Can Ureteral Wall Thickness Help Predict Stone Passage?

We investigated whether measuring ureteral wall thickness (UWT) could help predict if kidney stones would pass naturally, without requiring surgery. In a study of 199 patients with ureteral stones, researchers analyzed various stone characteristics and UWT using CT scans. While initial analysis suggested thicker ureter walls were associated with lower chances of spontaneous stone passage, this factor became insignificant when accounting for other variables. The study concluded that stone size remains the most reliable predictor of whether a stone will pass naturally.

Determining the Natural Distensibility of the Human Ureter

We examined how much the human ureter (the tube connecting kidney to bladder) can naturally stretch and what factors affect its flexibility. We tested 101 patients during kidney stone procedures, using specially monitored tools to measure safe stretching limits. Our findings showed that most ureters could safely accommodate up to 14F-sized instruments, while 39% could handle larger 16F sizes. Having a pre-existing ureteral stent or recent antibiotic use significantly increased the likelihood of accepting larger instruments, while other factors like certain medications showed no effect.

Developing a Cost-Effective Force Sensor for Ureteroscopy

We developed and validated a simple, affordable method to monitor insertion forces during kidney stone surgery using a standard 1.0 mL syringe, as an alternative to expensive force sensors. By measuring specific compression points of the syringe, surgeons can reliably identify safe force thresholds, helping prevent ureteral injury during procedures.

Using a Novel Robot-Assisted Platform to Combine Two Minimally Invasive Urologic Surgeries

We evaluated a novel robotic system (MONARCH Platform) that allows a single surgeon to perform combined minimally invasive kidney stone procedures. In a first-in-human trial of 13 patients with large kidney stones, the robotic system successfully completed 12 procedures, achieving precise kidney access and removing 98.7% of stone volume on average. With only minor complications reported and good stone clearance rates, this preliminary study demonstrates that robotic-assisted kidney stone surgery is both safe and effective.

Can Small Renal Mass Biopsies Help Prevent Unnecessary Kidney Surgeries?

Current guidelines don’t require a biopsy before surgery for small kidney tumors, leading to unnecessary kidney removal in up to 26% of cases. This review challenges the reasons for skipping biopsies and highlights that renal mass biopsy (RMB) is just as accurate and safe as biopsies for other cancers like breast or lung. Given its reliability, we suggest that kidney surgery should only proceed after a biopsy confirms cancer. They propose updating medical guidelines to make RMB a routine step before removing small kidney tumors.

Too Much Force?

We aimed to understand the force urologists and residents use when inserting ureteral access sheaths (UAS), given that excessive force can cause ureteral injury. At two major urology conferences, we recruited 121 participants to test their force application on a genitourinary model with a concealed force sensor. Our findings revealed that most urologists exceeded the optimal force range of 4N to 6N, with nearly half surpassing 6N and a third exceeding 8N. Surprisingly, more experienced urologists were more likely to use excessive force. These results highlight the need for better training and awareness to minimize ureteral injury risk during UAS placement.

Does Alkaline Water Live Up to the Hype?

We investigated whether commercially available alkaline water could effectively increase urinary pH for patients with uric acid and cystine kidney stones. By analyzing five popular brands, we found that while their pH ranged from 9.69 to 10.15, their actual alkali content was negligible—far lower than potassium citrate, the gold standard for urinary alkalinization. In fact, several other beverages and supplements contained significantly more alkali than alkaline water. These findings suggest that alkaline water offers no real benefit over tap water for managing urinary pH in stone-forming patients.

Using AI to Measure Kidney Stones

We tested an AI program from the University of California, Irvine, to measure kidney stone size more accurately than current methods. Using 322 CT scans, we found that the AI’s volume measurements were almost identical to a trusted 3D measurement method. In contrast, traditional formulas often overestimated stone size, and simple length measurements were the least accurate. The AI was especially reliable for larger stones and closely matched the true shape and size. Making this tool widely available could help doctors better plan treatments for kidney stone patients.

