Co-existence of ossification of the nuchal ligament is associated with severity of ossification in the whole spine in patients with cervical ossification of the posterior longitudinal ligament -A multi-center CT study-

Background

Previous studies have shown that patients with cervical ossification of the posterior longitudinal ligament (OPLL) often have co-existing ossification of the nuchal ligament (ONL). However, no studies have focused on ONL and its relevance to the severity of OPLL or ossification of other spinal ligaments, such as anterior longitudinal ligament (OALL), ligamentum flavum (OLF), and supraspinous/interspinous ligament (OSIL).

Clinical and radiological study of ossification of the anterior longitudinal ligament in the cervical spine

Twenty-seven patients with ossification of the anterior longitudinal ligament (OALL) in diffuse idiopathic skeletal hyperostosis (DISH) in the cervical region were diagnosed among 2000 individuals during 10 months and analyzed clinically and radiologically by two neurosurgeons. Sex distribution was 20 men and 7 women with ages ranging from 57 to 82 years (average: 72.3 y.o.). Main signs and symptoms were dysesthesia of the upper extremities, stiff neck, dizziness and dysphagia (33%). Three patients had diabetes mellitus, 14 had hypertension, and 15 had hyperuremia. Ossification of the posterior longitudinal ligament (OPLL) co-existed in 18 patients (66%). Number of vertebral bodies with cervical OALL ranged from 4 to 6 (average: 4.8) and thickness of ossification of the anterior longitudinal ligament was from 2 to 6 (average: 3.1) mm. Originally we divided OALL in the cervical region into 3 types, nodular-type; 16 cases, continuous-type; 7 cases, and mixed-type; 4 cases. Small OPLL can be diagnosed by either cervical CT or myelo-CT. DISH is thought to be a benign clinical entity, but patients with OALL in DISH, accompanied by OPLL and those accompanied by dysphasia are frequently encountered and sometimes may be treated surgically.     

胸椎黄韧带骨化症的治疗方法选择

目的研究胸椎黄韧带骨化症（ｏｓｓｉｆｉｃａｔｉｏｎｏｆｌｉｇａｍｅｎｔｕｍｆｌａｖｕｍ,ＯＬＦ）诊断与手术治疗的特点。方法采用回顾性研究方法对手术治疗的胸椎ＯＬＦ的病例进行总结分析。结果总计７２例ＯＬＦ,其中局灶型１５例,连续型４１例,跳跃型１６例;３７．５％合并颈椎后纵韧带骨化症（ｏｓｓｉｆｉｃａｔｉｏｎｏｆｐｏｓｔｅｒｉｏｒｌｏｎｇｉｔｕｄｉｎａｌｌｉｇａｍｅｎｔ,ＯＰＬＬ）,１９．４％合并胸椎ＯＰＬＬ,９．７％合并胸椎间盘突出,１．４％同时合并颈、胸、腰椎ＯＰＬＬ,９．７％合并腰椎间盘突出。结论上述特点是胸椎ＯＬＦ诊断及选择治疗方法时要特别考虑的因素。“揭盖式”椎管后壁切除减压是治疗本病安全、有效的手术方法。     

Ossification of the ligamentum flavum of the cervical spine

AIM: Ossification of ligamentum flavum (OLF) mainly occurs in the thoracic spine, and rarely in the cervical spine. To clarify its etiology; the features of OLF in the cervical spine were reviewed in 50 reported cases. METHODS: Age, sex, location of OLF, classification of OLF, radiographic findings, computed tomography (CT) findings, magnetic resonance imaging findings, association of ossification of the posterior longitudinal ligament (OPLL), association of OLF in other spinal regions, and association of diffuse idiopathic skeletal hyperostosis (DISH) were analyzed in 23 detailed cases. RESULTS: Association of OPLL was observed in 7 of 20 cases and 4 of these 7 OPLL cases were at C2-4. Association of OLF in other spinal regions was recognized in 7 of 15 cases. DISH was also present in 3 of 7 cases. Local kyphosis was recognized in 10 of 12 cases by radiography. CT showed facet hypertrophy in 13 of 15 cases and lamina hypertrophy in 14 of 16 cases. Patients with OLF at C2-4 had high rates of local kyphosis and association of hyperostotic state, suggesting both local factors and systemic hyperostotic factors are involved in the formation of OLF of the upper cervical spine. CONCLUSION: Local factors may be strongly related to the formation of OLF of the middle or lower cervical spine.     

