两种不同术式治疗合并颈椎后纵韧带骨化的重度脊髓型颈椎病疗效分析

目的探讨前路、后-前联合入路两种不同术式治疗合并颈椎后纵韧带骨化(Ossificationof posterior longitudinal ligament,OPLL)的重度脊髓型颈椎病的适应证及临床疗效。方法对38例合并颈椎OPLL的重度脊髓型颈椎病患者分别行颈椎前路手术(A组,22例)和后-前联合入路手术(B组,16例)。比较两组患者椎管狭窄率、骨化节段及脊髓压迫率的差异,并根据术前及术后随访时的JOA评分,评价两组患者的神经功能恢复情况。结果所有病例随访12～30个月,平均20个月,术中未出现脊髓、椎动脉损伤等严重并发症,两组脊髓功能均获不同程度改善。A组JOA评分从术前平均(7.9+2.1)分提高至术后1年平均(13.1+1.7)分,平均改善率为(65.9+5.2)%;B组JOA评分从术前平均(6.8+1.6)分提高至术后1年平均(13.9+0.9)分,平均改善率为(69.8+4.5)%,对比两组患者疗效无统计学差异(P>0.05)。结论采用前路或后-前联合入路治疗合并颈椎OPLL的重度脊髓型颈椎病,均取得彻底的椎管减压和良好的临床疗效,根据脊髓受压程度、影像学资料、骨化范围及患者全身情况合理选择恰当的手术入路是手术成功的关键。     

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).     

Successful treatment of a group of spinal cord arteriovenous malformations by interruption of dural fistula

As demonstrated by selective spinal cord arteriography, over 80% of spinal cord arteriovenous malformations (AVM's) occupy a predominantly extramedullary position. Current therapy frequently requires surgical stripping of the long dorsal intradural vessel(s) from the underlying spinal cord over many cord segments. The authors report six patients with a dural arteriovenous fistula fed by a cluster of abnormal epidural arteries. These vessels, which surrounded and were embedded into the dural covering of a thoracic nerve root, drained into a long sinuous intrathecal paramedullary vein(s). The angiographic and surgical appearance of the intradural component of these lesions was identical to that of lesions previously classified as Type I AVM's of the spinal cord. All patients had symptoms and signs of myelopathy. In five patients, surgery was limited to coagulation and excision of the extradural vessels and division of the intradural arterialized vein. Progressive improvement began within days following surgery. No residual abnormality was demonstrated by postoperative selective spinal cord arteriography, which was performed in all five patients. The findings support those of Kendall and Logue, that surgery restricted to elimination of the arteriovenous fistula at the intervertebral foramen is curative, and that more extensive surgery is unnecessary for this subgroup of AVM's of the spinal cord. These lesions comprise a sizable percent of all spinal AVM's. Resolution of myelopathy in these patients supports the hypothesis that venous hypertension causes chronic progressive myelopathy.     

Potential usefulness of 18F-2-fluoro-deoxy-D-glucose positron emission tomography in cervical compressive myelopathy.

STUDY DESIGN: This case study describes the usefulness of high-resolution 18F-2-fluoro-deoxy-D-glucose (18FDG)-positron emission tomography (PET) for metabolic neuroimaging of the cervical spinal cord in patients with compressive myelopathy. OBJECTIVE: To examine whether 18FDG-PET imaging could visualize deterioration of cervical spinal cord function associated with a variable degree of compression and to determine its potential usefulness during assessment of myelopathy. SUMMARY OF BACKGROUND DATA: A few studies have described the use of 18FDG-PET imaging in cervical cord diseases, but visualization of the cervical spinal cord before and after surgical decompression for compressive myelopathy has not been reported. The potential usefulness of 18FDG-PET imaging for assessment of the function of compressed cervical cord has not been discussed previously. METHODS: An 18FDG-PET scan was performed before and after surgery in seven patients with cervical compressive myelopathy. The correlation between the metabolic rate of glucose of the cervical spinal cord and neurologic scores was evaluated. The metabolic rate of glucose in different vertebral levels was also measured. RESULTS: Preoperative metabolic rate of glucose was high in two patients but low in the other five. At the time of the second postoperative examination, metabolic rate of glucose was higher in six of the seven patients, and the increase was associated with neurologic improvement. Use of 18FDG was not related to changes in signal intensities on T2-weighted magnetic resonance images. The metabolic rate of glucose decreased at the affected vertebral level in four patients, increased in two, and did not change in one, relative to the unaffected levels. CONCLUSIONS: High-resolution 18FDG-PET neuroimaging may provide clinically useful qualitative and quantitative estimation of impaired metabolic activity of the compromised cervical spinal cord in compressive myelopathy. 18FDG-PET images may also offer additional information related to neuronal dysfunction induced by mechanical compression.     

