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The aim of this article was to review the most widely researched adjuvant medical therapies for the surgical management of urolithiasis. Articles were identified and reviewed from PubMed and Medline databases with MeSH headings focusing on the various surgical treatments of urolithiasis and adjuvant therapy. Additional articles were retrieved from references and conference proceedings. Surgical treatments reviewed included shockwave lithotripsy, ureteroscopy, and percutaneous nephrolithotomy. Adjuvant therapy was considered medical or complementary therapy as an adjunct to these surgical interventions. Adjuvant therapy for the surgical management of urolithiasis has been documented to increase stone-free rates, reduce stone remission rates, prevent renal damage, and decrease postoperative morbidity. A variety of agents have been studied, ranging from antioxidants to alpha-blockers and to alkalinizing agents. Additionally, there is increasing interest in complementary adjuvant therapy (ie, acupuncture). Adjuvant therapy is a fertile area for research in the surgical management of urolithiasis. The optimal agents have yet to be determined and therefore further investigation is warranted and necessary.

Context: Percutaneous nephrolithotomy (PNL) is traditionally performed with the patient in the prone position., Objective: To assess the efficacy and safety of the prone and supine positions, particularly in obese patients and in those with staghorn calculi., Evidence Acquisition: A Medline search was conducted for articles published during the last 10 yr related to PNL in the prone and supine positions., Evidence Synthesis: This search revealed 9 published studies for supine and 25 for prone PNL. None of the supine PNL studies reported visceral injuries, while transfusion rates were 0.0-9.4% and stone-free rates were 69.6-95.0%. One study of supine PNL evaluated a significant proportion of obese patients. Prone PNL studies in obese patients report transfusion rates of 3.2-8.8% and stone-free rates of 79.0-89.2%. In the only randomized study, excluding obese patients and staghorn calculi, operative time favors the supine position. A nonrandomized comparative study demonstrated similar complication rates with insignificant improvement in treatment success for supine PNL; however, when comparing series with similar proportions of staghorn calculi cases, there are slightly improved outcomes for prone PNL. Moreover, comparison of weighted means favors prone PNL., Conclusions: For obese patients and staghorn calculi, prone PNL appears to be associated with decreased operative times with similar bleeding rates and slightly better stone-free rates than supine PNL.

Purpose: Randomized controlled trials potentially provide the highest level of evidence to inform clinical decision making. Appropriate use of statistical methods is a critical aspect of all clinical research, including randomized controlled trials. We report the first formal evaluation to our knowledge of the statistical methods of randomized controlled trials published in the urological literature in 1996 and 2004., Materials and Methods: All human subjects randomized controlled trials published in 4 leading urology journals in 1996 and 2004 were identified for formal review. A standardized evaluation form was developed based on the Consolidated Standards of Reporting Trials statement. Each article was evaluated by 2 independent reviewers with formal training in research design and biostatistics who were blinded to study authors and institution. Discrepancies were settled by consensus., Results: A total of 152 randomized controlled trials were reviewed (65 in 1996, 87 in 2004). The median sample size (IQR) per arm of parallel design randomized controlled trials published in 1996 and 2004 was 36 (11, 96) and 50 (26, 134) study subjects, respectively (p = 0.157). Sample size justifications were provided by 19% of studies in 1996 and 47% of studies in 2004 (p = 0.001). Of randomized controlled trials 16 (25%) vs 32 (37%) identified a single primary outcome variable (p = 0.110). Effect size estimates for primary or secondary outcome variables were provided by 5% vs 13% (p = 0.090) and the precision of the effect was detailed by 5% vs 10% of randomized controlled trials (p = 0.195)., Conclusions: This formal review suggests that statistical analysis in urological randomized controlled trials has improved. However, considerable deficiencies remain. Ongoing education in applied statistics may further improve urological randomized controlled trial reporting.

Purpose: This article introduces practicing urologists to the critical appraisal of systematic reviews and meta-analyses to guide their evidence-based clinical practice., Materials and Methods: Using a urological clinical case scenario we introduce a 3-step process in evaluating systematic reviews and meta-analyses by considering 1) the validity of the review results, 2) what the results are, and 3) the extent to which the results can and should be applied to patient care., Results: A systematic review seeks to synthesize the medical literature about a specific clinical question using explicit methods to perform a comprehensive literature search, identify and select eligible studies, critically appraise their methods, and judiciously summarize the results considering how they vary with study characteristics. When this summary involves statistical methods, ie a meta-analysis, reviewers can offer a pooled estimate that will have greater precision and will apply more broadly than the individual studies. The quality of the underlying studies, the consistency of results across studies and the precision of the pooled estimate can considerably affect the strength of inference from systematic reviews., Conclusions: Valid systematic reviews of high quality studies can increase the confidence with which urologists and patients make evidence-based decisions. Thus, urologists need to recognize the inherent limitations, understand the results and apply them judiciously to patient care.

Purpose: We investigated urologist perceptions of barriers to implementing evidence-based medicine in clinical practice., Materials and Methods: In April 2005 an Internet survey was conducted to assess American Urological Association member attitudes toward evidence-based medicine. This analysis presents the responses to an open-ended question about perceived barriers to implementing evidence-based clinical practice in urology. Two raters developed a coding scheme with 5 main categories of evidence concerns, system level factors, physician factors, patient factors and other barriers. Each rater independently assigned a category to each response. Discrepancies were resolved by consensus., Results: A total of 365 participants (72%) responded to the open-ended question, each providing up to 4 codable responses. Of the group 53% cited concerns about the evidence including the lack thereof, low quality, limited applicability and biased presentation. In addition, 37% reported system level factors such as issues of reimbursement, fear of litigation, problems with implementation, interference/bias by third parties, and expectations and attitudes of other providers as important issues. Physician factors and patient factors were further cited by 28% and 9%, respectively. In terms of the legitimacy of evidence-based medicine 9% expressed skepticism whereas 5% of respondents indicated that they saw no barriers to implementing evidence-based medicine in urology., Conclusions: Efforts to promote evidence-based medicine in urology should focus not only on the generation of high quality clinical research but also on its unbiased reporting and timely dissemination. Concerted efforts should be made to reduce system level factors that hinder the implementation of evidence-based care.

Background and Purpose: Dietary intake of citrate in the form of citrus juices (eg, lemonade, orange juice) will enhance urinary citrate excretion, a valuable benefit for patients with hypocitraturic calcium oxalate nephrolithiasis. While information on citrate concentrations in select citrus juices is available, data on citrate concentrations of commercially available beverages (juice and otherwise) are limited. Using nuclear magnetic resonance spectroscopy (1H NMR), we report citrate concentrations of several beverages to help guide dietary recommendations aimed at increasing urinary citrate excretion and correcting hypocitraturia., Methods: Citrate concentrations of a squeezed lemon, several fruit juices, and common beverages were measured using 1H NMR. Spectra for each sample were obtained in duplicate; citrate peak was identified, measured, and quantified and compared with the citrate concentration in the juice of 1 medium lemon., Results: Quantitative analysis revealed the highest concentration of citrate was in grapefruit juice (64.7 mmol/L), followed in decreasing concentrations by lemon juice (47.66 mmol/L), orange juice (47.36 mmol/L), pineapple juice (41.57 mmol/L), reconstituted lemonade (38.65 mmol/L), lemonade flavored Crystal Light (38.39 mmol/L), ready to consume not from concentrate lemonade (38.24 mmol/L), cranberry juice (19.87 mmol/L), lemon-flavored Gatorade (19.82 mmol/L), homemade lemonade (17.42 mmol/L), Mountain Dew (8.84 mmol/L), and Diet 7Up (7.98 mmol/L), respectively., Conclusions: According to 1H NMR, all of the tested "natural" citrus juices have high concentrations of citrate (38.3-67.4 mmol/L), with grapefruit juice having the highest concentration of the beverages chosen. Lemonade flavored Crystal Light had the highest concentration of citrate in the nonjuice category of tested beverages. In patients with mild to moderate hypocitraturia, dietary supplementation with citrus-based juices may be an effective alternative to medical management while not requiring large serving sizes. Further prospective studies are warranted to evaluate the clinical significance of these findings.

