A Systematic Review of Assessment Methods and Impact of Mechanical Tension on Bowel Anastomoses

BackgroundWhile tension on anastomoses is primarily regarded as a critical factor in anastomotic leaks and failure, assessing this tension is based on subjective surgeon estimation. There is currently no clinically available tool to assess mechanical tension on an anastomosis objectively. Some animal and human studies have previously evaluated anastomotic tension, but no comprehensive review discusses the different methods and types of tension measured. ObjectivesTo summarize the current state of the literature regarding the measurement and impact of tension on bowel anastomoses. DesignThis scoping review was conducted with a systematic search of literature in the PubMed, SCOPUS, and EMBASE databases. Key terms used were anastomoses/anastomosis, tension, bowel, surgery, intestine, tissue, small bowel, large bowel, bowel, mucosal tissue, and other corollary terms. Data were synthesized in tables, and summarized paragraphically, with studies assessed using the New-Castle Ottawa scale where possible. Emphasis was placed on method of tension assessment, outcomes, and factors relating to tension. ResultsAnastomotic leak and tension are strongly associated, with the presence of tension making leaks up to 10 times more likely. While freedom from tension has traditionally been measured via the surrogate measure of adequate bowel mobilization, this remains a subjective and imprecise method. The literature describes several techniques to allow adequate mobilization, such as splenic flexure mobilization or division of the omentum. However, basing the estimate of tension on subjective assessment has some inherent drawbacks. Animal and cadaveric studies have been the frontier for objective measurement of wall tension, with the use of scaffolds, suture types, and prostheses to bolster the natural tolerance of the bowel. However, these tend to use tensiometers to measure tension, along with automated machines or pulley and ratcheting systems to increase tension in specified intervals. These are universally destructive due to their design of measuring maximal tensile load as well as not being easily adaptable to the operating room. ConclusionsThe current literature does not study objective measurement of bowel tension in live human subjects. Bowel mobilization is a common method to reduce tension, but it relies on subjective judgment, which varies between surgeons. Given the recognized importance of tension, developing an objective, safe, intra-operative method to measure bowel wall tension would be a valuable surgical tool.