Ossification of the spinal ligament. A radiographic reevaluation in Bologna, Italy

A radiographic reevaluation of cervical spine films of 1,258 adult patients and of thoraco-lumbar spine films of 488 of these was performed at the Rizzoli Orthopaedic Institute (Bologne, Italy), in order to detect ossification of the posterior longitudinal ligament (OPLL), the anterior longitudinal ligament (OALL), the yellow ligament (OYL) and the nuchal ligament at the cervical level, and OPLL, OALL and OYL at the thoraco-lumbar level. The incidence of OALL, OYL and ossification of the nuchal ligament corresponded with those previously reported in the literature. Cervical OPLL was found in 1.83%, with a definite prevalence in the 45-64 age group where the figure was 2.83%. This incidence is much higher than that hitherto reported in Caucasians, and is nearly the same as that in Japan. Possible explanations for this discrepancy are proposed.     

A radiological population study on the ossification of the posterior longitudinal ligament in the spine

This paper reports the results of a radiological population study on the ossification of the posterior longitudinal ligament (OPLL) in both the cervical and the thoracic spine among Japanese. The study was carried out in the Yachiho-mura district in the central part of Japan, where 5074 people were living. X-ray examinations were made of 1058 of the people; there were 440 men and 618 women, 50 or more years of age. The roentgenograms showed 34 cases of OPLL in the cervical spine (3.2%): 19 men (4.3%) and 15 women (2.4%). The condition was most frequently observed at the level of C-4. Radiological classification showed 18 cases of the segmental type, 11 of the continuous type, and five of a mixed type. There were eight cases of OPLL in the thoracic spine (0.8%), four in men (0.9%) and four in women (0.6%). OPLL in the thoracic spine was most frequently observed at the midthoracic levels. All eight cases showed a continuous type of ossification. There were three subjects with OPLL in both the cervical and the thoracic spine. Therefore, the number of subjects with OPLL in either the cervical or the thoracic spine was 39 (3.7%) total.     

胸椎后纵韧带骨化的临床特点及治疗策略

目的回顾研究手术治疗胸椎后纵韧带骨化症(OPLL)的临床特点及治疗方法。方法1991至2005年手术治疗胸椎OPLL55例,男19例,女36例;年龄35～73岁,平均51.9岁。均伴有脊髓损害。手术方式包括单纯椎管后壁切除术34例、前方OPLL切除减压术15例以及前后路联合手术6例。结果55例中36例(65.5%)合并胸椎黄韧带骨化(OLF),18例(32.7%)合并颈椎OPLL。单纯发生于上胸椎的OPLL13例(23.6%),中胸椎12例(21.8%),下胸椎及胸腰段17例(30.9%),广泛分布者13例(23.6%)。43例获得随访,平均随访时间47.1个月(6～168个月)。37例神经功能有改善,改善率为76.6%,无改善2例,加重4例。前方入路获随访者13例,其中3例症状加重,余改善率平均为82.9%(42.9%～100%)。后路椎管后壁切除术获随访者25例,1例无改善,1例加重,余改善率平均为72.6%(22.2%～100%)。前后路联合手术获随访5例,1例无改善,余改善率平均为83.9%。结论胸椎OPLL常合并胸椎OLF及颈椎OPLL。上胸椎OPLL合并颈椎管狭窄可一期行颈后路单开门及上胸椎椎管后壁切除术。两个节段以内的OPLL且不合并有造成脊髓压迫的胸椎OLF可行前路OPLL切除减压术,否则行后路椎管后壁切除术。单节段的OPLL合并胸椎OLF可行前后路联合手术。     

A radiological population study on the ossification of the posterior longitudinal ligament in the spine

