COLONOSCOPIC BOWEL WALL INJECTION EX VIVO BOVINE LARGE BOWEL TEACHING PROGRAM
Neil Mitra*3, Hansani N. Angammana3, Yanni Hedjar2, Poppy Addison3, David Wang1,3, Vincent Chia3, Katherine Carsky3, Katherine Portelli3, Gregory A. Wasserman3, Michael Ma3, Richard L. Whelan3
1Long Island Jewish Medical Center, New Hyde Park, NY; 2Brookdale University Hospital and Medical Center, New York, NY; 3Lenox Hill Hospital, New York, NY
Introduction: In the large bowel, endoscopic Bowel Wall Injections (BWI) are utilized for tattooing, snare polypectomy, EMR, ESD, and hemorrhage. Although the deep wall
(muscularis propria and subserosal layer) is the usual target when tattooing a lesion, injection and expansion of the submucosal layer (SM) is the goal for ESD and EMR. The sclerotherapy needle (SC) method, which requires mucosal puncture, is most commonly used. The main alternative is High Pressure Punctureless (HPP) injection that is done most often with a machine pump. Most MD's get no formal training in BWI and basic endoscopic training programs, generally, do not include this important skill. We designed and tested a training program that teaches trainees to make SM injections using the SC and HPP methods in a non-clinical setting.
Methods: Ex vivo bovine large bowel (anus intact) was used; 40 two mm targets were "branded" onto the mucosa via colotomy (subsequently closed) using a heated nail. The colon was loosely attached to a PEG board and the proximal end zip tie closed. Prior to training a video lecture presenting the devices, methods, injection strategies and common difficulties of each method must be viewed. After completing a brief quiz, trainees move to the colon. Each trainee makes SC and HPP injections (20 injections/method); the SM layer was the target. An instructor makes the syringe SN injections and also provided guidance; all sessions were videoed, timed and each injection scored as to the result (SM, deep wall only, mixed (SM and deep), no lift).
Results: A total of 10 residents and fellows each completed 1 session. As regards the SC method, the lifts generated (mean for group) were: pure SM lifts, 50%; mixed 45%; and deep wall only, 5%. As regards the HPP method the lifts generated were: pure SM lifts, 94%; mixed, 6%; deep wall only, 0%. Injection related mucosal lacerations were noted in 95% of HPP lifts (71% greater than 3 mm) and 0% of SC injections. The mean time to find the target, insert/align the needle and complete the injection was 72 seconds for the SC method and 36 seconds for the HPP method.
Conclusions: The HPP method was quicker and associated with more pure submucosal injections vs the SC method, however, lacerations were very often noted with the HPP method (vs none with SC). Trainees quickly learned the SC method and a SM lift was attained in 95% of injections. Preliminary results with this ex vivo bovine model suggests that inexperienced trainees can learn to make submucosal injections using both methods in several hours time. There is no clinical equivalent to this training approach during which trainees make 40 injections with instruction and immediate feed back. A second training session is planned 2 months after the 1st to refine/reinforce these injection techniques. Further study is needed.
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