# Preoperative Epidural Steroid Injections and Surgical Site Infection Risk in Lumbar Spine Surgery: A Retrospective Cohort Study

## TL;DR

This study found that the timing of preoperative epidural steroid injections does not affect surgical site infection risk in lumbar spine surgery.

## Contribution

The study provides new evidence that ESI timing is not a significant risk factor for SSIs in lumbar spine surgery.

## Key findings

- No significant difference in SSI rates was found between early and late ESI groups.
- Higher BMI, DMARD use, and higher ASA scores were associated with increased SSI risk.

## Abstract

Background: Low back pain is a leading cause of work-related disability worldwide. Epidural steroid injections (ESIs) are commonly used as nonoperative treatments for patients with degenerative lumbar spine pathology. It is imperative to further elucidate the association between preoperative ESIs and postoperative outcomes in this population. This study seeks to evaluate the association between the timing of preoperative ESIs and the incidence of surgical site infections (SSIs) in patients undergoing lumbar spine surgery.

Methods: This retrospective study analyzed patients who underwent lumbar spine surgery from January 2020 to December 2021. Patients were stratified based on ESI status: no ESI, most recent ESI within three months preoperatively (early group), and most recent ESI equal to or greater than three months preoperatively (late group). All patients were followed for at least one year postoperatively to monitor for SSI. Bivariate correlation analysis using Spearman’s rank correlation coefficient was performed to identify risk factors for SSI. Infection rates across ESI groups were compared using Pearson’s chi-square test, Fisher’s exact test, or the chi-square test of independence, selected based on sample size and expected cell counts.

Results: Among 94 patients, 49 received a preoperative ESI. Of these, 11 patients were in the early ESI group and 38 in the late ESI group. The overall infection rate was 2.2%, with one infection in each ESI subgroup. No significant difference in SSI rates was observed between the early and late ESI groups (p=0.171). Higher BMI, use of Disease-Modifying Antirheumatic Drugs (DMARDs), and higher American Society of Anesthesiologists (ASA) scores were associated with an increased SSI risk (p<0.05).

Conclusions: The timing of preoperative ESI does not significantly influence SSI risk in lumbar spine surgery. This study also highlights the role of elevated BMI, DMARD use, and ASA scores as potential risk factors for SSI in patients receiving preoperative ESI. Mitigating infection risk should focus on addressing modifiable factors such as BMI, DMARD use, and ASA scores rather than ESI timing.