Necrosis zone depth after bipolar plasma vaporization and resection in the human prostate

OBJECTIVES: To compare the depth of thermal necrosis after use of bipolar resection and vaporization technique comparing intra-individually bipolar loop and bipolar button electrodes. METHODS: Transurethral resection and vaporization of the prostate was performed in 55 male patients (260 specimens in total). In a standardized procedure, a bipolar resection loop was used for resection, and a bipolar button electrode was used for vaporization. Both electrodes were applied in each patient, either in the left or in the right lateral lobe. The depth of necrotic zones in the resected or vaporized tissue of each patient was measured in a standardized way by light microscopy. RESULTS: The mean depth with standard deviation of thermal injury caused by the loop electrode was 0.0495±0.0274 mm. The vaporization electrode caused a mean thermal depth with standard deviation of 0.0477±0.0276 mm. The mean difference of necrosis zone depths between the two types of electrodes (PlasmaButton–resection loop) was −0.0018 mm (p=0.691). CONCLUSION: For the first time, we present directly measured values of the absolute necrosis zone depth after application of plasma in the transurethral treatment of benign prostatic hyperplasia. The measured values were lower than in all other transurethral procedures. Standardized procedures of measurement and evaluation allow a statistically significant statement that the low necrosis depth in bipolar procedures is independent of the applied electrodes.