Clinical value of routine preoperative magnetic resonance imaging in adolescent idiopathic scoliosis. A prospective study of three hundred and twenty-seven patients

Does intervertebral disc degeneration in adolescent idiopathic scoliosis correlate with patient-reported pain scores? A review of 968 cases

PURPOSE

Report the rate and severity of degenerative disc disease (DDD) in non-surgical adolescent idiopathic scoliosis (AIS) patients and correlate these findings with patient-reported symptomatology scores. Additionally, to quantify the rate of concurrent pathological radiological findings in this group.

METHODS

This was a retrospective chart review study at a single tertiary centre. AIS patients aged 10-16 who had received a whole spine MRI between September 2007 and January 2019 and who had not received surgical intervention to their spine were included. MRI scan reports were screened to extract those who had evidence of DDD. These were then reviewed by a blinded second reviewer who graded every disc using the Pfirrmann grading system. SRS-22 scores were extracted for patients when available.

RESULTS

In total, 968 participants were included in the study. Of these, 93 (9.6%) had evidence of DDD, which was Pfirrmann grade ≥ 3 in 28 (2.9%). The most commonly affected level was L5/S1 (59.1% of DDD cases). A total of 55 patients (5.7%) had evidence of syringomyelia, 41 (3.4%) had evidence of spondylolisthesis (all L5/S1), 14 (1.4%) had bilateral L5 pars defects, and 5 (0.5%) had facet joint degeneration. Spondylolisthesis and bilateral pars defects were more common in patients with DDD identified on MRI scan (p < 0.001 and p = 0.04, respectively). Function (p = 0.048) and pain (p = 0.046) scores were worse in patients with DDD.

CONCLUSION

We present a baseline for the rate and severity of DDD in the non-operative AIS cohort. This should assist in decision-making and counselling of patients prior to surgery.

LEVEL OF EVIDENCE

III.

Utilization of pre-operative MRI to identify AIS patients at highest risk of intra-operative neuromonitoring alert

PURPOSE

Utility of pre-operative MRI for patients undergoing scoliosis correction has expanded to include an MRI classification for identifying patients at increased risk of experiencing intra-operative neuromonitoring (IONM) alerts based on the shape of the spinal cord and circumferential presence of CSF at the apex of the thoracic curve. In the present study, the authors explore the utility of this new MRI classification and multiple X-ray radiographic parameters in identifying the AIS sub-population at high risk of IONM alerts.

METHODS

AIS patients < 18 years old who underwent posterior spinal fusion between 2018 and 2022 at a single institution. Imaging reviewed to determine main thoracic (MT) and thoraco-lumbar (TL) Cobb angles, major thoracic Apical Vertebral Translation (AVT) and lumbar/thoraco-lumbar AVT (TL AVT), thoracic kyphosis (TK), coronal main thoracic Deformity Angular Ratio (cDAR), sagittal DAR (sDAR), and MRI to determine the spinal cord type (1, 2, or 3).

RESULTS

A total of 155 AIS patients who met the inclusion criteria between 2018 and 2022 were included. There was a trend to have an increased incidence of Type 3 spinal cord shape both with increase in the MT Cobb angle and MT AVT. There was also a shift toward more IONM alerts in patients with Type 3 (19.5%) spinal cords, AVT ≥ 5 cm (18.9%), and Cobb angle ≥ 650 (28.2%).

CONCLUSION

Higher magnitude of thoracic Cobb angle and AVT are associated with higher likelihood of type 3 spinal cord at the apex in MRI. Patients with Type 3 spinal cord, Cobb angle ≥ 650, AVT > 5 cm, and cDAR > 10 have higher likelihood to have IONM alerts. Patient with a Type 3 spinal cord and a Cobb angle ≥ 650 (50.0%), cDAR > 10 (43.7%), and AVT > 5 cm (35.2%) have the highest risk of having IONM alerts.

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.