Prognostic value of changes in spinal cord signal intensity on magnetic resonance imaging in patients with cervical compressive myelopathy

Background contextSignal intensity on preoperative cervical magnetic resonance imaging (MRI) of the spinal cord has been shown to be a potential predictor of outcome of surgery for cervical compressive myelopathy. However, the prognostic value of such signal remains controversial. One reason for the controversy is the lack of proper quantitative methods to assess MRI signal intensity.PurposeTo quantify signal intensity and to correlate intramedullary signal changes on MRI T1- and T2-weighted images (WIs) with clinical outcome and prognosis.Study designRetrospective case study.Patient samplePatients (n=148; cervical spondylotic myelopathy, n=102 and ossified posterior longitudinal ligament, n=46) who underwent surgery for cervical compressive myelopathy and had high signal intensity change on sagittal T2-WI MRI before surgery between 2006 and 2010.Outcome measureNeurologic assessment was conducted with the Japanese Orthopedic Association (JOA) scoring system for cervical myelopathy. The rate of neurologic improvement was calculated with the use of preoperative and postoperative JOA scores.MethodsQuantitative analysis of MRI signal on both T1- and T2-WIs via use of the signal intensity ratio (SIR; signal intensity of lesion relative to that at C7-T1 disc level) was performed. Correlations between SIR on T1- and T2-WIs and preoperative JOA score, JOA improvement rate, disease duration, and MRI morphologic classification (cystic or diffuse type) were analyzed. Multivariate regression analysis for JOA improvement rate was also analyzed. In a substudy, 25 patients underwent follow-up MRI starting from 6 months after surgery to analyze the relationship between changes in SIR on follow-up MRI and clinical outcome.ResultsSIR on T1-WIs, but not SIR on T2-WIs, correlated with postoperative neurologic improvement. The disease duration correlated negatively with SIR on T1-WIs and JOA improvement rate but not with SIR on T2-WIs. SIR on T2-WIs of “cystic type” was significantly greater than of “diffuse type,” but SIR on T1-WI and JOA improvement rate were not different in the two types. Stepwise multivariate regression analysis indicated that SIR on T1-WIs and long disease duration were significant predictors of postoperative neurologic outcome. SIR on follow-up T1-WI and changes in SIR on T1-WI after surgery correlated positively with postoperative improvement rate. SIR on follow-up T2-WI and changes on T2-WI correlated negatively with postoperative neurologic improvement.ConclusionsOur results suggest that low intensity signal on preoperative T1-WIs but not T2-WIs correlated with poor postoperative neurologic outcome. Furthermore, decreased signal intensity on postoperative T1-WIs and increased signal intensity on postoperative T2-WIs are predictors of poor neurologic outcome.     

Perfusion-weighted magnetic resonance imaging of the spinal cord in cervical spondylotic myelopathy

Principles of echo shifting with a train of observations was used to perform magnetic susceptibility-weighted magnetic resonance imaging with bolus-tracking in 14 patients with spondylotic myelopathy to assess changes in perfusion parameters of the spinal cord before and after decompression surgery for cervical spondylotic myelopathy. The mean transit time (MTT), bolus arrival time (T0), and time to peak (TTP) were obtained from regions of interest (ROIs) and assessed as the ratio between the spinal cord and the pons (MTT index = MTT(ROI)/MTT(pons), T0 index = T0(ROI)/T0(pons), TTP index = TTP(ROI)/TTP(pons)). The patients were divided into two groups according to percentage improvement on the Neurosurgical Cervical Spine Scale. The MTT index in patients with good recovery (> or =50%) was significantly reduced. The T0 index and TTP index showed no significant change in both groups. Reduction of MTT index may indicate improved perfusion of the spinal cord following surgery for cervical spondylotic myelopathy.     

