New Applications for Submucosal Tunneling in Third Space Endoscopy: A Comprehensive Review

Novel device for blunt dissection in third space endoscopy: Preliminary animal study (with video)

Background and study aims

Blunt dissection is not commonly performed in flexible endoscopic procedures. We developed a novel blunt dissection device and evaluated its feasibility, safety, and potential effectiveness in third space endoscopy procedures.

Materials and methods

The device consists of a cotton swab and a flexible shaft. To evaluate its functionality, creation of 4-cm submucosal tunnels in live swine stomachs was attempted by either blunt dissection using our device or sharp dissection using a standard monopolar knife. Data on factors such as completion rate, operating time, adverse events, necessity of submucosal injection, and dissected submucosal thickness were collected.

Results

Eighteen submucosal tunnels were successfully created (sharp: 9, blunt: 9) by two experienced endoscopists and one novice endoscopist. Median operating time was significantly shorter in the blunt dissection group (239 vs. 429 s, P = 0.008). In the sharp dissection group, the experienced endoscopists did not cause any muscle layer injuries, but the novice endoscopist caused muscle layer injuries in all cases. In the blunt dissection group, neither experienced nor novice endoscopists caused muscle layer injuries. The blunt dissection group required significantly fewer submucosal injections (0 vs. 5, P < 0.001). Median dissected submucosal thickness was similar between the groups.

Conclusions

Blunt dissection using our device was feasible, safe, and potentially effective in third space endoscopy procedures by shortening operating time, reducing submucosal injections, and potentially minimizing muscle layer injury.

Electrosurgical knife with the water‐jet function of tip‐type during endoscopic treatment injection

Objectives

This study aimed to objectively evaluate the water‐jet‐functioned electrosurgical knife injection performances in a desktop experiment.

Methods

Five types of water‐jet‐functioned electrosurgical knives, including two injection styles of sheath‐type (A: DualKnife J, KD‐655L; B: FlushKnife, DK2620‐J‐B20S; C: Splash M‐Knife, DN‐D2718B; D: ISSEN, SN1650‐20) and tip‐type (E: ORISE ProKnife, M00519361) were evaluated. These knives were compared with an injection needle (Control: SuperGrip 25G) as a control. The injection speed under constant pressure and the injection efficiency for each knife against prepared porcine stomach mucosa were evaluated. The additional clear gel injections using an injection needle were observed using an indigo blue‐colored gel to evaluate the difference between the locations of water‐jet holes.

Results

Four types of knives, except for A, showed significantly higher water‐jet speeds (A: 0.79 ± 0.03 g/20 s, B: 2.56 ± 0.05 g/20 s, C: 3.09 ± 0.06 g/20 s, D: 2.86 ± 0.05 g/20 s, and E: 1.79 ± 0.03 g/20 s) compared to that of the control (1.21 ± 0.03 g/20 s). Meanwhile, significantly higher efficacy of injection was found in the tip‐type water‐jet function knife, second to the injection needle (Control: 37.2% ± 35.5%, A: 20.9% ± 20.2%, B: 1.1% ± 2.2%, C: 6.2% ± 12.6%, D: 12.5% ± 15.6%, and E: 33.3% ± 32.2%). An additional injection experiment revealed that the injection with a piercing tip into the gel could achieve sufficient additional injection inside the stacked clear gel.

Conclusions

The tip‐type water‐jet function electrosurgical knife is preferable for effective submucosal injection during endoscopic treatments.