Preliminary experience with cryoablation of renal lesions smaller than 4 centimeters.

Nephron-sparing surgical techniques represent an attractive treatment approach for small renal lesions that are limited only by potential operative morbidity. This study tests the hypothesis that an alternative strategy of in situ cryoablation of these lesions may further reduce the incidence of complications with similar efficacy. Beginning August 1996,17 patients were enrolled in an institutional review board-approved protocol for open renal cryoablation for lesions smaller than 4 cm in diameter. The median age was 62 years (range, 35-75 years). The median preoperative lesion size was 2.0 cm (range, 1.1-4.2 cm) determined with either computed tomography or magnetic resonance imaging. A double freeze-thaw technique to -180 degrees C was used under direct intraoperative ultrasound monitoring. The median length of follow-up was 30 months (range, 10-60 months), with 8 patients followed up for more than 20 months. The procedure was accomplished in 3 hours (range, 2.25-4.25 hours) through a 5-cm to 7-cm subcostal incision. The median blood loss was 100 mL, and the median hospital stay was 2 days (range, 2-8 days). The median intraoperative lesion was 2.4 cm, which was not statistically different from preoperative measurements. Postoperative serum creatinine levels were unchanged except for a transient increase from 5.5 mg/dL to 7.0 mg/dL in one patient. Follow-up magnetic resonance imaging scans have demonstrated infarction and a reduction of lesion size in 15 of 16 cases. The size of one patient's mass was unchanged after 3 months. Renal cryoablation via an open approach is associated with few complications and represents a viable alternative to extirpative surgical techniques. The open exposure provides an accurate assessment of the renal unit with definitive ultrasound visualization.