Long-term results of double-door laminoplasty for cervical stenotic myelopathy

STUDY DESIGN: A retrospective study of the long-term results from double-door laminoplasty (Kurokawa's method) for patients with myelopathy caused by ossification of the posterior longitudinal ligament and cervical spondylosis was performed. OBJECTIVE: To know whether the short-term results from double-door laminoplasty were maintained over a 10-year period and, if not, the cause of late deterioration. SUMMARY OF BACKGROUND DATA: There are few long-term follow-up studies on the outcome of laminoplasty for cervical stenotic myelopathy. METHODS: In this study, 35 patients with cervical myelopathy caused by ossification of the posterior longitudinal ligament in the cervical spine and 25 patients with cervical spondylotic myelopathy, including 5 patients with athetoid cerebral palsy, underwent double-door laminoplasty from 1980 through 1988 and were followed over the next 10 years. The average follow-up period was 153 months (range, 120-200 months) in patients with ossification of the posterior longitudinal ligament and 156 months (range, 121-218 months) in patients with cervical spondylotic myelopathy. Neurologic deficits before and after surgery were assessed using a scoring system proposed by the Japanese Orthopedic Association (JOA score). Patients who showed late deterioration received further examination including computed tomography scan and magnetic resonance imaging of the cervical spine. RESULTS: In 32 of the patients with ossification of the posterior longitudinal ligament and 23 of the patients with cervical spondylotic myelopathy, myelopathy improved after surgery. The improvement of Japanese Orthopedic Association scores was maintained up to the final follow-up assessment in 26 of the patients with ossification of the posterior longitudinal ligament and 21 of the patients with cervical spondylotic myelopathy. Late neurologic deterioration occurred in 10 of the patients with ossification of the posterior longitudinal ligament an average of 8 years after surgery, and in 4 of the patients with cervical spondylotic myelopathy, including the 3 patients with athetoid cerebral palsy, an average of 11 years after surgery. The main causes of deterioration in patients with ossification of the posterior longitudinal ligament were a minor trauma in patients with residual cervical cord compression caused by ossification of the posterior longitudinal ligament and thoracic myelopathy resulting from ossification of the yellow ligament in the thoracic spine. CONCLUSIONS: The short-term results of laminoplasty for cervical stenotic myelopathy were maintained over 10years in 78% of the patients with ossification of the posterior longitudinal ligament, and in most of the patients with cervical spondylotic myelopathy, except those with athetoid cerebral palsy. Double-door laminoplasty is a reliable procedure for individuals with cervical stenotic myelopathy.     

重症脊髓型颈椎病前、后路联合手术治疗次序的选择

目的：探讨前、后路联合手术治疗重症脊髓型颈椎病手术次序选择的原则.方法：回顾性分析45例重症脊髓型颈椎病患者,男27例,女18例,先行颈椎前路减压再行后路椎管扩大成形手术19例（A组）,先行颈椎后路椎管扩大成形再行前路减压融合手术26例（B组）.术前、术后均采用JOA评分法进行评分,根据JOA评分改善率评价两组治疗效果的优良率.结果：术中A组1例因前路手术使椎管前方骨化组织进一步挤压脊髓组织致患者截瘫;2例因前路手术致压物切除不彻底,术后患者症状无明显改善.B组1例术后出现C5脊神经根麻痹,颈椎前路减压后逐渐恢复.术后随访9～38个月,平均20.4个月.两组优良率分别为69.23%（B组）、42.10%（A组）,B组患者手术治疗效果明显优于A组.结论：前后路联合手术治疗重症脊髓型颈椎病应先行后路椎管扩大成形再行前路减压融合,手术效果较好,并发症少,安全性高.     

Postoperative instability after laminoplasty for cervical myelopathy with spondylolisthesis

