Eiji Taketomi

Interobserver and intraobserver reliability of the japanese orthopaedic association scoring system for evaluation of cervical compression myelopathy.

Study Design. The inter- and intraobserver reliabilities of an assessment scale for cervical compression myelopathy were examined statistically. This scoring system consists of seven categories: motor function of fingers, shoulder and elbow, and lower extremity; sensory function of upper extremity, trunk and lower extremity; and function of the bladder. It evaluates the severity of myelopathy by allocating points based on degree of dysfunction in each category. Objectives. To determine the inter- and intraobserver reliabilities of the revised scoring system (17 − 2 points) for cervical compression myelopathy proposed by the Japanese Orthopedic Association. Summary of Background Data. Several scales to assess clinical outcome from treatment of cervical compression myelopathy have been proposed. Most of these scales include items evaluated by observers. However, no system, including the Japanese Orthopedic Association scoring system, has yet been validated in terms of interobserver reliability. Methods. From five different university hospitals, 10 spine surgery specialists, 10 orthopedic surgeons who had just passed the board examination of the Japanese Orthopedic Association, and 13 residents in the first or second year of orthopedic residency programs were chosen. The participants in this study were 29 patients with myelopathy secondary to ossification of the posterior longitudinal ligament selected from five participating university hospitals. Several surgeons interviewed each patient twice at intervals of 1 to 6 weeks. Inter- and intraobserver reliabilities of the total score for all categories were evaluated by the intraclass correlation coefficient. The extension of the kappa coefficient of Kraemer also was calculated for each category to assess reliability of multivariate categorical data. Results. The interobserver reliability of the total score for the first interview (intraclass correlation coefficient = 0.813) and the intra- and interobserver reliabilities of the total score (intraclass correlation coefficient = 0.826) were high. The level of experience and the hospital slightly affected the reliability of the Japanese Orthopedic Association scoring system. The kappa values for intraobserver data generally were high in each category, whereasthe kappa values for interobserver data were relatively low for the categories of shoulder–elbow motor function and lower extremity sensory function. Conclusions. The inter- and intraobserver reliabilities of the Japanese Orthopedic Association scoring system for cervical myelopathy were high, suggesting that this system is useful for assessment of cervical myelopathy in comparative studies of treatment.

Genetic mapping of ossification of the posterior longitudinal ligament of the spine.

Ossification of the posterior longitudinal ligament of the spine (OPLL) is recognized as a common disorder among Japanese and throughout Asia. Estimates of its prevalence are in the range of 1. 9%-4.3%. Although its etiology is thought to involve a multiplicity of factors, epidemiological and family studies strongly implicate genetic susceptibility in the pathogenesis of OPLL. In this study we report an identification of a predisposing locus for OPLL, on chromosome 6p, close to the HLA complex. The evidence for this localization is provided by a genetic-linkage study of 91 affected sib pairs from 53 Japanese families. In this sib-pair study, D6S276, a marker lying close to the HLA complex, gives evidence for strongly significant linkage (P = .000006) to the OPLL locus. A candidate gene in the region, that for collagen 11A2, was analyzed for the presence of molecular variants in affected probands. Of 19 distinct variants identified, 4 showed strong statistical associations with OPLL (highest P = .0004). These observations of linkage and association, taken together, show that a genetic locus for OPLL lies close to the HLA region, on chromosome 6p.

Genetic study of ossification of the posterior longitudinal ligament in the cervical spine with human leukocyte antigen haplotype.

To evaluate the genetic background of ossification of the posterior longitudinal ligament, the relationship between the presence or absence of ossification and human leukocyte antigen haplotypes was studied in 33 families of patients with ossification of the posterior longitudinal ligament. The study revealed that human leukocyte antigen haplotypes formed certain types of clusters, and that some human leukocyte antigen haplotypes were very rare in the Japanese population, suggesting the involvement of human leukocyte antigen-linked factors in the pathogenesis of ossification of the posterior longitudinal ligament of the cervical spine. In the families of these patients, ossification of the posterior longitudinal ligament was demonstrated by radiography in 56% (10/18) of the siblings. Each of these siblings shared both human leukocyte antigen haplotypes with the patient. None of those who shared only one human leukocyte antigen haplotype with the patient had developed ossification of the posterior longitudinal ligament. From these findings, the presence of both pathogenic human leukocyte antigen haplotypes is considered to be necessary for the development of ossification of the posterior longitudinal ligament, and this genetic predisposition may be activated by multiple factors, including regressive degeneration due to aging and the environment.

The natural course of myelopathy caused by ossification of the posterior longitudinal ligament in the cervical spine.

