The role of Kono-S anastomosis and mesenteric resection in reducing recurrence after surgery for Crohn's disease. A systematic review.

OBJECTIVES: Recurrence after surgery for Crohn's disease is common. Anastomotic configuration may influence recurrence and the mesentery may be key. Recently the Kono-S anastomosis and radical mesenteric excision have been proposed as methods of reducing recurrence. We analysed the literature pertaining to these novel techniques METHODS: We searched MEDLINE, EMBASE and the Cochrane Library for, and selected, studies evaluating Kono-S anastomosis and/or radical mesenteric excision in Crohn's disease. We assessed methodological quality and risk of bias using the Cochrane risk of bias tool for randomized controlled trials and the Joanna Briggs Institute tool for non randomized trials. Narrative synthesis was used to summarise the findings. RESULTS: Nine studies (896 patients) were identified. Apart from one RCT with a low risk of bias the overall level of evidence was poor (Grade IV). The Kono-S anastomosis was associated with a lower incidence of endoscopic and surgical recurrence (0-3.4% vs 15-24.4% respectively). Complications, particularly anastomotic leak rate were also lower (1.8% vs 9.3% respectively). Evidence from a single poor quality study suggested that mesenteric excision may reduce surgical recurrence rates when compared mesentery preservation. DISCUSSION: Existing literature suggests the Kono-S anastomosis is safe and may reduce endoscopic and surgical recurrence, but level of evidence is mainly poor. One element of the Kono-S technique, preservation of the mesentery, may be detrimental to recurrence. Further, higher quality, studies are required to investigate these techniques. Such studies should consider the impact of the degree of mesenteric resection in addition to the anastomosis on disease recurrence.