Novel over-the-scope-clip system for gastrotomy closure in natural orifice transluminal endoscopic surgery (NOTES): an ex vivo comparison study

Background and study aims: Secure transluminal closure remains a fundamental barrier to clinical introduction of natural orifice transluminal endoscopic surgery (NOTES). Current NOTES closure modalities either do not provide secure closure or are too challenging to apply in vivo. The aims of this study were to evaluate gastric closure using the over-the-scope clip (OTSC) system in a previously described experimental setup, comparing the acute strength with a gold standard (hand surgical suturing). Methods: Comparison was done using an ex vivo porcine stomach experimental setup. The gastric opening was created by a needle knife puncture followed by dilation with 18-mm balloon. Control gastrotomies (n = 15; surgical suturing) showed a mean leak pressure of 206 mmHg (SD 59). A non-inferiority design required a sample size of 11 specimens for the OTSC group. Closure comprised: (i) approximation of muscular layers using a flexible twin grasper; (ii) pulling the tissue into the OTSC cap at the tip of the scope; (iii) releasing the clip. Main outcome measures were leak pressure of closed gastrotomies, leak location, and time needed for adequate closure. Results: Closure was successful in all specimens in a median of 3 minutes. Closed gastrotomies showed air leakage at mean pressure of 233 mmHg (SD 47), which was non-inferior compared with the predetermined gold standard (P = 0.003). Conclusions: Closure of gastric incisions to meet a predetermined leak pressure criterion was attainable and easy with the OTSC system. In vivo survival animal experiments are needed to further evaluate this promising closure modality