Transurethral bladder cryoablation in the porcine model.
OBJECTIVE
To examine the feasibility of transurethral, focal, full-thickness bladder wall cryoablation in the porcine model using a novel 38-cm cryoablation probe.


METHODS
A total of 18 pigs were divided into three groups. Groups 1 (n = 6) and 2 (n = 6) underwent transurethral bladder wall cryoablation in a saline environment with two freeze-thaw cycles. The pigs in groups 1 and 2 were killed after 1 and 3 weeks, respectively. The pigs in group 3 (n = 6) underwent transurethral cryoablation after the bladder had been insufflated with carbon dioxide gas. The pigs in group 3 were killed after 1 week. In all groups, laparoscopic access was obtained to protect the abdominal contents from the transmural cryoablation process. Bladder integrity was evaluated with cystography and laparoscopic visualization, and each cryolesion was excised en bloc for extensive histopathologic evaluation.


RESULTS
All 18 pigs successfully underwent bladder wall cryoablation. For all groups, the preoperative, postoperative, and sacrifice cystograms were without evidence of extravasation. No urinomas, hematomas, or adhesions were present in groups 1 and 2. Minimal adhesions were identified in 3 (50%) of 6 pigs in group 3. For groups 1, and 2, the mean length and width of the area of complete necrosis on histopathologic evaluation was 6.5 and 3.0 mm and 2.3 and 1.3 mm, respectively. For group 3, the mean diameter of the cryolesion was 8.2 mm. Full-thickness necrosis was confirmed in all groups.


CONCLUSIONS
The results of our study have shown that, in this model, complete full-thickness transurethral bladder wall cryoablation, with maintenance of bladder wall integrity, is feasible.
Hruby
Gregory W
GW
Department of Urology, Columbia University Medical Center, New York, New York 10032, USA.
Marruffo
Franzo
F
Ortiz
Jorge
J
Durak
Evren
E
Edelstein
Andrew
A
Levi
Gabriel
G
Landman
Jaime
J
D000818:Animals; D003452:Cryosurgery / Q000379:methods*; D015653:Cystectomy / Q000379:methods*; D005240:Feasibility Studies; D013552:Swine; D014521:Urethra