Burden of Urolithiasis: Trends in Prevalence, Treatments, and Costs.

CONTEXT: The recent evolution of management options for urolithiasis has presented a unique dilemma for the modern urologist. A comprehensive understanding of epidemiological trends along with current provider preferences in treating urinary stones would be beneficial. OBJECTIVE: To review trends in the prevalence, treatments, and costs of urolithiasis worldwide. EVIDENCE ACQUISITION: A literature review was performed using the MEDLINE database, the Cochrane Library Central search facility, Web of Science, and Google Scholar between 1986 and 2016. Keywords used for the search were "urolithiasis" and "prevalence; treatment; and cost". EVIDENCE SYNTHESIS: The incidence and prevalence of urinary stones are rising around the world, including regions that have historically had low rates of urolithiasis. Common theories explaining this trend involve climate warming, dietary changes, and obesity. Shockwave lithotripsy (SWL) has been the preferred mode of treatment since its introduction in the 1980s. However, ureteroscopy (URS) has become increasingly popular for small stones regardless of location because of lower recurrence rates and costs. Developing countries have been slower to adopt URS technology and continue to use percutaneous nephrolithotomy at a steady rate. CONCLUSIONS: URS has recently challenged SWL as the treatment modality preferred for small upper urinary tract stones. In some cases it is less expensive but still highly effective. As the burden of stone disease increases worldwide, appropriate selection of stone removal therapies will continue to play an important role and will thus require further investigation. PATIENT SUMMARY: Urinary stones are becoming more prevalent. Recent advances in technology have improved the management of this disease and have decreased costs.

KIM-1 Is a Potential Urinary Biomarker of Obstruction: Results from a Prospective Cohort Study.

INTRODUCTION: Partial or complete obstruction of the urinary tract is a common and challenging urological condition that may occur in patients of any age. Serum creatinine is the most commonly used method to evaluate global renal function, although it has low sensitivity for early changes in the glomerular filtration rate or unilateral renal pathology. Hence, finding another measurable parameter that reflects the adaptation of the renal physiology to these circumstances is important. Several recent studies have assessed the use of new biomarkers of acute kidney injury (AKI), but the information among patients with stone disease and those with obstructive uropathy is limited. MATERIAL AND METHODS: A prospective cohort study was conducted to determine the urinary levels of kidney injury molecule-1 (KIM-1), Total and Monomeric neutrophil gelatinase-associated lipocalin (NGAL) in patients with hydronephrosis secondary to renal stone disease, congenital ureteropelvic junction obstruction or ureteral stricture. Comparison between patients with hydronephrosis and no hydronephrosis was carried out along with correlation analysis to detect factors associated with biomarker expression. RESULTS: Urinary levels of KIM-1 significantly decreased after hydronephrosis treatment in patients with unilateral obstruction (1.19 ng/mL vs 0.76 ng/mL creatinine, p = 0.002), additionally KIM-1 was significantly higher in patients with hydronephrosis compared to stone disease patients without radiological evidence of obstruction (1.19 vs 0.64, p = 0.006). Total and Monomeric NGAL showed a moderate correlation with the presence of leukocyturia. We found that a KIM-1 value of 0.735 ng/mg creatinine had a sensitivity of 75% and specificity of 67% to predict the presence of hydronephrosis in preoperative studies (95% CI 0.58-0.87, p = 0.006). CONCLUSION: Our results show that KIM-1 is a promising biomarker of subclinical AKI associated with hydronephrosis in urological patients. NGAL values were influenced by the presence of leukocyturia, limiting its usefulness in this population.

Perioperative characteristics of dogs undergoing open versus laparoscopic-assisted cystotomy for treatment of cystic calculi: 89 cases (2011-2015).

