Topic: Kidney Stones

PCNL: Obtaining Access and Preventing Infection

by Benjamin K. Canales, MD, MPH | Jun 2023

Benjamin K. Canales, MD, MPH, discusses Percutaneous Nephrostolithotomy (PCNL), how to mitigate the risk of SIRS and sepsis associated with the operation, and various techniques used to perform the PCNL. In this presentation, Dr. Canales discusses, the importance of prophylactic antibiotics in infection prevention and mitigation, the history of PCNL, the risks and benefits of various sites for obtaining renal access, and the pros and cons of the known techniques for performing PCNL.

Recent Development of RIRS in Robotic Platforms

by Sung Yong Cho | Aug 2022

Sung Yong Cho, MD, PhD, Clinical Full Professor of Urology at Seoul National University Hospital in Seoul, South Korea, discusses advances in robotic platforms for retrograde intrarenal surgery (RIRS). Conventional RIR presents a number of challenges to both patient and surgeon while robotic-assisted RIR is affected only by patient respiration and irrigation.

Mini PCNL versus Standard PCNL

by Manoj J. Monga, MD, FACS | Mar 2022

Manoj J. Monga, MD, FACS, Professor and Chair of Urology at the University of California, San Diego, compares mini percutaneous nephrolithotomy (mini PCNL) for renal stone removal to standard percutaneous nephrolithotomy (PCNL). He begins by looking at who needs a PCNL, explaining that he typically performs them on patients with a stone larger than 15mm, but that he also sometimes performs PCNL on stones when there are anatomical considerations that would make it difficult to get to the stone ureteroscopically. Dr. Monga notes that PCNL has the best outcomes and results in the best quality of life of any stone removal technique. He then poses the question: Why not treat every stone with PCNL? The answer, of course, he says, is because 4/1000 patients die from PCNL due to sepsis. Dr. Monga then moves on to discuss mini PCNL, noting that it was originally assumed to potentially be safer than PCNL, but that a 2001 study showed there was no advantage. He also observes that the smaller sheath used in mini PCNL actually increases the risk of infectious complications, and that outcomes are worse and operating room time is longer with mini PCNL compared to standard. However, Dr. Monga notes, there does appear to be a lower risk for bleeding and fewer transfusions, which might result in less kidney volume loss.

Asymptomatic Stones: Treat or Observe?

by Manoj J. Monga, MD, FACS | Mar 2022

Manoj J. Monga, MD, FACS, Professor and Chair of Urology at the University of California, San Diego, suggests a situational approach to asymptomatic renal stone treatment based on outcomes data. Dr. Monga explains that asymptomatic renal stones are very common and are diagnosed in some 2 million patients per year. He notes that asymptomatic stones cause significant psychological distress in patients, and in fact tend to worry more than other stone patients. Dr. Monga also clarifies that asymptomatic stones often do not remain asymptomatic, citing data published in the Journal of Endourology showing that 26% of patients ultimately require intervention, 48% experience pain, 55% experience stone growth, and 77% experience any of the previously stated outcomes within 4 years of an asymptomatic stone being identified. He then shows that risk can be further stratified based on stone size and location, explaining that a stone in the renal pelvis is guaranteed to progress while a small upper pole stone is more likely to pass. Dr. Monga states that in most cases asymptomatic stone patients should be treated. He then summarizes the different treatments available for renal stones, observing that patients tend to select the less-invasive shockwave treatment over ureteroscopy even though it is less effective. He states that shockwave treatment’s efficacy varies based on the location and size of the stone, and that this should be discussed with patients. Dr. Monga concludes that stones less than 4mm should be observed and those between 4mm and 10mm should undergo shockwave treatment, while larger stones may require ureteroscopy.

Immunotherapy for NMIBC: Emerging and Expanding Indications

by Jennifer M. Taylor, MD, MPH | Mar 2021

Jennifer M. Taylor, MD, MPH, Assistant Professor of Urology at Baylor College of Medicine in Houston, Texas, reviews new indications for immunotherapy for non-muscle invasive bladder cancer (NMIBC). She discusses the most common immunotherapy option, presents active clinical trials, and evaluates new treatment options. AUA guidance has previously stated that immunotherapy should be reserved for highest-risk NMIBC, and that for lower-risk cancer, patients and clinicians should weigh the benefit ratio when considering whether immunotherapy is an appropriate treatment choice given the possibility of adverse events. However, a shortage of the most common intravesical immunotherapy, bacillus Calmette-Guerin (BCG), in combination with increased numbers of BCG-unresponsive patients, have altered the treatment landscape. Dr. Taylor reviews the 2018 definition of BCG-unresponsive NMIBC and identifies several ways to determine whether a patient is BCG-unresponsive. Finally, she discusses the approval of pembrolizumab as a newly-available treatment for BCG-unresponsive NMIBC. In the study that led to the approval, 41% of patients had a complete response and no patients progressed to muscle invasive bladder cancer or metastasis. These favorable results are notable given that the gold-standard alternative is radical cystectomy. Additionally, pembrolizumab is well-tolerated and while adverse immune-related events are serious, they are rare and can be managed. Other treatments are also currently under investigation.

