Is the direct in-scope suction (DISS) the solution for the non-prestenting and sheathless flexible ureteroscopy?

The concept of suction has revolutionized the modern endourology. Direct in-scope suction (DISS) allows for simultaneous or alternating suction and aspiration during the endoscopic laser lithotripsy, using the scope as a conduit to aspirate fine dust or fragments from all the renal calyxes. This study aimed to evaluate the feasibility, safety, and effectiveness of DISS in non-prestented and sheathless flexible ureteroscopy.

A retrospective study was conducted of consecutive patients undergoing DISS at the Hospital Aleman of Buenos Aires between March 2025 and September 2025. We included patients with non-complex kidney stones and those in whom a suction ureteral access sheath was not used and who did not have a ureteral stent before the procedure. A 7.5Fr disposable flexible scope (PU3033AH) was used. Stone-free rate (SFR) was defined according to a 4-week postoperative low-dose non-contrast computed tomography scan as Grade A = absence of stone fragments, Grade B = stone fragments <  = 2 mm, and Grade C = stone fragments > 2 mm. Postoperative complications were evaluated according to the Clavien-Dindo classification.

In all, 81 patients were included. The mean stone volume was 582 mm3 (353-858). Thulium Fiber Laser was used in 79.0% and Magneto-Ho:YAG pulse modality in the remaining 21.0%. Total operative time was 40 min (35-45 min) and a postoperative double-J stent was placed in 84.3%. The Grade A SFR was 86.4% and Grade B 13.6% with no patients in Grade C definition. The overall postoperative complications rate (Clavien-Dindo ≤ 2) was 8.6% with no major complications.

DISS without the use of a ureteral access sheath and no preoperative double-J stent placement is effective and safe in selected patients. Further clinical trials are needed to reaffirm the results obtained in this initial experience.