Most kidney stones are composed primarily of calcium oxalate. Oxalobacter formigenes is a Gram-negative, anaerobic bacterium that metabolizes oxalate in the intestinal tract and is present in a large proportion of the normal adult population. It was hypothesized that the absence of O. formigenes could lead to increased colonic absorption of oxalate, and the subsequent increase in urinary oxalate could favor the development of stones. To test this hypothesis, a case-control study involving 247 adult patients with recurrent calcium oxalate stones and 259 age-, gender-, and region-matched control subjects was performed. The prevalence of O. formigenes, determined by stool culture, was 17% among case patients and 38% among control subjects; on the basis of multivariate analysis controlling demographic factors, dietary oxalate, and antibiotic use, the odds ratio for colonization was 0.3 (95% confidence interval 0.2 to 0.5). The inverse association was consistently present within strata of age, gender, race/ethnicity, region, and antibiotic use. Among the subset of participants who completed a 24-h urine collection, the risk for kidney stones was directly proportional to urinary oxalate, but when urinary factors were included in the multivariable model, the odds ratio for O. formigenes remained 0.3 (95% confidence interval 0.1 to 0.7). Surprisingly, median urinary oxalate excretion did not differ with the presence or absence of O. formigenes colonization. In conclusion, these results suggest that colonization with O. formigenes is associated with a 70% reduction in the risk for being a recurrent calcium oxalate stone former.

Background and Purpose: Advances in ureteroscope and stone basket design have catapulted ureteroscopy to the forefront of surgical stone management; however, persistent problems such as stone migration continue to challenge urologists. The Escape nitinol stone retrieval basket (Boston Scientific, Natick, MA) is a stone basket designed to capture calculi and facilitate simultaneous laser lithotripsy in situ. We report our initial experience with the Escape basket for the management of urinary calculi and compare the use of this device with other methods of optimizing ureteroscopic stone management., Patients and Methods: A prospective evaluation of 23 patients undergoing ureteroscopic holmium:yttrium-aluminum-garnet laser lithotripsy of urinary calculi was performed at two institutions by two surgeons (R.M. and G.M.P). The Escape basket was used to prevent retrograde ureteral stone migration or to facilitate fragmentation and extraction of large renal calculi. Patient demographics and perioperative parameters were assessed., Results: Twenty-three patients (16 men, 7 women), with a mean age of 55.5 years (range 33-74 yrs) were treated for renal (n = 9) or ureteral (n = 14) calculi. The mean stone diameter was 1.4 cm (range 0.4-2.5 cm), mean fragmentation time was 44.1 minutes (range 10-75 min), and mean energy used was 3.1 kJ (range 0.4-10.6 kJ). No complications were encountered. Eighty-seven percent (20/23) of patients were rendered completely stone free after ureteroscopic laser lithotripsy using the Escape basket. Of the three patients with residual calculi, one patient with a 2.5-cm renal calculus had residual fragments larger than 3 mm, and two patients with large renal calculi had residual fragments smaller than 3 mm., Conclusions: The Escape basket appears to be safe and effective in preventing stone migration and facilitating ureteroscopic laser lithotripsy and stone extraction.

Purpose: Surgical education is changing rapidly as several factors including budget constraints and medicolegal concerns limit opportunities for urological trainees. New methods of skills training such as low fidelity bench trainers and virtual reality simulators offer new avenues for surgical education. In addition, surgical simulation has the potential to allow practicing surgeons to develop new skills and maintain those they already possess. We provide a review of the background, current status and future directions of surgical simulators as they pertain to urology., Materials and Methods: We performed a literature review and an overview of surgical simulation in urology., Results: Surgical simulators are in various stages of development and validation. Several simulators have undergone extensive validation studies and are in use in surgical curricula. While virtual reality simulators offer the potential to more closely mimic reality and present entire operations, low fidelity simulators remain useful in skills training, particularly for novices and junior trainees. Surgical simulation remains in its infancy. However, the potential to shorten learning curves for difficult techniques and practice surgery without risk to patients continues to drive the development of increasingly more advanced and realistic models., Conclusions: Surgical simulation is an exciting area of surgical education. The future is bright as advancements in computing and graphical capabilities offer new innovations in simulator technology. Simulators must continue to undergo rigorous validation studies to ensure that time spent by trainees on bench trainers and virtual reality simulators will translate into improved surgical skills in the operating room.

Purpose: The optimal management of lower pole renal calculi is controversial. We compared shock wave lithotripsy (SWL) and ureteroscopy (URS) for the treatment of patients with small lower pole stones in a prospective, randomized, multicenter trial., Materials and Methods: A total of 78 patients with 1 cm or less isolated lower pole stones were randomized to SWL or URS. The primary outcome measure was stone-free rate on noncontrast computerized tomography at 3 months. Secondary outcome parameters were length of stay, complication rates, need for secondary procedures and patient derived quality of life measures., Results: A total of 67 patients randomized to SWL (32) or URS (35) completed treatment. The 2 groups were comparable with respect to age, sex, body mass index, side treated and stone surface area. Operative time was significantly shorter for SWL than URS (66 vs 90 minutes). At 3 months of followup 26 and 32 patients who underwent SWL and URS had radiographic followup that demonstrated a stone-free rate of 35% and 50%, respectively (p not significant). Intraoperative complications occurred in 1 SWL case (unable to target stone) and in 7 URS cases (failed access in 5 and perforation in 2), while postoperative complications occurred in 7 SWL and 7 URS cases. Patient derived quality of life measures favored SWL., Conclusions: This study failed to demonstrate a statistically significant difference in stone-free rates between SWL and URS for the treatment of small lower pole renal calculi. However, SWL was associated with greater patient acceptance and shorter convalescence.

Objectives: Ureteral stents commonly cause lower urinary tract and flank discomfort. We evaluated the use of extended release oxybutynin versus phenazopyridine versus placebo for the management of ureteral stent discomfort after ureteroscopy., Methods: Each of 60 patients who received a unilateral stent after ureteroscopy was given a blister pack containing 21 unmarked capsules of either extended release oxybutynin 10 mg, phenazopyridine 200 mg, or placebo in a prospective, randomized, and double-blinded fashion. Patients were instructed to take 1 capsule 3 times daily immediately after the procedure. Patients were given 50 tablets of oral narcotic to be taken as needed. Patients reported bothersome scores for flank pain, suprapubic pain, urinary frequency, urgency, dysuria, and hematuria on postoperative day 1, day 2, and the day of stent removal. Narcotic use was also recorded., Results: Eight patients were excluded from the analysis for stent migration necessitating early removal (1), uncontrollable pain (1), failure to complete blister pack (4), and inability to contact for follow-up surveys (2). There was no difference in bothersome score among the groups for flank pain, suprapubic pain, urinary frequency, urgency, and dysuria. The phenazopyridine group reported less hematuria on postoperative day 1 when compared with placebo, which was statistically significant. The oxybutynin group required fewer narcotics, but this finding was not statistically significant., Conclusions: Although this study failed to show a significant difference in bothersome scores among the groups, the small sample size precludes definitive conclusion. Future studies pooling these data will determine the overall treatment effect and the optimal management of ureteral stent morbidity.