Guideline-Based Approach to Metabolic Stone Management for the General Urologist

by Wesley A. Mayer, MD | Feb 2021

Wesley A. Mayer, MD, Associate Professor of Medicine at Baylor College of Medicine in Houston, Texas, discusses the AUA guidelines for the medical management of kidney stones, also known as nephrolithiasis. There are 27 guidelines, fitting into the categories of evaluation, diet therapy, pharmacologic therapy, and follow-up. Dr. Mayer urges urologists to care for the whole patient, and to not just focus on the surgical issue. Nephrolithiasis is both a surgical and medical disease, making follow-up with these patients essential. For example, urologists can use a metabolic work-up to reduce the risk of future stone formation. Dr. Mayer concludes by reemphasizing that stone management often requires multiple modalities, including diet and medication, and by noting that for complex cases, urologists may want to consider referring patients to a dietician or other expert.

A Better Mousetrap: Minimally-Invasive Management of Symptomatic Caliceal Diverticular Stones in the Era of Robotic Surgery

by Richard E. Link, MD, PhD | Dec 2020

Richard E. Link, MD, PhD, Professor of Urology and the Carlton-Smith Endowed Chair in Urologic Education at the Baylor College of Medicine, discusses the pros and cons of different techniques for managing caliceal diverticular stones, a simple problem requiring a complex solution. The presentation aims to provide a framework for the identification and management of this condition since there are not enough high-quality studies to have a definitive strategy. Dr. Link discusses caliceal diverticulum incidence, etiology, and presentation, as well as the specific qualities of stones in caliceal diverticula, noting that stone formation is not caused by the presence of a caliceal diverticulum, but rather by the same metabolic anomalies experienced by other stone formers. He then dissects the different surgical options for treatment, including: extracorporeal shockwave lithotripsy (ESWL), which results in stone-free rates of ≤25% and should only be used in patients who cannot tolerate more effective therapy; ureteroscopic management, which is superior to ESWL but still has low success rates; and percutaneous management, which was the gold standard treatment before the era of robotic surgery, and results in a stone-free rate between 70 and 100%, although it can be a challenging surgery. Dr. Link also discusses laparoscopic diverticulectomy and robotic true partial nephrectomy, more aggressive approaches that may be needed if percutaneous management fails. He concludes with several case studies, emphasizing that treatments should be tailored to individual patients.

Renal Stones: To Dust or to Basket?

by Nicole L. Miller, MD, FACS | Aug 2020

Nicole L. Miller, MD, FACS, discusses the pros and cons of dusting versus basketing renal stones. She evaluates cost, time, safety, and recurrence with both procedures. The benefits of dusting include decreased procedure time, decreased disposables, lower cost, and comparable complications. The benefits of fragmentation and basketing include obtaining stone composition, improved stone-free rates, clear benefits in specific populations, and versatility with laser machines. The goals of a successful stone surgery are maximum efficiency, being stone-free, safety, and lowest cost. Looking at the type of stone and the patient will determine which method is best to use.

Breaking Bad: Advances in Laser Lithotripsy Techniques

by Nicole L. Miller, MD, FACS | Jul 2020

Nicole L. Miller, MD, FACS, Associate Professor of Urology at Vanderbilt University Medical Center, discusses AUA guidelines for the treatment of ureteral stones, and compares and contrasts them to the EAU guidelines, examining several cases to illustrate similarities and differences in treatment approaches. She observes that the EAU guidelines are updated more frequently than the AUA guidelines, which often puts them ahead in terms of pain management. Dr. Miller emphasizes that shock wave lithotripsy (SWL) treatment has the least morbidity and lowest complication rate, but ureteroscopy (URS) has a higher stone-free rate in all ureteral locations. She discusses which special cases would be best treated with URS, and why a ureteral stent is not necessary after uncomplicated URS. Finally, Dr. Miller looks at how multimodal therapy for stent pain can significantly reduce narcotic usage.

Endourological Stone Management: Complicated Cases

by Jens Rassweiler, MD | Jul 2020

Jens Rassweiler, MD, Professor and Head of the Department of Urology at Klinikum Heilbronn, the academic hospital of Heidelberg University in Germany, discusses the management of complicated cases of endourological stones. First, he defines what exactly makes a case complicated, and then goes on to detail the procedures involved. He compares various management methods, noting the pros and cons of each and emphasizing the importance of staying away from open surgery when possible. He does discuss the best techniques for open surgery when it is unavoidable, but emphasizes that a combination of robotic and laparoscopic surgery is best.

The Implications of the Microbiome on Stone Pathophysiology, Stone Prevention and Novel Diagnostics

by Aaron W. Miller, PhD | Jan 2020

Manoj Monga, MD, and Aaron W. Miller, PhD, discuss the effect of the microbiome of the gut and urinary tract on the development and prevention of stone disease. Dr. Miller discusses research into oxalate metabolism in the gut that can lead to kidney stones, how the bacteria lactobacillus crispatus may reveal clues about metabolites that can help prevent the incidence of stones, as well as a strain of E. coli that may be connected to their increase.

Mini and Ultra-Mini Percutaneous Nephrostolithotomy: Is It All It’s Cracked up to Be?

by Wesley A. Mayer, MD | Oct 2019

Wesley A. Mayer, MD, discusses technological and procedural developments in mini percutaneous nephrostolithotomy (mPCNL) over the last 20 years. He describes the varied tools and methods of the procedure, outlines the lack of data on the efficacy of the procedure, and discusses the advantages and possible drawbacks of this method over standard PCNL.

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