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

Abstract

Study DesignRetrospective Cohort Study ObjectivesTo 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. MethodsPatients undergoing elective 1-to-2 level lumbar fusion for degenerative conditions between 2016-2018 were retrospectively reviewed. Spinopelvic radiographic parameters immediately post-operation were measured and PI-LL mismatch was determined using the age-adjusted thresholds defined in Lafage et al. Following 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. ResultsA total of 219 patients were identified. The average age was 59 years old with 59.8% female. The PI-LL mismatch cohort (N=148) were younger (57.5 vs. 63.5, p<0.001) and had a higher proportion of black patients (31.8% vs. 11.3%, p=0.001) compared to the normal PI-LL cohort. 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 BMI (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. ConclusionsAfter 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.