Spinal cord and brain stem anomalies in scoliosis: MR screening of 26 cases

The spinal cord and brain were examined with magnetic resonance (MR) in 26 patients with idiopathic scoliosis to study the prevalence of spinal cord and brainstem anomalies. Two patients had small centrally located spinal cord syrinxes, one at C6-C8 and the other at T6-T8, without association with any brainstem or cerebellar deformity. the lowest position of the cerebellar tonsils was 0.5 cm below the foramen magnum, which was also seen in 2 other patients. Scoliosis associated with syringomyelia may be more common than previously thought, and may be wrongly classified as idiopathic. A neurogenic cause of scoliosis should always be considered, and at least in atypical cases be excluded by MR imaging of the spinal cord. MR should be mandatory before bracing or operative correction of scoliosis.     

Spinal cord and brain stem anomalies in scoliosis. MR screening of 26 cases

The spinal cord and brain were examined with magnetic resonance (MR) in 26 patients with idiopathic scoliosis to study the prevalence of spinal cord and brainstem anomalies. Two patients had small centrally located spinal cord syrinxes, one at C6-C8 and the other at T6-T8, without association with any brainstem or cerebellar deformity. The lowest position of the cerebellar tonsils was 0.5 cm below the foramen magnum, which was also seen in 2 other patients. Scoliosis associated with syringomyelia may be more common than previously thought, and may be wrongly classified as idiopathic. A neurogenic cause of scoliosis should always be considered, and at least in atypical cases be excluded by MR imaging of the spinal cord. MR should be mandatory before bracing or operative correction of scoliosis.     

Scoliosis as the first sign of a cystic spinal cord lesion

Summary We reviewed the cases of ten patients with scoliosis as the first sign of a cystic spinal cord lesion with the aim of identifying and studying early patient and curve characteristics. All patients were examined with magnetic resonance (MR) imaging of the brain and spinal cord and quantitative thermal testing (QTT). The mean Cobb angle was 22° and the curves were right thoracic in seven patients, left thoracic in two, and left lumbar in one, when first seen for scoliosis. In six patients the cystic lesion was found in routine screening for syringomyelia, which is performed in all cases of congenital and juvenile scoliosis and in adolescent scoliosis before bracing. In four patients, it took up to 17 years following the initial diagnosis of scoliosis before neurologic deterioration warranted MR imaging, disclosing two Chiari I associated syrinxes and two cystic spinal cord tumors. QTT revealed a subelinically decreased sensation in two of the patients with no findings other than scoliosis. It also verified the decreased sensation in all patients in whom neurologic deterioration had complicated the clinical course of their scoliosis. More frequent spinal MR screening of patients with supposed juvenile or adolescent idiopathic scoliosis is indicated, regardless of curve type, to exclude a neurogenic cause. QTT documents subclinical as well as overt decreased sensation, and is valuable in the serial follow-up of these patients to monitor the progress or the response to treatment of the cystic lesion.Presented in part at the meeting of the European Spinal Deformities Society, Lyon, France, 17–19 June 1992     

Occult spinal cord abnormalities in children referred for orthopedic complaints

This study reviews spinal cord abnormalities found in children initially referred for an orthopedic problem. Over a 5-year period in an academic pediatric orthopedic referral clinic, 167 children aged 3 months to 18 years (average, 9.4 years) underwent spine magnetic resonance imaging (MRI) scans and had records available for review. The patients were divided into 7 major groups based on the primary indication for the MRI. The frequency of spinal cord pathology was as follows: 3 of 35 patients with atypical idiopathic scoliosis, 1 of 19 with neuromuscular scoliosis, 6 of 18 with congenital scoliosis, 1 of 50 with unexplained back pain, 3 of 17 with gait abnormality, 5 of 14 with limb pain or weakness, and 4 of 8 with rigid or recurrent foot deformity. Spine MRI was not very helpful in evaluating children who had some degree of back pain without neurological signs or symptoms. However, the spine MRI was helpful in evaluating children with atypical idiopathic scoliosis or congenital scoliosis, gait abnormality, limb pain or weakness, or rigid or recurrent foot deformities. Given the high frequency of occult spinal cord abnormality in children with severe foot deformity, the use of screening spine MRI may be especially useful in this group.     

