Acute and chronic interstitial cryotherapy of the adrenal as a treatment modality

Adrenalectomy is indicated for patients with large adrenal lesions or funct ional tumors. Cryoablation is currently used as a surgical alternative for the treatment of prostate, lung, brain, pharynx, and liver tumors The purpo se of this study was to determine if cryosurgery could be delivered to smal l areas in the adrenal gland in a controllable and reproducible manner such that tissue could heal in a nonpathologic way. A total of 14 female mongre l dogs underwent acute (n = 8) or chronic (4 weeks, n = 6) cryoablation usi ng the Cryo-unit. In the acute study using an open transabdominal approach a 2-mm cryoprobe was placed interstitially into the adrenal tissue, whereas 0.032-inch thermocouples were cannulated into the ipsilateral adrenal arte ry and vein. Adrenal parenchymal temperature changes were measured using 0. 032-inch thermocouples placed at 0.4- and 0.8-cm intervals from the cryopro be. In the chronic study, cryoablation was achieved by transperitoneal lapa roscopic access using a standard laparoscopic technique. Interstitial cryop robe temperatures decreased from 33.1 +/- 1.9 degrees C to -148 +/- 1.2 deg rees C following 15 min of freezing in the acute study. Cryoablation of adr enal tissue achieved temperatures of -41.8 +/- 5.7 degrees C and -21.8 +/- 1 degrees C at distances of 0.4 and 0.8 cm from the cryoprobe, respectively . There was no significant change in adrenazl artery or vein temperatures d uring cryoablation. Histologically there is a clear demarcation between via ble and nonviable tissue characterized by areas of multifocal hemorrhage an d pyknosis. After 4 weeks of healing a well-defined line of necrotic and vi able tissue is visible. Cryoablation of the adrenal can be delivered in an effective, controllable, and reproducible manner. This controllable energy form may provide a new treatment modality for tissue destruction where adre nal gland preservation is necessary and can be performed by the laparoscopi c approach. Understanding the effect of adrenal cryoablation may allow us t o treat selected patients with small tumors where organ preservation is nec essary.