The natural course of ossification of the posterior longitudinal ligament, particularly the relationship between the onset of myelopathy and factors associated with its aggravation, was studied in 207 patients during an average period of 10 years 3 months. Myelopathic signs were already present in 37 (18%) patients at the time of the initial examination. Fourteen of these 37 patients showed aggravation of symptoms during the observation period. Myelopathy appeared during the observation period in 33 (16%) of the 207 patients. One hundred thirty-seven (66%) patients were free of myelopathy. Some patients had no myelopathic signs, despite severe spinal stenosis, because of the ossification. In these patients, the range of motion of the cervical spine was severely limited, indicating that dynamic factors are important in the development of myelopathy. In treating this disease, it is necessary to take into consideration the natural course of the disease and to identify the involvement not only of static factors, such as compression caused by ossification, but also of dynamic factors.

Prognosis of Patients With Upper Cervical Lesions Caused by Rheumatoid Arthritis : Comparison of Occipitocervical Fusion Between C1 Laminectomy and Nonsurgical Management

Study Design. A matched controlled comparative study of patients with upper cervical lesions caused by rheumatoid arthritis was performed at two different hospitals to evaluate occipitocervical fusion associated with C1 laminectomy and nonsurgical treatment. Objectives. To evaluate the long-term results and advantages of occipitocervical fusion associated with C1 laminectomy, and to compare these results with those of nonsurgical management of patients with myelopathy related to rheumatoid arthritis. Summary of Background Data. Few studies have reported the prognosis of patients with rheumatoid arthritis managed by occipitocervical fusion associated with C1 laminectomy. Methods. In this study, 40 patients with rheumatoid arthritis and myelopathy caused by irreducible atlantoaxial dislocation with or without upward migration of the odontoid process were studied. Of these 40 patients, 19 were treated by occipitocervical fusion using a rectangular rod associated with C1 laminectomy at one hospital, whereas 21 matched patients were treated conservatively at another hospital. The patients were observed by the same protocol to assess the radiologic and clinical results, including functional recovery and survival rate. All the patients were followed until their death. Results. The atlantodental interval was reduced immediately after surgery, and this result had been well maintained at the final follow-up assessment. Redlund-Johnell values did not vary significantly throughout the course of the study. As for neural assessment with the Ranawat classification system, improvement was found in 13 (68%) of the 19 patients who underwent surgery. The survival rate was 84% 5 years after surgery, and 37% in the first 10 years. In the patients who did not undergo surgical treatment, atlantodental interval and Redlund- Johnell values were aggravated. These patients showed no neural improvement, and aggravation was found in 16 (76%) of the 21 cases during the follow-up period. All the patients were bedridden within 3 years after the onset of myelopathy. The survival rate was 0% in the first 8 years. Conclusions. The findings lead to the conclusion that occipitocervical fusion associated with C1 laminectomy for patients with rheumatoid arthritis is useful for decreasing nuchal pain, reducing myelopathy, and improving prognosis.

Functional impact of human collagen α2 (XI) gene polymorphism in pathogenesis of ossification of the posterior longitudinal ligament of the spine

Ossification of the posterior longitudinal ligament (OPLL) of the spine is the leading cause of myelopathy in Japan. In earlier studies, we provided genetic linkage and allelic association evidence of distinct differences in the human collagen α2(XI) gene (COL11A2) that might constitute inherited predisposition to OPLL.(1) In the present study, a strong allelic association with non‐OPLL (p = 0.0003) was observed with an intron 6 polymorphism [intron 6 (−4A)], in which the intron 6 (−4A) allele is more frequently observed in non‐OPLL subjects than in OPLL patients. In addition, a newly identified polymorphism in exon 6 [exon 6 (+28A)] was in linkage disequilibrium with the intron 6 (−4A). The functional impact of the polymorphisms was analyzed by comparing the differences in messenger RNA (mRNA) splicing by reverse‐transcription polymerase chain reaction (RT‐PCR) analysis in cultured cells from the interspinous ligament and an in vitro exon trapping study. The intron 6 (−4A) allele resulted in skipping exon 6 and retaining exon 7, while the exon 6 (+28A) allele was not associated with alteration in mRNA splicing. Similar mRNA species were observed in undifferentiated osteoblast (Ob) cells and in cells from posterior longitudinal ligament of non‐OPLL subjects. The region containing exons 6‐8 is an acidic subdomain presumably exposed to the surface that could interact with molecules of the extracellular matrix. Accordingly, retaining exon 7 together with removal of exon 6 observed in intron 6 (−4A) could play a protective role in the ectopic ossification process because the same pattern was observed in undifferentiated Ob cells and nonossified posterior longitudinal ligament cells.

effects of Strain Distribution in the Intervertebral Discs on the Progression of Ossification of the Posterior Longitudinal Ligaments

