OBJECTIVE: This study examined whether prior lumbar laminectomy or fusion at overlapping levels affects outcomes after long-segment thoracolumbar fusion for ASD.
SUMMARY OF BACKGROUND DATA: Adult spinal deformity (ASD) from age-related degeneration is increasing with an aging population. Long-segment thoracolumbar fusion is an option for adults with severe deformity or misalignment, but prior lumbar surgery may increase operative complexity and prolong recovery.
METHODS: We reviewed 219 adults undergoing ≥4-level thoracolumbar fusion for ASD (2016-2021), grouped by prior overlapping fusion (n=65), laminectomy alone (n=36), or no lumbar surgery (n=118). The primary outcome was time to revision, evaluated using Kaplan-Meier and adjusted Cox analyses. Secondary outcomes were complications and change in Oswestry Disability Index (ODI) among patients with paired scores and ≥6 months of follow-up.
RESULTS: Patients with prior lumbar fusion more frequently presented with sagittal deformity or mechanical failure, lower median Cobb angle, and greater sagittal vertical axis than surgery-naïve patients. Revision-free survival differed significantly among groups (log-rank χ²=20.0, P<0.001). Prior lumbar fusion was independently associated with increased revision risk compared with no prior lumbar surgery (hazard ratio [HR], 2.93; 95% confidence interval [CI], 1.58-5.44; P<0.001), whereas prior laminectomy was not (HR, 0.55; 95% CI, 0.23-1.34; P=0.186). Among 174 patients with paired ODI scores, median ODI improvement was 14 points in surgery-naïve patients, 6 points after prior laminectomy, and 10 points after prior fusion (P=0.478). Minimum clinically important difference achievement did not differ among groups (52.2%, 40.7%, and 42.1%, respectively; P=0.376), nor did postoperative complication rates.
CONCLUSION: Prior overlapping lumbar fusion, but not prior laminectomy, was independently associated with greater revision risk after long-segment thoracolumbar fusion for ASD. Prior fusion and laminectomy should be considered separately during preoperative counseling and operative planning.
STUDY DESIGN: Retrospective Cohort Study.
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