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At least 19 recordsLinked to original sources
PubMed1993

Bone mineral density of the radius in patients with ossification of the cervical posterior longitudinal ligament. A longitudinal study.

Radial bone mineral density (BMD) in the distal one sixth and distal one third of the left radius was measured by single-photon absorptiometry (SPA) in patients with ossification of the cervical posterior longitudinal ligament (OPLL). Twenty-three OPLL patients (15 men and 8 women) with mean initial age of 60.1 years were studied longitudinally for mean follow-up period of 3.9 years. Based on roentgenologic findings, the patients were divided into two groups, those with advancing OPLL and those with non-advancing OPLL. The final value of distal 1/6th BMD in the advancing group was significantly lower than its initial value, but no change of the value of the distal 1/3rd BMD was observed in either group. The final value of distal 1/6th BMD/distal 1/3rd BMD ratio in the advancing group was significantly decreased compared with its initial value. These results suggest that, in the advancing OPLL group, trabecular bone mass decreased while cortical bone mass remained unchanged.

Absorptiometry, Photon↗
PubMed1994

[A radiographic study of the progression of ossification of the cervical posterior longitudinal ligament: the correlation between the ossification of the posterior longitudinal ligament and that of the anterior longitudinal ligament].

Progression of ossification of the posterior longitudinal ligament (OPLL) was evaluated in relation to that of ossification of the anterior longitudinal ligament (OALL). The subjects of this study were 68 patients with OPLL in the cervical spine. 47 of them underwent conservative treatment, and the remaining 21 underwent decompression surgery of the cervical spine (involving 11 cases of laminectomy and 10 of an enlargements of the spinal canal). All 68 patients were followed up for more than 5 years. Most of the continuous and most of the mixed types of OPLL exhibited advancement of the stage at the final examination, and showed much progression of OALL during the follow-up period. The progression of OALL tended to be more advanced in those cases in which the progression of OPLL was advanced. In most of the operated cases, OPLL was highly progressed after surgery in both the longitudinal direction and in the thickness, regardless of the ossification type. There was also evidence of progression of OALL in these patients, at each level of the cervical spine, with particularly advanced progression at the lower levels with a higher rate than in the conservative cases. These results indicate that the progressions of OPLL and OALL are closely correlated, and that the same precipitating factors may therefore be involved in both OPLL and OALL. A marked progression of the ossification after surgery suggested that local factors of the cervical spine played an important role in the progression.

Adult↗
PubMed2000

The superficial anulus fibrosus ligament. An incipient description of a separate ligament between the lumbar anterior longitudinal ligament and the intervertebral disc.

A previously unknown ligament, the superficial anulus fibrosus ligament (SAFL), situated on the ventral part of the L5 intervertebral disc (ID) was observed and described from autopsy material. Twenty-eight cadaveric specimens from 12 black and 16 white persons aged 17-30 years were studied during routine forensic autopsies. The anterior longitudinal ligament was separated from the ID and the ventral part of the SAFL was visualized. The SAFL samples were removed, measured and studied with both conventional histology and examination by transmission electron microscopy. The SAFL was a completely separate ligament at the level of the L5-S1 ID situated between the anterior longitudinal ligament and the anulus fibrosus of the ID. The fibers of the ligament were vertically oriented. A difference in distance between the L5-S1 vertebral bodies ventrally was noted in the two groups studied (18.7 +/- 1.2 mm in the black vs. 15.2 +/- 1.0 mm in the white, p < 0.001), indicating a difference in the ventral thickness of the intervertebral disc. Also, there was a difference in the length (black: 17.7 +/- 1.6 mm vs. white: 14.1 +/- 1.1), thickness (black: 3.3 +/- 0.3 mm vs. white: 2.1 +/- 1.9), and the cross-sectional area (black: 58.2 +/- 6.7 mm(2) vs. white: 26.5 +/- 2.7 mm(2), p < 0.001) of the SAFL. Conventional light microscopy revealed no obvious differences. However, transmission electron microscopy revealed notably larger collagen fibril diameter in black than white subjects. In conclusion, the interbody distances were greater in the black group, indicating a greater intervertebral disc thickness, compared to that of the white. Furthermore, the SAFL was significantly longer and thicker in the black than in the white group. Albeit unsubstantiated, these race-specific macroscopic findings may have implications for understanding the etiology of various low back stress problems.

