Evaluation was done of 65 patients with cervical myelopathy treated by bilateral open laminoplasty using artificial laminas, between 1984 and 1988, who had been followed for more than 2 years. The mean recovery rate on the Japanese Orthopaedic Association scoring system was 65% in all cases, and 72% in the cases with no other complications. The artificial laminas appeared well adapted to the laminas in computed tomography and dynamic radiographic examinations, and there were no cases of reduction of the enlarged canal. Postoperative restriction of the range of motion of the cervical spine was lessened by the positioning of lateral grooves, more appropriate external fixation, and posterior flexion exercise after operation. This procedure is not technically complicated, it does not involve appreciable blood loss during operation, it prevents grafted free fat from migrating into the spinal canal, and is advantageous for poster-olateral bone chip grafting.