Purpose: Traditional ureteral access sheaths rely on tapered dilators and the Dotter principle of axial force to gain access into the ureter. We compared the performance of a novel balloon expandable ureteral access sheath using radial dilatation with that of a conventional ureteral access sheath., Materials and Methods: Ten farm pigs underwent randomized placement of the novel sheath in 1 ureter and a conventional ureteral access sheath in the contralateral ureter followed by videotaped ureteroscopy. Acute study end points included maximum and mean force of sheath insertion and removal, saline flow rate and subjective urothelial damage following sheath insertion/inflation. Additionally, blinded reviewers rated urothelial damage on digitally recorded video following sheath removal. Chronic data included gross and histological ureteral analysis at 30 days., Results: The novel ureteral access sheath inserted with less maximum force (0.36 vs 1.48 pounds, p <0.001) and less average force (0.11 vs 0.49 pounds, p = 0.001). The flow rate during 5 minutes was higher in the new sheath (90.0 vs 80.6 cc per minute, p <0.05). Withdrawal forces were not statistically different between the sheaths. The novel sheath also had a lower subjective trauma scale rating (4.2 vs 6.1, p <0.05). Eight blinded reviewers determined that the novel ureteral access sheath resulted in less total urothelial tear length (1.3 vs 2.7 cm, p = 0.03) and less visible ureteral damage in all animals except 1 (p = 0.04)., Conclusions: The novel balloon expandable ureteral access sheath had easier insertion and a better flow rate, and caused less urothelial trauma in this porcine model. This ureteral access sheath offers a promising new option for ureteral access. A randomized clinical trial is in progress to assess the benefits of this new ureteral access sheath.

Purpose: Previous studies suggest that intravesical administration of nonsteroidal anti-inflammatory drugs may reduce the troublesome voiding symptoms and pain related to ureteral stenting. The objective of this study was to investigate the effectiveness of a long-acting local anesthetic, ropivacaine, injected submucosally into the bladder to control ureteral stent-associated symptoms., Materials and Methods: A randomized, single-blinded, study approved by our Institutional Review Board of adult patients scheduled for ureteroscopic stone surgery and possible stent placement was conducted. Patients were randomized to either the treatment cohort, who received five injections of 2 mL 0.5% ropivacaine around the ureteral orifice or to the control cohort, who received five injections of 2 mL of 0.9% normal saline in identical locations. Pain scale questionnaires were provided to each subject preoperatively and at postoperative hours 2, 4, 8, 24, and 48 as well as on the day of stent removal. Student's t test and Wilcoxon signed rank sum tests were used for Gaussian and nonparametric data, respectively., Results: Twenty-two patients were randomized evenly into the two cohorts. The ropivacaine group consisted of 11 patients (eight men and three women) with a mean age of 56.2 years (standard deviation [SD] = 12, range 27-69), and the saline group consisted of eleven patients (six men and five women) with a mean age of 47.8 years (SD = 6.6, range 37-58). Intraoperative parameters appeared similar between the two cohorts. Intraoperative and postoperative narcotic usage was not different between the two groups, except at postoperative hour 2 when it favored the ropivacaine cohort (P = 0.05). Trends favoring ropivacaine in flank pain, bladder pain, genitalia pain, and hematuria domains were seen as long as 8 hours and up to the day of stent removal. Trends of less magnitude and duration were seen in the dysuria domain. No differences were seen in the frequency and urgency domains., Conclusions: Our preliminary investigation with intravesical injection of ropivacaine before ureteroscopic surgery demonstrated trends toward decreased pain and voiding symptoms in this small-sample study. Inclusion of a larger sample should definitively address the effectiveness of intravesical ropivacaine and its impact on stent-related symptoms.

Surgical management of stones in anomalous kidney presents a problem for urologic surgeons. Various minimally invasive management options have been previously reported including shock wave lithotripsy (SWL), percutanteous nephrolithitomy (PNL), as well as ureteroscopy. While all of their techniques work well in select populations, recent improvements in endoscopic technology and intracorporeal lithotripsy make ureteroscopy possible for most cases of stones in ectopic, pelvic, or transplant kidneys. Additionally, many of the limitations of shock wave lithotripsy and/or percutaneous neprholithotomy can be overcome with a ureteroscopic approach. As new endoscopic technology and adjunctive device developments continue to enter the urologist's armamentarium the role of ureteroscopy continues to expand. Once unapproachable stones may now be addressed via flexible ureteroscopes, improved baskets, and holmium lasers. In conclusion ureteroscopic management of urolithiasis in anomalously located kidneys is a viable approach. Success rates are similar to those reported for SWL and the morbidity is less than PNL. With increasing dissemination of ureteroscopic skills, improved technology and enhanced adjunctive devices (i.e.; sheaths and baskets), ureteroscopy should play a larger role in the management of these challenging patients, with subsequently reduced patient morbidity.

Purpose: Reference values for stone risk factors in 24-hour urine samples for nonstone forming children are limited. We measured urinary stone risk factors in healthy children 3 to 18 years old, and sought to determine whether the risk factors are affected by age., Materials and Methods: A total of 48 healthy subjects with no history of stone disease, endocrine abnormalities or urological surgery were recruited from the Naval Medical Center in San Diego. Subjects were then further divided into 4 age groups, each separated by 5 years. A single outpatient 24-hour urine sample was obtained and analyzed. Urine chemistries were adjusted for urinary creatinine and body weight., Results: After excluding under collected samples 46 urine samples were analyzed. Urinary pH and volume decreased with increasing age, although the difference in pH did not reach statistical significance. Unadjusted urinary parameters failed to show statistical difference among the age groups. When adjusted for urinary creatinine and body weight all urinary parameters (calcium, oxalate, uric acid, citrate, magnesium, sodium, phosphorus and potassium) decreased with increasing age (statistically significant except for calcium)., Conclusions: Stone risk factors in 24-hour urine samples decrease with increasing age in healthy, nonstone forming children. Normative data, derived by adjustment with urinary creatinine or body weight and stratified according to quintiles of age, should be useful in defining abnormal stone risk factors in children with stones.

Purpose: In this systematic review we summarize information on animal models of stone formation, the similarities of stone formation between humans and nonhuman animals, and the management of naturally occurring stones in animals, particularly dogs and cats., Materials and Methods: A comprehensive review of the peer reviewed literature was performed using the key words urolithiasis and animals. The search was then limited to articles in English that were published within the last 30 years (1977 to 2007)., Results: Multiple animal species are affected by urolithiasis and the mechanisms of formation appear to mirror those in humans. Recently described models of animal stone disease may help us better understand and ultimately treat nephrolithiasis in humans., Conclusions: The pathogenesis of urolithiasis and treatment protocols in animals parallel those of humans. Given the number of similarities between treatment patterns for humans and animals, many urologists are now being integrated into the treatment of animals.

Background: Controversy exists regarding the need for ureteral stent insertion after routine ureteroscopic stone surgery. We designed a questionnaire to assess and better understand the practice patterns of urologists for stent applications., Materials and Methods: A 26-question survey was distributed to 570 community and academic urologists. The answers were anonymously tabulated to determine the practice patterns for stent placement., Results: Of the 173 respondents, 97.7% performed ureteroscopic surgery, with the majority (77%) performing 1 to 10 procedures per month. Sixty-eight percent of urologists considered more than 70% of their ureteroscopic procedures "routine." Only 21% of urologists dilated the ureteral orifice more than 90% of the time. Those who dilated the ureteral orifice used a balloon (43%), ureteral access sheath (13.5%), or both (21%). The use of an access sheath did not change stenting practices for 75% of urologists. Patterns vary with regard to length of indwelling time, with 85% of urologists maintaining the stent for fewer than 7 days. Most urologists use either cystoscopy (42%) or pull-suture in clinic (37%) to remove stents. Patient tolerance is the most significant problem with stents reported by 97.6% of urologists. The respondents were divided into three experience-based groups: group 1, <2 years of experience; group 2, 2 to 10 years; and group 3, >10 years. Using Fisher's exact test, there were no statistically significant differences between the groups., Conclusion: A wide variability exists among urologists in the practice patterns of stent insertion after routine ureteroscopic surgery. Most consider their procedures routine and are more likely to place stents after ureteral dilation despite growing evidence to the contrary. Knowledge of the varied practices may aid less experienced urologists in their decision to insert a stent after ureteroscopy.

