Scoliosis may be the first symptom of the tethered spinal cord

Background:

Tethered cord syndrome (TCS) is a progressive clinical entity that arises from abnormal spinal cord tension. Scoliosis may be a unique symptom in TCS. The aim of this study is to investigate prognosis after releasing the filum terminale in scoliosis due to TCS with/without findings in magnetic resonance imaging (MRI) and to draw attention to the importance of somatosensorial evoked potentials (SSEP) on the differential diagnosis of idiopathic scoliosis versus scoliosis due to TCS with normal appearance of filum terminale and conus medullaris.

Materials and Methods:

Eleven female and seven male patients with progressive scoliosis were included in the study. They were evaluated radiologically, SSEP and urodynamical studies. Preoperative and postoperative anteroposterior full spine X-rays were obtained for measuring the Cobb''s angle. MRI was performed in all cases for probable additional spinal abnormalities. All patients underwent filum terminale sectioning through a L5 hemilaminectomy. The resected filum terminale were subjected to histopathological examination.

Results:

The mean Cobb angle was 31.6° (range 18°–45°). Eight patients (44.45%) had a normal appearance of filum terminale and normal level conus medullaris in MRI, but conduction delay and/or block was seen on SSEP. In the histopathological examination of filum terminale dense collagen fibers, hyaline degeneration and loss of elastic fibers were observed. Postoperatively none of the patients showed worsening of the Cobb angle. Three patients showed improvement of scoliosis.

Conclusion:

In TCS presented with scoliosis, untethering must be performed prior to the corrective spinal surgery. Absence of MRI findings does not definitely exclude TCS. SSEP is an important additional guidance in the diagnosis of TCS. After untethering, a followup period of 6 months is essential to show it untethering helps in stopping the progress of the scoliotic curve. In spite of non progression (curve stopped lesser than 45°) or even improvement of scoliosis, there may be no need for major orthopedic surgical intervention.     

"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.     

Fulcrum-bending像与伴发脊髓空洞或(和)Chiari畸形脊柱侧凸的手术治疗

[目的]探讨Fulcrum-bending(支点弯曲位)像对伴发Chiari畸形和(或)脊髓空洞的脊柱侧凸手术治疗的帮助及新思路,并分析手术疗效。[方法]18例伴发脊髓空洞和(或)Chiari畸形的脊柱侧凸患者的治疗方案分两组:(1)牵引后前后路联合脊柱侧凸矫形手术(6例):对脊柱侧凸有手术矫形指征、伴发无明显神经损害的Chiari畸形和(或)脊髓空洞者,先行Halo颅骨牵引,1周后行脊柱侧凸矫形手术;(2)直接行后路脊柱侧凸矫形手术(12例):术前拍Fulcrum-bending像,并根据其结果对脊柱侧凸进行矫形。[结果]6例牵引后手术患者Cobb’s角平均矫正率为61%;6例柔软型侧凸患者直接后路手术患者均未出现神经并发症,Cobb’s角平均矫正率为60%,且术前Fulcrum-bending像与术后Cobb’s角相接近;6例僵硬型侧凸患者中1例出现轻微神经损害情况,后逐渐恢复,Cobb’s角平均矫正率为52%,手术存在过度矫正。[结论]对无明显神经损害的伴发脊髓空洞或ChiariI型畸形的脊柱侧凸柔软患者,不必行术前牵引而直接行后路手术,且可以获得与牵引后前后路联合手术类似的矫形效果。     

Terminal ventriculostomy as an adjuvant treatment of complex syringomyelia: a case report and review of the literature

Complex syringomyelia is multifactorial, and treatment strategies are highly individualized. In refractory cases, sectioning of the filum terminale, also known as terminal ventriculostomy, has been described as a potential adjuvant treatment to alleviate syrinx progression. A 10-year-old boy with a history of arachnoiditis presented with complex syringomyelia, progressive lower extremity motor weakness, and spasticity. Previously, he had failed spinal cord detethering and direct syrinx shunting. Imaging studies demonstrated a holocord syrinx extending to the level of his conus medullaris and into the filum terminale. The patient underwent an uncomplicated lumbar laminectomy and transection of the filum terminale. Operative pathologic specimens demonstrated a dilated central canal within the filum. Postoperative imaging demonstrated significant reduction in the diameter of the syrinx. At follow-up, the patient’s motor symptoms had improved. Terminal ventriculostomy may be a useful adjuvant in treating caudally placed syringes refractory to other treatments. This procedure carries low neurological risk and involves no hardware implantation. In select cases, terminal ventriculostomy may help preserve neurological function in the face of otherwise progressive syringomyelia.     

