Koichi Saotome

The relationship between facet joint osteoarthritis and disc degeneration of the lumbar spine: an MRI study

The role of MRI in assessing facet joint osteoarthritis is unclear. By developing a grading system for severity of facet joint osteoarthritis on MRI, the relationship between disc degeneration and facet joint osteoarthritis was determined. The accuracy of MRI in assessing facet joint osteoarthritis against CT was 94%. Under 40 years of age, the degree of disc degeneration varied among individuals. Over the age of 60, most of the discs were markedly degenerated. Under 40 years of age osteoarthritic changes in facet joints were minimal. Over the age of 60, variable degrees of facet joint osteoarthritis were observed but some facets did not show osteoarthritis. No facet joint osteoarthritis was found in the absence of disc degeneration and most facet joint osteoarthritis appeared at the intervertebral levels with advanced disc degeneration. Disc degeneration is more closely associated with aging than with facet joint osteoarthritis. The present study supports the hypothesis that “disc degeneration precedes facet joint osteoarthritis”, and also supports the concept that it may take 20 or more years to develop facet joint osteoarthritis following the onset of disc degeneration.

The relationship between disc degeneration, facet joint osteoarthritis, and stability of the degenerative lumbar spine

Degenerative processes in the disc and facet joints affect the stability of the motion segment. The exact relations among disc degeneration, facet joint osteoarthritis, and the kinematics of the motion segment are not well defined in the literature. Magnetic resonance imaging and functional radiography of the lumbar spine were analyzed to examine the relations among segmental instability, facet joint osteoarthritis, and disc degeneration in patients with degenerative disorders of the lumbar spine. Seventy consecutive patients (mean age, 46 years) had both magnetic resonance imaging and flexion and extension radiographs of the lumbar spine. The lumbar instability was classified into abnormal tilting on flexion, rotatory instability in the sagittal plane, and translatory instability. Translatory instability was subdivided into anterior, posterior, and anteroposterior translatory instability. Disc degeneration as seen on T2-weighted sagittal images was classified into five grades. Facet joint osteoarthritis as seen on axial T1-weighted images was divided into four grades. This study revealed that the kinematics of the lumbar motion segment are affected by disc degeneration and facet joint osteoarthritis. Abnormal tilting movement on flexion and anteroposterior translatory instability both had negative associations with facet joint osteoarthritis. However, anterior translatory instability was positively associated with disc degeneration and facet joint osteoarthritis. Rotatory instability in the sagittal plane and posterior translatory instability were not associated with disc degeneration and facet joint osteoarthritis.

Association of the Japanese Orthopaedic Association Score With the Oswestry Disability Index, Roland-Morris Disability Questionnaire, and Short-Form 36

Study Design. Cross-cultural translation and cross-sectional psychometric testing were performed. Objectives. To cross-culturally translate the Oswestry Disability Index (ODI) and the Roland-Morris Disability Questionnaire (RMDQ) into Japanese, and to compare the Japanese Orthopaedic Association (JOA) score with the ODI and the RMDQ score. Summary of Background Data. The two most widely used back-specific measures, the ODI and the RMDQ, have not been translated into Japanese. The JOA score has been used extensively in Japan. However, this score has not been tested in terms of its reliability and validity. Methods. The ODI and RMDQ were translated into Japanese using the process of forward translation, synthesis of translation, backward translation, expert committee, test of the prefinal version, and submission of the documentation to the developers. The JOA score, ODI, and RMDQ were tested with 97 patients who had degenerative lumbar spinal disorders (average age, 51 years). The correlation among the three disease-specific measures (JOA score, ODI, and RMDQ) and eight subscales of a generic health measure, the Medical Outcomes Survey Short-Form 36 (SF-36), was calculated. The reproducibility of the JOA score also was investigated. Results. Reliability, as estimated by internal consistency, reached a Cronbach alpha of 0.83 for the ODI and 0.86 for the RMDQ. The calculated test–retest reliability was 0.93 (P < 0.01; n = 20) for the ODI and 0.95 (P < 0.01; n = 20) for the RMDQ. The correlation of the JOA score with the ODI was −0.647 (P < 0.01), and with RMDQ was −0.568 (P < 0.01). There also was a significant correlation between the ODI and the RMDQ (r = 0.785; P < 0.01). There was a significant correlation between the three disease-specific measures (JOA score, ODI, and RMDQ) and all the subscales of the SF-36 (P < 0.01). The calculated reproducibility of the JOA score was as follows: interobserver error (r = 0.92, P < 0.01), test–retest reliability (r = 0.91, P < 0.01). Conclusions. The Japanese versions of the ODI and the RMDQ were reliable and valid. The use of these translated instruments can be recommended for future clinical trials in Japan. The results also showed the JOA score had acceptable psychometric properties of reliability and construct validity, suggesting that this score is reliable and valid. Further studies are needed to verify the validityand responsiveness of the JOA score.

