Pelvic Incidence-Lumbar Lordosis Mismatch Is Not Associated with Early Reoperation for Adjacent Segment Disease After Lumbar Fusion.

ABSTRACT

OBJECTIVE: To compare the 2-year reoperation rates for adjacent segment disease between patients with pelvic incidence-lumbar lordosis (PI-LL) mismatch postoperatively and patients with normal PI-LL measurements. METHODS: Patients undergoing elective 1- to 2-level lumbar fusion for degenerative conditions between 2016 and 2018 were retrospectively reviewed. Spinopelvic radiographic parameters immediately postoperation were measured, and PI-LL mismatch was determined using the age-adjusted thresholds defined in Lafage et al. After propensity score matching, early reoperation rates were compared between the PI-LL mismatch and normal PI-LL cohorts. Early reoperation was defined as symptomatic adjacent segment disease (ASD) requiring reoperation within 2 years of the index surgery. RESULTS: A total of 219 patients were identified. The average age was 59 years of age, with 59.8% female. The PI-LL mismatch cohort (n = 148) was younger (57.5 vs. 63.5 years, P < 0.001) and had a higher proportion of Black patients (31.8% vs. 11.3%, P = 0.001) than the normal PI-LL cohort, respectively. A total of 100 patients in the PI-LL mismatch cohort were propensity score matched to 66 patients in the normal PI-LL cohort, resulting in no difference in age (P = 0.177), sex (P = 0.302), race (P = 0.727), or body mass index (P = 0.892). Using these matched cohorts, the rate of early reoperation for ASD was 8.0% in the PI-LL mismatch cohort and 9.1% in the normal PI-LL cohort (P = 0.805), with a mean time to reoperation of 1.28 and 1.33 years, respectively. CONCLUSIONS: After propensity score matching, PI-LL mismatch was not associated with early reoperation for ASD in patients undergoing 1- to 2-level lumbar fusions for degenerative conditions.