Surgical outcome predictors in degenerative lumbar scoliosis (DLS)
We studied 58 patients with degenerative lumbar scoliosis followed 4 yrs showed clinical improvement (P=0.001) with surgical treatment. Only patients developing nonunion had poorer outcomes (P=0.001).
Surgery for DLS is complicated due to co-morbidities, stiff deformity, osteoporosis, and other factors. Identifying negative outcome predictors would improve patient selection.
A retrospective review of prospectively collected data on 58 consecutive patients with DLS, stenosis, and listhesis who underwent decompression and posterior instrumented deformity reduction and fusion at a single center and were followed 48 months (25-82 months). Average age: 68 years (49-80); 16 had previous surgery, 8 were smokers. Fusions averaged 7.4 levels (4-17 levels), 42 were fused to S1; all had interbody rhBMP-2 at 7.6mg/disc (2-12mg): 39 TLIF, 19 ALIF. Chief complaints: back pain-23, back and leg-29, gluteal pain–3, leg pain–1. Stenosis was present at average 3.4 levels. Outcomes included VAS, Oswestry (ODI), medication records, and full radiographic follow-up measuring scoliosis curve, sagittal T10-L2, lordosis T12-S1, coronal and sagittal balance, and pelvic incidence.
Most common complications: adjacent degeneration-22, fracture-7, nonunion-7. Patients had significant improvement surgery: VAS pre-6.4, 1 year-2.5, 2 year-3.2, (P=.001); ODI pre-50, 1 year-24.0, 2 year-29.6, (P=.001). Pain medication requirements dropped accordingly. The only predictor of inferior outcome was development of a nonunion (P=0.001). Not associated with outcome: Chief complaint (back pain, back and leg pain, weakness, imbalance), age, BMP dose, pre-op deformity severity, pre-op sagittal imbalance, fusion length, fusion to S1, correction achieved, co-morbidities, smoking, and all other complications. Curve correction averaged 68%.
Significant improvement is achievable in DLS surgery regardless of the specific surgical requirements, co-morbidities, clinical presentation, and complications except pseudarthrosis. Achieving a solid arthrodesis in DLS should be a high priority.