[Osteoplastic laminectomy using hydroxyapatite ceramic implants].

Cervical osteoplastic laminectomy using ceramic or apatite beads as implants was performed in 31 patients with symptomatic cervical bony canal stenosis. Patients with degenerative changes such as osteochondrosis or disc herniation are included in this study but those with spinal cord tumor, arachnoid cyst or ossification of the posterior longitudinal ligament are not. Initially foraminotomies were performed at the C5-8 levels in an attempt at preventing worsening of radicular signs caused by posterior displacement of the cord and resultant tethering effect on the nerve root. Connecting the medial borders of the foraminotomies, laminae were removed in a single piece. A small suboccipital craniectomy and C1-2 laminectomy were added when necessary. Laminae were replaced maintaining an increased anteroposterior diameter of the bony canal, by means of interposition of apatite or ceramic beads of appropriate size between the cut surfaces of the laminae. Results were excellent in 13 (42%), good in 10 (32%), fair in 4 (13%), no change in 2 (6.5%) and worse in 2 (6.5%). Literature on the osteoplastic laminectomy (laminoplasty) for cervical canal stenosis was reviewed and the advantage of the present method was briefly discussed.