Clinical Research Directory

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 2 to 3 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

Erector Spinae Plane Block for Percutaneous Nephrolithotomy

Percutaneous nephrolithotomy (PCNL) is an effective standard urological procedure for the fragmentation and removal of large renal calculi. Although PCNL is performed as a minimally invasive technique, dilation of the renal capsule and parenchymal tract, as well as peritubular distension caused by the nephrostomy tube, may result in severe postoperative pain. Various analgesic strategies have been described in the literature for postoperative pain management following PCNL. These include systemic opioids, nonsteroidal anti-inflammatory drugs (NSAIDs), and several regional analgesia techniques. However, due to their adverse effect profiles, opioids and NSAIDs are not ideal options, particularly in patients with renal dysfunction. Regional techniques that have been utilized include local infiltration, intercostal nerve blocks, paravertebral blocks, and epidural analgesia. The kidney is primarily innervated between the T10 and L1 segments, whereas the ureter receives innervation from T10 to L2. Based on this anatomical knowledge, unilateral regional blockade between T10 and L2 can provide adequate analgesia for PCNL procedures. Thoracic paravertebral block was previously a commonly preferred technique; however, it may be associated with complications such as intravascular injection, unintended epidural or intrathecal spread, and pneumothorax during its performance. In recent years, the number of reports describing the use of the erector spinae plane block (ESPB) as part of multimodal anesthesia for postoperative analgesia has increased. In ESPB, local anesthetic is injected into the interfascial plane between the transverse process of the vertebra and the erector spinae muscles, and has been reported to spread to multiple paravertebral spaces. ESPB is considered a peri-paravertebral block that can affect both visceral and somatic pain pathways. The aim of this study is to evaluate the effect of ultrasound-guided erector spinae plane block on intraoperative and postoperative opioid consumption, postoperative pain scores, and quality of recovery in patients undergoing percutaneous nephrolithotomy.

Effect of Comprehensive Spa Care on Kidney and Urological Conditions: A Clinical Study in Adult Patients

This is a single-arm, pretest-posttest study evaluating the effects of a 21-day comprehensive spa care (Komplexní lázeňská léčebně rehabilitační péče, KLP) on patients with nephrological and urological conditions treated at a spa facility in Mariánské Lázně, Czech Republic. The study enrolls 150 adult patients (75 men and 75 women), aged 40-70 years, who are prescribed KLP for indications VIII/1 (recurrent and chronic non-tuberculous inflammation of the kidneys and urinary tract), VIII/2 (nephrolithiasis without urinary tract obstruction, nephrocalcinosis), VIII/3 (conditions after kidney and urinary tract surgery), and VIII/4 (chronic prostatitis or prostatovesiculitis resistant to pharmacological treatment). The spa treatment consists of the use of natural healing resources of Mariánské Lázně, including a mineral spring drinking cure, balneotherapy (mineral water baths), peloid therapy, carbon dioxide therapy, climatotherapy, exercise therapy, and dietotherapy. The standard treatment duration is 21 days, during which each patient receives a total of 63 therapeutic procedures and drinks mineral spring water three times daily. Patients undergo assessments at the beginning (days 1-3) and at the end (days 19-21) of their treatment. Assessments include physical examination, abdominal and urinary tract ultrasound, blood and urine sampling with laboratory analysis, body composition measurement using bioelectrical impedance analysis (InBody), and psychometric questionnaire surveys. The primary aim of the study is to objectively assess the therapeutic effect of comprehensive spa care on nephrological and urological diseases by comparing pre-treatment and post-treatment clinical, laboratory, and patient-reported outcomes. The study was approved by the Ethics Committee of the University Hospital and Faculty of Medicine in Pilsen (decision of November 2, 2023, ref. no. 437/23).

Sodium Bicarbonate as an Alternative to Potassium Citrate for Kidney Stones

Kidney stones affect 1 in every 11 people in the US each year. In patients with kidney stones who are prescribed medications for stone management, only 30.2% are adherent to a medication regime and even fewer, only 13.4 % are adherent with citrate medications. Prescription potassium citrate can be expensive for many patients, leading to non-compliance. Sodium bicarbonate is a potential medication alternative that is cheaper and can potentially alkalinize the urine and/or decrease the risk of future kidney stones. However, efficacy of alternatives to potassium potassium citrate are not well studied. This study seeks to evaluate sodium bicarbonate and assess its ability to alkalinize urine in a cohort of patients with kidney stones and compare this to prescription potassium citrate.

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.

Comparison Between Different Types of Flexible Ureteroscopes

The current study aims to compare the performance of three distinct single-use digital flexible ureteroscope types in terms of cost-effectiveness, postoperative complications, operating time, and stone-free rates (SFRs).

ClearPetra™ Vacuum-assisted Ureteral Access Sheath vs Traditional Approach

Ureteroscopy has been considered the best approach when treating renal stones smaller than 2 cm. This procedure is usually performed together with ureteral access sheaths, which helps protect the ureter mucosa and lowers intrarenal pressure. Recently, a new vacuum-assisted ureteral access sheath called ClearPetra has entered US market and allows for continuous stone fragmentation and aspiration. Because there is little information on comparing this device with traditional approach (no sheath or non-vacuum-assisted sheath) in American population, we aim to compare those devices in terms of their ability to clear the kidney from kidney stones, as well as reduce infection rates postoperatively.