Quantitative analysis of cerebrospinal fluid flow in patients with cervical spondylosis using cine phase-contrast magnetic resonance imaging

OBJECTIVE: To investigate changes in the cerebrospinal fluid flow in patients with cervical spondylosis using cine phase-contrast magnetic resonance (MR) imaging. METHODS: The participants included 44 healthy volunteers, 11 asymptomatic patients with evidence of degenerative changes of the cervical spine revealed by MR imaging but no neurological symptoms referable to those abnormalities, and 23 symptomatic patients with myelopathy who underwent surgery. Cervical spondylotic myelopathy was evaluated using the Japanese Orthopedic Association scores, and the percentage reduction of the transverse cord area at the level of maximum cord compression was measured on T1-weighted magnetic resonance images. A cine phase-contrast MR pulse sequence with peripheral gating was used to measure the cerebrospinal fluid flow direction and velocity in the ventral subarachnoid spaces at the C1 and T1 levels. RESULTS: The velocity waveforms produced by plotting flow velocity at 16 intervals during one cardiac cycle significantly differed among the healthy volunteers, asymptomatic patients, and preoperative symptomatic patients. However, velocity waveforms did not differ between the healthy volunteers and the postoperative patients at the C1 level. Decreases of flow velocity were significantly correlated with the severity of myelopathy and the percentage reduction of cord area. Patients with severe myelopathy (Japanese Orthopedic Association score of 0-9 points) or greater than 30% reduction of cord area showed significantly decreased flow velocity compared with those with mild myelopathy (Japanese Orthopedic Association score of 10-17 points) or less than 30% reduction of cord area. Changes in flow velocity were not correlated with multiplicity of the lesion or the level of maximum cord compression. Postoperative improvement of flow velocity was not correlated with neurological recovery. CONCLUSION: Cine phase-contrast MR imaging allows quantitative and noninvasive assessment of changes in cerebrospinal fluid flow in patients with cervical spondylosis.     

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。     

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.     

扩散张量成像预测颈椎后路椎管扩大成形术后脊髓功能波动的价值

背景:颈椎后路椎管扩大成形术后脊髓功能波动会影响患者的远期疗效,但关于如何预测术后出现脊髓功能波动的研究较少。目的:探讨扩散张量成像(DTI)预测颈椎后路椎管扩大成形术后脊髓功能波动的价值。方法:前瞻性选择2017年1~12月收治的行颈椎后路椎管扩大成形术的颈椎退行性疾病患者。术前采集患者日本骨科协会(JOA)评分及脊髓压迫最重节段(LMC)与C2椎体后方正常脊髓的DTI参数;术后3个月、1年随访采集患者JOA评分并进行常规MRI扫描。比较术后脊髓功能波动组与无波动组患者术前DTI参数差异,并绘制术前DTI参数预测术后脊髓功能波动的受试者操作特征(ROC)曲线。结果:本研究最终纳入65例患者。术后11例患者(16.9%)发生脊髓功能波动(术后脊髓功能波动组),而54例患者(83.1%)未发生(术后脊髓功能无波动组)。术后脊髓功能波动组患者术前C2椎体后方正常脊髓的轴向扩散系数(AD)值低于无波动组患者,且差异有统计学意义(P<0.05)。ROC曲线显示,C2椎体后方正常脊髓的AD值预测术后脊髓功能波动的阈值为1.4×10^-3 mm^2/s,敏感度为90.0%,特异度为56.9%。结论:AD值能够在术前提示颈椎后路椎管扩大成形术后患者脊髓功能波动。     

Does increased signal intensity of the spinal cord on MR images due to cervical myelopathy predict prognosis?