Adolescent↗
PubMed1998

Proliferating cell nuclear antigen in hypertrophied spinal ligaments. Immunohistochemical localization of proliferating cell nuclear antigen in hypertrophied posterior longitudinal ligament of the cervical spine.

STUDY DESIGN: An experimental immunohistochemical investigation using an antibody for proliferating cell nuclear antigen. Surgically-extirpated specimens of posterior longitudinal ligament tissues from patients with hypertrophy of the posterior longitudinal ligament and other disorders of the cervical spine were analyzed. OBJECTIVE: To analyze the developmental mechanism of hypertrophy of the posterior longitudinal ligament, the authors evaluated the growth activity of cells in the posterior longitudinal ligament tissues by examining the immunolocalization of the proliferating cell nuclear antigen. SUMMARY OF BACKGROUND DATA: Although a number of cases of hypertrophy of the posterior longitudinal ligament have been reported, the pathophysiology of ligament hypertrophy is still unclear. It is well established that the proliferating cell nuclear antigen is a cell proliferation marker, and immunohistochemical analysis using an anti-proliferating cell nuclear antigen antibody is of value in assessing the cell growth activity of several tissues. METHODS: During anterior decompression surgery in the cervical spine, the authors extirpated posterior longitudinal ligament tissues in one piece from patients with hypertrophy of the posterior longitudinal ligament, ossification of the posterior longitudinal ligament, cervical disc herniation, and cervical spondylotic myelopathy. Midsagittal sections of the specimens were stained with an antibody against the proliferating cell nuclear antigen. RESULTS: In cases of hypertrophy of the posterior longitudinal ligament, immunostaining with the proliferating cell nuclear antigen was detected in cells in the posterior longitudinal ligament, not only at the vertebral endplate level, but also at the midvertebral level. A similar distribution of proliferating cell nuclear antigen-positive cells was observed in cases of ossification of the posterior longitudinal ligament. In cases of cervical disc herniation, however, proliferating cell nuclear antigen-positive cells in posterior longitudinal ligament tissues were restricted to the vertebral endplate level. No immunostaining with the proliferating cell nuclear antigen was seen in posterior longitudinal ligament tissues in cases of cervical spondylotic myelopathy. CONCLUSIONS: Cell growth activity was accelerated in posterior longitudinal ligament tissues in cases of hypertrophy of the posterior longitudinal ligament; such an unusual phenotype of posterior longitudinal ligament cells was also expressed in cases of ossification of cervical disc herniation and cervical spondylotic myelopathy. Therefore, up-regulation of the growth of posterior longitudinal ligament cells may contribute to the development of hypertrophy of the posterior longitudinal ligament, and some common regulatory mechanism(s) on the proliferation of posterior longitudinal ligament cells seem to underlie the development of hypertrophy of the posterior longitudinal ligament and ossification of the posterior longitudinal ligament.

Adult↗
PubMed2001

Quality of life in elderly patients with ossification of the posterior longitudinal ligament.

STUDY DESIGN: A longitudinal cohort study of 216 elderly patients with ossification of the posterior longitudinal ligament for an average of 13 years was performed. OBJECTIVE: To know the quality of life experienced by patients after treatment. SUMMARY OF BACKGROUND DATA: No report is available on the quality of life experienced by elderly patients with ossification of the posterior longitudinal ligament. Because the life prognosis of patients with this condition is relatively good, the quality of life experienced by elderly patients with this disease is an important subject. METHODS: The study participants were 216 elderly patients with ossification of the posterior longitudinal ligament. Conservative therapy was performed for 126 patients, and surgical therapy for 90 patients. Surgery was basically indicated for patients with myelopathy, who were classified using Nurick's grading system. The cumulative survival rate of these patients and their disabilities in daily living were reviewed. The occurrence of fracture resulting from osteoporosis was surveyed, and the relation of such fractures to bone mineral density was examined. RESULTS: The cumulative survival rate of 70-year-old patients exhibiting Nurick Grade 5 severe myelopathy before treatment was 20%, whereas that of patients without myelopathy or those with Grades 1, 2, 3, or 4 myelopathy before treatment was 80%. Patients who underwent surgical therapy for Grade 3 or 4 myelopathy were statistically more likely to be independent of assistance with activities of daily living than those with similar degrees of myelopathy who underwent conservative therapy. The final quality of life was poor for patients with Grade 5 myelopathy at the first examination, regardless of therapeutic method. The prevalence of complication by fracture in patients with ossification of the posterior longitudinal ligament was 1.4% for men and 8.6% for women. The bone mineral density in these patients without myelopathy was significantly higher than in healthy subjects of the same age. CONCLUSION: The study data suggest that surgical treatment should be chosen for patients exhibiting moderate myelopathy to obtain satisfactory quality of life for them over a long period.

