Indications for magnetic resonance imaging in presumed adolescent idiopathic scoliosis

BACKGROUND: The use of magnetic resonance imaging has led to the diagnosis of abnormalities of the central nervous system associated with apparent idiopathic scoliosis. The indications for magnetic resonance imaging for presumed adolescent idiopathic scoliosis have not been established. METHODS: One thousand, two hundred and eighty children with presumed adolescent idiopathic scoliosis were evaluated over a ten-year period. Magnetic resonance imaging of the central nervous system (brainstem and spinal cord) was performed for specific patients, on the basis of the presence of selected indicators determined from the clinical history, physical examination, and plain radiographic examination of the spine. The medical records were reviewed to determine the specific indicators, the results of the imaging studies, and the subsequent treatment. RESULTS: Magnetic resonance imaging was ordered for 274 (21%) of the 1280 children who were evaluated. Abnormal findings were seen in twenty-seven (10%) of the 274 patients who underwent imaging, or 2% of the entire cohort. The most valuable single indicator of an abnormal finding on magnetic resonance imaging was absence of thoracic apical segment lordosis: eight of thirty-nine patients with that indicator had an abnormal finding on magnetic resonance imaging. The optimal diagnostic yield for a single category of indicators occurred when an atypical curve pattern was the only indicator: six of fifty-eight patients in whom this was the case had an abnormal finding on magnetic resonance imaging. None of the twenty children in whom pain was the only indicator category had an abnormal imaging study. The optimal diagnostic yield occurred when both an atypical curve pattern and neurological indicators were present: thirteen (25%) of fifty-three patients in whom this was the case had an abnormal finding on magnetic resonance imaging. Thirteen of the twenty-seven patients received surgical treatment for the abnormality of the central nervous system revealed by the imaging. CONCLUSIONS: The correct use of diagnostic tests is an important component of effective medical practice. An abnormality of the central nervous system is present in approximately 10% of patients with presumed adolescent idiopathic scoliosis in whom only subtle abnormalities are identified on the basis of the clinical history, physical examination, or radiographic examination. Knowledge of the diagnostic value of the specific clinical indicators, considered individually and in combination, can help the clinician to determine more effectively when advanced imaging of the central nervous system should be performed.     

Juvenile and adolescent idiopathic scoliosis: magnetic resonance imaging evaluation and clinical indications

The aims of this study were (1) to determine the rate of 'idiopathic' scoliosis associated with neuroanatomical abnormalities of the posterior cerebral fossa (PCF), spinal canal (SC) or central nervous system (CNS), and (2) to identify any clinical, neuro-orthopedic criteria, radiological curve pattern or other variable which could justify magnetic resonance imaging (MRI) as complementary study. Fifty-six patients with juvenile and adolescent scoliosis, were prospectively evaluated with MRI of the PCF and SC. All the patients were categorized into four different groups according to neuro-anatomical abnormalities on MRI (groups A, B, C and D). Eleven patients (19.6%) presented neuroanatomical abnormalities of the PCF and SC (group A), four patients (7.1%) presented pathological conditions of the CNS (group B) and three patients (5.4%) presented anomalies at the osseous spine and abdomen (group C). The remaining 38 patients (67.9%) presented with normal MRI results (group D). Of the patients in group A, 81.8% were neurologically normal. In this group, the right and left thoracic curve patterns were seen in the same number of patients (four of 11 each). Early diagnosis of neuroanatomical abnormalities of the PCF, SC and CNS could be achieved in 26.7% of cases (groups A and B). The most significant finding was the chronological age: 36.4% of patients in group A were under the age of 11 years. In addition, it would be recommended that in patients with scoliosis and a surgical indication, MRI results should be to take into consideration as a complementary preoperative evaluation because four of 15 patients (26.7%) with an indication for spinal fusion and who were neurologically normal, sustained some of the conditions included in groups A and B.     

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.     

全脊柱核磁共振成像法评估青少年特发性脊柱侧凸的可行性研究

目的 探讨全脊柱MRI检查法测量Cobb角的可行性.方法 2名研究者分别对60例青少年特发性脊柱侧凸(AIS)的后前位及侧位X线片和全脊柱MRI片测量主弯及次弯Cobb角、T5～T12后凸、顶椎旋转,记录测量时间和测量的上下端椎,2名研究者在1周后进行重复测量.对比X线片和MRI测量结果使用Pearson相关法,而研究者之间和研究者内部进行可靠性评估.结果 研究发现在所有X线片和MRI测量结果之间具有显著相关性(P=0.01);主弯Cobb角(R =0.912),代偿弯角度(R=0.826),后凸(R =0.939).X线片和MRI测量结果的研究者组间主弯Cobb角的可靠性分别是R=0.958,0.889;代偿弯Cobb角的可靠性分别是R=0.948,0.858;椎体旋转R=0.954是有显著性的.X线片和MRI测量结果的研究者组内主弯Cobb角的可靠性分别是R=0.965,0.966;代偿弯Cobb角R=0.949,0.944,均有显著性.结论 研究结果示MRI能够获得的冠状面和矢状面测量结果与传统X线片测量结果有高度相关性.另外,MRI除具有可靠的椎体旋转测量外,MRI最大优势就是无辐射,并可替代用于MS诊断性评估.     

