We evaluated the lumbar discs of 31 patients with degenerative spondylolisthesis using magnetic resonance imaging. The shape of degenerative spondylolisthesis was classified into anterior open, posterior open and parallel type by plain lateral radiograph. The grade of disc degeneration, defined as reduced disc signal intensity, was significantly higher in the parallel and posterior open type than in the anterior open type. Disc degeneration at the adjacent level and slip rate were also higher in proportion to the grade of disc degeneration at the involved level. Range of motion of the lumbar spine tended to decrease at the involved level and increase at the adjacent level as the grade of spondylolisthetic disc degeneration worsened.