"特发性"胸椎左侧凸患者并发脊髓病变及其临床意义

目的 探讨对临床上无明显神经损害的"特发性"胸椎左侧凸患者存在的脊髓病变情况,并分析其临床意义.方法 1997年10月至2003年10月共诊治"特发性"胸椎左侧凸59例,其中男性31例,女性28例;年龄7～44岁,平均15岁;Cobb角15°～108°,平均56°.所有病例经临床及影像学检查,排除神经纤维瘤及先天性脊椎发育异常等病因.对临床诊断为"特发性"胸椎左侧凸的患者行全脊髓磁共振成像(MRI)检查,对脊髓病变的发生率进行统计.结果 59例"特发性"胸椎左侧凸患者经全脊髓MRI检查后,共有33例发现髓内病变,髓内病变发生率为56%,其中Chiari畸形合并脊髓空洞24例,脊髓空洞5例,Chiari畸形、脊髓空洞、脊髓裂1例,Chiari畸形、脊髓空洞、脊髓栓系1例,脊髓空洞合并栓系1例,Dandy-Walker畸形1例.其余26例未发现脊髓病变.分析伴有脊髓病变的胸椎左侧凸患者中男性比例及平均Cobb角均显著大于无脊髓病变的胸椎左侧凸(P＜0.05).结论 对于胸椎左侧凸,尤其是男性、Cobb角较大的患者需高度怀疑伴有脊髓病变.对于此类患者术前常规全脊髓MRI检查具有重要意义.     

Childhood scoliosis revealing spinal cord tumors

Spinal cord tumors typically show slow and insidious growth and scoliosis may be the only presenting feature of these lesions. The aim of this study is to determine the clinical and/or imaging signs that can contribute in uncovering the underlying etiology of a presumed “idiopathic” scoliosis. We retrospectively reviewed seven cases of histologically confirmed spinal cord tumors presenting as scoliosis and diagnosed with MRI in our institution between 1996 and 2003. The children (six males and one female) were aged from 3 to 10 years. The scoliosis was associated with spinal pain and/or stiffness in all cases. Accurate neurological evaluation showed a motor deficit and/or mild neurological signs in all cases. Plain radiographs showed widening of the spinal canal in three patients. MRI allowed the diagnosis of spinal cord tumor in all patients. Associated syrinx was noted in five cases. Of which one child was presented with a “torticolis”, one with a localized thoraco–lumbar hyperkyphosis, three with left-sided thoracic curve and two with right-sided thoracic curve. All patients underwent surgical resection. Histological study concluded to astrocytomas (n=4), ependymoma (n=2) and epidermoïd cyst (n=1). Scoliosis should be considered as idiopathic only occult causes have been excluded. Neurological evaluation of these patients must be accurate. Early age of onset, male gender spinal pain and/or stiffness, left-sided curve, neurological signs, radiographic widening of the spinal canal are considered as atypical features and must lead to further investigation by MRI.     

特发性左侧胸椎侧凸

目的：探讨特发性左侧胸椎侧凸的临床特点及其可能病因。方法：对77例特发性左侧胸椎侧凸作回顾性分析,其中23例行肌电图检查。47例行全脊柱MRI检查。结果：物理检查12例有异常神经学发现,肌电图检查23例均提示神经原性损害,MRI检查有9例证实神经异常。结论：特发性左侧腰椎侧凸与脊髓异常有关,对于此类畸形应常规行MRI检查,以免遗漏脊髓异常。     

Efficacy of intraoperative monitoring for pediatric patients with spinal cord pathology undergoing spinal deformity surgery.

STUDY DESIGN: A retrospective study of 38 pediatric patients with spinal cord pathology who underwent corrective spinal deformity surgery from January 1989 through June 1998. OBJECTIVES: To report reliability and specificity in obtaining intraoperative data in this population. These data were compared with monitoring results obtained in a group of pediatric patients with idiopathic scoliosis. SUMMARY OF BACKGROUND DATA: Reports in the literature suggest intraoperative monitoring for patients with spinal cord pathology may be of limited value. No optimal monitoring protocol has been suggested for this population. METHODS: The study group consisted of 38 pediatric patients with a diagnosis of spinal cord pathology who underwent corrective spinal deformity surgery from January 1989 through June 1998. All patients had lower extremity function. Somatosensory and neurogenic motor evoked potentials were used to monitor neurologic status during surgery. These data were compared with data obtained in 429 pediatric patients with idiopathic scoliosis. Study patients were divided into Group I, those who had had spinal cord surgery (n = 20), and Group II, those who had not (n = 18). RESULTS: Somatosensory evoked potentials were obtained in 93.2% and remained consistent with baselines in 87.2% of the study group patients. Neurogenic motor evoked potentials were obtained in 50.8% of the study subjects and remained consistent in 76.6% of those cases. The false-positive rate was 27.1% in the study group, compared with 1.4% in the group with idiopathic scoliosis. The study group had no true-positive or false-negative findings. Group I data differed from Group II data. CONCLUSIONS: Intraoperative monitoring should be used in patients with spinal cord pathology who undergo surgery for spinal deformity. Monitoring should not miss a neurologic deficit but demonstrates greater variability, resulting in more frequent use of an intraoperative wake-up test.     

