Day-of-Free Tissue Transfer Qualitative Cultures Do Not Predict Limb Salvage Outcomes

Successful free tissue transfer is critical for lower extremity salvage in the chronic wound population. The rates of lower extremity free tissue transfer success lag behind those for other anatomical sites. The aim of this study was to evaluate whether positive qualitative day-of-free tissue transfer cultures or pathogen virulence negatively impacts short- and long-term outcomes of lower extremity free tissue transfer.

Between April of 2011 and January of 2018, 105 lower extremity free tissue transfer procedures were performed. Growth level and speciation were identified from qualitative cultures taken during free tissue transfer. The relationship between demographics, comorbidities, culture data, postoperative infection, free tissue transfer survival, and long-term limb salvage was examined using logistic regression.

The median Charlson Comorbidity Index was 3. Intraoperative free tissue transfer cultures were positive in 39.1 percent. Flap survival was 93.3 percent. Postoperative infection developed in 12.4 percent. The limb salvage rate was 81.0 percent. Positive culture was not significant for flap survival, postoperative infection, or amputation. Cultures positive for Enterococcus species had a significant relationship with flap success (OR, 0.08; p = 0.01) and amputation (OR, 7.32; p = 0.04). Insufficient antimicrobial coverage had a significant relationship with postoperative infection (OR, 6.56; p = 0.01) despite the lack of pathogen concordance. On multivariate analysis, postoperative infection (OR, 12.85; p < 0.01) and Charlson Comorbidity Index were predictive of eventual amputation (OR, 1.44; p = 0.01).

Positive day-of-free tissue transfer cultures, regardless of pathogen, had limited predictive value for short- and long-term outcomes of free tissue transfer in the authors' cohort. These findings call for a broader multicenter prospective analysis and consideration of health care-associated infections and their impact on limb salvage outcomes.

Risk, III.