OBJECTIVE To compare perioperative characteristics of dogs with cystic calculi treated via open versus laparoscopic-assisted cystotomy (LAC). DESIGN Retrospective case series. ANIMALS 89 client-owned dogs that underwent open cystotomy (n = 39) or LAC (50). PROCEDURES Medical records of dogs that underwent cystotomy between 2011 and 2015 were reviewed. History, signalment, surgery date, results of physical examination, results of preoperative diagnostic testing, details of surgical treatment, duration of surgery, perioperative complications, treatment costs, and duration of hospitalization were recorded. RESULTS 5 of 50 (10%) dogs required conversion from LAC to open cystotomy (OC). There was no significant difference between the LAC (1/50) and OC (2/39) groups with regard to percentage of patients with incomplete removal of calculi. Duration of surgery was not significantly different between the LAC (median, 80 min; range, 35 to 145 min) and OC (median, 70 min; range, 45 to 120 min) groups. Postoperative duration of hospitalization was significantly shorter for dogs that underwent LAC (median, 24 hours; range, 12 to 48 hours) versus OC (median, 26 hours; range, 12 to 63 hours). Surgical and total procedural costs were significantly higher for patients undergoing LAC. CONCLUSIONS AND CLINICAL RELEVANCE Results suggested that LAC may be an acceptable minimally invasive technique for treatment of cystic calculi in dogs. Surgery times were similar to those for dogs undergoing OC; however, surgical and total procedural costs were higher. Further investigation is suggested to determine which patients may benefit from LAC versus traditional OC.

Natural History of Residual Fragments After Percutaneous Nephrolithotomy: Evaluation of Factors Related to Clinical Events and Intervention.

OBJECTIVE: To determine the natural history of residual fragments (RF) after percutaneous nephrolithotomy in long-term patient follow-up and to identify possible predictive factors for future intervention. MATERIALS AND METHODS: We assessed all patients from 2006 to 2013 with postoperative computed tomography scan revealing RF, who did not undergo second-look nephroscopy or immediate ancillary procedures, and with at least 12 months of clinical follow-up. We evaluated factors associated with clinical, radiological, and surgical outcomes. Kaplan-Meier curves were used to calculate the proportion of asymptomatic and treatment-free patients during follow-up. RESULTS: From 781 percutaneous nephrolithotomies performed, 202 patients underwent postoperative computed tomography scan and 44 patients with residual stones were included in the analysis. Mean follow-up was 57.9 months. A total of 24 patients (54.5%) developed at least 1 clinical outcome, and 32 (72.7%) patients had a surgical intervention. Only 4 patients had radiological evidence of stone passage. Multivariate analysis found that RF >4 mm and struvite or apatite stones were significant predictors for surgical intervention. The 5-year estimated probability to remain intervention free was 29%. CONCLUSION: Despite the size of the RF, the vast majority of patients required an intervention during long-term follow-up. We identified that RFs of diameter >4 mm associate with the need for a surgical therapy, but the rate of clinical events was not affected by the size or location of the stones. Struvite or apatite composition stones had an increased risk of intervention during follow-up. Spontaneous passage was an uncommon event in this cohort.

The Impact of Distraction on Laparoscopic Skills in Veterinary Medical Students.

OBJECTIVE: To investigate the impact of distraction on the performance of a simulator-based laparoscopic task in veterinary students. STUDY DESIGN: Prospective, randomized trial. SAMPLE POPULATION: Years 1-4 veterinary students (n=41). METHODS: Participants repeated a simulated laparoscopic peg transfer task to eliminate any learning effects and were subsequently randomized to receive either a cognitive (double-digit addition questions, n=21) or sensory distraction (dogs barking and anesthesia monitor alerts, n=20). The laparoscopic task scores were compared between baseline and in the presence and absence of each distraction. The number of addition questions attempted, and the number of questions answered correctly in 1 minute were compared between baseline and during a concurrent laparoscopic task. RESULTS: Baseline laparoscopic task scores were not significantly different between groups (P=.09). Laparoscopic task scores were significantly lower than baseline when performed with the cognitive distraction (P<.001) and significantly higher than baseline when performed with the sensory distraction (P=.005). Participants undergoing cognitive distraction attempted significantly fewer addition questions (P<.001) and answered significantly fewer addition questions correctly (P<.001) when a concurrent laparoscopic task was performed. CONCLUSION: Cognitive distraction had a negative impact on the performance of a laparoscopic task in this cohort of veterinary students, whereas sensory distraction had a positive effect.

