Relocation and evacuation of stone fragments using 7.5 Fr flexible ureteroscope with direct-in-scope suction: an experimental study.

Introduction: Aim of the study was to evaluate and illustratively depict the aspiration properties of a single-use 7.5 Fr flexible ureteroscope with direct-in-scope suction (DISS) in a specifically designed in vitro setting.

Material and methods: An experimental in vitro study using a 6.5 size sterile glove, natural stone fragments and part of a porcine ureter was performed. A single use 7.5 Fr digital flexible ureteroscope with integrated direct-in-scope suction (PU3033AH, Zhuhai Pusheng Medical Technology Co., Ltd., Zhuhai China) was used for all trials. Five stone fragments ranging from 3 to 5 mm in maximal diameter were used. For each stone, three trials were performed; stones placed in the upper, middle and lower calyx. The experimental trial was defined as partially successful if stone relocation using suction (SRS) was present and successful when subsequent evacuation was reported.

Results: Relocation of stone fragments (partial success) was observed for all stones in different locations. Easy evacuation of the 3 mm stone fragment occurred from all calyces. Complete success was also reported for all 4 mm stones. Complete success was documented with the 5 mm stone positioned in the upper and middle calyces, whereas evacuation of the stone from the lower calyx was not achieved after 5 attempts.

Conclusions: With the 7.5 Fr Pusen DISS integrated scope, stone fragments 3-5 mm in all calyces were successfully relocated. Whilst evacuation from any calyx was successfully done in 3-4 mm fragments, this was only possible for 5 mm fragments located in upper calyx or interpolar region. The lower pole and greater fragment size need further evaluation for optimal management by DISS.