A New Way to Deliver Drugs

We tested a technique called Electromotive Drug Administration (EMDA) to see if it could improve drug absorption in the kidney’s inner lining. Using a pig model, we delivered a blue dye (methylene blue) into both kidney pelvises, applying a mild electrical current to one side. The treated side showed deeper and more even dye absorption compared to the untreated side. Microscopic analysis confirmed that the dye penetrated deeper into the tissue. This suggests that EMDA could enhance drug delivery for kidney treatments.

An Evaluation of Resonance Metal Stents

We evaluated long-term use of metal-based Resonance stents (RS) in patients with benign ureteral obstruction (BUO). Over 26 months, kidney function remained stable, with RS lasting an average of 9.7 months. While 26% required early replacement and 32% had encrustation, RS placement was a cost-effective alternative to polymeric stents. Our findings suggest RS can effectively manage BUO while preserving kidney health.

Testing a New Drug Delivery Method

We tested electromotive drug administration (EMDA) for delivering methylene blue into the ureter for the first time. In four porcine ureters, an EMDA catheter with a silver wire was used to infuse the dye, with two ureters receiving a pulsed current while the other two served as controls. After 20 minutes, the ureters were examined. The EMDA-treated ureters showed widespread staining, with methylene blue penetrating deeper into the tissue, reaching the lamina propria and muscularis propria, while the control ureters only showed limited staining. This study demonstrates that EMDA can successfully deliver drugs deeper into the ureteral tissues.

Comparing the Effectiveness of Different Ablation Lasers

We compared the effectiveness of the superpulse thulium fiber laser (sTFL) and the holmium: yttrium-aluminum-garnet (Ho:YAG) laser for breaking down renal stones in a porcine model. The results showed that sTFL required significantly less time to break down stones and used less energy. sTFL also had a higher stone clearance rate and produced smaller fragments compared to Ho:YAG treatment. These findings suggest that sTFL is more efficient and effective for stone dusting.

Prosthetic Bladder

We tested a new material, bilayer silk fibroin scaffold (BLSF), to create a synthetic bladder replacement in pigs. After removing the bladder, the BLSF was used to connect the prosthetic bladder to the ureter and urethra. Tissue analysis showed that the synthetic bladder successfully connected with the natural tissue, showing promise for using BLSF in bladder replacements.

Comparing Dual-Lumen vs. Single-Lumen Ureteroscopes

We compared the performance of single-lumen (SLFU) and dual-lumen (DLFU) flexible ureteroscopes in managing upper urinary tract stones. We found that patients treated with the DLFUs had shorter laser lithotripsy times, better stone clearance rates, and a higher stone-free rate compared to the SLFUs. However, both groups had similar ureteroscopy times, basketing times, and complication rates. Surgeons rated the DLFU significantly better in terms of visibility, comfort, ease of use, and overall performance.

Testing a New Treatment for Kidney Stones

We treated three high-risk female patients with large or smaller kidney stones using a new 16F flexible cystoscope with dual aspiration and irrigation for retrograde cystonephroscopy. The patients had an average preoperative stone volume of 4950 mm³, but after the procedure, their stones were reduced to an average of 217 mm³, and we achieved a 97% stone clearance rate. The procedure took an average of 176 minutes, and no major complications occurred. This approach was effective for safely treating large-volume kidney stones in high-risk patients without the need for more invasive procedures.

Pre-Stenting Increases Ureteral Size

We assessed the impact of 1 week of ureteral stenting on the maximum safe dilation of ureteral luminal circumference in juvenile female pigs. After stenting, most ureters showed an increase in luminal circumference, with a significant number dilated to larger sizes. Importantly, no high-grade ureteral injuries were observed. These findings suggest that stenting for 1 week can safely increase ureteral luminal circumference, potentially improving the outcomes of stone removal procedures.

Improving Stone Clearance

In an ex vivo study, we evaluated three laser types (Ho:YAG, Ho:YAG-MOSES, and superpulse thulium fiber laser [sTFL]) for their effectiveness in stone dusting. The study found that sTFL combined with suction and a 14F ureteral access sheath (UAS) resulted in the highest stone clearance, at 94%, compared to Ho:YAG, which cleared 65% of stones. Aspiration improved stone clearance only with sTFL, as it created smaller fragments. The presence of a 14F UAS improved stone clearance across all laser modalities. This combination of sTFL, suction, and UAS optimized stone clearance.

