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Randomized Controlled Evaluation of a Novel Endoscopic Stapling System in an Animal Model for GERD
*M1708 Randomized Controlled Evaluation of a Novel Endoscopic Stapling System in an Animal Model for GERD Steven A. Edmundowicz, Juan M. Perrone, Lawrence C. Siegel, James R. Gannoe, Thomas A. Meininger Proposed new endoluminal therapies for GERD require validation in an animal model before human studies are undertaken. We evaluated the ability of a novel flexible endoscopic stapling system to improve objective parameters of the GE junction in an animal model for reflux disease. Methods: 10 mongrel dogs were used. After an overnight fast the animals were sedated and upper endoscoped. Lower esophageal sphincter pressure (LESP) was then measured using a standard pull through technique. All animals then had 100 units Botulinum Toxin (BT) injected endoscopically with a sclerotherapy needle into all 4 quadrants at the level of the lower esophageal sphincter (LES). The endoscopy and manometry were repeated in 10 days and all animals that had a greater than 25% reduction in mean LES pressure were randomized to receive treatment with the endoscopic stapling system or no therapy. Those randomized to treatment had the flexible endoscopic stapling system passed into the region of the GE Junction after general anesthesia. A single 25mm transmural staple line was created in the cardia at or just below the squamo-columnar junction. All animals were observed for change in weight or eating habits. Six weeks following treatment the animals were endoscoped and esophageal manometry was repeated. A laparotomy was completed under general anesthesia and the duodenum was closed with a stapler. A G-tube and pressure transducer were placed in the stomach by separate cannulations. Gastric yield pressure and volume were obtained while infusing water at 200ml/minute and endoscopically observing the distal esophagus for water regurgitation. Results: The endoscopic stapling procedures were easily completed. There were no perioperative complications. Treated animals had a transient change in eating habits that returned to normal within 24 hours. Effect on parameters of the GE junction are listed below. Due to the small number of animals, none of the data comparisons reached statistical significance(p<0.05). Conclusions: This novel endoscopic stapling system functioned effectively and increased LESP, gastric yield pressure and volume in this animal model. Further human studies are warranted.
force). Pull force in the opposite direction again at 90d to the cephalad-caudad axis of the animal was 281 without and 691 grams with SLT (146% increase) (p<0.05). Peak pushing force of the endoscope, positioned in the duodenum in a live pig with a 90d turn into duodenum after entering the pylorus) was 470 without and 1094 grams with the shape locking technology (135% increase in force) (p<0.05). SLT allowed the passage of stents, and needles through the wall of the unsupported stomach which could not be accomplished without. Conclusions: The forces exerted at flexible endoscopy, especially push and lateral 90 degree force were substantially reduced compared with laparoscopic instruments. Lateral force was very limited when using flexible biopsy forceps through flexible endoscopes. Using SLT to restrain the flexible endoscope, a four-fold increase in pushing force was measured. This allowed endosurgical maneuvers to be accomplished, which could not be performed by conventional flexible endoscopes alone.
*M1710 Solutions to Some Difficulties in Sewing at Flexible Endoscopy Paul Swain, Annette Fritscher-Ravens, Sandy Mosse, Per-Ola Park, Keiichi Ikeda, Tim Mills
*M1709 Force Transmission at Flexible Endoscopy with Conventional Endoscopes and Shape Locking Endoscope Guide Catheter Paul Swain, Vahid Sadaat, Rodney Brenneman, Richard Ewers Background: A major limitation to the development of flexible endoscopic surgery is the limitation of force, which can be exerted on needles, catheters and endosurgical surgical instruments in a forwards and sideways direction. The flexibility of the endoscopes and the instruments passing through them reduces precision and control when compared with rigid surgical instruments. Aim: To compare the forces exerted by instruments during endosurgical maneuvers through flexible endoscopes and using shape-locking technology (SLT). Methods: We compared forces exerted pushing needles through tissue using 1: flexible endoscopic grasping forceps holding a threaded needle, 2: needles of 21,19,17 Guage, 3: stents of 5, 7, 10, F over a guide wire which were passed through the wall of a porcine stomach. Studies were performed on the bench with postmortem tissue and were then in live experiments. Push, pull and lateral force were measured with a force gauge. Measurements (n=10 each) were made using instruments in postmortem pig stomach passed through a gastroscope (Olympus 140) and the same gastroscope constrained in SLT guide catheter SG1. Results: In live pig studies, maximum pushing force exerted on the wall of the stomach by forceps passed through the accessory channel of an endoscope in a live pig stomach held at an intragastric angle of 90 degrees(d) was 94.9 grams. When the SLT catheter was locked over the endoscope the force was increased to 431 grams (365% increase in
P148
GASTROINTESTINAL ENDOSCOPY
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.
VOLUME 59, NO. 5, 2004
force). Pull force in the opposite direction again at 90d to the cephalad-caudad axis of the animal was 281 without and 691 grams with SLT (146% increase) (p<0.05). Peak pushing force of the endoscope, positioned in the duodenum in a live pig with a 90d turn into duodenum after entering the pylorus) was 470 without and 1094 grams with the shape locking technology (135% increase in force) (p<0.05). SLT allowed the passage of stents, and needles through the wall of the unsupported stomach which could not be accomplished without. Conclusions: The forces exerted at flexible endoscopy, especially push and lateral 90 degree force were substantially reduced compared with laparoscopic instruments. Lateral force was very limited when using flexible biopsy forceps through flexible endoscopes. Using SLT to restrain the flexible endoscope, a four-fold increase in pushing force was measured. This allowed endosurgical maneuvers to be accomplished, which could not be performed by conventional flexible endoscopes alone.
*M1710 Solutions to Some Difficulties in Sewing at Flexible Endoscopy Paul Swain, Annette Fritscher-Ravens, Sandy Mosse, Per-Ola Park, Keiichi Ikeda, Tim Mills
*M1709 Force Transmission at Flexible Endoscopy with Conventional Endoscopes and Shape Locking Endoscope Guide Catheter Paul Swain, Vahid Sadaat, Rodney Brenneman, Richard Ewers Background: A major limitation to the development of flexible endoscopic surgery is the limitation of force, which can be exerted on needles, catheters and endosurgical surgical instruments in a forwards and sideways direction. The flexibility of the endoscopes and the instruments passing through them reduces precision and control when compared with rigid surgical instruments. Aim: To compare the forces exerted by instruments during endosurgical maneuvers through flexible endoscopes and using shape-locking technology (SLT). Methods: We compared forces exerted pushing needles through tissue using 1: flexible endoscopic grasping forceps holding a threaded needle, 2: needles of 21,19,17 Guage, 3: stents of 5, 7, 10, F over a guide wire which were passed through the wall of a porcine stomach. Studies were performed on the bench with postmortem tissue and were then in live experiments. Push, pull and lateral force were measured with a force gauge. Measurements (n=10 each) were made using instruments in postmortem pig stomach passed through a gastroscope (Olympus 140) and the same gastroscope constrained in SLT guide catheter SG1. Results: In live pig studies, maximum pushing force exerted on the wall of the stomach by forceps passed through the accessory channel of an endoscope in a live pig stomach held at an intragastric angle of 90 degrees(d) was 94.9 grams. When the SLT catheter was locked over the endoscope the force was increased to 431 grams (365% increase in
P148
GASTROINTESTINAL ENDOSCOPY
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.
VOLUME 59, NO. 5, 2004