Clinical relevance of the 3-cm threshold in sigmoid diverticulitis with abscess: consensus or quandary?

Diverticular abscess is a common manifestation of acute complicated diverticulitis. We aimed to analyze the clinical course of patients with diverticular abscess initially treated conservatively.

All patients with diverticular abscess undergoing elective or urgent/emergency surgery from October 2004 to October 2022 were identified from our institutional database. Depending on the abscess size, patients were divided into group A (≤ 3 cm) and group B (> 3 cm). Conservative treatment failure was defined as clinical deterioration, persistent or recurrent abscess, or urgent/emergency surgery. Baseline characteristics and short-term perioperative outcomes were recorded and compared between both groups. Uni- and multivariate analyses were conducted to identify determinants of conservative treatment failure and overall ostomy formation.

A total of 105 patients were enrolled into group A (n = 73) and group B (n = 32). Uni- and multivariate analyses revealed abscess size as the only significant factor of conservative therapy failure [OR 9.904; p < 0.0001], while overall ostomy formation was significantly affected by an increased body mass index (BMI) [OR 1.366; p = 0.026]. There were no significant differences in perioperative outcome with the exception of a longer total hospital stay in patients managed with abscess drainage compared to antibiotics alone prior surgery in group B (p = 0.045).

Abscess diameter > 3 cm is not just an arbitrary chosen cut-off value for drainage placement but has a prognostic impact on medical treatment failure in patients with complicated acute diverticulitis. In this subgroup, the choice between primary drainage and antibiotics does not appear to influence outcome at the cost of prolonged hospital stay after drainage insertion.