Absorptiometry, Photon↗
PubMed2002

In vitro characteristics of cultured posterior longitudinal ligament tissue.

STUDY DESIGN: To determine the osteogenicity of posterior longitudinal ligament ossification, the posterior longitudinal ligament obtained during anterior cervical surgery from patients with the disorder was analyzed with in vitro cultures. OBJECTIVES: To determine the osteogenicity of the posterior longitudinal ligament. SUMMARY OF BACKGROUND DATA: The osteogenicity of posterior longitudinal ligament ossification in North America requires better documentation. METHODS: The posterior longitudinal ligament obtained during anterior cervical corpectomy with fusion from seven patients, three with ossification of the posterior longitudinal ligament documented by magnetic resonance imaging and computed tomography and four with spondylosis, was blindly submitted for in vitro culture. Explants of the posterior longitudinal ligament were placed in Dulbecco modified Eagle medium with 10% fetal calf serum, antibiotics, 4 mmol/L x L-proline, and 50 mg/L ascorbic acid. After reaching confluency, cells were trypsinized, and first-passage cells were used for all osteocalcin measurements to establish their osteoblastic phenotype. Periosteal cells, previously shown to synthesize osteocalcin, were used as a positive control. The cells were incubated with 1,25(OH)2 vitamin D3 at 10E-8 M for 72 hours in serum-free medium. The supernatants were collected and frozen, after which the quantity of osteocalcin induced by exposure to 1,25(OH)2 vitamin D3 was determined using enzyme-linked immunoassay. Control replicate cultures were measured without incubation using vitamin D3. RESULTS: Ossification of the posterior longitudinal ligament cell lines responded positively with osteocalcin synthesis in the 0.1 to 0.4 ng/M range. The cell line of the patient with spondylosis alone did not respond to vitamin D3 priming. CONCLUSIONS: Posterior longitudinal ligament cells from the three North American white patients with ossification of the posterior longitudinal ligament, when cultured in vitro, synthesized osteocalcin on vitamin D3 priming, confirming their osteoblastic phenotype, whereas posterior longitudinal ligament cells from four white patients with isolated spondylosis did not.

Calcitriol↗
PubMed1997

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.

Activin Receptors↗
PubMed1999

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.

Adult↗
PubMed1998

Quantitative anthropometry of the subatlantal cervical longitudinal ligaments.

STUDY DESIGN: The quantitative anthropometry of the cervical longitudinal ligaments was determined in 20 human cadaveric subatlantal cervical spines at the limits of flexion and extension. OBJECTIVES: To provide measurements of cervical anterior and posterior longitudinal ligament lengths, widths, and cross-sectional areas at segmental levels. SUMMARY OF BACKGROUND DATA: Although mathematical models of the cervical spine require specific data to predict kinematics, the anthropometry of the cervical spine has not been examined in detail. The dimensional changes of ligaments in physiologic motion are not well characterized. METHODS: Segmental lengths and widths of the cervical longitudinal ligaments were measured in sagittal plane flexion and extension, using a three-dimensional electromagnetic digitizer. The cross-sectional areas of the ligaments at resting length were measured with a laser micrometer system. Comparisons between anterior and posterior location and among segmental levels were made. Several ligaments were examined histologically to determine the insertion sites and, thus, to define the segmental length. RESULTS: The anterior longitudinal ligaments were shorter in flexion than in extension. In extension, they were longer than the posterior longitudinal ligaments in flexion. The resting isolated ligaments were longer than the longest in situ lengths at several vertebral levels. The anterior longitudinal ligaments were wider at the disc than at the body. The cross-sectional area at C2-C3 was smaller than at subaxial levels. The longitudinal ligaments were observed to insert along the entire underlying vertebral body. CONCLUSIONS: The quantitative anthropometry of the cervical longitudinal ligaments is important in the development of accurate mathematical models of the cervical spine. The in situ ligaments may not be under tension in the physiologic range of motion.

Aged↗
PubMed1997

Bone morphogenetic protein-2 stimulates differentiation of cultured spinal ligament cells from patients with ossification of the posterior longitudinal ligament.