Segmental vessel ligation in patients undergoing surgery for anterior spinal deformity

Segmental vessel ligation during anterior spinal surgery has been associated with paraplegia. However, the incidence and risk factors for this devastating complication are debated. We reviewed 346 consecutive paediatric and adolescent patients ranging in age from three to 18 years who underwent surgery for anterior spinal deformity through a thoracic or thoracoabdominal approach, during which 2651 segmental vessels were ligated. There were 173 patients with idiopathic scoliosis, 80 with congenital scoliosis or kyphosis, 43 with neuromuscular and 31 with syndromic scoliosis, 12 with a scoliosis associated with intraspinal abnormalities, and seven with a kyphosis. There was only one neurological complication, which occurred in a patient with a 127 degrees congenital thoracic scoliosis due to a unilateral unsegmented bar with contralateral hemivertebrae at the same level associated with a thoracic diastematomyelia and tethered cord. This patient was operated upon early in the series, when intra-operative spinal cord monitoring was not available. Intra-operative spinal cord monitoring with the use of somatosensory evoked potentials alone or with motor evoked potentials was performed in 331 patients. This showed no evidence of signal change after ligation of the segmental vessels. In our experience, unilateral segmental vessel ligation carries no risk of neurological damage to the spinal cord unless performed in patients with complex congenital spinal deformities occurring primarily in the thoracic spine and associated with intraspinal anomalies at the same level, where the vascular supply to the cord may be abnormal.     

The role of routine magnetic resonance imaging in the preoperative evaluation of adolescent idiopathic scoliosis

The routine use of magnetic resonance imaging (MRI) in adolescent idiopathic scoliosis remains controversial, and current indications for MRI in idiopathic scoliosis vary from study to study. The purpose of this study was to demonstrate the prevalence of neural axis malformations and the clinical relevance of routine MRI studies in the evaluation of patients with adolescent idiopathic scoliosis undergoing surgical intervention without any neurological findings. A total of 249 patients with a diagnosis of idiopathic scoliosis were treated surgically between the years 2002 and 2007. A routine whole spine MRI analysis was performed in all patients. On the preoperative clinical examination, all patients were neurologically intact. There were 20 (8%) patients (3 males and 17 females) who had neural axis abnormalities on MRI. Three of those 20 patients needed additional neurosurgical procedures before corrective surgery; the remaining underwent corrective spinal surgery without any neurosurgical operations. Magnetic resonance imaging may be beneficial for patients with presumed idiopathic scoliosis even in the absence of neurological findings and it is ideally performed from the level of the brainstem to the sacrum.     

Preoperative radiological and electrophysiological evaluation in 100 adolescent idiopathic scoliosis patients

This is a prospective study of spinal magnetic resonance imaging (MRI), electrophysiological recordings, and neurological examinations of 100 patients admitted for surgery for adolescent idiopathic scoliosis (AIS), which was conducted to assess the prevalence of structural and functional abnormalities within the spinal cord in patients with clinically normal neurologic condition. In all patients the clinical diagnosis and intact neurological condition was ascertained by a spinal orthopedic surgeon. Full-length spinal axis MRI studies (T1/T2 sequences) and somato-sensory evoked potentials of the tibial nerves (tSSEPs) were preoperatively assessed by independent evaluators blinded to the patients' medical histories. Structural spinal cord abnormalities were found in three of 100 AIS patients on MR imaging. In one patient a Chiari malformation type 1 with an accompanying syringomyelia was diagnosed, which required a suboccipital decompression. In the other two patients small thoracic syringomyelias were diagnosed. Abnormalities of spinal cord function were detected in 68% of the 100 patients: tSSEP latencies corrected for body height were increased in 56% of the patients; pathological differences between tSSEPs on the left and right sides were present in 17% (12% in combination with a prolongation of the latency). The findings of this study indicate that MRI and electrophysiological examinations are essential to assess spinal cord abnormalities that are clinically not detectable in AIS patients. Even in patients with intact neurologic condition and clinically typical right-curved thoracic scoliosis, the possibility of intraspinal pathologies should be ruled out by MRI. It is especially important to detect structural pathologies like syringomyelia and Chiari malformation before proceeding with scoliosis surgery, as these conditions are associated with a higher neurological risk during scoliosis surgery. The electrophysiological recordings made in the present study, with the high number of pathological tSSEPs, are indicative of functional abnormalities with a subclinical involvement of the recorded neuronal pathways. The relevance of the latter findings is not yet clear, but pre-operative tSSEP examinations offer the possibility of assessing alterations in spinal cord function that are undetectable by clinical examination.     

