Cefazolin Alone Versus Cefazolin with Tobramycin or Gentamicin as Intraoperative Antibiotic Prophylaxis for Single-Level Posterior Lumbar Fusion

Introduction: Surgical site infection (SSI) is a rare but serious complication of lumbar fusion. Determining an optimal antibiotic prophylaxis regimen to minimize its incidence is critical. Methods: Adult single-level posterior lumbar fusion (PLF) patients were identified from the 2010 to October 2021 PearlDiver M157 database, excluding those with infectious, neoplastic, or traumatic diagnoses in the 90 days preoperatively or inactivity in 90 days postoperatively. Intraoperative antibiotic prophylaxis regimens were determined using the Current Procedural Terminology J-codes. Two cohorts were created: (1) patients who received cefazolin alone and (2) patients who received cefazolin and either tobramycin or gentamicin. Differences in age, sex, and Elixhauser Comorbidity Index (ECI) and 90-day postoperative adverse outcomes and 2-year revision rates were assessed with univariable analysis and multivariable logistic regression controlling for patient age, sex, and ECI. Results: Of 8,161 PLF patients, 7,562 (92.7%) received cefazolin for perioperative antibiotic prophylaxis and 599 (7.3%) received cefazolin and gentamicin/tobramycin. Antibiotic subgroups did not vary in age, sex, or ECI (P > 0.05 for all). On univariable and multivariable analyses, no 90-day outcomes, nor 2-year revision rates varied significantly between the antibiotic prophylaxis subgroups (P > 0.05 for all). Discussion: For single-level PLF, cefazolin alone versus cefazolin and gentamicin/tobramycin did not differ in rates of 90-day adverse outcomes or 2-year revisions.