Risk factors for early failure of surgical amputations: An analysis of 8,878 isolated lower extremity amputation procedures

Background: There are very few data currently published on risk factors for early failure of lower extremity amputation procedures. Study Design: All patients from the 2005-2010 American College of Surgeons NSQIP database who underwent isolated lower extremity amputation were included for analysis (excluding patients with earlier operation within 30 days, patients undergoing an open amputation, and patients undergoing another procedure during amputation). Multivariate logistic regression was used to determine predictors of early amputation failure (defined as need for reoperation within 30 days postoperatively) after adjustment for a number of preoperative and intraoperative variables. Results: A total of 8,878 patients were included for analysis (4,258 below-knee amputations [BKA]; 3,415 above-knee amputations; and 1,205 transmetatarsal amputations). Overall rate of early amputation failure was 12.7% (12.6% for BKA, 8.1% for above-knee amputations, and 26.4% for transmetatarsal amputations; p < 0.0001). Several pre- and intraoperative variables appeared to be independently associated with early amputation failure, including emergency operation, transmetatarsal amputation (reference = BKA), sepsis (reference = no sepsis), septic shock (reference = no sepsis), end-stage renal disease, systemic inflammatory response syndrome (reference = no sepsis), intraoperative surgical trainee participation, body mass index ≥30, and ongoing tobacco use. Characteristics associated with decreased early amputation failure include age 80 years or older (reference = younger than 65 years), locoregional anesthesia, above-knee amputation (reference = BKA), operative time 40 to 59 minutes (reference = <40 minutes), operative time ≥80 minutes (reference = <40 minutes), and operative time 60 to 79 minutes (reference = <40 minutes). Conclusions: Increased operative time and heightened supervision of participating surgical trainees can decrease the risk of early amputation failure. In addition, specific clinical situations, such as sepsis or emergency procedures, should prompt vascular surgeons to consider either an open amputation procedure or a more proximal closed amputation.