Repair of defects in spondylolysis by segmental pedicular screw hook fixation. A preliminary report.

Abstract

Clinical testing of segmental pedicular screw hook fixation repairing defects in lumbar spondylolysis. The authors tested segmental pedicular screw hook fixation using ISOLA implants (AcroMed Corp., Cleveland, OH) to maintain direct repair of the defect in pars interarticularis while fusion occurs. The device should not break while fusion takes place with out a postoperative body cast. Previous techniques of direct repair of defects in lumbar spondylolysis have not been successful universally, and wire breakage has occurred despite the use of a postoperative body cast. This technique stabilizes bone grafted to the detect by a pedicular screw, a hook, and a rod used in combination. Six patients with lumbar spondylolysis were treated by means of this technique. Postoperatively, all patients with low back pain or radicular pain experienced significant relief. Radiographs, including lateral flexion-extension radiographs and tomograms, showed five patients to have a bilateral union and one a unilateral union, and none of the instrumentation failed. This technique is considered useful for direct repair of the defects found in lumbar spondylolysis.