Renato N. Pedro

A pilot study on the early use of the vacuum erection device after radical retropubic prostatectomy

To evaluate the effect of the early use of the vacuum erection device (VED) on erectile dysfunction (ED) and penile shortening after radical retropubic prostatectomy (RP), as these are important concerns for men choosing among treatment alternatives for localized prostate cancer.

ALFUZOSIN STONE EXPULSION THERAPY FOR DISTAL URETERAL CALCULI: A DOUBLE-BLIND PLACEBO- CONTROLLED STUDY

PURPOSE We evaluated the efficacy of alfuzosin as medical expulsive therapy for distal ureteral stone passage. MATERIALS AND METHODS A total of 76 patients with a distal ureteral calculus provided consent for the study. Patients were randomized between placebo and study medication, and investigators and patients were blinded to the randomization scheme. Followup was done on a weekly basis and continued until the patient was rendered stone-free. The patient blood pressure, discomfort level, stone position on imaging, number of remaining pills and any adverse events were assessed. Statistical analysis was performed with the Student t test with p <0.05 considered significant. RESULTS The overall spontaneous stone passage rate was 75%, including 77.1% for placebo and 73.5% for alfuzosin (p = 0.83). Mean +/- SD time needed to pass the stone was 8.54 +/- 6.99 days for placebo vs 5.19 +/- 4.82 days for alfuzosin. (p = 0.003). There was no difference in the size or volume of stones that passed spontaneously between the placebo and alfuzosin arms, as measured on baseline computerized tomography (4.08 +/- 1.17 and 3.83 +/- 0.95 mm, p = 0.46) and by a digital caliper after stone expulsion (3.86 +/- 1.76 and 3.91 +/- 1.06 mm, respectively, p = 0.57). When comparing the improvement from the baseline pain score, the alfuzosin arm experienced a greater decrease in pain score in the days after the initial emergency department visit to the date of stone passage (p = 0.0005). CONCLUSIONS Alfuzosin improves the patient discomfort associated with stone passage and decreases the time to distal ureteral stone passage but it does not increase the rate of spontaneous stone passage.

Alfuzosin to Relieve Ureteral Stent Discomfort: A Prospective, Randomized, Placebo Controlled Study

PURPOSE We assessed the impact of alfuzosin on ureteral stent discomfort. MATERIALS AND METHODS A total of 66 patients scheduled for unilateral retrograde ureteroscopy with stent placement provided consent for the study. Patients were randomized between placebo and the study medication, and investigators and patients were blinded to the randomization scheme. To evaluate pain and urinary symptoms patients were asked to complete the Ureteral Stent Symptom Questionnaire (Stone Management Unit, Southmead Hospital, Westbury-on-Trym, United Kingdom) before ureteroscopy and 3 days after the procedure to minimize the confounding impact of procedural discomfort due to surgery. Patients were also asked to maintain a use log of pain medication each day that the ureteral stent was in place. Procedure outcome and complications were recorded, as were patient study medication use and vital health information before the procedure and at the time of stent removal. Statistical analysis was performed using the Student t, chi-square and Wilcoxon rank sum tests, as appropriate, with p <0.05 considered significant. RESULTS Of 66 patients who provided consent 55 successfully completed the study. In 3 of the 11 failed cases surgery was not done due to spontaneous stone passage, surgery was performed in 3 but no ureteral stent was placed, 4 were excluded from study after obtaining consent due to exclusion criteria and 1 was voluntarily removed from study after obtaining consent but before surgery. Regarding stent type, procedure complications and baseline questionnaire results there were no significant differences between the placebo and alfuzosin arms. When comparing post-procedure questionnaire results, patients in the alfuzosin arm reported less overall pain in the kidney/back/loin area and less pain in the kidney area while passing urine (p = 0.017 and 0.007, respectively). Men in the alfuzosin arm also reported a lesser incidence of excessive urination (p = 0.040). When comparing changes from baseline questionnaire results, the alfuzosin arm experienced a decrease in kidney pain during sleep (p = 0.017), less frequent use of painkillers to control kidney pain (p = 0.020) and a decrease in how much kidney associated pain interfered with life (p = 0.045). There was no significant difference in the amount of narcotics used per day, as reported in patient medication logs. CONCLUSIONS Alfuzosin improves the patient discomfort associated with ureteral stents by decreasing urinary symptoms and kidney pain but it does not affect the amount of narcotics that patients use while the stent is in place.

