Comparing over-the-scope clip versus endoloop and clips (KING closure) for access site closure: a randomized experimental study

A safe technique is essential for successful access site closure in Natural Orifice Translumenal Endoscopic Surgery (NOTES) and for closures of iatrogenic perforations. To compare an over-the-scope clip (OTSC) versus an endoloop + endoclips closure technique (KING closure). 40 minipigs underwent NOTES peritoneoscopy with liver biopsy. Gastrotomies and rectotomies were closed with OTSC (n = 20; 10x stomach, 10x rectum) or KING closure (n = 20; 10x stomach, 10x rectum). The animals were euthanized 28 days after the procedure. The main outcome variables were technical feasibility, effectiveness, and healing. Stomach: All but one closure (KING) was successfully completed. The times of closure were similar between the techniques. At necropsy, all access sites were healed. In two animals (1x KING, 1x OTSC), an abscess, probably related to the closure technique, was found. Histologically, transmural healing with muscular bridging was observable in nine pigs for KING versus two pigs for OTSC closure (p = 0.003). Inflammation was present in three pigs for KING versus seven pigs for OTSC closure (p = 0.08). Rectum: All closures were successfully completed. The times of closure were similar between the techniques. At necropsy, all closure sites had healed. Transmural healing with muscular bridging was present in nine pigs for KING versus two pigs for OTSC closure (p = 0.003). Inflammation was present in two pigs for KING versus seven pigs for OTSC closure (p = 0.03). In one animal (OTSC), an enterocolic fistula developed in the proximity of the closure site. OTSC and KING closure are comparable closure techniques in terms of technical feasibility and effectiveness. KING closure provides a superior histological outcome compared with OTSC closure.