A Survey of Methods and Technologies Used for Diagnosis of Scoliosis

The purpose of this article is to present diagnostic methods used in the diagnosis of scoliosis in the form of a brief review. This article aims to point out the advantages of select methods. This article focuses on general issues without elaborating on problems strictly related to physiotherapy and treatment methods, which may be the subject of further discussions. By outlining and categorizing each method, we summarize relevant publications that may not only help introduce other researchers to the field but also be a valuable source for studying existing methods, developing new ones or choosing evaluation strategies.

Melatonin and adolescent idiopathic scoliosis: The present evidence

INTRODUCTION

Adolescent idiopathic scoliosis (AIS) is a multifactorial condition with genetic predisposing factors, and several causes have been put forward for its aetiopathogenesis, including possible hormonal dysfunction. Melatonin seems to play significant role in AIS.

METHODS

A systematic search in different database, to July 2021, was performed to define the role of melatonin in the pathophysiology of adolescent idiopathic scoliosis. Eight suitable studies were identified.

RESULTS

The concentration and rhythm of melatonin secretion can play an important role by influencing the pathogenesis of adolescent idiopathic scoliosis.

CONCLUSIONS

Although there are many alterations of melatonin in subjects with adolescent idiopathic scoliosis, the many variables present do not allow to establish a direct cause-effect relationship.

LEVEL OF EVIDENCE

Level IV.

Scoliosis Management for Primary Care Practitioners

For many families, the possibility that their child may have scoliosis causes great anxiety because their child may be deformed for life, may need to wear a brace for years, or may need to undergo a large and dangerous operation. For most families, these fears are groundless. Up to 3% of the population has a spinal curvature, most of which are small curves that may not need referral or repeated imaging. Many adolescents with scoliosis do well and do not need to wear a brace or have surgery.

Increased cautiousness in adolescent idiopathic scoliosis patients concordant with syringomyelia fails to improve overall patient outcomes

Background:

Adolescent idiopathic scoliosis (AIS) is a common cause of spinal deformity in adolescents. AIS can be associated with certain intraspinal anomalies such as syringomyelia (SM). This study assessed the rate o f SM in AIS patients and compared trends in surgical approach and postoperative outcomes in AIS patients with and without SM.

Methods:

The database was queried using ICD-9 codes for AIS patients from 2003–2012 (737.1–3, 737.39, 737.8, 737.85, and 756.1) and SM (336.0). The patients were separated into two groups: AIS-SM and AIS-N. Groups were compared using t-tests and Chi-squared tests for categorical and discrete variables, respectively.

Results:

Totally 77,183 AIS patients were included in the study (15.2 years, 64% F): 821 (1.2%) – AIS-SM (13.7 years, 58% F) and 76,362 – AIS-N (15.2 years, 64% F). The incidence of SM increased from 2003–2012 (0.9 to 1.2%, P = 0.036). AIS-SM had higher comorbidity rates (79 vs. 56%, P < 0.001). Comorbidities were assessed between AIS-SM and AIS-N, demonstrating significantly more neurological and pulmonary in AIS-SM patients. 41.2% of the patients were operative, 48% of AIS-SM, compared to 41.6% AIS-N. AIS-SM had fewer surgeries with fusion (anterior or posterior) and interbody device placement. AIS-SM patients had lower invasiveness scores (2.72 vs. 3.02, P = 0.049) and less LOS (5.0 vs. 6.1 days, P = 0.001). AIS-SM patients underwent more routine discharges (92.7 vs. 90.9%). AIS-SM had more nervous system complications, including hemiplegia and paraplegia, brain compression, hydrocephalous and cerebrovascular complications, all P < 0.001. After controlling for respiratory, renal, cardiovascular, and musculoskeletal comorbidities, invasiveness score remained lower for AIS-SM patients (P < 0.001).

Conclusions:

These results indicate that patients concordant with AIS and SM may be treated more cautiously (lower invasiveness score and less fusions) than those without SM.

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.

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.

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.

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.

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.

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.

Prevalence and clinical relevance of underlying pathological conditions in painful adolescent idiopathic scoliosis: a MRI-based study

STUDY DESIGN

Cross-sectional comparative study.