Syringomyelia and Arnold Chiari in scoliosis initially classified as idiopathic: Experience with 25 patients

The authors analysed the clinical and radiological findings and the surgical management of 25 patients admitted for scoliosis classified as idiopathic at first presentation, but in fact associated with spinal cord and/or brain stem anomalies. Twenty patients had syringomyelia, 19 had Chiari malformation. Scoliosis was the only presenting symptom when all these patients were referred to the orthopaedic surgeon. On examination, five patients had normal neurological findings, while the others showed very mild neurological deficits. The diagnosis of syringomyelia and Chiari malformation was established by MRI, which is the best form of neuroradiological examination for discovering spinal abnormalities. Neurosurgical treatment is strongly recommended as the first step in the management of “pseudo” idiopathic scoliosis.     

节段性椎弓根钉系统治疗伴发脊髓空洞的脊柱侧凸

目的 评价节段性椎弓根钉系统治疗伴发脊髓空洞的脊柱侧凸的手术疗效.方法 应用节段性椎弓根钉系统治疗伴发脊髓空洞的脊柱侧凸35例.合并Chiari Ⅰ型畸形12例(34.3%).典型侧凸18例,不典型侧凸 17例.所有患者术前均未接受任何针对脊髓卒洞的治疗措施.手术分组:(1)一次手术组(30例):患者手术年龄>10岁,一次性后路节段性椎弓根钉系统矫形内固定植骨融合术.(2)二次手术组(5例):患者年龄≤10岁,一期手术行可自行延长的节段性椎弓根钉系统矫形手术,4～6年后行二期矫形内同定植骨融合术.结果 术前冠状面主弯Cobb角平均66.5°(32°～121°);术后平均22.6°(0°～78°),平均矫正率69.4%(31%～100%);平均随访58.4(13～113)个月,末次随访时冠状面主弯Cobb角3°～78°,平均25.9°.最终矫正率63.9%.6例随访时出现追加现象,其中5例融合下端椎没有融合至稳定椎.术后出现腹壁反射消失1例,浅感觉减退范围扩大1例,未予处理.结论 对于伴发未经治疗的非扩张型脊髓窄洞的脊柱侧凸,如果术前无或仅伴随轻微神经损害症状,可以直接采用后路节段性椎弓根钉系统进行矫形治疗.建议对这类脊柱侧凸远端应融合至稳定椎.     

Neuraxial analgesia during labor in a patient with Arnold-Chiari type I malformation and syringomyelia

Chiari type I malformation is a caudal displacement of the cerebellum with tonsillar herniation through the foramen magnum, frequently associated with syringomyelia, a syndrome characterized by cyst-like cavities in the spinal cord; each of the conditions leads to characteristic neurologic abnormalities. Pregnant patients with these types of malformation are considered to have an increased risk of brainstem compression and/or progression of the disease during labor. We present the case of a patient in labor with a diagnosis of syringomyelia associated with Chiari type I malformation and describe the anesthetic management. The patient revealed during labor that she had syringomyelia associated with Chiari type I malformation, after having made no mention of it in previous history taking. Finally, we review the pathology observed in these patients.     

Syringomyelia-associated scoliosis with and without the Chiari I malformation

Although there may be a hereditary component to true idiopathic scoliosis, the condition has no known cause and is not associated with dysraphism. However, scoliosis with an associated syrinx, with or without the Chiari I malformation, sometimes presents as an idiopathic-type curve. Physical examination findings and subtle clues on diagnostic imaging may help the orthopaedic surgeon diagnose scoliosis associated with syringomyelia. Examination findings include asymmetric reflexes and presentation at ages younger than those of patients who present with adolescent idiopathic curves (i.e., 10 to 14 years). Radiologic findings include kyphosis at the apex of the curve. Indications for surgical decompression include progressive neurologic deficits, weakness, pain, and progressive curves. Most orthopaedic surgeons agree that a syrinx should be evaluated neurosurgically before any planned spinal arthrodesis to decrease the risk of neurologic injury connected with surgical correction. The indications for arthrodesis in these patients compared with those with idiopathic curves are evolving.     

