TECHNICAL IMPROVEMENTS AND RESULTS OF OPEN-DOOR EXPANSIVE LAMINOPLASTY WITH HYDROXYAPATITE IMPLANTS FOR CERVICAL MYELOPATHY

OBJECTIVE: A new, modified technique of cervical open-door laminoplasty with hydroxyapatite implants was developed to enlarge the spinal canal in stable fashion yet preserve the architecture of the cervical spine and surrounding tissues. To assess the efficacy of this technique, a retrospective review of neurological and radiological outcomes after cervical laminoplasty was conducted. METHODS: Clinical charts and cervical x-rays of 151 patients with cervical stenotic myelopathy were reviewed. Patients were treated with the cervical laminoplasty between May 2001 and January 2002. The patient group comprised 69 women and 82 men ranging in age from 30 to 86 years (mean, 63 yr). Neurological outcomes were evaluated according to the Japanese Orthopaedic Association grade. To assess alignment and mobility of the cervical spine, the C2-C7 angle was used. RESULTS: The average Japanese Orthopaedic Association grade was 8.1 +/- 2.5 before surgery and 15.2 +/- 1.5 at 1 year after surgery (P < 0.01). No neurological complications were observed. The average C2-C7 angle at the neutral position increased from 8.3 +/- 11.7 degrees before surgery to 14.9 +/- 11.6 degrees at 1 year after surgery (P < 0.01). The range of motion between C2 and C7 was 36.9 +/- 12.5 degrees and 29.1 +/- 10.8 degrees before and 1 year after surgery, respectively. CONCLUSION: A new modified technique of cervical open-door laminoplasty described herein offers some solutions to the problems associated with conventional techniques of cervical laminoplasty.