Multicenter External Validation and Comparison of Stone Scoring Systems in Predicting Outcomes After Percutaneous Nephrolithotomy.

BACKGROUND AND PURPOSE: Several scoring systems have recently emerged to predict stone-free rate (SFR) and complications after percutaneous nephrolithotomy (PCNL). We aimed to compare the most commonly used scoring systems (Guy's stone score, S.T.O.N.E. nephrolithometry, and CROES nomogram), assess their predictive accuracy for SFR and other postoperative variables, and develop a risk group stratification based on these scoring systems. MATERIALS AND METHODS: We performed a retrospective review of patients who have had a PCNL at four academic institutions between 2006 and 2013. Primary outcome was SFR within 3 weeks of the surgery and secondary outcomes were operative time (OT), complications, and length of stay (LOS). We performed chi-squared, t-test, logistic, linear, and Poisson regressions, as well as receiver operating characteristics curve with area under the curve (AUC) calculation. RESULTS: We identified 586 patients eligible for analysis. Of these, 67.4% were stone free. Guy's, S.T.O.N.E., and CROES score were predictive of SFR on multivariable logistic regression (odds ratio [OR]: 1.398, 95% confidence interval [CI]: 1.056, 1.852, p = 0.019; OR: 1.417, 85% CI: 1.231, 1.631, p < 0.001; OR: 0.993, 95% CI: 0.988, 0.998, p = 0.004) and have similar predictive accuracy with AUCs of 0.629, 0.671, and 0.646, respectively. On multivariable linear regression, only S.T.O.N.E. was an independent predictor of longer OT (ß = 14.556, 95% CI: 12.453, 16.660, p < 0.001). None of the scores were independent predictors of postoperative complications or a longer LOS. Poisson regression allowed for risk group stratification and showed the S.T.O.N.E. score and CROES nomogram to have the most distinct risk groups. CONCLUSIONS: The three evaluated scoring systems have similar predictive accuracy of SFR. S.T.O.N.E. has additional value in predicting OT. Risk group stratification can be used for patient counseling. Further research is needed to identify whether or not any is superior to the others with regard to clinical usefulness and predictive accuracy.

The Effect of Renal Cysts on the Fragmentation of Renal Stones During Shockwave Lithotripsy: A Comparative In Vitro Study.

PURPOSE: To assess the potential effect of simple renal cysts (SRC) on stone fragmentation during shockwave lithotripsy (SWL) in an in vitro model. MATERIALS AND METHODS: The in vitro model was constructed using 10% ordnance gelatin (OG). Models were created to mimic four scenarios: Model A-with an air-filled cavity (suboptimal for stone fragmentation); model B-without a cavity (normal anatomy); model C-with a 3-cm serum filled cavity (to represent a small SRC); model D-with a 4-cm serum filled cavity (to represent a larger SRC). SWL was applied to 24 standardized phantom stones (weight of 2±0.1 g) in each model using a standardized protocol. Stone fragments were retrieved, then dried overnight at room air temperature. Fragmentation coefficient (FC) was calculated for each stone, for fragments<4 mm and <2 mm. RESULTS: The OG in vitro model was robust enough for the proposed research. There was no fragmentation evident in model A as expected. The mean FC was 29.7 (±20.5) and 39.7 (±23.7) for <4 mm fragments (P=0.069) and 7.6 (±4.1) and 10.6 (±6.7) for <2 mm fragments (P=0.047), for noncystic and cystic models, respectively. The mean FC was 29.7 (±20.5), 38.8 (±26.2) and 40.7 (±21.3) for <4 mm fragments (P=0.213) and 7.6 (±4.1), 11.1 (±8) and 10.2 (±5.3) for <2 mm fragments (P=0.138), for models B, C, and D, respectively. CONCLUSION: Our in vitro experiment confirms better stone fragmentation associated with SWL in the presence of adjacent SRC.

Risk Factors for Postoperative Complications of Percutaneous Nephrolithotomy at a Tertiary Referral Center.

