# The Initial Learning and Supply Cost Curve of Incorporating Interlaminar and Transforaminal Endoscopy at a Tertiary Academic Medical Center

## TL;DR

This study examines how a surgeon's experience affects the time and cost of spinal endoscopy procedures at a medical center.

## Contribution

The paper provides empirical data on the learning and supply cost curves for interlaminar and transforaminal spinal endoscopy.

## Key findings

- The interlaminar approach had lower X-ray utilization and supply costs compared to the transforaminal approach.
- Experience reduced X-ray use and showed a trend toward shorter operative times.
- Surgical outcomes were similar before and after surgeons reached a familiarity cutoff point.

## Abstract

Introduction

Spinal endoscopy is challenging with a steep learning curve and an unclear supply cost curve. We describe the initial learning and supply cost curves for a surgeon who incorporated interlaminar and transforaminal endoscopy.

Methods

Interlaminar and transforaminal cases performed between November 2021 and May 2023 were retrospectively reviewed. Linear regressions were used to assess the effect of experience on operative time, intraoperative X-ray utilization, and surgical supply costs. Trends were assessed using a cumulative running median analysis to determine a cutoff point for surgeon familiarity.

Results

A total of 56 patients were included (41 interlaminar and 15 transforaminal). Surgical time per decompressed level was similar (192 minutes ± 60.9 vs. 213 minutes ± 80, P = 0.3). Transforaminal cases had greater X-ray utilization (42.7 images ± 23.5 vs. 105.4 images ± 63.3, P < 0.01) and supply cost ($1,223 ± 389 vs. $2,090 ± 978, P < 0.01). Cutoff points for familiarity were earlier in the interlaminar group in X-ray use (nine cases vs. 11) and supply cost (two cases vs. 11). Both approaches had the same operative time cutoff in three cases. Differences did not result in significantly different surgical complications, disposition, or revision rates.

Conclusion

The learning curve for spinal endoscopy is non-negligible. The supply cost per decompressed level and X-ray utilization were cheaper for the interlaminar approach. Time per decompressed level appeared similar. Experience led to significantly reduced intraoperative X-ray utilization, a trend towards reduced intraoperative time, and stable supply costs. Cutoff points to familiarity were earlier in the interlaminar group, but surgical outcomes were similar pre- and post-cutoff.