Ossification of the posterior longitudinal ligament (OPLL) of the spine is characterized by heterotopic bone formation occurring in spinal ligament, causing severe compression myelopathy. In order to investigate the mechanism of OPLL development, we isolated spinal ligament cells from OPLL patients as well as non-OPLL patients, and established 10 OPLL cell lines and 7 non-OPLL cell lines, respectively. We analyzed the effects of bone morphogenetic protein-2 (BMP-2) on these cells with respect to alkaline phosphatase (AP) activity, DNA synthesis, and collagen production. BMP-2 caused a significant increase of AP activity in 4 OPLL cell lines, whereas the activity did not change in any non-OPLL cells. Among OPLL cells, BMP-2 stimulated DNA synthesis in four cell lines and procollagen type I carboxyl-terminal peptide (PICP) synthesis in five cell lines. Some non-OPLL cells also responded to BMP-2, as there was an increase of DNA synthesis in three cell lines and PICP synthesis in one cell line. These data collectively indicate that BMP-2 preferentially induces osteogenic differentiation in OPLL cells rather than in non-OPLL cells. OPLL cells, therefore, exhibit a different response to BMP-2 than non-OPLL cells, suggesting that the expression of BMP receptor(s) and/or the signal transduction initiated by BMP-2 in the spinal ligament cells of OPLL patients somewhat deviate from those in normal spinal ligament cells. Such abnormal characteristics of OPLL cells as described here provide some clues to the clarification of the pathogenesis of OPLL.

Alkaline Phosphatase↗
PubMed2001

Mechanosensitive afferent units in the lumbar posterior longitudinal ligament.

STUDY DESIGN: The mechanosensitive afferent units in the lumbar posterior longitudinal ligament were investigated in an animal model using an electrophysiologic technique. OBJECTIVES: The objectives of this study were to identify the mechanosensitive receptive fields in the lumbar posterior longitudinal ligament and to investigate their distribution and characteristics. SUMMARY OF BACKGROUND DATA: The lumbar posterior longitudinal ligament has a nerve network originating from the sinuvertebral nerve. These fibers are thin, and most of their terminals are free nerve endings. Some immunohistochemical studies have indicated that they are immunoreactive to calcitonin gene-related peptide and/or substance P, suggesting a nociceptive function. Most of these studies investigated morphologic aspects, and there have been few studies employing electrophysiologic techniques to examine mechanosensitive units. METHODS: We used 13 adult cats. They were anesthetized and then laminectomy was performed. The L5 and L6 dorsal rootlets were draped over a recording electrode. To investigate the receptive fields in the posterior longitudinal ligament, afferent impulses were evoked by mechanical stimulation with a glass probe. When the receptive fields were located, they were stimulated electrically to obtain conduction velocity and were stimulated with a set of 17 nylon filaments to determine their mechanical thresholds. RESULTS: Thirteen units were identified in the lumbar posterior longitudinal ligament. The majority of the units were located around the intervertebral disc level of the posterior longitudinal ligament. The mean mechanical threshold was 47.04 +/- 15.25 g. According to the conduction velocities of the units, 12 units were classified into Group III (0.5-2.5 m/sec) and one unit into Group IV (2.5-20 m/sec). CONCLUSION: Mechanosensitive units classified into Group III or Group IV and with a high mechanical threshold (>7.0 g) were thought to act as nociceptive units. All units identified in this study satisfied these criteria. Our result suggests that afferent fibers from the lumbar posterior longitudinal ligament have a principally nociceptive function.

Afferent Pathways↗
PubMed2001

Hypertrophy of the posterior longitudinal ligament is a prodromal condition to ossification: a cervical myelopathy case report.

