Sacrospinalis muscle-pedicle bone graft in posterolateral fusion for spondylolisthesis

Twenty three patients with lumbar spondylolisthesis (6 Grade I, 14 Grade II and 3 Grade III) with low back pain, and radicular pain in 14, were treated surgically when they failed to respond to conservative treatment. Their average age was 33.2 years. Bilateral posterolateral spinal fusions with autologous iliac bone chips, supplemented by a sacrospinalis muscle-pedicle bone graft on the left side, were undertaken after laminectomy and foraminotomy in all except in two adolescents, where laminectomy and foraminotomy were avoided. The period of follow-up varied from 26 to 126 months (average 65.3 months). The results in 11 (48%) patients were excellent, 9 (39%) were good, 2 (9%) fair and one (4%) poor. There was a higher incidence (87%) of good quality of osseous fusion on the left side, where the sacrospinalis muscle-pedicle bone graft was used, compared to the right, where 70% of fusions were satisfactory. Function improved in 91% of the patients. Neither scoliosis nor weakness of the extensor muscles of the back developed due to reanchorage of the sacrospinalis muscle to the lumbosacral spines.