Purpose: The goal of treating ureteral calculi is to achieve complete stone clearance with minimal patient morbidity. Shock wave lithotripsy and ureteroscopy have become standards of care for ureteral calculi. However, the optimal choice of treatment depends on various factors, including stone size, composition and location, clinical patient factors, equipment availability and surgeon capability. Indications for and outcomes data on shock wave lithotripsy and ureteroscopy for proximal ureteral calculi were reviewed to provide recommendations on the optimal treatment choice for managing symptomatic ureteral calculi., Materials and Methods: A systematic review was performed based on an English literature search using the MEDLINE database between 1997 and 2005. The key words used were proximal ureteral calculi, ureteroscopy and shock wave lithotripsy., Results: A total of 87 articles were identified, of which 33 were selected for inclusion. Shock wave lithotripsy and ureteroscopy provided an excellent stone-free rate (86% to 90%) for stones less than 10 mm, whereas for larger stones ureteroscopy achieved better outcomes vs shock wave lithotripsy (67% vs 73%). Ureteroscopy was preferred over shock wave lithotripsy in patients with pregnancy or bleeding diathesis., Conclusions: Ureteroscopy provides optimal stone clearance in patients with proximal ureteral calculi more than 10 mm. It is also recommended in patients with contraindications for shock wave lithotripsy. In patients with smaller stones (less than 10 mm) shock wave lithotripsy may be considered a reasonable alternative with outcomes similar to those of ureteroscopy.

Purpose: The concept of levels of evidence is one of the guiding principles of evidence based clinical practice. It is based on the understanding that certain study designs are more likely to be affected by bias than others. We provide an assessment of the type and levels of evidence found in the urological literature., Materials and Methods: Three reviewers rated a random sample of 600 articles published in 4 major urology journals, including 300 each in 2000 and 2005. The level of evidence rating system was adapted from the Center of Evidence Based Medicine. Sample size was estimated to detect a relative increase in the proportion of studies that provided a high level of evidence (I and II combined) from 0.2 to 0.3 with 80% power., Results: Of the 600 studies reviewed 60.3% addressed questions of therapy or prevention, 11.5% addressed etiology/harm, 11.3% addressed prognosis and 9.2% addressed diagnosis. The levels of evidence provided by these studies from I to IV were 5.3%, 10.3%, 9.8% and 74.5%, respectively. A high level of evidence was provided by 16.0% of studies in 2000 and by 15.3% in 2005 (p = 0.911)., Conclusions: This study suggests that a majority of studies in the urological literature provide low levels of evidence that may not be well suited to guide clinical decision making. We propose that editors of leading urology journals should promote awareness for this guiding principle of evidence based clinical practice by providing a level of evidence designation with each published study.

Purpose: Evidence based clinical practice has been defined as the conscientious, explicit and judicious use of the current best evidence in making decisions about the care of individual patients. It refers to a broad set of principles and methods intended to ensure that medical decisions, guidelines and health policy are based on well designed studies of therapeutic effectiveness and benefit., Materials and Methods: We review the principles and practice of evidence based clinical practice using examples from the urology literature. We further provide a guide to currently available web based evidence based clinical practice resources and guidelines for urologists., Results: Evidence based clinical practice integrates a hierarchy of evidence and patient values with practitioner judgment to guide decision making for the individual patient. Important steps in the evidence based clinical practice process include the formulation of an answerable question and a systematic search of the literature. In the absence of pre-appraised evidence or disease specific guidelines, the practice of evidence based clinical practice relies heavily on the evaluation of the primary literature by the individual urologist. Depending on the question domain (therapy/prevention, etiology/cause/harm, diagnosis or prognosis) and study design, a given study is critically appraised for validity, impact and applicability. Evidence is then integrated with clinical judgment, and patient circumstances and preferences. Finally, the practice of evidence based clinical practice includes a self-assessment of provider performance., Conclusions: Knowledge, practice and documentation of evidence based clinical practice are of increasing importance to every urologist. Urologists should embrace evidence based clinical practice principles by acquiring the necessary skills to critically appraise the literature for the best evidence applicable to patient care.

Objective: To assess possible underlying metabolic abnormalities in three sets of monozygotic twins, to evaluate the interplay among the factors of kidney stone formation, a complex multifactorial process influenced by environmental, genetic and anatomical factors., Patients and Methods: Three sets of identical twins with either cystine or calcium oxalate stones were identified. Demographic data, medical histories and the results of 24-h urine testing, with samples collected on self-selected diets, were reviewed and analysed., Results: The cystinuric twins had very similar cystine excretion rates, while stone activity was significantly more pronounced in one. Metabolic abnormalities were concordant in one set of twins with calcium oxalate stones, both being hypercalciuric and hyperuricosuric. However, metabolic abnormalities were discordant in the other pair, one twin with hypercalciuria and the other with hypocitraturia. Two of the three pairs had low urinary volume., Conclusions: These results support previous observations that environmental, genetic and potentially, anatomical factors play roles in kidney-stone formation. Additional controlled studies of monozygotic stone-forming twins might help to define the interplay between environmental and genetic factors, and allow the identification of susceptibility genes involved in stone generation.

Purpose: Recent studies have shown a significant decrease in patient reported pain scores when the nephrostomy tube size is decreased from 22 to 10Fr. We hypothesize that patient reported pain and narcotic use could be further decreased for patients with post-percutaneous nephrolithotomy nephrostomy tubes if the incision is infiltrated with a local anesthetic., Materials and Methods: A randomized prospective trial was designed to assess the impact of Marcaine infiltration of the nephrostomy tract following percutaneous stone removal. Patients undergoing single access percutaneous nephrolithotomy were randomized to have a fixed volume of saline or weight based concentration of Marcaine infiltrated into the nephrostomy tube tract at the conclusion of the procedure. Postoperative narcotic use and patient reported pain scores were then obtained at 2, 4, 24 and 48 hours postoperatively., Results: A total of 25 patients were enrolled in the study with 3 excluded from analysis due to incomplete data collection (2) or the development of hydrothorax (1). Of the 22 patients analyzed 10 were in the Marcaine cohort and 12 were in the saline cohort. Patient pain scores at 2, 4, 24 and 28 hours for the Marcaine group were 5, 4.2, 3.6 and 2.6, while for the saline group scores were 3.3, 3.1, 2.3 and 3.5. At all points differences between the groups were not statistically significant (p >0.05). Mean postoperative narcotic use was 24.7 mg morphine sulfate in the Marcaine group and 32.1 mg morphine sulfate in the control cohort (p >0.05)., Conclusions: In this preliminary pilot study no significant differences in patient reported pain scores were observed. However, a trend toward decreased postoperative narcotic use was seen in patients receiving subcutaneous Marcaine administration around the nephrostomy tube tract. Further studies are warranted to define additional measures to reduce discomfort in those requiring nephrostomy tube drainage following percutaneous nephrolithotomy.

This monograph reviews the basic principles of shock wave lithotripsy. The focus is on new research on stone fragmentation and tissue injury and how this improved understanding of shock-wave technology is leading to modifications in lithotripsy that will allow this therapy to be a safer, more effective treatment for nephrolithiasis.

The efficiency and safety profile of the holmium laser has made this tool a versatile multi-purpose instrument for use in the endoscopic treatment of a wide variety of urologic disorders, in particular urinary calculi. Herein we review holmium laser physics, current endourologic laser lithotripsy applications, and the performance of new low power holmium laser devices.

