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.     

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.     

Atlantoaxial subluxation associated with ossification of posterior longitudinal ligament of the cervical spine

STUDY DESIGN: Two case reports. OBJECTIVE: To demonstrate two rare cases of atlantoaxial subluxation associated with ossification of the posterior longitudinal ligament of the cervical spine, in which spastic quadriplegia developed. SUMMARY OF BACKGROUND DATA: There are only two reports of an association of diffuse idiopathic skeletal hyperostosis with atlantoaxial subluxation. This condition often accompanies ossification of the posterior longitudinal ligament of the cervical spine, but there is nothing in the literature about the association of ossification of the posterior longitudinal ligament with atlantoaxial subluxation. METHODS: Clinical and radiographic findings of these two cases were demonstrated. In both cases laminoplasty of the cervical spine was performed with occipitoaxial arthrodesis. RESULTS: The spastic quadriplegia of these two patients caused by myelocompression improved after surgical intervention. CONCLUSION: Ossification of the posterior longitudinal ligament of the cervical spine may cause atlantoaxial subluxation.     

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.     

Long-term results of the anterior floating method for cervical myelopathy caused by ossification of the posterior longitudinal ligament

STUDY DESIGN: Results of the anterior floating method used to decompress ossification of the posterior longitudinal ligament were studied for an average postoperative interval of 13 years. OBJECTIVE: To investigate the long-term results of the anterior floating method used to manage ossification of the posterior longitudinal ligament. SUMMARY OF BACKGROUND DATA: The anterior floating method is a technique that differs from the extirpation method used to manage ossification of the posterior longitudinal ligament. Reports of the long-term results from anterior decompression used to manage cervical ossification of the posterior longitudinal ligament are rare. METHODS: The anterior floating method was used to decompress cervical ossification of the posterior longitudinal ligament in 63 patients. These patients were followed for more than 10 years with neurologic evaluations using a scoring system proposed by the Japanese Orthopedic Association (JOA score). RESULTS: The recovery rate was 66.5% at 10 years and 59.3% at 13 years, the time of the final survey. Operative outcomes most closely reflected the preoperative duration and severity of myelopathy (JOA score) and the preoperative cross-sectional area of the spinal cord. There was no correlation with the canal narrowing ratio or the thickness of ossification of the posterior longitudinal ligament. Delayed deterioration was attributed to an original inadequate decompression and progression of ossification of the posterior longitudinal ligament outside the original operative field. There was no evidence of significant recurrent ossification of the posterior longitudinal ligament within the margins of prior decompression. CONCLUSIONS: The anterior floating method appears to yield adequate long-term outcomes when used to manage ossification of the posterior longitudinal ligament.     

Ossification of posterior longitudinal ligament of the cervical spine in non-Japanese Asians

"The Japanese disease," ossification of the posterior longitudinal ligament, is not confined to the Japanese only. A similar incidence of 0.8% was found in this study among non-Japanese Asians. Of 5167 patients who attended the Mount Elizabeth Hospital in Singapore for cervical spine complaints, 43 patients were found to have ossification of the posterior longitudinal ligament, forming the largest non-Japanese series. All but one patient were of Mongolian origin, and males were affected four times more commonly than females. Diabetes mellitus was present in 16%. There was a significant association between ossification of the posterior longitudinal ligament and calcification of other cervical paraspinal ligaments. It is suggested that a generalized tendency to calcification may be an important etiological factor in ossification of the posterior longitudinal ligament. Four of the patients required surgery, and in our experience, anterior spinal fusion with removal of the ossified ligament or multilevel laminoplasty gives satisfactory results.     

Surgical strategy for ossification of the posterior longitudinal ligament in the cervical spine

Ossification of the posterior longitudinal ligament is a common cause of cervical myelopathy, and controversy remains regarding surgical options. Between January 2004 and December 2007, a total of 164 patients with ossification of the posterior longitudinal ligament in the cervical spine who underwent surgical treatment at the authors' institution were included in this study. The choice of surgical option was based on pathological extent and cervical alignment. Short-segment pathology was treated via the anterior approach and long-segment pathology via the posterior approach. When the posterior approach was selected, laminoplasty was performed for the patients with cervical lordosis and laminectomy with fusion for those with cervical kyphosis. Consequently, anterior corpectomy and fusion was performed in 91 patients, laminoplasty in 41 patients, and laminectomy and instrumented fusion in 32 patients. The Japanese Orthopedic Association scoring system was used to evaluate patients' neurological status, and related complications were also recorded. Clinical results between different approaches and techniques were compared at mid-term follow-up.Based on the results of this study and a review of previous literature, no significant differences existed between different approaches and techniques for patients with mild ossification of the posterior longitudinal ligament, but anterior corpectomy and fusion had significantly better results in patients with severe ossification of the posterior longitudinal ligament. With respect to the posterior approach, laminectomy and instrumented fusion improved the surgical results of patients with cervical kyphosis, but a high incidence of C5 palsy existed simultaneously.     

