RENAL CRYOTHERAPY IN A SHEEP MODEL - A FEASABILITY STUDY

Purpose: This study was designed to evaluate the safety and efficacy o f renal cryotherapy as a possible treatment of renal malignancy with p reservation of renal parenchyma. Materials and Methods: Ten Merino she ep were anaesthetised and the right kidney was exposed through a retro -peritoneal approach. A 5 mm. cryotherapy probe (LCS 3000 Cryotec UK) was inserted into the lower pole of the kidney and freezing was undert aken to form an iceball 5 cm. in diameter. Results: There was no morta lity and no complications were observed. A transient rise in creatinin e was observed post-operatively. The sheep were euthenased at 4 weeks and at necropsy macroscopic examination revealed a contracted, fibroti c wedge shaped lesion of 3 cm in diameter. Histological examination of the ''cryolesion'' revealed a central area of coagulative necrosis an d a 5 mm rim of partial necrosis with preservation of renal tubules. C onclusion: We conclude that renal cryotherapy is safe and can achieve effective renal necrosis in the sheep model.