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.     

Total (anterior and posterior) decompression of the spinal cord: surgical treatment for combined ossification of the posterior longitudinal ligament and yellow ligament of the thoracic spine

The ossification of the posterior longitudinal ligament (OPLL) combined with ossification of the yellow ligament (OYL) in the thoracic spine can compress the spinal cord from the anterior and posterior direction, resulting in serious myelopathy. For these cases we devised a treatment consisting of two steps, total decompression of the spinal cord. The first step is removal of ossified yellow ligament posteriorly following wide laminectomy and the second step is removal of ossified posterior longitudinal ligament anteriorly, followed by interbody fusion. As the final procedure of the first step, two parallel deep gutters, covering the complete length of the ossified ligament to be removed anteriorly, are drilled from the posterior direction into the vertebral body along both sides of the dura. This pretreatment makes removal of the ossified ligament from the anterior, during the second stage, much easier and safer. This operation appears to be a promising operative procedure from our seven case experiences so far.     

Experimental study on ossification of spinal ligaments in the rabbit under influence of bone morphogenetic protein

Bone morphogenetic protein (BMP) is known to induce cartilage from mesenchymal cells in organ culture. The purpose of the present study was to determine whether spinal ligaments differentiate into cartilage when cultured with BMP. Implantation of BMP into the yellow ligament was also done to make a model of the ossification of yellow ligament. The rabbit was employed as an experimental animal. In organ culture, BMP induced new cartilage from the posterior longitudinal ligament, the yellow ligament and the supraspinous ligament. This indicates that spinal ligaments have the potential to ossify, and bone or periosteum may not have a direct relationship with spinal ligament ossification. Ossification of the yellow ligament was produced by implantation of BMP. Blood vessels are thought to have some role in the ossification of spinal ligaments. The spinal cord was compressed posteriorly by the ossified yellow ligament. This ossification of the yellow ligament resembled that of human beings and may be regarded as a useful experimental model.     

Orthotopic ossification of the spinal ligaments of zucker fatty rats: A possible animal model for ossification of the human posterior longitudinal ligament

Ossification of the posterior longitudinal ligament is a human genetic disease in which pathological ectopic ossification of the spinal ligaments develops. This leads to myelopathy or radiculopathy due to compression of the spinal cord. In this study, we investigated the histological features of orthotopic ossification of the spinal ligaments of senile Zucker fatty rats. A remarkably high incidence of orthotopic ossification was observed mainly in the thoracic spinal ligaments as compared with controls. The histopathological findings were similar to those for ossification of the human posterior longitudinal ligament. Bone morphogenetic proteins and activins, which exert their effects by way of specific type-I and type-II serine/threonine kinase receptors, play important roles in the formation of bone and cartilage. In the spinal ligaments of Zucker fatty rats, bone morphogenetic protein receptors and activin receptors were immunohistochemically detected around the ossified foci in a manner similar to that previously shown for the ossified tissue from patients who had ossification of the posterior longitudinal ligament. Thus, bone morphogenetic proteins and activin receptors might play important roles in orthotopic ossification of the spinal ligaments of Zucker fatty rats as well as in ossification of the posterior longitudinal ligament of humans. In addition, bone morphogenetic protein-receptor-IA was expressed in the nonossified ligament, suggesting that the spinal ligaments of the rats may have a predisposition to orthotopic ossification. In the controls, no expression of bone morphogenetic protein receptors or of activin receptors was observed. In conclusion, there is a great degree of similarity between orthotopic ossification of the spinal ligaments of Zucker fatty rats and ossification of the posterior longitudinal ligament of humans. Thus, the rats provide a useful animal model for the study of ossification of the human posterior longitudinal ligament.     

Surgical treatment of lumbar ossification of the posterior longitudinal ligament. Report of two cases and description of surgical technique

The authors report two cases of patients with lumbar ossification of the posterior longitudinal ligament (OPLL). One patient underwent surgery via the single posterior approach, and the other patient underwent combined anterior-posterior surgery. The authors consider the anterior approach for excision of the ossified lesion to be the most reasonable for treatment of lumbar OPLL. It is extremely important, however, to select the surgical procedure according to the individual patient's condition.     

