-14%] versus 15% [95% CI, 5%-35%], respectively). In the subset of abnormalities analyzed for number of neurosurgical interventions before scoliosis correction, the pooled proportion showed that 33% (95% CI, 24%-43%) underwent neurosurgical intervention before deformity correction. The most common abnormalities of the 367 found on MRI were syringomyelia in 127 patients (35%), Arnold-Chiari Type 1 malformation with syrinx in 103 patients (28%), and isolated Arnold-Chiari Type 1 malformation in 91 patients (25%).

CONCLUSIONS

The proportion of patients with AIS who have neuraxial abnormalities is high (8%) and a large number undergo surgical intervention before scoliosis reconstruction. We did not find any particular demographic variables that indicated an increased risk of abnormality. Clinicians should consider advanced imaging before surgical intervention in the treatment of a patient with an idiopathic diagnosis. Preventable variables need to be identified by future studies to establish a better working treatment protocol for these patients.

LEVEL OF EVIDENCE

Level III, diagnostic study.

Relationship between thoracic kyphosis and neural axis abnormalities in patients with adolescent idiopathic scoliosis

PURPOSE

Previous studies have suggested an association between increased thoracic kyphosis and neural axis abnormalities in patients with adolescent idiopathic scoliosis (AIS). However, the basis for this finding is unclear, and this association has been mainly noted in retrospective studies on a non-consecutive series of patients. The purpose of this study was to assess the relationship between thoracic kyphosis and neural axis abnormalities in patients with AIS.

METHODS

We studied a consecutive series of AIS patients treated with spinal fusion. Thoracic kyphosis (T2 to T12) was measured from preoperative lateral radiographs. All patients underwent a spine magnetic resonance imaging (MRI) prior to surgery, and MRI reports were reviewed to determine the presence of neural axis abnormalities. Statistical analyses included descriptive statistics and chi-squared analysis.

RESULTS

This study included 210 patients with AIS. There were no significant differences in age or gender between patients with thoracic hypokyphosis (kyphosis < 20°), normal thoracic kyphosis (kyphosis 20° to 40°) and thoracic hyperkyphosis (kyphosis > 40°) (p > 0.05). Neural axis abnormalities were present in 17.9% of patients with thoracic hypokyphosis, 9.8% of patients with normal thoracic kyphosis and 13.6% of patients with thoracic hyperkyphosis (p = 0.60). There were no significant differences in rates of Chiari malformation, syrinx, intra-spinal masses and other central nervous system abnormalities between groups (p > 0.05).

CONCLUSIONS

Thoracic kyphosis was not associated with neural axis abnormalities in our consecutive series of patients with AIS. Increased thoracic kyphosis may not be a reliable indicator for the presence of neural axis abnormalities in patients with AIS.

LEVEL OF EVIDENCE

IV.

Scoliosis in Dandy-Walker syndrome: a case report and review of literature

This submission presents a case of scoliosis in a patient with established Dandy-Walker anomaly of the brain. A retrospective review of the patient's case notes was undertaken and the limited literature on this subject reviewed. The 13-year-old girl presented with a stiff right thoracic scoliosis typical of adolescent idiopathic scoliosis. The scoliotic segment also presented with significant lordosis. She had facial and truncal dysmorphism characteristic of Dandy-Walker complex and her brain images confirmed the diagnosis. She underwent scoliosis surgery by the posterior approach uneventfully. In conclusion scoliosis is hitherto unreported in the Dandy-Walker complex. The results of intervention appear satisfactory.

Should all paediatric patients with presumed idiopathic scoliosis undergo MRI screening for neuro-axial disease?

BACKGROUND

Idiopathic scoliosis is a relatively common childhood condition affecting 0.47-5.2% of the population. Traditional interventions focus on orthopaedic correction of the curve angle. There is a spectrum of patients with scoliosis who are found to have neuro-axial abnormality on full MRI of the spine, but not all surgeons request imaging in the absence of neurological symptoms. There is evidence to suggest that treatment of neuro-axial disease may improve scoliosis curve outcome. We therefore sought to estimate what proportion of patients with normal neurology and scoliosis are found to have neuro-axial abnormality on full MRI imaging of the spine, in particular Chiari malformation and syringomyelia.

RESULTS

Out of 11 identified studies consisting of 3372 paediatric patients (age < 18 years), mean weighted proportion demonstrates that 14.7% of patients with scoliosis (Cobb angle > 20°) and normal neurological examination will demonstrate a neuro-axial abnormality on full MRI imaging of the spine. Of patients, 8.3 and 8.4% were found to have Chiari malformation and syringomyelia, respectively.

CONCLUSIONS

Up to one in seven paediatric patients with scoliosis and normal neurological examination will demonstrate neuro-axial disease on MRI imaging of the spine. Given that younger age and earlier age of decompression is associated with improvement in curve angle, it seems important that MRI screening be considered in all patients regardless of neurological examination findings. There is a potentially long-term benefit in these patients. Multi-cross institutional prospective studies are encouraged to further investigate effect on curve angle.

Evaluation and management of adolescent idiopathic scoliosis: a review

Adolescent idiopathic scoliosis (AIS) is a 3D spinal deformity affecting children between the ages of 11 and 18, without an identifiable etiology. The authors here reviewed the available literature to provide spine surgeons with a summary and update on current management options.