We examined whether or not high signal intensity change on magnetic resonance imaging of the spinal cord of patients with cervical myelopathy is related to the clinical symptoms and prognosis. Twenty-five patients with cervical myelopathy were treated by decompressive surgery which involved laminoplasty or decompressive anterior interbody fusion. The pathological conditions were cervical disc herniation (n = 8), ossification of the posterior longitudinal ligament in the cervical spine (n = 7), and cervical spondylotic myelopathy (n = 10). The spinal cord compression and the intramedullary signal intensity at the site of maximum compression were evaluated pre- and postoperatively using T1- and T2-weighted images. There was no significant relationship between spinal cord compressive change and clinical symptoms. Patients in whom the high signal change of the spinal cord on T2-weighted sequence recovered after decompressive surgery had better recovery from clinical symptoms, but a statistical significance was not found. We suggest that signal changes on T2-weighted images may reflect pathological changes but cannot be used to predict prognosis at present.     

Surgery for cervical spinal cord compression in patients with multiple sclerosis

OBJECTIVE: The goal of this study was to investigate the clinical and paraclinical features, treatment, and outcomes of patients with multiple sclerosis (MS) and coexisting spinal cord compression secondary to either cervical spondylosis or cervical disc disease. Patients with MS commonly experience neurological disabilities that present as myelopathy associated with bladder dysfunction. For some patients with MS, however, this neurological deterioration may result from coexisting spinal cord compression attributable to either spondylosis or a herniated disc. Overlapping symptoms of the two conditions do not allow clear clinical determination of the underlying cause of worsening. METHODS: Patients with MS who underwent cervical decompression surgery were selected. Medical records were retrospectively reviewed, to collect data on their pre- and postoperative clinical courses. RESULTS: Nine women and five men with definite MS were selected for cervical decompression surgery to treat neurological deterioration considered to be at least partially attributable to spinal cord compression. The most common symptoms were progressive myelopathy (n = 13), neck pain (n = 11), and cervical radiculopathy (n = 10). Bladder dysfunction was notably absent among these patients with MS with moderate disabilities. Surgical intervention was frequently delayed because the neurological deterioration was initially thought to be attributable to MS. The majority of patients experienced either improvement or stabilization of their preoperative symptoms in the immediate postoperative period; three subjects (21%) maintained this improvement after a mean follow-up period of 3.8 years. No MS relapses, permanent neurological worsening, or serious complications resulting from surgery or general anesthesia were noted. CONCLUSION: Carefully selected patients with MS and cervical spinal cord compression secondary to either spondylosis or disc disease may benefit from surgical decompression, with minimal associated morbidity. Clinical features (especially neck pain and cervical radiculopathy) and magnetic resonance imaging may assist clinicians in differentiating between the two conditions and may guide appropriate treatment without undue delay.     

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.     

Posterior stabilization of the cervical spine in rheumatoid arthritis: clinical results and magnetic resonance imaging correlation

Thirteen patients with atlantoaxial dislocation(s) had posterior stabilization and were evaluated clinically with magnetic resonance (MR) imaging and conventional radiography both pre- and postoperatively. Cases with anterior instability had large periodontoid granulomatous pannus formation, but this was lacking in cases with fixed cranial settling. The pannus caused cord compression in four cases and occupied the entire anterior subarachnoid space in four other cases. After stabilization, the granuloma decreased in size in all patients and in four cases it vanished completely. Major signs of myelopathy corresponded to cord compression at MR imaging. Minor possible signs of neural deficit were found in seven cases and their importance was not clearly understood before surgery, but because all preoperative symptoms disappeared, it was necessary to check for even obscure signs as early warnings of a threatening myelopathy.     

