Water-jet Assisted Esophago-gastric Submucosal Dissection: A Feasibility Study and Exploration of Pressure Effect Settings

Thomas P Cundy, Kumuthan Sriskandarajah, Kunal Shetty, Tou Pin Chang, Mikael H Sodergren, James Clark, Guang-zhong Yang, Ara W Darzi

The Hamlyn Centre for Robotic Surgery, Imperial College London

INTRODUCTION: Natural orifice endoluminal techniques of peroral endoscopic myotomy (POEM) and subepithelial tumor resection rely on creation of a submucosal tunnel working space (1,2). Submucosal dissection is currently achieved using time-consuming and technically difficult methods of blunt dissection, electrocautery, carbon dioxide insufflation, and water irrigation. Flexible probe water-jet devices deliver a high-pressure water jet for rapid development and expansion of anatomical planes such as the submucosal space. To explore application of this new focused energy delivery device for peroral endoluminal surgery, the following objectives were investigated 1) to assess the effect of different water-jet pressure settings for submucosal dissection and 2) to evaluate the risk of inadvertent perforation.

METHODS AND PROCEDURES: Water-jet assisted submucosal dissection was performed on eight porcine ex vivo upper gastrointestinal specimens using the ERBEJET™2 console with the HybridKnife multi-function probe. Pressure effect settings were increased in increments of 5 across a range of 20 – 60 (1 effect setting = ~100kpa). The submucosal space was accessed from pre-prepared 10mm mucosal incisions in the posterior esophagus located 10 cm proximal to the gastro-esophageal junction. The water-jet was deployed from a static position for 10 seconds at zero degrees of angulation using methylene blue stained normal saline. Length and width of submucosal elevation, as well as inadvertent perforations were assessed for each effect setting (Figure 1a).

RESULTS: Submucosal elevation was successfully achieved at each pressure effect setting. A linear relationship was observed between pressure effect setting and submucosal tunnel length (Figure 1b). Direction of tunneling was uniformly straight, with no spiraling effect seen. Submucosal elevation width remained relatively constant across the range of water-jet effect settings used. No instances of mucosal or transmural perforations were encountered.

Figure 1. a) Detubularised esophagus with water-jet probe tip in situ demonstrating submucosal elevation length and width at effect setting 20, b) The effect of water-jet pressure effect settings on submucosal elevation.

CONCLUSIONS: This ex-vivo feasibility study provides encouraging results that support a role for water-jet assisted submucosal dissection to facilitate a fundamental and technically challenging aspect of natural orifice peroral endoluminal surgery. The water-jet effect settings explored appear to be safe, however translation to in vivo tissue is needed. Further research is required to define optimum effect settings for efficient plane preserving dissection.

1. Inoue H, Minami Y, Kobayashi Y, Sato Y, Kaga M, Suzuki M, Satodate H, Odaka N Itoh H, Kudo S. Peroral endoscopic myotomy (POEM) for esophageal achalasia. Endoscopy 2010; 42: 265-271
2. Inoue H, Ikeda H, Hosoya T, Onimaru M, Yoshida A, Eleftheriadis N, Maslli R, Kudo S. Submucosal endoscopic tumor resection for subepithelial tumors in the esophagus and cardia. Endoscopy 2012; 44: 225-230

Session: Poster Presentation

Program Number: P579

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