Purpose: Cervical laminoplasty has been used for the treatment of cervical arthrosic myelopathy in Japan. The purpose of this work was to assess clinical and radiological outcome at more than two years follow-up.

Material: Thirty-one patients underwent laminoplasty of three levels or more for cervical arthrosic myelopathy and were reviewed more than two years after surgery.

Methods: The Japanese Orthopaedic Association score was used to assess function preoperatively and at last follow-up. Preoperative and last follow-up standard strict lateral and flexion and extension x-rays of the cervical spine were available for all patients. The curvature was assessed on the lateral view in the neutral position (C2–C7 Cobb angle). Overall mobility was assessed on the dynamic views.

Results: The mean preoperative score was 9.7, improving to 138 at last follow-up (p < 0.0001, paired t test). Mean relative gain was 52.9%. The mean Cobb angle was 17° preoperatively and 8.9° at last follow-up. Cervical spine curvature and overall mobility had no influence on the score at last follow-up. The postoperative Cobb score was only influenced by the preoperative angle (p < 0.0001). There were no reoperations for instability.

Discussion: Guigui has demonstrated that mean loss of cervical lordosis in a series of extended laminectomies was 14°. In our series, mean loss of cervical lordosis was 8.1°. Laminoplasty enables a better preservation of cervical lordosis than laminectomy. Guigui also reported three patients requiring reoperation because of an unstable spine after laminectomy. Inversely, we did not have any cases requiring reoperation. During laminoplasty, a gutter is fashioned in a medial quarter of the articular masses to open the lamina, producing their fusion. This unexpected fusion diminishes overall mobility but also has a less destabilising effect on the spine than laminectomy.