# Cefazolin prophylaxis is associated with lower surgical site infection risk than vancomycin following elective spine surgery

## TL;DR

Using cefazolin instead of vancomycin before spine surgery reduces the risk of surgical site infections, according to a large study.

## Contribution

This study provides large-scale evidence that cefazolin is more effective than vancomycin in preventing surgical site infections after spine surgery.

## Key findings

- Cefazolin was associated with significantly lower SSI risk in TLIF/PLIF and microdiscectomy procedures.
- Cefazolin showed comparable or lower SSI risk than vancomycin across all spine surgery types.
- The study supports cefazolin as the preferred antibiotic for spine surgery when no allergy is present.

## Abstract

Surgical site infection (SSI) remains a major cause of morbidity following elective spine surgery, with incidence rates up to 3%. Current guidelines recommend cefazolin as the first-line prophylactic antibiotic due to its efficacy against methicillin-sensitive Staphylococcus aureus (MSSA) and coagulase-negative staphylococci (CoNS). However, reported B-lactam allergies are commonly cited in clinical practice as a reason for substitution with vancomycin, which provides inferior coverage for MSSA and limited gram-negative activity. Prior single center studies suggest higher SSI risk with vancomycin, but large-scale evidence remains limited.

A retrospective cohort analysis was conducted using the TriNetX US Collaborative Network (2015-2023). Adults undergoing elective spine surgery, including transforaminal or posterior interbody fusion (TLIF/PLIF), multilevel lumbar fusion, posterior cervical fusion, anterior cervical discectomy and fusions (ACDF), and microdiscectomy, were identified. Patients receiving perioperative cefazolin or vancomycin within 24 hours of surgery were included. 1:1 propensity score matching controlled for demographics, comorbidities, and infection risk factors. The primary outcome was 90-day SSI, assessed using ICD-10 diagnosis codes. Risk ratios (RR) were estimated using Cox proportional hazards models.

After matching, 12,996 patients were included across 5 procedure cohorts. Cefazolin prophylaxis was associated with lower or comparable SSI risk compared with vancomycin across all procedures. Statistically significant differences were observed for TLIF/PLIF (0.82% vs. 2.30%; RR 0.36, 95% CI 0.18–0.7; p = .0019) and microdiscectomy (0.34% vs. 0.69%; RR 0.50, 95% CI 0.27–0.93; p = .025). Nonsignificant trends favored cefazolin for posterior cervical fusion (0.88% vs. 1.41%), multilevel lumbar fusion (1.25% vs. 1.51%), and ACDF (0.30% vs. 0.54%).

Cefazolin prophylaxis is associated with significantly lower SSI risk in elective spine procedures. These findings support cefazolin as the preferred perioperative antibiotic and emphasize the need for accurate B-lactam allergy assessment to optimize infection prevention and antimicrobial stewardship in spine surgery.