Presented by: Victoria Jahrreiss MD
University Hospital Southampton NHS Foundation Trust

Introduction

The role of ureteroscopy in stone treatment has expanded over the last decades, proving its efficacy and versatility even in difficult clinical scenarios. Dusting and pop-dusting techniques with Holmium:YAG laser represent an excellent surgical option to treat large renal stones. Our aim was to assess safety and efficacy of dusting and pop-dusting for renal and ureteric stones >15 mm using a high power Holmium laser.

Materials

We analysed a cohort of patients with stones >15mm treated with either a 60W Moses or 100 W Holmium:YAG laser from 2016 to 2022. Patients were treated with a standardised approach including the use of ureteral access sheath(UAS) according to the surgeon’s preference (9.5/11.5F or 12/14F). The pop-dusting technique combines an initial dusting modality (0.4-0.8J, 20-30Hz) with a subsequent non-contact lithotripsy (0.5–0.7J, 30–50Hz). A 6 Fr JJ ureteric stent was placed in most cases. Primary outcomes were stone free rate(SFR) and complication rate(CR). The effect of pre- and intra-operative variables on the primary outcomes was also evaluated. SFR was defined as complete endoscopic stone clearance or ≤2 mm fragments on postoperative imaging.

Results

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Overall, 201 patients and 222 procedures were included with a median age of 60. Single and cumulative stone size were 18mm and 22.4mm respectively with 136 patients(67.8%) having multiple stones. The initial and final SFR was 84.5% and 94% respectively with 20(9%) needing a completion ureteroscopy. The median operative time was 54 minutes (37-64.5) and a UAS was inserted in 44.8%. Over a median follow up of 12 months (1-24) the overall CR was 3.4% (7/201), including 6 urosepsis requiring IV antibiotics (Clavien Dindo II) and 1 urosepsis requiring intensive care (Clavien Dindo IVa). A binomial logistic regression was performed to assess the effects of age, pre-operative stenting, total stone length, UAS use and post-operative stenting on SFR and CR. Pre-operative stented patients had 3.26 times higher chances of being stone free (p=0.011); the use of UAS added 0.34 likelihood to SFR (p=0.015). Having a positive urine culture added a risk of 8.5 on the onset of complications (p<0.01).

Conclusion

Our study confirms the safety and effectiveness of ureteroscopy and pop-dusting technique in treatment of large upper urinary tract stones with excellent outcomes.

Funding

None

Lead Authors

Francesco Ripa, MD
University Hospital Southampton NHS Foundation Trust

Co-Authors

Clara Cerrato, MD
University Hospital Southampton NHS Foundation Trust

Carlotta Nedbal, MD
University Hospital Southampton NHS Foundation Trust

Virginia Massella, MRCS
University Hospital Southampton NHS Foundation Trust

Amelia PIetropaolo, MD
University Hospital Southampton NHS Foundation Trust

Bhaskar Somani, MRCS, FEBU, DM, FFSTEd, FRCS (Urol)
University Hospital Southampton NHS Foundation Trust