Assessing the Surgical Skills of Urology Resident Applicants

This study evaluated whether surgical skills testing through crowdsourcing could reliably assess urology residency applicants and whether these skills impacted their match rank. Applicants completed tasks such as open knot tying, laparoscopic peg transfer, and robotic suturing, with performance evaluated by both experts and crowd-workers. We found that surgical skills scores did not correlate with match rank, USMLE scores, or empathy scores. However, interview scores and faculty evaluations of laparoscopic skills were significant predictors of match success.

Global Assessments of the Endockscope System

This study evaluated a $45 alternative endoscope, the Endockscope System (ES), made from 3D-printed attachments, a lens, and an LED flashlight. It was distributed to 40 urologists from 23 countries at international conferences. A survey conducted in 2020 showed high satisfaction and many found it equal or superior in quality to standard equipment. The ES proved to be a cost-effective tool, expanding endoscopy access in resource-limited settings.

Temperature Risks of Laser Procedures

We studied how the thulium fiber laser (TFL) affects kidney temperatures during stone removal, focusing on how laser settings, ureteroscope type, and irrigation temperature impact these temperatures. In our pig model, we found that without a ureteral access sheath (UAS), temperatures often exceeded safe levels, potentially causing tissue damage. However, using a UAS helped control the temperature. We also found that the temperature readings at the ureteroscope tip didn’t always reflect the actual temperature inside the kidney. Our results suggest TFL is a promising tool for stone removal but requires precautions to avoid overheating kidney tissue.

Impacts of Renal Mass Biopsies

We investigated the impact of routine renal mass biopsy (RMB) before surgery in patients with small kidney tumors compared to patients who went directly to treatment. Our study found that the RMB group had a significantly lower rate of unnecessary surgery for benign tumors and a higher rate of active surveillance for tumors with benign results. Biopsy results were highly accurate in determining whether a tumor was benign or malignant, and there were no complications from the procedure. Overall, our findings suggest that routine RMB for small renal masses can help reduce unnecessary surgeries and allow for more careful monitoring of benign tumors.

Office-Based Renal Tumor Biopsy: a Paradigm Change in the Management of a Small Renal Mass?

We evaluated the use of office-based renal mass biopsy (RMB), which could change how we approach treating kidney tumors. RMB is underused compared to biopsies for other types of tumors, and most are done by radiologists. However, ultrasound-guided office-based RMB is safe, reliable, and influences treatment decisions. The practice of urologists performing these biopsies in-office is growing, and it’s proving to be effective with minimal risk or discomfort for patients.

How Much Force is too Much?

We conducted a study to identify the safe amount of force for deploying a ureteral access sheath, a common procedure that can sometimes cause injury to the ureter. Using a force sensor, we measured the forces applied during sheath insertion. We found that when the force exceeded a certain threshold, the risk of ureteral injury increased. Our results suggest that limiting the insertion force is key to avoiding injury, and certain factors, like previous stone surgery or medication, can help make the procedure easier.

Kidney Stones and Quality of Life

We investigated how chronic kidney stone recurrence affects a person’s quality of life by using a validated survey tool, the Wisconsin Stone Quality of Life (WISQOL) questionnaire. Our analysis showed that the more stone events someone experienced, such as pain episodes or treatments, the lower their quality of life. Specifically, quality of life declined significantly after more than five stone events. These results highlight the importance of identifying and addressing the underlying causes of frequent stone recurrence to improve patient well-being.

Irrigant Fluid Temperature

We aimed to examine how warming irrigation fluid to just below the injury threshold affects ureteral peristalsis (the movement of the ureter) and the ureter’s diameter during ureteroscopy. In a pilot study with two pigs, we tested fluid at 37°C and 43°C. We found that warming the fluid did not significantly change the ureter’s size or make it easier to insert a ureteral access sheath. Both temperatures increased peristalsis slightly, but there was no significant difference in force needed for sheath placement. Our results suggest that warming irrigation fluid to body temperature remains optimal for ureteroscopy.