PURPOSE: We sought to describe and evaluate the complications related to percutaneous nephrolithotomy and identify risk factors of morbidity according to the modified Clavien scoring system. We also sought to specify which perioperative factors are associated with minor and major complications. MATERIALS AND METHODS: We retrospectively analyzed data on patients who underwent percutaneous nephrolithotomy from 1990 to 2013. Descriptive statistics were used to analyze patient characteristics, medical comorbidities and perioperative features. Complications were categorized according to the Clavien score for percutaneous nephrolithotomy. The Mann-Whitney and Fisher exact tests were used as appropriate. Logistic regression analysis was performed to look for prognostic factors associated with major complications. RESULTS: A total of 2,318 surgeries were evaluated. Mean age of the population was 53.7 years. The stone-free rate at hospital discharge was 81.6%. The overall complication rate was 18.3%. Two deaths occurred. Patients with any postoperative complications were older, had more comorbidities, were more likely to have staghorn calculi and had longer operative time and hospital stay on univariate analysis (p<0.05). Age 55 years or older and upper pole access were independent predictors of major complications on multivariate analysis. Other factors such as a history of urinary tract infections, body mass index, stone composition, previous percutaneous nephrolithotomy and multiple tracts were not associated with a major complication. CONCLUSIONS: At our center percutaneous nephrolithotomy is an excellent option for complex kidney stone management with a low overall complication rate. Older patient age and upper pole access are significantly associated with an increased risk of a major complication.

A comparison of outcomes after percutaneous nephrolithotomy in children and adults: a matched cohort study.

INTRODUCTION: Percutaneous nephrolithotomy (PCNL) has surpassed open stone surgery as the operation of choice for large and complex stone burdens (figure). Although the procedure was developed in adults, its principles have been extrapolated to children. There is a paucity of literature comparing outcomes of PCNL in adults and children for similar stone burdens. OBJECTIVE: The purpose of this study was to evaluate outcomes following PCNL among children and adults with similar stone burdens. PATIENTS AND METHODS: Data on patient characteristics and outcomes for 2196 consecutive patients undergoing PCNL at a single institution were collected prospectively from January 1992 to July 2013. Thirty-one pediatric patients undergoing 39 PCNLs were identified. Each pediatric PCNL was matched in a ratio of 1:4 to adult PCNLs by year of surgery and stone burden characteristics (staghorn, partial staghorn, number of stones). All PCNLs were performed by two fellowship-trained endourologists who operate on both adult and pediatric patients. Ultrasonic lithotripsy was used primarily. The primary outcome measure was stone-free rate (SFR) at hospital discharge. Secondary outcomes included the need for second-look nephroscopy, length of hospital stay, complication rate, and blood transfusion rate. The Student t test was used for continuous variables and the Fisher exact for categorical variables. RESULTS: The median age for the pediatric group was 13.9 ± 4.30 years and for the adult group was 55.4 ± 15.1 years. Pediatric patients tended to present with metabolic stones, with no difference in rates of infection stones. No difference was found in SFR at time of hospital discharge (86.1% vs. 86.4%, p = 0.2). More pediatric patients required a second access tract than adult patients (15.4% vs. 4.52%, p = 0.02). There was no significant difference in the need for second-look nephroscopy, length of stay, or complication rates (overall and by Clavien classification subgroup) between both groups. The rates of blood transfusion were low in both groups (0% vs. 0.6%, p = 0.80). DISCUSSION: There was no difference in primary and secondary outcomes among children compared with adults undergoing PCNL in our study. The outcomes reported in this study were similar to published literature. A limitation of this study is the low number of pediatric patients. However, it is unique to have a single-center study that compares PCNL outcomes in both adult and pediatric patient and accounts for stone burden characteristics. CONCLUSIONS: Although principles of PCNL were developed in adults, this study affirms the safety and efficacy of PCNL in both pediatric and adult patients.

The use of internal stents in chronic ureteral obstruction.

