脊髓型颈椎病手术前后MRI的研究

目的：评价脊髓型颈椎病手术前后MRI表现及临床意义。方法：46例患者颈前路手术前后均行MRI的检查,按脊髓的受压程度及脊髓内信号改变分类,观察比较术前和术后MRI的变化与临床表现的关系。结果：脊髓受压程度与临床症状的严重程度密切相关,受压程度越重,临床表现越重（P＞0．05）,术后脊髓形态无恢复、髓内高信号未消失者术后恢复差。高信号消失或明显降低者术前症状轻,手术效果较好。结论：MRI对脊髓型颈椎病预后判断有重要意义。     

Prognostic relevance of the postoperative evolution of intramedullary spinal cord changes in signal intensity on magnetic resonance imaging after anterior decompression for cervical spondylotic myelopathy

OBJECT: Areas of intramedullary signal intensity changes (hypointensity on T1-weighted magnetic resonance [MR] images and hyperintensity on T2-weighted MR images) in patients with cervical spondylotic myelopathy (CSM) have been described by several investigators. The role of postoperative evolution of these alterations is still not well known. METHODS: A total of 47 patients underwent MR imaging before and at the end of the surgical procedure (intraoperative MR imaging [iMRI]) for cervical spine decompression and fusion using an anterior approach. Imaging was performed with a 1.5-tesla scanner integrated with the operative room (BrainSuite). Patients were followed clinically and evaluated using the Japanese Orthopaedic Association (JOA) and Nurick scales and also underwent MR imaging 3 and 6 months after surgery. RESULTS: Preoperative MR imaging showed an alteration (from the normal) of the intramedullary signal in 37 (78.7%) of 47 cases. In 23 cases, signal changes were altered on both T1- and T2-weighted images, and in 14 cases only on T2-weighted images. In 12 (52.2%) of the 23 cases, regression of hyperintensity on T2-weighted imaging was observed postoperatively. In 4 (17.4%) of these 23 cases, regression of hyperintensity was observed during the iMRI at the end of surgery. Residual compression on postoperative iMRI was not detected in any patients. A nonsignificant correlation was observed between postoperative expansion of the transverse diameter of the spinal cord at the level of maximal compression and the postoperative JOA score and Nurick grade. A statistically significant correlation was observed between the surgical result and the length of a patient's clinical history. A significant correlation was also observed according to the preoperative presence of intramedullary signal alteration. The best results were found in patients without spinal cord changes of signal, acceptable results were observed in the presence of changes on T2-weighted imaging only, and the worst results were observed in patients with spinal cord signal changes on both Tl- and T2-weighted imaging. Finally, a statistically significant correlation was observed between patients with postoperative spinal cord signal change regression and better outcomes. CONCLUSIONS: Intramedullary spinal cord changes in signal intensity in patients with CSM can be reversible (hyperintensity on T2-weighted imaging) or nonreversible (hypointensity on T1-weighted imaging). The regression of areas of hyperintensity on T2-weighted imaging is associated with a better prognosis, whereas the T1-weighted hypointensity is an expression of irreversible damage and, therefore, the worst prognosis. The preliminary experience with this patient series appears to exclude a relationship between the time of signal intensity recovery and outcome of CSM.     

Significance of CSF area measurements in cervical spondylitic myelopathy

Mild clinical myelopathy can occur without cord compression, and asymptomatic cord compression seen on MRI is common. The aim of this study was to ascertain the MRI features which best correlate with early clinical myelopathy. The study was conducted on three groups: group A, 20 patients with clinical myelopathy and MRI evidence of cervical spondylosis; group B, 20 patients without myelopathy, but with other clinical and MRI evidence of cervical spondylosis; and group C, 10 normal volunteers with no MRI evidence of spondylosis. The cross-sectional area (CSA) of the spinal cord (SP-CSA), spinal canal (SC-CSA) and CSF space (CSF-CSA) were measured on T1-weighted axial images at the level of the most severe spinal canal stenosis. The severity of myelopathy was assessed using a simple scoring system giving a score from 0 (normal) to 11 (severe). Subjective demonstration of cord compression on sagittal images was an insensitive indicator of clinical myelopathy. All three measures of cross-sectional area were significantly smaller in Group A than in B (p<0.01). The reduction in SP-CSA was the only independent prognosticator for severity of myelopathy (p<0.005) accounting for 63% of the variation in myelopathy score. All three variables showed a significant correlation with the presence of myelopathy (p<0.01); however, logistic regression analysis showed a decrease in CSF-CSA to be the only independent significant prognosticator of the presence of clinical myelopathy (p<0.02). Reduction of the CSF space to less than 0.7 cm2 was associated with a 90% chance of clinical myelopathy (specificity 83%).     

