Clinical Research Directory

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

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.

Trial to Assess the Efficacy of EMPAgliflozin and Personalized Dietary Counseling for Kidney STONE Prevention

The aim of this randomized trial with a 2-by-2 factorial design is to test the efficacy of the SGLT2 inhibitor empagliflozin and personalized dietary counseling based on 24-hr urine collection results and dietary assessments for kidney stone recurrence prevention in patients with calcium kidney stones. Study interventions: * Empagliflozin 10 mg once daily per os for 36 months * Personalized dietary counseling for 36 months. Control interventions: * Placebo once daily per os for 36 months * Generic dietary counseling for 36 months.

DISS vs FANS in Suction-Assisted RIRS for Medium-Sized Renal Stones

Kidney stones are a common health problem and may recur frequently, which can affect quality of life and kidney function. Retrograde intrarenal surgery (RIRS) is a minimally invasive treatment used for renal stones, but treatment of medium-sized stones may be associated with longer operative time, impaired visibility during surgery, residual stone fragments, and postoperative infectious complications caused by increased intrarenal pressure. Suction-assisted retrograde intrarenal surgery (RIRS) techniques have been developed to improve surgical efficiency and safety by facilitating continuous removal of stone fragments and helping control intrarenal pressure. Two commonly used suction-assisted approaches are direct in-scope suction (DISS) and flexible and navigable suction ureteric access sheath (FANS). However, there is limited prospective randomized evidence directly comparing these two techniques. This randomized prospective clinical study aims to compare direct in-scope suction (DISS) versus flexible and navigable suction ureteric access sheath (FANS) in adult patients with medium-sized renal stones measuring 1 to 2 cm who are undergoing retrograde intrarenal surgery (RIRS). Participants will be randomly assigned to one of the two suction-assisted techniques. The study will evaluate whether flexible and navigable suction ureteric access sheath (FANS) provides better outcomes than direct in-scope suction (DISS) in terms of stone-free rate and postoperative infection rate. The primary outcome is stone-free status assessed by postoperative imaging. Secondary outcomes include operative time, intraoperative visibility, and postoperative complications, particularly infection and urosepsis. The study hypothesis is that suction-assisted retrograde intrarenal surgery (RIRS) using the flexible and navigable suction ureteric access sheath (FANS) technique will result in a higher stone-free rate and a lower postoperative infection rate compared with direct in-scope suction (DISS) in the management of medium-sized renal stones.

FANS vs CVAC for Medium to Large Stones

Improvements in ureteroscopes have led to improved stone free rates. Two new devices (FANS - Flexible and Navigable Suction) and the CVAC ureteroscope have never been compared head to head. This trial will compare these two new suction ureteroscope technologies against each other

Observational Approach Versus Surgical Intervention for Stones

The aims of the Observational Approach versus Surgical Intervention for Asymptomatic Stone (OASIS) trial are: 1) to determine whether observation compared to upfront surgery results in less healthcare-related life disruption due to kidney stones among children and adults with asymptomatic kidney stones; 2) to identify the groups benefiting the most from each strategy; and 3) to determine the preferences and values informing the choice between observation and upfront surgery.

Intravesical Bupivacaine on Post-Operative Ureteroscopy Pain

Post-operative pain and lower urinary tract symptoms are common following ureteroscopy in the treatment of stone disease. The use of bupivacaine as a topical pain medication is used routinely for other urologic procedures, however, to date there are no studies that have rigorously investigated the effect of instilling bupivacaine in the bladder following ureteroscopy. This is a randomized study that will investigate the effect of instilling bupivacaine in the bladder following routine ureteroscopy, laser lithotripsy and ureteral stenting in the treatment of stone disease. Compared to a placebo of Normal Saline, our study hypothesizes that administration of topical bupivacaine in the bladder will decrease post-operative pain and lower urinary tract symptoms while improving quality of life in the early post-operative period.

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.

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

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

Empiric Versus Selective Prevention Strategies for Kidney Stone Disease

The aims of this study are to 1) Conduct a randomized clinical trial of selective versus empiric diet plus pharmacologic therapy in high-risk stone formers and 2) Determine adverse effects from, and adherence to selective and empiric strategies.

