PALM BEACH, FLA. – Locoregional anesthesia boosts the success rate of lower-extremity amputations, while time-saving shortcuts and relying too heavily on surgical residents to perform the surgery raise the risk that an amputation patient will run into problems following surgery, according to a review of nearly 9,000 U.S. patients.
Based on these findings, "we use locoregional anesthesia when possible," and focus on "careful and meticulous handling of tissue," Dr. P. Joshua O’Brien said at the annual meeting of the Southern Surgical Association. "This is the first paper to suggest that locoregional anesthesia may have a protective effect and improve outcomes."
The study results also made Dr. O’Brien and his colleagues at Duke University in Durham, N.C., more aware that amputations "are an important procedure" even though they are often a "junior-level case frequently overseen by a senior resident." The study results prompted Duke attending surgeons to maintain "careful observation of the residents until they feel comfortable that they [the residents] adequately understand the art of performing an amputation," said Dr. O’Brien, a vascular surgeon at Duke.
The analysis he and his associates performed used data collected during 2005-2010 by the National Surgical Quality Improvement Program of the American College of Surgeons. The study included patients who underwent an above-the-knee amputation (3,415 patients – 38%), a below-the-knee amputation (4,258 patients – 48%), or a transmetatarsal amputation (1,205 patients – 14%), but excluded patients who had another surgical procedure with their amputation, prior surgery within 30 days of the amputation, a preoperative do-not-resuscitate order, or missing data; 63% of all the amputation patients had diabetes.
During 30-day postsurgical follow-up, the overall rate of amputation failure was 13%, death occurred in 7%, wound complications affected 9%, and nonwound complications affected 21%. The patients averaged a 6-day postsurgical hospital length of stay.
Early amputation failure showed a statistically significant link with the type of amputation. Patients with a transmetatarsal amputation had a 26% early failure rate, those who underwent a below-the-knee procedure had a 13% failure rate, while above-the-knee amputations failed 8% of the time.
In a multivariate analysis that controlled for patient- and procedure-related factors, several variables linked with statistically significant increases or decreases in the rate of amputation failure. Notable among the factors that increased failure rates were emergency surgery, which boosted the failure rate 2.2-fold compared with nonemergency surgery, and participation of a surgical trainee, which raised the rate 37% compared with the rate when no trainee participated. Trainee participation was common, occurring in 59% of the 8,878 amputations included in the analysis.
Among the factors significantly linked with a reduced rate of amputation failures were use of locoregional anesthesia, which cut the failure rate by 25% compared with general anesthesia, and operative times of at least 40 minutes, which cut failure rates compared with surgery times of less than 40 minutes. The lowest failure rates occurred when the duration of amputation surgery lasted at least 60 minutes. Among patients included in the study, 20% received locoregional anesthesia.
The results also highlighted the important association of amputation failure with other measures of poor surgical outcomes in these amputation patients. Patients who developed amputation failure within 30 days of their surgery also had a nearly sevenfold increased rate of wound complications, and a twofold increased rate of nonwound complications; the average hospital length of stay was 10 days compared with 5 days among patients without amputation. Amputation failure had no significant impact on postoperative mortality, Dr. O’Brien said.
He said he had no relevant financial disclosures.
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