Dural ectasia in adolescent idiopathic scoliosis: quantitative assessment on magnetic resonance imaging

To our knowledge, the assessment of dural sac diameters in patients with adolescent idiopathic scoliosis (AIS) is not reported in the literature. The aim of this study was to find out if, dural ectasia occurs more frequently among patients with AIS, to define cut-off values for dural sac ratio and test the validity of such values. A total of 126 spine MRIs (79 patients with AIS and 47 control subjects) were included in this retrospective analysis (age range 7–25 years, 62% were females). Dural sac diameter (DSD) and vertebral body diameter (VBD) were estimated and dural sac ratio (DSR = DSD/VBD) was calculated at T5 and L3. DSR at T5 and L3 were 0.69 ± 0.12, and 0.52 ± 0.10, respectively, in patients with AIS compared with 0.62 ± 0.11, and 0.44 ± 0.07, respectively, in controls (P = 0.001 at T5 and <0.001 at L3). Our estimated cut-off values for DSR were 0.84 and 0.58 at T5 and L3, respectively. This resulted in 100% sensitivity compared with 74% when using the cut-off values proposed by Oosterhof et al. No statistically significant association was found between the occurrence of dural sac enlargement in patients with AIS and the severity of scoliotic deformity, the apical vertebral rotation, epidural fat thickness, occurrence of pain, neurological deficit, atypical scoliosis or rapid curve progression. Females were affected more frequently than males. As dural sac enlargement means thinning of the pedicles, we believe that the findings of this study have important clinical implications on the preoperative workup of AIS.     

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

Purpose

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

Methods

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

Results

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

Conclusion

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

青少年特发性脊柱侧凸胸椎形态学的MRI测量及临床意义

目的 通过磁共振成像(MRI)观察青少年特发性脊柱侧凸(AIS)和正常同年龄组青少年胸椎的形态学差异,探讨其临床意义.方法 胸椎轻度侧凸(MS)组患者10例(Cobb角15°～39°),胸椎中度侧凸(SS)组患者10例(Cobb角40°～75°).另选健康青少年10名作为对照(非侧凸组).所有研究对象均为女性,年龄13～14岁.用1.5 T磁共振扫描仪(Sonata,Siemens,Erlanger,德国)对所有研究对象进行全脊柱矢状面扫描,在图像工作站(Easy Vision,Philips Medical Systems,Best,荷兰)上重建脊柱矢状面图像,测量每个胸椎椎体前壁高度,后壁高度,棘突间高度,在横截面测量椎体横径长度,并进行对比分析.结果 椎体前后高度、宽度从T1到T12逐渐增加,并呈线性分布,脊柱侧凸组椎体高度普遍>正常同年龄非侧凸组患者.脊柱侧凸组患者椎体高度横径比值以及脊椎前后高度比值均>无侧凸组.胸椎侧凸顶椎区T6～T9椎体前方高度、椎体高度横径比值以及脊椎前后高度比值,脊柱侧凸组明显>非侧凸组,差异均有统计学意义(P<0.05).结论 AIS胸椎侧凸女性患者胸椎顶椎区存在显著的脊柱生长模式异常,与正常胸椎相比AIS的胸椎更高、并显得更为瘦长.     

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.     

青少年特发性脊柱侧凸术后疗效的评估

青少年特发性脊柱侧凸（adolescent idiopathic scoliosis,AIS）是指一组青少年起病、不明病因的脊柱侧向弯曲大于10°伴有椎体旋转的三维脊柱畸形,发病率较高,严重危害青少年的身心健康。随着三维矫形理论和内固定器械的发展,AIS的治疗取得了长足进步。尤其是全椎弓螺钉固定技术的出现,大大提高了AIS手术的矫正率。然而,AIS的治疗应以追求患者生存质量的改善为最终目的,手术的矫正率并非越高越好,因此,全面评价AIS术后疗效应成为AIS手术治疗的一个重要部分,而全面的评价必须包括主客观两个方面的丰旨标．     

Classification of the adolescent idiopathic scoliosis and preoperative strategy]

