Cervical laminoplasty to enlarge the spinal canal in multilevel ossification of the posterior longitudinal ligament with myelopathy.

We studied 23 patients with severe myeloradiculopathy involving multiple (more than three) levels of ossification of the posterior longitudinal ligament (OPLL) of the cervical spine, who were treated with laminoplasty to enlarge the spinal canal. The resected spinous processes were used as bone grafts to support the opened laminae. These patients were analyzed pre- and postoperatively with a neurological evaluation according to the Japanese Orthopedic Association (JOA) score system for cervical myelopathy. Follow-up was from 2.0 to 5.3 years with an average of 31.5 months. The results were compared with those in 31 patients with the same degree (multilevel) of OPLL who had been operated upon previously by laminectomy (14 cases) or anterior resection (17 cases). Postoperative neurological recovery by improvement ratio of the JOA score was observed in 81.2% of those who had undergone expansive laminoplasty, in 72.4% of those with laminectomy, and in 63.6% of those with anterior decompression. We concluded that expansive laminoplasty is a safer procedure with fewer complications. Stability is achieved by fixing the expanded laminae permanently with a bone graft. The neurological recovery following our technique of laminoplasty and fusion appears to be superior to that with laminectomy or anterior decompression.