Purpose: Percutaneous nephrolithotomy is a commonly used procedure for treatment of large or complex renal calculi. In some instances postoperative residual stone fragments are an unavoidable result. Yet to our knowledge no study has examined the impact of medical management on stone formation in patients with or without residual fragments following percutaneous nephrolithotomy. Thus, we have conducted the first investigation of aggressive medical management following percutaneous nephrolithotomy and its impact on stone formation rates in patients with and without residual fragments., Materials and Methods: A total of 70 patients who underwent percutaneous nephrolithotomy and received counseling regarding selective medical management following a comprehensive metabolic evaluation, were identified. Patients were placed into 4 groups following percutaneous nephrolithotomy, that is stone-free or residual fragments, who underwent or did not undergo medical therapy. New stone formation was assessed by spontaneous stone passage in the absence of residual stone fragments, stone passage without change in the number of residual fragments, surgical removal of newly formed stones, or appearance of new stones or increase in size of stone or fragments on abdominal radiographs. Stone remission rates were also calculated., Results: Selective medical therapy significantly decreased stone formation rates in the stone-free (0.67 stones per patient per year vs 0.02) and residual fragment groups (0.67 stones per patient per year vs 0.02) as determined by the Wilcoxon signed rank test (p<0.0001). Moreover, remission was observed in a higher proportion of patients in the medically treated stone-free and residual fragment groups (87% and 77%) when compared to the same groups without medical therapy (29% and 21%, chi-square test p<0.0001)., Conclusions: Our findings suggest that comprehensive metabolic evaluation and aggressive medical management can control active stone formation and growth in patients with or without residual stone fragments after percutaneous nephrolithotomy. Given the inherent morbidity and increased costs attendant with repeat procedures, medical management should be instituted in patients following percutaneous nephrolithotomy without regard to stone-free status.

Purpose: Citrus fruits and juices are a known natural source of dietary citrate. Of all the citrus juices, lemon juice appears to have the highest concentration of citrate. Therefore, lemonade therapy has been proposed as a potential treatment for patients with hypocitraturia. We retrospectively evaluated the impact of long-term lemonade therapy on urinary metabolic parameters and stone formation in patients with hypocitraturic nephrolithiasis., Materials and Methods: A total of 32 patients were identified as being on long-term lemonade therapy for hypocitraturic nephrolithiasis. The 11 patients on lemonade therapy who met the entrance criteria for evaluation were compared to an age and sex matched control group of patients treated with oral slow release potassium citrate. Pre-therapy and post-therapy urinary parameters were recorded for both groups. The effect of lemonade therapy on stone burden and stone formation rate was calculated. New stone formation was defined as passage, surgical removal or appearance of new stones, or an increase in the size of existing stones on radiographic imaging., Results: Four males and 7 females (mean age 52.7 years) were treated with lemonade therapy for a mean of 44.4 months. The control group consisted of 4 males and 7 females (mean age 54.5 years) treated with potassium citrate for a mean of 42.5 months. Of the 11 patients on lemonade 10 demonstrated increased urinary citrate levels (mean increase +383 mg per day, p <0.05). All potassium citrate therapy subjects demonstrated an increase in urinary citrate (mean increase +482 mg per day, p <0.0001). Mean pretreatment and posttreatment stone burden in the lemonade group was 37.2 and 30.4 mm(2), respectively (p >0.05). During lemonade therapy the stone formation rate decreased from 1.00 to 0.13 stones per patient per year (p >0.05)., Conclusions: Due to its significant citraturic effect, lemonade therapy appears to be a reasonable alternative for patients with hypocitraturia who cannot tolerate first line therapy. Future study in the form of a prospective, randomized trial is needed to validate these findings.

Purpose: Scant information has been published describing the effect of laser fiber distance from the stone target on the mechanism of calculus fragmentation. Using high speed photography and acoustic emission measurements we characterized the impact of laser fiber proximity on stone comminution. We evaluated the effect of laser fiber distance from the stone target on resultant cavitation bubble formation and shock wave generation., Materials and Methods: Stone fragmentation was assessed using a FREDDY (frequency doubled double pulse Nd:YAG) (World of Medicine, Orlando, Florida) laser and a holmium laser. The FREDDY laser was operated using a 420 microm fiber at an output energy of 120 and 160 mJ in single and double pulse settings, and a pulse repetition rate of 1 Hz. The holmium laser was operated using a 200 microm fiber at an output energy of 1 to 3 J and a pulse repetition rate of 1 Hz. The surface of a 1 cm square BegoStone (Bego, Bremen, Germany) attached to an X-Y-Z translational stage was aligned perpendicular to the laser fiber, which was immersed in a Lucite tank filled with water at room temperature. An Imacon 200 high speed camera was used to capture transient cavitation bubbles at a framing rate of up to 1,000,000 frames per second. Acoustic emission signals associated with shock waves generated during the rapid expansion and collapse of the cavitation bubble were measured using a 1 MHz focused ultrasound transducer., Results: At laser fiber distances of 3.0 mm or less cavitation bubbles and shock waves were observed with the FREDDY laser. In contrast to the holmium laser, the bubble size and shock wave intensity of the FREDDY laser was inversely related to the fiber-to-stone distance over the range tested (0.5 to 3.0 mm)., Conclusions: While bubble size was noted to increase with a larger stone-to-fiber distance using the holmium laser, to consistently generate cavitation bubbles and shock waves using the FREDDY laser the laser fiber should be operated within 3.0 mm of the target stone. These findings have significant implications during clinical laser stone fragmentation.

Purpose: Recent studies suggest that the incidence of renal stone formation has been increasing and the male predominance of nephrolithiasis is decreasing, which may be due to changes in diet and lifestyle. We examined changes in the prevalence by gender of inpatient hospital discharges for urinary stone disease., Materials and Methods: The Nationwide Inpatient Sample was used for analysis. Discharges with an International Classification of Diseases, 9th revision, Clinical Modification principal diagnosis of 592.0 (calculus of kidney) or 592.1 (calculus of ureter) from 1997 to 2002 were included in the investigation., Results: An estimated mean+/-SE 1,013,621+/-19,310 discharges for stone disease occurred from 1997 to 2002. Discharges for renal calculus increased by 18.9% during the study period (p<0.001), while discharges for ureteral calculus remained relatively constant. After adjusting for population changes discharges for renal calculi increased by 14.2% (p=0.002). In females discharges for renal calculi increased by 21.0% and discharges for ureteral calculi increased by 19.2% (each p<0.001). After adjusting for population changes renal calculus and ureteral calculus discharges in females increased by 22.0% (p=0.001) and 14.5% (p=0.005), respectively., Conclusions: In this nationally representative sample the population adjusted rate of discharges for stone disease in females dramatically increased from 1997 to 2002. This alteration represents a change in the prevalence by gender of treated stone disease from a 1.7:1 to 1.3:1 male-to-female ratio. It may reflect variations in the underlying prevalence by gender of stone disease. We speculate that the increasing incidence of nephrolithiasis might be due to lifestyle associated risk factors, such as obesity.

Purpose: Randomized, controlled trials are the gold standard for evidence based assessment of therapeutic interventions. In 1996 the Consolidated Standards of Reporting Trials statement was published in an effort to standardize the reporting of clinical trials. To our knowledge we report the first systematic assessment of randomized, controlled trial quality in the urology literature by Consolidated Standards of Reporting Trials standards., Materials and Methods: All human subject randomized, controlled trials published in 4 leading urology journals in 1996 and 2004 were identified for formal review. A standardized evaluation form was developed based on the Consolidated Standards of Reporting Trials statement. Each article was evaluated by 2 independent reviewers and discrepancies were settled by consensus. A Consolidated Standards of Reporting Trials criteria summary score was calculated on a scale of 0 to 22., Results: A total of 152 randomized, controlled trials met inclusion criteria. The mean+/-SEM Consolidated Standards of Reporting Trials summary score was 10.2+/-0.3 (median 10.3) and 12.0+/-0.3 (median 12.2) in 1996 and 2004, respectively, with a mean difference of 1.8 (95% CI 1.0, 2.6; p=0.001). Reporting of important methodological criteria, eg sample size justification and randomization implementation, improved from 1996 to 2004. Improvement notwithstanding, reporting of key methodological criteria remained consistently below 50% in 2004., Conclusions: This formal review suggests that randomized, controlled trial reporting in the urology literature has improved since the publication of the Consolidated Standards of Reporting Trials statement in 1996. Certain areas, such as reporting of trial methods, continue to meet Consolidated Standards of Reporting Trials criteria in fewer than half of publications. Ongoing graduate and postgraduate education in trial design and evidence based practice may result in further improvement in randomized, controlled trial reporting.

