Bladder cryoablation in a porcine model: Evaluation of three surgical approaches and cryolesion predictability

Purpose: To determine the feasibility of bladder cryoablation (BC) applied laparoscopically, percutaneously, and transurethrally in a porcine survival study. The expected and observed area of cell death after BC was also examined. Materials and Methods: Nine pigs were divided equally into the three treatment groups. Cryoablation was performed with two freeze-thaw cycles after the bladder had been insufflated with CO ₂. Each animal was observed for 7 days after the procedure for treatment-related complications. After cystectomy, each specimen was examined pathologically to determine the degree and dimension of cell death achieved. Results: BC applied via the laparoscopic and percutaneous approach is feasible and safe. No BC-related complications occurred in these two groups. A complication resulting from BC developed in all three animals that were treated cystoscopically, including two intraperitoneal bladder perforations at the time of BC necessitating immediate sacrifice, and one enterovesical fistula discovered at cystectomy. Transmural necrosis was demonstrated in seven of seven animal specimens that survived to the end of the protocol. The observed diameter of tissue necrosis was highly predictable based on the reported cryoprobe isotherms given by the manufacturer. Conclusion: All locations within the bladder can be successfully and predictably treated with cryoablation. Of the three approaches, laparoscopically administered BC appears to be the most safe and consistent method. Transurethral BC was not safe with the equipment available without laparoscopic assistance to prevent bowel complications.