STUDY DESIGN: A histopathologic examination of a specimen that showed hypertrophy of the posterior longitudinal ligament of the cervical spine. OBJECTIVES: To illustrate the possibility of hypertrophy of the posterior longitudinal ligament as a prodromal condition to ossification of the posterior longitudinal ligament. SUMMARY OF BACKGROUND DATA: Despite much study, the pathology of ossification of the posterior longitudinal ligament still remains unclear. Hypertrophic change often is seen in the part of the ossified ligament; however, there have been few histopathologic reports on hypertrophy of the posterior longitudinal ligament. Some reports have suggested that hypertrophy of the posterior longitudinal ligament is a prodrome of ossification of the posterior longitudinal ligament. METHODS: A 64-year-old man was admitted to the hospital because of gait disturbance and developed oliguria. In a plain radiograph, segmental ossification of the posterior longitudinal ligament was found at C4, C5, and C6. Computed tomograph myelogram revealed a soft tissue shadow, maximum 3.8 mm in diameter, on the dorsal side of the ossification of the posterior longitudinal ligament at C5 and C6. Magnetic resonance T1-weighted image (T1WI) showed an equivalent signal with the intervertebral disc on the dorsal side of ossification of the posterior longitudinal ligament. This lesion was enhanced with Gd-DTPA and confirmed as hypertrophy of the posterior longitudinal ligament. Cervical anterior decompression and fusion were performed using Yamaura's technique. The ossified and thickened lesion was elevated and removed en bloc. Then, hematoxylin-eosin and toluidine blue staining was performed to detect metachromasia. RESULTS: Macroscopic examination of the specimen revealed that soft tissue formation was connected with the C4-C5 intervertebral space and extended downward to C6-C7. Histopatholgically, collagen fibers were proliferating in the long-axis direction on both ventral and dorsal sides. This was surrounded by extended nucleus pulposus-like chondrocyte tissue, where endplate cartilage was detected around the C4 pedicle. Roux staining was low, and partial vascular and cellular infiltration was observed, although it was not marked. CONCLUSION: The herniated nucleus pulposus involving endplate cartilage from C4-C5 was limited to the superficial layer, and proliferation of nucleus pulposus-like chondrocytes occurred in the herniated tissue, where they might undergo a change in cell phenotype. The results of the present study support the hypothesis that hypertrophy of the posterior longitudinal ligament is a prodromal condition to ossification of the posterior longitudinal ligament.

Cervical Vertebrae↗
PubMed2003

Cervical disc replacement-porous coated motion prosthesis: a comparative biomechanical analysis showing the key role of the posterior longitudinal ligament.

STUDY DESIGN: Benchtop cadaveric biomechanical comparative testing and caprine animal model in vivo implantation. OBJECTIVE: To evaluate the role of the posterior longitudinal ligament in cervical arthroplasty and to understand the relative contribution of this ligament in nonfusion applications. SUMMARY OF BACKGROUND DATA: Rauschning refers to the posterior longitudinal ligament as "The Kleenex Ligament" due to its apparent anatomic insignificance. White and Panjabi found the posterior longitudinal ligament ranked only fourth in importance in tensile load-to-failure biomechanical testing. In the postoperative situation following anterior cervical diskectomy fusion, posterior longitudinal ligament integrity is overlooked by physicians because the entire disc space usually fuses into a homogeneous block of bone. PURPOSE: This biomechanical study was undertaken to determine the relative importance of the posterior longitudinal ligament following two different degrees of anterior decompression, anterior disc replacement, and anterior arthrodesis procedures. METHODS: A total of seven fresh frozen human cadaveric cervical spines (C3-C7) (mean age 68 +/- 19 years) were used for biomechanical testing. Each vertebra was equipped with three non-colinear light emitting diodes designed for detection by an optoelectronic motion measurement system (3020 Optotract System). To determine the multidirectional flexibility, six pure moments (flexion, extension, right + left lateral bending, right + left axial rotation) and axial compression were applied using a servohydraulic 858 Bionix testing device configured with a six-degree-of-freedom spine simulator. Range of motion was defined as the peak displacement from the initial neutral position to the maximum load, whereas the neutral zone represents the motion from the initial neutral position to the unloaded position at the beginning of the third cycle. Seven groups of (N = 7 each) constructs at C5-C6 were: 1) intact "native" C5-C6 level; 2) anterior diskectomy (posterior longitudinal ligament intact); 3) a Low Profile Porous Coated Motion cervical disc replacement; 4) posterior longitudinal ligament resected; 5) Porous Coated Motion cervical disc replacement fixed with anterior flanges and screws; 6) tricortical structural allograft; and 7) an anterior cervical translational plate + allograft. The caprine model was evaluated for suitability as an animal model with 12 goats undergoing C3-C4 anterior cervical Porous Coated Motion disc replacement. RESULTS: Group 2 (anterior diskectomy alone) was significantly more stable than Group 4 (anterior diskectomy + posterior longitudinal ligament resection) in flexion-extension, 18.7 +/- 4.76 degrees versus 24.8 +/- 4.42 degrees (P < 0.05) and in lateral bending, 5.9 +/- 1.79 degrees versus 10.7 +/- 2.8 degrees (P < 0.05). The comparison for the two conditions for axial rotation, 10.4 +/- 13.9 degrees versus 13.9 +/- 2.7 degrees, and axial compression, 1.19 +/-.98 degrees versus 1.52 +/- 1.14 degrees, showed the same trend. Twelve goats undergoing porous coated motion cervical disc replacement had no evidence of prosthesis loosening, neurologic complications, or experienced inflammatory reactions from particulate wear debris after 6 months of implantation. DISCUSSION: This study confirms the pivotal role of the posterior longitudinal ligament in postsurgical stability of the cervical spine following anterior diskectomy. This is because the lateral anulus, uncovertebral ligaments, and lateral capsular ligaments are stretched and plastically deformed in the surgical distraction process of restoring the disc space height following anterior surgical decompression. There should be a separate determination of the range of motion of cervical disc replacements depending of the integrity and the amount of the posterior longitudinal ligament that has been resected. CLINICAL RELEVANCE: There are two basic types of total knee replacements, posterior cruciate ligament-preserving and posterior cruciate ligament-sacrificing designs. In the cervical spine, an analogous situation exists biomechanically depending on whether the posterior longitudinal ligament needs to be removed in its entirety as part of the spinal cord decompression part of the procedure--it may be helpful to conceptually differentiate between posterior longitudinal ligament-preserving and posterior longitudinal ligament-sacrificing total cervical disc replacements.

