How do Swiss surgeons perform fluorescence angiography in colorectal surgery?

Abstract

Anastomotic leak (AL) constitutes one of the most feared complications in colorectal surgery and can occur in up to 36.3% of patients [1]. Reducing the incidence of AL has been the objective of intense research and included preventive measures taken during the pre-, peri-, and postoperative steps [2]. Intraoperatively, selection of the optimal site for anastomosis has to take into account perfusion of the bowel segments to be jointed. Altered blood supply to the bowel, due to hypotension, vasoconstriction caused by vasopressor drugs in the context of a shock, embolus in the context of mesenteric ischemia, or alteration of the local anatomic blood supply after division of the mesentery, leads to tissue necrosis and/or impaired healing of the anastomosis. Historical methods to assess bowel perfusion rely on direct observation of the bowel, looking at the color of the bowel wall and its motility, or by checking bleeding from the divided mesentery. As these methods are operator dependent, subject to interpretation and not reliable in the context of patchy diffuse hypoperfusion, modern methods to objectively assess bowel perfusion have been developed and include measurement of tissue perfusion or assessment of macroperfusion. The latest development in the field consists of fluorescence angiography (FA), which combines the injection of a fluorescent dye into the systemic circulation and visualization of tissue perfusion using an enhanced reality technique. FA has gained increasing interest among colorectal surgeons and has been the subject of intense research. Notably, the PILLAR II study showed that FA led to a change in surgical strategy (site of bowel division) in 7.9% of patients [3]. Recent randomized controlled trials (RCTs) showed that FA led to a change in the level of bowel division in 11% of patients with a nonsignificant reduction in the incidence of AL from 9 to 5% [4], or to a change in surgical strategy in 19% of patients associated with a significant reduction in AL from 16.3 to 9.1% [5]. Although recent evidence suggests that FA could constitute a useful tool for patients and colorectal surgeons, its use in the specialty is still quite limited and its application vary among centers and surgeons. To determine the current practice regarding the use of FA to prevent AL, members of the Swiss College of Surgeons were asked to participate in a cross-sectional online survey containing 35 questions (Table S1). Briefly, 68.7% of colorectal Swiss surgeons were using FA on a regular basis (Table S2). When performing a bowel anastomosis, participants mostly assessed bowel perfusion by looking at the macroscopic aspect of the bowel and by checking the perfusion of marginal blood vessels (Figure S1a). However, to make their final decision, Swiss colorectal surgeons mostly rely on an objective methods, such as FA, which was used to define the definitive surgical strategy by 56.7% of them (Figure S1b). Commercial systems used by participants are reported in Figure S2. Although evidence regarding FA mostly belongs to elective surgery, with very few publications showing its utility in the emergency setting, 89.1% of participants reported using FA in both emergency and elective colorectal surgery procedures (Figure S3a). During surgery, FA was mostly performed to check both bowel anastomosis and perfusion of end segments, such as the rectal stump (67.4% of participants), which might leak after stapling in case of poor perfusion. Thirty-two percent of participants, however, restricted the use of FA to verify anastomotic perfusion (Figure S3b). During creation of an anastomosis, 54.4% of participants reported using FA after division of the mesenteric vessels (and before dividing the bowel), 52.2% just before performing the anastomosis and 50% after performing the anastomosis (Figure S3c). Although there is no clear rule stating when to perform * J. Meyer [email protected]