MONITORING RENAL CRYOSURGERY: PREDICTORS OF TISSUE NECROSIS IN SWINE

AbstractPurpose: To examine parameters for monitoring renal cryosurgery and correlate with histopathologic necrosis in a porcine model. Parameters include: 1) tissue temperature, 2) distance of tissue from the cryosurgical probe insertion site, and 3) inclusion of tissue by the visible iceball.Materials and Methods: Following midline incision, 6 healthy kidneys from 3 domestic pigs were treated using a nitrogen-based cryosurgical system with 3.4 mm outer diameter cryoprobe. Temperatures were monitored at 6 sites in each kidney using prototype thermocouples. Gross and histologic analysis was performed on tissue harvested from each thermosensor site 24 hours postoperatively.Results: All animals survived to complete the full protocol. Post-procedure bleeding was managed surgically. Histopathology revealed that complete ablation was uniformly produced at temperatures of −19.4C or lower in 13/13 tissue samples. Within 16 mm. of the probe insertion site, cells were uniformly ablated in 17/17 samples while degre...