The initial learning and supply cost curve of incorporating interlaminar and transforaminal endoscopy at a tertiary academic medical center

Introduction: Spinal endoscopy is technically challenging with an unclear learning curve. We sought to describe the initial learning and supply cost curve for a surgeon who incorporated interlaminar and transforaminal endoscopy at a tertiary academic medical center.

Methods: A retrospective review of interlaminar and transforaminal cases was conducted from first case performed 11/16/21 to 5/5/23. Linear regressions were performed assessing effect of experience on operative time, intra-op x-ray utilization, and surgical supply cost.

Results: Average age was 59±18, BMI 30±6, EBL 11±10cc. Eight-two % of interlaminar cases and 100% of transforaminal cases were discharged home. Forty-one interlaminar cases and 15 transforaminal cases were performed. For interlaminar cases, regression for operative time (t) determined by case number (x) was t = 213min - 0.9x, p = 0.29. Xray utilization (f) was f = 61 - 0.9x, p < 0.01. Supply cost (c) was c = $1,084 + $6x, p = 0.27. For the transforaminal cases, t = 236min - 3x, p = 0.6, f = 171 – 8.7x, p = 0.12, and c = $2,402 - $34x, p = 0.63. Surgical time per decompressed level was overall similar between interlaminar vs transforaminal (194min ± 59 vs 213 ± 80, respectively, p = 0.18). Xray utilization was significantly lower for the interlaminar than transforaminal approach (43 ± 23 vs 105 ± 63, respectively, p < 0.001). Supply cost per decompressed level was significantly cheaper for the interlaminar approach than the transforaminal ($1219 ± 393 vs $2090 ± 978, respectively, p < .001).

Conclusion : The learning curve for spinal endoscopy is steep. Experience led to significantly reduced intra-operative x-ray utilization, a trend towards reduced intra-operative time, but similar surgical supply costs. Supply cost per decompressed level and x-ray utilization were significantly cheaper for the interlaminar approach than the transforaminal, however time per decompressed level appeared similar.