Laminoplasty by splitting the spinous process is an established treatment procedure for patients with cervical spondylotic myelopathy (CSM) or ossification of the posterior longitudinal ligament (OPLL). We have used a hydroxyapatite spacer as an intraspinous spacer since February, 1991 and evaluated its bonding to the split lamina by computed tomography. Sixty patients (47 men, 13 women) underwent laminoplasty by splitting the spinous process. Their mean age at the time of surgery was 60 years, and the follow-up period ranged from 4 to 28 months (mean 15 months). The spacer has a hole and was fixed to the spinous process using two silk threads. Approximately 10% of spacers showed ossification and 20% showed sclerotic changes between the spacer and lamina. Only three cases showed obvious displacement of the spacer but they had no problems clinically. All other cases had a stable fixation.