Stereotactic percutaneous cryoablation for kidney tumor

Abstract

The aim of the study included the development and refinement of the technique of stereotaxic cryoablation to improve the safety and radicalness of the procedure. Cryoablation was performed in 56 patients with a histologically confirmed diagnosis of renal cell carcinoma in 65.5% of patients, its chromophobic variant - in 10.4% of the rest - oncocytoma. Local recurrence was detected in four patients with initial tumor sizes over 30 cm3, who required repeated cryoablation for complete tumor devitalization. We used Russian minimally invasive cryosurgical systems "MKS" with liquid nitrogen, a set of special tools and reusable cryoprobes with a needle diameter of 1.5 mm to 3.0 mm.  The planning of procedure includes projections of the contours of the ice spheres of different cryoprobes were superimposed on the three-dimensional CT image of the tumor, simulating the complete coverage of the tumor by a common ice-balls with the capture of at least 3 mm of kidney tissue and up to 10 mm of perinephric fat. Two navigation options were used during procedure: free or robotic with a navigation CT attachment. In the lumbar region in the zone of surgical approaches were determined directrix.  The directrix - it is one or more sectors for the introduction of instruments and cryoprobes. The angle and depth of each directrix depended on the location of the tumor. After controlling the position of the cryoprobes in the CT room or operating room were performed two cooling cycles with passive thawing, direct thermometry, automatic exposure retention, and visual assessment of the completeness of tumor glaciation The hematoma  after using cryoprobes of 3 mm did not exceed 150 ml and not require additional intervention. The proposed technology ensured the safety and efficiency of precision cryoablation of kidney tumors, thanks to accurate navigation, high power of modern minimally invasive cryogenic equipment and additional training of specialists.