Smaller thoracic and thoracolumbar curves can be managed conservatively with observation or bracing, but corrective surgery may be indicated for rapidly growing or larger curves. The authors summarize the atypical features to look for in patients who may warrant further investigation with MRI during diagnosis and review the fundamental principles of the surgical management of AIS.

Patients with AIS can be managed very well with a combination of conservative and surgical options. Outcomes for these children are excellent with sustained longer-term results.

A procedure to detect abnormal sensorimotor control in adolescents with idiopathic scoliosis

This work identifies, among adolescents with idiopathic scoliosis, those demonstrating impaired sensorimotor control through a classification procedure comparing the amplitude of their vestibular-evoked postural responses. The sensorimotor control of healthy adolescents (n=17) and adolescents with idiopathic scoliosis (n=52) with either mild (Cobb angle≥15° and ≤30°) or severe (Cobb angle >30°) spine deformation was assessed through galvanic vestibular stimulation. A classification procedure sorted out adolescents with idiopathic scoliosis whether the amplitude of their vestibular-evoked postural response was dissimilar or similar to controls. Compared to controls, galvanic vestibular stimulation evoked larger postural response in adolescents with idiopathic scoliosis. Nonetheless, the classification procedure revealed that only 42.5% of all patients showed impaired sensorimotor control. Consequently, identifying patients with sensorimotor control impairment would allow to apply personalized treatments, help clinicians to establish prognosis and hopefully improve the condition of patients with adolescent idiopathic scoliosis.

Intraspinal anomalies in early-onset idiopathic scoliosis

Aims

In the United Kingdom, lower incidences of intraspinal abnormalities in patients with early onset idiopathic scoliosis have been observed than in studies in other countries. We aimed to determine the rates of these abnormalities in United Kingdom patients diagnosed with idiopathic scoliosis before the age of 11 years.

Patients and Methods

This retrospective study of patients attending an urban scoliosis clinic identified 71 patients satisfying a criteria of: clinical diagnosis of idiopathic scoliosis; age of onset ten years and 11 months or less; MRI screening for intraspinal abnormalities. United Kingdom census data combined with patient referral data was used to calculate incidence.

Results

Mean age at diagnosis was six years with 39 right-sided and 32 left-sided curves. Four patients (5.6%) were found to have intraspinal abnormalities on MRI. These consisted of: two combined Arnold-Chiari type 1 malformations with syrinx; one syrinx with a low lying conus; and one isolated syrinx. Overall annual incidence of early onset idiopathic scoliosis was one out of 182 000 (0.0006%).

Conclusion

This study reports the lowest rates to date of intraspinal anomalies in patients with early onset idiopathic scoliosis, adding to knowledge regarding current incidences of these abnormalities as well as any geographical variation in the nature of the disease. Cite this article: Bone Joint J 2017;99-B:829–33.

MRI Screening in Operative Scheuermann Kyphosis: Is it Necessary?

STUDY DESIGN

Patients with preoperative spine magnetic resonance imaging (MRI) studies from a prospective multicenter study of operative adolescent Scheuermann kyphosis (SK).

OBJECTIVES

To investigate the usefulness of MRI screening in operative planning for SK surgeries.

SUMMARY OF BACKGROUND DATA

Neural axis abnormalities in operative SK have not been previously studied with MRI screening, despite its use.

METHODS

One orthopedic surgeon and two radiologists evaluated all images retrospectively. Radiographs were evaluated for kyphosis apex and magnitude. MRIs were evaluated for spinal cord abnormalities, epidural lipomatosis, location and number of vertebral wedging, Schmorl nodes and posterior disc herniations, frequency of spondylolysis, etc. The relationship of these pathologies to the kyphosis apex was explored. This group was compared to a surgical SK group without preoperative MRIs.

RESULTS

Eighty-six patients with MRIs, mean age 16.3 years, 64% male, and a mean preoperative kyphosis of 75.9° were evaluated. There were 17 spinal cord abnormalities. Low-lying conus was found in 2 patients, and syrinx in 15 (no Chiari malformations). Epidural lipomatosis was found in 49 patients, average of 5.7 levels. Anterior vertebral wedging occurred in all (mean 4.7 levels). Posterior disc herniations averaged 5.2 levels/patient and 1.8 levels caudad to the apex. Spondylolysis was reported in 8.1%. Four cases (4.7%) had the operative plan changed as a result of the preoperative MRI: two due to neural compression, one due to disc herniation and one due to a spinal cord draped over the apex. Thirty-one patients did not receive an MRI; there were no significant differences between the two groups. The rate of postoperative neurologic change was 3.5% in the MRI group and 3.2% in the no-MRI group.

CONCLUSIONS

Based on 4.7% of cases requiring a change in the operative plan as a result of preoperative MRI, the authors recommend considering performing screening MRI in operative SK patients.

Preoperative Magnetic Resonance Imaging Evaluation in Patients with Adolescent Idiopathic Scoliosis

Study Design

Retrospective case series.

Purpose

The purpose of this study was to examine the incidence of neural axis abnormalities and the relevant risk factors in patients with adolescent idiopathic scoliosis (AIS).

Overview of Literature

The use of preoperative magnetic resonance imaging (MRI) to assess the whole spine in patients with idiopathic scoliosis is controversial, and indications for such MRI evaluations have not been definitively established. However, we routinely use whole-spine MRI in patients with scoliosis who are scheduled to undergo surgical correction.

