Ex vivo experimental study on the Thulium laser system: new horizons for interventional endoscopy (with videos).

Background and study aims The Thulium laser system (TLS) is an emerging interventional tool adopted in many surgical specialties. Its 2.0-mu m wavelength allows precise coagulation (0.2-0.4mm in depth) and cutting, limiting the possibilities of collateral injuries. We tested the impact of the TLS for gastric endoscopic submucosal dissection (ESD) and per oral endoscopic myotomy (POEM) ex vivo in pigs. Materials and methods Ex vivo porcine stomach and esophagus models underwent 2 POEMs, and 3 ESDs (mean diameter 3.5 cm) with TLS using a 272-mu m and a 365-mu m thick optical fibers. Both continuous and pulsed laser emission were evaluated. Subsequent histopathological analysis was performed by an expert GI pathologist on the whole porcine models. Results Complete POEMs and gastric ESDs were successfully performed in all cases in 30 to 70 and 15 to 20 minutes. Both optical fibers were equally effective and precise. The best power output for mucosal incision was 25 to 30W during ESD and 25W for POEM using continuous laser emission. During submucosal dissection and tunneling the favorite power output was 20W and 15 to 20W, respectively, operating in continuous mode. No transmural perforation occurred throughout the operations and histopathology confirmed the absence of accidental muscular layer damage. Conclusions The TLS stands out as a precise and manageable instrument in ex vivo models. This technique appears to be a promising tool for advanced interventional endoscopy.