OBJECTIVETo study the imageology changes of degenerative cartilage endplate to different degree, and to explore its clinical significances.

METHODSThe imageology data (MRI or CT) of 58 patients with degenerative disc disease of L4, 5 (including 34 patients with lumbar disc herniation). The patients were divided into three groups depending on the mean signal intensity rate of degenerative disc and cerebrospinal fluid: light degenerative group of 17 cases, intermediate degenerative group of 17 cases, and severe degenerative group of 24 cases. The signals of intervertebral disks on T2WI of sagittal magnetic resonance imaging were inputted into the computer and the concave angles of endplate were measured. Anteroposterior diameter and transverse diameter of the endplate were measured from the CT scan of L4, 5, and then the relative curvature of endplate was got. The change patterns of the concave angle and the relative curvature of vertebral endplates were analyzed when the lumbar disc was differently degenerative.

RESULTS(1) The concave angle of endplate (L4 inferior endplate, L5 superior endplate) gradually increased among the light degenerative group, intermediate degenerative group and severe degenerative group (P < 0.01). (2) The relative curature of endplate (L4 inferior endplate, L5 superior endplate) gradually increased. There was significant difference between the light degenerative group and intermediate degenerative group (P < 0.0l), and there was significant difference between the light degenerative group and severe degenerative group (P < 0.0l). There were no significant difference between intermediate degenerative group and severe degenerative group (P < 0.05). (3) The concave angle of endplate had positive correlation with relative circularity (r = 0.786, 0.490).

CONCLUSIONThe concave angle and relative curvature of endplate generate corresponding changes when the lumbar disc are differently degenerative. The changes of concave angle and relative curvature of endplate are important factors of lumbar disc hernia and lower back pain, which may evaluate the probability of intervertebral disk hernia.