We investigated the clinical results of 39 patients with ossification of the posterior longitudinal ligament (OPLL) of the cervical spine who underwent expansive laminoplasty by sagittal splitting of the spinous process (Kurokawa’s method), from January 1995 to October 2000. The mean age was 62 (42 to 75) years. The operative results were evaluated according to the Japanese Orthopaedic Association (JOA) score, after a mean follow-up period of 38 (12 to 77) months. The mean JOA score was 7.82 points before surgery and 12.73 points after surgery. The overall mean recovery rate by JOA score was 52.5%. The patients were divided into two groups; Group 1 consisting of 8 patients with spinal canal stenosis due to OPLL or ossification of the ligamentum flavum etc. at the thoracic and/or lumbar level, and Group 2 consisting of 31 patients without stenosis. The mean JOA score of Group 1 was 6.75 points before surgery and 10.94 points after surgery, while the score of Group 2 was 8.10 points before surgery and 13.20 points after surgery, with no significant difference in the score before surgery between the two groups. However, the JOA score after surgery was significantly lower in patients with spinal canal stenosis at the thoracic and/or lumbar level of Group 1, than the patients without stenosis in Group 2.