Orientation and osteoarthritis of the lumbar facet joint.

Several studies have shown an association between sagittal orientation of the facet joint and degenerative spondylolisthesis. There is currently no information available on the association between orientation of the facet joint and osteoarthritis. This study examined the association between orientation and osteoarthritis of the lumbar facet joints. One hundred eleven consecutive patients underwent plain radiography and magnetic resonance imaging. These patients were divided into two groups: No Degenerative Spondylolisthesis Group (98 patients) and Degenerative Spondylolisthesis Group (13 patients). In the No Degenerative Spondylolisthesis Group, segments with higher grades of osteoarthritis showed more sagittal orientation of the facet joints at the L3–L4 and L4–L5 levels. The facet joint was oriented significantly more sagittally in the Degenerative Spondylolisthesis Group than in the No Degenerative Spondylolisthesis Group at the L4–L5 and L5–S1 levels. The severity of facet joint osteoarthritis was significantly higher in the Degenerative Spondylolisthesis Group than in the No Degenerative Spondylolisthesis Group at the L3–L4, L4–L5, and L5–S1 levels. A significant association was found between sagittal orientation and osteoarthritis of the lumbar facet joints, even in patients without degenerative spondylolisthesis. Facet joint osteoarthritis, rather than spondylolisthesis, is the pathoanatomic feature that is associated with sagittal orientation of the facet joints in patients with degenerative spondylolisthesis.

First histologically confirmed case of a classic chordoma arising in a precursor benign notochordal lesion: differential diagnosis of benign and malignant notochordal lesions

Abstract. The first histologically confirmed case of a classic chordoma arising in a precursor benign notochordal lesion is presented and the differential diagnosis between benign and malignant notochordal lesions is discussed. A 57-year-old man presented with a classic chordoma in the coccyx. The resected specimen demonstrated a small intraosseous benign notochordal lesion in the coccyx, which was adjacent to the classic chordoma. Also seen were two separate, similar benign lesions in the sacrum. The classic chordoma consisted of multiple lobules that were separated by thin fibrous septa and that showed cords or strands of atypical physaliphorous cells set within an abundant myxoid matrix. In contrast, the benign lesions consisted of intraosseous sheets of bland physaliphorous cells without any extracellular matrix. The affected bone trabeculae showed sclerotic reactions. It was concluded that benign and malignant notochordal lesions can be distinguished microscopically.

Morphologic changes in the cervical neural foramen due to flexion and extension: in vivo imaging study.

Study Design. Dimensional measurement of cervical neural foramen at various positions, using reformatted computed tomography. Objectives. To examine the morphologic changes in the neural foramen during flexion and extension of the cervical spine in vivo. Summary of Background Data. Previous cadaveric studies have shown the effect of cervical spinal motion on dimensions of the neural foramen. However, little information is available about dynamic morphologic changes in the cervical neural foramen in vivo. Methods. Cervical CT images of seven healthy volunteers were taken at the neutral position, maximum extension, and maximum flexion, and were reconstructed in the oblique plane perpendicular to the long axis of each neural foramen from the C3–C4 to C6–C7 level. Measured parameters included foraminal height, width, cross-sectional area, and segmental sagittal rotation at each spinal level. Differences in neural foraminal dimensions among these positions were analyzed. Correlations of segmental sagittal rotation with differences in dimensions between flexion and extension were analyzed. Results. Flexion significantly increased the foraminal height (by 1.0 mm; 11%), foraminal width (by 1.0 mm; 16%), and foraminal area (by 12 mm2; 28%) (P < 0.01). Extension significantly decreased the foraminal height (by 0.9 mm; 10%), foraminal width (by 1.4 mm; 22%), and foraminal area (by 8.0 mm2; 17%) (P < 0.01). Segmental sagittal rotation significantly positively correlated with % change in foraminal height (r = 0.434, P < 0.01) and area (r = 0.504, P < 0.01). Conclusions. The present results are consistent with those of previous in vitro studies and may explain the clinical observation that cervical extension aggravates symptoms in patients with cervical radiculopathy and that flexion often relieves them.

