Solutions to Some Difficulties in Sewing at Flexible Endoscopy

Abstract

Background: Sewing at flexible endoscopy can be too superficial, requires overtubes or large diameter extensions to the endoscope and is cumbersome. It is largely restricted to placing a few stitches at the cardia for reflux treatments. Aim: to develop methods and devices for sewing with multiple stitches and stitch patterns, to sew using smaller diameter instruments, to vary stitch depth. Materials and methods: A new sewing method (NSM) was developed using a flexible sheathed needle with a metal tag and thread, which passes through the accessory channel. All components of this sewing method including knot tying and cutting mechanisms can be passed through a 2.8mm channel of a conventional gastroscope. Initially developed for endoscopic ultrasound (EUS) this method was tested at gastroscopy without EUS and during transgastric surgery (TGS). Bard Endocinch and prototype sewing, cutting and knot-tying devices were studied. A method for submucosal stitching, with prior saline injections was developed. Following full-thickness gastric resection (FTR), methods for defect closure were compared using z closure, interrupted, continuous, mattress, purse-string (Endocinch), interrupted, full thickness and submucosal (NSM). They were studied under a dissecting microscope and in survival and non-survival experiments in pigs. Results: Studies in post-mortem and live tissue showed that it was possible to sew into the submucosa and to the serosal surface both under EUS control but also without EUS. Prior saline injection made submucosal sewing easy and safe. Submucosal stitches were surprisingly secure with tearing forces of 17N but weaker than serosal 25 N (p<0.05). Serosal stitching without EUS seemed safe. EUS allowed stitches to be placed in specific targets (median arcuate ligament, right crus. gallbladder, small intestine) without soiling the peritoneal cavity. If the stomach was incised and a flexible endoscope passed into the peritoneal cavity (TGS) a new world for endoscopic suturing came into view. Following FTR or TGS, Endocinch and NSM could make the defect watertight with a variety of stitch configurations. NSM could pull in omentum to plug the defect. Purse string suturing was possible providing care was taken not to cross threads. Conclusion: New solutions to difficulties in sewing at flexible endoscopy are presented. They include a method of sewing at flexible endoscopy using small diameter components all of which can pass though a 2.8 mm accessory channel. New methods of serosal and submucosal stitching were developed and tested.