Investigation of motor dominant C5 paralysis after laminoplasty from the results of evoked spinal cord responses

BACKGROUND: Postoperative motor dominant C5 paralysis was known as one of several complications after laminoplasty. Several theories have been proposed for postoperative segmental paralysis after laminoplasty, but its etiology remains unclear. OBJECTIVE: To investigate the possible mechanism for postoperative motor dominant C5 paralysis from intraoperative electrophysiological studies using evoked spinal cord potentials (ESCPs). METHODS: A total of 66 patients who had undergone laminoplasty due to compressive cervical myelopathy were studied retrospectively. In all patients, the symptomatic intervertebral levels of cervical myelopathy were identified by several types of the ESCPs. Motor dominant C5 paralysis was determined as at least 1 level down compared with pre-operative shoulder abduction according to the manual muscle testing. RESULTS: Five patients (7.6%) showed postoperative motor dominant C5 paralysis. C5 paralysis occurred from 1 to 3 days after surgery and compromised unilaterally in all 5 patients. The causes of cervical myelopathy were cervical spondylosis in 3 patients and ossification of the posterior longitudinal ligament in 2 patients. One patient with severe impairment (2 in manual muscle-testing [MMT] scale) did not show clinical recovery. The other 4 patients recovered to 4 or 5 on the MMT score from 3 to 6 months after the onset. Based on the findings of ESCPs, the C4-5 level was affected by cervical myelopathy in all 5 patients with postoperative motor dominant C5 paralysis (C4-5 level in 3 patients, both C4-5 and C5-6 levels in 2 patients). A high signal intensity area on T2-weighted magnetic resonance imaging (MRI) was observed in all patients who showed apparent motor dominant C5 paralysis in this study. CONCLUSIONS: Cervical myelopathy at the C4-5 level is a potential risk for motor dominant C5 paralysis. Although it is merely a speculation, when C5 radiculopathy occurs after laminoplasty, C5 paralysis becomes clinically apparent because the deltoid muscle gets predominantly innervated by C5 root due to intramedullary spinal cord damage on the C6 segment in C4-5 myelopathy before surgery. It may represent the high signal intensity area on T2-weighted MRI at the C4-5 level.     

Extensor musculature of the cervical spine after laminoplasty: morphologic evaluation by coronal view of the magnetic resonance image

STUDY DESIGN: A radiographic study in 22 patients using magnetic resonance imaging was conducted. OBJECTIVE: To describe the relation between postoperative cervical alignment and morphologic evaluation of the cervical extensor musculature, especially semispinalis cervics in laminoplasty. SUMMARY OF BACKGROUND DATA: Cervical laminoplasty has been widely accepted as a treatment for cervical myelopathy. Posterior procedures, however, involve the extensor musculature of the cervical spine. METHODS: In this study, 22 patients who underwent laminoplasty for repair of the extensor musculature were reviewed prospectively. The semispinalis cervics was evaluated by coronal view of the magnetic resonance image 1 month, 12 months, and 24 months after surgery. Cervical alignment at last follow-up assessment was compared with preoperative alignment using the lateral view of cervical radiographs. RESULTS: In 18 patients (82%), morphologic repair of semispinalis cervics had been maintained (Group A), but in 4 patients (18%), but it had not been maintained at the last follow-up assessment (Group B). Cervical alignment in Group A had been maintained, but maximum loss of cervical lordosis occurred in Group B. Moreover, Group B consisted of elderly women. CONCLUSIONS: The findings from this magnetic resonance imaging study suggest that the degree of semispinalis cervics repair affects postoperative cervical alignment, and significant loss of cervical lordosis tends to occur in elderly women who undergo laminoplasty.     

Neurological recovery in patients of old healed tubercular rigid kyphosis with myelopathy treated with transpedicular decancellation osteotomy

Purpose

The purpose of the study was to find out if transpedicular decancellation osteotomy (TDO) is recommendable for neurological recovery in patients with myelopathy due to tubercular rigid kyphosis. We have analyzed the pattern of recovery seen after the surgery and also made an effort to correlate the neurological recovery with preoperative clinical and radiological features.

Methods

The clinical parameters used were (1) ASIA impairment scale for motor and sensory function, (2) sphincter dysfunction score, (3) time duration from the onset of myelopathy till the date of surgery, and (4) SRS 30 outcomes questionnaire. Radiological parameters used were (1) Cobb’s angle in standing/sitting radiographs, (2) levels of gibbus, (3) cord changes in sagittal T2 MRI images, and (4) percentage of cord compression. Assessment was done preoperatively and at 1 month, 3 months, 6 months, 1 year and at 2 years postoperatively.