Background and Purpose: The management of acute renal colic is a problem commonly encountered by both urologists and emergency medicine physicians. The classic approach to managing uncomplicated acute renal colic involves hydration, along with imaging and pain control. Previous studies have suggested that hydration has a significant impact on patient comfort, as well as spontaneous stone passage. This study evaluated the effects of maintenance v forced hydration and its effect on the pain experienced from renal colic., Patients and Methods: Forty male and 18 female patients with a mean age of 41 years suspected to have acute renal colic were identified in the emergency department. After screening and informed consent, the patients were enrolled in the study, and 43 patients were eventually available for analysis. Patients received intravenous (IV) analgesia, imaging with a noncontrast CT scan of abdomen and pelvis, and assignment to either forced IV hydration with 2 L of normal saline over 2 hours (N = 20) or minimal IV hydration at 20 mL of normal saline per hour (N = 23). A visual analog pain scale was completed hourly for a total of 4 hours. Demographic information, laboratory and imaging results, narcotic use in morphine equivalents (ME), and pain scores were recorded and compared. Spontaneous stone passage rates were also calculated by careful patient follow-up. Results were considered statistically significant at p < 0.05., Results: Stone size was equivalent in the two treatment groups (p > 0.05). There was no difference in the narcotic requirement in ME (p = 0.644) between the two groups. Similarly, there was no difference in hourly pain score or stone-passage rates between the groups (p > 0.05)., Conclusions: Treatment of uncomplicated renal colic has traditionally included vigorous intravenous hydration, as well as medications for the control of pain and nausea. Our data suggest that maintenance intravenous fluids are as efficacious as forced hydration with regard to patient pain perception and narcotic use. Moreover, it appears the state of hydration has little impact on stone passage.

Purpose: We investigated the attitudes and opinions of urologists toward evidence-based medicine., Materials and Methods: In April of 2005 we contacted members of the American Urological Association listed with an e-mail address to participate in a web based survey. Participants were asked to characterize their level of agreement with statements referring to the role of evidence-based medicine in urology, to indicate their level of understanding of 15 evidence-based medicine related terms and to report their familiarity with 6 evidence-based medicine related resources., Results: Of 8,100 American Urological Association members 714 (8.8%) responded to this survey. There was widespread agreement (median score 9) with the concept that evidence-based medicine improves patient care and that every urologist should be familiar with critical appraisal techniques. Select terms such as median/mean, selection bias and type I error were well understood ("understand and could explain to others") by 86%, 57% and 17%, respectively. The American Urological Association Best Practice Guidelines were the single best known resource that 91% of respondents reviewed or used regularly., Conclusions: To our knowledge this survey represents the first evidence-based medicine survey of a large international group of urologists. Its results indicate that evidence-based medicine is viewed favorably and that the American Urological Association Best Practice Guidelines present a well accepted instrument for the dissemination of evidence-based medicine in urology. However, given the low response rate and the potential for selection bias, interpretation of these results must be performed with caution. Future efforts should be directed toward providing increased opportunities for urologists to learn the principles of critical appraisal, facilitating the application of evidence-based medicine in the community and promoting high quality research.

Background and Purpose: Shockwave lithotripsy (SWL) has become a first-line intervention for treatment of nephrolithiasis. However, few studies have examined the effects of modifications in the method of shockwave energy administration on comminution efficiency. We propose that a gradual increase in output voltage will produce superior stone fragmentation in comparison with a constant or a decreasing output voltage by optimizing the stress wave and cavitation erosion forces on renal calculi., Materials and Methods: BegoStone phantoms were implanted in the renal pelvis of 11 pigs that underwent SWL at a pulse repetition rate of 1 Hz. Animals in the increasing strategy group (N = 4) were subjected to 18, 20, and 22 kV for 600, 600, and 800 shocks, respectively. The second group (N = 4) received a decreasing strategy of 22, 20, and 18 kV for 800, 600, and 600 shocks, respectively. The third group (N = 3) received all 2000 shocks at 20 kV, mimicking the clinical protocol., Results: A progressively decreasing strategy and constant output voltage produced a mean comminution efficiency, or percentage of stone fragments <2 mm, of 89.0% +/- 3.3% and 87.6% +/- 1.7%, respectively. The mean comminution efficiency was improved to 96.5% +/- 1.4% by using the increasing strategy (P = 0.01)., Conclusions: A progressive increase in lithotripter output voltage during SWL can produce greater stone fragmentation than protocols employing constant or decreasing output voltage.

Recent advances in fiber optics and digital technology have dramatically improved the ability of the urologic surgeon to accurately image and document endoscopic and laparoscopic procedures. In addition, the development of digital endoscopes has expanded the armamentarium of the endoscopic surgeon greatly. Finally, new virtual reality technology has allowed increased visualization during surgery and provides excellent training for surgeons. This article details new imaging and documentation technology currently utilized during urologic procedures.

We describe a simple and effective method using the Stone Cone to prevent migration of stone fragments into the ureter during percutaneous nephrolithotomy. This maneuver may reduce the need for antegrade ureteroscopy to remove residual fragments, thereby saving time and obviating the need for placement of an occlusion balloon.

Xanthine calculi are uncommonly encountered stones. When they occur, they typically do so in association with inborn metabolic disorders such as hereditary xanthinuria or Lesch-Nyhan syndrome. They may also occur in association with states of profound hyperuricemia such as myeloproliferative disease after treatment with allopurinol. If the underlying disorder is not addressed, a high risk of stone recurrence exists. Therefore, to raise clinical awareness, we reviewed and report our experience in the treatment of patients with these stones, discussing the underlying pathophysiology and approach to treatment.

Renal calculi in the spinal cord injury population present a diagnostic dilemma for urologists. However, 7% of all patients with spinal cord injury will develop renal calculi. Undiagnosed stone disease can lead to significant morbidity and mortality in this population. This case demonstrates the subtlety of the presenting symptoms of renal calculi in the patient with spinal cord injury.

Objective: To review the metabolic analyses of patients with calyceal diverticular stones who had surgical treatment of their calculi and to examine the effect of selective medical therapy on stone recurrence, as recent reports suggest that metabolic abnormalities contribute to stone development., Patients and Methods: In all, 37 patients who had endoscopic treatment of symptomatic calyceal diverticular calculi were retrospectively reviewed. Stone composition and initial 24-h urine collections (24-h urinary volumes, pH, calcium, sodium, uric acid, oxalate, citrate, and the number of abnormalities/patient per collection) were compared with 20 randomly selected stone-forming patients (controls) with no known anatomical abnormalities. Stone formation rates before and after the start of medical therapy were calculated in the patients available for follow-up., Results: Twelve of the diverticulum patients (five men and seven women) had complete 24-h urine collections, all of whom had at least one metabolic abnormality. Seven patients had hypercalciuria, four had hyperuricosuria and three had mild hyperoxaluria. The most common abnormality was a low urine volume; 11 of the 12 patients had urine volumes of <2000 mL/day (range 350-1950). Ten patients had hypocitraturia in at least one of the two 24-h urine samples; seven had low urinary citrate levels (172-553 mg/day) on both samples. The findings were similar in the control group. The diverticulum patients had 3.1 abnormalities/patient, and the controls had 2.9 abnormalities/patient (P > 0.05). No patients had gouty diathesis and none developed cystine stones. Stone analyses were similar in the two groups; both developed either calcium oxalate or mixed calcium oxalate/calcium phosphate stones. Six patients were followed for a mean of 23.1 months while on selective medical therapy; only one passed any additional stones, thought to be existing calculi, for a remission rate of five of six (83%)., Conclusions: All patients with symptomatic calyceal diverticular stones who had comprehensive metabolic evaluation had metabolic abnormalities. There were similar abnormalities in the control random stone-formers. The abnormalities were corrected with selective medical therapy, as shown by the high remission rate. We recommend that, for patients with symptomatic calyceal diverticular calculi, a metabolic evaluation should be considered to determine stone forming risk factors.

