Obesity and Lower Extremity Reconstruction: Evaluating Body Mass Index as an Independent Risk Factor for Early Complications

Abstract

Background The prevalence of obesity in the United States continues to grow and is estimated to affect over a quarter of the working-age population. Some studies have identified obesity as a risk factor for flap failure and complications in free flap-based breast reconstruction, but its clinical significance is less clear in nonbreast reconstruction. The role of obesity as a risk factor for failure and complications following lower extremity reconstruction has not been well described, and the limited existing literature demonstrates conflicting results. Methods The American College of Surgeons National Surgical Quality Improvement Program database was reviewed to identify patients undergoing local- or free-flap reconstruction of the lower extremity between 2010 and 2015. Preoperative variables and outcomes were compared between obese (body mass index ≥ 30) and nonobese patients. Chi-square analysis and Fisher's exact test were used for categorical variables and t-tests for continuous variables. Multivariate regression was performed to control for confounders. Results Univariate analysis of medical and surgical outcomes revealed that obese patients undergoing local flaps of the lower extremity required a significantly longer operative time (187.7 ± 123.2 vs. 166.2 ± 111.7 minutes; p = 0.003) and had significantly higher rates of superficial surgical site infection (SSI; 7.2% vs. 4.5%; p = 0.04). On univariate analysis, there were no significant differences in any postoperative outcomes between obese and nonobese patients undergoing microvascular free flaps of the lower extremity.On multivariate regression analysis, obesity was not an independent risk factor for superficial SSI (odds ratio = 1.01, p = 0.98) or increased operative time (β = 16.01, p = 0.14) for local flaps of the lower extremity. Conclusion Evaluation of a large, multicenter, validated and risk-adjusted nationwide cohort demonstrated that obesity is not an independent risk factor for early complications following lower extremity reconstruction, suggesting that these procedures may be performed safely in the obese patient population.

Stratification of Surgical Risk in DIEP Breast Reconstruction Based on Classification of Obesity

“…65 Additionally, many studies have documented obesity's role in increasing arterial caliber in response to the increased perfusion and nutrient needs of the larger tissue mass. [66][67][68][69][70] While imaging studies of deep inferior epigastric artery perforators have not found universal increases in perforator diameter among obese patients, [70][71][72] anecdotal intraoperative observations continue to support this in many reports. 55,59,70 Furthermore, other studies have suggested that obstetric and gynecologic procedures may also increase the quantity of visualized perforators via the surgical delay phenomenon.…”

“…76 The latter compounds the risk for kidney injury when also considering the significant impact of obesity in the development of renal disease and metabolic syndrome. 69,76,77 Patient access and positioning can also constrain imaging protocol if there exists a mismatch between patient size and the specifications of the CT machine. 76 Additionally, DelMauro and Moon recently observed fewer major deep inferior epigastric artery perforators among patients with higher BMIs.…”

Patient Safety in Microvascular Plastic Surgery

“…In the setting of lower extremity reconstruction with free tissue transfer, obesity has not been demonstrated to affect overall outcomes. 31,32 While the data on obesity is mixed, malnutrition, a common problem in head and neck reconstruction population, has been shown to have significant association with flap failure whether it is related to wound healing or vascular anastomosis problems. [33][34][35] The evaluation of the patient's nutritional status is a critical part of their preoperative evaluation.…”