Graf Soft Fixation for the Treatment of Degenerative Lumbar Disease

ABSTRACT

Degenerative involution of the spine causes destruction of spinal stabilizer which consists of bone, ligament, joint capsule, and disc, which substantially leads to hypermobility and instability of the spine. Generally the hard fixation system has been used for the treatment of lumbar instability. However, it has many complications, including screw loosening, screw fracture, and instability on, above, and below the fusion segment. These complications of the hard fixation system has brought to the invention of a more physiologic fixation device, the soft fixation system. We have used the Graf soft fixation system as an instrument for degenerative lumbar disease. 106 cases were operated between August, 1993 and March, 1996. The clinical assessments, radiologic findings, and operative results were analyzed. The height of disc space significantly increased from 8.84mm to 9.84mm on L3/4, 9.28mm to 10.13mm on L4/5, and 9.44mm to 10.47mm on L5/S1. Flexion instability changed from -6.9 degrees to 5.5degrees on L3/4, -7.45 degrees to 5.04 degrees on L4/5, -2.09degrees to 10.81degrees on L5/S1, translation instability was corrected from 16.8% to 14.9% on L3/4, 19.9% to 12.4% on L4/5, 27.1% to 20.1% on L5/S1 after Graf soft fixation. The clinical results were as follows excellent in 56%, 27% good, 9% fair, and 8% poor. These results suggest that Graf soft fixation system for degenerative lumbar disease would not only be useful and effective, but also be safer in terms of unwanted complications of the hard fixation system.