Current ureteroscopic intracorporeal lithotripsy devices and stone retrieval technology allow for the treatment of calculi located throughout the intra-renal collecting system. Difficulty accessing lower pole calculi, especially when the holmium laser fiber is utilized, is often encountered. Herein we review our experience where lower pole renal calculi were ureteroscopically managed by holmium laser fragmentation, either in situ, or by first displacing the stone into a less dependent position with the aid of a nitinol stone retrieval device. Lower pole stones less than 20 mm can be primarily treated by ureteroscopic means in patients: that are obese; have a bleeding diathesis; with stones resistant to shockwave lithotripsy (SWL); with complicated intra-renal anatomy; or as a salvage procedure after failed SWL. Lower pole calculi are fragmented with a 200 microm holmium laser fiber via a 7.5 F flexible ureteroscope. For those patients where the laser fiber reduced ureteroscopic deflection, precluding re-entry into the lower pole calyx, a 1.9 F nitinol basket is used to displace the lower pole calculus into a more favorable position, thus allowing for easier fragmentation. A nitinol device passed into the lower pole, through the ureteroscope, for stone displacement cause only a minimal loss of deflection and no significant impact on irrigation. Eighty-five percent of patients were stone free by IVP or CT scan performed at 3 months. Ureteroscopic management of lower pole calculi is a reasonable alternative to SWL or percutaneous nephrolithotomy (PNL) in patients with low volume stone disease. If the stone cannot be fragmented in situ, nitinol basket or grasper retrieval, through a fully deflected ureteroscope, allows for repositioning of the stone into a less dependant position, thus facilitating stone fragmentation.

Free radical formation plays a major role in shock wave lithotripsy induced renal damage. Moreover, previous studies suggest that free radicals may also promote de novo calcium oxalate crystallization of previously damaged urothelium. Citrate is a known inhibitor of renal stone formation and has also been used as a free radical scavenger. Using an in vitro model with Madin-Darby canine kidney (MDCK) cells, we investigated the influence of two free radical scavengers, citrate and vitamin E, on the prevention of the shock wave-induced free radical surge. Suspensions of MDCK cells were placed in containers for shock wave exposure. Six groups of six containers each were examined: (a) no scavengers 0 shocks, (b) no scavengers 100 shocks, (c) citrate 0 shocks, (d) citrate 100 shocks, (e) vitamin E 0 shocks, (f) vitamin E 100 shocks. An unmodified HM3 was used to deliver 100 shocks at 24 kV. The cell groups that were not shocked acted as the control group and were handled identically, except for the lack of shock wave exposure. After shock wave administration, the containers were emptied and cell suspensions were immediately centrifuged. The supernatant was examined for lactate dehydrogenase (LDH) and 8-isoprostane (8-IP), markers of cellular injury and free radical formation, respectively. Intracellular LDH uniformly increased in all groups exposed to shock wave energy. Similarly, 8-IP increased in all shocked groups. However, the 8-IP increase was significantly reduced when the free radical scavengers were employed. As citrate is a well-known inhibitor of calcium nephrolithiasis, its mechanism of action may be further enhanced, based on its ability to reduce free radical formation, by a protective effect on the urothelium. These data further support the use of citrate based medications during the peri-operative period of shock wave lithotripsy, not only to inhibit stone formation and facilitate fragment passage, but also to reduce the incidence of shock wave induced renal damage. Further studies are warranted to clinically test this hypothesis.

Purpose: Robot assisted prostatectomy (RAP) is more costly than traditional radical retropubic prostatectomy (RRP) under the cost structures at certain hospitals. However, this finding may not be the case in all care settings. We investigated the sensitivity of RAP and RRP inpatient costs to variations in length of stay (LOS), local hospitalization costs and robotic case volume in the specialist and generalist settings., Materials and Methods: We developed a model of RAP vs RRP costs in the specialist and generalist settings using published data on operative time and LOS, and cost data from our academic medical center. All inpatient cost centers were included, namely surgery costs, professional fees, postoperative care, robotic equipment and service. Extensive 1 and 2-way sensitivity analyses were performed., Results: Our base case model demonstrated a cost premium for RAP vs RRP of USD $783 and $195 in the specialist and generalist settings, respectively. Sensitivity analysis of our model assumptions demonstrated that RAP could achieve cost equivalence with RRP at a surgical volume of 10 cases weekly. If case volume increased to 14 cases weekly, RAP would be less expensive than RRP in some practice settings in which RAP LOS was less than 1.5 days., Conclusions: The inpatient costs of robotic assisted prostatectomy are volume dependent and cost equivalence with generalist radical retropubic prostatectomy is possible at higher volume RAP specialty centers. While RAP may be cost competitive with RRP at high cost hospitals or high volume RAP specialist centers, this procedure would exist at a cost premium to RRP in other practice settings.

Purpose: We report the results of a controlled survival study in a porcine model investigating Tisseel or a combination of FloSeal and Tisseel in dealing with vascular and collecting-system injury during partial nephrectomy., Materials and Methods: We performed an open right lower-pole partial nephrectomy on 15 large female pigs. The defect was repaired using standard open techniques (N = 5; controls), Tisseel only (N = 6; group I), or FloSeal followed by Tisseel (N = 4; group II). A Jackson-Pratt drain was placed. Nephrectomy and retrograde pyelography were performed at 1 week., Results: Operative times were shorter in both study groups, achieving statistical significance in group I (P = 0.008). Warm-ischemia times were significantly improved in both study groups (P = 0.029 and P = 0.00005 in groups I and II, respectively). Time to hemostasis was significantly shorter in group II only (P = 0.002) but approached significance in Group I as well (P = 0.09). Estimated blood loss was not significantly different from the controls in either group. When Tisseel was placed alone after hilar control, hematoma formation under the Tisseel was noted on release of the hilar clamp. After 1 week, there was one urinoma and three urine leaks in the control group. In group I, there was one urinoma and four urine leaks, and there was only one urine leak and no urinomas in group II. There were no hematomas in any of the groups., Conclusions: Tisseel alone is not adequate for either hemostasis or management of major collecting-system injury. FloSeal capped with Tisseel appears sufficient to control major vascular and collecting-system injuries without adjunctive surgical measures. A proposed technique for laparoscopic partial nephrectomy without reconstructive techniques is presented that warrants clinical study.

Objectives: To perform an analysis of currently available manufacturer data regarding the character of ureteroscope damage. The high costs associated with the repair of flexible and semirigid ureteroscopes are well documented. Increased knowledge of the etiology of ureteroscope damage should aid urologists in prolonging the lives of these delicate instruments., Methods: We requested data from the four major ureteroscope manufacturers (ACMI, Olympus America, Karl Storz, and Richard Wolf) on the types, speculated causes, costs, and frequency of ureteroscope damage. The results were tabulated in a blinded fashion and analyzed for trends. We then formulated guidelines that could be applied by practicing urologists., Results: For both flexible and semirigid ureteroscopes, the frequency of repair increased with decreasing ureteroscope diameter and increasing instrument length. The cost of the repair was generally greater for flexible ureteroscopes (mean 4597 dollars) than for semirigid ureteroscopes (mean 2437 dollars). The major causes of flexible ureteroscope damage were working channel damage from laser burn or instrument passage and extreme scope deflection with an indwelling instrument. The primary reasons for semirigid ureteroscope repair included overtorquing and improper handling in the operating room and during sterile processing., Conclusions: Urologists can minimize the repair costs of flexible and semirigid ureteroscopes by taking precautions to eliminate laser fiber-induced damage and by avoiding overdeflection. Improved storage and handling of these instruments is also necessary. Although small-diameter ureteroscopes are favorable because of their increased mobility and ease of passage, physician and staff awareness of their increased fragility is vital in maximizing the longevity of these commonly used instruments.

