A randomized comparative study of flexible ureterorenoscopy versus mini-percutaneous nephrolithotomy for treatment of renal stones 2 cm or less

Abstract

Background: Flexible ureterorenoscopy (fURS) and mini-percutaneous nephrolithotomy (mPCNL) have been increasingly used for the treatment of renal stones. However, current guidelines do not recommend one modality over the other. The aim of this study is to compare the safety and efficacy of treatment with fURS versus mPCNL for renal stones sized 2 cm or less.

Materials and methods: A prospective, randomized, comparative study was conducted between January 2019 and July 2021 at 3 tertiary care urology centers. Inclusion criteria were adult patients with renal stone(s) ≤ 2 cm with inappropriateness or failure of extracorporeal shock-wave lithotripsy. Subjects were assigned to 1 of 2 treatment groups, either mPCNL or fURS. Two primary outcomes were assessed: (1) initial success rate, defined as the absence of clinically significant residual fragments (>2 mm) on kidney ureter bladder X-ray and ultrasound on the first postoperative day; and (2) complications, which were reported according to the Modified Clavien-Dindo classification system. Secondary outcomes included final success rate, defined as the absence of clinically significant residual fragments on noncontrast computed tomography on the 90th postoperative day; operative time; auxiliary procedures and blood transfusion rates; hemoglobin drop; and length of hospital stay.

Results: One hundred and eighteen procedures were analyzed (59 in each group). The initial success rate of the mPCNL group (93%) was significantly higher than that of the fURS group (70%). Complications occurred more frequently with mPCNL than fURS (44.1% vs. 18.6%, respectively). Final success rate, operative time, and length of hospital stay were comparable between the 2 groups.

Conclusions: Mini-percutaneous nephrolithotomy is more effective than fURS as a single-step treatment for renal stones <2 cm because of its higher initial success rate and lower auxiliary procedure rate. However, mPCNL results in significantly higher complication rates than fURS.

Keywords

Endourology / Flexible ureterorenoscopy / Mini-percutaneous nephrolithotomy / Retrograde intrarenal surgery / Urolithiasis

Acknowledgments

The authors thank Dr Wael Sameh, chairman of the Department of Urology at Alexandria University Hospital, for his administrative cooperation and giving permission to acquire data from the department during the conduct of this study.

Statement of ethics

The study was conducted according to the principles of Declaration of Helsinki and International Conference on Harmonization and Good Clinical Practice (ICH-GCP), registered at ClinicalTrials.gov Protocol Registration and Results System in April 2019 under ID NCT03932370, and was approved by the local Ethics Review Board under number 17200369. All patients signed informed consent prior to participation in the study.

Conflict of interest statement

The authors declare that they have no conflicts of interests.

Funding source

None.

Author contributions

All authors contributed to the study conception and design. Material preparation, data collection and analysis, as well as writing of the first draft of the manuscript, were performed by AD. All authors commented on previous versions of the manuscript and read and approved the final manuscript.

Data Availability

The datasets generated during and/or analyzed during the current study are available from the corresponding author on reasonable request.

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