Postoperative Antibiotics Confer No Protective Association After Fat Grafting for Breast Reconstruction
Authors: Thawanyarat Kometh , Johnstone Thomas , Rowley Mallory , Kim Trudy , Francis Shannon , Barrera Janos , Cheeseborough Jennifer , Sheckter Clifford , Nazerali Rahim 
Published: March 2023

Introduction
Autologous fat grafting after breast reconstruction is a commonly used technique to address asymmetry and irregularities in breast contour. While many studies have attempted to optimize patient outcomes after fat grafting, a key postoperative protocol that lacks consensus is the optimal use of perioperative and postoperative antibiotics. Reports suggest that complication rates for fat grafting are low relative to rates after reconstruction and have been shown to not be correlated to antibiotic protocol. Studies have additionally demonstrated that the use of prolonged prophylactic antibiotics do not lower the complication rates, stressing the need for a more conservative, standardized antibiotic protocol. This study aims to identify the optimal use of perioperative and postoperative antibiotics that optimizes patient outcomes.

Methods
Patients in the Optum Clinformatics Data Mart who underwent all billable forms of breast reconstruction followed by fat grafting were identified via Current Procedural Terminology codes. Patients meeting inclusion criteria had an index reconstructive procedure at least 90 days before fat grafting. Data concerning these patient's demographics, comorbidities, breast reconstructions, perioperative and postoperative antibiotics, and outcomes were collected via querying relevant reports of Current Procedural Terminology; International Classification of Diseases, Ninth Revision; International Classification of Diseases, Tenth Revision; National Drug Code Directory, and Healthcare Common Procedure Coding System codes. Antibiotics were classified by type and temporal delivery: perioperatively or postoperatively. If a patient received postoperative antibiotics, the duration of antibiotic exposure was recorded. Outcomes analysis was limited to the 90-day postoperative period. Multivariable logistic regression was performed to ascertain the effects of age, coexisting conditions, reconstruction type (autologous or implant-based), perioperative antibiotic class, postoperative antibiotic class, and postoperative antibiotic duration on the likelihood of any common postoperative complication occurring. All statistical assumptions made by logistic regression were met successfully. Odds ratios and corresponding 95% confidence intervals were calculated.

Results
From more than 86 million longitudinal patient records between March 2004 and June 2019, our study population included 7456 unique records of reconstruction-fat grafting pairs, with 4661 of those pairs receiving some form of prophylactic antibiotics. Age, prior radiation, and perioperative antibiotic administration were consistent independent predictors of increased all-cause complication likelihood. However, administration of perioperative antibiotics approached a statistically significant protective association against infection likelihood. No postoperative antibiotics of any duration or class conferred a protective association against infections or all-cause complications.

Conclusions
This study provides national, claims-level support for antibiotic stewardship during and after fat grafting procedures. Postoperative antibiotics did not confer a protective benefit association against infection or all-cause complication likelihood, while administering perioperative antibiotics conferred a statistically significant increase in the likelihood that a patient experienced postoperative complication. However, perioperative antibiotics approach a significant protective association against postoperative infection likelihood, in line with current guidelines for infection prevention. These findings may encourage the adoption of more conservative postoperative prescription practices for clinicians who perform breast reconstruction, followed by fat grafting, reducing the nonindicated use of antibiotics.