Novel OTSC system for NOTES gastrotomy closure: An ex vivo comparison study

R.P. Voermans1,2 MD, M.I. van Berge Henegouwen2 MD, PhD, C-N. Ho3, W.A. Bemelman2 MD, PhD, P. Fockens1
1 Dept. of Gastroenterology and Hepatology, 2Dept. of Surgery , Academic Medical Center, Amsterdam, the Netherlands
3OVESCO Endoscopy AG, Tuebingen, Germany

Introduction: Secure translumenal closure remains one of the fundamental barriers to the clinical introduction of NOTES. Current NOTES closure modalities do either not result in secure closure or are too challenging to apply in vivo. Gastrotomy closure using a novel over-the-scope clip (OTSC)(Ovesco) may result in secure closure and may be easy too apply. Aim was to assess the technical feasibility of gastrotomy closure using the OTSC and to compare burst strength with the surgical suture in a previously described ex vivo porcine stomach model(1).
Methods: Stomachs were harvested from freshly slaughtered adult pigs. Standardized gastrotomies were made by dilating a full thickness stab incision with an 18mm balloon for 60 seconds. After closure security was evaluated using a custom apparatus consisting of a pressurized lower chamber and saline filled upper chamber, which were separated by the sutured test specimens. After fixing the test specimen in the apparatus air was infused into the lower chamber until air bubbles could be seen coming through the gastrotomy or the adjacent gastric tissue tore. A pressure gauge and two cameras recorded the leak pressure and mode of failure respectively, with data being captured in real time by computer. Fifteen control gastrotomies were closed with #3-0 PDS in simple interrupted. This resulted in a mean leak pressure of 206 mmHg (SD 59).(1) Using a non-inferiority design a sample size of 11 specimens needed to be included in the experimental group. Closure procedure consisted of 3 steps: (1) Approximation of serosal layers using a flexible twin grasper (2) Pulling the tissue into the OTSC cap at the tip of the scope and (3) Releasing the clip.
Results: Closure was successful in all specimens in a median of 3 minutes. Closed gastrotomies using the OTSC showed air leakage at a mean pressure of 224 mmHg (SD 61), which was non inferior in comparison with the predetermined gold standard (p=0.003).
Conclusion: Use of OTSC for gastrotomy closure is feasible, easy to apply and provides burst pressures comparable with hand-sewn closure. In vivo survival experiments will need to be performed to further evaluate the technique in real life.

(1) Voermans RP, Worm AM, van Berge Henegouwen MI et al. In vitro comparison and evaluation of seven gastric closure modalities for natural orifice transluminal endoscopic surgery (NOTES). Endoscopy 2008; 40: 595-601.

Session: Poster

Program Number: P290

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