RESUMO
BACKGROUND: Laser hemorrhoidoplasty (LHP) is a new technique for treatment of hemorrhoids. The exact extent of coagulation is not visible at the time of the procedure. There currently is no experimental or clinical data on the subject. OBJECTIVE: To evaluate the length of coagulation defect according to power and activation time of 1470nm diode laser on the perianal tissue model. METHODS: Fresh anorectal tissue of twenty-four pigs was used to produce 54 experimental samples. Each sample was randomly assigned to the laser power of 6, 8 and 10 W and 1, 2 or 3-second pulses. The procedure was performed using Biolitec Ceralas © diode laser with 1.85 mm optical fiber. The fiber was inserted in a manner, similar to intrahemorrhoidal laser application. Samples were evaluated using low-power and high-power light microscopy by a single pathologist. The length of tissue injury was measured on high-magnification microscopy. RESULTS: The longest tissue injury (mean 3.93 mm) was caused by the longest laser exposure time (3 sec) with no significant difference between laser power used. CONCLUSIONS: 8 W 3-second application of the 1470nm diode laser results in coagulation area approximately 4 mm, and further coagulation should be initiated approximately 5 mm from the first one.