Aged↗
PubMed2001

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.

Adult↗
PubMed2003

Uniaxial cyclic stretch induces osteogenic differentiation and synthesis of bone morphogenetic proteins of spinal ligament cells derived from patients with ossification of the posterior longitudinal ligaments.

Ossification of the posterior longitudinal ligament of the spine (OPLL) is characterized by ectopic bone formation in the spinal ligaments. Mechanical stress, which acts on the posterior ligaments, is thought to be an important factor in the progression of OPLL. To elucidate this mechanism, we investigated the effects of in vitro sinusoidal cyclic stretch (120% peak to peak, at 1 Hz) on cultured spinal ligament cells derived from OPLL and non-OPLL patients. The mRNA expressions of alkaline phosphatase (ALP), osteopontin, bone morphogenetic protein (BMP)-2, BMP-4, and BMP receptors as well as ALP activity in cell layers and production of BMPs into the conditioned medium were significantly increased by cyclic stretch in OPLL cells, whereas no change was observed in non-OPLL cells. A stretch-activated Ca(2+) channel blocker, Gd(3+), the voltage-dependent L-type Ca(2+) channel blockers diltiazem and nifedipine, and Ca(2+)-free medium suppressed stretch-induced ALP activity, which suggests a role of Ca(2+) influx in the signal transduction of mechanical stress to the osteogenic response of OPLL cells. Our study provides first evidences that mechanical stress plays a key role in the progression of OPLL through the induction of osteogenic differentiation in spinal ligament cells and the promotion of the autocrine/paracrine mechanism of BMPs in this lesion.

Alkaline Phosphatase↗
PubMed1983

[Histopathological study of aging of the posterior portion of human cervical vertebral bodies and discs--with special reference to the early ossification of the posterior longitudinal ligament].

UNLABELLED: Ossification of the posterior longitudinal ligament ( OPLL ) of the cervical spine is a disease causing spinal canal stenosis and, henceforth , spinal cord compression. This ossification is found approximately in three percent of the adult Japanese, but it is also found to be present among Chinese, Korean and other South-East Asians, whereas the incidence among Caucasians was reported to be significantly low. The etiology of this interesting ossification is still unknown although multidisciplinary studies have been carried out in Japan in recent years. The purpose of the present study is to find an early ossification of the posterior longitudinal ligament of the cervical spine and to see its relationship with other chronological changes of the surrounding structures. MATERIAL AND METHOD: One hundred and forty-one cervical spinal columns were obtained en bloc from C2 to C7 from the autopsied bodies at Juntendo University Hospital and at the Tokyo Metropolitan Medical Examiners' Office. There were 89 males and 52 females with a wide age distribution. A 66 year-old male case with advanced continuous OPLL died at Juntendo University Hospital was added to the study. The specimens were either cross-sectioned or sagittally sectioned, and studied soft-ray-roentgenologically and histopathologically. RESULTS: There were specimens after the third decade of life showing micro-ossification along the midline of the posterior aspect of the vertebral body on cross-section as well as micro-ossification or hyperostosis adjacent to the posterior corner of the vertebral body on sagittal section. These micro-ossification or hyperostosis seemed to be a product of a physiological aging process, but could be considered as a precursor of the OPLL . The periosteum was well demonstrated on the posterior aspect of the vertebral body in the first two decades of life, but it became inconspicuous with age. In the adult spine there was no clear delineation between the deep layer of the posterior longitudinal ligament and the fibrous layer of the periosteum . The cambium layer looked absent on hematoxylin-eosin stain. However, on Giemsa stain there appeared a thin layer which would present increased cellular activity between the body and what appeared to be the fibrous layer of the periosteal. This layer was considered to be a 'sleeping cambium layer' for which it was named 'latent periostium layer (LPL)'.(ABSTRACT TRUNCATED AT 400 WORDS)

