Active clinical trials for "Kidney Calculi"

Patients with a ureteral or kidney stone that causes symptoms, like pain, frequently have small kidney stones that don't cause symptoms. If these small kidney stones are determined to be asymptomatic (not causing any problems or pain), then most urologists will simply remove the symptomatic ureteral stone and leave the additional stones in the kidneys. However, symptomatic kidney stones started as small stones that didn't cause symptoms. This means that the small stones remaining in the patient's kidney may cause problems later. The purpose of our research is to test if removing small stones from the kidney prevents future stone episodes.

The investigators plan to compare three different devices that are used to break up large kidney stones during surgery for removal to see if one is faster or more efficient than the others.

Percutaneous nephrolithotomy (PNL), in conjunction with intracorporeal lithotripsy, allows for the rapid removal of any kidney stone regardless of size. Currently, the choice of intracorporeal lithotripters includes ultrasonic, pneumatic, and combined ultrasonic/pneumatic energy sources. Recently, a novel dual probe design as been introduced by Cybersonics of Erie, Pennsylvania. This dual probe intracorporeal lithotrite is called the Cyberwand, and is composed of a fixed inner probe vibrating at an ultrasonic frequency with an outer probe vibrating at about 1,000 Hz. As this new design has the potential to revolutionize intracorporeal lithotripsy, we intend to compare this novel technology to currently available lithotripsy technology in a randomized clinical trial.

It is well established that uncomplicated distal ureteroscopy can be safely performed without leaving a ureteral stent. However, many urologists continue to leave ureteral stents following uncomplicated ureteroscopy, regardless of stone location, due to concerns for post-operative complications, patient symptoms and to reduce unplanned medical visits. There is a paucity of data regarding the utility of stent placement for proximal ureteral or renal stones following ureteroscopy. We have designed a prospective, randomized controlled trial to evaluate the role of ureteral stent placement following ureteroscopy and pyeloscopy in proximal and renal stones.

Shockwave lithotripsy (SWL) is a safe, non-invasive treatment for renal calculi. During SWL energy is focused on in order to break kidney stones and this energy can be varied in size from a narrow (or small) focal zone to a wide (or large) focal zone. This is a multi-centered, randomized study comparing the single treatment success rates of narrow and wide focal zones during SWL.

Kidney stone disease affects almost 10% of overall population, often requiring a surgical intervention. Currently, shock wave lithotripsy is considered a first-line treatment option for patients suffering from symptomatic kidney stones smaller than 2.0 cm, providing reasonable stone-free rate. Actually, the outcomes from SWL vary largely due to several factors including stone burden, stone density, stone-skin distance (SSD), and patient's body habitus. Furthermore, the imaging exam modality (i.e. ultrasound versus computed tomography scan) performed to assess the presence of residual fragments also impacts on SWL outcome analysis. We aim to perform a well-controlled prospective evaluation of all variables that may impact on fragmentation and clearance of lower pole calculi after SWL. These variables are assessed exclusively by a noncontrast computed tomography scan (NCCT), eliminating the necessity of an intravenous urography to study renal collecting system anatomy; an imaging exam that is not routinely performed anymore for kidney stone patients.

Thiazide diuretics will be more effective in lowering urine calcium excretion if taken at night as compared to the daytime. It will therefore be more effective in reducing kidney stone recurrence in nephrolithiasis patients with elevated urine calcium who are known to have increased risk of kidney stones at night time.

Calcium oxalate nephrolithiasis is a relatively common disease. The prevalence in the general population may range from 10 to 12 percent, and 0.4 to 1 percent of new cases are reported every year according to different series. Without specific pharmacological therapy, the recurrence rate in patient with established diagnosis of nephrolithiasis is extremely high and may range from 15 to 20 percent per year, with a cumulative incidence at five years ranging from 27 to 50 percent.Although genetic factors play an important role in the development of nephrolithiasis, environmental factors such as diet also appear to affect stone formation. Potassium citrate is also effective in preventing stone recurrence in patients with calcium oxalate nephrolithiasis. Low tolerability, however, may remarkably limit the use of these medication. Citrus fruits are a natural rich source of citrate and diet supplementation with juice of citrus fruits may represent a valuable alternative option to supply citrate without exposing the patients to the adverse effects of citrate containing medications. Among the most commonly consumed citrus fruits, lemons contain the greatest concentrations of citric acid (49,2 g/Kg);a half cup of pure lemon juice can provide a daily amount of citrate comparable to that of a standard daily dose of alkali citrate medications. A few studies tried to evaluate the effects of lemon juice supplementation in patients with calcium oxalate nephrolithiasis, but the findings were flawed by the retrospective, observational design of the study or by the too small sample size that limited the power of statistical analyses and the reliability of the results. This study will be primarily aimed at evaluating whether lemon juice added to standard diet recommendations compared to diet recommendations alone may reduce the risk of new stone formation in patients with recurrent idiopathic calcium oxalate nephrolithiasis. Secondarily, the study will evaluate the effects of lemon juice supplementation on complications of nephrolithiasis such as urinary tract infections, colic symptoms, and hospitalizations for stone disruption or removal, as well as the effects on urinary factors (such as urinary citrate, oxalate, calcium excretion or pH) that may favor or limit stone formations and the relationships between these effects and the risk of stone recurrence.

The investigators hypothesize that a 3 month course of vitamin D supplementation to treat 25(OH)D deficiency in stone formers with high levels of 24-hour urinary calcium will not increase urinary calcium excretion by greater than 10%.

The investigators plan to assess the efficacy of standard and low dose HCTZ treatment in the recurrence prevention of calcium-containing kidney stones. More specifically, the investigators aim to assess the dose-response relationship for three different dosages of HCTZ. Study intervention: HCTZ 12.5 mg, 25 mg or 50 mg once daily per os for 24 or 36 months. In addition, all patients in HCTZ treatment arms will receive state-of-the-art non-pharmacologic recommendations for stone prevention according to current guidelines. Control intervention: Placebo once daily per os for 24 to 36 months. In addition, all patients in the placebo arm will receive state-of-the-art non-pharmacologic recommendations for stone prevention according to current guidelines.