Outcomes and Inter-Stage Interval in Staged Bilateral PCNL

This prospective, single-center observational study evaluated patients undergoing staged bilateral standard percutaneous nephrolithotomy (PCNL) for bilateral renal stones. Each participant underwent PCNL on one kidney followed by contralateral PCNL in a separate session, allowing a paired within-patient comparison in which each patient served as their own control. The study aimed to compare operative, hematologic, renal, inflammatory, stone-free, and complication outcomes between the first and second PCNL procedures. In addition, the association between the inter-stage interval and second-side outcomes was explored, with particular emphasis on systemic inflammatory response assessed using neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), and systemic immune-inflammation index (SII).

Effect of a Low-Dose Ketamine-Dexmedetomidine-Based Opioid-Sparing Anesthesia Protocol on Postoperative Quality of Recovery After Percutaneous Nephrolithotomy

Percutaneous nephrolithotomy (PCNL) is a minimally invasive surgical procedure used to remove large or complex kidney stones. Although effective, dilation of the surgical tract and the placement of a nephrostomy tube cause significant postoperative pain. Conventional general anesthesia relies heavily on opioid medications (such as fentanyl) for pain control; however, opioids can cause unwanted side effects, including nausea, vomiting, dizziness, sedation, and delayed bowel recovery. The purpose of this clinical trial is to investigate whether an opioid-sparing general anesthesia protocol utilizing a combination of low-dose ketamine and dexmedetomidine improves overall postoperative quality of recovery in adult patients undergoing PCNL compared with standard opioid-based anesthesia. Participants will be randomly assigned to one of two groups: * Conventional Opioid-Based Group: Participants receive standard general anesthesia supplemented with intravenous fentanyl before induction and as needed during surgery to manage pain. * Ketamine-Dexmedetomidine Group: Participants receive general anesthesia combined with an initial dose and continuous low-dose intravenous infusion of ketamine and dexmedetomidine throughout the surgery. Following surgery, all participants will receive scheduled intravenous paracetamol, with rescue opioid pain medication (nalbuphine) available if pain levels reach a moderate-to-severe threshold. The primary outcome of the study is the patient-reported Quality of Recovery-15 (QoR-15) score at 24 hours after surgery. Secondary outcomes include total intraoperative and postoperative opioid consumption, postoperative pain scores at rest and during movement, time to first rescue pain medication, anesthesia emergence and recovery times, incidence of postoperative nausea and vomiting, and potential side effects.

Tissue Sensor for Semirigid Thulium Fiber Laser Ureterolithotripsy

Tissue Sensor (TS) is a technology designed to automatically deactivate laser emission when contact between the laser fiber and tissue is detected. It is hypothesized that the use of TS during contact laser ureterolithotripsy may reduce unintended laser exposure of the ureteral mucosa, thereby decreasing the risk of immediate thermal injury to the ureteral wall and subsequent scar-related narrowing. To reduce the influence of baseline risk factors for stricture, the study will enroll a homogeneous population of patients without urinary tract anomalies, previous surgery on the study ureter, or impacted stones. The procedure will be performed according to a standardized protocol using a semirigid ureteroscope, a thulium fiber laser, and predefined technical restrictions. The study is limited to patients with stones in the mid or distal ureter. This approach is intended to minimize the likelihood of stone retropulsion into the kidney, standardize the surgical technique, reduce the need for conversion to flexible ureteroscopy, and maximize comparability between the study groups.

Tract Closure in PCNL

This is a prospective, randomized controlled trial evaluating the effect of a hemostatic agent on tract-related bleeding during percutaneous nephrolithotomy (PCNL). Patients undergoing standardized PCNL will be randomized to receive either application of a hemostatic agent or no agent during tract closure, following uniform balloon occlusion, complete aspiration, and irrigation-free endoscopic assessment. The researchers hypothesize that adjunctive hemostatic agent use reduces perioperative hemoglobin decline compared with balloon tamponade alone and improves tract-related hemostasis outcomes.