Methods

A total of 378 consecutive patients with presumed AIS who were admitted for spinal surgery were examined for neural axis abnormalities using MRI. To differentiate patients with normal and abnormal MRI findings, the following clinical parameters were evaluated: age, sex, menarcheal status, rotation angle (using a scoliometer), coronal balance, shoulder height difference, and low back pain. We radiographically evaluated curve type, thoracic or thoracolumbar curve direction, curve magnitude and flexibility, apical vertebral rotation, curve length, coronal balance, sagittal balance, shoulder height difference, thoracic kyphosis, and the Risser sign.

Results

Neural axis abnormalities were detected in 24 patients (6.3%). Abnormal MRI findings were significantly more common in males than in females and were associated with increased thoracic kyphosis. However, there were no significant differences in terms of the other measured parameters.

Conclusions

Among the patients with presumed AIS who received preoperative whole-spine MRI, 6.3% had neural axis abnormalities. Males and patients with increased thoracic kyphosis were at a higher risk.

The prevalence of intraspinal anomalies in infantile and juvenile patients with "presumed idiopathic" scoliosis: a MRI-based analysis of 504 patients

Background

Though several studies have reported the incidence of intraspinal neural axis abnormalities in infantile and juvenile “presumed idiopathic” scoliosis, there has been a varying prevalence ranging from 11.1 to 26.0 % based on a limited sample size. Therefore, such inconclusive findings have resulted in some questions on the MRI-associated role in the management of these patients. We aimed to investigate the prevalence and distribution of intraspinal anomalies in the infantile and juvenile patients with “presumed idiopathic” scoliosis and to explore the radiographic and clinical indicators with large sample size.

Methods

A total of 504 infantile and juvenile patients diagnosed with “presumed idiopathic” scoliosis were examined for potentially-existing neural axis abnormalities by MRI. Patients were grouped into two cohorts according to the presence of neural axis abnormalities. Radiographic parameters including curve magnitude, curve pattern, location of apex, degree of thoracic kyphosis, and span of curve were recorded and compared between the two groups. The prevalence of the neural abnormalities between the infantile-age group and juvenile-age group was also compared. The student t test was used to evaluate the differences of continuous variables and the chi-square test was used to evaluate the difference of categorical variables. Fisher exact test was applied to detect the difference of the rate of intraspinal anomalies between the “infantile idiopathic scoliosis” and “juvenile idiopathic scoliosis” group.

Results

Involving the spinal cord, 94 patients (18.7 %) were found to have a neural abnormality: Arnold-Chiari malformation alone in 43 patients, Arnold-Chiari malformation combined with syringomyelia in 18 patients, isolated syringomyelia in 13 patients, diastematomyelia in six patients, tethered cord combined with diastematomyelia in six patients, tethered cord alone in four patients, and other uncommon intraspinal abnormalities in the remaining four patients. Totally Arnold-Chiari malformation with or without syringomyelia accounted for 64.8 % (61/94) among all these abnormalities. Male gender, left thoracic curve and right lumbar curve were found to be significantly associated with the presence of neural axis abnormalities on MRI.

Conclusions

The incidence of neural axis abnormalities in the presumed IIS and JIS was 18.7 %. Thus a routine MRI evaluation appears warranted for those “presumed idiopathic” scoliosis patients if aged less than 10 years, being male or having left thoracic or right lumbar curve.

Candidate gene analysis and exome sequencing confirm LBX1 as a susceptibility gene for idiopathic scoliosis

BACKGROUND CONTEXT

Idiopathic scoliosis is a spinal deformity affecting approximately 3% of otherwise healthy children or adolescents. The etiology is still largely unknown but has an important genetic component. Genome-wide association studies have identified a number of common genetic variants that are significantly associated with idiopathic scoliosis in Asian and Caucasian populations, rs11190870 close to the LBX1 gene being the most replicated finding.

PURPOSE

The aim of the present study was to investigate the genetics of idiopathic scoliosis in a Scandinavian cohort by performing a candidate gene study of four variants previously shown to be associated with idiopathic scoliosis and exome sequencing of idiopathic scoliosis patients with a severe phenotype to identify possible novel scoliosis risk variants.

STUDY DESIGN

This was a case control study.

PATIENT SAMPLE

A total of 1,739 patients with idiopathic scoliosis and 1,812 controls were included.

OUTCOME MEASURE

The outcome measure was idiopathic scoliosis.

METHODS

The variants rs10510181, rs11190870, rs12946942, and rs6570507 were genotyped in 1,739 patients with idiopathic scoliosis and 1,812 controls. Exome sequencing was performed on pooled samples from 100 surgically treated idiopathic scoliosis patients. Novel or rare missense, nonsense, or splice site variants were selected for individual genotyping in the 1,739 cases and 1,812 controls. In addition, the 5'UTR, noncoding exon and promoter regions of LBX1, not covered by exome sequencing, were Sanger sequenced in the 100 pooled samples.

RESULTS

Of the four candidate genes, an intergenic variant, rs11190870, downstream of the LBX1 gene, showed a highly significant association to idiopathic scoliosis in 1,739 cases and 1,812 controls (p=7.0×10(-18)). We identified 20 novel variants by exome sequencing after filtration and an initial genotyping validation. However, we could not verify any association to idiopathic scoliosis in the large cohort of 1,739 cases and 1,812 controls. We did not find any variants in the 5'UTR, noncoding exon and promoter regions of LBX1.

