Endolumenal Full-thickness Colon-wall Resection Using an Over-the-scope-clip: Three Techniques Compared in a Porcine Survival Study

ENDOLUMENAL FULL-THICKNESS COLON-WALL RESECTION USING AN OVER-THE-SCOPE-CLIP: THREE TECHNIQUES COMPARED IN A PORCINE SURVIVAL STUDY

Rieder Erwin, Mesteri Ildiko, Bolton J. Emily, Mathews F. Connor, Timmel B. Gregory, Whiteford H. Mark, Swanström L. Lee

Minimally Invasive Surgery Program, Legacy Health, Portland, OR
Medical University of Vienna, Austria

Objective: It is widely recognized that reliable endoscopic full-thickness resection (EFTR) of the GI-tract would be a desirable adjunct to GI-cancer care. We have recently described a new technique for EFTR, which appeared to overcome several existing drawbacks. T-tag anchoring sutures applied at predetermined margins to a hypothesized colon-lesion had enabled accurate tissue retraction into a clip-application-cap. The release of an over-the-scope-clip allowed tissue closure prior to snare-resection of the inverted tissue. The aim of this survival animal study was to compare this EFTR technique, purely endoscopic or together with laparoscopic overview, with a modified technique using solely endoscopic suction for retraction.
Material and Methods: All experiments were performed on female Yorkshire pigs (51-53 kg). In Group-A laparoscopic overview was used to observe the endolumenal colon-wall resection. Using a standard colonoscope (CF-140L, Olympus) up to five T-tag sutures (TAS, Ethicon EndoSurgery) were applied circumferentially to a hypothesized lesion in the colon. An over-the-scope-clip system (OTSC-System 14/6t, Ovesco Endoscopy USA Inc) was then attached to the endoscope and the T-tag sutures were used to gently and accurately retract the intestinal wall into the clip-application hood. To accomplish pre-resection tissue closure the nitinol-clip was fired by an external release mechanism as soon as complete intestinal wall retraction had been verified. The inverted colon-wall was then removed by snare resection. With the sutures still attached the resected specimens (n=2) were then easily withdrawn from the colon. In Group-B the same technique was performed purely endoscopically without laparoscopic overview (n=5). In Group-C solely suction was used instead of T-tag sutures for purely endoscopic tissue retraction (n=6). After the procedures the animals were survived for 14 days followed by necropsy in standard fashion. Resection sites and specimens were histologically analyzed.
Results: EFTR in the colon was achieved in all attempted interventions (13/13). The overall mean interventional time was 33.0±21 min. The full-thickness colon specimens had an overall mean diameter of 23.0 mm ± 5.6 mm.
In Group-A no signs of leakage or infection were found. At the resection sites normal healing without stenosis was observed macroscopically and histologically. Both clips were already passed with the stool. In Group-B the first two EFTR (2/5) also resulted in appropriate healing with the clips already passed. However, the other three resections led to intestinal fistulas (3/5). When solely endoscopic suction was used for tissue retraction no related fistula was found in Group-C, with some clips still in place (4/6). Pure endoscopic suction without T-tags impaired accurate resection and appropriate safety margins were barely possible.
Conclusion: Endolumenal full-thickness resection in the colon, using T-tags for tissue retraction and an over-the-scope-clip for pre-resection closure seems feasible but only if laparoscopic overview is used. At this stage pure endoscopic EFTR cannot be recommended.