PURPOSE: Despite the lack of a well delineated definition, chronic ureteral obstruction imposes significant quality of life loss, increased pathological morbidity and risk of mortality as well as substantial economic burden. Ureteral stenting serves as an important therapeutic option to alleviate obstruction. Thus, we assessed the recently published literature on chronic ureteral obstruction; treatment options; types, benefits and shortcomings of current ureteral stents; as well as outcomes and complications of chronic ureteral stenting, with the goal of providing concise management guidelines. MATERIALS AND METHODS: A systemic literature review was performed on Embase™, PubMed®, Cochrane Controlled Trials Register and Google Scholar™ on ureteral obstruction and internal ureteral stents. Relevant reviews, original research articles and their cited references were examined, and a synopsis of original data was generated on a clinically oriented basis. RESULTS: Chronic ureteral obstruction can be classified into compression that is either intrinsic or extrinsic to the ureteral wall, or obstruction that is of a benign or malignant origin. Patients with malignant ureteral obstruction generally have a poor prognosis and are often difficult to treat. The aim of stenting is to adequately drain the upper urinary tracts while minimizing hospitalization and the negative impact on quality of life. Facing the challenge of chronic ureteral obstruction, novel stents with new compositions, materials, coatings and designs have been developed. Metallic stents are emerging as efficacious and financially viable alternatives. Early stent related complications include iatrogenic injury, stent migration or patient discomfort, while late complications include infection, difficulties with stent exchange, hardware malfunction, infection and stent encrustation. CONCLUSIONS: Stenting in chronic ureteral obstruction is a complex and challenging problem. Much work is being done in this area and many options are being explored.

Percutaneous nephrolithotomy in patients with urinary tract abnormalities.

BACKGROUND AND PURPOSE: Patients with urinary tract abnormalities are at an increased risk of stone formation. Percutaneous nephrolithotomy (PCNL) plays an important role in the treatment of this patient population; however, outcomes are less well defined compared with patients with normal urinary tract anatomy. Our objective was to evaluate the influence of urinary tract abnormalities on intraoperative and postoperative outcomes with PCNL. PATIENTS AND METHODS: We report on a single-center prospective database of 2284 consecutive PCNLs in 1935 patients from 1990 to 2012. For the purposes of this analysis, patients were categorized by the presence or absence of a urinary tract abnormality. Multivariable analyses were used to identify independent predictors of the length of hospital stay, operative time, complications, and residual stones at discharge and 3 months. RESULTS: A urinary tract abnormality was present in 14.4% (n=330) of the cohort. On univariable analysis, patients with urinary tract abnormalities were more likely to present with urinary tract infection (28% vs 19%, P<0.001) and less likely to present with hematuria (13% vs 19%, P<0.02). On multivariable regression, a urinary tract abnormality was predictive of residual stone at discharge, need for a secondary procedure, but did not increase the risk of residual stone at 3 months or the development of complications. Operative time and hospital stay were only moderately prolonged. CONCLUSION: Patients with urinary tract abnormalities who undergo PCNL have a higher risk of residual stones at discharge and need for secondary procedures, but comparable complication rates, operative time, and hospital stay.

Standardizing the reporting of percutaneous nephrolithotomy complications.

Accurate reporting of complications is an essential component to critical appraisal and innovation in surgery and specifically with percutaneous nephrolithotomy (PCNL). We review the evolution of complication reporting for PCNL and suggest future directions for innovation. A selective review was carried out using Pubmed. Key search terms and their combinations included percutaneous, anatrophic, nephrolithotomy, PCNL, complications, Clavien, Martin score, bleeding, bowel injury, perforation, fever, sepsis. The references from relevant papers and reviews as well as AUA and EAU guidelines were also scanned for inclusion. PCNL has become the procedure of choice for large renal stones owing to decreased morbidity over alternative procedures. Both common and rare complications have been described in large case series, small randomized controlled trials, and case reports in an unstandardized form. Although these reports have provided an informative starting point, a standardized complication reporting methodology is necessary to enable appropriate comparisons between institutions, time periods, or innovations in technique. The Clavien-Dindo grading system has become widely accepted in urology and has facilitated the study of PCNL complications. Future research should focus on adaptions of this system to render it more comprehensive and applicable to PCNL.

The Post-Ureteroscopic Lesion Scale (PULS): a multicenter video-based evaluation of inter-rater reliability.