Para-articular chondroma and osteochondroma of the infrapatellar fat pad : a report of three cases

Abstract We report three cases of para-articular chondroma and osteochondroma in the region of infrapatellar fat pad. All three lesions were resected and examined histologically. Two of them were primarily cartilaginous with a lobular pattern internally, and one uniformly osseous with peripheral cartilage. We conclude that these lesions are not the same. The former should be designated para-articular chondroma after Jaffe and the latter, osteochondroma.Résumé Nous rapportons trois cas de chondrome para-articulaire et d’ostéochondrome situés dans le corps adipeux infrapatellaire. Ces trois lésions ont été résequèes et examinées histologiquement. Deux d’entre elles étaient au départ cartilagineuses et avaient une forme lobulaire interne, et l’autre était uniformement osseuse avec un cartilage périphérique. Nous en concluons que ces lésions ne sont pas les mêmes histopathologiquement. Les premières devraient être appelées, à la suite de Jaffe, chondrome para-articulaire et la troisième, ostéochondrome, de façon à l’opposer aux dénominations équivoques utilisées dans les présentations précédentes.

The Interspinous Ligament of the Lumbar Spine : Magnetic Resonance Images and Their Clinical Significance

Study Design. A preliminary study of magnetic resonance features of the interspinous ligament in degenerative lumbar spine. Objectives. To classify the magnetic resonance imaging features of the interspinous ligaments in relation to the patient’s age, disc degeneration, and radiographic instability. Magnetic resonance imaging also was correlated with the histologic findings of the interspinous ligaments. Summary of Background Data. As reported, rupture of the interspinous ligament frequently is found in the degenerative lumbar spine. However, little information is available in the literature on imaging assessment of the interspinous ligament in degenerative lumbar disorders. Methods. In this study, 24 interspinous ligaments at L1–L2 or L2–L3 from 15 patients with nondegenerated discs were selected to represent normal magnetic resonance features of the interspinous ligament, and 38 patients with the mean age of 49 years underwent functional radiography and magnetic resonance imaging. The magnetic resonance features of the interspinous ligament were classified into five categories according to their signal intensities: Type 1A (low intensity on T1- and T2-weighted images without hypertrophy of the spinal process); Type 1B (same signal pattern as in Type 1A withhypertrophy of spinal process); Type 2 (low intensity on T1- and high intensity on T2-weighted images); Type 3 (high intensity on T1-weighted images); and Type 4 (others). Seven patients with variable patterns of the interspinous ligament were selected to undergo histologic examinations. Results. Of the interspinous ligaments considered normal, 80% were classified as Type 1A. There were 14 Type 1A, 30 Type 1B, 19 Type 2, 16 Type 3, and 20 Type 4 ligaments. The mean age and disc degeneration grade of the patients with the Type 1B ligaments was significantly higher. Instability was found to be associated with Type 2 interspinous ligaments (7 of 19), whereas instability rarely was noted in Types 1A (1 of 14) and 1B (1 of 30) ligaments. The histologic examination revealed that chondrometaplasia and necrotization of fiber bundle predominated in Type 1B, proliferation of cells and vascular invasion in Type 2, fatty degeneration in Type 3 ligaments. Conclusions. The magnetic resonance imaging characteristics may be helpful in assessing normal or pathologic changes in the interspinous ligaments.

Anatomy of the iliolumbar ligament

Information is lacking in the literature on the precise anatomy of the iliolumbar ligament and its individual differences. The morphologic pattern, length, and width of the iliolumbar ligament were determined in 56 embalmed lumbosacral spines from human cadavers. It was possible to classify the iliolumbar ligament into two groups: Type A (74 ligaments), in which anterior and posterior ligaments had separate courses; and Type B (32 ligaments), in which anterior and posterior ligaments moved together as one band. The angle of the posterior iliolumbar ligament in Type A was oriented significantly more posteriorly than that in Type B. The posterior iliolumbar ligament was significantly shorter and oriented more posteriorly in male anatomic specimens than in female ones.

Type I and type III procollagen gene expressions in the early phase of ligament healing in rabbits: an in situ hybridization study.

The purpose of this study is to observe type I and type III procollagen gene expressions in the healing ligament using in situ hybridization histochemistry. The rabbit medial collateral ligaments were incised and harvested at 3, 7, 14, and 28 days postoperatively. The healing ligament showed increased expression of both procollagen genes through this period compared with the unoperated ligament. The peak expression level was observed at 7 or 14 days for type I and at 7 days for type III, respectively. The strongest expression of both genes was detected in the scar tissue created between the ends of the old ligament. Although type III procollagen gene expression was observed almost only in the newly created scar tissue, type I procollagen gene was expressed not only in the scar tissue, but also at the ends of the previously normal ligament. These results suggest that type I collagen synthesis begins shortly after ligament injury and occurs at the ends of the injured ligament as well as in the scar tissue, and that type III collagen is largely synthesized in the scar tissue around one week after injury but continues being synthesized for at least four weeks after injury.