Summary This paper reports the results of a radiological population study on the ossification of the posterior longitudinal ligament (OPLL) in both the cervical and the thoracic spine among Japanese. The study was carried out in the Yachiho-mura district in the central part of Japan, where 5074 people were living. X-ray examinations were made of 1058 of the people; there were 440 men and 618 women, 50 or more years of age.The roentgenograms showed 34 cases of OPLL in the cervical spine (3.2%): 19 men (4.3%) and 15 women (2.4%). The condition was most frequently observed at the level of C-4. Radiological classification showed 18 cases of the segmental type, 11 of the continuous type, and five of a mixed type.There were eight cases of OPLL in the thoracic spine (0.8%), four in men (0.9%) and four in women (0.6%). OPLL in the thoracic spine was most frequently observed at the midthoracic levels. All eight cases showed a continuous type of ossification.There were three subjects with OPLL in both the cervical and the thoracic spine. Therefore, the number of subjects with OPLL in either the cervical or the thoracic spine was 39 (3.7%) total.This study was subsidized by the Japanese Ministry of Public Health and Welfare     

对颈椎间盘突出症的再认识

报告经ＣＴ、ＭＲＩ及手术证实的颈椎间盘突出症２７例，着重讨论了颈椎间盘突出症与颈椎病的关系，认为颈椎间盘退变是两者的共同病理基础。颈椎间盘突出不仅是单纯的髓核突出，晚期还可伴有骨赘增生、椎管狭窄、ＯＰＬＬ等改变。作者认为，凡是与颈椎间盘突出有关的颈椎病变都应归入颈椎间盘突出症的范畴。同时对颈椎间盘突出的诊断亦作了详细讨论     

Cervical spinal cord injury caused by vertebral body fracture in a patient with concomitant OALL and OPLL

We encountered a case of cervical spinal cord injury associated with cervical vertebral dislocation fracture that occurred in a patient with concomitant ossification of the anterior and posterior longitudinal ligaments. The cervical vertebrae were injured by hyperextension in a car accident. On admission, shearing fracture was noted in the OALL region and vertebral body OPLL region over the posterior column at the fourth cervical level, but no dislocation or neurological findings were noted. Restlessness occurred and caused dislocation several hours after admission, leading to complete injury of the cervical spinal cord. The patient died of complications after 3 weeks. Vertebral body fracture complicated by both OALL and OPLL is very rare, and only four cases have been reported. Since vertebral injury causes delayed fracture/dislocation after a symptom-free interval in cases with ligament ossification, accurate clinical evaluation early after injury and early fixation are necessary.     

Symptomatic ossification of the anterior longitudinal ligament with stenosis of the cervical spine: a report of seven cases

Seven men with a mean age of 63.9 years (59 to 67) developed dysphagia because of oesophageal compression with ossification of the anterior longitudinal ligament (OALL) and radiculomyelopathy due to associated stenosis of the cervical spine. The diagnosis of OALL was made by plain lateral radiography and classified into three types; segmental, continuous and mixed. Five patients had associated OALL in the thoracic and lumbar spine without ossification of the ligamentum flavum. All underwent removal of the OALL and six had simultaneous decompression by removal of ossification of the posterior longitudinal ligament or a bony spur. All had improvement of their dysphagia. Because symptomatic OALL may be associated with spinal stenosis, precise neurological examination is critical. A simultaneous microsurgical operation for patients with OALL and spinal stenosis gives good results without serious complications.     

胸椎黄韧带骨化症合并脊髓型颈椎病的临床诊断要点

目的总结胸椎黄韧带骨化症合并脊髓型颈椎病的临床特点,探讨避免漏诊胸椎黄韧带骨化症的方法。方法对比分析胸椎黄韧带骨化症合并脊髓型颈椎病和单纯脊髓型颈椎病的临床表现、影像学表现、JOA评分的异同。结果共收集35例胸椎黄韧带骨化症合并脊髓型颈椎病病例,其中20例合并连续型颈椎后纵韧带骨化和/或弥漫性特发性骨肥厚症,14例是因颈椎MRI发现上胸椎黄韧带骨化后进一步行全胸椎MRI检查后确诊;胸椎黄韧带骨化症合并脊髓型颈椎病者的上肢功能评分构成比较单纯脊髓型颈椎病者为高(p<0.05)。结论胸椎黄韧带骨化症合并脊髓型颈椎病的诊断须综合分析病史、体征和影像学表现;JOA脊髓功能评分可以为其确诊提供帮助。     