Results

Seventeen patients were included. The follow-up period was 2 years. We had one patient in ASIA A, nine patients in ASIA C and seven patients in ASIA D. Four patients with ASIA C presented with mild sphincter disturbance (score 2) and one presented with severe disturbance (score 1). The ASIA A patient had complete retention (score 0). The ASIA impairment scale improved after surgery, with maximum improvement at 3 months and improvement continuing up to 6 months. 16 (94 %) patients had improvement in lower limb function and 5 (83 %) patients had improvement of sphincter function. 94 % patients had neurological recovery after the operation. The neurological recovery reached a plateau at 6 months with no significant improvement in the further follow-up. Preoperative MRI changes, cord compression and duration from onset of myelopathy to day of surgery were not predictive of the final neurological outcome after surgery.

Conclusion

TDO gives good results in delayed onset neurological deficits in caries spine with rigid kyphosis. At least, one grade improvement in the neurological status of patients with ASIA C and ASIA D can be expected. Maximum improvement in the neurology is seen in the first 3 months and up to 6 months from the date of surgery, without much improvement thereafter. Level of evidence Level IV.     

A radical procedure of circumferential spinal cord decompression through a modified posterior approach for thoracic myelopathy caused by severely impinging anterior ossification

Background contextThoracic myelopathy caused by an anterior, massive ossified plaque is often progressive and responds poorly to conservative treatment. Direct removal of the compressing ossification is the optimal procedure for a spinal cord that is severely impinged anteriorly. However, both anterior and posterior decompressive manipulations have caused catastrophic iatrogenic spinal cord injuries. A comprehensive treatment method for severe thoracic myelopathy that enables a sufficient and safe decompression of the spinal cord is needed.PurposeThe purpose of this study is to demonstrate the efficacy, safety, and results of a one-stage circumferential decompressive procedure using a modified posterior approach in patients with severe thoracic myelopathy resulting from anterior spinal compression.Study designA modified procedure of circumferential spinal cord decompression for thoracic myelopathy is described. A retrospective study was conducted to investigate the clinical outcomes of 23 sequentially treated patients.Patient sampleTwenty-three patients were treated sequentially with a modified procedure for circumferential spinal cord decompression for thoracic myelopathy.Outcome measuresOutcomes were assessed using the Japanese Orthopedic Association (JOA) score, modified Frankel classification, Hirabayashi recovery rate, and a general assessment of complications.MethodsTwenty-three patients with thoracic myelopathy caused by a massive, anterior ossified structure were treated with an extensive posterior laminectomy, anterior removal of the ossification, and interbody fusion with kyphosis-reversing stabilization through a modified posterolateral approach. The neurologic outcomes are evaluated according to the JOA and the modified Frankel classification before surgery, 2 weeks after surgery, 1 year after surgery, and at the final follow-up visit. The surgical outcomes are also described using the Hirabayashi recovery rate. Radiographs, computed tomography (CT), and magnetic resonance imaging were performed before and after surgery. A postoperative CT scan was obtained to determine the efficacy of the decompression. Operative time, intraoperative blood loss, and complications were reviewed from the medical records. In addition, a 48-year-old man who presented with severe thoracic myelopathy resulting from anterior impingement with multiple osteophytes is described as an illustrative patient.ResultsThe sites of ossification in this series were distributed widely, from T4–T12. The anterior ossified plaques of all patients were resected completely. Five patients who had intraoperative evidence of dural ossification required resection of the ossified dura matter. The average operating time was 276 minutes. Mean intraoperative blood loss was 1,350 mL. The postoperative follow-up ranged from 2.5 to 6 years, with an average of 4.6 years. The average preoperative JOA score was 4.3±1.5 points, and it improved to 6.1±1.9 points 2 weeks postoperatively, to 8.1±1.8 points 1 year postoperatively, and to 8.5±1.9 points at the most recent follow-up. The overall Hirabayashi recovery rate at the final examination averaged 63.6±22.4%. Eight patients were graded as excellent, 10 as good, 4 as fair, and 1 as unchanged. No patient was graded as deteriorated. The paralysis improved by at least 1 grade in 22 patients (95.7%). Transient deterioration of thoracic myelopathy occurred immediately after surgery in three patients (13%). Cerebrospinal fluid leakage occurred in six patients (26.1%). One patient sustained severe bilateral groin pain, three had unilateral intercostal neuralgia, and pleura tear occurred in one patient.ConclusionOne-stage posterior decompression, anterior extirpation of the ossification, and interbody fusion with instrumentation via a modified posterior approach is a safe and effective treatment for severe thoracic myelopathy resulting from prominent anterior impingement. This procedure is technically demanding, and the indications are limited to thoracic myelopathy caused by severe anterior impingement of various etiologies from T4–T12.     

