Visceral obesity, not elevated BMI, is strongly associated with incisional hernia after colorectal surgery.

BACKGROUND High BMI is often used as a proxy for obesity and has been considered a risk factor for the development of an incisional hernia after abdominal surgery. However, BMI does not accurately reflect fat distribution. OBJECTIVE The purpose of this work was to investigate the relationship among different obesity measurements and the risk of incisional hernia. DESIGN This was a retrospective cohort study. SETTINGS The study included a single academic institution in New York from 2003 to 2010. PATIENTS The study consists of 193 patients who underwent colorectal cancer resection. MAIN OUTCOME MEASURES Preoperative CT scans were used to measure visceral fat volume, subcutaneous fat volume, total fat volume, and waist circumference. A diagnosis of incisional hernia was made either through physical examination in medical chart documentation or CT scan. RESULTS Forty-one patients (21.2%) developed an incisional hernia. The median time to hernia was 12.4 months. After adjusting for patient and surgical characteristics using Cox regression analysis, visceral obesity (HR 2.04, 95% CI 1.07-3.91) and history of an inguinal hernia (HR 2.40, 95% CI 1.09-5.25) were significant risk factors for incisional hernia. Laparoscopic resection using a transverse extraction site led to a >75% reduction in the risk of incisional hernia (HR 0.23, 95% CI 0.07-0.76). BMI > 30 kg/m was not significantly associated with incisional hernia development. LIMITATIONS Limitations include the retrospective design without standardized follow-up to detect hernias and the small sample size attributed to inadequate or unavailable CT scans. CONCLUSIONS Visceral obesity, history of inguinal hernia, and location of specimen extraction site are significantly associated with the development of an incisional hernia, whereas BMI is poorly associated with hernia development. These findings suggest that a lateral transverse location is the incision site of choice and that new strategies, such as prophylactic mesh placement, should be considered in viscerally obese patients.