A case of ossified yellow ligaments (ossified ligamenta flava) of the thoraco-lumbar region and magnetic resonance imaging

A Case of ossified yellow ligaments in thoraco-lumbar region is reported. A 47-year-old-male complained low back pain with suddenness in August, 1984. One month later, he noticed dyesthesia on his right lower extremity and gait disturbance. These symptoms progressed slowly. In June, 1985, he admitted to The Jikei University Hospital. On neurological examinations, he was noticed an intermittent claudication, spastic paraparesis and stocking type sensory loss in his lower extremities. Plain lumbar X-ray films showed ossified yellow ligaments (OYL) in the posterior half of the spinal canal from the level of 10th thoracic to second lumbar vertebrae. Magnetic resonance imaging disclosed marked indentations of the spinal cord at the same level. The wide laminectomy was carried out and OYL were removed totally in gentle manner. Postoperative course was uneventful. His sensory disorders improved remarkably and he gained good muscle strength in his lower extremities, but a considerable spasticity remained still. OYL is closely related to the developmental canal stenosis, the spondylosis and the other degenerative disorders such as ossification of posterior longitudinal ligaments. This allows more complicated neurological signs and symptoms in the case of OYL. When OYL is suggested, it is recommended to performed whole spinal radiological survey. The surgical consideration should be done. From this point of view, MRI would be a most useful weapon.     

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.     

Degeneration and ossification of the yellow ligament in unstable spine.

Lumbar yellow ligaments were obtained from 20 cases of lumbar spinal canal stenosis and 20 cases of degenerative olisthesis with slippage of more than 3 mm. The ligaments were stained with safranin-O, von Kossa, and immunohistochemical staining methods (S-100 protein). In the unstable group the safranin-O staining was more intense, microscopic ossification and chondroblasts were noted more frequently, and S-100 protein was more abundant. These findings show that instability of the lumbar spine accelerates degeneration and chondrometaplasia of the yellow ligament, which may lead to the enchondral ossification of the ligament.     

Postoperative cerebrospinal-fluid fistula associated with erosion of the dura. Findings after anterior resection of ossification of the posterior longitudinal ligament in the cervical spine.

Of twenty-two patients who had had anterior decompression of the spinal canal for ossification of the posterior longitudinal ligament and cervical myelopathy, seven had absence of the dura adjacent to the ossified part of the ligament. The spinal cord and nerve-roots were visible through this defect. Although the arachnoid membrane appeared to be intact and watertight in most patients, a cerebrospinal-fluid fistula developed postoperatively in five, and three had a second operation to repair the defect in the dura. On the basis of this experience, we recommend use of autogenous muscle or fascial dural patches, immediate lumbar subarachnoid shunting, and modification of the usual postoperative regimen, such as limitation of mechanical pulmonary ventilation to the shortest time that is safely possible and use of anti-emetic and antitussive medications to protect the remaining coverings of the spinal cord when the dura is found to be absent adjacent to an ossified portion of the posterior longitudinal ligament in the cervical spine.     

Hyperostotic lumbar spinal stenosis. A review of 12 surgically treated cases with roentgenographic survey of ossification of the yellow ligament at the lumbar spine

Although there is considerable literature concerning ossification of the posterior longitudinal ligament or the ligamentous flava (OPLL or OYL) in the cervical and thoracic spine, there are only a few references about OPLL or OYL in the lumbar spine. The authors have described lumbar spinal stenosis due to OPLL or OYL as hyperostotic lumbar spinal stenosis, and analyzed 12 surgically documented cases with this condition. The symptoms and signs of hyperostotic lumbar spinal stenosis are the same as those seen in degenerative lumbar spinal stenosis, but the degree of paraparesis is much more severe in hyperostotic lumbar spinal stenosis. Computed tomography scan imaging clearly demonstrates OPLL or OYL in the lumbar spine, although some lesions can be seen on the lateral view of a plain roentgenogram. The results of 12 surgical cases suggest that decompression laminectomy produces relief of symptoms. An analysis of 2,403 plain lumbar roentgenograms showed an incidence of 8.4% OYL in the lumbar spine, with frequent involvement of the upper and middle lumbar spine. A classification system of OYL in the lumbar spine has been developed. The entire spine should be examined before surgery on a patient with hyperostotic lumbar spinal stenosis because of a tendency to ossify spinal ligaments at other levels.     

