Treatment of Degenerative Lumbar Instability with Semi-Rigid Isolock System

ABSTRACT

For degenerative lumbar instability, various spinal instrumentations have been used to relieve clinical symptom and to stabilize the spine. Most of them are rigid fixation which cause a postfusion instability at adjacent segment with high incidence. It creates a highly susceptible region(neo-hinge) between fixed rigid segment and nonfixed mobile segment. Eventually acceleration of degenerative change in adjacent segment is resulted with clinical deterioration. To avoid of postfusion instability after rigid fixation, a semi-rigid fixation system which has a intermediate transitional zone is developed. In 98 patients with degenerative lumbar instability, semi-rigid fixation which had a damper in the middle of plate were performed with CH titanium cage. Angular instability in lateral dynamic X-ray was improved in all case immediately after operation. Translational instability also much improved. But no degenerative change or instability in adjacent segment(neo-hinge disc) or overlying disc within fusion segment during follow up period of average 16 months. Excellent and good clinical results were achieved in 90.8% of patients and the solid bone fusion was occurred in 98.9%.