OBJECTIVE: 76 patients who underwent laminoplasty for cervical spondylotic myelopathy were investigated regarding the impact of preoperative and postoperative degenerative spondylolisthesis on their neurologic outcome. METHODS: Radiographs were obtained 1 year postoperatively to investigate range of motion (ROM), lordotic curvature, and postoperative spondylolisthesis. RESULTS: By 1 year after surgery, 85% of those spondylolistheses present preoperatively had either resolved or improved on neutral lateral radiographs. The cross-sectional area of the spinal cord at the site of spondylolisthesis was measured using preoperative computed tomography myelography. Clinical results were evaluated by the recovery rate using Japanese Orthopaedic Association score. Patients with posterior spondylolisthesis showed a significantly poorer postoperative recovery rate. Intervertebral ROM in patients with preoperative spondylolisthesis was reduced, whereas cervical alignment had not deteriorated after laminoplasty. The group with posterior spondylolisthesis showed a significant reduction in the cross-sectional area of the spinal cord at the site of spondylolisthesis. Postoperative spondylolisthesis appeared in 15 patients, 10 of whom had preoperative spondylolisthesis at an adjacent site. CONCLUSION: The cause of poorer surgical results of those patients with preoperative posterior spondylolisthesis appears to be related to a higher degree of spinal cord compression than with preoperative anterior spondylolisthesis.     

Multivariate analysis of the neurological outcome of surgery for cervical compressive myelopathy

Background The neurological outcome of decompressive surgery for cervical myelopathy is influenced by several factors. Although each factor may have an independent effect, it is more likely that the outcome is influenced by more than one factor. We examined the results of multivariate analysis and multiple regression analysis of the neurological outcome of patients treated by cervical cord decompression. Methods A total of 77 patients with cervical spondylotic myelopathy (43 men, 34 women) and 58 with ossification of the posterior longitudinal ligament (OPLL) (39 men, 19 women) were studied with an average follow-up interval of 8.3 years. The clinical data, neurological and radiological findings, and results of spinal cord evoked potentials (SCEPs) were retrieved from the medical records and included in the analysis. Results Multivariate analysis indicated that the outcome for patients with spondylosis was positively influenced, in order of importance, by increased transverse area of the cord ≥60%, presence of single-level anterior fusion, a high preoperative neurological score, normal epidural SCEPs, and clinical features of brachialgia and cord type. In patients with OPLL, multivariate analysis showed that the long-term outcome was positively influenced, in order of importance, by the presence of mixed or localized OPLL, normal epidural SCEPs, high preoperative neurological score, a single-vertebra spondylectomy with anterior fusion, laminoplasty, widening of the transverse area of the cord ≥40%, and an expansion rate of the spinal canal after laminoplasty ≥40%. Conclusions We suggest that multivariate analysis is useful for assessing the neurosurgical outcome in patients with cervical compressive myelopathy.     

颈椎后路减压术后脊髓后移的临床意义

 目的 探讨颈椎后路全椎板减压和椎管成形术后脊髓后移对多节段脊髓型颈椎病的临床 意义。方法 回顾性分析 2004年 6月至 2007年 9月 65例多节段脊髓型颈椎病患者的病例资料, 男 41例, 女 24例;年龄 39~75岁, 平均 56.3岁。 33例采用颈后路选择性椎板切除术(切除组), 32例采用 颈后路单开门椎管成形术(开门组)。两组患者术前日本矫形骨科学会(Japanese Orthopaedics Associa tion, JOA)评分、颈椎曲度指数的差异无统计学意义。术后 1年, 评估两组的脊髓后移距离、神经功能 (JOA评分)改善率、颈椎曲度指数丢失及轴性症状评分。结果 全部病例均获得 26~47个月的随访, 平均 34个月。切除组术后 1年脊髓后移距离(1.4±0.6) mm, 开门组(3.3±1.2) mm,差异有统计学意义;切除组 JOA评分改善率 60.5%±21.3%, 开门组 61.1%±17.9%,差异无统计学意义;切除组颈椎曲度指数丢失 3.3%±1.7%, 开门组 3.1%±2.4%, 差异无统计学意义;切除组 18.2%(6/33)的患者术后有明显轴性症状, 开门组为 33.3%(10/30), 两组轴性症状临床评分的差异有统计学意义。结论 选择性椎板切除术后脊髓后移距离小于单开门椎管成形术。脊髓后移程度与术后功能恢复程度及颈椎曲度无关, 而与轴性症 状有关。     

Expansive laminoplasty for myelopathy in ossification of the longitudinal ligament

