Experimental Evaluation of the Mechanical Strength of the Stapling Techniques: Experimental Study on Animal Model

The creation of a gastrointestinal tract anastomosis is a fundamental and important surgical procedure. The mean incidence of clinically apparent leakage after gastrointestinal tract anastomosis ranges from 2.1% to 14.9%. Although many techniques for successfully producing such anastomoses have been described, the goal of these techniques to be technically feasible and safe. In the 1960s, Steichen and Ravitch introduced stapling instruments. During the subsequent years, automatic stapling instruments have continued to be refined, and many automatic anastomotic techniques have been applied to gastrointestinal surgery. In addition, various instruments and techniques for stapling intestinal anastomoses have been applied to colorectal surgery. Functional end-to-end anastomosis (FETEA), stapled end-to-end anastomosis (ETEA), and stapled side-to-end anastomosis (STEA) are the most common techniques. Moreover, there are two types of stapled ETEA, the single stapling technique (SST) and the double stapling technique (DST). Although these methods have been shown to be reliable and safe, anastomosis leakage remains a major problem. Major leakages affect the long-term quality of life (QOL) of patients. In addition, leakage can cause significant morbidity. Studies have reported that the frequency of leakage ranges from 2.9 to 23%, and that the shorter the distance from the anal verge to the anastomosis the greater the risk of leakage. As mentioned above, automatic stapling instruments have been refined over the years, and many automatic anastomotic techniques have been applied to colorectal surgery; however, the optimal instrument and method remain unclear. Since the mechanical strength of an anastomosis is an important factor affecting leakage during the initial postoperative phase, experimental evaluation of this factor would be useful for clarifying these issues. In this chapter, we examined the pressure required to induce failure (bursting pressure) in various kinds of stapled anastomosis and investigated which stapling technique is most suitable.