Treatment of patients with acute colonic diverticulitis complicated by abscess formation: A systematic review.

PURPOSE: This study aimed to systematically review the literature and present the evidence on outcomes after treatment for acute diverticulitis with abscess formation. Secondly, the paper aimed to compare different treatment options. METHODS: PubMed, EMBASE and the Cochrane Library were searched. Two authors screened the records independently, initially on title and abstract and subsequently on full-text basis. Articles describing patients treated acutely for Hinchey Ib and II were included. Results were presented by treatment, classified as non-operative (percutaneous abscess drainage (PAD), antibiotics, or unspecified non-operative strategy), PAD, antibiotics, or acute surgery. The outcomes of interest were treatment failure, short-term mortality, and recurrence. RESULTS: Of 1723 articles, 42 studies were included, describing 8766 patients with Hinchey Ib-II diverticulitis. Observational studies were the only available evidence. Treatment generally failed for 20% of patients, regardless of non-operative treatment choice. Abscesses with diameters less than 3 cm were sufficiently treated with antibiotics alone, possibly as outpatient treatment. Of patients treated non-operatively, 25% experienced a recurrent episode during long-term follow-up. When comparing PAD to antibiotic treatment, it appeared that PAD lead to recurrence less often (15.9% vs. 22.2%). Patients undergoing acute surgery had increased risk of death (12.1% vs. 1.1%) compared to patients treated non-operatively. Of patients undergoing PAD, 2.5% experienced procedure-related complications and 15.5% needed adjustment or replacement of the drain. CONCLUSIONS: Observational studies with unmatched patients were the best available evidence which limited comparability and resulted in risk of selection bias and confounding by indication. Diverticular abscesses with diameters less than 3 cm might be sufficiently treated with antibiotics, while the best treatment for larger abscesses remains uncertain. Acute surgery should be reserved for critically ill patients failing non-operative treatment. Further research is needed to determine the best treatment for different sizes and types of diverticular abscesses, preferably randomized controlled trials.