Using Virtual Reality for Surgical Planning

We conducted a study to assess how interactive virtual reality (iVR) models of kidney anatomy could improve surgical outcomes and patient understanding for living donor nephrectomy (LDN). Surgeons and patients were able to view and interact with 3D models of the donor’s kidney, created from CT scans. Some surgeons reported altering their preoperative plan after using iVR, and patients felt they had a better understanding of their anatomy and experienced less anxiety. Compared to patients who didn’t use iVR, the iVR group had a significant reduction in surgical time and better kidney function recovery post-surgery. Overall, iVR improved both surgical planning and patient outcomes.

Reducing the Dose of CT Radiation

We evaluated a new triple bolus computerized tomography (CT) protocol to reduce radiation exposure while diagnosing hematuria, compared to the conventional CT method. The triple bolus CT uses fewer scans and exposed patients to 33% less radiation than the conventional method. Despite this reduction in radiation, both protocols detected urological issues (like stones, cysts, and masses) at similar rates. This study shows that the triple bolus CT is just as effective as the conventional method in detecting urological problems but with much lower radiation exposure, making it a safer option for evaluating hematuria.

Innovative Force Sensor

A ureteral access sheath is like a protective tube for your ureter. Urologists insert these “tubes” into your ureter to allow safe passage of surgical tools and to maintain access to your kidneys and kidney stones. Our team developed and tested an innovative force-sensing device to study the maximum amount of force any urologist should use (8 Newtons) to avoid ureteral injury or tearing.

Alkaline Water: Help or Hype for Uric Acid and Cystine Urolithiasis?

Innovative Force Sensor

A ureteral access sheath is like a protective tube for your ureter. Urologists insert these “tubes” into your ureter to allow safe passage of surgical tools and to maintain access to your kidneys and kidney stones. Our team developed and tested an innovative force-sensing device to study the maximum amount of force any urologist should use (8 Newtons) to avoid ureteral injury or tearing.

Procedure: Automated vs. Manual

Urologists have an optimal view of your kidney stones through a ureteroscope, if water irrigation or flow and pressure is maintained. Imagine if during your procedure, your urologist’s eyes were relying on your circulating nurse to manually pump or push water through a small straw while maintaining constant pressure and flow. We sought to compare the newest automated irrigation pump technology on the market to the traditional hand pump. We found that with an automated pump, workflow time reduced in the operating room and nurse satisfaction increased.

First to Map Out Kidney Blood Flow Using innovative Doppler Ultrasonography

In a porcine model, a miniaturized Doppler ultrasound probe used during ureteroscopy demonstrated that the renal papilla had the least amount of blood flow, whereas the infundibula had the highest blood flow. This data may serve to inform site selection during percutaneous nephrostomy needle placement.

Laser From the Inside Out

Percutaneous nephrolithotomy (PCNL) remains a challenging procedure, primarily due to surgical difficulties when obtaining access to the kidneys, by puncturing a needle from a patient’s back to the kidney. Few urologists obtain their own access even under fluoroscopic or ultrasonic guidance. We are the first to report and successfully perform the use of holmium laser energy under endoscopic guidance to obtain access from the inside out. The accuracy of nephrostomy tube placement and lessening of fluoroscopy time are two potential benefits of this approach.

Enlarging the Kidney’s Collecting System for Procedural Planning

Non-contrast CT scans are commonly used when planning how to procedurally approach your kidney stone. Our team sought to evaluate an innovative DRINK protocol including oral hydration and diuretic, to enlarge the kidney’s collecting system prior to this scan. The DRINK protocol significantly increased the visible collecting system volume and surface area. In the majority of cases, the width of the inside and outside of the kidney was expanded.

Relaxed Ureter = Large Diameter Access Sheath

Remember the small straw analogy? We sought to find a medical expulsive therapy which would maximize the relaxation of your ureter prior to ureteral access insertion. We found that with the use of oral Tamsulosin (i.e., medical impulsive therapy), there was an increase in cases where large access sheath was achieved without the use of a pre-operative ureteral stent placement.

