Modeling the annular incision in a herniated lumbar intervertebral disk to study its effect on disk stability

Several techniques of lumbar disk annulotomy have been described in clinical reports, but have not addressed the influence of annulotomy type on motion-segment stability. The technique used to incise during diskectomy may play a role in the subsequent healing and biomechanical stability of the disk. The purpose of this study is to develop a finite-element model using ADINA to study the influence of annulotomy-technique selection on disk competence. The analyses showed that both the box- and slit-type annular incisions produced similar changes in the biomechanical characteristics of the disk excepting the stresses in the disk annulus. The study also showed that there is no preference between the two annular incisions as far as post-surgical stability of the disk is concerned. (C) 1997 Elsevier Science Ltd.