An epidemiological study on the ossification of the anterior longitudinal ligament of the spine

An epidemiological study was carried out in connection with the multiphasic screening examination of 1,057 people (442 men and 615 women) in the village of Yachiho. The purpose of this study was to define the etiology of OALL (ossification of the anterior longitudinal ligament) and disc narrowing. The prevalence of disc narrowing increased with age, but OALL was not correlated with aging. OALL was found more frequently in men, but disc narrowing showed no difference between each sexes. The body height and weight-height index were higher in the OALL cases. The body height shrinkage by aging was greater in the patients with disc narrowing cases. The index of thoracic kyphosis was higher in the OALL cases than in the patients with disc narrowing ones. OALL was associated with ossification of the other ligaments of the spine, but disc narrowing was not. This study suggests that despite some similarities, OALL is etiologically different from disc narrowing.     

Circumspinal decompression for thoracic myelopathy due to combined ossification of the posterior longitudinal ligament and ligamentum flavum

Ossification of the posterior longitudinal ligament (OPLL) combined with ossification of the ligamentum flavum (OLF) in the thoracic spine can result in serious myelopathy, leading to circumferential compression of the spinal cord in advanced stages of the disease. The authors performed circumspinal decompression (circumferential decompression of the spinal cord) on these patients. This operation consists of two steps: posterior and lateral decompression of the spinal cord by removal of the OLF (first step) and anterior removal of the OPLL for anterior decompression (second step), followed by interbody fusion. In the first step, two deep parallel gutters, covering the extent of the OPLL to be removed anteriorly, are drilled down from the rear into the vertebral body along both sides of the dura to easily and safely remove the OPLL anteriorly at the second step. In the second step, the surgical approach varies according to the affected level; costotransversectomy in the upper thoracic spine and standard thoracotomy in the middle or lower thoracic spine. According to the authors, circumspinal decompression is not an easy procedure, but from their results in 10 patients, they identify it as a radical and promising surgical procedure.     

Cervical spine stenosis due to ossification of the posterior longitudinal ligament in Italian patients: surgical treatment and outcome

Ossification of the posterior longitudinal ligament (OPLL) of the cervical spine is a frequent pathological entity in people of Japanese and Asian extraction and is reported with increasing frequency also in the USA; on the contrary, reports in the European and particularly in the Italian literature remain rare. This paper describes 8 Italian patients with cervical spine stenosis due to OPLL extending three to five vertebral segments (and above C3 in four cases). Magnetic resonance imaging shows the extent of the ossification well in terms of height and cord compression, while computed tomography is useful to measure the thickness of the bone mass and the residual spinal canal. Anterior cervical decompression by discectomy, corpectomy, and removal of the ossified ligament is the treatment of choice and results in clinical improvement in most cases. Decompressive laminectomy may be reserved for patients with ossification extending to four or five levels and above C3. The surgical technique and intraoperative findings are discussed. Received: 30 March 1998     

胸椎黄韧带骨化症合并脊髓型颈椎病手术方案选择

目的 探讨胸椎黄韧带骨化(ossification of ligamentum flavum,OLF)合并脊髓型颈椎病(cervical spondylotic myelopathy,CSM)手术方案的选择.方法 1991年1月至2003年1月,手术治疗胸椎OLF合并CMS患者56例,其中40例获得2年以上随访,男22例,女18例;确诊时年龄27～70岁,平均58岁;病程1～120个月,平均16.5个月.其中OLF 25例,OLF合并后纵韧带骨化(ossification of posterior longitudjnal ligament,OPLL)12例,OLF合并胸椎间盘突出3例;同时合并颈椎OPLL 23例,退变性颈椎管狭窄17例.18例一期行颈后路"单开门"椎板成形术+上胸椎椎管后壁切除术,9例一期行胸椎管后壁切除术,13例分期行颈后路和胸椎管后壁切除术.结果 40例患者的随访时间为24～227个月,平均67.5个月.根据改良Epstein手术疗效评定标准评价优良率,18例一期行颈后路"单开门"椎板成形术+上胸椎椎管后壁切除术者为88.9%(16/18),9例行胸椎管后壁切除术者为66.7%(6/9);13例分期行颈后路和胸椎管后壁切除术者为53.8%(7/13).结果 显示分期手术者术后优良率低于一期手术者,手术间隔时间在1年以内者的优良率高于间隔1年以上者.结论 上胸椎OLF合并CSM者应一期行颈椎和上胸椎脊髓减压术;下肢症状严重而上肢症状轻微者应先行胸脊髓减压术;上、下肢症状均重者应一期或分期行颈脊髓减压术和胸脊髓减压术,而分期手术者的手术间隔时间不宜过长.     

