The management of complicated diverticulitis and the role of computed tomography

Purpose: Acute diverticulitis is a disease with a wide clinical spectrum, ranging from a phlegmon (stage Ia), to localized abscesses (stages Ib and II), to free perforation with purulent (stage III) or feculent peritonitis (stage IV). While there is little debate about the best treatment for mild episodes and/or very severe episodes, uncertainty persists about the optimal management for intermediate stages (Ib and II). The aim of our study was therefore to define the role of computed tomography (CT) and to analyze its impact on the management of acute diverticulitis. Methods: We retrospectively analyzed 511 patients (296 males, 215 females) admitted for acute diverticulitis between January 1994 and December 2003. Excluded were patients with stoma reversal only, "diverticulitis" mimicked by cancer, or significantly deficient patient records. Patients were analyzed either as a whole or subgrouped according to age (<40 yr, >40 yr). A modified Hinchey classification was used to stage the severity of acute diverticulitis. Results: In 99 patients (19.4%), an abscess was found (74 pericolic, 25 pelvic, median diameter: 4.0 cm). CT-guided drainage was performed in 16 patients, one failure requiring a two-stage operation. Whereas conservative treatment failed in 6.8% in patients without abscess or perforation, 22.2% of patients with an abscess required an urgent resection (68.2%, one-stage, 31.8%, two-stage). Recurrence rates were 13% for mild cases, as compared to 41.2% in patients with a pelvic abscess (stage II) treated conservatively with/without CT-guided drainage. Of all surgical cases, resection/primary anastomosis was achieved in 73.6% with perioperative mortality of 1.1% and leak rate was 2.1%. Conclusions: CT evidence of a diverticular abscess has a prognostic impact as it correlates with a high risk of failure from nonoperative management regardless of the patient's age. After treatment of diverticulitis with CT evidence of an abscess, physicians should strongly consider elective surgery in order to prevent recurrent diverticulitis.