Laminectomy, which had long been used for treatment of cervical spondylotic myelopathy, including ossification of the longitudinal ligament in the cervical spine, had numerous complications such as postoperative malalignment of the cervical spine and vulnerability of the spinal cord caused by total removal of the posterior structures. In 1977 Hirabayashi devised an open door expansive laminoplasty, which is a relatively easier and safer procedure than laminectomy, that eliminated such problems by preserving the posterior elements. The decompression effect of the expansive laminoplasty against a compressed spinal cord is comparable with that of laminectomy and anterior decompression followed by fusion, whereas the expansive laminoplasty has no structural problems and adverse effects on adjacent disc levels that often are associated with anterior decompression followed by fusion. Average recovery rate of expansive laminoplasty for cervical spondylotic myelopathy has been reported to be approximately 60% (Japanese Orthopaedic Association score) and with long term stability. At present, authors consider all patients with cervical spondylotic myelopathy candidates for expansive laminoplasty except for those having preoperative kyphosis and single level lesion without canal stenosis. Two remaining problems of expansive laminoplasty to be solved are prevention of C5,C6 radicular pain and/or paresis, the most frequent complication that occurs in approximately 5% to 10% of the patients, although most complications resolve spontaneously within 2 years, and correction of nonlordotic alignment to lordosis which are essential for posterior decompression effect of expansive laminoplasty by allowing the spinal cord to shift dorsally.     

多节段脊髓型颈椎病术前颈椎曲度对椎管扩大椎板成形术术后神经功能恢复影响

目的探讨多节段脊髓型颈椎病患者术前颈椎曲度与椎管扩大椎板成形术术后神经功能之间的相关性。方法选取2013年1月—2015年12月在第二军医大学附属长征医院实施椎管扩大椎板成形术的70例多节段脊髓型颈椎病患者作为研究对象进行回顾性分析。按照患者术前X线片中的颈椎曲度将患者分为曲度正常组(A组)、曲度变直组(B组)、轻度曲度后凸组(C组),比较3组患者术后各节段脊髓后移距离、神经功能恢复率,并探讨术前颈椎曲度、术后脊髓后移距离与神经功能恢复率之间的相关性。结果 3组患者术后各节段脊髓后移距离组间差异无统计学意义(P0.05)。3组患者术前、术后的组间日本骨科学会(JOA)评分、神经功能恢复率差异均无统计学意义(P0.05);与术前相比,术后3组患者的JOA评分均明显增高,差异具有统计学意义(P0.05)。颈椎曲度与神经功能恢复率、脊髓后移距离之间无相关性。结论术前颈椎曲度变直及轻度后凸的多节段脊髓型颈椎病患者在实施椎管扩大椎板成形术后脊髓神经功能均可改善,曲度变直及轻度后凸可能不再是多节段脊髓型颈椎病行椎管扩大椎板成形术的禁忌证。     

颈椎病伴椎管狭窄手术入路的选择

[目的]探讨颈椎病伴椎管狭窄时的治疗策略及手术入路选择，为颈椎病手术治疗提供有益的经验。[方法]通过收集2002年7月～2003年12月间颈椎病伴椎管狭窄经前路减压术后疗效不佳或症状复发的病例，经分析后再次行后路减压手术治疗并观察其近期疗效；同时随机抽取1985年4月～1992年5月间病情相似而行后路减压的一组病例进行远期疗效随访，对比两组术后疗效。[结果]经前路减压术后脊髓功能（JOA）改善率仅为11．7％，但经后路者为70．3％；而前者经后路减压再手术后脊髓功能改善率可提高至52．8％。[结论]颈椎病伴颈椎管狭窄病例经前路减压术后疗效不佳或症状复发的主要原因在于椎管狭窄因素仍然存在，对上述病例行后路减压再手术治疗后，仍可取得一定的疗效；而最初便经后路减压治疗的此类患者则可取得较显著的远期疗效，提示经后路多节段减压可一期有效地扩大颈椎椎管，从而提高手术治疗颈椎病的疗效。     

Progression of ossification of the posterior longitudinal ligament following en bloc cervical laminoplasty.

