Dye-enhanced selective laser ablation for surgical mucosectomy

The diode laser operates at a wavelength of 805 nm; indocyanine green (ICG) has a maximum energy absorption of a wavelength of approximately 800 nm. The effect of the diode laser as a laser knife can be significantly enhanced with an injection of ICG. In the present study, this dye-enhanced photothermal effect was investigated in the field of surgical endoscopy. A 9-cm2 region of the canine gastric mucosa was removed by the laser after injection of 5 ml of ICG solution at a concentration of 0.5 mg/mL into the submucosal space. The diode laser was used at a power output of 10 watts. The canine stomach was removed 10 days after the operation to investigate the site histologically. Clinical application using transanal endoscopic microsurgery (TEM) was employed using a dye-enhanced laser in five patients with a rectal adenoma. The pathological changes in the canine gastric wall resected 10 days after the operation showed that the low-power laser enhanced by ICG produced less fibrosis in the submucosal space than electrocautery. Mucosal resection using a dye-enhanced laser was easily performed in these five patients. It was concluded that this easy removal of the mucosa by a dye-enhanced laser was due to its ability to produce hemostasis of the vessels and its excellent tissue-cutting effect.