CONCLUSIONS

Here, we confirm LBX1 as a susceptibility gene for idiopathic scoliosis in a Scandinavian population and report that we are unable to find evidence of other genes of similar or stronger effect.

The Role of Routine Preoperative Magnetic Resonance Imaging in Idiopathic Scoliosis: A Ten Years Review

Study Design

Prospective study.

Purpose

To determine the role of routine preoperative magnetic resonance imaging (MRI) to detect the incidence and risk factors for intraspinal anomalies in patients with idiopathic scoliosis.

Overview of Literature

The incidence and risk factors for intraspinal anomalies in patients with idiopathic scoliosis are controversial, and the indications for preoperative MRI in these patients vary among centers.

Methods

Information on patients with idiopathic scoliosis who were surgical candidates over 10 years (age at presentation, sex, magnitude and apex of major curve, intraspinal anomalies detected by MRI, and neurological examination results) were recorded, the patients were grouped according to the intraspinal anomaly, and the data were analyzed.

Results

Of the 271 patients with idiopathic scoliosis, 27 had neuroaxial abnormalities (9.9%). Of these 27 patients, 14 (52%) underwent a neurosurgical procedure. Significant differences were observed in the frequency of early disease onset and male sex (p<0.05) between the group of patients with neuroaxial abnormalities on preoperative MRI and those who did not have a cord anomaly. No difference was detected in the magnitude or direction of the curve.

Conclusions

Neuroaxial abnormalities in patients with idiopathic scoliosis and a normal neurological examination were highly frequent (9.9%). Missing these abnormalities before surgery could inflict catastrophic postoperative complications. The incidence of neuroaxial abnormalities was higher in male patients and in those with early onset disease. Thus, MRI is essential for all patients with idiopathic scoliosis who require medical intervention.

The association between Chiari malformation Type I, spinal syrinx, and scoliosis

OBJECT Chiari malformation Type I (CM-I) is often found in patients with scoliosis. Most previous reports of CM-I and scoliosis have focused on patients with CM-I and a spinal syrinx. The relationship between CM-I and scoliosis in the absence of a syrinx has never been defined clearly. The authors sought to determine if there is an independent association between CM-I and scoliosis when controlling for syrinx status. METHODS The medical records of 14,118 consecutive patients aged ≤ 18 years who underwent brain or cervical spine MRI at a single institution in an 11-year span were reviewed to identify patients with CM-I, scoliosis, and/or syrinx. The relationship between CM-I and scoliosis was analyzed by using multivariate regression analysis and controlling for age, sex, CM-I status, and syrinx status. RESULTS In this cohort, 509 patients had CM-I, 1740 patients had scoliosis, and 243 patients had a spinal syrinx. The presence of CM-I, the presence of syrinx, older age, and female sex were each significantly associated with scoliosis in the univariate analysis. In the multivariate regression analysis, older age (OR 1.02 [95% CI 1.01-1.03]; p < 0.0001), female sex (OR 1.71 [95% CI 1.54-1.90]; p < 0.0001), and syrinx (OR 9.08 [95% CI 6.82-12.10]; p < 0.0001) were each independently associated with scoliosis. CM-I was not independently associated with scoliosis when controlling for these other variables (OR 0.99 [95% CI 0.79-1.29]; p = 0.9). CONCLUSIONS A syrinx was independently associated with scoliosis in a large pediatric population undergoing MRI. CM-I was not independently associated with scoliosis when controlling for age, sex, and syrinx status. Because CM-I is not independently associated with scoliosis, scoliosis should not necessarily be considered a symptom of low cerebellar tonsil position in patients without a syrinx.

Spinal Cord Monitoring Data in Pediatric Spinal Deformity Patients With Spinal Cord Pathology

STUDY DESIGN

Retrospective.

OBJECTIVES

The purpose of this study is to review the efficacy of monitoring data and outcomes in pediatric patients with spinal cord pathology.

SUMMARY OF BACKGROUND DATA

The incidence of spinal cord pathology in pediatric patients with scoliosis has been reported between 3% and 20%. Previous studies demonstrated that intraoperative spinal cord monitoring (IOM) during scoliosis surgery can be reliable despite underlying pathology.

METHODS

A single-center retrospective review of 119 spinal surgery procedures in 82 patients with spinal cord pathology was performed. Diagnoses included Arnold-Chiari malformation, syringomyelia, myelomeningocele, spinal cord tumor, tethered cord, and diastematomyelia. Baseline neurologic function and history of prior neurosurgical intervention were identified. Outcome measures included ability to obtain reliable monitoring data during surgery and presence of postoperative neurologic deficits. Results were compared for 82 patients with adolescent idiopathic scoliosis (AIS).

RESULTS

Usable IOM data were obtained in 82% of cases (97/119). Twenty-two cases (18%) had no lower extremity data. Patients with Arnold-Chiari malformation or syringomyelia pathologies, in isolation or together, had a significantly higher rate of reliable data compared to other pathologies (p < .0001). Among study group cases with usable data, there were 1 false negative (1%) and 4 true positive (4%) outcomes. There were no permanent neurologic deficits. The spinal cord pathology group demonstrated 80% sensitivity and 92% specificity.