Cervical myelopathy caused by hypoplasia of the atlas and ossification of the transverse ligament--case report

A 79-year-old Japanese female presented with symptomatic cervical myelopathy caused by a hypoplastic posterior arch of the atlas and ossification of the transverse ligament. Neuroradiological examination demonstrated a hypoplastic posterior arch of the atlas and ossification of the transverse ligament. The cervical spinal cord was compressed at the level of the atlas by both the hypoplastic posterior arch of the atlas and the ossification of the transverse ligament. The patient underwent C-1 laminectomy, which arrested the progressive myelopathy and resulted in a good recovery. Atlas hypoplasia with ossification of the transverse ligament may be associated with Asian ethnicity.     

多节段脊髓型颈椎病合并后纵韧带骨化症患者的手术方式探讨

目的探讨多节段脊髓型颈椎病合并局灶型后纵韧带骨化症患者手术入路的选择、不同手术方式及结果。方法本组56例多节段脊髓型颈椎病合并局灶型后纵韧带骨化症患者,18例施行前路椎体及病灶切除减压 髂骨或钛网植骨钢板内固定术。30例行后路全椎板减压 Axis侧块钢板固定 关节突植骨。前后路联合手术8例．3例后路术后一期联合前路手术,5例为后路术后症状改善不明显或症状有加重,二期行前路手术。所有病例随访2年以上,采用JOA评分,观察前路、后路和前后路联合3种手术入路的减压效果。结果随访56例,颈前路患者的手术改善率69．69%;颈后路患者的手术改善率65．04%;前后路联合患者的手术改善率75．25%。3种术式存在显著差别。并发症发生率以颈后路手术者最低。结论多节段脊髓型颈椎病合并局灶型后纵韧带骨化症患者手术效果虽然以前后路联合手术为最好,但并发症发生率也最高,而颈后路手术并发症发生率最低。因此应根据患者体质、病情以及影像学表现仔细分析。选择相应的手术方式。     

Anterior floating method for cervical myelopathy caused by ossification of the posterior longitudinal ligament

Ossification of the posterior longitudinal ligament lessens the sagittal diameter of the cervical canal and compresses the spinal cord anteriorly, and may produce severe disabling myelopathy. The anterior floating method is one of the anterior decompression and reconstructions used in the treatment of cervical myelopathy caused by ossification of the posterior longitudinal ligament. This procedure consists of subtotal resection of vertebral bodies and discs, with slight thinning and release of the ossified ligament using air instrumentation. This is followed by reconstruction of the cervical spine using autogenous strut bone graft accompanied by postoperative application of a halo vest. This method is indicated for patients who present with moderate or severe myelopathies, and especially in those where the canal narrowing ratio exceeds 60%. This radical procedure causes decompression of the spinal cord and restores its function by enlarging the neural canal with anterior migration of the ossified ligament. The procedure minimizes the extent of surgical invasions and avoids damage to the neural tissue, because it does not require the removal of the ossification of the posterior longitudinal ligament. It also stops postoperative regrowth of the ossification. The operative results with long term followup indicate a 71% average recovery rate based on the criteria established by the Japan Orthopedic Association.     

Long-term follow-up results of anterior interbody fusion applied for cervical myelopathy due to ossification of the posterior longitudinal ligament

STUDY DESIGN: A long-term follow-up study was carried out in 30 patients who underwent anterior interbody fusion for cervical myelopathy associated with ossification of the posterior longitudinal ligament (OPLL). OBJECTIVE: To investigate whether anterior interbody fusion without decompression is an appropriate surgical method for long-term relief of cervical OPLL myelopathy. SUMMARY OF BACKGROUND DATA: Several studies of operative results after posterior decompression for cervical myelopathy due to ossification of the posterior longitudinal ligament have been reported. There has been no report about anterior interbody fusion without decompression. The postoperative results of this treatment method applied in cervical OPLL myelopathy have been evaluated by the authors of the present study for more than 10 years. No reports on such a long-term follow-up study have been published in the literature. METHODS: Thirty patients who underwent anterior interbody fusion for cervical OPLL myelopathy were evaluated clinically and radiographically. The mean follow-up period was 14.7 years (range, 10-23 years). RESULTS: Clinical results were evaluated according to Okamoto's classification. At the time of the final follow-up evaluation, 16 patients had improved in functional score by two grades, and their surgical results were regarded as excellent; eight patients improved by one grade, and their clinical outcomes were regarded as good; five patients showed no change; and the condition of one patient deteriorated. As for radiographic analysis, the type of ossification had changed in four cases. Ossification width and thickness increased in 26 patients. Postoperative alignment of the cervical spine showed kyphosis in three patients, straight spine in 11 patients, and lordosis in 16 patients. CONCLUSION: Anterior interbody fusion without decompression is an effective treatment for cervical OPLL myelopathy that resulted in stable long-lasting conditions.     

