The Graf ligamentoplasty procedure - Comparison with posterolateral fusion in the management of low back pain

Study Design. A retrospective case-control comparison between the Soft Tissue Stabilization System according to Graf and instrumented posterolateral fusion in a consecutive series of patients operated on by a single surgeon. Objectives. To compare clinical and radiologic outcomes at 1 and 2 years. Summary of Background Data. Although series have been reported showing encouraging results with the use of the Graf ligamentoplasty for low back pain no comparative data are available on outcome when compared with those in more conventional treatments. Methods. Eighty-three consecutive patients operated on for low back pain in a single surgeon's practice (TMH) were recalled for clinical and radiologic review. Patients underwent either soft tissue stabilization or posterolateral fusion with pedicle screw instrumentation. Each patient chose between the procedures after advice that the Soft Tissue Stabilization System, although experimental, was a reversible procedure. Independent observers conducted the review at 1 and 2 years. The Low Back Outcome Score was used as an objective measure of outcome. In addition to this, patients underwent computed tomographic assessment of pedicle screw placement. Results. There was no statistically significant difference between groups in age, sex, body weight, symptom duration, previous surgery, dependency on workers' compensation, preoperative diagnosis, smoking habits, and the number of motion segments instrumented. There was a significantly better outcome, when measured by the Low Back Outcome Score in the group of patients managed by posterolateral fusion at 1 year (P = 0.02), although at 2 years the difference was less (P < 0.34). Patients with facet joint-related pain did no better after Soft Tissue Stabilization than did patients of other diagnostic groups. Compensable cases did better at 1 year after fusion (P < 0.003), although again the difference was less marked at 2 years (P = 0.09). There was a trend toward a higher revision rate in the Soft Tissue Stabilization System group (P = 0.11) at 1 year with a statistically significant (P = 0.01) difference apparent at 2 years. Revision after Soft Tissue Stabilization was associated with a poorer outcome, similar to that seen in revision after fusion. Pedicle screw misplacement rates were no different between the two groups and increased in frequency at the more cranial vertebral levels. Conclusions. Outcome after Soft Tissue Stabilization was associated with a worse outcome at 1 year and a significantly higher revision rate at 2 years. Revision was associated with a poor outcome similar to that seen in revision after fusion.