Clinical Research Directory

Ureteral Access Strategies in Retrograde Intrarenal Surgery

Retrograde intrarenal surgery (RIRS) is a standard minimally invasive treatment for kidney stones up to 20 mm. During the procedure, irrigation fluid raises the pressure inside the kidney and laser energy raises the fluid temperature. High intrarenal pressure has been linked to postoperative pain, fever and infection. Ureteral access sheaths are used to improve fluid outflow, and newer flexible and navigable suction access sheaths (FANS) add active aspiration to keep pressure low and remove stone fragments. This randomized controlled trial compares three ureteral access strategies in adults undergoing RIRS: a flexible and navigable suction access sheath, a conventional ureteral access sheath, and no access sheath. The main question is whether the access strategy affects pain 6 hours after surgery. The study also compares intrarenal pressure and temperature during surgery, the amount of irrigation fluid used and retained, stone-free status on computed tomography (CT), and complications.

Comparison of Suction and Conventional Ureteral Access Sheaths in Kidney Stone Surgery

The goal of this observational study is to compare conventional and suction (aspiration) ureteral access sheaths used during retrograde intrarenal surgery (RIRS) in adults with kidney stones. The main questions it aims to answer are: * Does the use of a suction ureteral access sheath increase the stone-free rate compared with a conventional sheath? * Does the use of a suction sheath reduce operative time and complications such as postoperative fever and infection? Researchers will compare patients treated with a conventional ureteral access sheath with patients treated with a suction ureteral access sheath during routine RIRS. Participants will: * Undergo RIRS for kidney stones as part of their routine clinical care * Have their surgical data recorded, including operative time and any complications * Attend routine follow-up visits, including imaging to assess whether stones remain

IAU Percutaneous Nephrolithotripsy Study

During the past 10-15 years, important advancements have been witnessed in percutaneous nephrolithotomy (PCNL) techniques and instrumentation. The development of miniaturized PCNL techniques and modern laser technologies has contributed to lower complication rates, alongside changes in exiting strategies and postoperative drainage protocols. Ultrasound is increasingly utilized to create percutaneous access, and many medical centers have transitioned to the supine position for PCNL or perform Endoscopic Combined Intrarenal Surgery (ECIRS). All these developments have helped to individualize treatment strategies and to improve clinical outcomes for patients. However, there remains an ongoing discussion regarding the optimal indications and limitations of the different miniaturized PCNL techniques compared to standard PCNL and retrograde intrarenal surgery (RIRS). This prospective observational study is organized under the auspices of the International Alliance of Urolithiasis (IAU) and focuses on the contemporary indications, surgical techniques, instrumentation, exiting strategies, efficacy, and risk factors for intraoperative and postoperative complications of PCNL. Participating investigators will collect data on the PCNL procedures performed in their respective clinical centers prospectively for a period of 12-18 months. The study will be initiated in each clinical center following formal approval from the IAU Scientific Committee, which will also announce the conclusion of the study.

Tranexamic Acid to Improve Same-day Discharge Rates After Holmium Laser Enucleation of the Prostate (HoLEP)

This study is designed to assess if there is a significant difference in same day discharge rates after Holmium Laser Enucleation of the Prostate (HoLEP). The investigators attempt to perform HoLEP as a same-day discharge (SDD) procedure, but at Northwestern Memorial, the SDD rate is currently approximately 60%. The limiting factor in SDD is hematuria. Tranexamic acid (TXA) is a clot promoting drug that is commonly used by orthopedic, cardiac and obstetric surgeons to prevent bleeding. The primary outcome will be to assess if there is a difference in SDD rates in those who receive TXA vs. those who do not. Secondary outcomes will assess bleeding complications (defined as unplanned ED visit/clinic visit/procedure/admission related to bleeding, clot retention, clot evacuation, need for perioperative transfusion) between participants who receive TXA vs. those do not. The study will also assess differences in perioperative complications associated with TXA including but not limited to: deep venous thrombosis, pulmonary embolism, cerebrovascular events, between the groups. The study will also assess for the duration of postoperative hematuria between groups as well as differences in operative times between the groups. The investigators anticipate that there may be up to a 25% increase in SDD rates in those who receive TXA vs. those who do not.

