Renal cryoablation and radio frequency ablation: an evaluation of worst case scenarios in a porcine model.
OBJECTIVE
Although ablative technologies, including radio frequency (RF) ablation (RFA) and cryoablation (CA), are being used to treat renal masses, complications associated with injury to vital renal structures are not well understood. We investigated these worst case scenarios by deliberately targeting vital renal structures with CA or RFA in a porcine model.


METHODS
Following surgical exposure of the right kidney in female pigs a cryoneedle or an RF probe was deliberately placed under visual and ultrasound guidance in the renal pelvis (CA in 5 pigs and RFA in 7), major calix (CA and RFA in 5 each) or subsegmental renal vessels (CA in 5 pigs and RFA in 7). Cryo-energy or RF energy was then applied to create a 3 cm lesion. After 10 days the kidneys underwent gross and histological examination for urine and blood extravasation, cell death and injury. Ex vivo retrograde pyelography was performed to evaluate for urinary fistulas.


RESULTS
All pigs tolerated the treatment and no procedure related deaths occurred. No significant bleeding was noted. RFA and CA created reproducible lesions and areas of cell death and necrosis. Despite significant intentional injury to the collecting system no urinary fistulas were demonstrated in CA specimens (0 of 15). In contrast, damage to the renal pelvis (4 of 7) by dry (3 of 4) or wet (1 of 3) RFA was associated with a high likelihood of urinary extravasation.


CONCLUSIONS
This short-term study demonstrates that CA is safe, effective and not associated with urinary extravasation. In contrast, RFA to the renal pelvis is associated with urinary extravasation. Further studies are needed to support these findings.
Brashears
James H
JH
Division of Urology, Duke University Medical Center, Durham, North Carolina, USA.
Raj
Ganesh V
GV
Crisci
Alfonso
A
Young
Matthew D
MD
Dylewski
Drew
D
Nelson
Rendon
R
Madden
John F
JF
Polascik
Thomas J
TJ
D000818:Animals; D017115:Catheter Ablation / Q000009:adverse effects*; D016923:Cell Death / Q000502:physiology; D003452:Cryosurgery / Q000009:adverse effects*; D004869:Equipment Safety; D005119:Extravasation of Diagnostic and Therapeutic Materials / Q000473:pathology; D005260:Female; D007668:Kidney / Q000473:pathology / Q000601:surgery*; D007670:Kidney Calices / Q000293:injuries* / Q000473:pathology; D007682:Kidney Pelvis / Q000293:injuries* / Q000473:pathology; D009336:Necrosis; D012077:Renal Artery / Q000293:injuries* / Q000473:pathology; D025321:Surgery, Computer-Assisted; D013552:Swine; D014463:Ultrasonography; D014548:Urinary Fistula / Q000473:pathology