Adolescent↗
PubMed2003

Role of prostaglandin I2 in the gene expression induced by mechanical stress in spinal ligament cells derived from patients with ossification of the posterior longitudinal ligament.

Ossification of the posterior longitudinal ligament of the spine (OPLL) is characterized by ectopic bone formation in the spinal ligaments, and mechanical stress has been suggested to play an important role in the progression of OPLL. To identify the genes that participate in OPLL, the differential display reverse transcription-polymerase chain reaction (RT-PCR) method was used. A 283-base pair cDNA fragment corresponding to prostaglandin I2 (PGI2) synthase was highly expressed in OPLL cells compared with non-OPLL cells. To examine the effect of mechanical stress on the expression of PGI2 synthase, cells were subjected to uniaxial cyclic stretch (0.5 Hz, 20% stretch), and PGI2 synthase mRNA expression was assessed by quantitative RT-PCR. Cyclic stretch induced an increase in PGI2 synthase in OPLL cells in a time-dependent manner, whereas no change was observed in non-OPLL cells. Cyclic stretch for 9 h also induced a 2.86x increase in PGI2 production. Beraprost (a stable PGI2 analog) and dibutyryl cAMP (a membrane-permeable cAMP analog) increased the mRNA expression of alkaline phosphatase (ALP) as a marker for osteogenic differentiation up to 240 and 200%, respectively, in OPLL cells, whereas no change was observed in non-OPLL cells. The increases in ALP mRNA induced by beraprost and cyclic stretch were both inhibited by SQ22536, a potent adenylate cyclase inhibitor. These data suggest that the increase in PGI2 synthase induced by mechanical stress plays a key role in the progression of OPLL, at least in part through the induction of osteogenic differentiation in spinal ligament cells via the PGI2/cAMP system.

Adenylyl Cyclase Inhibitors↗
PubMed2003

Uni-axial cyclic stretch induces Cbfa1 expression in spinal ligament cells derived from patients with ossification of the posterior longitudinal ligament.

Ossification of the posterior longitudinal ligament of the spine (OPLL) is characterized by ectopic bone formation in the spinal ligaments. Mechanical stress, which acts on the posterior ligaments, is thought to be an important factor in the progression of OPLL. To clarify this mechanism, we investigated the effects of in vitro cyclic stretch (120% peak to peak, at 0.5 Hz) on cultured spinal ligament cells derived from OPLL (OPLL cells) and non-OPLL (non-OPLL cells) patients. The mRNA expressions of Cbfa1 (an osteoblast-specific transcription factor), type I collagen, alkaline phosphatase (ALP), osteocalcin and integrin beta1 (a mechanotransducer) were increased by cyclic stretch in OPLL cells, whereas no change was observed in non-OPLL cells. The effects of cyclic stretch on the spinal ligament tissues derived from OPLL and non-OPLL patients were also analyzed by immunohistochemistry using an antibody against Cbfa1. The expression of Cbfa1 was increased by cyclic stretch at the center of the spinal ligament tissues of OPLL patients, whereas no change was observed in the tissues of non-OPLL patients. Furthermore, U0126, a specific inhibitor of MAPK kinase (MEK), suppressed the stretch-induced mRNA expressions of Cbfa1, ALP and type I collagen in OPLL cells. These results suggest that in OPLL cells, mechanical stress is converted by integrin beta1 into intracellular signaling and that Cbfa1 is activated through the MAP kinase pathway. Therefore, we propose that mechanical stress plays a key role in the progression of OPLL through an increase in Cbfa1 expression.

Aged↗