Gravity Works

When using a laser to break up kidney stones, fragments can flow back up into your kidney. We found that increasing the angle you position the operating room bed can effectively prevent this from occurring. In other words: Gravity Works!

Laying Down or Facing Up?

Percutaneous nephrolithotomy (PCNL) is used for large and complex renal stones. Because it’s a challenging procedure, its technique, equipment, and even patient positioning have undergone adjustments over time. Prone position (patient lying face-down) is most widely used, but the supine position (patient lying face-up) has been introduced, bringing the optimal position into debate. Our team looked at published data and determined that neither approach is significantly superior to the other. Rather, modern-day PCNL techniques have made it possible for either position to be used.

Pellethane®: A Material That Resists Encrustation

Encrustation of implanted urinary tract devices is associated with significant illness. Pellethane® is a polyether-based material that is strong, porous and resistant to solvents. We assessed Pellethane® with and without surface coatings for the potential to resist encrustation in an artificial urine environment. Pellethane®, particularly with a HEMA-based preventative coating, may serve as a favorable alternative to traditional urinary stent material, providing its improved resistance to encrustation.

Smartphone Technology

Smartphone technology has propelled the evolution of health-related mobile technology, referred to as mobile health (mHealth). With the rise of smartphone ownership and the growing popularity of health-related smartphone usage, mHealth offers potential benefits for both patients and healthcare providers. Our team reviewed publications focused on the use of smartphones in urology to evaluate any benefit of smartphone technology over standard of care. We found that while smartphone technology is constantly evolving and has the potential to improve urological care and education, of concern to consumer and urologist alike is that these downloadable programs are limited due to the accuracy of their content, risk of confidentiality breach, and the lack of central regulation and professional involvement in their development.

Endockscope

The Endockscope system (ES) combines a smartphone, lens system, and a rechargeable LED light source to provide a low-cost alternative ($45) to the standard camera and high-powered light source ($45,000) used in traditional endoscopic procedures. Our team assessed the performance and diagnostic capability of the ES system vs. the standard endoscopic system using four rigid/semi-rigid endoscopes. We found that he ES plus the Apple iPhone X or Samsung Galaxy S9+ offers comparable imaging and provides diagnostic information equivalent to the standard system for rigid endoscopy of the kidney, ureter, and bladder; the Galaxy S9+ provides comparable imaging and diagnostic capabilities for evaluation of the abdomen.

Endockscope II

The Endockscope system (ES) combines a smartphone, LED light source, and fiberoptic cystoscope for mobile videocystocopy. Our team compared the conventional method of videocystocopy with the Endockscope (used with next generation smarthpones) to evaluate image quality/resolution, brightness, color quality, sharpness, and acceptability for diagnostic use. When coupled with an Apple iPhone 7 or Samsung Galaxy S8, the Endockscope system ($45) was comparable to conventional videocystoscopy ($45,000).

Virtual Reality

Percutaneous nephrolithotomy (PCNL) requires the urologist to have detailed knowledge of the stone and its relationship with the renal anatomy. Our team looked at how immersive virtual reality (iVR) can benefit both surgeons and patients when compared to CT alone. We found that iVR improved urologists’ understanding of renal anatomy and altered the preoperative approach in 40% of cases. It also contributed to decreased fluoroscopy time and less blood loss. For patients, iVR reduced preoperative anxiety and improved their understanding of stone disease.

Flow Rates

Our team evaluated the flow characteristics of manual and automated-pump irrigation systems connected to a flexible ureteroscope. The flow rates of irrigation produced by both types of pump were similar at pressures of 150 and 200 mm Hg, regardless of the occupancy of a ureteroscope’s working channel during the first 5 minutes of irrigation. The pressure at the entry site of the ureteroscopy is subject to significant variability with use of the manual pump when compared to the automated pump.

Drink Coconut Water

Coconut water has long been publicized for its medicinal qualities, including natural hydration. We sought to determine if consumption would change factors affecting the formation of kidney stones. We found that coconut water consumption increases urinary potassium, chloride, and citrate without altering urine pH.