Graf Soft Fixation for the Treatment of Degenerative Lumbar Disease

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.

Surgical treatment of Degenerative Lumbar Spinal Disorders Using the Graf System: over three year results / 대한정형외과학회잡지

The Graf system has supposed advantages with its flexible nature, as compared with rigid fixation. But there have been no reports about effects in the adjacent motion segment after soft stabilization. The purpose of this study was to evaluate the radiologic changes occuring in the adjacent segments of the Graf system and to assess its ability stabilizing the lumbar spine. A retrospective review of radiographs and medical records was undertaken in 32 cases who had been treated with the Graf system in degenerative lumbar spinal disorders. The average age at operation was 52.5 years and the average follow up period was 49.6 months. The results of this study were as follows: clinical assesments based on the Kirkaldy-Willis criteria revealed excellent in 13 cases (40.6%), good in 16 cases (50%), fair in 2 cases (6.3%) and poor in 1 case (3.1%). Radiologically we analysed the adjacent segments in 25 cases except the cases which did not have the correspondence between the clinical findings and the radiological findings, and the fixated segments in 32 cases. The acceleration of degenerative changes were found in the above adjacent segments in 11 cases (44%) and in the below adjacent segments in 5 cases (27.7%). Also, those changes were found in the fixated segments with discectomy in 19 cases (50%) and in the fixated segments without discectomy in 9 cases (37.5%). In conclusion, we think that the Graf system in a lumbar region may biomechanically influence the adjacent segments. The mechanical effects of the device could be changed by the polyester bands which were followed for a longer period of time in the fixated segments. Therefore, randomized prospective studies comparing the Graf system to other treatement methods could provide clear indications for lumbar spinal disorders.