Clinical and functional outcome patterns long term after deformity correction: Degenerative lumbar scoliosis vs. adult idiopathic scoliosis

2012

Background

The value of spine surgery is increasingly being scrutinized, both for Medicare and pre-Medicare patients. Most series of adult scoliosis outcomes focus on younger patients and do not distinguish de novo degenerative lumbar scoliosis (DLS) from adult idiopathic scoliosis (IS). A direct comparison of DLS vs IS outcomes has not been done, to identify clinical and functional outcome differences over time.

Purpose

To define the differences in complications and long-term clinical, functional, and radiographic outcome patterns after surgical correction of DLS vs IS.

Study Design

Retrospective review of prospectively collected clinical and radiographic data

Patient Sample

121 consecutive adults who underwent posterior instrumented spinal fusion

Outcome measures Visual analog pain scores (VAS), Oswestry disability index (ODI), pain medication records, and complications recorded preop, 1 year, 2 years, and latest follow-up. Complication rates were evaluated using Fisher's exact test. The effect of diagnosis as well as number of levels fused on VAS and Oswestry (ODI) outcomes were evaluated with a linear regression.

Methods

All patients underwent primary posterior spinal fusion for DLS (68 patients, age 68) or IS (53 patients with T/TL/L/Double curves, age 54). Fusion length: DLS- 7.7 levels (4-9), IS-10.9 levels (7-17). Anterior fusion: DLS-17, IS-23. Excluded: revision surgery, congenital and neuromuscular scoliosis. Average age 62 years (19-90 years). Radiograph measurements: curve, coronal/sagittal balance, sagittal: T5-12, T10-L2, T12-S1, pelvic incidence.

Results

Follow-up averaged 67 months (25-110 months). DLS had more complications than IS though not statistically significant: Infection: DLS-4, IS-0; Nonunion: DLS-7, IS-3; Adjacent fracture; DLS-3, IS-1; Revision fusion: DLS-15, IS-11. Both groups improved clinically. VAS: DLS-preop-6.1, 1 year-2.5, 2 year-3.4, 5 year-4.2; IS-preop-5.1, 1year-2.2, 2 year-2.2, 5 year-2.7. ODI: DLS-preop-50.8, 1 year-25.2, 2 year-31.8, 5 year-33.7; IS-preop-37.2, 1 year-19, 2 year-22.0, 5 year-23.2. Curve correction also improved in both groups: DLS-preop-31, 2 year-11 (63%); IS-57, 2 year-19 (67%). Lordosis: DLS-preop-39, 2 year-45. Both groups show significant (alpha <0.05) improvement in VAS and ODI between 0 and 2 years.

Conclusions

Both DLS and IS adults improved clinically and maintained improvement long-term, despite DLS patients being older and having more preop pain. DLS patients showed gradual degradation of initial postop outcomes over until plateau at 3–4 years. Complications are somewhat more common in the older DLS group (more osteoporosis, arthritis, fusions to sacrum) though need for revision surgery was similar in both groups.

Surgery for DLS results in a different natural history postop compared to surgery for IS. Beneficial outcomes are achieved in both groups, and maintained long-term.