BACKGROUND: Ossification of the posterior longitudinal ligament often causes compressive myelopathy. Ossification is a progressive disease, and it has been reported that the area of ossification increases after decompressive surgery. However, it is uncertain how the progression of ossification affects the long-term outcome after cervical laminoplasty. This study was performed to clarify the relationship between the progression of ossification of the posterior longitudinal ligament and the clinical results following en bloc cervical laminoplasty. METHODS: Forty-five patients who were followed for more than ten years after laminoplasty participated in this study. Radiographs and tomograms of the cervical spine of each patient were made before and after the operation and at the time of the latest follow-up. The extent of ossification in the longitudinal and sagittal axes was evaluated. Neurological function was graded with use of the Japanese Orthopaedic Association scoring system. The relationship between the progression of ossification and the score-based rate of recovery was analyzed. RESULTS: Thirty-three (73%) of the patients had progression of ossification of the posterior longitudinal ligament after laminoplasty. Progression was frequent in patients with the mixed type of ossification and in those with the continuous type, whereas it was rare in patients with the segmental type. The patients with progression of the ossification were significantly younger than those without progression (p = 0.018). The Japanese Orthopaedic Association score improved rapidly within one year and continued to improve up to five years after surgery. The score tended to decrease thereafter. For thirteen patients, the score had worsened at the time of the latest follow-up. Three patients had neurological deterioration following an increase in the thickness of the ossification. CONCLUSIONS: Progression of ossification of the posterior longitudinal ligament was often observed during the long-term follow-up period after laminoplasty. Young patients with mixed and continuous types of ossification had the greatest risk for progression. Preventive measures, such as the use of a wider laminar opening during the laminoplasty, should be considered for patients who are at risk for progression of ossification.     

Impact of longitudinal distance of the cervical spine on the results of expansive open-door laminoplasty

STUDY DESIGN: A retrospective study in patients who underwent expansive open-door laminoplasty (ELAP) for cervical myelopathy and in whom the cervical alignment was nonlordotic at the final follow-up to analyze the correlation between the longitudinal distance of the cervical spine and surgical results. OBJECTIVES: To determine the impact of longitudinal distance of the cervical spine on surgical results of ELAP and to propose a new concept, the redundant spinal cord, that may influence patient selection for ELAP. SUMMARY OF BACKGROUND DATA: Results in many studies have demonstrated that postoperative cervical alignment has significant effect on surgical results, and spines that are malaligned are thought to deteriorate. The current surgical data showed that not all patients with postoperative malalignment had poor surgical results. Patients with cervical spondylotic myelopathy (CSM) tended to have better clinical results than those with ossification of the posterior longitudinal ligament (OPLL). METHODS: Results in 70 patients who underwent ELAP for cervical myelopathy with postoperative cervical malalignment were investigated. The longitudinal distance index (LDI) was defined as the length of a vertical line between the posteroinferior edges of C2 and C7 divided by the anteroposterior diameter of C4 and was measured on lateral neutral radiographs at final follow-up. Correlation between LDI and surgical results represented by Japanese Orthopedic Association scores and percentage of recovery were analyzed statistically in each patient. RESULTS: Patients with CSM had smaller LDI and better surgical results than those with OPLL. Weak but significant negative correlation was detected between LDI and percentage of recovery, indicating that longitudinal distance of the cervical spine may have some degree of impact on the surgical results of ELAP. CONCLUSION: A decrease in LDI represents shortening of the cervical spine caused by multiple disc degeneration and may influence surgical results of ELAP by inducing redundancy of the spinal cord in patients with postoperative malalignment.     

颈椎后路三种手术方式对改善多节段颈椎病生理曲度及疗效的远期观察

[目的]本研究通过回顾性分析行颈椎后路手术的多节段脊髓型颈椎病合并后纵韧带骨化(ossificationofposteriorlongitudinalligament.OPLL)患者的颈椎曲率变化、JOA评分改善率以及颈肩轴性痛VAS评分改善率,比较颈椎后路三种手术方式对改善颈椎曲度、神经功能及轴性症状的远期影响.[方法]根据手术方式分三组:A组颈椎后路单开门椎管扩大成形术29例,B组颈椎后路全椎板切除术23例,C组颈椎后路全椎板切除侧块螺钉内固定术26例,记录术前、术后的颈椎曲度、JOA评分及轴性症状等.[结果]JOA评分改善率:3组患者术后与术前相比均有统计学意义(P＜0.05).末次随访时c组最高.颈椎曲度改善率:C组最好,A组次之,B组最差.并发症发生情况:在轴性症状上,3组的VAS评分两两比较有统计学意义(P＜0.05),B组最高,A组次之,C组最低.[结论]采用颈椎后路三种手术方式治疗多节段脊髓型颈椎病合并OPLL均能达到良好的疗效.颈椎后路全椎板切除侧块螺钉内固定术可有效改善神经功能,恢复和保持颈椎曲度,降低轴性症状及C5神经根麻痹发生率.     

Short-term complications and long-term results of expansive open-door laminoplasty for cervical stenotic myelopathy.