CONCLUSIONS

Spinal cord monitoring is a valuable tool in pediatric patients with spinal cord pathology undergoing spinal deformity surgeries. When obtained, data allow to detect changes in spinal cord function. Patients with a diagnosis of Arnold-Chiari or syringomyelia have monitoring data similar to those patients with AIS. Patients with other spinal cord pathologies have less reliable data, and surgeons should have a lower threshold for performing wake-up tests to assess spinal cord function intraoperatively.

Evaluation of coronal shift as an indicator of neuroaxial abnormalities in adolescent idiopathic scoliosis: a prospective study

Background

In previous studies, many indicator factors have been proposed to select patients who need an MRI screening of the spinal canal. In current study, the clinical and radiologic factors including coronal parameters of the curve were evaluated to find out which indicator is more important.

Methods

A prospective study included 143 consecutive patients with the diagnosis of adolescent idiopathic scoliosis who were treated between 2010 and 2013 at our spinal clinics. Only patients with normal or subtle neurologic findings were included. All patients were evaluated by a total spine MRI protocol for examination of neuroaxial abnormalities. Known indicators and also coronal shift were analysed in all patients with or without abnormal MRI.

Results

The incidence of neuroaxial abnormalities was 11.9% (17 of 143); only 5 patients (3.5%) were operated to treat their neuroaxial problem. The significant indicators of the abnormalities in our patients were: younger age at onset, asymmetric superficial abdominal reflex and, coronal shift more than 15 mm (P = 0.03). Some previously known indicators like atypical curves, male gender, double curves and absence of thoracic lordosis were not different between two groups of the patients.

Conclusions

A total spine MRI is recommended at presentation in patients with younger age, abnormal neurologic findings and severe coronal shift.

Surgical outcome of Chiari I malformation in children: clinico-radiological factors and technical aspects

PURPOSE

The optimal treatment for Chiari I malformation in children is still under debate. The aim of this study was to evaluate the surgical outcome of the pediatric Chiari I malformation,focusing on clinico-radiological factors and technical aspects.

METHODS

Fifty-six patients with Chiari I malformation who received surgery at Seoul National University Children’s Hospital were included. The mean age was 7.9 years. The patients were divided into three groups: group I (n =8) with hydrocephalus, group II (n =11) without syrinx, and group III (n =37) with syrinx. Group I received shunting operation initially,and others received foramen magnum decompression (FMD). Group III was further subdivided: group IIIa (n =9), minimal intradural manipulation, and group IIIb (n =27), active intradural manipulation. The outcomes were compared between the groups. The mean follow-up period was 75.9 months.

RESULTS

In group I, symptoms were resolved or had improved in most patients, with only one patient received additional FMD. Symptoms resolved or improved in 10 (91 %) and 25 cases (84 %) in groups II and III, respectively. Syrinx was markedly decreased in 31 cases (86 %) in group III. FMD was less effective for scoliosis (improved or stabilized in 57 %).The persistence of syrinx was related with an aggravation of scoliosis. The outcomes between group IIIa and IIIb showed no significant difference.

CONCLUSIONS

In most pediatric Chiari I patients with hydrocephalus,a shunting operation was sufficient. FMD showed high efficacy in treating patients without hydrocephalus. The extent of the intradural procedure did not have a significant effect on the clinical outcome.

Scoliosis-Associated Cervical Spine Pathologies

STUDY DESIGN

A total of 126 scoliosis patients admitted to the hospital were screened for concomitant cervical pathologies.

OBJECTIVES

To investigate the prevalence of cervical spine pathologies and the clinical relevance of magnetic resonance imaging (MRI) in the evaluation of patients with neuromuscular, congenital, syndromic, and idiopathic scoliosis.

BACKGROUND SUMMARY

With the development of MRI, upper neural axis abnormalities such as syringomyelia and Chiari malformation are increasingly being found in patients with scoliosis, but no report in the literature describes other pathologies in the cervical area seen concomitant with different scoliosis types.

METHODS

A total of 126 consecutive patients who were classified as having neuromuscular, congenital, syndromic, and idiopathic scoliosis were retrospectively evaluated. Data regarding cervical neural axis abnormalities obtained from the MRI studies were analyzed and classified into each type of scoliosis group.

RESULTS

A total of 126 patients with scoliosis were evaluated for hindbrain and cervical spine anomalies. Patients were divided into 4 groups regarding the type of scoliosis. The cervical spine of all patients was evaluated with MRI and other radiologic methods when needed. The most frequently seen pathology was syringomyelia. Other pathologies found included congenital vertebral anomalies, Chiari malformation, arachnoid cyst, atlanto-axial dissociation, split cord, posterior vertebral fusion, vertebral hypoplasia, neurenteric cyst, myelomalacia, dermoid cyst, and decrease in craniovertebral angle. Cervical pathologies were most frequently seen in neuromuscular scoliosis, followed by congenital and syndromic groups.

CONCLUSIONS

Cervical spinal pathologies vary according to the type of scoliosis. The number of cervical spinal pathologies diagnosed in idiopathic scoliosis patients was least compared with neuromuscular and syndromic groups. The most common pathology was syringomyelia, followed by congenital vertebral anomalies and cerebral tonsillar hernia. Preoperative MRI scan provides vital information regarding cervical spinal pathologies encountered in scoliosis patients.

