What Is the Learning Curve for Lumbar Spine Surgery Under Spinal Anesthesia?

Spinal anesthesia (SA) is routinely used in obstetrics and orthopedic surgery but has not been widely adopted in lumbar spine surgery (LSS). One perceived barrier is the learning curve for the neurosurgical and anesthesia team associated with managing a patient in the prone position under SA.

A retrospective cohort of 34 LSS cases under SA at our institution was examined. Operative time, corrected operative time per level, and complications were analyzed. The learning curve was assessed using a curve-fit regression analysis.

Of patients, 62% were female, with mean (SD) age and body mass index of 60.7 (10.8) years and 29.9 (4.6) kg/m², respectively. The mean (SD) for each time segment was operating room arrival to incision 35.7 (8.1) minutes, total surgical time 100.4 (35.8) minutes, and procedure finish to operating room exit 3.4 (2.5) minutes. When the times were normalized to procedure type and analyzed sequentially, the mean (SD) slope of all trendlines was 0.003 (0.005) with correlation coefficients of R² = 0.0002-0.01, indicating no appreciable learning curve. Normalized postanesthesia care unit time was significantly shorter for overnight stay versus same-day discharge (0.64 vs. 1.36, P = 0.0005).

Our data demonstrate the lack of a learning curve when SA is implemented in LSS cases by an anesthetic team already familiar with SA techniques for other procedures. Importantly, the surgical team was already familiar with the minimally invasive surgery approaches used in conjunction with SA. This study highlights that the barriers to transitioning to SA for LSS may be fewer than perceived.