PURPOSE: The Post-Ureteroscopic Lesion Scale (PULS) offers a simple grading system for the description of ureteral lesions after ureteroscopy. In this article, we present the results of a video-based multicenter evaluation of the inter-rater reliability of clinically important PULS grades 0-3. METHODS: Video sequences at the end of ureteroscopy (final passage) were recorded for 100 consecutive patients at a single institution and assessed by experienced urologists (n = 20) and senior residents (n = 17) at 19 international centers. The cohort included only patients with lesions grades 0-3 (with grades 2 and 3 subsumed as 2 + since distinction is defined by an extravasation of contrast medium in fluoroscopy). The gradings were evaluated for inter-rater reliability and in terms of simplicity, validity, comprehensibility, reproducibility, and usefulness. RESULTS: Overall, inter-rater reliability was high (Kendall's W = 0.69, p < 0.001) and was comparable between specialists (Kendall's W = 0.69, p < 0.001) and residents (Kendall's W = 0.71, p < 0.001). The matched ratings showed grade 0 in 43.0 % of patients and grades 1 or 2 + in 44.0 and 13.0 % of patients, respectively. Results of the questionnaires indicated a high degree of acceptance, with an overall rating of 1.76 (1.64-1.93 for different items, scale 1-6). CONCLUSIONS: Inter-rater reliability of the endoscopically assessable PULS was high among urologists with different levels of experience in different countries worldwide. The validated PULS system may be used for standardized reporting of ureteral lesions/injuries after ureteroscopy. In addition, PULS will enable more selective standardization of indications for postoperative DJ stenting based on the randomized controlled trials.

Does using comprehensive preoperative bowel preparation offer any advantage for urinary diversion using ileum? A meta-analysis.

PURPOSE: The aim of this study was to compare the efficacy of comprehensive bowel preparation to that of limited bowel preparation in prevention of postoperative complications in elective urinary diversion surgery by using ileum. METHODS: Literature search of PubMed, EMBASE and the Cochrane Library was done to identify randomized controlled trials (RCTs) and cohort studies involving comparison of postoperative complications after comprehensive bowel preparation and limited bowel preparation. A meta-analysis was carried out to distinguish overall differences between the two groups. RESULTS: Our literature search yielded two randomized controlled trials and two cohort studies, involving a total of 346 patients, which met our inclusion criteria. There was no significant difference between the comprehensive bowel preparation and limited bowel preparation in wound infection [relative risk (RR) 95 % confidence interval (CI), 1.05(0.46-2.40); P = 0.86], mortality [RR 95 % CI, 1.06 (0.32-3.55); P = 0.76], ileus [RR 95 % CI, 0.86 (0.37, 2.00); P = 0.40], sepsis [RR 95 % CI, 0.71 (0.20, 2.52); P = 0.78], anastomotic leakage [RR 95 % CI, 0.81 (0.15, 4.21); P = 0.83], wound dehiscence [RR 95 % CI, 0.92 (0.40, 2.13); P = 0.67], peritonitis [RR 95 % CI, 0.64 (0.08, 5.10); P = 0.63] or fistula [RR 95 % CI, 0.71 (0.18,2.75); P = 0.63]. CONCLUSIONS: The limited evidence available demonstrated that the use of comprehensive bowel preparation for urinary diversion surgery using ileum does not offer any significant advantage over limited bowel preparation. Future work should target more high-quality RCTs to confirm this.

Percutaneous nephrolithotripsy in patients with urinary diversions: a case-control comparison of perioperative outcomes.

