[Ultrasound-guided cryotherapy of small renal masses: Systematic review.]

Renal cryotherapy (RC) is an alternative therapeutic option to partial nephrectomy in elderly patients and/or patients with comorbidities. The technique can be guided by ultrasound, CT and MRI. Although CT is the most used technique, there are no comparative studies. The objective of this study was to review the current status of ultrasound as a guide for the planning and execution of RC.

A systematic review of the literature was carried out in the Pubmed/Medline database following the PRISMA guidelines. We used 42 articles that met the inclusion criteria for the synthesis of the evidence.

Ultrasound allows dynamic and real-time monitoring of the entire procedure to guide the biopsy, placement of the cryoprobes, cryoball formation, and early identification of complications. The success rate and recurrences found in the percutaneous renal cryotherapy (PRC) were 97.04% and 1.81%, respectively, with 9.35% complications. The ultrasound during laparoscopic renal cryotherapy (LRC) has been shown to reduce the time spent in localizing the renal mass and also decreases the need for large dissections. On the other hand, contrast-enhanced ultrasound during follow-up shows a concordance with the CT or MRI of 72-96% and no complications have been described associated with its execution.

Renal cryotherapy guided by ultrasound is a feasible technique, its main advantage is based on real-time monitoring during the procedure. The PRC presents an acceptable rate of complications and excellent oncological results. The LRC allows a rapid localization of the renal mass and reduces extensive dissections. During follow-up, the use of contrast ultrasound is a safe alternative that has been shown to have a good degree of agreement with respect to CT and MRI.