Unusual appearance of an en plaque meningioma of the cervical spinal canal. A case report and literature review

STUDY DESIGN: A case report of a patient with cervical spinal cord and nerve root compression caused by a meningioma en plaque together with calcification of the posterior longitudinal ligament is presented,with a review of the literature. OBJECTIVE: To present the diagnosis of a calcified dural meningioma en plaque, with extradural extension into the ligamentum flavum, in a woman with cervical myelopathy and neuropathy. SUMMARY OF BACKGROUND DATA: This case demonstrates that the cervical spine can be involved in dural meningioma en plaque with calcifications, in a manner mimicking ossification of the ligamentum flavum, which has never been previously reported. METHODS: A patient presenting with cervical cord and nerve root compression caused by ossification of the posterior longitudinal ligament and a concurrent calcified dural meningioma en plaque was treated surgically and has made a gradual recovery. Imaging studies,surgical findings, and histopathologic evaluation were analyzed to support the diagnosis. RESULTS: At surgery, ossification of the posterior longitudinal ligament was noted, along with a calcified lesion involving the posterior cervical dura and the adjacent ligamentum flavum. A calcified meningioma was diagnosed by histopathologic examination of the dural-based lesion. CONCLUSION: Although previously not described, the diagnosis of calcified dural meningioma en plaque should be considered in all patients presenting with spinal cord and/or nerve root compression,even at cervical levels. Although ossification of the posterior longitudinal ligament and ossification of the ligamentum flavum are more common etiologies of partially circumferential spinal calcification, dural-based meningiomas with extension into the surrounding ligaments demand early recognition because they can be associated with a poorer prognosis.     

后纵韧带切除在脊髓型颈椎病前路手术中的应用

目的：探讨脊髓型颈椎病前路手术中行后纵韧带切除的指征。方法和注意事项。方法：回顾性分析了自2001年1月-2002年6月在颈椎前路手术中行后纵韧带切除的38例脊髓型颈椎病患者的临床资料和随访结果。结果：30例获得随访。平均改善率为72.6%，优10例，占33.3%；良12例，占40%；中6例，占20%；差2例，占6.7%，结论：对合并后纵韧带肥厚压迫颈髓或合并颈椎间盘脱出至硬膜外腔的脊髓型颈椎病患者行前路手术中，需切除后纵韧带。彻底减压，疗效满意。     

分期后路-前路联合手术治疗颈椎后纵韧带骨化症伴重度脊髓型颈椎病的疗效分析

目的:探讨分期后路-前路联合手术治疗颈椎后纵韧带骨化症(ossification of the posteriorl ongitudinal ligament,OPLL)伴重度脊髓型颈椎病患者的疗效。方法:2005年1月至2008年6月共收治颈椎OPLL伴重度脊髓型颈椎病患者35例,均先行后路椎板切除减压植骨内固定术,术后3～6个月,行影像学检查均发现颈髓前方尚有压迫和/或神经根麻痹,再行前路椎体次全切除及骨化物切除减压植骨内固定术。术前及第一、第二次术后(末次随访时)行JOA(17分法)评分,分析比较术前、术后评分并计算改善率。结果:一期后路手术后3例患者出现C5神经根麻痹症状,经保守治疗后1例症状消失,2例有所减轻,二期前路手术后症状消失。2例患者前路术后出现脑脊液漏,经适当加压等保守治疗后愈合。本组平均随访时间21.5±5.0个月,术前JOA评分6.9±2.3分,第一次后路手术后JOA评分11.2±4.2分,改善率为(43±22)%;二期前路手术后JOA评分14.0±3.8分,改善率为(48±20)%,与未治疗之前相比改善率为(70±21)%。第一次后路手术后改善率≤35%的患者(17例),二期前路手术后均取得较好的改善率,54%～68%,平均(60±16)%。结论:对于颈椎OPLL伴重度脊髓型颈椎病患者,后路手术后3～6个月,若前方尚有压迫和/或神经根麻痹者,尤其是后路手术改善率≤35%的患者,二期前路手术可进一步提高手术改善率,达到良好的神经功能恢复效果。     

Ossification of the posterior longitudinal ligament. Results of anterior cervical decompression and arthrodesis in sixty-one North American patients

