The microcirculation in neodymium-YAG laser irradiated and in electrocoagulated urinary bladder tumors evaluated with laser Doppler flowmetry.

Neodymium-YAG laser irradiation is a relatively new therapeutic modality for the treatment of urinary bladder tumors which is suggested to produce an instantaneous arrest of the blood circulation and a homogeneous coagulation of the tumor tissue. Utilizing the laser Doppler flowmetry principle the microcirculatory changes in laser irradiated tumors were compared to the changes in tumors coagulated with diathermy. In laser treated tumors the blood cell flux decreased to near baseline levels throughout coagulated area. Vascular stasis was demonstrated in the erythematous zone encircling the necrosis. In tumors coagulated with diathermy a corresponding constant decrease in blood cell flux could not be demonstrated. Thus the neodymium-YAG laser irradiation seems preferable to electrocoagulation in the treatment of urinary bladder tumors as more complete and homogeneous arrest of the blood circulation in the treated area is achieved.