青少年特发性脊柱侧凸的全脊柱三维MRI特点及与侧凸严重度相关性研究

目的 研究青少年特发性脊柱侧凸(adolescent idiopathic seoliosis,AIS)的MRI特征性变化,探讨AIS的MRI特征性变化与侧凸严重度的相关性.方法 应用三维莺建MRI技术对90例青少年(49例AIS,41名健康青少年)进行全脊髓脊柱和后脑MR检查.测量颈椎和胸椎各节段的脊髓最大前后径(AP)、最大横向直径(TS)和凸凹侧脊髓旁间隙(LCS)、小脑扁桃体与枕骨大孔基线的距离、齿突与枕骨大孔基线的距离、颈髓中轴线与延髓中轴线夹角(α)、枕骨大孔基线与延髓中轴线夹角(β)、脊髓面积、椎管面积、脊髓椎管面积比,测量脊髓全长、脊柱全长、脊髓脊柱全长比.结果 与健康对照组相比,AIS患者的AP、TS、AP/TS 和LCS比值明显增加,小脑扁桃体位置相对枕骨大孔明显下移,脊髓圆锥位置相对上移,β角减小,脊髓椎管面积比增大(P＜0.01);AIS组与对照组相比,全脊髓或全脊柱长度差异无统计学意义,但脊髓脊柱全长比明显减小(P＜0.01),与Cobb角无明显相关性.AP、AP/TS和LCS比值与Cobb角明显正相关(P＜0.05).结论 AIS患者在脊髓和脊柱的横断面上存在显著性形态学异常,部分与Cobb角有明显正相关;脊髓和脊柱纵轴上存在明显的脊髓牵拉受限,提示可能存在神经系统和骨骼系统的生长不平衡,这些可能与AIS的发病机制有关.     

MRI三点定位扫描技术在脊柱侧凸术前评估中的意义

目的：探讨MRI三点定位（MR 3PPS）扫描技术在脊柱侧凸患者术前评估中的应用价值。方法：对261例普涵X线平片显示脊柱侧凸的患者应用MR 3PPS扫描技术，以自旋回波T1WI及T2WI序列在同一幅同像上显示整个脊柱及椎管内脊髓全貌。结果：261例均可在一幅同像上完整最示扭曲的脊柱及椎管内脊髓的全貌，了解脊柱侧凸的程度、伴发畸形、椎管内脊髓情况及椎体骨质异常等表现。结论：MR3PPS技术的应用大大提高了诊断脊柱侧凸及了解是否伴发其它畸形的直观性和准确性，是术前正确评估脊柱侧凸、伴发畸形和了解椎管内情况的重要手段，对脊柱侧凸患者手术治疗有很好的指导作用。     

A myelographic study of idiopathic scoliosis--with special reference to its clinical significance

The purpose of this study was to investigate the concealed anomaly of the spinal cord in the so-called idiopathic scoliosis. Thirty-three patients with idiopathic scoliotic curvatures underwent metrizamide myelography before surgery from 1979 through 1985. Spinal cord anomalies were found in 8 of the 33 patients (abnormal group). They were 3 patients with Arnold-Chiari malformation with syringomyelia, 3 with syringomyelia and 2 with "narrowed dural tube". The remaining 25 patients (normal group) gave us the standard values for myelographic measurements with which we compared quantitatively the size of dural tube and spinal cord in the normal and abnormal groups. The abnormal group was classified into three types: type I was swollen spinal cord with normal dural tube; type II was swollen spinal cord with narrowed dural tube; and type III was normal spinal cord with narrowed dural tube. In conclusion myelography and myelographic measurements are essential for idiopathic scoliotic patients who will undergo spinal correction and fusion operations.     