Intraspinal anomalies in scoliosis: An MRI analysis of 177 consecutive scoliosis patients

Background:

The association of intraspinal neural anomalies with scoliosis is known for more than six decades. However, there are no studies documenting the incidence of association of intraspinal anomalies in scoliotic patients in the Indian population. The guide lines to obtain an magnetic resonance imaging (MRI) scan to rule out neuro-axial abnormalities in presumed adolescent idiopathic scoliosis are also not clear. We conducted a prospective study (a) to document and analyze the incidence and types of intraspinal anomalies in different types of scoliosis in Indian patients. (b) to identify clinico-radiological ‘indicators’ that best predict the findings of neuro-axial abnormalities in patients with presumed adolescent idiopathic scoliosis, which will alert the physician to the possible presence of intraspinal anomalies and optimize the use of MRI in this sub group of patients.

Materials and Methods:

The data from 177 consecutive scoliotic patients aged less than 21 years were analyzed. Patients were categorized into three groups; Group A - congenital scoliosis (n=60), group B -presumed idiopathic scoliosis (n=94) and group C - scoliosis secondary to neurofibromatosis, neuromuscular and connective tissue disorders (n=23). The presence and type of anomaly in the MRI was correlated to patient symptoms, clinical signs and curve characteristics.

Results:

The incidence of intraspinal anomalies in congenital scoliosis was 35% (21/60), with tethered cord due to filum terminale being the commonest anomaly (10/21). Patients with multiple vertebral anomalies had the highest incidence (48%) of neural anomalies and isolated hemi vertebrae had none. In presumed ‘idiopathic’ scoliosis patients the incidence was higher (16%) than previously reported. Arnold Chiari-I malformation (AC-I) with syringomyelia was the most common neural anomaly (9/15) and the incidence was higher in the presence of neurological findings (100%), apical kyphosis (66.6%) and early onset scoliosis. Isolated lumbar curves had no anomalies. In group-C, incidence was 22% and most of the anomalies were in curves with connective tissue disorders.

Conclusion:

The high incidence of intraspinal anomalies in presumed idiopathic scoliosis in our study group emphasizes the need for detailed examination for subtle neurological signs that accompany neuro-axial anomalies. Preoperative MRI screening is recommended in patients with presumed ‘idiopathic’ scoliosis who present at young age, with neurological findings and in curves with apical thoracic kyphosis.     

Ependymoma of the filum terminale: Treatment and prognostic factors in a series of 28 cases

Summary A series of 28 ependymomas arising in the filum terminale was divided into two groups based on the presence/absence of connections with the conus medullaris and/or roots of the cauda equina. Group A comprised ependymomas having no connections with the contiguous structures and group B those either infiltrating or adhering to such structures.Factors having a positive influence on the prognosis (risk of recurrence) were: 1) clinical history under one year (p<0.01); 2) confinement of tumour to the filum terminale (p<0.01); 3) total tumour removal (p<0.05). Postoperative radiotherapy had no appreciable effect on outcome. The combination of significant factors was in turn significantly influenced by the mode of tumour growth, which proved to be the cardinal factor in prognosis. This point is examined in the light of the pulished work.     

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.     