Comparison of Extracorporeal Shock Wave Lithotripsy Versus Retrograde Intrarenal Surgery in the Management of Renal Calculi

This study is being carried out in patients with kidney stones measuring between 1 and 2 centimeters. Kidney stones are common in Pakistan and can cause severe pain, infection, and repeated hospital visits. Two commonly used treatments for stones of this size are extracorporeal shock wave lithotripsy (ESWL) and retrograde intrarenal surgery (RIRS). ESWL uses shock waves applied from outside the body to break the stone into small fragments that can pass in the urine. RIRS is a minimally invasive endoscopic procedure in which a thin flexible scope is passed through the urinary passage into the kidney and a laser is used to break the stone. Adult patients aged 18 to 65 years with a single kidney stone of 1-2 cm will be included. According to the urologist's clinical judgment and patient preference, individuals will undergo either ESWL (Group A) as a day-care shock wave procedure or RIRS (Group B) under general anesthesia using a laser. All patients will receive standard care before and after the procedure and will be followed for 28 days. The study will compare how completely the stone is cleared (based on a CT scan), how long patients stay in hospital, how much pain they feel after the procedure, and whether they develop visible blood in the urine or signs of infection such as fever and raised white cell count. The need for any further procedure for the same stone will also be recorded. The central hypothesis is that there is a meaningful difference between ESWL and RIRS in stone clearance, safety, pain, and need for retreatment. The findings are expected to help doctors and patients choose the most suitable treatment for kidney stones of this size in routine practice.

Ultrasound Imaging of Kidney Stones and Lithotripsy

The purpose of this study is to determine whether new software processing of ultrasound images can improve detection and size determination of kidney stones.

Postoperative Analgesia Practices After Percutaneous Nephrolithotomy

This prospective observational study aims to evaluate the effectiveness and safety of different postoperative analgesia methods used in patients undergoing percutaneous nephrolithotomy (PCNL). Analgesia techniques are determined independently by the responsible anesthesiologist as part of routine clinical practice, and the study team does not intervene in treatment decisions.

Is CYP24A1 Heterozygosity a Risk Factor for Nephrolithiasis?

Biallelic loss-of-function variants in CYP24A1 have been identified as a common genetic cause of autosomal recessive hypercalcemia (ARH, ORPHA 300547, 1 in 80,000 live births), characterized by low PTH (parathyroid hormone) levels, a high 25-OH D/24,25-(OH)₂D ratio, and susceptibility to vitamin D intoxication. In humans, heterozygous pathogenic variants in CYP24A1 have been proposed both as responsible for an autosomal dominant disorder and as a risk factor for nephrolithiasis, but the rarity and heterogeneity of human data prevent a definitive answer to this crucial question. Nephrolithiasis is a complex disease in which nutritional factors - particularly sodium and protein intake (leading to hypercalciuria) - play a key role. It also has a heritability of 50%, suggesting the involvement of many genetic susceptibility factors, as well as monogenic forms (mainly autosomal recessive, but also dominant or X-linked), which have been identified in 10-20% of patients. The increasing prevalence of nephrolithiasis, affecting approximately 10% of the general population over a lifetime, has a significant financial impact on healthcare systems and imposes a major burden of morbidity, justifying further investigation into the genetic underpinnings of nephrolithiasis. The goal of the HeteroCYP project is to improve understanding of the phenotypes associated with heterozygous, compound heterozygous, and homozygous variants of CYP24A1 by comparing clinical and biological outcomes in patients according to their mutation type

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.

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.

Comparison Between Ureterorenoscopy With Lithotripsy Alone Versus Combination With Hydrogel for Kidney Stone Removal

The incidence of kidney stones (urolithiasis) has surged in both developing and developed countries, affecting approximately 15% of the global population. From 2010 to 2019, diagnoses of kidney and ureteral stones rose by 8% in Germany, 26% in France, and 15% in England. Correspondingly, the number of surgical stone removal procedures increased by 3%, 38%, and 18%, respectively. Common treatments include extracorporeal shock wave lithotripsy (ESWL), ureterorenoscopy (URS) with lithotripsy, and percutaneous nephrolithotomy (PCNL). URS, depending on stone size, has become a preferred method due to advancements in intraoperative imaging and laser technology. Despite these improvements, small fragments often remain post-intervention, leading to recurrent stones. Complete removal of all fragments is crucial to significantly reduce recurrence rates. Current literature suggests a high recurrence rate with residual fragments, impacting healthcare costs and patient quality of life. A key objective in endourological research is optimizing the stone clearance rate. Techniques like coagulum lithotomy and the autologous blood clot technique have been developed to enhance residual stone removal after laser fragmentation. These methods benefit selected patients but are not widely adopted due to complications such as reduced intraoperative visibility and long coagulum formation times. Recently, a two-component hydrogel system called mediNiK® (Purenum GmbH, Germany) was developed. This biocompatible gel can be applied through an endoscope after stone fragmentation and large fragment retrieval to embed smaller fragments and dust, forming a removable conglomerate. MediNiK® has demonstrated effectiveness in embedding and removing stone residues and is already in clinical use in Europe, showing potential for optimizing stone removal. A multicenter study has assessed the safety and tolerability of mediNiK® in standard URS (Open, randomized, multicentre study to evaluate the safety, tolerability, and performance of mediNiK® compared to standard treatment in kidney stone removal - DRKS00030532). Results indicate the gel is safe and tolerable. However, further data from larger cohorts and comparisons with conventional URS are necessary before widespread adoption of mediNiK®.

