Regulated high frequency diathermy for bipolar electrocoagulation--a new method for the treatment of carcinoma of the bladder.

In the endoscopic treatment of bladder cancer, especially for stages beyond T2, transurethral resection does not seem to be sufficient. The risk of bladder wall perforation, the possibility of incomplete resection, seeding of tumor cells and high recurrence rates support the former statement [6]. Results of a multicentre prospective randomised study have exemplified that irradiation with the Neodymium-YAG Laser has been a reasonable alternative in the therapeutic approach to bladder cancer [2]. Diathermy coagulation must produce a sufficiently deep, homogeneous and well demarcated tissue necrosis. The coagulation depth has to be adjustable and heat production during coagulation should not lead to bladder wall perforation and consequent damage to the bowel. These criteria were investigated using regulated bipolar high frequency diathermy. The innovation in this method is, that thermal side effects on the tissue, e.g. vaporisation and carbonisation are prevented by a protective relay with constant current flow. Animal experimental studies have shown that this method meets all postulated requirements and therefore clinical trials can proceed.