OBJECTIVES

Evaluate prevalence and clinical relevance of an underlying pathology in painful adolescent idiopathic scoliosis (AIS) patients after a non-diagnostic history, physical examination and spinal X-ray using Magnetic Resonance Image (MRI) as diagnostic tool. Discrepancies regarding indications of routine MRI screening in painful AIS patients are multifactorial. Few studies have investigated relationship and practical importance of painful AIS with an underlying pathology by MRI.

METHOD

A total of 152-consecutive AIS patients complaining of back pain during a 36-month period were enrolled. All patients underwent whole-spine MRI after a non-diagnostic history, physical examination and spinal X-ray. Underlying pathologies were reported as neural and non-neural axis abnormalities based on MRI reports. Variables such as sex, age, constant or intermittent pain, night pain, back pain location (thoracic or lumbar pain), Cobb-angle and follow-up were evaluated as clinical markers to predict presence of underlying MRI pathologies.

RESULTS

The presence of an underlying pathology was found by MRI in 54 painful AIS patients (35.5%). Isolated syringomyelia was the only neural axis abnormality found in 6 patients (3.9%). Non-neural axis abnormalities (31.6%) were composed by: 32 herniated nucleus pulposus, 5 vertebral disc desiccation, 4 ovarian cysts, 3 renal cysts, 2 sacral cysts, and 2 vertebral hemangiomas. There was no association with gender, age of presentation, initial coronal Cobb angle and follow up; with presence of an underlying pathology. Lumbar pain location was identified as an adequate clinical marker that correlated with presence of an underlying pathology (p = 0.01).

CONCLUSIONS

Prevalence of underlying pathologies diagnosed by MRI in painful AIS was found high (35.5%), but it's clinical relevance and implication are debatable. The use of MRI did not affect orthopedic management of painful AIS patients who showed an underlying pathology. A thorough evaluation must be performed by clinicians; and discussed with patients and family prior to undergo further imaging management.

LEVEL OF EVIDENCE

Level III.

Scoliosis Progression After the Nuss Procedure for Pectus Excavatum: A Case Report

INTRODUCTION

Pectus excavatum and scoliosis are associated conditions with a high rate of coincidence. However, there are no reports to guide surgeons on the management of adolescents with moderate scoliosis and pectus excavatum, because there are conflicting conclusions in the literature regarding how the Nuss procedure with substernal bar affects scoliosis.

CASES

In 2017, we encountered two patients with moderate scoliosis treated with a spinal orthosis. After undergoing the Nuss procedure for pectus excavatum, their scoliosis acutely progressed into surgical magnitude requiring posterior instrumented spinal fusion. The first patient progressed 26° despite the pre-Nuss radiographs showing him to be Risser 4/5, while the second patient also progressed 26° from the Nuss procedure. Both patients acknowledged noncompliance with brace wear because of discomfort after the Nuss procedure. However, their progression rate still doubles the rate of reported rapid accelerators, indicating that a significant component of curve progression is directly attributed to forces on the spine from the corrective maneuver with substernal bar.

CONCLUSION

The purpose of this case report is to describe the features of these two patients to help with clinical decision-making in patients with moderate scoliosis (curves >25°) who are contemplating the Nuss procedure for correction of pectus excavatum. We caution patients and providers that spinal deformity could worsen with surgical intervention of the pectus excavatum via the Nuss procedure and necessitate scoliosis surgery.

Scoliosis in patients with Chiari malformation type I

The literature about the association between Chiari malformations (CMs) and scoliosis has been growing over the last three decades; yet, no consensus on the optimal management approach in this patient population has been reached. Spinal anomalies such as isolated syrinxes, isolated CM, and CM with a syrinx are relatively common among patients with presumed idiopathic scoliosis (IS), a rule that also applies to scoliosis among CM patients as well. In CM patients, scoliosis presents with atypical features such as early onset, left apical or kyphotic curvature, and neurological deficits. While spinal X-rays are essential to confirm the diagnosis of scoliosis among CM patients, a magnetic resonance imaging (MRI) is also recommended in IS patients with atypical presentations. Hypotheses attempting to explain the occurrence of scoliosis in CM patients include cerebellar tonsillar compression of the cervicomedullary junction and uneven expansion of a syrinx in the horizontal plane of the spinal cord. Early detection of scoliosis on routine spinal examination and close follow-up on curve stability and progression are essential initial steps in the management of scoliosis, especially in patients with CM, who may require full spine MRI to screen for associated neuro-axial anomalies; bracing and spinal fusion may be subsequently pursued in high-risk patients.

