Evaluation of a modified circular stapler for use as a viscerotomy formation and closure device in natural orifice surgery

The most challenging of the many hurdles surgeons must overcome to perform natural orifice translumenal endoscopic surgery (NOTES) safely is viscerotomy closure. The perfect device must be easy to deploy, suitable for use on any viscera, and able to create a rapid, reliable, and durable closure. The authors developed a novel device based on an existing circular stapler platform to create and then subsequently close a viscerotomy. The device was tested initially on an ex vivo porcine stomach model, then used on a survival canine model to confirm adequacy of gastric closure and rapidity of deployment. Three study arms, each containing five stomachs, were used. For the experimental arm, a Surgassist (PMI, Langhorne, PA, USA) powered circular stapler (EEA) modified with an auger tip and premounted endoloops was used. This novel device was compared with two gold standard closure techniques: hand-sewn two-layer closure and linear stapled closure. Each stomach then was inflated slowly with dye, and the pressure at which each closure leaked was recorded. For evaluation of the closure's durability and ease of use, five mongrel dogs undergoing transgastric intraabdominal surgery had their gastrotomy formed and closed using the modified Surgassist stapler. Each animal was survived 14 days, then killed, after which a necropsy was performed. In the ex vivo model, the modified PMI EEA consistently achieved burst pressures exceeding 260 mmHg, which was statistically significant compared with either the hand-sewn closure or the linear stapled closure. In the survival group, all the animals survived for the 2-week study period without signs of sepsis. At necropsy, the closures were found to be intact. The prototype transvisceral purse-string device consistently produced a tight, safe, and reliable closure. It can be deployed and cinch-closed rapidly. This study suggests that this new device may be a promising option for use in NOTES.