Experimental study of laparoscopic laser-induced thermotherapy for liver tumours

Laser-induced thermotherapy is a minimally invasive method that can be applied percutaneously or during laparotomy for the treatment of malignant liver tumours. The aim of this experimental study was to investigate whether the laparoscopic approach is suitable for laser-induced thermotherapy. Laparoscopic ultrasonography was tested as an aid to intrahepatic positioning of the applicators as well as for online monitoring during application.

A neodymium yttrium-aluminium-garnet laser was used to induce thermal lesions in the healthy liver of ten German hybrid pigs. The length of application was 840 s. Forty applications were performed with normal hepatic blood flow and 40 with hepatic blood flow interrupted by means of a laparoscopic Pringle's manoeuvre.

A total of 20 simultaneous multifibre applications with 80 single applications were performed. Thermal necrosis with a total volume of 50.3 cm3 was induced with high precision when hepatic blood flow was interrupted temporarily. When hepatic blood flow was normal, the total volume of thermal necrosis was only 14.6 cm3 (P < 0.01). Laparoscopic ultrasonography was used successfully as an aid for exact applicator positioning and for online monitoring. Method-related complications did not occur.

The laparoscopic approach is an attractive means of application for laser-induced thermotherapy and it seems that clinical testing is justified.