# Early Discontinuation of Prophylactic Antibiotics Is Not Associated with Increased Surgical Site Infection Risk in Spine Surgery: A Nationwide Cohort Study

## TL;DR

Stopping antibiotics within 24 hours after spine surgery does not increase infection risk, while longer use may raise it.

## Contribution

Nationwide data shows early antibiotic discontinuation in spine surgery is safe and reduces infection risk.

## Key findings

- Early antibiotic discontinuation (<24 h) was linked to lower surgical site infection rates.
- Prolonged antibiotic use (≥24 h) increased odds of surgical and non-surgical site infections.
- Results support guidelines limiting prophylactic antibiotics to 24 hours in spine surgery.

## Abstract

Background/Objectives: Surgical site infection (SSI) remains a significant complication following spine surgery, yet the optimal duration of prophylactic antibiotic administration remains debated. We investigated the association between prophylactic antibiotic duration and SSI rates following spine surgery using a nationwide claims database. Methods: This retrospective cohort study analyzed data from the Health Insurance Review and Assessment Service quality assessment database across four assessment waves (2014–2020, sixth to ninth). Adult patients (aged ≥19 years) undergoing elective spine surgery (decompression, instrumented fusion, vertebroplasty, or kyphoplasty) were categorized into two groups based on prophylactic antibiotic duration: <24 h or ≥24 h. Surgery type was the primary surgical categorization, while surgery site (cervical, thoracic, lumbar) was assessed separately in supplemental analyses. Primary outcomes included SSI, non-surgical-site infections, and total postoperative infections within 3 months. Multivariable logistic regression was performed to identify independent predictors of infection. Results: Of 82,840 patients included, 19,988 (24.1%) discontinued prophylactic antibiotics within 24 h and 62,852 (75.9%) continued antibiotics for ≥24 h. The <24 h group demonstrated significantly lower SSI rates compared to the ≥24 h group (0.16% vs. 1.47%, p < 0.05). After adjustment for confounders, prolonged antibiotic prophylaxis (≥24 h) was associated with increased odds of SSI (adjusted odds ratio [aOR] = 10.73, 95% CI = 7.30–15.79), non-surgical-site infections (aOR = 16.06, 95% CI = 13.11–19.67), and total postoperative infections (aOR = 17.82, 95% CI = 14.83–21.42). Conclusions: In this nationwide cohort, early discontinuation of prophylactic antibiotics within 24 h was not associated with increased SSI risk. Prolonged antibiotic prophylaxis beyond 24 h was associated with higher SSI rates, although confounding by indication likely contributed to this finding. These results are consistent with current guideline recommendations for limiting prophylactic antibiotic duration to 24 h or less in routine spine surgery, while recognizing that individualized approaches may be warranted in some high-risk patients.