Endoscopic mucosal incision by diode laser for early cancer treatment in the alimentary tract: effect of submucosal indocyanine green solution injection

Abstract

Mucosal incision technique by diode laser ablation was studied to ensure the operation of endoscopic mucosal resection (EMR), which is gold standard method for early gastric cancer with little/no risk of lymphnode metastasis. Our method was designed to facilitate grasping a large lesion by hitching the snaring wire on the incised mucosal groove around the lesion. We employed local submucosal injection of indocyanine green (ICG) solution. ICG solution was used to prevent direct laser light penetration to the muscularis propriae owing to strong absorption of 805nm light (absorption coefficent at 805 nm is about 200cm-1). We used diode laser radiation with an output of 25W by contact (0.1, 0.5, 1.0 kg/cm2) and non-contact irradiation methods. In the preliminary experiment with resected porcine stomach, muscularis propriae was intact by the 60s non-contact irradiation or the 8s contact irradiation with contact pressure of 1kg/cm2. In the endoscopic experiment we used 3 dogs. Using conical contact probe, we successfully demonstrated 3cm diameter circular incision with sharp groove in 10 minutes. We could place the snaring wire on the incised groove. Histology of the endoscopically incised canine stomach revealed that the submucosal layer welled up to 6mm in thickness and the bottom of the incision groove reached 1.9mm at deepest below the mucosal muscle. The thickness of the coagulation layer around the incised groove was up to 1.8mm. No damage was seen a the muscularis propriae. We demonstrate easy as well as sure snaring by using our laser incision technique. We think our technique may be available to enhance the efficacy of EMR for early gastric cancer including the lesion over 2cm in diameter.© (1999) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.