Evaluation of choroidal changes in adolescent idiopathic scoliosis using enhanced depth imaging optical coherence tomography

BACKGROUND

We aimed to evaluate the choroidal thickness (CT) in patients with adolescent idiopathic scoliosis (AIS) using enhanced depth imaging optical coherence tomography (EDI-OCT).

METHODS

In this cross-sectional, observational comparative study, 56 eyes of 56 patients with AIS and 56 eyes of 56 age- and sex-matched healthy subjects were included. All participants underwent complete ophthalmologic examination and CT measurements at the fovea and at 750 μm intervals from the fovea to 1,500 μm in the nasal and temporal site obtained by spectral domain EDI-OCT.

RESULTS

The mean subfoveal CT was lower in the AIS patients (285.2 ± 24.4 μm) than that of the controls (313.2 ± 28.8 μm; p < 0.001). The difference was also significant at all extrafoveal measurement points (p < 0.001 for all). There were negative correlations of CTs at subfoveal and extrafoveal locations with the Cobb's angle in the AIS patients (for subfoveal location: r = -0.71 and p < 0.001; and for extrafoveal locations: r = -0.66 and p < 0.001 at 750 μm in the nasal side; r = -0.64 and p < 0.001 at 1,500 μm in the nasal side; r = -0.71 and p < 0.001 at 750 μm in the temporal side; and r = -0.69 and p < 0.001 at 1,500 μm in the temporal side).

CONCLUSION

This preliminary study showed that AIS patients have thinner CT compared to that of healthy subjects. The lower CT was correlated with the increased angle of scoliosis.

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).

Intraspinal Anomalies in Individuals with Scheuermann's Kyphosis: Is the Routine Use of Magnetic Resonance Imaging Necessary for Preoperative Evaluation?

STUDY DESIGN

Retrospective study.

PURPOSE

This study aimed to determine the incidence of intraspinal pathologies (ISPs) in individuals with Scheuermann's kyphosis (SK) and to validate whether the routine use of magnetic resonance imaging (MRI) is necessary for preoperative evaluation.

OVERVIEW OF LITERATURE

There are several studies on the necessity of routine MRI screening and prevalence of ISPs related to different types of scoliosis have been conducted. However, despite the well-established association between ISPs and a higher risk for neurological complications there is no any study on the scientific literature concerning the prevalence of ISPs in patients with SK has been conducted.

METHODS

The database of the institution was retrospectively reviewed to identify all patients diagnosed with SK who underwent surgery between 2012 and 2015. Patients were excluded from the study if their hospital database records did not include spinal images, which are routinely collected before surgery. The presence or absence of ISPs, as indicated on magnetic resonance images, was evaluated by a radiologist.

RESULTS

Of the 138 potential participants, 120 were included in the study. Of these, seven patients (5.8%) had ISPs, and all the cases involved syringomyelia. None of the seven patients with ISPs required additional neurosurgical procedures before corrective surgery. No complications were reported during the perioperative period, and none of the patients developed postoperative neurological deficits.

CONCLUSIONS

According to this study, the incidence rate of ISPs in patients with SK was 5.8%, and we recommend that all patients with SK should be evaluated using MRI of the spine before corrective surgery.

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.

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.

Outcomes of patients with syringomyelia undergoing spine deformity surgery: do large syrinxes behave differently from small?

BACKGROUND CONTEXT

A paucity of data exists studying outcomes of patients with syringomyelia undergoing spinal deformity correction. The literature does not stratify patients by syrinx size, which is likely a major contributor to outcomes.

