Increasing Nonconcurrent Overlapping Surgery Is Not Associated With Outcome Changes in Lumbar Fusion

There remains a paucity of literature on the impact of overlap on neurosurgical patient outcomes. The purpose of the present study was to correlate increasing duration of surgical overlap with short-term patient outcomes following lumbar fusion. The present study retrospectively analyzed 1302 adult patients undergoing overlapping, single-level, posterior-only lumbar fusion within a single, multicenter, academic health system. Recorded outcomes included 30-day emergency department visits, readmission, reoperation, mortality, overall morbidity, and overall morbidity/surgical complications. The amount of overlap was calculated as a percentage of total overlap time. Comparison was made between patients with the most (top 10%) and least (bottom 40%) amount of overlap. Patients were then exact matched on key demographic factors but not by the attending surgeons. Subsequently, patients were exact matched by both demographic data and the attending surgeons. Univariate analysis was first carried out prior to matching and then on both the demographic-matched and surgeon-matched cohorts. Significance for all analyses was set at a value of