Patients undergoing overlapping posterior single-level lumbar fusion are not at greater risk for adverse 90-day outcomes

Objective: This study evaluated overlapping surgery on long-term outcomes following elective, single-level lumbar fusion on exact matched patients undergoing surgery with or without overlap. Patients and Methods: 3799 consecutive adult patients undergoing single-level, posterior-only lumbar fusion over a six-year period at a multi-hospital university health system were retrospectively followed. Reported outcomes included reoperation, emergency department (ED) visit, readmission, overall morbidity and mortality in the 90 days following surgery. Coarsened Exact Matching was used to match patients with and without overlap on key demographic factors. Patients were subsequently matched by both demographic data and by the attending surgeon performing the operation. Univariate analysis was carried out on the whole population, the demographic matched cohort, and demographic and surgeon matched cohort, with significance set at a p-value < 0.05. Results: Patients with overlap had a longer duration of surgery and were less likely to have an ED visit within 90 days of surgery (p < 0.03) but had no other significant differences. Within the demographic matched cohort and demographic/surgeon matched cohort, there was no significant difference in age, gender, history of prior surgery, ASA score, or CCI score, but patients with overlap had a longer duration of surgery (p < 0.01). Patients did not have significant differences with respect to any morbidity or mortality outcome in either the demographic or surgeon matched cohort. Conclusions: Patients undergoing overlapping, single-level lumbar fusion were not at greater risk of long-term morbidity or mortality, despite having a significantly longer duration of surgery.