PURPOSE

The study aimed to compare differences in outcomes between patients with large (≥4 mm) and small syrinxes (<4 mm) undergoing spinal deformity correction.

DESIGN

This is a retrospective review.

PATIENT SAMPLE

The sample included 28 patients (11 with large syrinx [LS, >4 mm] and 17 with small syrinx [SS, <4 mm]).

OUTCOME MEASURES

The outcome measures were radiographic, operative, and neurophysiological measures.

METHODS

We retrospectively reviewed 28 patients with syringomyelia who underwent spine deformity surgery with 2-year follow-up. Demographic, surgical, and radiographic data were collected and compared preoperatively and at 2 years.

RESULTS

The LS group (11 patients) trended toward more left-sided thoracic curves (36% vs. 18%, p=.38) and was more likely to have had a Chiari decompression (45% vs. 12%, p=.08). The LS patients had larger preoperative major curves (LS=66° vs. SS=57°, p=.05), more thoracic kyphosis (LS=42°, SS=24°, p<.01), and greater rib prominences (LS=16°, SS=13°, p=.04). The LS patients had more levels fused (LS=12.2, SS=11.2, p=.05), higher estimated blood loss (EBL) (LS=1068 cc, SS=832 cc, p=.04), and a trend toward less percent correction of the major curve (LS=57%, SS=65%, p=.18). Four of 11 LS patients (36%) did not have somatosensory evoked potentials, and one of these also did not have motor evoked potentials. Neuromonitoring changes occurred in 3 of 11 (27%) LS patients and in none of the SS patients, with no postoperative deficits.

CONCLUSIONS

Outcomes of patients with syringomyelia undergoing spine deformity surgery are dependent on the size of the syrinx. Those with large syringomyelia are fused longer with more EBL and less correction. Spine surgeons should be aware that these patients are more likely to have less reliable neuromonitoring, with a higher chance of experiencing a change.

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.

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.

Spinal Deformity Associated with Chiari Malformation

Despite the frequency of Chiari-associated spinal deformities, this disease process remains poorly understood. Syringomyelia is often present; however, this is not necessary and scoliosis has been described in the absence of a syrinx. Decompression of the hindbrain is often recommended. In young patients (<10 years old) and/or those with small coronal Cobb measurements (<40°), decompression of the hindbrain may lead to resolution of the spinal deformity. Spinal fusion is reserved for those curves that progress to deformities greater than 50°. Further research is needed to understand the underlying pathophysiology to improve prognostication and treatment of this patient population.

Intrathecal Anomalies in Presumed Infantile Idiopathic Scoliosis: When Is MRI Necessary?

STUDY DESIGN

Retrospective review.

OBJECTIVE

To determine the rate of abnormal magnetic resonance imaging (MRI) findings in patients with presumed infantile idiopathic scoliosis (IIS) and the rate of neurosurgical intervention in those patients, and to develop a guideline concerning when to obtain an MRI.

SUMMARY OF BACKGROUND DATA

The reported rate of intrathecal anomalies associated with presumed IIS varies in the literature (12% to 50%). Conclusions have led to conflicting recommendations concerning when an MRI is indicated.

METHODS

After appropriate internal review board approval, the authors retrospectively reviewed the medical records of patients from a single institution meeting the inclusion criteria: presumed idiopathic curve with a magnitude of ≥20°, age <36 months at diagnosis, normal neurologic examination, and presentation between 2002 and 2010. The authors reviewed the MRI findings, whether neurosurgical intervention took place, and the orthopedic treatment course (observation, brace, cast, or surgery).

RESULTS

A total of 56 patients were identified and reviewed; 43 had had an MRI. Seven of 43 patients were found to have an anomaly (16.2%). A fatty filum was identified in 2 patients, a syrinx in 3, Chiari I malformation in 2, and a tethered cord in 1 (this patient also had a syrinx). Two of the 7 patients required neurosurgical intervention (28%). Patients who did not have an MRI were statistically younger, had smaller Cobb angles, and required less orthopedic treatment.

