Overlap Before the Critical Step of Lumbar Fusion Does Not Lead to Increased Short-Term Morbidity

Few studies have assessed the impact of overlapping surgery during different timepoints of neurosurgical procedures.

To evaluate the impact of overlap before the critical portion of surgery on short-term patient outcomes following lumbar fusion.

In total, 3799 consecutive patients who underwent single-level, posterior-only lumbar fusion over 6 yr (2013-2019) at an academic hospital system were retrospectively studied. Outcomes included 30-d emergency department (ED) visit, readmission, reoperation, mortality, overall morbidity, and overall morbidity/surgical complications. Duration of overlap that occurred before the critical portion of surgery was calculated as a percentage of total beginning operative time. Univariate logistic regression was used to assess the impact of incremental 1% increases in the duration of overlap within the whole population and patients with beginning overlap. Subsequently, univariate analysis was used to compare exact matched patients with the least (bottom 40%) and most amounts of overlap (100% beginning overlap). Coarsened exact matching was used to match patients on key demographic factors, as well as attending surgeon. Significance was set at a P-value < .05.

Increased duration of beginning overlap was associated with a decrease in 30-d ED visit (P = .03) within all patients with beginning overlap, but not within the whole population undergoing lumbar fusion. Duration of beginning overlap was not associated with any other short-term morbidity or mortality outcome in either the whole population or patients with beginning overlap.

Increased duration of overlap before the critical step of surgery does not predict adverse short-term outcomes after single-level, posterior-only lumbar fusion.