Does curve convexity affect the surgical outcomes of thoracic adolescent idiopathic scoliosis?

BACKGROUND

Major left thoracic (LT) curve is an atypical type in adolescent idiopathic scoliosis (AIS) and showed independent clinical characteristics and natural history compared to major right thoracic (RT) curve. However, it's unclear whether the convexity of major thoracic curve would affect the surgical outcomes and risk of complications. A retrospective follow-up study was conducted to investigate whether the convexity of major thoracic curve would affect the surgical outcomes of patients with main thoracic AIS.

METHODS

Twelve LT-AIS patients underwent corrective spinal instrumentation and fusion were retrieved, and twelve patients with main RT-AIS matched for gender, chronological age, curve type, magnitude and surgical strategy were selected as control. All patients underwent at least 2-year follow-up. The pre- and post-operative radiographic parameters, intraoperative data and functional outcome assessed by Scoliosis Research Society questionnaire 22 (SRS-22) were analyzed and compared between two groups.

RESULTS

Patients with LT- and RT-AIS presented with similar magnitudes of thoracic curves, flexibility, fusion level and correction rate. Compared with RT-AIS, patients with LT-AIS showed longer operation time (average, 364 vs. 348 min) and larger amount intraoperative estimated blood loss (2,060 vs. 1,720 ml) although the differences were not statistically significant (p > 0.05). With at least 2-year follow-up, patients in two groups showed comparable loss of correction, coronal and sagittal balance, and the sagittal profiles. With regard to functional outcome, the scores of five categories of SRS-22 questionnaire were similar between two groups. No neurological or vascular complication was observed in these patients.

CONCLUSIONS

The radiographic and functional outcomes of LT-AIS patients underwent operation were comparable to those with RT-AIS. Longer operation time and more intraoperative blood loss may be expected in instrumentation and fusion for patients with LT-AIS, which might be because of the inconvenience on the surgical procedure.

[Scoliotic spine deformity in children and adolescents associated with the craniovertebral junction pathology]

This literature review is devoted to the clinical and pathogenic aspects of the relationship between Chiari type I malformation (CMT) and scoliosis. The view of the clinical presentation development in CMT associated with scoliosis is considered on the basis of both the CSF dynamics disturbances and vascular pathology of the craniovertebral junction. The role of the posterior atlanto-occipital membrane is evaluated. Case reports of the risk factors for scoliosis progression in patients with CMT are presented.

The risk factors of neurologic deficits of one-stage posterior vertebral column resection for patients with severe and rigid spinal deformities

PURPOSE

To determine the risk factors of neurologic deficits during PVCR correction, so as to help improve safety during and after surgery.

METHODS

A consecutive series of 76 patients with severe and rigid spinal deformities who were treated with PVCR at a single institution between October 2004 and July 2011 were included in our study. Of the 76 patients, 37 were male and 39 female, with an average age of 17.5 years (range 10-48 years). There were 52 adolescent patients (with an age <18 years) and 24 adult patients (with an age ≥18 years). Preoperatively, postoperatively and 6 months after surgery, we performed systemically neurologic function evaluations of each patients through meticulous physical examination. Any new abnormality or deterioration in evaluation of neurologic function than preoperative is reckoned postoperative neurologic deficits. Ten variables that might affect the safety of neurologic deficits during PVCR procedures, including imaging factors, clinical factors and operational factors, were analyzed using univariate analysis. Then the variables with statistical difference were analyzed by using multi-factor unconditional logistic regression analysis.

RESULTS

No patient in this series had permanent paraplegia and nerve root injury due to operation. Change of neurologic status was found in six patients after surgery. Results of single-factor comparison demonstrated that the following seven variables were statistically different (P < 0.05): location of apex at main curve (X 3), Cobb angle at the main curve at the coronal plane (X 4), scoliosis associated with thoracic hyperkyphosis (X 5), level of vertebral column resected (X 6), number of segmental vessels ligated (X 7), preexisting neurologic dysfunction (X 8), and associated with intraspinal and brain stem anomalies (X 9). The multi-factor unconditional logistic regression analysis revealed that X 8 (OR = 49.322), X 9 (OR = 18.423), X 5 (OR = 11.883), and X 6 (OR = 8.769) were independent and positively correlated with the neurologic deficit.

CONCLUSIONS

Preexisting neurologic dysfunction, associated with intraspinal and brain stem anomalies, scoliosis associated with thoracic hyperkyphosis and level of vertebral column resected are independent risk factors for neurologic deficits during PVCR procedure.

Are intraspinal anomalies in early onset idiopathic scoliosis as common as once thought? A two centre United Kingdom study

PURPOSE

Rates of neural axis abnormalities in infantile and juvenile idiopathic scoliosis may be as high as 50 %. We aimed to determine the rates of neural axis abnormalities in early onset idiopathic scoliosis patients in a British population.

METHODS

This retrospective study at two British spinal deformity clinics identified 72 patients satisfying the inclusion criteria of: (1) age at diagnosis of 7 years and younger, (2) idiopathic scoliosis and (3) magnetic resonance imaging of the neuraxis.

RESULTS

The mean age at diagnosis was 3.6 years and the mean Cobb angle was 47° with a near equal distribution of left (32) and right (36) sided curves. Eight (11.1 %) neural axis abnormalities consisting of two syrinxes, one Arnold-chiari Type I malformation and five combined (Arnold-chiari malformation Type I and syrinx) anomalies were identified.