CONCLUSIONS

The incidence of intrathecal anomalies (16.2%) at the authors' institution was similar to previously published reports; however, the need for neurosurgical intervention was significantly lower in this study (28%). For younger patients with small curves (<30°) who do not require orthopedic treatment, MRI under sedation can be delayed or avoided. Clinical judgment should be the determinant for whether to use MRI when evaluating patients with presumed IIS.

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.

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.

Pathogenesis and biomechanics of adolescent idiopathic scoliosis (AIS)

Adolescent idiopathic scoliosis is defined as a scoliosis that starts after the age of ten and has no clear underlying disease as a reason for its development. There is, however, a disparity between the growth of the vertebral bodies anteriorly and that of the posterior elements. The vertebral bodies grow faster than the posterior elements, resulting primarily in a lordosis. The diminished dorsal growth impedes the ventrally located vertebral bodies from increasing in height, forcing them to become distorted, i.e., rotate, in order to create space for themselves. This produces a rotational lordosis. The idea of looking at it in this way dates back to Somerville in 1952. Many recent studies have confirmed this idea and have shown that the spinal canal is shorter than the anterior ligament of the vertebral bodies. In a mathematical model of the spine it was demonstrated that-although the vertebral column in humans is still predominantly loaded in an axial direction-certain segments of the human spine (especially the backward inclined segments) are subject to dorsally directed shear loads as well. In addition to the antero-posterior difference in growth, there is also a deformation of the vertebral bodies itself in 3-D. This is probably secondary and not primary effects, but this question is still under discussion. For the treatment of scoliosis, the biomechanical principles of axial and transverse forces are used. The combination of axial and transverse loads is most beneficial for all curves. The axial forces provide most of the corrective bending moment when deformity is severe, while the transverse loads take over the correcting function when deformity is mild. The deformity angle of 53° is the break-even point for the axial and transverse loads. In more severe curves transverse forces become less and less efficient, while axial forces rapidly gain more and more effect.

Clinical investigation and imaging

Adolescent idiopathic scoliosis (AIS) affects 2-4 % of children and is diagnosed between age 10 and skeletal maturity. The female to male ratio for mild curves less than 20° is 1.5:1; however, progression to a severe deformity occurs more often in females (Weinstein in JAMA 289(5):559-567, 2003). Despite significant ongoing research, including into the genetic basis for AIS, there are currently no identifiable causes, and therefore the disorder still remains a diagnosis of exclusion. History, physical examination and radiographic assessment must exclude other possible causes of spinal deformity and are crucial in predicting the risk of curve progression. History should focus on family history, menarche, presence or absence of pain, sports activities and neurologic changes. Physical examination concentrates on anthropometric data, pubertal staging, neurologic testing and specific investigation of the spine, with the Adams' forward bending test being the most meaningful step to evaluate trunk rotation. Definitive diagnosis cannot be made without imaging. The gold standard remains plain radiography with assessment of the Cobb angle on a standing coronal radiograph of the entire spine. A lateral X-ray is used for assessing sagittal balance and for evaluating the deformity in the sagittal plane. If available, surface topography can accompany the follow-up in AIS, reducing the radiation exposure. The role of magnetic resonance imaging (MRI) in AIS is an ongoing matter of debate. Common indications for MRI are the presence of an atypical curve pattern and abnormal neurological findings.

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.

Adolescent scoliosis classification and treatment

Adolescent idiopathic scoliosis (AIS) affects up to 3% of the population. It can be stratified by curve type according to the Lenke classification. This classification system incorporates curve magnitude, flexibility, the lumbar modifier, and the sagittal plane. The Lenke classification serves as a guide for selection of levels for surgical treatment of AIS. Surgical treatment of AIS includes anterior and posterior approaches; most AIS is treated through a posterior approach. Surgical goals include maximizing correction in the coronal, sagittal, and axial planes.

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.

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.