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.     

Stenosis of the lumbar spinal canal in vertebral ankylosing hyperostosis.

Certain morphologic features frequently observed in radiography or computed tomography (CT) scan in patients with hyperostosis led us to study the association between a narrowed spinal canal and vertebral hyperostosis. Twenty-eight items were selected and studied by three different investigators (two rheumatologists and one radiologist) in radiographs and CT scans of 100 patients with acquired stenosis of the lumbar canal, with or without hyperostosis (46 and 54 cases, respectively). The most distinctive points that we suggest can be used as diagnostic criteria of the hyperostotic narrowed lumbar canal are anterior or posterior lateral marginal somatic osseous proliferations, proliferations of the nonarticular aspects of the posterior apophyses, and ossifications of the posterior articular capsule and of the ligaments (yellow ligament, posterior longitudinal ligament, and the supraspinal ligament). Four of these six criteria should be present to establish the diagnosis of hyperostotic lumbar stenosis. The appearance of lumbar hyperostosis on X-ray or CT scans differs from that of simple degenerative changes due to arthrosis, and the hyperostosis can be held responsible for dural compression.     

Study of the innervation of the spinal ligaments at the lumbar level

The authors studied the innervation of the human lumbar spinal ligaments on cadaver or surgical specimens. In the ligaments annexed to the neural arch and in the posterior longitudinal ligament were found free-ending fibers and amyelinic perivascular fibers. In the anterior longitudinal ligament, coexisting with perivascular fibers were found encapsulated corpuscular formations on the ventrolateral aspect of the junction between the intervertebral disc and vertebral body. These findings comfort the role of the anterior longitudinal ligament in proprioception essential both in static and dynamic function of the spine.     

Lateral rhachotomy for thoracic spinal lesions

Capener's "Lateral Rhachotomy" was modified by additional excision of the pedicle, articular facets, part of the lamina, and a posterior half of the vertebral bodies on one side through a transpleural approach to the thoracic spine, and a retroperitoneal approach to the lumbar spine. The aim was to excise a space-occupying lesion, which exists in front of the thoracic or lumbar spinal cord, safely. This modification enable the authors to expose more than 50% of the spinal canal, and decompress it from its anterior, lateral, and posterior compressing mass. The utmost important point of this procedure is the excision of the lesion under the direct visualization of the dura. In ossification of the posterior longitudinal ligament (OPLL), the dura is usually indented by the thick bony mass, and the lesion extends over a few segment with adhesion. Using "Modified Lateral Rhachotomy," it was possible to explore three or four vertebral levels in continuity through the same skin incision. In the present report, the authors described their "Modified Lateral Rhachotomy" procedure, and reviewed the case material.     

Management of cervical myelopathy due to ossification of posterior longitudinal ligament in a patient with Alstr?m syndrome

Introduction

Alström syndrome (AS) is a rare autosomal recessive genetic disorder with multisystemic involvement characterised by early blindness, hearing loss, obesity, insulin resistance, diabetes mellitus, dilated cardiomyopathy, and progressive hepatic and renal dysfunction. The clinical features, time of onset and severity can vary greatly among different patients. Many of the phenotypes are often not present in infancy but develop throughout childhood and adolescence. Recessively inherited mutations in ALMS1 gene are considered to be responsible for the causation of AS. Musculoskeletal manifestations including scoliosis and kyphosis have been previously described.

Case report

Here, we present a patient with AS who presented with cervical myelopathy due to extensive flowing ossification of the anterior and posterior longitudinal ligaments of the cervical spine resulting in cervical spinal cord compression. The presence of an auto-fused spine in an acceptable sagittal alignment, in the background of a constellation of medical comorbidities, which necessitated a less morbid surgical approach, favored a posterior cervical laminectomy decompression in this patient. Postoperatively, the patient showed significant neurological recovery with improved function. Follow-up MRI showed substantial enlargement of the spinal canal with improved space available for the spinal cord. The rarity of the syndrome, cervical myelopathy due to ossified posterior longitudinal ligament as a disease phenotype and the treatment considerations for performing a posterior cervical decompression have been discussed in this Grand Rounds’ case presentation.     