BACKGROUND CONTEXT: Laminoplasty has been reported to achieve good operative results for treatment of cervical stenotic myelopathy. However, long-term results and prognostic factors have not been well documented. Among postoperative complications, weakness of the shoulder girdle muscles has been reported as a particular complication of laminoplasty, but the cause is still poorly understood. PURPOSE: Our aim was to clarify the short-term complications and long-term operative results after unilateral open-door laminoplasty and to identify the predictors for operative outcome. STUDY DESIGN: We retrospectively reviewed short-term complications and long-term operative results associated with cervical stenotic myelopathy treated by unilateral open-door laminoplasty. PATIENT SAMPLE: There were 162 men and 42 women with an average age of 57 years who were treated by unilateral open-door laminoplasty in the two institutions. Pathogenesis of myelopathy was cervical spondylosis in 88 patients, cervical disk herniation with a narrow spinal canal in 10, and ossification of the posterior longitudinal ligament in 106. OUTCOME MEASURES: Postoperative complications and their outcomes were examined clinically in 204 patients, and causes of motor paresis were sought with postoperative computed tomography after myelography. Postoperative improvement of clinical symptoms was assessed by recovery rate calculated with the scores of the Japanese Orthopaedic Scoring System in 80 patients. METHODS: The occurrence rate of short-term postoperative complications, causes of motor paresis, and their outcomes were reviewed in 204 patients. Clinical condition was assessed with the Japanese Orthopaedic Scoring System, recovery rate was calculated with the score, and prognostic factors for outcome were studied in 80 patients who were followed up for 5 years or longer (average, 8 years; range, 5-17 years). RESULTS: Occurrence rate of complications, such as muscle weakness, deep infection, closure of opened laminae, and others, was 10.8%. Muscle weakness was observed in 7.8% of the patients. However, this rate decreased in recent years. The cause of motor paresis is not known with certainty, but it may be secondary to operative trauma, posterior shift of the spinal cord, or to displacement of the lamina in the hinge side. Recovery rate of clinical symptoms was 62.1% at the final follow-up. Rates were 63.6% for cervical spondylosis, 87.1% for cervical disk herniation, and 61.3% for ossification of the posterior longitudinal ligament. There was no significant difference between pathologies. Patient age younger than 60 years at the time of operation and less than 1 year's duration of symptoms before surgery were significantly associated with recovery rate of clinical symptoms. Recovery rate was not correlated with either preoperative function judged by the Japanese Orthopaedic Association score or spinal sagittal diameter. CONCLUSIONS: The main cause of postoperative motor paresis of upper extremities is thought to be operative trauma, resulting from such procedures as air-drill and Kerrison rongeur handling. Short-term complications may decrease with the use of nontraumatic procedures. Better operative outcomes may be achieved with careful operative procedures and early operative treatment in the patients with myelopathy.     

Surgical outcome of cervical expansive laminoplasty in patients with diabetes mellitus

STUDY DESIGN: The results from cervical laminoplasty in 18 patients with diabetes mellitus were compared with results from the same procedure in 34 nondiabetic patients matched for age, gender, and disease. OBJECTIVE: To analyze the effects of diabetes mellitus on the surgical outcome after cervical laminoplasty. SUMMARY OF BACKGROUND DATA: There have been no reports on the results of cervical laminoplasty patients with diabetes. METHODS: A retrospective analysis of 18 patients with diabetes mellitus who underwent cervical laminoplasty and 34 nondiabetic patients who underwent the same surgical procedure was undertaken. The postoperative score, intra- and postoperative findings, complications, and radiologic factors were compared between the two groups. In the group with diabetes, the correlation between the recovery rate of the Japanese Orthopedic Association score and the factors indicating the severity of diabetes was assessed. RESULTS: There was no statistical difference between the total Japanese Orthopedic Association scores of the two groups. However, the group with diabetes mellitus showed a poor recovery of sensory function of the lower extremities. Three patients in the group with diabetes had superficial wound complication after surgery. In contrast, none of the patients in the control group had a wound problem. Furthermore, a negative correlation was observed between the recovery rate and the preoperative HbA1 level in the group with diabetes. CONCLUSIONS: Although patients with diabetes mellitus who had cervical myelopathy experienced benefits from cervical laminoplasty similar to those of nondiabetic patients, the patients with diabetes were more likely to have wound complication. Furthermore, the negative correlation between the recovery rate and the preoperative HbA1 value might suggest that long-term diabetes control of more than 2 to 3 months before surgery at least is recommended for a favorable surgical outcome.     

