35 Years of Lower Extremity Take-Backs: Free Flap Type Influences Salvage Outcomes
John T. Stranix, MD, Adam Jacoby, MD, Lavinia Anzai, BS, Z-Hye Lee, MD, Pierre B. Saadeh, MD, Vishal D. Thanik, MD, Jamie P. Levine, MD.
Wyss Department of Plastic Surgery, NYU Langone Medical Center, New York, NY, USA.
Purpose: Free flaps for lower extremity trauma reconstruction have a notoriously high failure rate compared with other anatomic sites. In addition, the choice between fasciocutaneous and muscle-based flaps remains controversial: muscle flaps provide pliable bulk for elimination of dead space and may promote osseous union while fasciocutaneous flaps avoid muscle sacrifice, are more easily re-elevated, and may provide a superior aesthetic result. Considering the high incidence of lower extremity flap failure, we compared salvage rates after take-backs for vascular compromise between fasciocutaneous and muscle free flaps for lower extremity trauma reconstruction.
Methods: Retrospective institutional registry review of 2,898 free flaps performed between 1979-2016 identified 806 lower extremity reconstructions; 361 soft tissue flaps performed for Gustilo IIIB/C coverage met inclusion criteria. Patient demographics, injury mechanism/location, flap type, operative details, and peri-operative outcomes were evaluated. Complications, take-backs, and flap failure rates were compared between muscle and fasciocutaneous flaps using Chi-square and logistic regression. Bonferroni adjusted z tests were used to determine the association between sub-location of injury and flap type. Complication and take-back rates were additionally stratified by defect location and flap type to help eliminate confounding variables.
Results: Overall, muscle flaps predominated (n=287, 79.9%) compared to fasciocutaneous (n=74, 20.5%). Congruent with traditional reconstructive dogma, the distal third was most common defect location (55.5%); within this sub-location, a higher percentage of fasciocutaneous flaps were used (72.5% vs. 51.3%, p=0.016). Fasciocutaneous flaps had smaller mean surface area compared to muscle (205±115cm2 vs. 301±253cm2, p<0.001). Complications occurred in 143 flaps (39.8%) with 37 partial flap losses (10.3%), and 31 total flap losses (8.6%). Overall complication rates were comparable between muscle and fasciocutaneous flaps (43.5% vs. 39.4%, p=0.538). Partial flap losses were significantly more common among muscle flaps (12.1% vs. 4.1%, p=0.009), however, similar rates of total flap failure occurred in both groups (8.7% vs. 8.1%, p=0.772). Emergent return to the operating room for vascular compromise occurred in 45 flaps (12.4%) due to venous (n=26, 57.8%), arterial (n=14, 31.0%), or undetermined (n=5, 11.1%) causes. There was a trend towards earlier take-backs among fasciocutaneous flaps compared to muscle (1.93±2.5 vs. 3.97±4.8 days, p=0.072). Regression analysis controlling for age, sex, time since injury, number of veins, and flap size found a significantly higher take-back rates among fasciocutaneous flaps (n=15, 20.2%) compared to muscle (n=30, 10.5%) (RR=2.63, p=0.027). Despite higher take-back rates, however, additional regression analysis controlling for the same variables plus skin paddle presence demonstrated higher rates of successful flap salvage after take-backs among fasciocutaneous flaps (66.7%) compared to muscle (16.7%), (RR=13.03, p=0.038).
Conclusion: Compared to muscle, fasciocutaneous flaps demonstrated lower partial flap failure rates despite more frequent take-backs for vascular compromise. These findings are likely related to a combination of lower metabolic demand in fasciocutaneous tissue compared to muscle and easier visual recognition of vascular. Interestingly, this was independent of both flap size and skin paddle presence. In the context of higher failure rates among lower extremity trauma free flaps, our results suggest improved outcomes with fasciocutaneous tissue compared to muscle.
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