Methocarbamol vs Oxybutynin for Management of Pain and Discomfort S/P Ureteroscopy Procedure

Stone disease is a common condition, affecting approximately 9% of Americans in 2007. It causes great morbidity and is also a costly condition, estimated to cost the US healthcare system approximately 3.79 billion dollars in 2007. Ureteroscopy (URS) is the most commonly performed surgical treatment for upper tract stone disease. Ureteral stenting is a common practice after ureteroscopy and placed in \~75% of cases to prevent ureteral edema and renal obstruction. Unfortunately, ureteral stenting can be very painful and has been shown to increase the rate of emergency room visits. Many strategies have been attempted to decrease pain with ureteral stenting including modification of stent material and designs, but efforts so far have been unsuccessful in decreasing stent-related morbidity. Stent-related morbidity is hypothesized to be secondary to irritation of ureteral/bladder mucosa and muscle. Analgesics such as alpha blockers and NSAIDs have been shown to reduce stent morbidity. Anticholinergic drugs are also utilized as they decrease bladder spasms and, therefore, are hypothesized to reduce stent irritation. However, the evidence for anticholinergics has been conflicting. Anticholinergics also have a serious side effect profile including dry mouth, dry eyes, constipation, urinary retention, blurred vision, and even dementia. Some authors even hypothesize that these side effects may offset any purported benefits the anticholinergics provide for stent-morbidity. Methocarbamol is anti-spasmodic muscle relaxant that is believed to work by acting on central neurons and possibly by blocking sodium channels. Given that anticholinergics have many side effects and questionable efficacy, the investigators hypothesize that methocarbamol may achieve superior analgesia for stent morbidity and stent-related bladder spasms. Oxybutynin is used for the treatment of overactive bladder. The rationale is that the oxybutynin relaxes the muscles in the bladder to help decrease problems of urgency and frequent urination caused by the urinary stent irritation. Since anticholinergics have multiple side effects, finding an equally efficacious alternative with less side effects is highly desirable. This study will evaluate the clinical and demographic factors of patients undergoing ureteroscopy and treated postoperatively with methocarbamol vs. oxybutynin for stent-related morbidity. Additionally, the study will aim to understand the postoperative outcomes and complication rates of patients discharged with methocarbamol vs. oxybutynin after ureteroscopy with a ureteral stent in place.

Gut Oxalate Absorption in Calcium Oxalate Stone Disease

The goal of this clinical trial study is to test if patients with idiopathic calcium oxalate kidney stones have an increased absorption of dietary oxalate, which would lead to increased urinary excretion of oxalate. The study will recruit adult patients with a history of calcium oxalate kidney stones and healthy volunteers without kidney stones. Participants will * ingest fixed diets containing low and moderately high amounts of oxalate for 5 days at a time * ingest a soluble form of oxalate and sugar preparations to test gut permeability * collect urine, blood, stool and breath sample during the fixed diets and the soluble oxalate test

O. Formigenes Colonization in Calcium Oxalate Kidney Stone Disease

The goal of this trial is to test if colonization with the gut bacteria Oxalobacter formigenes leads to a reduction in urinary oxalate excretion in patients with calcium oxalate kidney stone disease. The study will recruit adult participants with a history of calcium oxalate kidney stones who are not colonized with Oxalobacter formigenes. Participants will * ingest fixed diets containing low and moderately high amounts of oxalate for 4 days at a time * collect urine, blood and stool samples during the fixed diets * ingest a preparation of live Oxalobacter formigenes to induce colonization with Oxalobacter formigenes

Human Voice vs AI-Cloned Voice Audio Added to Written Consent Before Ureteroscopy or Retrograde Intrarenal Surgery (AUDIO-CONSENT)