PURPOSE: To compare the operative techniques and perioperative outcomes of patients with urinary intestinal diversions undergoing percutaneous nephrolithotripsy (PCNL), to a control cohort of patients without diversions. PATIENTS AND METHODS: The medical records of all patients who were treated with PCNL from 1990 to 2009 were retrospectively reviewed. Each urinary diversion patient's first PCNL was age-matched with four controls who were undergoing PCNL. The perioperative outcomes were compared between the diversion and control cohorts. RESULTS: Twenty-five patients with a urinary diversion who had undergone 33 PCNLs were identified. The mean age was 49.3 (8-85) years for the diversion group and 48.9 (4-84) for the control group. Urinary tract infection (64% vs 15% patients, P<0.0001), neurologic disease (64% vs 2%, P<0.0001), previous procedure for the same calculus (24% vs 4%, P=0.0004), urinary tract abnormalities (56% vs 14%, P<0.0001), solitary kidney (20% vs 3%, P=0.0081), and struvite stones (80% vs 12.5%, P=0.0006) were more commonly observed in the diversion group. Percutaneous access gained by a radiologist (40% vs 0%, P<0.0001), second-look nephroscopy (36% vs 16%, P=0.0466), and an increase in the frequency of fever or sepsis (8% vs 0%, P=0.0387) were identified more frequently in the diversion group. CONCLUSIONS: Patients with upper tract calculi and urinary diversions are challenging to the endourologist because of anatomic factors that can make percutaneous access more difficult; ultrasonography-guided access can be helpful in this setting. Patients with urinary diversions can be treated as safely and effectively by PCNL as nondiverted patients.

Percutaneous nephrolithotomy of caliceal diverticular calculi: a single center experience.

BACKGROUND AND PURPOSE: Caliceal diverticula are rare renal anomalies present in approximately 0.6% of the population. They are associated with calculi in 50% of cases. Therapeutic options include several minimally invasive techniques. We report a retrospective review of outcomes and complications from our series of patients who were treated with a percutaneous approach. PATIENTS AND METHODS: A database of outcomes related to percutaneous nephrolithotomy (PCNL) has been maintained at our institution since 1992. Data on all patients with caliceal diverticular stones who underwent PCNL during a 17-year period from 1992 to 2009 were reviewed retrospectively. Our preferred approach to PCNL in these patients is to puncture directly into the diverticulum and to try to advance a guidewire through the infundibular neck. In cases where the caliceal neck could not be intubated, we performed a transdiverticular approach with creation of a neoinfundibulum as a salvage procedure. We evaluated the two techniques with regard to stone-free rates and early postoperative complications. RESULTS: Seventy-six procedures were performed. The mean age was 43 years (range 17-72 y). The mean stone area was 583 mm(2). The surgical approach was direct puncture in 47, transdiverticular in 20, retrograde in 8, and unknown in 1 patient. Eight patients underwent lining fulguration. The average duration of surgery was 75 minutes (23-169 min) with an average hospital stay of 4.7 days. There were a total of 23 complications, of which 11 necessitated additional intervention. The overall stone-free rates were 77% and 89% for direct puncture and transdiverticular approaches, respectively. CONCLUSIONS: The percutaneous management of caliceal diverticular calculi is highly effective and can be accomplished with low morbidity.

Randomized controlled, multicentre clinical trial comparing a dual-probe ultrasonic lithotrite with a single-probe lithotrite for percutaneous nephrolithotomy.

OBJECTIVES: • To compare the Cyberwand (Gyrus/ACMI, Southborough, MA, USA), a dual-probe ultrasonic lithotrite, with a single-probe ultrasonic lithotrite. • The Cyberwand incorporates coaxial high- and low-frequency ultrasonic probes that work synergistically. PATIENTS AND METHODS: • An institutional review board-approved, multicentre, randomized controlled trial to compare the Cyberwand to the Olympus LUS-II (Olympus America, Inc., Melville, NY, USA) single-probe lithotrite was performed. • Patients undergoing a percutaneous nephrolithotomy (PCNL) with a target stone > 2 cm in diameter were eligible for the study. • The primary outcome was the time to removal of the targeted stone. RESULTS: • A total of 57 PCNLs were performed after randomization: 25 Cyberwand and 32 LUS-II. • There was no difference (P > 0.05) observed between the two devices for target stone surface area (Cyberwand 526.6 cm³ vs LUS-II 540.1 cm³), time to clearance of target stone (Cyberwand 15.8 min vs LUS-II 14.2 min) and target stone clearance rate (Cyberwand 61.9 mm²/min vs LUS-II 75.8 mm²/min). • Of the patients with stone analysis, hard stones (calcium oxalate monohydrate, brushite and cystine) were noted in 14 (56.0%) of the 25 Cyberwand and 18 (62.1%) of the 29 LUS-II patients. • Fifteen of the 25 (60.0%) Cyberwand and 20 of the 32 (62.5%) LUS-II patients were stone-free after the initial PCNL. • Those patients not rendered stone-free went on to receive a secondary PCNL. • Device malfunction occurred in eight of 25(32.0%) Cyberwand and five of 32 (15.6%) LUS II patients. • Complications were similar in both treatment groups. CONCLUSION: • No appreciable difference between the dual-probe Cyberwand and the standard ultrasonic Olympus LUS-II lithotrites can be identified.