Magnetic resonance imaging evaluation of patients with idiopathic scoliosis: a prospective study of four hundred seventy-two outpatients

STUDY DESIGN

A prospective study of magnetic resonance imaging findings in outpatients with idiopathic scoliosis.

OBJECTIVE

The purpose of this study was to determine the prevalence of neural axis abnormalities in outpatients with scoliosis and to analyze the characteristics of patients who had such abnormalities.

SUMMARY OF BACKGROUND DATA

In previous studies, neural axis abnormalities were found in 2.9% to 37% of patients with idiopathic scoliosis. The current guidelines for MRI screening in scoliosis are valuable, and the proposed indications for performing MRI in the literature include early onset, atypical curvature, double thoracic curve (King type-5), rapid progression, male gender, and abnormal neurologic findings.

METHODS

A total of 472 outpatients with a primary diagnosis of idiopathic scoliosis were examined for neural axis abnormalities by magnetic resonance imaging. Logistic regression was used to determine significant predictors of neural axis abnormalities on MRI.

RESULTS

The incidence of neural axis abnormalities on MRI was 3.8% (18 of 472 patients). Among the 18 patients, 6 had a Chiari I malformation alone, 10 had a Chiari I malformation combined with syringomyelia, and 2 had a syringomyelia without Chiari I malformation. Male gender, patients younger than 11 years old, and abnormal superficial abdominal reflexes were significantly associated with the detection of neural axis abnormalities on MRI.

CONCLUSION

We recommend routine use of MRI in male patients, younger than 11 years old, and abnormal superficial abdominal reflexes. Even if a patient has no specific indications for MRI, we recommend its routine use in preoperative planning.

Scoliosis and Chiari malformation Type I in children

OBJECT

The identification of Chiari malformations Type I (CM-Is) has increased in recent years, commonly during MR imaging for evaluation of a possible cause of scoliosis. The treatment of this abnormality remains controversial, and the expected success of treatment is unclear. The goal of the present study is to evaluate the effects of a craniotomy for CM-I decompression on scoliosis in children and adolescents.

METHODS

The authors conducted a 10-year retrospective review of pediatric patients who were found to have a CM-I during evaluation for scoliosis. Seventy-nine patients were identified, ranging in age from 6 months to 18 years (median 12 years). There were 42 girls (54%) and 37 boys (46%). All were noted on MR imaging to have hydrosyringomyelia of the spinal cord. Forty-nine patients had curvatures less than 20° prior to treatment. The other 30 patients had curves ranging from 25° to 80° and underwent orthopedic follow-up and treatment. None of these patients were referred for specific neurological complaints, but 12 (16%) had neurological signs on physical examination. All were treated with a craniocervical decompression in a standard fashion. Follow-up ranged from 6 to 93 months with a median of 35 months. Magnetic resonance images obtained at 6 months postoperatively and serial standing anteroposterior spine radiographs were used to evaluate outcomes.

RESULTS

On the MR images obtained 6 months postoperatively, 70 patients (89%) had a significant reduction in the syrinx with an associated ascent of the cerebellar tonsils. Persistent large syringes were treated with reoperation in 6 patients, and shunts were inserted for hydrocephalus in 2 patients. None of the 49 patients with curves less than 20° had progression of their curvature postoperatively. Of the 30 patients with curves greater than 25°, 9 had no change in the scoliosis or had a reduction in curve magnitude after Chiari decompression. This group required no further therapy and was effectively treated by Chiari decompression alone. Twenty-one patients required further scoliosis treatment after Chiari decompression; 12 required orthotic treatment, 11 received spinal instrumentation and fusion surgery, and 2 received orthoses followed by fusion and instrumentation. The severity of the curvature beyond 20° did not predict the need for spinal surgery.

CONCLUSIONS

This large series reports on the efficacy of treatment for scoliosis associated with a CM-I and syrinx in children. A CM-I decompression alone was adequate treatment for mild scoliosis of less than 20°. Patients with scoliosis greater than 20° required bracing and/or spinal fusion surgery 70% of the time in addition to the CM-I decompression.