Ice burn: protecting the flank during renal cryotherapy.

Introduction And Objectives: Cryoablation is a viable minimally invasive strategy for the treatment of small renal masses. One of the most common postoperative complaints is pain or paresthesia at the cryoprobe insertion site. The use of a 14-gauge angiocatheter to insulate the flank during renal cryotherapy was investigated.

Materials And Methods: Six Yorkshire swine underwent laparoscopy-guided percutaneous cryoablation of the upper and lower poles of both kidneys with a 1.47 mm (17 gauge) cryoneedle. Treatment consisted of a double 10-minute freeze separated by a 5-minute active thaw. Trials were randomized to placement of the cryoneedle directly through the flank or through a 14-gauge angiocatheter as an insulating sheath. Temperatures were recorded adjacent to the cryoneedle at two depths in the flank with a Multi-Point Thermal Sensor.

Results: Twelve trials were completed each with a bare and sheathed cryoneedle. The coldest temperature observed was -26 degrees C for the bare cryoneedle and -21 degrees C for the sheathed cryoneedle. At the outer sensor, there was a 4.1 degrees C increase in mean temperature for freeze 1, and 6.2 degrees C increase in mean temperature for freeze 2 with sheath use. At the inner sensor, there was a 3.0 degrees C increase in mean temperature for freeze 1, and 9.4 degrees C increase in mean temperature for freeze 2 with sheath use. There was a trend toward statistical significance of sheath insulation at the outer (p = 0.07) and inner (p = 0.08) temperature sensors.

Conclusions: A 14-gauge angiocatheter may provide some insulation and thereby might help protect against "ice burn" during renal cryotherapy.