A Randomized, Double-Blind, Placebo-Controlled Trial of Anrikefon for Postoperative Analgesia After Percutaneous Nephrolithotomy

This study evaluates whether a single dose of anrikefon, given intravenously shortly before the end of kidney stone removal surgery (PCNL), can reduce opioid-related side effects such as nausea, vomiting, itching, oversedation, and breathing problems in the first 24 hours after surgery. All participants receive the same standard pain control regimen (flurbiprofen axetil plus a sufentanil patient-controlled pump). In addition, half receive anrikefon and half receive a placebo (saline), decided by random allocation, with neither patients nor doctors knowing who receives which. A total of 160 adults (18-75 years) undergoing elective PCNL at Beijing Tsinghua Changgung Hospital will take part. Pain scores, opioid use, recovery, satisfaction, kidney function and side effects will be followed for up to 3 days after surgery.

6.3Fr Versus 7.5Fr Mini-Flexible Ureteroscopy for Renal Stones (MINI-FURS)

This prospective, randomized, single-blinded, non-inferiority clinical trial will compare the clinical outcomes and cost-effectiveness of two mini-flexible ureteroscopes (6.3Fr and 7.5Fr) used during flexible ureteroscopy for the treatment of renal stones. Adult patients with renal stones up to 15 mm who are scheduled to undergo flexible ureteroscopy will be randomly assigned to one of the two study groups. The primary objectives are to compare stone-free rates and the ability to achieve primary renal access without preoperative ureteral stenting. Secondary outcomes include operative time, fluoroscopy use, ureteral trauma, postoperative stenting, pain, complications, emergency department visits, need for additional procedures, hospital stay, and cost-effectiveness. The results of this study are expected to provide high-quality evidence to guide the selection of mini-flexible ureteroscopes and improve the quality, safety, and value of surgical care for patients with kidney stones.

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

Serum Endotoxin Assay to Predict the Development of Postoperative Infectious Complications and Systemic Inflammatory Response Following Percutaneous Nephrolithotomy.

The aim of the study is to establish an infectious risk stratification system based on pre-and post-operative blood endotoxin profile.

Tubeless vs Tube PCNL in Pediatric Nephrolithiasis

This study is designed to compare two surgical techniques for removing kidney stones in children and adolescents (ages 6-18 years). Both methods are types of percutaneous nephrolithotomy (PCNL), a standard procedure for kidney stones larger than 10 mm. In the traditional method, a temporary tube (nephrostomy tube) is left in the kidney after surgery to drain urine. In the newer "tubeless" method, the tube is not used, and only a small internal stent may be placed. We want to find out if the tubeless method is as safe and effective as the traditional method, and whether it reduces pain, hospital stay, and the need for blood transfusions. The study involves 640 patients at Khyber Teaching Hospital in Peshawar, Pakistan. Each participant is randomly assigned to one of the two techniques.

Comparing Efficiency and Stone-Free Rates Mini PCNL vs Flex URS

The objective of the study is to compare the stone free rates with ureteroscopy utilizing the ClearPETRA suction ureteral access sheath, and mini-PCNL; both procedures and ClearPETRA sheaths are standard of care and are used regularly for stone treatment. Our primary objective is to assess the complete stone free rate with both procedures.

Preoperative Anxiety in Patients Undergoing RIRS and PCNL

This prospective observational cohort study aimed to compare preoperative anxiety levels in adult patients undergoing retrograde intrarenal surgery (RIRS) or percutaneous nephrolithotomy (PCNL) for renal stones. The surgical approach was determined according to routine clinical indications and was not assigned by the study protocol. Preoperative anxiety was assessed using the State-Trait Anxiety Inventory-State (STAI-S) and the Amsterdam Preoperative Anxiety and Information Scale (APAIS). Demographic, clinical, and stone-related characteristics were also recorded to evaluate factors associated with preoperative anxiety.

Lanthanum Carbonate (Fosrenol®) to Reduce Oxalate Excretion in Patients With Secondary Hyperoxaluria and Nephrolithiasis

This study investigates the efficacy and the safety of Lanthanum Carbonate for the reduction of urinary oxalate excretion in patients with secondary hyperoxaluria and nephrolithiasis.

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.