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

Background and Objectives: Adrenalectomy is indicated for patients with lar ge adrenal lesions or functional tumors. Cryoablation is currently used as a surgical alternative for the treatment of prostate, lung, brain, pharynx, and liver tumors. The purpose of this study was to determine if cryosurger y could be delivered to small areas in the adrenal gland in a controllable and reproducible manner, so that tissue could heal in a nonpathological way , Materials and Methods: Fourteen female mongrel dogs underwent acute (N = 8) or chronic (4 weeks) (N = 6) cryoablation using the Cryounit, In the acute study, using an open transabdominal approach, a 2-mm cryoprobe was placed interstitially into the adrenal tissue, while 0.032-inch thermocouples were cannulated into the ipsilateral adrenal artery and vein, Adrenal parenchym al temperature changes were measured using thermocouples placed at 0.4- and 0.8-cm intervals from the cryoprobe, In the chronic study, cryoablation wa s achieved by transperitoneal laparoscopic access using standard laparoscop ic technique. Results: Interstitial cryoprobe temperatures decreased from 33.1 +/- 1.9 de grees C to -148 +/- 1.2 degrees C following 15 minutes of freezing in the a cute study. Cryoablation of adrenal 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 f rom the cryoprobe, respectively. There were no significant changes in adren al artery or vein temperatures during cryoablation. Histologically, there w as a clear demarcation between viable and nonviable tissue, the latter bein g characterized by areas of multifocal hemorrhage and pyknosis. After 4 wee ks of healing, there was a well-defined line between necrotic and viable ti ssue, Conclusion: Cryoablation of the adrenal gland can be obtained in an effecti ve, controllable, and reproducible manner, This controllable energy form ma y provide new modality for tissue destruction where adrenal gland preservat ion is necessary and can be delivered by the laparoscopic approach. Underst anding the effect of adrenal cryoablation may allow us to treat selected pa tients with small tumors in whom organ preservation is necessary.