Kidney stone treatment symbolized by tiny doctors inside a kidney.

Kidney Stone Treatment: Is More Always Better? The Volume-Outcome Link

Mira Elwood in Health & Wellness December 2025 • 4 min read.

"New research suggests a critical number of annual procedures could significantly improve patient outcomes in ureterorenoscopic stone treatment."

Kidney stones are a prevalent health issue, with cases on the rise globally. Ureterorenoscopy (URS), a minimally invasive procedure, is a common treatment. However, with the increasing use of URS, it's essential to understand what factors contribute to its success. Is it simply the technology, or does the experience of the medical team play a more significant role?

In various medical fields, the idea that higher procedure volumes lead to better patient outcomes is well-established. But what about URS? A recent study from Germany, the BUSTER-Trial, sheds light on this question. It explores the relationship between a hospital's URS volume and patient outcomes, seeking to define a threshold for optimal results.

This article breaks down the BUSTER-Trial findings, explaining how hospital volume affects stone-free rates and complication occurrences. Whether you're a patient exploring treatment options or someone simply curious about healthcare quality, understanding the volume-outcome link is crucial.

The Magic Number: 99 URS Procedures Annually

Kidney stone treatment symbolized by tiny doctors inside a kidney.

The BUSTER-Trial, a prospective observational study, collected data from 307 patients undergoing URS across 14 German hospitals. Researchers looked at various factors, including stone-free rates (complete removal or fragments small enough to pass), complication rates, and the annual number of URS procedures performed at each hospital.

The study revealed a significant correlation between hospital volume and successful outcomes. Here's what they found:

Threshold Identified: Hospitals performing 99 or more URS procedures annually demonstrated significantly better outcomes.
Higher Success Rate: In hospitals exceeding this threshold, 92.9% of patients achieved the desired outcome (stone-free or small residual fragments with minimal complications), compared to 78.2% in lower-volume hospitals.
Adjusted Advantage: Even after accounting for patient-specific factors (age, sex, BMI), stone characteristics (size, location), and physician experience, a higher hospital volume independently increased the chance of a successful outcome.

This suggests that experience and established protocols gained from performing a higher number of procedures contribute to improved patient care and outcomes. But why this number? It likely represents a point where the medical team has refined their techniques, streamlined processes, and developed expertise in managing potential complications.

What This Means for Patients

The BUSTER-Trial provides valuable insights for patients seeking kidney stone treatment. While it's crucial to remember that individual patient factors play a significant role, considering hospital volume could be another piece of the puzzle.

It's important to have an open discussion with your urologist about their experience and the resources available at the hospital or clinic. Don't hesitate to ask about the number of URS procedures they perform annually and what protocols they have in place to ensure patient safety and optimal outcomes.

Ultimately, the best treatment decision is a collaborative one, made with a qualified medical professional who understands your individual needs and circumstances. While higher volume may suggest a greater likelihood of success, a skilled surgeon in a lower-volume setting can still deliver excellent care.

About this Article -

This article was crafted using a human-AI hybrid and collaborative approach. AI assisted our team with initial drafting, research insights, identifying key questions, and image generation. Our human editors guided topic selection, defined the angle, structured the content, ensured factual accuracy and relevance, refined the tone, and conducted thorough editing to deliver helpful, high-quality information.See our About page for more information.

This article is based on research published under:

DOI-LINK: 10.1007/s00345-018-2431-3, Alternate LINK

Title: Hospital Volume In Ureterorenoscopic Stone Treatment: 99 Operations Per Year Could Increase The Chance Of A Better Outcome—Results Of The German Prospective Multicentre Buster Project

Subject: Urology

Journal: World Journal of Urology

Publisher: Springer Science and Business Media LLC

Authors: Steffen Lebentrau, Thomas Enzmann, Mike Lehsnau, Frank Christoph, Martin Schostak, Matthias May

Published: 2018-08-09

Everything You Need To Know

What exactly is Ureterorenoscopy (URS), and what factors influence how well it works?

Ureterorenoscopy, or URS, is a minimally invasive surgical procedure commonly used to treat kidney stones. It involves using a small scope to locate and remove or break up stones within the urinary tract. The effectiveness of URS can vary based on factors such as the size and location of the stone, the patient's anatomy, and the experience of the medical team performing the procedure.

According to the BUSTER-Trial, how does the number of URS procedures a hospital performs each year affect patient outcomes?

The BUSTER-Trial indicates that hospitals performing 99 or more URS procedures annually tend to have better patient outcomes. Specifically, these hospitals demonstrated a higher success rate in achieving stone-free status or leaving only small residual fragments with minimal complications. This suggests that a higher volume of procedures allows medical teams to refine their techniques and develop expertise in managing potential complications.

Does the study consider treatment options other than Ureterorenoscopy, like shock wave lithotripsy, and how do they compare?

The BUSTER-Trial primarily focused on Ureterorenoscopy. While other treatments like shock wave lithotripsy (SWL) and percutaneous nephrolithotomy (PCNL) exist, the study didn't directly compare these. Choosing the right treatment depends on stone size, location, and patient health. Further research would be needed to determine if a similar volume-outcome relationship exists for other kidney stone treatments.

Does the BUSTER-Trial imply that the hospital's overall experience matters more than an individual surgeon's experience in URS procedures?

The BUSTER-Trial suggests a higher hospital volume performing URS is linked to better outcomes, even after accounting for patient and stone characteristics. This implies that the hospital's overall experience and established protocols contribute to successful treatment. While individual physician experience is important, the study highlights the benefits of a well-coordinated and experienced medical team.

Considering the volume-outcome relationship found in the BUSTER-Trial, what are the implications for where URS procedures should be performed to maximize patient success?

The BUSTER-Trial highlights that hospitals performing a higher volume of Ureterorenoscopies, specifically 99 or more annually, demonstrated better patient outcomes. This suggests that concentrating URS procedures in specialized centers could improve overall treatment success. Further investigation is needed to explore logistical and geographical access challenges, and whether regionalizing URS services leads to improved patient care across the board.