[Histopathological study on the intervertebral discs of idiopathic scoliosis (author's transl)].

To elucidate morphologic events, 74 intervertebral discs removed by Dwyer instrumentation from 15 scoliotic patients and 10 intervertebral discs by anterior spinal wedge osteotomy from 10 patients were examined, along with 33 intervertebral discs from autopsy cases. Paraffin sections were stained with PAS, toluidine blue and alcian blue in addition to routine stainings. The results obtained are as follows: (1) Noticeable differences in stainability of cartilaginous plate, cleft and vacuolation of the matrix of annulus fibrosus and cellular decrease were obtained in nucleus pulposus in scoliotic patients as compared with controls. Chordal cells in nucleus pulposus were found in 30% of scoliotic patients and 9% of controls. (2) In the apical discs, ossification gap of cartilaginous plate decreased, while cleft and vacuolation of annulus fibrosus and formation of cartilage cell cluster in nucleus pulposus were increased. (3) Irregular fiber running, cleft and vacuolation of annulus fibrosus were found in scoliotic patients with the curvature of the spine by more than 60 degrees. Matrix degeneration of cartilaginous plate and irregular fiber running of annulus fibrosus were common in scoliotic patients with higher rotation than grade III of Nash & Moe classification. Conversely, chordal cells in nucleus pluposus were not common in higher rotation cases. Chordal cell remnants were prominent in nucleus pulposus in scoliotic patients. This suggests that some abnormalities occurring during the maturation process of nucleus pulposus are related to the evolution of scoliosis.