Neurophysiological monitoring for safe surgical tethered cord syndrome release in adults

BACKGROUND: Release of tethered spinal cord by sectioning of the filum terminale carries a significant risk of injury to the neighboring motor and sensory nerve roots. Intraoperative neurophysiological monitoring techniques can help to minimize these adverse neurologic outcomes. METHODS: We performed a retrospective review of 67 consecutive patients undergoing tethered cord release. We excluded 52 pediatric patients which limited our study to 15 adult patients treated during a four year period, including patients with a thick filum, low lying conus, myelomeningocele, filum tumor, spinal cord malformation, and/or lipoma. Clinical outcomes were determined from postoperative follow-up visits. Two patients were lost to follow up and were excluded from the clinical outcome analysis. Electrical stimulation of the filum terminale and lumbo-sacral nerve roots in conjunction with electromyogram (EMG) recording was performed intraoperatively. RESULTS: The mean electrical threshold for EMG response during stimulation of the filum terminale was 37.1 volts (V), range 15 to 100 V. In comparison, the lowest threshold obtained by direct stimulation of the ventral nerve roots was a mean of 1.46 V, with a range of 0.1 to 7 V. More than 70% of the patients studied demonstrated a filum to motor root threshold ratio of 100:1 or greater. No patient developed new neurologic symptoms or signs postoperatively. Bowel and bladder function improved in 46% of patients, back pain in 39% and motor function in 31%. Eight percent reported decline in bladder control and worsening back pain postoperatively. CONCLUSIONS: The often dramatic difference in the threshold of the filum terminale and adjacent motor nerve roots (100:1) helps to identify, isolate, and safely section the filum terminale. Tethered cord release using intraoperative neurophysiological monitoring is safe and in the majority of cases leads to improvement or at least, stabilization of neurologic function. Monitoring prevented intraoperative nerve root injury that might have resulted in immediate onset of new neurologic deficits caused by the surgical procedure.     

Chiari I malformation associated with atlanto-axial dislocation: focussing on the anterior cervico-medullary compression

Summary Background. Chiari I malformation with atlantoaxial dislocation may cause both posterior and anterior cervicomedullary compression. We studied the clinicoradiological features and surgical outcome in patients having Chiari I malformation with atlantoaxial dislocation. Method. Thirty-nine patients with Chiari I malformation with atlanto-axial dislocation underwent preoperative and follow-up neurological status assessment. In Chiari I malformation with reducible atlanto-axial dislocation (n = 11), a direct posterior stabilization was done. In Chiari I malformation with irreducible atlanto-axial dislocation (n = 28), a single stage transoral decompression with posterior stabilization and/or posterior decompression and duraplasty were done in 18 patients. In 10 patients, only posterior decompression and/or posterior stabilization was performed. Seven among the latter patients subsequently deteriorated and required transoral decompression. Comparison of mean neurological status scores of patients with Chiari I malformation with irreducible atlanto-axial dislocation who underwent single stage transoral decompression with posterior stabilization versus the posterior procedure alone was done using T-test and proportional significance also calculated. Findings. Patients with Chiari I malformation with atlanto-axial dislocation have a high incidence of long tract signs and sphincteric disturbances with a decrease in the mean foramen magnum diameter. The mean neurological status scores of patients with Chiari I malformation with irreducible atlanto-axial dislocation who underwent single stage transoral decompression with posterior stabilization were significantly better than those patients who underwent the posterior procedure alone. The latter patients also showed significant clinical improvement following transoral decompression. In the presence of Chiari I malformation with reducible atlanto-axial dislocation, reduction and stabilization of atlanto-axial dislocation resulted in neurological improvement. The follow up neurological status scores of these patients improved after surgical intervention even in the presence of poor preoperative grades. Conclusions. Patients with Chiari I malformation should be investigated for the presence of atlanto-axial dislocation. In case atlantoaxial dislocation coexists, priority must be given to relieving anterior cervicomedullary compression.     

Transverse Microincisions of the Outer Layer of the Dura mater Combined with Foramen Magnum Decompression as Treatment for Syringomyelia with Chiari I Malformation

Summary Numerous surgical procedures have been proposed for treatment of syringomyelia associated with Chiari I malformation, but the optimal treatment has not yet been uniformly standardised. The main aim of the surgical treatment of syringomyelia/Chiari I complex is directed toward restoration of physiological cerebrospinal fluid dynamic at the craniovertebral junction. We report the surgical results of eight patients, affected by syringomyelia and Chiari I malformation, age range from 18 to 62 years, treated by bony foramen magnum decompression combined with transverse microincisions of the outer layer of the dura mater. In an average postoperative follow-up period of two years neurological symptoms and signs improved in seven patients. Postoperative Magnetic Resonance showed a decrease in size of the syrinx in seven patients. These results suggest that foramen magnum decompression combined with transverse microincisions of the outer layer of the dura 1) is an effective and safe treatment option for syringomyelia and Chiari I malformation, 2) corrects the circulatory disturbances of cerebrospinal fluid dynamic, 3) leads to a decrease in size of the syrinx and to a significant improvement in neurological signs and symptoms, 4) avoids complications of intradural approaches and syringosubarachnoid shunting.     