Assessment of hydrodissection, holmium:YAG laser vaporization of renal tissue, and both combined to facilitate laparoscopic partial nephrectomy in porcine model.

OBJECTIVES: To evaluate the modalities of electrocautery, holmium:yttrium-aluminum-garnet (YAG) laser, hydrodissection, and combined holmium:YAG laser with hydrodissection applied to laparoscopic partial nephrectomy (LPN) in a porcine model. METHODS: A total of 16 Yorkshire pigs were divided into 4 equal groups (electrocautery, hydrodissection, holmium:YAG laser, and combined hydrodissection/holmium:YAG laser) and underwent unilateral LPN. The total operative time, partial nephrectomy time, hemostasis modality, and intraoperative complications were recorded. The pre- and postoperative hemoglobin was measured. Abdominal computed tomography was performed 2 weeks postoperatively. Representative specimens from each arm were examined for histologic findings. RESULTS: The mean total operative time and the time to perform partial nephrectomy was lower for the combined hydrodissection/holmium:YAG laser arm (66 minutes and 13 minutes, respectively) compared with the electrocautery arm (93 and 30 minutes, respectively), holmium:YAG laser-only arm (77 and 19 minutes, respectively), and hydrodissection-only arm (129 and 35 minutes, respectively). The mean decrease in hemoglobin was the least for the combined hydrodissection/holmium:YAG laser arm (5.3 g/L) followed by the holmium:YAG-only (15.3 g/L), hydrodissection-only (16.8 g/L), and electrocautery (35.5 g/L) arms, respectively. The histologic examination demonstrated an increased depth of tissue injury in the electrocautery arm. CONCLUSIONS: In a porcine model, the combined use of the hydrodissection/holmium:YAG laser to perform LPN had the shortest operative time and the lowest decrease in hemoglobin and appears to warrant additional clinical evaluation in human trials for LPN.

A novel drug eluting ureteral stent: a prospective, randomized, multicenter clinical trial to evaluate the safety and effectiveness of a ketorolac loaded ureteral stent.

PURPOSE: We evaluated the short-term safety and efficacy of a ketorolac loaded ureteral stent compared to a standard stent (control). MATERIALS AND METHODS: In this prospective, multicenter, double-blind study patients were randomized 1:1 to ketorolac loaded or control stents after ureteroscopy. The primary end point was an intervention for pain defined as unscheduled physician contact, change in pain medication or early stent removal. Secondary end points included medication use and pain visual analog score. A total of 20 patients underwent serum safety testing for ketorolac levels. RESULTS: None of the safety cohort had detectable serum ketorolac levels. Among the 276 patients there was no difference in primary (9.0% ketorolac loaded vs 7.0% control, p = 0.66) or secondary (22.6% ketorolac loaded vs 25.2% control, p = 0.67) intervention rates. Mean pain pill count at day 3 was lower in the ketorolac loaded stent group than in the control group (p <0.05). A higher number (p = 0.057) of patients with ketorolac loaded (32%) stents used no or limited pain medications compared to controls (22%). A higher number of male patients with ketorolac loaded stents used no pain medication on days 3 and 4 compared to female patients with ketorolac loaded stents, and male and female control patients (p <0.05). CONCLUSIONS: The overall safety of the ketorolac loaded stent was confirmed. Although there was no significant difference in primary or secondary intervention rates, a trend toward a treatment benefit was noted for patients receiving drug loaded stents. Specifically young male patients appeared to require less pain medication when the ketorolac loaded stent was used. Future studies with higher drug concentrations or alternative drug eluting stents may prove beneficial.