Increased MR signal intensity due to cervical myelopathy. Analysis of 29 surgical cases

The cases of 29 patients with cervical myelopathy, who had been treated by anterior spine fusion, were reviewed. The relationship between pre- and postoperative magnetic resonance (MR) images was investigated with special reference to increased signal intensity in the spinal cord on the T2-weighted images and the relevance of this finding to clinical conditions. Preoperatively, there were areas of increased signal intensity in 12 patients whereas there were no areas of increased signal intensity in the other 17. The lesions were not clearly demonstrated on T1-weighted images. The pre- and postoperative clinical condition of the patients whose preoperative MR images showed areas of increased signal intensity in the spinal cord on T2-weighted images was worse than that of the patients who did not have areas of increased signal intensity. Of the 12 patients with regions of increased signal intensity preoperatively, five showed decreased signal intensity postoperatively compared to the preoperative levels and seven had no change. The postoperative recovery of the five patients who showed decreased signal intensity postoperatively was better than that of the seven patients who exhibited no change. The areas of increased MR signal in the spinal cord might be due to edema, cord gliosis, demyelination, or microcavities.     

Effect of intramedullary signal changes on the surgical outcome of patients with cervical spondylotic myelopathy.

BACKGROUND CONTEXT: Intramedullary signal intensity changes on magnetic resonance imaging (MRI) in cervical spondylotic myelopathy are thought to be indicative of the prognosis. However, the prognostic significance of signal intensity changes remains controversial. PURPOSE: To determine the radiographic and clinical factors that correlate with the prognosis after surgery in patients with cervical spondylotic myelopathy and to investigate the factors affecting the outcome of intramedullary signal changes on MRI. STUDY DESIGN: A prospective study evaluating clinical parameters and MRI in consecutive patients operated on for cervical spondylotic myelopathy. PATIENT SAMPLE: A total of 146 consecutive patients with cervical spondylotic myelopathy operated on during a 2-year period (September 1999 to September 2001) formed the study group. OUTCOME MEASURES: Age, duration of symptoms, number of cervical prolapsed intervertebral discs, surgical approach, preoperative signal changes, residual compression and postoperative outcome of signal changes; clinical outcome (motor, sensory, autonomic and disability improvement). METHODS: The participants in this study underwent anterior cervical discectomy/corpectomy or laminectomy/laminoplasty for cervical spondylotic myelopathy. Clinical features and MRI findings were studied in detail and compared with postoperative clinical and radiological status. The spinal cord signal intensity changes were evaluated before and after surgery. The multifactorial effect of such variables as age, duration of symptoms, number of prolapsed intervertebral discs, surgical approach (anterior/posterior), preoperative cord changes on T1- and T2-weighted sequences and persistence/regression of cord changes on clinical outcome (motor/sensory/autonomic/disability improvement) was studied using stepwise logistic regression. The highlight of the study is the analysis of the factors affecting regression of cord changes and their effect on postoperative outcome. RESULTS: Preoperative intramedullary signal changes were present in 121 of 146 patients (82.9%); of these 121 patients, T1- and T2-weighted images were present in 81, and T2-weighted images were present in 40 (no patient had isolated T1 change). Postoperative MRI could be obtained in 44 of 121 patients (36.4%) with preoperative intramedullary signal changes; 14 had regression of cord changes. There was no significant difference in the clinical presentation of patients with and without cord changes. There was a significant correlation between the surgical outcome of patients and their age, duration of symptoms, number of cervical prolapsed intervertebral discs, surgical approach, preoperative signal changes, residual compression and postoperative outcome of signal changes. The patients with no intramedullary signal changes and signal changes only on T2-weighted images had a better outcome than patients with signal changes on both T1- and T2-weighted images. The patients with regression of intramedullary signal changes had significantly better outcome. There was no significant correlation between regression of signal changes and other factors. However, chronicity of disease, multiplicity of discs and postoperative residual compression relatively affect persistence of intramedullary signal changes. CONCLUSIONS: The presence of intramedullary signal changes on T1- as well as T2-weighted sequences on MRI in patients with cervical spondylotic myelopathy indicates a poor prognosis. However, the T2 signal intensity changes reflect a broad spectrum of spinal cord reparative potentials. Predictors of surgical outcomes are preoperative signal intensity change patterns of the spinal cord and their postoperative persistence/regression on radiological evaluations, age at the time of surgery, multiplicity of involvement and chronicity of the disease and surgical approach (anterior/posterior).     