3D MRI在脊柱侧弯畸形矫形术前的临床应用价值

目的探讨3D MRI在脊柱侧弯患者矫形术前的临床应用价值。方法对100例脊柱侧弯患者行术前3DMR检查,采用3D-SPACE T2W序列,多平面重组图像,测量T4、顶椎、L1水平脊髓和椎体的轴位旋转角,观察测量所得顶椎脊髓旋转角与Cobb角的相关性,并进行统计学分析,对顶椎水平脊髓旋转与椎体旋转进行对比。结果顶椎水平脊髓旋转角与Cobb角存在相关性。顶椎水平脊髓旋转可分为3种类型,过度旋转型80例,旋转不足型13例,相反旋转型7例。35例患者最大脊髓旋转角不在顶椎水平。脊髓旋转与椎体旋转不同,在Cobb角大者,大部分脊髓旋转角度大于椎体旋转。MR检查发现2例合并多发神经纤维瘤,1例脊髓空洞,1例蝴蝶椎畸形,5例半椎体并蝴蝶椎畸形,1例合并腹股沟斜疝。结论脊髓、椎体旋转的大小及类型存在差异。脊柱侧弯患者常合并脊髓及椎体多发畸形,3DMR检查在脊柱侧弯畸形矫形术前评估中起着重要作用。     

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.     

Asymmetry of tonsillar ectopia,syringomyelia and clinical manifestations in adult Chiari I malformation

Background

The asymmetry of tonsillar ectopia, syringomyelia, and clinical manifestations, and their correlations in adult Chiari I malformation (CIM) are seldom discussed.

Methods

Clinical and imaging data of 104 consecutive adult patients with CIM and syringomyelia were retrospectively reviewed. A method was devised to quantify tonsillar and syrinx asymmetry. Correlations between the asymmetrically displaced cerebellar tonsils, the side of the syrinx, clinical presentations, and the curve direction of scoliosis were investigated.

Results

Tonsillar ectopia was left dominant in 46 patients (44.2 %), right dominant in 49 (47.1 %), and symmetrical in nine (8.7 %). The syrinx was left deviated in 44 patients (42.3 %), right deviated in 48 (46.2 %), and centrally located in 12 (11.5 %). A significant correlation was observed between the side of tonsillar herniation and the side of the syrinx (p?<?0.001), and also between the descending ratio of tonsillar herniation and the deviation ratio of the syrinx (p?<?0.001). The main side the of clinical presentations showed significant correlation with the dominant side of tonsillar herniation (p?=?0.009) and the side of syrinx deviation (p?=?0.012). In the 49 patients (47.1 %) with associated scoliosis, the curve direction was significantly related to not only the dominant side of tonsillar ectopia (p?=?0.0,28) but also the deviated side of the syrinx (p?=?0.044). Moreover, the curve magnitude was significantly correlated with the distance of the tonsillar herniation (p?=?0.001).

Conclusions

In adult CIM, most tonsillar herniations are asymmetrical and most syringomyelia is eccentrical. We speculate that the dominant side of tonsillar herniation determines the side of syrinx deviation, which in turn determines the main side of clinical presentations and the convex side of scoliosis. Our results suggest that the more the descended tonsil tilts to one side, the more the syrinx tilts to the same side.     

