FANS vs CVAC for Medium to Large Stones

Ureteroscopy (URS) is recommended by the American Urological Association for surgical treatment of kidney stones \< 2 cm in linear dimension. Although historically shock wave lithotripsy was the most common surgical treatment, since 2013 ureteroscopy has become the most common surgical treatment for kidney stones. There have been great advancements to ureteroscopic technology with improvements in laser technology leading to more efficient and complete stone ablation/ fragmentation. However, stone free rates were still suboptimal, with some series reporting stone free rates of 55% after URS. However, in the last couple of years the introduction of suction technology, specifically Flexible and Navigable Suction (FANS) sheaths and the CVAC scope by Calyxo have changed the paradigm of kidney stone treatment. CVAC is essentially a larger ureteroscope with a large 7F working channel that allows for aspiration of stone fragments created during laser lithotripsy. A standard ureteroscope has a working channel of only 3.6 F so fragments cannot be aspirated through this. These new suction technologies allow the surgeon to actively remove stone fragments, thereby increasing the immediate and long-term stone free rate, instead of waiting for fragments to pass after the surgery.