Histopathologic correlation of magnetic resonance imaging signal patterns in a spinal cord injury model

Magnetic resonance imaging (MRI) provides a noninvasive method of monitoring the pathologic response to spinal cord injury. Specific MR signal intensity patterns appear to correlate with degrees of improvement in the neurologic status in spinal cord injury patients. Histologic correlation of two types of MR signal intensity patterns are confirmed in the current study using a rat animal model. Adult male Sprague-Dawley rats underwent spinal cord trauma at the midthoracic level using a weight-dropping technique. After laminectomy, 5- and 10-gm brass weights were dropped from designated heights onto a 0.1-gm impounder placed on the exposed dura. Animals allowed to regain consciousness demonstrated variable recovery of hind limb paraplegia. Magnetic resonance images were obtained from 2 hours to 1 week after injury using a 2-tesla MRI/spectrometer. Sacrifice under anesthesia was performed by perfusive fixation; spinal columns were excised en bloc, embedded, sectioned, and observed with the compound light microscope. Magnetic resonance axial images obtained during the time sequence after injury demonstrate a distinct correlation between MR signal intensity patterns and the histologic appearance of the spinal cord. Magnetic resonance imaging delineates the pathologic processes resulting from acute spinal cord injury and can be used to differentiate the type of injury and prognosis.     

Clinical value of magnetic resonance imaging for cervical myelopathy

The magnetic resonance imaging (MRI) findings in 115 cases of cervical myelopathy, 121 cases of cervical radiculopathy, and 64 cases of neck pain with no neurologic deficit were prospectively studied to investigate the clinical value of MRI for cervical myelopathy. The MRI findings in the T1-weighted sagittal projection were classified into four groups according to the degree of the compressed deformities of the cervical cord. The degree of compression of the cervical cord on MRI findings showed a significant correlation with the severity of myelopathy, the anteroposterior diameter of the spinal column, and the degree of compression of the dural tube in the myelograms (P less than 0.01). Fifty-one patients of cervical myelopathy had undergone both preoperative and postoperative MRI. Of these, the spinal canal of 47 patients that was well decompressed was recognized according to plain computed tomography (CT). However, 24 (51%) of these 47 patients showed on MRI a deformity in the spinal cord amounting to cord atrophy. The correlation between the clinical function of the spinal cord and the recovery of the cord deformity on MRI at the operative levels was accurately investigated in 34 patients who had no cord deformities in the adjacent intervertebral levels. Twenty patients with cord atrophy had slightly poor clinical results, although no significant difference was found between these 20 and 14 patients with recovery in the cord deformities. From these results, it was evident that T1-weighted MRI is useful in the accurate diagnosis of compression myelopathy, in accurately deciding the level of the disease focus, and in the accurate assessment of the surgical results.     

A case of cervical subpial lipoma

The authors report the rare case of a 48-year-old woman with a cervical subpial lipoma unassociated with spinal dysraphism. Her symptoms were progressive weakness and numbness in the four extremities and the neurological symptom of mild cervical myelopathy. Plain radiographs of the cervical spine showed diffuse widening of the spinal canal, which was occupied by a large low-density mass revealed by axial CT scan. MR imaging identified the mass as being dorsolateral to the cord in the intradural region. It was hyperintense on both T1- and T2-weighted images. Axial images with fat suppression sequence clearly showed dorsal nerve roots traveling through the lesions, but the interface between the spinal cord and lesion was not well demarcated. A cervical laminectomy between C3-6 revealed a yellowish subpial mass after the dura was opened. The mass was only partially resected and intraoperative SEP monitoring data remained normal including N20 latency. Histological examination found mature adipose tissue covered by thickened pia mater, which was compatible with a diagnosis of lipoma. After surgery, no complications occurred and the patient's myelopathy subsequently improved. Subpial spinal lipomas unassociated with dysraphism are uncommon and they are reported in only 1% of all spinal cord tumors. They are thought to arise from premature dysjunction of the cutaneous ectoderm during neural tube formation. Without any invasive procedure, MR imaging is indispensable to show their longitudinal dimension as well as their infiltrative extension into the spinal cord. The main purpose of surgery is to decompress the lipoma from the adjacent neural structures, because it is benign in nature and there is no cleavage plane identifiable between the lipoma and the spinal cord.     