Before kidney stone surgery with a flexible or semirigid ureteroscope, patients must read and sign a written consent form, but many patients find these forms long and hard to understand. This study tests whether listening to an audio recording of the same consent form, in addition to the usual written form and the surgeon's explanation, helps patients understand the operation better. It also asks whether it matters if the recording is read by a real urologist or produced by artificial intelligence (AI) from a clone of that same urologist's voice. Adults scheduled for their first ureteroscopy or retrograde intrarenal surgery at three hospitals in Turkey will be randomly assigned to one of three groups: (A) standard written consent only, (B) standard consent plus an audio recording read by a urologist, or (C) standard consent plus the same text produced by an AI-cloned version of the same urologist's voice. All three groups receive exactly the same information, word for word; only the way it is delivered differs. Patients in group C are told that the voice was produced by AI. The main outcome is a 10-question knowledge test on the content of the consent form, taken immediately after the consent process. Anxiety (State-Trait Anxiety Inventory) and satisfaction are also measured on the same day. No forms are completed on the day of surgery.

Nephrostomy Tract Infiltration for Pain Control After PCNL

This prospective, randomized, controlled clinical trial aims to evaluate the effectiveness of nephrostomy tract local anesthetic infiltration for postoperative pain control in patients undergoing prone percutaneous nephrolithotomy. Eligible patients will be randomly assigned to either a control group receiving standard systemic postoperative analgesia or an intervention group receiving standard analgesia plus infiltration of 20 mL of 0.25% bupivacaine along the nephrostomy tract at the end of surgery. Postoperative pain will be assessed using the Visual Analog Scale at 1, 6, 12, and 24 hours. Secondary outcomes will include time to first analgesic requirement, total opioid consumption during the first 24 hours, need for rescue analgesia, time to mobilization, length of hospital stay, and treatment-related complications. The study is designed to determine whether nephrostomy tract infiltration provides a simple, safe, and effective adjunct for reducing pain and analgesic consumption after percutaneous nephrolithotomy.

Ambulatory Versus Inpatient Percutaneous Nephrolithotomy

The goal of the study is to determine if ambulatory tubeless PCNL is safe and effective compared to inpatient PCNL with a nephrostomy tube.

Endogenous Oxalate Synthesis in Idiopathic Calcium Oxalate Kidney Stone Disease

The goal of this clinical trial study is to test if patients with idiopathic calcium oxalate kidney stones have an increased production of oxalate by the body, which would lead to increased urinary excretion of oxalate. The study will recruit adult patients with a history of calcium oxalate kidney stones and healthy volunteers without kidney stones. Participants will ingest fixed diets containing low amounts of oxalate for 5 days ingest a soluble form of glycolate and vitamin C collect urine, blood, stool during the dietary and oral dosing portions of the study and also collect breath sample during the oral glycolate test

Flexible Ureteroscopy for Large Renal Stones in Children

This prospective single-arm interventional study evaluated the efficacy and safety of flexible ureteroscopy for the treatment of large renal stones measuring 2 cm or more in pediatric patients. All enrolled participants underwent flexible ureteroscopic stone disintegration using a single-use flexible ureteroscope and Holmium laser lithotripsy. The study was designed to assess whether this minimally invasive approach could provide effective stone clearance with acceptable perioperative safety in children with large renal stones.

Safety and Efficacy of Fluoroscopy-free Technique During Retrograde Intrarenal Surgery for Renal Stones

Aiming to reduce radiation exposure to patients and physicians, the investigators conduct this study protocol to evaluate the possibility of performing retrograde intrarenal surgery (RIRS) under direct visualization without fluoroscopy. the investigators will prospectively evaluate the outcome of fluoroscopy-free RIRS for renal stones in comparison with the standard technique. The investigators expected that the fluoroscopy-free technique has high safety and efficacy even in complicated cases.

Effect of Anesthesia Type on Surgeon Workload During Endoscopic Kidney Stone Surgery

This prospective observational study aims to evaluate the association between anesthesia type and surgeon-perceived workload and surgical ergonomics in adult patients undergoing flexible ureteroscopy and retrograde intrarenal surgery (RIRS) for kidney stones. Patients will be classified according to the anesthesia administered during routine clinical care as general anesthesia or spinal anesthesia. The choice of anesthesia will be determined by routine clinical practice and the anesthesiology team and will not be assigned by the study protocol. Surgeon workload will be assessed immediately after surgery using the Surgery Task Load Index (SURG-TLX). Perioperative outcomes, including operative time, procedural characteristics, postoperative pain, complications, and stone-free status, will also be evaluated.

