Hydrodisplacement in the percutaneous cryoablation of 50 renal tumors

OBJECTIVE. The purpose of this article is to describe the technique, safety, and effectiveness of percutaneous hydrodisplacement during the course of percutaneous renal cryoablation. MATERIALS AND METHODS. We retrospectively reviewed our experience in performing percutaneous hydrodisplacement during the cryoablation of renal tumors. In this subset of patients, we addressed tumor location within the kidney, tumor position relative to critical structures, effectiveness of hydrodisplacement, and complications in performing this adjunct technique. Comparisons between the two groups were made using Wilcoxon's rank sum test or chi-square test, as appropriate. RESULTS. Hydrodisplacement was attempted 52 times in 50 (24%) of 206 percutaneous renal tumor cryoablations. Tumors that were located anteriorly (p < 0.0001) or in the lower pole (p = 0.001) of the kidney were more likely to require hydrodisplacement. The colon required displacement most often (n = 41), followed by the body wall (n = 3), duodenum (n = 2), jejunum and ileum (n = 2), ureter (n = 1), and psoas muscle (n = 1). There was a single complication of hemorrhage resulting from injury to an intercostal artery branch that required termination of the procedure before fluid infusion. When fluid was infused, the critical structure was displaced in 50 (96%) of 52 attempts, displacing the critical structure from its initial location by a mean distance of 16 mm (range, 3-46 mm). Both failures occurred early in our experience with hydrodisplacement, and both required balloon displacement. CONCLUSION. Hydrodisplacement is a safe, effective, and commonly needed technique for displacement of critical structures before percutaneous cryoablation of renal tumors, particularly for tumors located anteriorly or in the lower pole of the kidney.