Boomerang deformity of cervical spinal cord migrating between split laminae after laminoplasty

Patients with cervical compression myelopathy were studied to elucidate the mechanism underlying boomerang deformity, which results from the migration of the cervical spinal cord between split laminae after laminoplasty with median splitting of the spinous processes (boomerang sign). Thirty-nine cases, comprising 25 patients with cervical spondylotic myelopathy, ¶8 patients with ossification of the posterior longitudinal ligament, and 6 patients with cervical disc herniation with developmental canal stenosis, were examined. The clinical and radiological findings were retrospectively compared between patients with (B group, 8 cases) and without (C group, 31 cases) boomerang sign. Moderate increase of the grade of this deformity resulted in no clinical recovery, although there was no difference in clinical recovery between the two groups. Most boomerang signs developed at the C4/5 and/or C5/6 level, where maximal posterior movement of the spinal cord was achieved. Widths between lateral hinges and between split laminae in the B group were smaller than in the C group. Flatness of the spinal cord in the B group was more severe than in the C group. In conclusion, the boomerang sign was caused by posterior movement of the spinal cord, narrower enlargement of the spinal canal and flatness of the spinal cord.     

Functional diagnosis using multimodal spinal cord evoked potentials in cervical myelopathy

The electrophysiological measurement of spinal cord evoked potentials (SCEPs) has been established as a tool for diagnosing the spinal level responsible for cervical myelopathy. Only a few studies, however, employed multimodal SCEPs for this purpose. The objective of this study was to investigate the correlation between multimodal SCEPs recorded during cervical laminoplasty and magnetic resonance imaging (MRI) abnormalities in 18 patients aged 70 years and older versus 32 patients less than 65 years of age. Both the SCEPs and MRIs showed higher incidences of multiple-level cord involvement in the older group than in the younger group. Discrepancies in the spinal levels involved between the SCEPs and the MRIs were found in 12 patients (67%) for the older group and 6 patients (19%) for the younger group. The accuracy of the MR images in localizing the lesion site was significantly lower in the older group than in the younger group, indicating that MR images tend to show clinically silent cord compression in elderly patients. Because spinal cord compression can appear without functional change in elderly patients, electrophysiological evaluations with intraoperative multimodal SCEP studies are a useful addition to MRI for understanding the pathology of myelopathy.     

脊髓型颈椎病术后MRI脊髓高信号改变与疗效的关系

目的 探讨脊髓型颈椎病术后MR T2WI脊髓高信号改变与疗效的关系.方法 功会26例脊髓型颈椎病患者,男15例,女11例;年龄38~73岁,平均49.8岁.收集患者术前和术后3个月以上脊髓MRI矢状位T2WI照片,用Yukawa法对脊髓信号强度进行评分,对照观察手术前后脊髓高信号变化情况.分别测量轴位T2WI压迫最重节段手术前后的脊髓横截面积.应用JOA17分法评价术前及术后脊髓功能,分析脊髓高信号改变与术后神经功能变化的关系.结果 根据手术后脊髓高信号变化将患者分为3组:脊髓高信号减弱组18例,脊髓高信号不变组7例,脊髓高信号增强组1例.脊髓高信号减弱组与不变组术前脊髓信号评分比较,差异无统计学意义.脊髓高信号减弱组与不变组术前脊髓信号评分与术后JOA评分、神经功能改善率均无相关性.两组相比,脊髓高信号减弱组年龄小[(51.94±11.04):(61.12±10.14),P=0.048]、术前脊髓受压最重节段横截面积大[(60.90±14.77):(42.05±18.05),P=0.010]、术后JOA评分高[(14.44±1.82):(11.00±3.89),P=0.042]、神经功能改善率高[(64%±23%):(38%±30%),P=0.027].脊髓高信号增强组因例数少,未列入对比研究.结论 脊髓型颈椎病术后MR T2WI脊髓高信号改变可作为疗效预测指标.     

Postoperative changes in spinal cord signal intensity in patients with cervical compression myelopathy: comparison between preoperative and postoperative magnetic resonance images

