Exploring optimal examination to detect occult anastomotic leakage after rectal resection in patients with diverting stoma

BACKGROUND: When considering “early stoma closure”, both standardized inclusion/exclusion criteria and standardized methods to assess anastomosis are necessary to reduce the risk of occult anastomotic leakage (AL). However, in the immediate postoperative period, neither have the incidence and risk factors of occult AL in patients with diverting stoma (DS) been clarified nor have methods to assess anastomosis been standardized. The aim of this study was to elucidate the incidence and risk factors of occult AL in patients who had undergone rectal resection with DS and to evaluate the significance of computed tomography (CT) following water-soluble contrast enema (CE) to detect occult anastomotic leakage. METHODS: This was a single institutional prospective observational study of patients who had undergone rectal resection with the selective use of DS between May and October 2019. Fifteen patients had undergone CE and CT to assess for AL on postoperative day (POD) 7, and CT was performed just after CE. Univariate analysis was performed to assess the relationship between preoperative variables and the incidence of occult AL on POD 7. RESULTS: The incidence of occult AL on postoperative day 7 was 6 of 15 (40%). Hand-sewn anastomosis, compared with stapled anastomosis, was a significant risk factor. Five more cases with occult AL that could not be detected with CE could be detected on CT following CE; CE alone had a 33% false-negative radiological result rate. CONCLUSIONS: Hand-sewn anastomosis appeared to be a risk factor for occult AL, and CE alone had a high false-negative radiological result rate. When considering the introduction of early stoma closure, stapled anastomosis and CT following CE could be an appropriate inclusion criterion and preoperative examination, respectively.