Treatment of myelopathy due to cervicothoracic OPLL via open door laminoplasty

STUDY DESIGN: Postoperative long-term follow-up study of open door laminoplasty for the ossification of the posterior longitudinal ligament (OPLL) in the thoracic spine. OBJECTIVES: Techniques and outcomes of open door laminoplasty were described. The efficacy of this procedure was discussed and compared with other surgical methods for thoracic OPLL reported in the literature. SUMMARY OF BACKGROUND DATA: OPLL of the thoracic spine is often associated with cervical OPLL or ossification of the yellow ligament (OYL) of the thoracic spine; therefore, it is extremely difficult to determine the most appropriate surgical therapeutic procedure. There are very few detailed reports about extensive laminoplasty for OPLL of the thoracic spine. METHODS: The subjects included in this study consisted of 13 consecutive patients of thoracic OPLL who were surgically treated between 1994 and 2003 by the open door laminoplasty using the spinal processes and ligament complex as spacers for the open side. The number of manipulated lamina, including the cervical spine, was from 7 to 14 (mean 10 laminae), the follow-up period was 75 months on average. We evaluated the clinical symptoms by the JOA scoring method and postoperative bone union and thoracic kyphosis by plain x-ray photograph and computed tomography. RESULTS: Postoperatively, the JOA score improved from an average of 5.5 to 8.5 out of a maximum of 11 points and the mean recovery rate by Hirabayashi method was 54.5%. In all cases, bone union was seen at the hinge side between the opened lamina and the lateral mass. Neither restenosis of the opened lamina nor marked progression of kyphosis were seen on the final follow-up observation in any patient. There was no postoperative spinal cord injury. CONCLUSIONS: Open door laminoplasty is a useful procedure for OPLL of the thoracic spine. This method enables wide-range posterior decompression, especially for the continuous type OPLL extending from the cervical spine to the thoracic spine, even if the apex of the thoracic kyphosis is included.     

Cervical myelopathy resulting from combined ossification of the ligamentum flavum and posterior longitudinal ligament: report of two cases and literature review

Background contextIn the cervical spine, the combination of ossification of the ligamentum flavum (OLF) and ossification of the posterior longitudinal ligament (OPLL) is rarely seen. There have been only four cases reported in the English literature.PurposeWe describe two more cases that exhibited cervical myelopathy resulting from the combination of cervical OLF and OPLL and required surgery. A literature review with a comparative analysis between previous reports and present cases was also performed.Study designCase report and literature review.Patient sampleTwo patients with combined OLF and OPLL.Outcome measuresPreoperative computed tomography, magnetic resonance imaging, and pathological findings from operative specimens were used to confirm the diagnoses.MethodsA 76-year-old man (Case 1) presented with disturbance of gait and fine finger movement. Magnetic resonance imaging showed severe spinal canal stenosis and cord compression at the C3–C4 level. Computed tomography showed OPLL at the C2–C6 levels (segmental type) and OLF at the left C3–C4 level. The patient underwent posterior decompression and OLF resection. A 75-year-old man (Case 2) presented with sensory disturbance and muscle weakness in his bilateral upper extremities and disturbance in fine finger movements. Magnetic resonance imaging showed severe spinal canal stenosis and cord compression at the C2–C3 and C3 levels. Computed tomography showed OPLL at the C3–C7 levels (mixed type) and OLF at the left C2–C3 and C3 levels. The patient also underwent posterior decompression and OLF resection.ResultsIn both cases, histological examination of the surgical specimens showed osseous tissue and enchondral ossification within the ligamentum flavum, and the diagnosis in each case was OLF. After surgery, both patients' symptoms immediately improved, and no recurrence was observed at 2 years after surgery.ConclusionsWe experienced two cases of cervical myelopathy resulting from the combination of OLF and OPLL in the cervical spine. The symptoms of myelopathy were treated successfully by laminectomy and laminoplasty with OLF resection in both cases. The literature review including the present two cases revealed that cervical OLF tended to occur adjacent or close to the margin of cervical OPLL, suggesting that the increased mechanical stress at the junction of OPLL may be a causative factor.     