Transient long thoracic nerve injury during posterior spinal fusion for adolescent idiopathic scoliosis: A report of two cases

We present the transient long thoracic nerve (LTN) injury during instrumented posterior spinal arthrodesis for idiopathic scoliosis. The suspected mechanism of injury, postoperative course and final outcome is discussed. The LTN is susceptible to injury due to its long and relatively superficial course across the thoracic wall through direct trauma or tension. Radical mastectomies with resection of axillary lymph nodes, first rib resection to treat thoracic outlet syndrome and cardiac surgery can be complicated with LTN injury. LTN injury producing scapular winging has not been reported in association with spinal deformity surgery. We reviewed the medical notes and spinal radiographs of two adolescent patients with idiopathic scoliosis who underwent posterior spinal arthrodesis and developed LTN neuropraxia. Scoliosis surgery was uneventful and intraoperative spinal cord monitoring was stable throughout the procedure. Postoperative neurological examination was otherwise normal, but both patients developed winging of the scapula at 4 and 6 days after spinal arthrodesis, which did not affect shoulder function. Both patients made a good recovery and the scapular winging resolved spontaneously 8 and 11 months following surgery with no residual morbidity. We believe that this LTN was due to positioning of our patients with their head flexed, tilted and rotated toward the contralateral side while the arm was abducted and extended. The use of heavy retractors may have also applied compression or tension to the nerve in one of our patients contributing to the development of neuropraxia. This is an important consideration during spinal deformity surgery to prevent potentially permanent injury to the nerve, which can produce severe shoulder dysfunction and persistent pain.     

Proton spin tomography in children and adolescents with so-called idiopathic scoliosis]

Somato-sensory evoked potentials (SSEP) were found to be pathological mostly in the lower extremities in 26 out of 45 children suffering from so called idiopathic scoliosis. We examined the vertebral spine and the spinal cord of 8 of them (with controlled SSEP-findings) by use of conventional MR-imaging and (where necessary) 3-dimensional-data-set following the Fournier-procedure. 6 of the 8 children showed alterations as follows: 1. A lipoma spreading partly extra-, partly intraspinally. 2. Subligamentous protrusions of the intervertebral disc (2 patients). 3. Dysraphic processes (2 patients). 4. An abnormally cranial ending myelon surrounded by a widened spinal channel. The findings are demonstrated and discussed concerning the questions whether the pathological SSEP and, furthermore, the deformity of the vertebral spine could be explained thereby. We are at least able to prove that some of the children with so called idiopathic scoliosis show pathological evoked potentials and MRI-findings.     

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

BACKGROUND: The prevalence of intraspinal pathology associated with scoliosis has been reported to be as high as 26% in some series, and, on the basis of this finding, preoperative magnetic resonance imaging is used in the screening of patients with adolescent idiopathic scoliosis. However, this practice continues to be highly controversial. In order to better resolve this issue, we performed what we believe to be the largest prospective study to evaluate the need for preoperative magnetic resonance imaging in patients with adolescent idiopathic scoliosis requiring arthrodesis of the spine. METHODS: A total of 327 consecutive patients with adolescent idiopathic scoliosis were evaluated between December 1991 and March 1999. All patients in the study presented with an adolescent idiopathic scoliosis curve pattern and had a complete physical and neurologic examination. Magnetic resonance imaging of the brain and the spinal cord were performed as part of their preoperative work-up. RESULTS: Seven patients had an abnormality noted on magnetic resonance imaging. These abnormalities included a spinal cord syrinx in two patients (0.6%) and an Arnold-Chiari type-I malformation in four (1.2%). One patient had an abnormal fatty infiltration of the tenth thoracic vertebral body. No patient required neurosurgical intervention or additional work-up. All patients who underwent spinal arthrodesis with segmental instrumentation tolerated the surgery without any immediate or delayed neurologic sequelae. CONCLUSIONS: The fact that magnetic resonance imaging did not detect any important pathology in the large number of patients in this study strongly suggests that magnetic resonance imaging is not indicated prior to arthrodesis of the spine in patients with an adolescent idiopathic scoliosis curve pattern and a normal physical and neurologic examination.     