Durability of the Next-generation Flexible Fiberoptic Ureteroscopes: A Randomized Prospective Multi-institutional Clinical Trial

OBJECTIVES To evaluate the durability of 4 next-generation flexible ureteroscopes in a randomized, multi-institutional, prospective study. METHODS Patients at 3 institutions were randomized to 1 of 4 flexible ureteroscopes: the Wolf Viper, Olympus URF-P5, Gyrus-ACMI DUR-8 Elite (DUR-8E), and Stryker FlexVision U-500. Each center used 1 scope from each manufacturer until it needed major repair (primary endpoint). Intraoperative data included total time of use, number of scope insertions through an access sheath, working time in the lower pole, number of insertions and total time for accessory instrumentation in the working channel, number of laser insertions through the working channel, and total laser energy used. RESULTS A total of 175 patients were randomized. The DUR-8E experienced early catastrophic failure (< or = 10 cases) at all 3 sites; however, this also occurred at 1 site each for the Stryker and Wolf scopes. The DUR-8E required major repair after the fewest average number of cases (5.3), the lowest average total time of usage (108 minutes), the fewest insertions through an access sheath (20.3), the shortest duration of laser firing (31.3 minutes), and the shortest instrument in the working channel time (224.7 minutes). As such, due to variation in durability within manufacturers, no differences could be demonstrated. Visibility ratings for the Wolf iper were significantly better than the DUR-8E (P = .034) and the Flexvision (P = .038). CONCLUSIONS The Wolf Viper, Olympus URF-P5, and Stryker Flexvision U-500 flexible ureteroscopes seem comparable with regard to durability. However, larger prospective registry-based studies are needed to document significant differences between them.

Roux-en-Y Gastric Bypass is Associated with Early Increased Risk Factors for Development of Calcium Oxalate Nephrolithiasis

BACKGROUND Patients treated for obesity with jejunoileal bypass (JIB) experienced a marked increased risk of hyperoxaluria, nephrolithiasis, and oxalate nephropathy developing. Jejunoileal bypass has been abandoned and replaced with other options, including Roux-en-Y gastric bypass (RYGB). Changes in urinary lithogenic risk factors after RYGB are currently unknown. Our purpose was to determine whether RYGB is associated with elevated risk of developing calcium oxalate stone formation through increased urinary oxalate excretion and relative supersaturation of calcium oxalate. STUDY DESIGN A prospective longitudinal cohort study of 24 morbidly obese adults (9 men and 15 women) recruited from a university-based bariatric surgery clinic scheduled to undergo RYGB between December 2005 and April 2007. Patients provided 24-hour urine collections for analysis 7 days before and 90 days after operation. Primary outcomes were changes in 24-hour urinary oxalate excretion and relative supersaturation of calcium oxalate from baseline to 3 months post-RYGB. RESULTS Compared with their baseline, patients undergoing RYGB had increased urinary oxalate excretion (31 +/- 10 mg/d versus 41 +/- 18 mg/d; p = 0.026) and relative supersaturation of calcium oxalate (1.73 +/- 0.81 versus 3.47 +/- 2.59; p = 0.030) 3 months post-RYGB in six patients (25%). De novo hyperoxaluria developed. There were no preoperative patient characteristics predictive of development of de novo hyperoxaluria or the magnitude of change of daily oxalate excretion. CONCLUSIONS This prospective study indicates that RYGB is associated with an earlier increase in urinary oxalate excretion and relative supersaturation of calcium oxalate than previously reported. Additional studies are needed to determine longterm post-RYGB changes in urinary oxalate excretion and identify patients that might be at risk for hyperoxaluria developing.

