REPAIR OF DEFECTS IN SPONDYLOLYSIS BY SEGMENTAL PEDICULAR SCREW HOOK FIXATION - A PRELIMINARY-REPORT

Study Design. Clinical testing of segmental pedicular screw hook fixat ion repairing defects in lumbar spondylolysis. Objectives. 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 br eak while fusion takes place without a postoperative body cast. Summar y of Background Data. 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. M ethods. This technique stabilizes bone grafted to the defect by a pedi cular screw, a hook, and a rod used in combination. Six patients with lumbar spondylolysis were treated by means of this technique. Results. Postoperatively, all patients with low back pain or radicular pain ex perienced significant relief. Radiographs, including lateral flexion-e xtension radiographs and tomograms, showed five patients to have a bil ateral union and one a unilateral union, and none of the instrumentati on failed. Conclusion. This technique is considered useful for direct repair of the defects found in lumbar spondylolysis.