The authors analysed 841 patients (83% girls and 17% boys) with adolescent idiopathic scoliosis. 678 patients (group I) were treated with the Harrington technique and 163 patients (group II) were treated using multisegmental instrumentation. Follow-up time in group I was on average 14.2 years, and 28 months in group II. Preoperative assessment of patients in group was based on clinical and radiological examination. Assessment of the spine was mainly based on coronal radiogram done in an upright position and lateral side-bending radiograms in a supine position. Traction and lateral X rays were rarely taken into account in this study. The fusion area was decided according to the end vertebrae of the structural curves. The caudal end of the fusion area was identified using Harrington's stable zone. The curves were classified in accordance with the SRS suggestions. Taking into account the apex of the curve, the deformations were classified into: cervico-thoracic, thoracic, thoraco-lumbar, lumbar and lumbo-sacral curves. In group II the triplanar (3D) character of the deformity was taken into account. In the coronal plane the upper and lower stable vertebra of the major structural curves were identified using the CSVL (Central Sacral Vertical Line) based on long films (70 cm x 110 cm) with and without traction. Lumbar curve was classified as mild, moderate, severe according to CSVL. In the axial plane vertebral rotation was assessed according to Nash and Moe method. A careful analysis of lateral radiograms in the upright standing position was performed. Lateral radiograms were performed also in maximal flexion and hyperextension of the spine to obtain a dynamic evaluation of the sagittal plane. Conoral radiograms with maximal rotation of the trunk to assess mobility of the caudad segments of the deformity. Classification of the scoliotic deformity based on its triplanar character included: thoracic curves (King III, IV, V types), double major (thoracic and lumbar), "false" double major curve (thoracic and lumbar) King type II, thoracolumbar/lumbar curves--the main curve is thoracolumbar lumbar/thoracolumbar curves--the main curve is lumbar--10 degrees the thoracolumbar component--King type I triple major curve--all curves have similar structural changes. Correct identification of the type of scoliosis, assessment of structural changes in the frontal, sagittal and axial plane (three dimensional 3D) and analysis of the size and correctiveness of the lumbar curve and all parameters which play a key role in rational preoperative planning. Redefining or at least maintaining lumbar lordosis is far more important than correction of thoracic kyphosis.     

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.     

CTM与MRI在评估青少年特发性脊柱侧凸顶椎置钉风险的差异性

[目的]比较脊髓造影计算机断层扫描(computed tomography myelography,CTM)检查技术与核磁共振成像技术(magnetic resonance imaging,MRI)在术前评估青少年特发性脊柱侧凸患椎置钉风险方面的优缺点。[方法]收集分析2009年1月²011年12月在本院行椎弓根螺钉手术治疗并有完整胸椎影像学资料的青少年特发性脊柱侧凸患者29例,其中CTM资料为21例,MRI资料为8例,分别测量两种影像学检查的各个横断面图像上的顶椎区脊髓中心到凸、凹侧硬膜囊及椎弓根内侧壁的距离,计算凸凹侧脊髓的偏移空间、凸凹侧椎弓根的最短直径,以及椎体和脊髓的旋转角度;并进行比较分析。阐述MRI和CTM在术前评估手术风险中的优劣势,和CTM检查相对于MRI检查的优越性。[结果]CTM和MRI两种检查技术的测量结果显示,凹侧硬膜囊及椎弓根内侧壁的距离、凸侧椎弓根直径、凹侧椎弓根直径的测量差异上有统计学意义(t=2.2,P<0.01;t=-2.9,P<0.01;t=-2.8,P<0.01);而在椎体旋转度、凸侧硬膜囊及椎弓根内侧壁的距离、脊髓的旋转度的测量上两种检查方式之间没有统计学意义(t=-1.1,P>0.01;t=0.9,P>0.01;t=0.3,P>0.01),由此可以看出CTM在评价骨性结构尤其是凹侧脊髓偏移空间、凸凹侧椎体直径的评价上有优势,而MRI在脊髓与椎体的旋转、凸侧脊髓偏移空间等测量中敏感性更高。[结论]CTM和MRI在临床上可以提供不同的参考价值,在反应凹侧脊髓偏移空间时,CTM的检查结果较MRI灵敏度更高,有临床价值;为提高顶椎置钉的安全性及减少术中的并发症,建议将CTM列为常规检查。     

青少年特发性脊柱侧凸校正身高的临床评估

青少年特发性脊柱侧凸(adolescent idiopathic scoliosis,AIS)是一种三维结构性脊柱畸形,冠状面上侧凸、矢状面上胸椎后凸的减少甚至前凸以及水平面上椎体的旋转及楔形变都可能影响患者的身高,且身高的丢失随着侧凸的进展而加重,尤其当存在冠状面及矢状面失衡、躯干塌陷时,身高改变更为明显.     

The clinical role of preoperative fulcrum-bending and supine side-bending radiographs on the prediction of curve correction in adolescent idiopathic scoliosis

European Spine Journal - Preoperative curve assessment is important in adolescent idiopathic scoliosis (AIS). Our objective is to clarify the role of side-bending radiographs (SBR) and...