Clinical studies on the significance of en bloc laminoplasty for cervical compressive myelopathy

The aim of this study was clinical evaluation of en bloc laminoplasty for compressive myelopathy. Subjects were 55 patients with severe myelopathy due to ossification of posterior longitudinal ligament or spinal canal stenosis in the cervical spine. The average age at surgery was 58 years old and average follow-up period 25 months. Stable expansion of the spinal canal was shown and the average extent of the canal enlargement in sagittal diameter was 4.8 +/- 1.8 mm roentgenologically. Symmetrical expansion of the canal, good bony fusion and remodelling of the posterior elements of the spine were observed in CT. No marked malalignment or instability of the cervical spine were found, but limitation of flexion-extension movement was noticed. Neurological recovery was remarkable; 44 patients were rated as excellent or good by Robinson's criteria. The average recovery rate was 76.4 +/- 20.1% according to the evaluation system of Japanese Orthopaedic Association (JOA). En-bloc laminoplasty can accomplish a stable expansion of the canal with adequate decompression of the spinal cord.     

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).     

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.     

颈椎病伴椎管狭窄患者再手术问题探讨

目的：探讨颈椎病伴椎管狭窄患者再手术的原因、手术方式及其相关问题。方法：我院2002年7月～2003年12月对40例颈椎病伴椎管狭窄术后疗效不佳或症状复发的患者进行了后路多节段（5个或以上）减压手术。根据其手术治疗方式及影像学资料分析再手术原因，并进行术后疗效评价。结果：经前路手术者再手术的主要原因为：（1）伴有多节段颈椎管狭窄因素时，只选择部分压迫重的节段行减压融合15例；（2）经前路多节段（≥3个节段）减压融合后，相邻节段继续退变，出现新的脊髓压迫表现及椎间不稳定9例；（3）伴有OPLL时，行部分节段前路减压融合后，病变呈进展表现，产生或加重对脊髓的压迫8例。经后路手术者再手术的原因为：（1）后路减压节段不够5例（包括1例前后路联合手术者）；（2）后路减压不充分3例。再手术后随访1．3～2．7年，平均2．1年，所有患者脊髓功能获得一定的提高，JOA评分改善率为51．3％。结论：颈椎病伴椎管狭窄病例再手术的主要原因为椎管狭窄因素仍然存在，经后路多节段（5个或以上）减压手术治疗可彻底去除颈椎管狭窄因素，有效解除脊髓前、后方所受的压迫，可获得较满意的临床疗效。     

Surgical outcomes and prognostic factors of cervical spondylotic myelopathy in diabetic patients

Background  

There have been a few reports on the surgical outcomes of cervical myelopathy in diabetic patients; however, those studies included ossification of the posterior longitudinal ligament. This study investigated whether surgical outcome of expansive laminoplasty (ELAP) for diabetic patients with cervical spondylotic myelopathy (CSM) differs from that for non-diabetic patients and determined prognostic factors in diabetic patients.     

Long-term results of tension-band laminoplasty for cervical stenotic myelopathy: a ten-year follow-up

We reviewed 75 patients (57 men and 18 women), who had undergone tension-band laminoplasty for cervical spondylotic myelopathy (42 patients) or compression myelopathy due to ossification of the posterior longitudinal ligament (33 patients) and had been followed for more than ten years. Clinical and functional results were estimated using the Japanese Orthopaedic Association score. The rate of recovery and the level of postoperative axial neck pain were also recorded. The pre- and post-operative alignment of the cervical spine (Ishihara curve index indicating lordosis of the cervical spine) and the range of movement (ROM) of the cervical spine were also measured. The mean rate of recovery of the Japanese Orthopaedic Association score at final follow-up was 52.1% (SD 24.6) and significant axial pain was reported by 19 patients (25.3%). Axial pain was reported more frequently in patients with ossification of the posterior longitudinal ligament than in those with cervical spondylotic myelopathy (p = 0.027). A kyphotic deformity was not seen post-operatively in any patient. The mean ROM decreased post-operatively from 32.8° (SD 12.3) to 16.2° (SD 12.3) (p < 0.001). The mean ROM ratio was 46.9% (SD 28.1) for all the patients. The mean ROM ratio was lower in patients with ossification of the posterior longitudinal ligament than in those with cervical spondylotic myelopathy (p < 0.001). Compared to those with cervical spondylotic myelopathy, patients with ossification of the posterior longitudinal ligament had less ROM and more post-operative axial neck pain.     

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.