Study Design Strain distribution in the intervertebral discs was evaluated biomechanically using an engineering true strain calculation formula. Objectives This study was performed to clarify the involvement of dynamic factors in the progression of ossification of the posterior longitudinal ligament. Summary of Background Data In patients with ossification of the posterior longitudinal ligament of the cervical spine, ossification frequently progresses after laminectomy. This suggests the involvement of dynamic factors in the progression of ossification. However, these factors have not yet been clarified. Methods The analysis was performed on 101 patients with ossification of the posterior longitudinal ligament by employing dynamic lateral x-ray films of the cervical spine. The x-ray films were digitized and used as computer data for calculating the strain distribution. x-ray films were obtained again 5 years later, and the strain distribution and the presence or absence of progression of ossification were evaluated. Results The progression of ossification of the posterior longitudinal ligament was highly correlated with abnormal strain distribution in the intervertebral discs. Progression of ossification was frequently observed in areas having disc distortion in tension and extension on the posterior longitudinal ligament. Conclusions In this study, the area of progression of ossification corresponded to the area showing uneven strain distribution and resultant concentration of dynamic stress. These results suggest an important role for dynamic factors in the progression of ossification of the posterior longitudinal ligament.

Restriction fragment length polymorphism of genes of the α2(XI) collagen, bone morphogenetic protein-2, alkaline phosphatase, and tumor necrosis factor-α among patients with ossification of posterior longitudinal ligament and controls from the Japanese population

Study Design The present study analyzed the restriction fragment length polymorphism patterns of α2(XI) collagen, bone morphogenetic protein‐2, alkaline phosphatase, and tumor necrosis factor‐α genes in patients with ossification of the posterior longitudinal ligament. This study investigates the genetic polymorphism of bone‐induced factors in patients with ossification of the posterior longitudinal ligament and compares it with healthy control subjects. Objectives To clarify the genetic markers linked to ossification of the posterior longitudinal ligament. Summary of Background Data Ossification of the posterior longitudinal ligament is a genetic disease associated with abnormal calcium metabolism involving the posterior longitudinal ligament. Previous genetic studies have not identified the pathologic mechanism of ossification of the posterior longitudinal ligament. Histopathologic studies of ossification of the posterior longitudinal ligament and the animal model, the spinal hyperostotic mouse, have revealed an increase in Type XI collagen and bone morphogenetic protein‐2 expression. Methods Eighteen Japanese patients with ossification of the posterior longitudinal ligament and 51 healthy, unrelated control subjects were investigated for the restriction fragment length polymorphism patterns of COL11A2, bone morphogenetic protein‐2, alkaline phosphatase, and tumor necrosis factor‐α, genes with various restriction endonucleases. Results The gene frequencies of COL11A2 obtained with BamHI (10.0 kb fragment) and HindIII (19.0 kb fragment) observed in patients with ossification of the posterior longitudinal ligament were higher compared with control subjects (0.43 and 0.14, respectively). These differences were statistically significant (BamHI P = 0.018; HindIII P = 0.046). Two new restriction fragment length polymorphism patterns were detected of the bone morphogenetic protein‐2 gene with Mspl and Taql and one already known restriction fragment length polymorphism pattern of the tumor necrosis factor‐α gene with Ncol. However, they were not significantly different from the control subjects. Conclusion Seven restriction fragment length polymorphisms of COL11A2 gene were identified. Two of them (BamHI, 10.0/10.0 kb genotype; HindIII, 19.0/19.0 kb genotype) were significantly different in patients with ossification of the posterior longitudinal ligament.

Comparison of operative results of lumbar disc herniation in manual laborers and athletes.

The results of various surgical treatments for lumbar disc herniation in laborers and athletes were compared on the basis of the relative success of return to work and athletic activity. The rate of successful return to manual labor was the highest at 89% after spinal fusion, but no difference was observed between simple disc excision and percutaneous discectomy. Return to competitive sports was achieved at rate of 81% after percutaneous discectomy, and the time until return to sports activity was significantly shorter than after other procedures. In individuals whose lumbar region is expected to be subjected to great mechanical stress, it is important to take work needs and the special needs of athletes into consideration when selecting the surgical procedure.

Bone mineral density in patients with ossification of the posterior longitudinal ligament in the cervical spine.

Abstract: Bone mineral density (BMD) has not been clearly determined in patients with ossification of the posterior longitudinal ligament (OPLL) in the cervical spine. BMD in patients with OPLL was measured in the third vertebral body in the lateral projection and in the distal part of the radius in the anteroposterior projection using dual-energy X-ray absorptiometry (DXA). Patients with OPLL had significantly higher BMD than healthy controls in both the lumbar spine and radius. Observing BMD by gender and age group, high BMD was recognized especially in female patients over 60 years of age. Significantly increased BMD was observed in patients with ankylosing spinal hyperostosis (ASH) in addition to OPLL. These findings suggest that patients with OPLL may tend to develop systemic hyperostosis, leading to the pathological ectopic ossification observed in OPLL.