Monitoring of somatosensory evoked potentials during surgery for middle cerebral artery aneurysms

Somatosensory evoked potentials (SEPs) were monitored during 53 procedures for aneurysms of the middle cerebral artery (MCA). "Significant" changes were reported to the surgeon, who took corrective action when possible. Changes in the SEPs were categorized as follows: Type I, no change; Type II, significant change with complete return to baseline; Type III, significant change with incomplete return to baseline; Type IV, complete loss with no return; and Type V, no response at baseline. Only 1 of 37 patients with a Type I SEP had a new neurological deficit, and this was a patient who could not be examined for several days after surgery because he was in a pentobarbital coma. All 4 patients with Type III and IV changes had new postoperative neurological deficits. Perhaps of greater importance, 4 of 5 patients with Type II changes had no new deficit. These patients all had changes in SEPs that were completely reversible by clip adjustment (2), prompt removal of temporary clips (1), and inducing hypertension after aneurysm trapping (1). These cases may, therefore, represent instances in which SEP monitoring allowed the clinicians to prevent a neurological deficit. The MCA supplies the area of the somatosensory cortex that controls the hand. Median nerve SEPs are, therefore, a theoretically ideal monitor during surgery for MCA aneurysms. This study suggests that the results of MCA aneurysm surgery may be accurately predicted and improved with SEP monitoring.     

Open-door laminoplasty with suture anchor fixation for cervical myelopathy in ossification of the posterior longitudinal ligament

Expansive laminoplasty was developed to achieve posterior spinal cord decompression while preserving cervical spine stability. In the classic Hirabayashi procedure, the lamina door is tethered open by sutures between the spinous process and facet capsule or paravertebral muscle. The authors present a modified technique, which enhances secure fixation and prevents restenosis owing to hinge closure. Twenty-seven patients (7 females, 20 males) with cervical myelopathy secondary to ossification of the posterior longitudinal ligament were enrolled. Each patient underwent unilateral open-door laminoplasty with suture anchor fixation. Tying and fixation of the sutures onto the holed lateral mass screws was used instead of the conventional method. Radiography, magnetic resonance imaging, and computed tomography scanning were used for imaging studies. The Nurick score was used to assess myelopathy severity, whereas the Japanese Orthopedic Association score was adopted to compare clinical outcome before and after surgery. Mean follow-up period was 38 months (range, 18 to 60). Ten patients had 5 levels of decompression (C3-7), and 17 patients had 4 (C3-6, 12 patients; C4-7, 5 patients). All patients experienced functional improvement of at least 1 Nurick score after surgery. The Japanese Orthopedic Association score increased significantly from 7.5+/-3.2 before surgery to 13.2+/-1.6 at final follow-up. Postoperative radiography and computed tomography scan demonstrated significantly increased sagittal diameter and canal expansion. No neurologic deterioration owing to hinge reclosure or major surgery-related complications were observed. In conclusion, unilateral open-door laminoplasty with suture anchor fixation effectively maintains expansion of the spinal canal and resists closure while preserving alignment and stability. This modified technique has a low complication rate and provides marked functional improvement in patients with cervical myelopathy owing to ossification of the posterior longitudinal ligament.