Single-dose versus 24-hour antibiotic prophylaxis in reduction mammaplasty

Authors: Veiga DF, Garcia ES, Veiga-Filho J, Fialho SV, Borges ASF, Dornelas GV, Machado AA, Arruda Felix GA, Ferreira LM

Affiliation: Universidade Federal de São Paulo, Brazil

Journal: Plastic and Reconstructive Surgery, September 2025

PMID: 40857697

Key takeaways

• In reduction mammaplasty, a single preoperative cefazolin dose was noninferior to a 24-hour regimen for 30-day superficial surgical-site infection (SSI).

• SSI occurred in 5.5% overall and did not differ between single-dose and 24-hour groups (4/73 vs 4/73; all superficial).

• Wound dehiscence rates were similar (16/73 vs 14/73; P = 0.682), suggesting no wound-healing benefit from extended prophylaxis.

• Findings support antimicrobial stewardship: avoid routine postoperative antibiotics beyond induction for straightforward reductions (Level of Evidence I).

Background

Reduction mammaplasty reliably improves symptoms of macromastia. Postoperative infections are uncommon but drive morbidity and reoperations. Practice varies widely regarding antibiotic duration; many surgeons extend prophylaxis for 24 hours or longer despite limited evidence of benefit.

Objective

To determine whether 24 hours of cefazolin prophylaxis reduces 30-day SSI compared with a single induction dose in patients undergoing reduction mammaplasty.

Methods

• Design: Randomized, noninferiority, parallel-arm clinical trial (1:1 allocation).

• Setting: Academic centers in Brazil.

• Participants: 146 women undergoing bilateral reduction mammaplasty.

• Interventions:

  • Single-dose group: cefazolin 1 g IV at anesthesia induction only.

  • 24-hour group: cefazolin 1 g IV at induction, then every 6 hours for 24 hours.

  • No antibiotics were given after 24 hours in either arm.

• Endpoints:

  • Primary: 30-day SSI per CDC definitions (assessed weekly by a surgeon blinded to allocation).

  • Secondary: Wound dehiscence and other wound complications.

• Population profile: median age 33 years; median BMI 25.2 kg/m²; median excised tissue 925 g; median operative time 220 minutes.

Results

• Infections: 8/146 (5.5%) had SSI; 4/73 vs 4/73 (single-dose vs 24-hour), P = 1.000; all were superficial incisional.

• Dehiscence: 30/146 (20.5%); 16/73 vs 14/73, P = 0.682.

• Groups were similar in baseline characteristics; no signal that extended prophylaxis improved any measured outcome.

Conclusion

For reduction mammaplasty, extending prophylaxis beyond a single preoperative dose offers no advantage for preventing SSI or dehiscence. A single-dose regimen is sufficient for routine cases.

Strengths

• Randomized design with blinded outcome assessment and standardized CDC SSI definitions.

• Prospective weekly follow-up to 30 days.

Limitations

• Noninferiority margin and power calculations not detailed in the text available; small absolute number of SSIs may limit precision for rare deep/organ-space infections.

• All infections were superficial; study not powered for deep SSI or reoperation.

• Antibiotic regimen limited to cefazolin; external validity may vary with different flora, MRSA prevalence, or beta-lactam allergies.

• Cohort skewed toward young, normal-weight patients (median BMI 25.2), potentially limiting generalizability to higher-risk populations (obesity, diabetes, smokers, massive resections).

Clinical relevance

For healthy patients undergoing standard reduction mammaplasty, prescribe only a single preoperative cefazolin dose (weight-based per institutional policy), with no routine postoperative antibiotics. Reserve extended coverage for specific indications (e.g., gross contamination, prolonged unplanned re-entry, beta-lactam allergy with alternative agents, or institution-specific resistant organism risks) rather than as a blanket practice. Incorporate this into ERAS and stewardship pathways.

Critiques and questions

• Risk stratification: Outcomes are reported for the overall cohort. Were a priori subgroups (e.g., smokers, BMI ≥30, resection weight >1 kg/breast, long operative time) examined for interaction? These are the patients for whom some surgeons still extend prophylaxis.

• Drain use and wound care protocols: Did drain use or placement, resection weight, or T-junction management differ between groups? Such factors influence dehiscence (20.5% here) and might overshadow any marginal antibiotic effect.

• Microbiology and rescue therapy: What organisms were cultured from SSIs, and did resistance patterns differ? Time to diagnosis and response to standard oral therapy would contextualize the clinical impact of superficial SSI.