全椎板薄化层揭法治疗胸椎管狭窄症

目的 探讨采用全椎板薄化层揭法治疗由胸椎黄韧带骨化(ossification of ligamentum flavum,OLF)和胸椎后纵韧带骨化(ossification of posterior longimental ligament,OPLL)引起的胸椎管狭窄症的特点及疗效.方法 回顾121例胸椎管狭窄症患者的临床资料,男51例,女70例;年龄45～71岁,平均54.8岁;单纯胸椎OLF 72例,单纯胸椎OPLL 21例,合并胸椎OLF和OPLL 28例.对胸椎OLF和胸椎OPLL均采用全椎板薄化层揭法进行治疗.统计病变的节段与平面,测量椎体矢状位夹角,计算椎管面积残余率.采用日本骨科协会(Japanese Orthopaedic Association,JOA)评分系统对术前、术后脊髓功能进行评分并比较.结果 胸椎OLF的发病,下胸椎占77.0%(137/178);胸椎OPLL,上胸椎占81.1%(43/53).121例患者平均上胸椎后凸角31.5°±6.8°,下胸椎后凸角9.4°±3.5°.椎管面积残余率＞80%时,JOA评分从术前的(7.7±1.4)分提高到术后的(9.5±1.6)分;椎管面积残余率在80%～50%时,JOA评分从(5.2±1.8)分改善到(8.6±2.1)分;椎管面积残余率＜50%时,JOA评分从(4.8±1.4)分改善到(5.6±1.3)分.结论 胸椎OLF好发于下胸椎,胸椎OPLL好发于上胸椎.术前椎管面积残余率对预后有重要意义.只要临床症状和影像学表现相对应,应尽早手术,手术应尽量切除骨化物.胸椎管狭窄症术后易复发,再次手术更应注意减压范围和减压技巧.     

Involvement of Insulin-Like Growth Factor I in Development of Ossification of the Posterior Longitudinal Ligament of the Spine

In order to investigate the pathogenesis of ossification of the posterior longitudinal ligament (OPLL) of the spine, we examined the distribution of insulin-like growth factor I (IGF-I) in the posterior longitudinal ligaments of OPLL patients, and analyzed the effects of IGF-I on the cultured spinal ligament cells. For that purpose we established eight varieties of OPLL and non-OPLL cell lines obtained from spinal ligaments of corresponding patients, respectively. In contrast to non-OPLL cases, all the OPLL cases were histologically shown to contain round-shaped cartilage-like cells in the transitional region from preossifying to ossifying ligaments, and these cells were strongly stained with an antibody for IGF-I. In the vicinity of preossifying cartilaginous tissues, ligament cells also had a rod-like appearance and were positive for IGF-I immunohistochemically. The effects of IGF-I on cultured spinal ligament cells were assayed by alkaline phosphatase (AP) activity, DNA synthesis, and the amounts of collagen produced. The number of OPLL cell lines that increased AP activity, responding to IGF-I irrespective of 1,25(OH)₂D₃, was significantly larger than that of non-OPLL cell lines, although IGF-I stimulated DNA and procollagen type I carboxyl-terminal peptide synthesis in most of both OPLL and non-OPLL cell lines. These data demonstrate the dominant expression of IGF-I in the posterior longitudinal ligaments of OPLL patients, and suggest that IGF-I preferentially induces osteogenic differentiation in OPLL cells rather than in non-OPLL cells. IGF-I, therefore, may be involved in the local ossification process of spinal ligaments observed in OPLL patients. Received: 26 December 1996 / Accepted: 21 May 1997