Laser ablation of normal porcine liver with the 805-nm diode laser and a diffuser fiber

The ability of the 1.06 Nd:YAG laser and the 805 nm diode laser to transurethrally and interstitially ablate prostate has been well documented by this lab and others. With the introduction of lower cost and physically smaller diode laser systems, and the potential for transcatheter and laparoscopic delivery of laser energy through diffuser fibers, laser ablation of tumors of the liver is feasible and could prove to be a cost effective treatment for this and other soft tissue applications. This study examined the acute pathologic effect of 805 nm diode laser radiation delivered via diffuser fibers on normal porcine liver. After preliminary dosimetry parameters were established in cadaveric canine liver, laparotomies were performed to expose the liver on domestic swine. Histopathological samples taken 3 hours after lasing revealed 4 distinct zones of tissue change. The outermost zone showed a 2 mm band of hemorrhage with disruption of hepatic cords adjacent to a zone of disruption of hepatic cords without hemorrhage. Working toward the fiber the next zone was intact with no visible changes. The innermost zone that was in contact with the fiber exhibited a very thin area of necrosis and char. The diameter of the outermost zone seemed to increase with increased wattage.