Objective: To present early experience in managing complex renal calculi using a combined ureteroscopic and percutaneous approach, as complex and branched renal calculi often require multiple access tracts during percutaneous nephrolithotomy (PNL), and the combined use of flexible ureteroscopy and PNL has the potential to reduce the inherent morbidity of several tracts., Patients and Methods: The study included seven patients (mean age 54 years) with multiple, branched, large-volume renal calculi suitable for management with PNL. Preoperative data, including patient demographics, stone location and stone surface area, were recorded. After informed consent, the patients underwent combined PNL and ureteroscopy in one session. Intraoperative data, including the location of PNL puncture sites, operative duration and complications, were analysed. Stone-free rates were determined by follow-up imaging at 3 months., Results: All patients had either two or more stones in separate locations in the collecting system, or staghorn stones involving multiple calyces. The mean stone burden was 666 mm(2). All patients had only one percutaneous access tract. The mean operative duration was 142 min and the mean blood loss 79 mL. Two patients had small residual stones (< 3 mm), that required ureteroscopic intervention as they failed to pass spontaneously by 3 months after the initial combined procedure. The convalescence was similar to that in our current PNL practice; imaging showed that five of the patients were stone-free., Conclusions: Combined PNL and ureteroscopic management can effectively reduce the number of percutaneous access tracts which would otherwise be required for managing complex and branched renal calculi, as stones in an unfavourable location relative to the access tract can be relocated and fragmented within easy reach of the single nephrostomy tract. This manoeuvre reduces potential patient morbidity and blood loss but with no significant effect on stone-free rates and operative durations.

Purpose: We provide a systematic assessment of the quality and accuracy of statistical reporting in the urology literature., Materials and Methods: All original research publications with adult human subjects in a single issue (August 2004) of 4 leading urology journals were identified for formal review. A standardized evaluation form was developed in consultation with an experienced biostatistician and subsequently tested. Two independent reviewers with at least 1 year of formal training in research design and biostatistics who were blinded to authors and institutions reviewed each article. Discrepancies were settled by consensus and/or adjudication by the biostatistician., Results: Of the 169 articles screened 97 met eligibility criteria for review. Cohort (43 of 97 or 44%) or cross-sectional (28 of 97 or 29%) designs comprised the majority of these studies. Only 10 randomized clinical trials (12.4%) were identified. Statistical tests were identified in 83 studies (93%). Overall 69 of 83 studies (71%) providing statistical comparisons had at least 1 statistical error, including using the wrong test for the data type in 28%, inappropriate use of a parametric test in 22% and failure to account for multiple comparisons in 65%. In studies applying multivariate analysis (29%) over fitting the model with too many variables was the most common statistical flaw (39%)., Conclusions: This formal review suggests that statistical methods are often used inappropriately in the urology literature, thereby, potentially undermining the validity of study results and conclusions. An effort to raise the awareness of appropriate statistical techniques through postgraduate education appears indicated.

Objectives: To evaluate the effect of ureteral access sheaths (UASs) on stone-free rates (SFRs) during ureteroscopic treatment of renal calculi. Several advantages of UASs during flexible ureteroscopy have been documented. However, no study has evaluated their impact on SFRs., Methods: We retrospectively reviewed all ureteroscopic cases for the management of renal stones performed at our Stone Center. Data were stratified according to the use or lack of use of the UAS. The groups were stratified by stone location within the kidney. Stone-free status was determined at 2 months postoperatively by either intravenous urography with tomograms or noncontrast renal computed tomography in patients with contrast allergies., Results: A total of 256 ureteroscopic procedures for the removal of renal calculi were performed between 1997 and 2003 (173 with UAS and 83 without). The groups were similar in age, sex, and stone burden. Stents were placed in nearly 80% of patients. The lower renal pole represented the most common presenting location. Stone displacement with a ureteroscopic basket for efficient fragmentation was necessary in 34%. The overall SFR in the UAS group and non-UAS group was 79% and 67%, respectively (P = 0.042). The SFRs were improved for calculi in all portions of the kidney., Conclusions: In addition to facilitating ureteroscopic access, reducing costs, and lowering intrarenal pressures, the results of the current study suggest that UASs improve SFRs during the management of renal calculi. It is now our current practice to use the UAS routinely during ureteroscopic treatment of renal and upper ureteral calculi.

Purpose: The optimal management of lower pole renal calculi is controversial. We compared shock wave lithotripsy (SWL) and ureteroscopy (URS) for the treatment of patients with small lower pole stones in a prospective, randomized, multicenter trial., Materials and Methods: A total of 78 patients with 1 cm or less isolated lower pole stones were randomized to SWL or URS. The primary outcome measure was stone-free rate on noncontrast computerized tomography at 3 months. Secondary outcome parameters were length of stay, complication rates, need for secondary procedures and patient derived quality of life measures., Results: A total of 67 patients randomized to SWL (32) or URS (35) completed treatment. The 2 groups were comparable with respect to age, sex, body mass index, side treated and stone surface area. Operative time was significantly shorter for SWL than URS (66 vs 90 minutes). At 3 months of followup 26 and 32 patients who underwent SWL and URS had radiographic followup that demonstrated a stone-free rate of 35% and 50%, respectively (p not significant). Intraoperative complications occurred in 1 SWL case (unable to target stone) and in 7 URS cases (failed access in 5 and perforation in 2), while postoperative complications occurred in 7 SWL and 7 URS cases. Patient derived quality of life measures favored SWL., Conclusions: This study failed to demonstrate a statistically significant difference in stone-free rates between SWL and URS for the treatment of small lower pole renal calculi. However, SWL was associated with greater patient acceptance and shorter convalescence.

Purpose: Nephrolithiasis disproportionately affects white patients. However, recent studies propose an increase in the incidence of stone disease in nonwhite populations. We compared the metabolic risk factors of ethnically disparate stone formers from the same geographic region., Materials and Methods: A retrospective review of 1,141 patients identified 98 (9%) nonwhite stone formers. Of these individuals 60 underwent a comprehensive metabolic evaluation, comprising 44 black, 8 Asian and 8 Hispanic patients. A similar sex and age matched group of 66 white stone forming patients were also identified for comparative analysis. Stone analyses were recorded when available. Urinary metabolic abnormalities were defined as low urine volume-urine volume less than 2,000 cc, gouty diathesis-pH 5.5 or less (normal level 5.5 to 6.5), hypercalciuria-calcium greater than 200 mg, hyperoxaluria-oxalate greater than 45 mg, hyperuricosuria-uric acid greater than 600 mg, hypocitraturia-citrate less than 600 mg and purine gluttony-sulfate greater than 20 mg., Results: The incidence of metabolic abnormalities was surprisingly similar between the white and nonwhite stone formers. Whites have a higher prevalence of hypercalciuria compared with nonwhites (67% vs 25%, respectively, p <0.01). This comparison persisted when the white group was compared with individual ethnic groups (25% in each group). Whites also displayed a higher mean urinary calcium level (233 mg) than their nonwhite counterparts overall (146 mg), specifically with respect to blacks (146 mg, p <0.01). Asians had higher urine volumes with respect to whites and blacks (p <0.01) and, therefore, a decreased prevalence of low urine volumes (37.5% vs 74.2% and 79.5%, respectively). Hypocitraturia, hyperuricosuria, hyperoxaluria, gouty diathesis and high sulfate levels were equally represented among all ethnic groups., Conclusions: Although there appears to be a predominance of stone disease among whites, all racial groups demonstrated a remarkable similarity in the incidence of underlying metabolic abnormalities. These results suggest that dietary and environmental factors may be as important as ethnicity in the etiology of stone disease.