Comparison of the thermal and histopathological effects of bipolar and monopolar electrosurgical resection of the prostate in a canine model

OBJECTIVES To compare the thermal and histopathological effects of two commercially available bipolar systems and conventional monopolar transurethral resection of the prostate (TURP) in a canine model. Bipolar TURP is an alternative to monopolar electrosurgery for treating benign prostatic hyperplasia and has several potential clinical advantages, including the ability to use normal saline irrigation, enhanced haemostasis and less collateral thermal damage. MATERIAL AND METHODS In all, 12 adult male beagles were studied. After midline laparotomy and exposure of the bladder and prostate, two fibre-optic thermosensors were placed to record tissue temperatures; one sensor was placed into the substance of the prostate 2 cm from the urethra and the second in the prostatic-rectal groove on the capsular surface of the prostate to measure temperatures in the region of the neurovascular bundles. Through a midline cystotomy, antegrade TURP was performed using two different bipolar systems (Gyrus PlasmaKinetic and Vista, both from Gyrus-ACMI Corporation, Maple Grove, MN, USA) or a monopolar device (ForceTM 2, Valleylab, Boulder, CO, USA). TURP was performed in each lateral lobe using 24 F resection loops. The dogs were humanely killed acutely and the prostates excised for histopathological assessment. RESULTS When comparing intraprostatic temperature data, the mean (sem) temperature changes recorded for the monopolar group were significantly higher than in either the Gyrus or Vista bipolar groups, at 24.2 (3.9) degrees C vs 8.1 (1.5) degrees C and 6.8 (1.8) degrees C, respectively (P < 0.001). No measurable temperature elevations were recorded near the neurovascular bundles with any of the electrosurgery devices. The depth of thermal damage was greatest in the monopolar group at 0.59 (0.27) mm compared with the Gyrus and Vista groups at 0.07 (0.08) mm and 0.15 (0.02) mm, respectively (P < 0.001). CONCLUSION Bipolar TURP generated significantly less heat and histopathological evidence of thermal damage compared with monopolar TURP in the present canine model.