Dual-wavelength (980/1470 nm) laser incisions in porcine colon tissue: a histological in vitro study

This study examines the effects of a new dual-wavelength laser (980-nm and 1470-nm) on intestinal tissue incisions. The 980-nm laser efficiently absorbs hemoglobin and water, while the 1470-nm laser excels in water absorption. Therefore, these wavelengths offer significant advantages for tissue cutting and coagulation. Although dual-wavelength lasers are used in urology and gynecology, their application in colorectal surgery remains undocumented. Fresh porcine colon tissue was secured to a custom-designed X-axis mobile platform equipped with computer-controlled electric stepper motors. A dual-wavelength laser system, mounted on this platform, traversed linearly at a velocity of 2 mm/s, maintaining the working tip at a 90° angle relative to the tissue surface. A total of thirty-five tissue specimens were collected for each experimental group (980-nm laser, 1470-nm laser, and a combination of 980/1470-nm lasers in a 1: 1 power mode) and subsequently compared to specimens treated with a high-frequency electric knife. Histological analysis was conducted following Hematoxylin and Eosin (H&E) staining. The application of ANOVA for data following a normal distribution or the utilization of non-parametric tests for data that do not conform to a normal distribution. Complete penetration of the colon is characterized by the longitudinal section penetration of the mucosal, submucosal, muscular, and serous layers of intestinal tissue, as observed in hematoxylin and eosin (HE) stained sections. This level of penetration was achieved at 72 W using a 980-nm laser, at 50 W with a 1470-nm laser, and at 6:6 W with a dual-wavelength laser. The dual-wavelength laser demonstrated enhanced cutting efficiency and reduced thermal damage compared to the single-wavelength 980-nm and 1470-nm lasers. Furthermore, it provided superior cutting efficiency, with no significant differences observed in the maximun depth of thermal injury relative to conventional electrosurgical devices. The 980/1470-nm dual-wavelength laser system offers substantial benefits in colorectal surgery, facilitating a more precise and safer surgical technique. This system is distinguished by its enhanced cutting efficiency and reduced thermal damage relative to single-wavelength 980-nm and 1470-nm lasers. Furthermore, when compared to high-frequency electrosurgical instruments, the dual-wavelength laser maintains superior cutting efficiency without an associated increase in thermal damage. Further studies will validate the efficacy and safety of 980/1470-nm dual-wavelength laser-assisted natural orifice transluminal endoscopic surgery and endoscopic submucosal dissection in a live pig colon model and apply them to the clinic.