Nebulized Glubran 2-Assisted Tubeless PCNL Versus Conventional PCNL

This prospective randomized controlled study will compare two techniques used after percutaneous nephrolithotomy, a procedure for removing kidney stones. Participants with renal stones measuring 2-3 cm will be randomly assigned to either tubeless percutaneous nephrolithotomy with nebulized Glubran 2 used to seal the access tract or conventional percutaneous nephrolithotomy with placement of a nephrostomy tube. The study will evaluate whether the Glubran 2-assisted tubeless technique is safe and effective and whether it can reduce postoperative pain, bleeding, hospital stay, urine leakage, and other complications while maintaining a satisfactory stone-free rate.

Comparison of Vacuum-Assisted and Conventional Ureteral Access Sheath in Retrograde Intrarenal Surgery

This study aims to compare the efficacy and safety, the ratio of stone-free rates, and complications of two types of access sheaths used in retrograde intrarenal surgery to treat upper urothelial stones. The access sheath types are those with vacuum aspiration and the conventional ones.

Access Sheaths With Aspiration for Renal RetrOgrade Surgery, Randomized CompArative Outcomes

The goal of this clinical trial is to learn whether the ClearPetra ureteral access sheath (Coloplast) is more effective than the Navigator ureteral access sheath (Boston Scientific) in treating intrarenal kidney stones of 1-3 cm in adult patients undergoing flexible ureteroscopy (RIRS). The main questions it aims to answer are: Does ClearPetra achieve a higher stone-free rate at 1 month post-intervention compared to Navigator, as assessed by non-contrast abdominal-pelvic CT scan? Does ClearPetra reduce total surgical time compared to Navigator? Does ClearPetra lower the retreatment rate at 3 months compared to Navigator? Does ClearPetra present a rate of clinically significant complications (Clavien-Dindo ≥ II) that is lower than or similar to Navigator? Researchers will compare flexible ureteroscopy using the ClearPetra vacuum-assisted flexible ureteral access sheath to flexible ureteroscopy using the Navigator standard rigid ureteral access sheath, to see if ClearPetra leads to higher stone clearance rates while maintaining a comparable safety profile. Participants will: Undergo flexible ureteroscopy (RIRS) using one of two randomly assigned ureteral access sheaths (ClearPetra or Navigator), determined by computer-generated randomization immediately before surgery Have a non-contrast abdominal-pelvic CT scan at 1 month post-intervention to assess stone-free status Have a non-contrast abdominal-pelvic CT scan at 3 months post-intervention to evaluate residual fragments and the need for retreatment Attend follow-up visits at 1 month and 3 months post-surgery for clinical assessment and complication recording The study will be conducted at the Urology Department of Hospital Universitario Virgen del Rocío (Seville, Spain), a tertiary reference centre. A total of 156 patients will be randomized in a 1:1 ratio (78 per group), with pre-defined subgroup analyses stratified by stone size (1-2 cm vs. \>2 cm). The outcome assessor evaluating CT images for stone-free rate will be blinded to treatment allocation (single-blind).

Suction Mini-PCNL Versus Standard PCNL for the Management of 2-4cm Kidney Stones

Percutaneous nephrolithotomy (PCNL) is recommended as the first-line treatment choice for kidney stones larger than 2cm in international guidelines . However, tract-related complications affecting renal parenchymal and blood vessels have always been a concern . The mini-PCNL technique which uses a smaller tract (≤18 Fr) has been introduced to decrease tract-related complications . Nevertheless, the smaller mini-PCNL tract necessitates fragmentationi of stones into smaller pieces before extraction, potentially prolonging the operative time. Additionally, higher pressure irrigation is often required to flush out fragments by vacuum cleaner effect. If the drainage of irrigation fluid is insufficient via a smaller tract, the intrarenal pressure (IRP) may build up, leading to pyelovenous backflow and infectious complications. Suction application in mini-PCNL has the potential to enhance stone fragments removal efficiency, maintain low IRP, and decrease potential postoperative infection complications. In the pre-suction era, mini-PCNL achieved noninferior stone-free rates (SFR) and operative times compared to standard PCNL, along with benefits of reduced bleeding, less postoperative pain, and shorter hospital stay. However, high-level evidence regarding whether suction mini-PCNL can attain comparable outcomes to standard PCNL is still lacking. Therefore, we have designed this multicenter, international, randomized controlled noninferiority trial comparing suction mini-PCNL with standard PCNL in the management of 2-4 cm kidney stones.

