Influence of Surgical Technique, Performance Status, and Peritonitis Exposure on Surgical Site Infection in Acute Complicated Diverticulitis: A Matched Case-Control Study

Background: Acute generalized peritonitis secondary to complicated diverticulitis is a life-threatening condition; the standard treatment is surgery. Despite advances in peri-operative care, this condition is accompanied by a high peri-operative complication rate (22%-25%). No definitive evidence is available to recommend a preferred surgical technique in patients with Hinchey stage III/IV disease. Methods: A matched case-control study enrolling patients from four surgical units at Italian university hospital was planned to assess the most appropriate surgical treatment on the basis of patient performance status and peritonitis exposure, with the aim of minimizing the surgical site infection (SSI). A series of 1,175 patients undergoing surgery for Hinchey III/IV peritonitis in 2003-2013 were analyzed. Cases (n=145) were selected from among those patients who developed an SSI. The case:control ratio was 1:3. Cases and control groups were matched by age, gender, body mass index, and Hinchey grade. We considered three surgical techniques: T-1=Hartman's procedure; T-2=sigmoid resection, anastomosis, and ileostomy; and T-3=sigmoid resection and anastomosis. Six scoring systems were analyzed to assess performance status; subsequently, patients were divided into low, mild, and high risk (LR, MR, HR) according to the system producing the highest area under the curve. We classified peritonitis exposition as P-1=<12 h; P-2=12-24 h; P-3=>24h. Univariable and multivariable analyses were performed. Results: The Apgar scoring system defined the risk groups according to performance status. Lowest SSI risk was expected when applying T-3 in P1 (OR=0.22), P-2 (OR=0.5) for LR and in P-1 (OR=0.63) for MR; T-2 in P2 (OR=0.5) in LR and in P1 (OR=0.61) in MR; T-1 in P-3 (OR=0.56) in LR; in P-2 (OR=0.63) and P-3 (OR=0.54) in MR patients, and in each P subgroup (OR=0.93;0.97;1.01) in HR. Conclusions: Pre-operative assessment based on Apgar scoring system integrated with peritonitis exposure in complicated diverticulitis may offer a ready-to-use tool for reducing SSI-related complications and applying appropriate treatment, reducing the need for disabling ostomy.