CONCLUSIONS

This multi-centre study on the largest number of British subjects to date helps to establish the rates of neural axis abnormalities.

Indication for preoperative MRI of neural axis abnormalities in patients with presumed thoracolumbar/lumbar idiopathic scoliosis

PURPOSE

The purpose of this study was to investigate the incidence of neural axis abnormalities in patients with presumed "idiopathic" thoracolumbar or lumbar scoliosis by magnetic resonance imaging (MRI) and try to determine which clinical and radiographic characteristics correlate with neural axis abnormalities on MRI in these patients.

METHODS

The database of a single spinal deformity center was retrospectively reviewed to identify all patients with a primary diagnosis of idiopathic scoliosis (IS) between January 2003 and August 2011. A total of 446 patients with main thoracolumbar or lumbar curves were identified. Radiographic parameters including main curve Cobb angles, location of curve apex, span of main curve, thoracic kyphosis (T5-T12), thoracolumbar junction kyphosis (T10-L2), lumbar lordosis (L1-S1), and sagittal and coronal balance were measured.

RESULTS

Neural axis abnormalities were detected in 35 (7.8 %) patients. For patients with neural axis abnormalities, a higher proportion of male gender and long thoracolumbar curves were presented. In these patients, the mean age was smaller and the mean Cobb angle of main curve was larger. Greater thoracic kyphosis (≥ 30°) was more frequently found in those with neural axis abnormalities. The incidences of thoracolumbar junction hyperkyphosis were similar between two groups (P > 0.05). There was no difference between two groups as to lumbar lordosis and coronal and sagittal balance.

CONCLUSION

We recommend the routine use of MRI in the patients with one or more of the following characteristics: right curves, long curve span, apex at thoracolumbar spine and hyperthoracic kyphosis.

The use of routine preoperative magnetic resonance imaging in identifying intraspinal anomalies in patients with idiopathic scoliosis: a 10-year review

PURPOSE

This study sought to quantify the frequency of previously unidentified spinal cord anomalies identified by routine preoperative magnetic resonance imaging (MRI), in patients planned for surgical scoliosis correction.

METHODS

Our study group comprised 206 patients with idiopathic scoliosis who underwent deformity correction from 1998 to 2008. Clinical records of all the patients were retrospectively reviewed to ascertain the proportion having a neural abnormality on preoperative MRI scan.

RESULTS

Twenty of 206 patients (9.7 %) were diagnosed with an unexpected intraspinal anomaly on routine preoperative MRI. In all cases, a neurosurgical opinion was sought prior to further intervention. Of the 20 patients, 11 underwent a neurosurgical procedure (de-tethering of cord, decompression of Chiari, decompression of syrinx). There was no statistically significant difference between the group of patients who had intrinsic spinal cord anomalies on preoperative MRI and those did not have a cord abnormality with regard to age at presentation, gender, side of dominant curve and degree of curve (p < 0.05).

CONCLUSION

The high frequency of spinal cord abnormalities unidentified by preoperative neurological examination, and the frequent need for subsequent neurosurgical intervention, suggests that MRI assessment prior to deformity correction is important in the management of idiopathic scoliosis.

Tapering of the cervical spinal canal in patients with scoliosis with and without the Chiari I malformation

BACKGROUND

Cervical spinal canal tapering may increase CSF velocities and pressures. One report suggests that the cervical spinal canal tapers more steeply in patients with Chiari I than in healthy subjects. The goal of this study was to test the conclusion by measuring spinal canal tapering in another cohort of patients.

MATERIALS AND METHODS

Consecutive patients with scoliosis and MR imaging were selected. The MR images were evaluated for tonsillar herniation and syringomyelia. On a midline T2-weighted MR image, the anteroposterior diameter of the spinal canal was measured at each cervical level, and a linear trend line was fit by least-squares regression. The slope of this line was recorded as the taper ratio in millimeters/level. Patients with >5 mm of tonsillar herniation (with or without syrinx) were compared with those without tonsillar herniation (with or without syrinx). Differences in taper ratios for the 2 groups were tested for significance by the Kruskal-Willis test with significance set at .05.

RESULTS

Fifty-four patients with scoliosis were identified; 22 had a Chiari malformation and 32 did not. Syringomyelia was identified in 20 of the patients with Chiari and in 8 of the others. The taper ratios averaged -0.9 mm/level for the patients with a Chiari malformation (with or without a syrinx) and -0.4 mm/level for those without it, significant at P = .035. Syringomyelia did not substantially alter the taper ratio in either group.

CONCLUSIONS

Patients with scoliosis with a Chiari malformation have more steeply tapering cervical spinal canals than those without it.

Different curve pattern and other radiographical characteristics in male and female patients with adolescent idiopathic scoliosis

STUDY DESIGN

Retrospective radiographical study.

OBJECTIVE

To compare the sex differences in curve patterns and radiographical characteristics in patients who have adolescent idiopathic scoliosis (AIS).

SUMMARY OF BACKGROUND DATA

Sex differences in AIS have been documented in the incidence of curve progression, response to bracing, and outcomes of surgical treatment. However, limited information is available about the relation between sex and scoliosis curve patterns and radiographical presentations.