OBJECT: Increased signal intensity of the spinal cord on magnetic resonance (MR) imaging was classified pre- and postoperatively in patients with cervical compressive myelopathy. It was investigated whether postoperative classification and alterations of increased signal intensity could reflect the postoperative severity of symptoms and surgical outcomes. METHODS: One hundred and four patients with cervical compressive myelopathy were prospectively enrolled. All were treated using cervical expansive laminoplasty. Magnetic resonance imaging was performed in all patients preoperatively and after an average of 39.7 months postoperatively (range 12-90 months). Increased signal intensity of the spinal cord was divided into 3 grades based on sagittal T2-weighted MR images as follows: Grade 0, none; Grade 1, light (obscure); and Grade 2, intense (bright). The severity of myelopathy was evaluated according to the Japanese Orthopedic Association (JOA) score for cervical myelopathy and its recovery rate (100% = full recovery). RESULTS: Increased signal intensity was seen in 83% of cases preoperatively and in 70% postoperatively. Preoperatively, there were 18 patients with Grade 0 increased signal intensity, 49 with Grade 1, and 37 with Grade 2; postoperatively, there were 31 with Grade 0, 31 with Grade 1, and 42 with Grade 2. The respective postoperative JOA scores and recovery rates (%) were 13.9/56.7% in patients with postoperative Grade 0, 13.2/50.7% in those with Grade 1, and 12.8/40.1% in those with Grade 2, and these differences were not statistically significant. The postoperative increased signal intensity grade was improved in 16 patients, worsened in 8, and unchanged in 80 (77%). There was no significant correlation between the alterations of increased signal intensity and surgical outcomes. CONCLUSIONS: The postoperative increased signal intensity classification reflected postoperative symptomatology and surgical outcomes to some extent, without statistically significant differences. The alteration of increased signal intensity was seen postoperatively in 24 patients (23%) and was not correlated with surgical outcome.     

Correlation between operative outcomes of cervical compression myelopathy and mri of the spinal cord

STUDY DESIGN: Magnetic resonance images of cervical compression myelopathy were retrospectively analyzed in comparison with surgical outcomes. OBJECTIVES: To investigate which magnetic resonance findings in patients with cervical compression myelopathy reflect the clinical symptoms and prognosis, and to determine the radiographic and clinical factors that correlate with the prognosis. SUMMARY OF BACKGROUND DATA: Signal intensity changes of the spinal cord on magnetic resonance imaging in chronic cervical myelopathy are thought to be indicative of the prognosis. However, the prognostic significance of signal intensity change remains controversial. METHODS: The participants in this study were 73 patients who underwent cervical expansive laminoplasty for cervical compression myelopathy. Their mean age was 64 years, and the mean postoperative follow-up period was 3.4 years. The pathologic conditions were cervical spondylotic myelopathy in 42 patients and ossification of the posterior longitudinal ligament in 31 patients. Magnetic resonance imaging (spin-echo sequence) was performed in all the patients. The transverse area of the spinal cord at the site of maximal compression was computed, and spinal cord signal intensity changes were evaluated before and after surgery. Three patterns of spinal cord signal intensity changes on T1-weighted sequences/T2-weighted sequences were detected as follows: normal/normal, normal/high-signal intensity changes, and low-signal/high-signal intensity changes. Surgical outcomes were compared among these three groups. The most useful combination of parameters for predicting prognosis was determined using a stepwise regression analysis. RESULTS: The findings showed 2 patients with normal/normal, 67 patients with normal/high-signal, and 4 patients with low-signal/high-signal change patterns before surgery. Regarding postoperative recovery, the preoperative low-signal/high-signal group was significantly inferior to the preoperative normal/high-signal group. There was no significant difference between the transverse area of the spinal cord at the site of maximal compression in the normal/high-signal group and the low-signal/high-signal group. A stepwise regression analysis showed that the best combination of surgical outcome predictors included age (correlation coefficient R = -0.348), preoperative signal pattern, and duration of symptoms (correlation coefficient R = -0.231). CONCLUSIONS: The low-signal intensity changes on T1-weighted sequences indicated a poor prognosis. The authors speculate that high-signal intensity changes on T2 weighted images include a broad spectrum of compressive myelomalacic pathologies and reflect a broad spectrum of spinal cord recuperative potentials. Predictors of surgical outcomes are preoperative signal intensity change pattern of the spinal cord on radiologic evaluations, age at the time of surgery, and chronicity of the disease.     

Obliteration of a tentorial dural arteriovenous fistula causing spinal cord myelopathy using the cranio-orbito zygomatic approach

