A Minimum 10-Year Follow-up of Posterior Dynamic Stabilization Using Graf Artificial Ligament

Abstract

A retrospective long-term follow-up study. To report minimum 10-year follow-up results of posterior dynamic stabilization using Graf artificial ligament and to evaluate the role and limitations of this procedure in the treatment of degenerative lumbar disorders. Motion-preserving surgeries, including artificial disc replacement and ligamentoplasty, are increasingly gaining interest to avoid adverse effects of spinal fusion, but literature addressing long-term results is sparse. A total of 56 consecutive patients who underwent Graf ligamentoplasty were reviewed at a minimum 10-year follow-up. Forty-three patients in the original cohort had sufficient clinical and radiographic follow-up for analysis. The pathologies included degenerative spondylolisthesis in 23 patients, disc herniation with flexion instability in 13 patients, spinal stenosis with flexion instability in 4 patients, and degenerative scoliosis in 3 patients. Single-level procedures were performed in 36 patients; multilevel procedures were performed in 7 patients. Radiographic and clinical assessments were performed before surgery and at the final follow-up. Disability due to low back pain and/or sciatic symptoms was significantly improved in the patients with degenerative spondylolisthesis or flexion instability. However, degenerative scoliosis and/or laterolisthesis were associated with poor clinical improvement. In radiographic assessment, segmental lordosis was maintained in 10.9 degrees, and flexion-extension motion was averaged 3.6 degrees at the final follow-up. Facet arthrodesis eventually occurred in 14 patients (32.6%) at an average of 82 months after surgery. Additional surgeries were required in 3 patients (7.0%) for adjacent segment pathologies. The long-term results showed that Graf ligamentoplasty is an effective treatment option for low-grade degenerative spondylolisthesis and flexion instability. However, this procedure has limitations to correct spinal deformity, and is not advocated for the treatment of degenerative scoliosis and laterolisthesis.