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.

Hemodynamic Effects of Surgical Position in Prone vs. Supine Percutaneous Nephrolithotomy

This prospective, randomized controlled study evaluates the hemodynamic effects of prone and supine positions during percutaneous nephrolithotomy (PNL) for large kidney stones. Surgical position may influence intraoperative and postoperative hemodynamic stability. Prone positioning can increase intrathoracic pressure and reduce venous return, whereas supine positioning may provide greater hemodynamic stability. A total of 84 patients will be randomized to undergo PNL in prone or supine positions. Primary outcomes include changes in hemodynamic parameters during surgery. Results may guide surgical position selection, especially in patients with potential hemodynamic risk.

Use of POCUS and STONE Criteria Together in the Diagnosis of Nephrolithiasis

Patients presenting to the emergency department with symptoms suggestive of renal colic will be included in the study at Kocaeli City Hospital's emergency department. Patients with nephrolithiasis considered among the preliminary diagnoses will be enrolled in the study; demographic data, vital signs, and physical examination findings will be recorded on pre-prepared standard data forms. STONE criteria scores will be calculated by emergency assistants, and bedside ultrasound will be performed for patients. Ultrasonographic findings suggestive of renal colic, such as hydronephrosis, the presence of primary stones, acoustic shadowing of the stone, the presence of twinkle artifact, presence of jet flow, and presence of bladder debris, will be evaluated, and the obtained data will be recorded on the standard data form by the performing assistant physician. In patients where computed tomography, which is the gold standard for detecting stone presence without intervention, is deemed appropriate without any intervention to the primary examining physician, the computed tomography results and ultrasound findings will be compared. The study aims to evaluate the effectiveness of bedside ultrasound application in diagnosing stone presence in patients, its success in predicting re-admission to the hospital within 1 month, its success in predicting possible alternative diagnoses and complications, in addition to the stone criteria applied in the patients.

Alpha-Blockers Prior to Ureteral Access Sheath Placement in Flexible Ureteroscopy: A Randomized Prospective Study

This study aims to evaluate whether the use of alpha-blockers before flexible ureterorenolithotripsy facilitates the passage of the ureteral access sheath. The trial will enroll adult patients diagnosed with kidney stones who are scheduled for flexible ureteroscopy. Participants will be randomly assigned to receive or not receive alpha-blockers for seven days before surgery. The primary outcome is the rate of successful sheath placement without the need for a second procedure. Secondary outcomes include the incidence of ureteral injuries and the need for additional surgical interventions. The goal is to improve surgical efficiency and patient outcomes in the treatment of kidney stones.

Thulium Fiber Laser (TFL) vs Thulio Pulsed Thulium:YAG (p-Tm:YAG)

This research study is being conducted to assess the ability and efficiency of two laser systems to break up kidney stones during ureteroscopy with laser lithotripsy for kidney stone treatment.

Evaluation of the LithoVue Elite Ureteroscope With Intra-Renal Pressure Monitoring Technology: Examination of Surgeon Behavior and Post-operative Outcomes

The goal of this study is to evaluate the influence of real-time intrarenal pressure measurement availability on surgeons' behavior during ureteroscopy while using the ureteroscope LithoVue Elite.

HoYAG vs TFL in miniPCNL With ClearPetra

Mini percutaneous nephrolithotripsy is the treatment of choice for kidney stones over 2cm. This procedure commonly uses laser energy for breaking the stones, and among possible laser platforms, Hoyag and thulium fiber laser are FDA approved. Recently, this procedure has also included the use of vacuum assisted renal access sheaths, which allows suction to be employed together with the breaking of stones. This study intends to compare outcomes when using either laser platforms with suction sheaths in participants undergoing mini percutaneous nephrolithotripsy for the treatment of kidney stones.

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.

RIRS With Flex Suction Sheath vs. PCNL for 2-3 cm Renal Stones

This is a multicenter, randomized controlled trial comparing retrograde intrarenal surgery (RIRS) using a tip-flexible suction access sheath with standard percutaneous nephrolithotomy (PCNL) for the treatment of 2-3 cm unilateral renal stones. The aim is to evaluate the clinical efficacy and safety of the novel suction sheath-assisted RIRS compared to standard PCNL in terms of stone-free rate and postoperative complications. A total of 308 patients will be enrolled across four centers in China.