Does obesity increase the risk of incisional hernias after surgery for colorectal cancer?

This study investigated the relationship between two different obesity measurements and the risk of incisional hernia (when the intestines push through the surgical scar or the surrounding tissue).

Incisional hernias are one of the most common surgical complications after surgery for colorectal cancer. Between 4% and 21% of patients who undergo surgery suffer from an incisional hernia. More than 33% of these patients will be in pain or discomfort as a result of the hernia. A number of factors can increase the risk of incisional hernias including the surgical technique, poor wound healing and obesity.

One of the most common ways to measure obesity is using body mass index (BMI) calculations. BMI is calculated based on a person’s height and weight, but it does not account for the type of fat or where it is located in the body. Specifically measuring visceral fat (the fat located around the internal organs) might be a better predictor for incisional hernia.

This study analyzed medical records from 193 patients who underwent surgery for colorectal cancer. Patient BMI was calculated and their visceral obesity was measured using a body scan (computerized tomography scan, a type of x-ray). The rate of incisional hernias was recorded after surgery. The rates of infection at the incision site were also measured.

Forty-one patients (21.2%) developed an incisional hernia. On average it took 2.07 years for the hernia to develop. 26.8% of the hernias were symptomatic.

When BMI calculations were used to classify patients as obese or non-obese, obese patients had higher rates of infections at the site of surgery compared to non-obese patients. Overall, 22.7% of the obese patients suffered from an infection compared to only 9.4% of non-obese patients. There was no significant difference in the rate of incisional hernias between obese and non-obese patients classified using BMI.

When visceral fat volume was used to classify patients as obese or non-obese, obese patients had higher rates of infections at the site of surgery and incisional hernias than non-obese patients. Overall, 25.8% of obese patients had infections at the site of surgery compared to 7.9% of non-obese patients. 31.8% of obese patients had an incisional hernia compared to 15.7% of non-obese patients.

The authors concluded that visceral fat volume can help predict patients who are at higher risk of developing incisional hernia. They also highlight that BMI was not a major risk factor for the development of incisional hernias.