Rotation of the spinal cord in idiopathic scoliosis

We undertook a radiographic analysis with pre-operative computed tomographic myelography in 78 patients with idiopathic scoliosis in order to analyse rotation of the spinal cord and to investigate its clinical significance. The angle of rotation of the cord had a statistically significant relationship to both that of the apical vertebra and the size of the primary curve. The relationship between the rotation of the cord and that of the apical vertebra was divided into three types. The cord rotated in the same direction as the apical vertebra in 55 patients and rotated in the opposite direction in the remaining 23 patients. In the first group, the angle of rotation of the cord was more than that of the vertebra in six patients, but less than it in 49 patients. These results suggest that the neuraxis in idiopathic scoliosis may be under tension in the axial dimension.     

Correlation between curve severity, somatosensory evoked potentials, and magnetic resonance imaging in adolescent idiopathic scoliosis.

STUDY DESIGN: A prospective study in patients with adolescent idiopathic scoliosis of different clinical severity using whole-spine magnetic resonance imaging and somatosensory evoked potentials. OBJECTIVES: To correlate the presence of magnetic resonance imaging structural abnormalities with somatosensory evoked potential-detected functional disorders in the hind brain and spinal cord and the Cobb's angle in patients with adolescent idiopathic scoliosis and to compare the result with those in healthy matched control subjects. SUMMARY OF BACKGROUND DATA: Many different types of neurologic dysfunction have been reported in scoliosis. With the advent of magnetic resonance imaging, there are increased reports on the association of idiopathic scoliosis and syringomyelia, Chiari I malformation, or tonsillar ectopia. The actual link between structural and functional disorder in idiopathic scoliosis is, however, unclear. METHODS: Posterior tibial nerve evoked potentials and whole-spine magnetic resonance imaging were performed in 36 healthy control subjects, 135 patients with adolescent idiopathic scoliosis with Cobb's angle less than 45 degrees, and 29 patients with Cobb's angle more than 45 degrees. RESULTS: Tonsillar ectopia or syringomyelia, detected by magnetic resonance imaging, or functional disturbance in the somatosensory pathway, detected by somatosensory evoked potentials, was found to be significantly more frequent in the group of patients with severe scoliosis curvature, with an incidence of 31% and 27.6%, respectively. Incidence of tonsillar ectopia was 33.3% in patients with abnormal somatosensory evoked potentials in contrast to the much lower incidence of 2.9% in patients with normal somatosensory evoked potentials. There was a significant structural and functional link. The incidence of syringomyelia in patients with and without tonsillar ectopia was 33.3% and 0.7%, respectively. CONCLUSIONS: In patients with adolescent idiopathic scoliosis with severe curve, the significant association with tonsillar ectopia and abnormal somatosensory function points to a neural origin. Disorders in the somatosensory function may be one of the mechanisms linking tonsillar ectopia to scoliosis. Somatosensory evoked potentials and magnetic resonance imaging may have important diagnostic and predictive value and may help in the management of adolescent idiopathic scoliosis.     

Magnetic resonance imaging of the brain stem in adolescent idiopathic scoliosis

The cause of adolescent idiopathic scoliosis remains an enigma. Several studies have demonstrated abnormalities of posture, proprioception, and equilibrium control in patients with adolescent idiopathic scoliosis. These functions are integrated by structures in and around the brain stem. Twenty-seven patients with adolescent idiopathic scoliosis were studied with magnetic resonance imaging to delineate the anatomy of the brain stem in such patients. Imaging was conducted from the hypothalamus to the spinal cord at C3 in 26 patients; the remaining patient underwent an incomplete study because of a claustrophobic reaction. The study group consisted of 25 females and 2 males with an average age of 16 + 5 years. There were 19 right thoracic curves, 5 thoracolumbar curves, and 3 left lumbar curves. The mean primary curve size was 27 degrees at the most recent clinical evaluation. Seven patients were treated with observation, 14 with bracing, and 6 with surgery. The magnetic resonance imaging studies were read independently by three attending radiologists in a randomized, blinded fashion along with the magnetic resonance imaging studies of 11 controls. Asymmetry in the ventral pons or medulla in the area of the corticospinal tracts was noted in seven study patients and one control; one study patient had an enlarged cisterna magna and one an inconclusive (incomplete) study. These findings may support previous studies that have suggested a central nervous system abnormality as a cause of adolescent idiopathic scoliosis.