Prevalence and clinical significance of superficial abdominal reflex abnormalities in idiopathic scoliosis

To determine prevalence and significance of abnormal superficial abdominal reflexes (SARs) in idiopathic scoliosis. Study of 73 patients with presumed idiopathic scoliosis referred for magnetic resonance imaging (MRI), either as a routine pre-operative assessment (n=42) or because of abnormal symptoms or neurological signs (n=31). All patients were examined prior to magnetic resonance imaging (MRI), and the presence of abnormal SARs was noted. All patients then underwent MRI of the whole spine from the foramen magnum to the sacrum. The presence of Chiari 1 malformation and syrinx was recorded. The study group consisted of 11 males and 62 females with a mean age at time of MRI of 18 years (range 5–51 years) and a mean Cobb angle of 48° (range 10–104°). Abnormality of the SARs was recorded in eight cases (prevalence 11%). An abnormal MRI study was recorded in nine cases (12.3%), all patients having a syrinx and four having in addition, a Chiari 1 malformation. Of the patients with abnormal SARs, only 2 (25%) had an abnormal MRI study; 1 had unilateral absence of the reflexes whereas the other had complete absence of SARs. Of patients referred for MRI as a routine pre-operative assessment, 5 (11.6%) had an abnormal MRI study. In patients with idiopathic scoliosis, abnormality of the SARs was recorded in 11% of cases. Unilateral absence was present in one case only and was associated with the presence of syrinx. Other patterns of abnormality were not a useful indicator of underlying cord abnormality.     

Hydrosyringomyelia and its management in childhood

Syringomyelia, once regarded as a degenerative disease of adults, is now recognized to be a disorder usually associated with the Chiari malformation and occurring in patients of all ages. We have reviewed 47 patients with syringomyelia treated on the Neurosurgical Service at the Hospital for Sick Children during the years 1977 to 1985. Twelve of these patients had a Chiari I malformation, 30 had a Chiari II malformation, and 5 had an acquired Chiari malformation. Thirty-one of these patients were treated by decompression of the Chiari malformation and plugging of the obex, 5 were treated by a simple posterior fossa decompression, 9 were treated by shunting of the syringomyelic cavity, and 2 were treated by a combined decompression of the posterior fossa and shunting of the syrinx. The Gardner procedure (decompression of the Chiari malformation and plugging of the obex) was the procedure most commonly used in managing our group of patients and resulted in improvement in over 70% of patients.     

One-stage and posterior approach for correction of moderate to severe scoliosis in adolescents associated with Chiari I malformation: is a prior suboccipital decompression always necessary?

Priority of neurological decompression was regarded as necessary for scoliosis patients associated with Chiari I malformation in order to decrease the risk of spinal cord injury from scoliosis surgery. We report a retrospective series of scoliosis associated with Chiari I malformation in 13 adolescent patients and explore the effectiveness and safety of posterior scoliosis correction without suboccipital decompression. One-stage posterior approach total vertebral column resection was performed in seven patients with scoliosis or kyphosis curve >90° (average 100.1° scoliotic and 97.1° kyphotic curves) or presented with apparent neurological deficits, whereas the other six patients underwent posterior pedicle screw instrumentation for correction of spinal deformity alone (average 77.3° scoliotic and 44.0° kyphotic curves). The apex of the scoliosis curve was located at T7–T12. Mean operating time and intraoperative hemorrhage was 463 min and 5,190 ml in patients undergoing total vertebral column resection, with average correction rate of scoliosis and kyphosis being 63.3 and 71.1%, respectively. Mean operating time and intraoperative hemorrhage in patients undergoing instrumentation alone was 246 min and 1,450 ml, with the average correction rate of scoliosis and kyphosis being 60.8 and 53.4%, respectively. The mean follow-up duration was 32.2 months. No iatrogenic neurological deterioration had been encountered during the operation procedure and follow-up. After vertebral column resection, neurological dysfunctions such as relaxation of anal sphincter or hypermyotonia that occurred in three patients preoperatively improved gradually. In summary, suboccipital decompression prior to correction of spine deformity may not always be necessary for adolescent patients with scoliosis associated with Chiari I malformation. Particularly in patients with a severe and rigid curve or with significant neurological deficits, posterior approach total vertebral column resection is likely a good option, which could not only result in satisfactory correction of deformity, but also decrease the risk of neurological injury secondary to surgical intervention by shortening spine and reducing the tension of spinal cord.