BACKGROUND: Ossification of the posterior longitudinal ligament is commonly associated with cervical myelopathy. Surgical treatment is a matter of controversy. We report on a series of patients who were managed with anterior cervical decompression and arthrodesis for the treatment of cervical myelopathy associated with ossification of the posterior longitudinal ligament. METHODS: We retrospectively reviewed the records for all sixty-five patients who had been managed with anterior decompression and arthrodesis for the treatment of cervical ossification of the posterior longitudinal ligament and associated neurologic compression from 1982 to 2001. Sixty-one patients (thirty-nine men and twenty-two women) were followed for at least two years (or until the time of death). The average number of vertebrae resected was 2.2. The average duration of follow-up for the sixty surviving patients was four years (range, two years to fifteen years and four months). The preoperative, six-week postoperative, and final follow-up clinical status (including neurological function as assessed with the Nurick grading system) was recorded for each patient. RESULTS: Fifty-six of the sixty-one patients had neurological improvement, with an average improvement of 1.5 Nurick grades at the time of the final follow-up. Eight patients had absent dura at the time of surgery and, of these, five had development of a cerebrospinal fluid fistula. Eight patients had development of new neurological signs and/or symptoms in the upper extremity postoperatively. Eight patients required reoperation because of a painful pseudarthrosis (one patient), strut-graft dislodgment (three), cerebrospinal fluid leakage (three), or compression of a nerve root caudad to the area of the original procedure (one). One patient died as the result of cardiac arrest on the third postoperative day. Fifty-eight patients had an osseous fusion, one had an asymptomatic nonunion, and one had a symptomatic pseudarthrosis that was treated with revision surgery. CONCLUSIONS: Anterior decompression and arthrodesis is an effective way to achieve pain relief and neurological improvement in North American patients of non-Asian descent who have cervical myelopathy associated with ossification of the posterior longitudinal ligament. The risk of durocutaneous fistula, graft dislodgment, and postoperative neurological symptoms appears to be high in patients with cervical myelopathy associated with this condition.     

Computed tomography in ossification of the posterior longitudinal ligament in the cervical spine.

Computed tomography of the cervical spine has been carried out on 21 patients with the ossification of the posterior longitudinal ligament. There was a correlation between the shape and the extent of ossification and the type of myelopathy. Computed tomography is important for operative intervention.     

Axial transverse tomography of the cervical spine narrowed by ossification of the posterior longitudinal ligament.

Ossification of the posterior longitudinal ligament in the cervical region is generally regarded as a rare disease, though a Japanese series of 185 cases has been reported. The main symptoms arise from a myelopathy, the degree of which varies from moderate to severe, due to stenosis of the spinal canal. In order to clarify the relationship between the severity of symptoms and the cross-sectional area of ossification, axial transverse tomography of the cervical spine has been carried out on twenty-six patients at intervals of 5 millimetres over the full extent of the ossification. In this way the cross-sectional areas of the ossified tissue and of the spinal canal were calculated. The former varied from a minimum of 0.8 to a maximum of 1.8 square centimetres. In cases of severe myelopathy the ossification was mainly at the fourth and fifth cervical levels and the stenosis ration exceeded 30 per cent.     

Untreated hypophosphatemic vitamin D-resistant rickets with symptomatic ossification of the ligamentum flavum.

An adult case of untreated hypophosphatemic vitamin D-resistant rickets with symptomatic ossification of the ligamentum flavum in the thoracic region is reported and discussed with regard to the calcium metabolism and the ligamentous ossification. Factors influencing ossification of the ligamentum flavum may be mechanical stress on the spine and an increase in calcium retention.     

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.     

Quantitative assessment of surgical decompression of the cervical spine with cine phase contrast magnetic resonance imaging

OBJECTIVE: We measured cerebrospinal fluid flow velocity by use of cine phase contrast magnetic resonance imaging to quantitate the effectiveness of surgical decompression in patients with cervical myelopathy. METHODS: Forty-seven patients with cervical myelopathy attributable to either spondylosis or ossification of the posterior longitudinal ligament were studied. Thirty-five patients underwent anterior cervical decompression and fusion; 12 others underwent expansive laminoplasty. Patients were examined preoperatively and postoperatively by use of a 1.5-T scanner with a pulse-gated cine phase contrast sequence. Cerebrospinal fluid flow direction and velocity in the ventral subarachnoid space were determined at the C1 and T1 levels. Forty-four healthy control subjects were examined to determine normal flow velocity parameters. Severity of cervical myelopathy was evaluated preoperatively and postoperatively by use of Japan Orthopedic Association scores to calculate the extent of recovery. RESULTS: Preoperatively, cerebrospinal fluid flow velocity in the caudal direction was significantly lower at both C1 and T1 than velocities measured in healthy controls. Both decompressive procedures essentially returned patient velocities to control values. Clinical recovery from myelopathy did not differ between anterior and posterior decompression. Postoperative increase in flow velocity correlated with clinical recovery after posterior (P < 0.0008) but not anterior decompression. CONCLUSION: Cine phase contrast magnetic resonance imaging provides quantitative assessment of cervical spine decompression, with particularly good clinical applicability to posterior procedures.