Randomized Testing Optimizing Parameters for Flexible Endoscopic Suturing in the Stomach Using T-Tag Suture Fasteners

Abstract

Background: Sutured closure of defects, perforations, and NOTES incisions has been accomplished at flexible endoscopy using T-tagged sutures. Influence of suture depth, angle of tissue approach, method of needle puncture, pre-injection with saline cushion need further study to reduce risk of inadvertent adjacent organ puncture and increase efficacy of this type of suturing. Aim: To study parameters influencing placement of T-tag sutures through stomach: Methods: 4 pigs: 30-34 kg, intralumenal insufflation pressure 12 mm, double channel scope, open abdomen, TAS (Ethicon Endosurgery): 20G needle, 8 mm tag central thread 3.0 Pronova. Parameters randomized in groups of 10: length, 0.5, 1.0, 1.5 mm, angles 90, 45, 15, saline cushion, incision in stomach, overlying adjacent tissue, jabbing, controlled needle advancement. Pull-out and push through forces on bench, stomach thickness. Results: Stomach wall-thickness was 3-4.5 mm. 120 needle punctures were evaluated. At 90 degree angle, exposed needle length of 1.5 cm penetrated gastric serosa (10/10). 1 cm also penetrated through serosal surface in 10/10 and 0.5 cm length in 6/10 (but always reached deep muscle). 1.5 cm exited further than needed to deploy transmural tag in all cases vs 1.0 and 0.5 cm lengths (p = 0.002). Comparing 45 with 90 degree exit angles, serosal penetration was reduced to 2/10 at 0.5, 6/10 at 1.0, and 10/10 but still too long at 1.5 mm. With small intestine (SI) laid over stomach, and angle of 90 degrees, 0.5 cm (7/10 cleanly through the serosa, 6/10 touched SI serosa) vs 1 cm penetrated stomach serosa (10/10) but did not penetrate the small intestine but 7/10 touched serosa of SI. Comparing two methods of needle advancement, with needle length set at 1.5 cm, the jabbing method had needle exit stomach cleanly 9/10 times, with one thrust not exiting. One t-tag penetrated small SI and was delivered into the lumen. An alternative method pushed needle gently while the catheter sheath was held against tissue showed 9/10 exiting the stomach well, without penetrating adjacent tissue. Submucosal injection prevented tags placed with 1.0 mm needle length reaching past serosa in 8/10 vs 0/10 without mucosal cushion. Serosally placed tags with submucosal showed reduction in pull-out force by a third. Needle puncture force was low. Needles were reliable, showing no tendency to blunt with 10 uses. Conclusions: Optimal needle length was slightly longer than tissue thickness (0.5-1 cm). Needle penetration of adjacent tissue was eliminated by limiting needle length and using gentle puncture. Preinjection with saline prevented serosal or adjacent organ penetration. T-tag suturing can be performed safely.