Antibiotic Irrigation and Suction Ureteral Access Sheath in RIRS

Retrograde intrarenal surgery (RIRS) is a widely used treatment for kidney stones; however, postoperative infectious complications remain a significant concern. This prospective randomized factorial trial aims to evaluate whether gentamicin-containing irrigation fluid and the use of a suction ureteral access sheath can reduce postoperative fever, systemic inflammatory response syndrome (SIRS), and sepsis after RIRS. The study will also investigate the independent and combined effects of these two interventions on infectious outcomes.

Supine vs. Prone PCNL for Large Renal Stones: A Randomized Trial in Yemen.

The goal of this clinical trial is to compare the safety, cost-effectiveness, and patient recovery of two different surgical positions for percutaneous nephrolithotomy (PCNL) in adults aged 18 to 70 years who have kidney stones larger than 2 cm. The main questions it aims to answer are: * Does the supine (lying on the back) surgical position result in fewer early postoperative complications than the traditional prone (lying on the stomach) position? * Does the supine position reduce the total surgery time, direct hospital costs, and postoperative pain? Researchers will compare patients assigned to undergo PCNL in the supine position to those assigned to the prone position to see if the supine approach offers a safer, more cost-effective, and more comfortable recovery. Participants will: * Undergo standard PCNL surgery to remove their kidney stones in either the supine or prone position. * Have their pain levels, surgery time, and any early surgical complications monitored during their hospital stay. * Complete brief questionnaires regarding their overall surgical satisfaction and quality of life at 1 month and 3 months after the procedure.

Ureteral Stent Placement After Ureteroscopy for Renal Stones: A Randomized Controlled Trial

The rationale for this study is to determine if there is a difference in complications among patients undergoing ureteroscopy for renal stones who receive a stent compared to not receiving a stent postoperatively.

SOUND Pivotal Trial - (Sonomotion stOne comminUtion resoNance ultrasounD)

The goal of this clinical trial is to test the Break Wave™ system in patients with upper urinary tract stones. The main question it aims to answer is whether the device is safe and effective in fragmenting (breaking) stones. Participants will a) undergo the Break Wave™ procedure, b) have a telehealth visit at 2 weeks, and c) return for an imaging study at approximately 10 weeks post-procedure.

An International Multicenter Clinical Study on Application of UroMed AI Doctor Based on Large Language Models

This study evaluates our team's urology-specific AI (UroMed AI Doctor) for its safety, professionalism, knowledge and Q\&A ability, and tests its effectiveness against traditional manual urology care, to confirm if it can be a safe auxiliary tool and improve patients' preoperative experience. Before the study, we will test the AI with urology questions, compare it to international AI models (DeepSeek, ChatGPT, Google Gemini), and have two senior chief physicians evaluate it. In the clinical trial, patients at The First Affiliated Hospital of Guangxi Medical University will be randomly split into two groups: AI-assisted care or traditional care by a specialist. Two senior specialists will evaluate both groups blindly; each group will get preoperative education (AI or physician), with anxiety and satisfaction surveyed. Subsequently, a multi-center validation will be conducted with 11 domestic and international hospitals.

Metaphylaxis of Infected Kidney Stones After Percutaneous Nephrolithotripsy

Kidney stone recurrence, particularly infection-related stones, remains a significant clinical problem after percutaneous nephrolithotripsy (PCNL). Bacterial colonization and persistent infection are recognized contributors to stone recurrence. This study evaluates the effectiveness of intrarenal dioxidine instillation as a metaphylactic measure to reduce recurrence of infection-related kidney stones following PCNL. Patients undergoing PCNL will receive standard treatment, with or without adjunctive intrarenal dioxidine administration. The study aims to assess whether this approach reduces stone recurrence and infection-related complications.