METHODS

A total of 359 male and 999 female patients with AIS with major curve of 20° or more were recruited. Standard posteroanterior and lateral radiographs of spine were reviewed to classify scoliosis curve patterns as typical or atypical and to measure curve severity and thoracic kyphosis. In 351 surgically treated patients, side-bending films were used to assess curve flexibility. Comparisons between male and female patients were made by subgrouping patients according to curve patterns and severity.

RESULTS

Atypical curves were more frequently observed in male (19.8%) than in female patients (8.9%) (P < 0.01). Sex differences were also found in the distribution of curve types. Main thoracic curve was the most common curve type in both sexes. Furthermore, significantly higher incidence of main thoracic curve in patients with severe AIS than in patients with moderate AIS was found in male (P < 0.001) but not in female patients. In patients with severe AIS who had typical curve patterns that included a major thoracic curve, male patients had larger magnitude of thoracic curve, more severe thoracic kyphosis, and more rigid thoracic and lumbar curves than female patients.

CONCLUSION

Atypical curve patterns were more predominant in male than in female patients with AIS. The thoracic curve in male patients with AIS might have higher incidence of progression than that in female patients. The higher rigidity of both thoracic and lumbar curves in male patients with AIS with severe curves might contribute to the lower curve correction rate and poor response to brace than in female cases.

Outcomes of Chiari I-associated scoliosis after intervention: a meta-analysis of the pediatric literature

PURPOSE

Various series have reported successful management of scoliosis after surgical treatment of the associated Chiari malformation, syrinx, or bracing. Multiple factors have been associated with curve progression, but interpretation of outcomes is confounded by the wide range of reported results and size of individual series. We attempted to evaluate the outcomes of Chiari I-associated scoliosis by performing a meta-analysis of currently published data.

METHODS

We conducted a systematic review of published articles using Medline, PubMed (from 1950 to January 2010), and reference lists of identified articles for Chiari malformation and scoliosis.

RESULTS

One hundred and twenty patients were identified in 12 studies, of them, 37 % were male. The mean age at the time of surgery was 9.7 ± 4.1 years. The mean curve magnitude at presentation was 34.4 ± 13.0° and progressed to a mean value of 38.9 ± 20.2°, with an average follow-up of 48.3 ± 48.2 months. After surgical intervention, curve magnitude improved in 37 % of patients (n = 42); there was no change in 18 % (n = 20), and curves progressed in 45 % (n = 51). Age (p = 0.0097) and presence of surgical intervention (foramen magnum decompression [p = 0.0099] and syrinx shunting/drainage [p = 0.0039]) were statistically associated with improvement of the scoliotic curve. Surgical decompression of the foramen magnum had the greatest impact on the scoliotic curves.

CONCLUSIONS

Data accrued from our analysis suggest that curve magnitude will improve after surgical treatment of the Chiari malformation in one third of patients, and curve progression will stabilize or improve in one half.

The correlation between coronal balance and neuroaxial abnormalities detected on MRI in adolescent idiopathic scoliosis

INTRODUCTION

The indications for magnetic resonance imaging in presumed adolescent idiopathic scoliosis (AIS) have not been established, with some studies suggesting that rates of spinal cord abnormalities are low and question the use of the routine MRI in AIS.

OBJECTIVE

Given the restraints on MRI resources the authors performed a retrospective audit to see if the presence of coronal or sagittal misbalance-balance could be used as a surrogate marker for the presence of spinal cord abnormalities in this patient group and hence reduce the need for unnecessary MRI scans.

METHODS

We performed a retrospective review of imaging of patients with AIS at our centre over a 2-year-period. All MRI scans were reported by the senior author and the presence of spinal cord abnormalities noted. All plain films were assessed by a senior SpR and ST2 orthopaedic surgeons for Cobb angle, coronal balance, sagittal balance and Lenke classification.

RESULTS

A total of 171 patients were identified with AIS. Of these, a total of 15 patients (9%) were found to have neural axis anomalies on MRI including syringomyelia, Chiari malformations and dural ectasia. The average Cobb angle was 44.9° with coronal balance varying from 67.2 mm left to 40.2 mm right. Sagittal balance varied from 125 mm negative to 83 mm positive. No correlation was found between coronal/sagittal misbalance and the presence of neural axis anomalies.

CONCLUSIONS

Our audit demonstrates that neither coronal nor sagittal misbalance should be used as an indicator of neural axis abnormalities.

Asynchronous neuro-osseous growth in adolescent idiopathic scoliosis--MRI-based research

Adolescent idiopathic scoliosis (AIS) is a common worldwide problem and has been treated for many decades; however, there still remain uncertain areas about this disorder. Its involvement and impact on different parts of the human body remain underestimated due to lack of technology in imaging for objective assessment in the past. The advances in imaging technique and image analysis technology have provided a novel approach for the understanding of the phenotypic presentation of neuro-osseous changes in AIS patients as compared with normal controls. This review is the summary of morphological assessment of the skeletal and nervous systems in girls with AIS based on MRI. Girls with AIS are found to have morphological differences in multiple areas including the vertebral column, spinal cord, skull and brain when compared with age- and sex-matched normal controls. Taken together, the abnormalities in the skeletal system and nervous system of AIS are likely to be inter-related and reflect a systemic process of asynchronous neuro-osseous growth. The current knowledge about the anatomical changes in AIS has important implications with respect to the understanding of fundamental pathomechanical processes involved in the evolution of the scoliotic deformity.