The Effect of Preoperative Subcutaneous Fat Thickness on Surgical Site Infection Risk in Patients Undergoing Colorectal Surgery: Results of a Multisite, Prospective Cohort Study.

Surgical site infection (SSI) is one of the most frequent postoperative complications among patients undergoing elective colorectal surgery. A multisite, prospective cohort study was conducted to investigate whether the thickness of subcutaneous fat (TSF) influences the occurrence of SSI in patients undergoing colorectal surgery. Participants included patients scheduled to receive colorectal laparotomy for colorectal cancer and who were under the care of a wound ostomy continence nurse at 17 participating general hospitals in Japan. Patients were not eligible to participate if they had undergone emergency surgery, reoperation, or laparoscopic surgery. Demographic, wound, and surgical data and American Society of Anesthesiologists (ASA) scale scores were collected and assessed, along with nutritional status, TSF, body mass index, and risk factors for SSI (ie, length of surgery and wound classification). The incidence of SSI and nutritional conditions was assessed weekly for 30 days after surgery. Of the 155 participants (mean age 68.9 ± 10.8 years, 53 [34.2%] of whom were women), 90 (58.1%) underwent rectal surgery, and the remaining 65 underwent colon surgery. Seventy-two (72, 46.5%) of the 155 patients underwent colostomy surgery; 24 (15.5%) developed a SSI. The mean onset of SSI was 7.3 ± 2.9 days after surgery and commonly observed in the stoma group when the ASA score was 3 or higher (P = 0.02). Patients who developed SSI resumed oral dietary intake later than those without SSI (7.4 days versus 4.6 days, P = 0.02). Multivariate analysis indicated TSF >15 mm (P = 0.01), Alb level <3.5 g/dL at postoperative days 14 (P = 0.03) and 21 (P = 0.02), and total protein level <6.8 g/dL at postoperative day 7 (P = 0.02) were statistically significantly correlated with SSI occurrence. These results suggest preoperative TSF and preoperative and postoperative serum albumin levels are independent risk factors for SSI in patients undergoing colorectal surgery, confirming current recommendations to maximize the preoperative nutritional status of patients in order to prevent major complications. The results also confirm obesity/TSF should be assessed preoperatively to ascertain the risk of SSI in patients undergoing colorectal surgery.