Laminectomy and fusion for degenerative disease vs spondylolisthesis: Is spondylolisthesis or instability necessary for a successful long-term outcome?
As insurance carriers increasingly turn to "evidence based guidelines" for authorizing arthrodesis, spondylolisthesis or instability must necessarily be present for fusion to be authorized.
This is the first long-term study of surgical outcomes comparing laminectomy and fusion in spondylolisthesis (S) vs. degenerative disease (D) without instability.
Retrospective review of prospectively collected clinical and radiographic data
267 consecutive adults (M-109, F-158) with back and leg pain and stenosis who underwent open laminectomy and instrumented fusion at 1 or 2 levels
Visual Analog pain Scores (VAS), Oswestry Disability Index (ODI), pain medication records.
All 267 patients underwent open laminectomy and posterior instrumented fusion at 1-2 levels (average 1.6 levels) and TLIF with a PEEK cage (average 1.4 levels); S group- 139 patients (includes isthmic and degenerative spondylolisthesis), D group- 128 patients (facet and disc degeneration only). Age averaged 59 years (24-91 years); 31 were smokers, 100 had prior surgery (D-71, S-29). Excluded: non-fusion surgery, fusion for back pain alone without stenosis, fusion >2 levels, tumor/trauma. Clinical, functional, and radiographic outcomes were recorded preop, 1 year, 2 years, latest follow up.
Follow up averaged 5 years (24-101 months). Complications were similar in both groups. D group complications: Nonunion-1, infection-3, additional surgery (fusion-20, lami-8); S group complications: Nonunion-0, invection-1, additional surgery (fusion-31, lami-9). Clinical improvement was significant in both groups. D group VAS: preop-6.6, 1 year-3.3, 2 year-3.7 (p<0.001); ODI: preop-53.1, 1 year-29.3, 2 years-32.1 (p<0.001). S group VAS: preop-5.8, 1 year-2.4, 2 years-2.8 (p<0.001); ODI: preop-46.6, 1 year-21.3, 2 years-23.9 (p<0.001). Considering primary surgery only, D group VAS: preop-6.5, 1 year-3.3, 2 years-3.3; ODI preop-51.2, 1 year-25.6, 2 years-28.5 (p<0.001). Pain medication use also decreased in both groups.
For patients with stenosis and back pain, the presence of spondylolisthesis or instability is not required for successful long-term outcome after arthrodesis. Insurance carrier policy of denying spinal fusion based purely on the absence of spondylolisthesis or instability appears unjustified.