BACKGROUND: Intracranial dural arteriovenous fistulas account for 10 to 15% of all intracranial arteriovenous malformations. Tentorial dural arteriovenous fistulas with spinal medullary venous drainage causing spinal cord myelopathy are very rare, but have been previously described. We describe a case using a cranio-orbito zygomatic approach with intraoperative angiography for the surgical treatment of a tentorial artery dural arteriovenous fistula causing spinal cord myelopathy. CASE PRESENTATION: A 42-year-old male presented complaining of a 1-year history of incoordination and dizziness and a 2-month history of progressive myelopathy with bowel and bladder incontinence. The patient had magnetic resonance imaging (MRI) performed along with cerebral and spinal angiography that revealed a right tentorial artery dural arteriovenous fistula with spinal medullary venous involvement down to T11. Angiographic embolization was attempted, but selective catheterization was unsuccessful. The patient underwent a cranio-orbito zygomatic approach with obliteration of the dural arteriovenous fistula. An intraoperative angiogram confirmed complete obliteration of the dural arteriovenous fistula. CONCLUSION: Intracranial dural arteriovenous fistulas are a rare cause of spinal cord myelopathy. When a patient presents with suspicion of spinal dural fistula and negative spinal angiography, an intracranial origin should be suspected and a cerebral angiogram performed. Skull base approaches along with intraoperative angiography provide an alternative modality for obliteration of the dural arteriovenous fistula nidus, thereby eliminating the venous congestion and hence the spinal cord ischemia.     

先天性颈椎管狭窄与脊髓型颈椎病影像学表现以及预后的关系

目的 探讨脊髓型颈椎病(cervical spondylotic myelopathy,CSM)患者先天性颈椎管狭窄(cervical spinal stenosis,CSS)与颈椎MRI改变及预后的关系.方法 回顾性分析自2006年11月至2009年11月,采用前路、后路或前后路联合手术治疗的286例CSM患者的病例资料,根据患者是否存在CSS将患者分为两组,在MRI T2加权像上评价脊髓高信号的等级以及脊髓受压程度.记录患者日本骨科学会评分标准(Japanese Orthopaedic Associatio,JOA)评分、病程和体征,包括感觉减退或者消失、Hoffman征、Babinski征、腱反射.结果 在CSM患者中CSS的发生率为33.6%,先天性CSS组的年龄、JOA评分、病程均大于无CSS组,术后临床改善率小于无CSS组.两组之间性别的差异无统计学意义(x2=0.006,P=1.00),两组之间的颈椎MRI T2加权像脊髓高信号发生率的差异有统计学意义(x2=-62.396,P＜0.001),CSS组脊髓高信号的发生率为70.8%,无CSS组脊髓高信号的发生率为22.6%.先天性CSS组脊髓受压程度相对于无CSS组严重,且先天性CSS组患者体征的数目相对较多.应用多元线性回归分析法得出术后改善率与CSS、病程、临床体征的数目和年龄有关(R2=0.565).结论 先天性CSS患者出现CSM时往往脊髓受压程度较重、MRI T2加权像脊髓内高信号出现的概率大,病程长且预后较差.

Abstract：

Objective To investigate the relationship between the cervical MR images and pathological changes, prognosis in patients with cervical spinal stenosis and cervical spondylotic myelopathy. Methods From Nov. 2006 to Nov. 2009, 286 patients with cervical spondylotic myelopathy were included through retrospective analysis. All patients were divided into two groups according to whether there was cervical stenosis, the grade of increased signal intensity (ISI) in spinal cord and the degree of spinal cord compression was evaluate in T2-weighted MR images of midian sagittal slices. JOA scale, duration of disease,Hoffmann sign, Babinski sign, sensory loss or hypoesthesia, and lower-extremity/upper-extremity hyperreflexia were recorded. Results The incidence rate of cervical spinal stenosis was 33.6% in patients with cervical spondylotic myelopathy. The study showed that the age was smaller (P＜ 0.001 ), preoperative JOA score was higher(P=0.0018), duration of disease was longer(P=0.009), and the recovery rate was lower(P＜ 0.001 )in cervical spinal canal narrowing group comparing with control group. There was no significant difference between the two groups in gender (x2=0.006,P=l.00). There was significant difference between two groups in the incidence of ISI in spinal cord through x2 test(x2=62.396,P＜ 0.001 ). Multivariate analysis indicated that the likelihood of the recovery rate of cervical myelopathy decreased with the presence of cervical spinal stenosis, duration of dieaase, number of neurological signs, age (R2=0.565). Conclusion Patients with congenitally narrow cervical spinal canal have to suffer severe spinal cord compression and high incidence of ISI in spinal cord. The duration of disease is long, and prognosis is poor.     

