A COLONOSCOPIC OVERTUBE SYSTEM THAT CREATES A "THERAPEUTIC ZONEā? AND PERMITS RETRACTION FACILITATES ESD AND WAS ASSOCIATED WITH SHORTER CASES, FEWER INSTRUMENT EXCHANGES, AND USE OF LESS LIFTING SOLUTION VS CLASSIC ESD IN AN EX VIVO BOVINE MODEL.
Xiaohong Yan1, Neil Mitra*1, Dasuni Niyagama Gamage2, Vesna Cekic1, HMC Shantha Kumara1, Abhinit Shah1, Richard L. Whelan1
1Lenox Hill Hospital - Northwell, New York, NY; 2Vassar Brother's Medical Center, 25 Reade Place Poughkeepsie, NY
Introduction: Endoscopic Submucosal Dissection (ESD) permits en bloc resection of sessile colorectal polyps. Classic ESD (C-ESD) is difficult and not widely used because: 1) precise control of the moving scope tip with knife extended is needed to cut tissue and 2) the only ways to retract the target tissue is gravity and the dissection cap on the scope tip. An overtube device (ORISE Tissue Retraction System [TRS]) is now available for distal lesions that has an expandable cage that creates a "therapeutic zone". The device overtube has 2 instrumentation channels (ICās) through which a grasper(s), separate from the scope, is placed to retract the cut edge. To assess the TRS device a "randomized" study comparing C-ESD to TRS ESD was carried out with an ex vivo bovine colon model.
Methods: Bovine colons (with rectum and anal sphincter), obtained as per USDA regulations and agreement, were mechanically cleaned, filled with antibiotics x 12 hours, then frozen (-80 Ā°C) until used. One C-ESD and 1 TRS were done per colon; the order of dissection was alternated for each colon (proximal/distal). Two "polyps" are created via a brand (2 cm diameter) made with a heated round wire via a colotomy that is suture closed (30 cm and 20 cm from anus). The colon is affixed to a peg board and the proximal end clamped. A pediatric scope was used for all cases. Mucosal lifts are made with a sclerotherapy catheter and saline. Standard methods were used for C-ESD cases. In TRS cases the lift is made and the full target disc circumference incised with the colonoscope (C) alone prior to insertion of scope and overtube. The cage is positioned over the lesion and a grasper passed through the IC is used to grasp the distal edge of the target disc. The cage is opened to elevate the cut edge. A needle knife is then used to detach the lesion. To learn the TRS method, 12 training ESDs were done prior to the study. Study ESDās were recorded and key parameters noted and results compared.
Results: 25 classic and 25 TRS ESD cases were done (25 colons). En bloc resections (plus clear margins) were made for all lesions. TRS case time (median 35, range 24-84 minutes) was 7 minutes less than C-ESD result (median 42, range 27-99 minutes, p<0.05). Less lift solution was used in TRS cases (Median=39, range 23-64ml) vs C-ESD (Median=55, range 28-97.5ml, p<0.01), fewer instrument exchanges made (TRS, median=5, range 3-12; vs C-ESD, median=9, range 4-17, p<0.01), and fewer deep muscle injuries were noted in TRS cases (Median=2, range 0-5; vs C-ESD, Median=3, range 0-9, p=0.056).
Conclusions: Once the TRS skillset is obtained, TRS facilitated more rapid completion of rectal and distal sigmoid ESD and required fewer instrument exchanges and less lift solution than C-ESD. The ability to retract the cut edge is the main benefit. Further study is needed.
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