High-power 450 nm blue diode laser for endoscopic mucosal resection/endoscopic submucosal dissection in the stomach: Preliminary results on a porcine model with a modified flexible endoscope.

Background: Due to the precise vaporization of the novel 450 nm blue diode laser in soft tissues (i.e., bladder and colon) in our previous studies, porcine stomach tissues were applied here to certify its efficacy in endoscopic mucosal resection (ESR)/endoscopic submucosal dissection (ESD) for hypothetical lesions ex vivo and in vivo.

Materials And Methods: In an ex vivo study of ESR, 20 pieces of tissues (8 cm × 6 cm) from 7 fresh stomachs after spraying saline were vaporized with a three-dimensional scanning system using the blue diode laser at a maximum of 30 W, a different treatment speed and working distance (WD). In ex vivo ESD, 18 pieces of tissues from 6 fresh stomachs were used and the same laser parameters were used to perform the procedure. The depth, width, and coagulation of the laser vaporization were measured. Furthermore, the large scales (2.0 cm × 1.5 cm) for 18 hypothetical lesions of the gastric mucosa and submucosa of the 6 fresh stomachs were also resected with a modified flexible endoscope. In vivo, six hypothetical lesions of six porcine were vaporized by the novel blue laser, and the resultant lesions at the acute and chronic stages were assessed by the naked eye and hematoxylin and eosin staining.

Results: In the contact mode, more tissue was vaporized, and the thickness of the coagulation was stable when the WD was 0-2 mm, whose value varied from 0.33 to 1.73 mm. In the gastroscopy model, the mean thickness of coagulation from the mucosa was 0.67 mm, and a significant carbonization zone was not observed. In vivo, the laser beam could accurately act on the hypothetical target. No bleeding and clear vision were present in the procedure. After 3 weeks, tissue healing was well recovered after laser coagulation, resection, and submucosal dissection.

Conclusions: In the present study, the novel 450 nm blue diode laser exhibited ideal vaporization and thinner coagulation thickness in the porcine stomach, which indicated that it could be alternately used as a new device for stomach lesions.