Clinical analysis of ossified thoracic ligaments and thoracic disc hernia]

Thoracic lesions present several clinical problems, particularly in their diagnosis and treatment, compared with cervical or lumbar lesions. Since 1983, 18 cases of thoracic space lesions, excluding spinal tumors or trauma have been experienced: nine cases of ossification of yellow ligament (OYL), five of ossification of posterior longitudinal ligament (OPLL), and four of disc hernia (DH). In these 18 patients, problems of clinical manifestations, neuroradiological examination, and surgical approaches are analyzed and discussed. As clinical manifestations, there was a preponderant occurrence in males in the OYL group, while in the OPLL group all the patients were females. OYL and DH occurred at lower thoracic levels. Thirteen of the 18 patients showed combined lesions either in the cervical or in the lumbar regions, such as cervical OPLL, cervical spondylosis, lumbar DH, and lumbar canal stenosis. In the neuroradiological examinations diagnosis of the upper thoracic lesions was difficult. Computed tomography (CT) scan with intrathecal metrizamide injection seemed essential for examination of ossified thoracic lesions. However, because CT imaging of the entire spine is impractical, efficient use of this examination requires previous localization of the offending vertebral level from either the neurological findings or other neuroradiological examinations such as myelography. Magnetic resonance imaging seemed most useful for ruling out the thoracic compressing lesions. As for surgical approaches, posterior decompression was effective for OYL and the anterior approach was useful for OPLL and DH. In patients with "tandem lesions," neurological and neuroradiological findings played an important role in deciding the responsible site.     

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     

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.     

Computer-assisted measurement of the size of ossification in patients with ossification of the posterior longitudinal ligament in the cervical spine

Background Progression of ossification of the posterior longitudinal ligament in patients may lead to serious neurological deterioration. A government-funded study group established a manual method of measurement on plain radiographs to detect progression of the ossified lesion. However, this method did not gain wide acceptance because it was time-consuming and complicated, for which drawings of many lines and points are required. We have applied a computer-assisted measurement system to this task and have evaluated inter- and intraexaminer reliability, showing that it is quicker to use and more accurate than the manual method. Methods Eight board-certified spine surgeons, acting as the examiners, measured the sizes of the ossified lesions on nine lateral cervical spine radiographs using the computer-assisted measurement system. Following insertion of digitized radiographic image data into a computer, the corners of the vertebral bodies on the displayed images are marked by the examiners, and the software automatically sets reference lines and points. The examiners identify upper, lower, and posterior margins of the ossified lesions, and the software calculates the dimensions of the ossified lesions. Data obtained from eight examiners for length and thickness underwent rigorous statistical analysis by calculating the intraclass correlation coefficients with 95% confidence intervals (CIs) to determine interexaminer reliability and Pearson's correlation coefficients between the two measurements by the same examiner to determine intraexaminer reliability. Results The intraclass correlation coefficients were 0.927 and 0.968 with 95% CIs of 0.883–0.955 and 0.956–0.978 for measurements of length and thickness, respectively, of the ossified lesions. The Pearson's correlation coefficients for the two measurements by the same examiners were 0.943–0.985 for length and 0.957–0.991 for thickness. Conclusions The inter- and intraexaminer reliability using this measurement system was excellent. The method can detect progression of ossification of the posterior longitudinal ligament (OPLL) on plain radiographs with high precision and could become a standard method for measuring the size of OPLL.     

Immunohistochemical localization of types I,II, and III collagens in the ossified posterior longitudinal ligament of the human cervical spine

Summary Immunohistochemical localization of types I, II, and III collagen in the ossified posterior longitudinal ligament of the cervical spine was studied using type-specific anticollagen antibodies. In contrast to the normal ligament which contains both types I and III collagens, the ossified matrix, composed of lamellar bone, contains only type I collagen, except for Haversian canals where type III is located in the inner wall. In the transitional region of preossifying ligaments, types III and I are both present. Type II collagen is present in the hyperplastic matrix of the ligament, and cartilage-like cells surrounded by type II collagen are aligned along nonossified ligaments adjacent to the preossifying region. A possible mechanism of matrix transition during the ossification process is given attention.