The role of magnetic resonance imaging in the management of traction injuries to the adult brachial plexus

Magnetic resonance imaging (MRI) of the cervical spine and brachial plexus was performed on 26 consecutive patients presenting with traction injuries of the brachial plexus during 1996 and 1997. These included T1 and T2 weighted coronal, sagittal and axial images of the cervical spine and coronal images of the brachial plexus. The results were compared with surgical findings, intraoperative neurophysiology, and subsequent clinical progress. Operations for exploration and repair have been performed in 23 and 26 patients scanned. Evidence of root avulsion was seen in 11 patients in the form of displacement or oedema of the spinal cord, haemorrhage or scarring within the spinal canal, absence of roots in the intervertebral foramena, and meningoceles. Characteristic abnormalities were evident in the MR scans of all cases where exploration confirmed some root avulsions. There were no false positives. MRI underestimated the number of individual roots avulsed; sensitivity was 81%. Post-ganglionic lesions were seen as swelling on T1 images associated with increasing signal on T2 images. It was usually possible to define the level of the injury within the plexus. This study suggests that MR imaging, performed early after traction injury to the brachial plexus, provides useful additional information towards establishing the level of the lesion. It also provides information about injury to the plexus outside the spinal canal.     

A correlation between magnetic resonance imaging and electrophysiological findings in cervical spondylotic myelopathy.

STUDY DESIGN: Correlation between compressed spinal cords on magnetic resonance imaging (MRI) and electrophysiological findings in cervical spondylotic myelopathy patients. OBJECTIVE: To clarify the correlation between spinal-cord-evoked potentials and MRI measurements of compressed spinal cords in patients with cervical spondylotic myelopathy. SUMMARY OF BACKGROUND DATA: Compression of the spinal cord does not always cause clinical symptoms and it is difficult to infer the degree of dysfunction of the spinal cord from MRI findings. METHODS: Seventeen patients with cervical spondylotic myelopathy were examined with MRI and spinal-cord-evoked potentials before surgery. Using abnormality in spinal-cord-evoked potentials as indicators of spinal cord morphology, spinal-cord transverse area and compression ratios (central and 1/4-lateral) were measured on T1-weighted axial imaging. The correlations between these dimensions and electrophysiological findings were investigated. RESULTS: The mean preoperative transverse area of the spinal cord was 47.13 mm2.The mean preoperative central compression ratio of the spinal cord was 34.4%. The mean preoperative 1/4-lateral compression ratio of the spinal cord was 27.5%. A correlation (Spearman r=0.65, P < 0.01) was observed between the 1/4-lateral compression ratio of the spinal cord and the amplitude ratio of spinal-cord-evoked potentials after electric stimulation of the brain (Br(E)-SCEPs). CONCLUSIONS: The preoperative 1/4-lateral compression ratio of the spinal cord was found to reflect the degree of dysfunction of the corticospinal tracts.     

Diagnosis and surgical treatment of spinal hemangioblastoma

Spinal hemangioblastoma is a rare tumor. Its incidence varies from 1.6 to 2.1% of primary spinal cord tumors. In this report, the authors described MRI (magnetic resonance imaging) of spinal hemangioblastoma and its surgical results. [MATERIALS AND METHODS] This series included 10 spinal hemangioblastomas studied with CT or MRI. There were 8 men and 2 women. The age ranged from 21 to 68 years, with a mean age of 45 years. 6 patients were preoperatively and postoperatively studied with a resistive 0.15 T system (Toshiba MRT 15A) or a superconductive 1.5 T system (GE Signa or Siemens Magnetom). The lesions were single in 8 out of 10 patients and multiple in 2. 10 spinal hemangioblastomas were located in intramedullary space and 2 in both intramedullary and extramedullary space. 8 out of 10 patients (80%) were associated with cyst. [RESULTS] (1) MRI In T1-weighted MR images after administration of Gd-DTPA, the solid component of the tumor enhanced brilliantly. The enhanced lesions contained serpiginous areas of signal void, reflecting vascular structures in 5 out of 6 cases. The intrinsic spinal cord signal was heterogenous with low intensity areas representing the associated cyst. The cyst appeared either isointensive to cerebrospinal fluid (CSF) or hyperintense relative to CSF and slightly hypointense relative to the spinal cord. The precise delineation of the tumor was impossible without enhancement. Noncontrast T1-weighted MR images displayed diffuse widening of the spinal cord. On T2-weighted MR images, all regions of the spinal cord enlargement increased in signal. (2) Postoperative results All 10 cases of spinal hemangioblastomas were totally removed with good postoperative results and the associated cysts were drained. The postoperative MRI showed the disappearance of the tumor and significant reduction in the size of the cyst. [CONCLUSION] (1) Gd-DTPA enhanced MRI was useful in defining and outlining the solid component of spinal hemangioblastoma. (2) The complete removal of the tumor with only drainage of the cyst was possible with good postoperative results.     

Increased signal intensity of the spinal cord on magnetic resonance images in cervical compressive myelopathy. Does it predict the outcome of conservative treatment?

STUDY DESIGN: Correlation between a lesion of the spinal cord that elicits increased signal intensity (ISI) on magnetic resonance images (MRIs) and the outcome of conservative treatment for cervical compressive myelopathy was retrospectively investigated. OBJECTIVE: To investigate whether ISI could predict the outcome of conservative treatment for cervical compressive myelopathy. SUMMARY OF BACKGROUND DATA: It is unknown whether ISI is related to the outcome of conservative treatment for cervical compressive myelopathy. METHODS: Fifty-two patients with mild cervical myelopathy underwent conservative treatment with a cervical brace. The compressive lesions were spondylosis in 29 patients, disc herniation in 12, and an ossification of the longitudinal ligament in 11. They also underwent MRI (1.5 T), and ISI was evaluated on T2-weighted sagittal and axial images. The ISI areas were classified as focal or multisegmental. Thirty-nine patients underwent follow-up MRI after a mean interval of 2 years, 4 months. The transverse area of the spinal cord was also measured on T2-weighted axial images. The outcome of conservative treatment was assessed using the Japanese Orthopedic Association Score (JOA score). Patients showing either an improvement in the JOA score or with a JOA score of 15 or more were considered to have a satisfactory outcome. RESULTS: The average JOA score was 14.0 +/- 1.4 (range, 10-16) before conservative treatment and 14.4 +/- 1.9 (range, 10-17) at follow-up. The average gain in the JOA score was 0.4 points +/- 1.9 (range, -5 to +6). The outcome was satisfactory in 36 patients (69%). An area of ISI was observed in 34 patients (65%) before treatment (24 focal and 10 multisegmental). A satisfactory outcome was obtained in 78% of the patients without ISI, in 63% of those with focal ISI, and in 70% of those with multisegmental ISI. No statistically significant difference was seen among these three groups in the percentages of patients with satisfactory outcome, JOA scores before and after treatment or transverse spinal cord area. Of the 39 patients who were re-examined by MRI, 28 showed an area of ISI. The ISI regressed in five patients (18%). Satisfactory outcome was obtained in all 5 patients with regression of ISI, in 16 (70%) of the 23 patients without regression of ISI, and in 10 (91%) of the 11 patients without ISI apparent on the the first images (difference, not significant). CONCLUSIONS: Increased signal intensity was not related to a poor outcome of conservative treatment or severity of myelopathy in the patients with mild cervical myelopathy.     

The effects of MRI signal intensity changes and clinical manifestations on prognosis after surgical intervention for cervical spondylotic myelopathy

Objective: To investigate whether the magnetic resonance (MR) T2 image signal intensity ratio and clinical manifestations can predict the prognosis in patients with cervical spondylotic myelopathy (CSM). Methods: A total of 73 patients treated with anterior, posterior, or posterior‐anterior combined surgery for compressive cervical myelopathy were enrolled retrospectively in this study. 1.5 T magnetic resonance imaging (MRI) was performed on all patients before surgery. T2‐weighted images (T2WI) of sagittal signal intensity were obtained of the cervical spinal cord, and the regions of interest (ROI) were taken by 0.05 cm². MR T2WI of sagittal normal cord signal at the C7‐T1 disc level were also obtained, and the ROI were taken by 0.3 cm². Signal value was measured by computer and the signal ratio between regions 0.05 cm² and 0.3 cm² calculated. Where no intramedullary high signal intensity was noted on MR T2WI, the ROI were taken by 0.05 cm² of the region of most severe spinal cord compression. The 73 patients were divided into three groups by hierarchical clustering analysis with signal intensity ratio (group 1: low signal intensity ratio; group 2: middle signal intensity ratio; group 3: high signal intensity ratio). Statistical analyses were performed with SPSS 11.0. Results: There were significant differences between the three groups according to the recovery rate (P < 0.001), age (P= 0.003), duration of disease (P= 0.001), Babinski sign (P < 0.001), pre‐ and postoperative Japanese Orthopaedic Association (JOA) score (P= 0.006). With increases in both signal intensity ratio grade and age, the recovery rate and pre‐ and postoperative JOA scores gradually decreased, and the incidence of Babinski sign increased. There was no significant difference in sex among the three groups (P= 0.387). Multiple comparison tests further supported the above‐mentioned results. Conclusion: Patients with light or no intramedullary signal changes on T2WI had a good surgical outcome. However, increase of signal intensity ratio and occurrence of the pyramidal sign were associated with a poor prognosis after surgery.