Hyperoxaluria Is a Long-Term Consequence of Roux-en-Y Gastric Bypass: A 2-Year Prospective Longitudinal Study

BACKGROUND Recent studies suggest that patients undergoing Roux-en-Y gastric bypass (RYGB) for morbid obesity are at risk for hyperoxaluria, nephrolithiasis, and oxalate nephropathy. Our objective was to conduct a long-term prospective longitudinal study to establish the incidence, clinical progression, and severity of hyperoxaluria after RYGB. STUDY DESIGN Patients undergoing RYGB between December 2005 and April 2007 provided 24-hour urine collections for comprehensive stone risk analysis 1 week before and 3 months and 1 and 2 years after surgery. Primary outcomes were changes in 24-hour urinary oxalate excretion and relative supersaturation of calcium oxalate from baseline to 2 years post-RYGB. RESULTS The cohort consisted of 21 patients, including 5 (24%) men and 16 (76%) women. Mean preoperative age and body mass index (calculated as kg/m(2)) were 48.2 +/- 10.5 years (range 25 to 64 years) and 50.5 +/- 9.1 (range 39.7 to 66.6), respectively. Urinary oxalate excretion increased significantly after RYGB (33 +/- 9 mg/day versus 63 +/- 29 mg/day; p <or= 0.001). De novo hyperoxaluria developed in 11 (52%) patients. Increasing age at the time of surgery was predictive of de novo hyperoxaluria developing (odds ratio = 1.162; 95% CI, 1.002-1.347; p = 0.046). The percentage of patients with hypocitraturia increased from 10% at baseline to 48% at 2 years. The relative supersaturation of calcium oxalate was unchanged (1.73 +/- 0.67 versus 2.20 +/- 2.07; p = 0.27). CONCLUSIONS RYGB is associated with a long-term increase in urinary oxalate excretion and decrease in urinary citrate excretion. Although calcium oxalate relative supersaturation increases early in the postoperative period, this returns to baseline with long-term follow-up. These data suggest that patients who have undergone RYGB are at risk for oxalate nephropathy developing.

Lithogenic Risk Factors in the Morbidly Obese Population

PURPOSE To our knowledge baseline lithogenic risk factors in the morbidly obese population are currently unknown. Prior studies evaluated known stone formers and correlated risk with increasing body mass index. We describe risk factors for urinary stone formation in a group of unselected morbidly obese patients. MATERIALS AND METHODS Patients scheduled for gastric bypass provided a 24-hour urine collection before surgery. Patient demographics, medications and supplement consumption were recorded. A dietary intake diary was converted into daily kcal, Ca, Na and protein consumption. Differences between groups based on gender, history of diabetes or nephrolithiasis, diuretic use and Ca supplementation were evaluated. Correlation of stone risk parameters with body mass index was evaluated. RESULTS A total of 45 patients provided samples for analysis. Mean +/- SD body mass index was 49.5 +/- 9.1 kg/m(2) and mean age was 47.0 +/- 10.5 years. Overall 97.8% of patients had at least 1 lithogenic risk factor identified. Low urinary volume was the most common abnormality, affecting 71.1% of patients. Male patients excreted significantly more Ox (p = 0.0014), Na (p = 0.020), PO(4) (p = 0.0083) and SO(4) (p = 0.0014) than females. Patients with a history of nephrolithiasis excreted significantly more oxalate (p = 0.018) and had higher relative Na urate supersaturation (p = 0.00093) than nonstone formers. Hydrochlorothiazide use was associated with significantly increased Na urate relative supersaturation (p = 0.0097). Increasing body mass index was inversely associated with Mg (r = -0.38, p = 0.01) and brushite (r = -0.30, p = 0.04). CONCLUSIONS Of our cohort of morbidly obese patients 98% had at least 1 lithogenic risk factor identified on 24-hour urine collection. This study identified a high urinary stone risk in the morbidly obese and suggests possible avenues for dietary and/or pharmacological preventive measures. Future studies will determine how bariatric surgery alters these risk factors.

Systematic Evaluation of Ureteral Occlusion Devices: Insertion, Deployment, Stone Migration, and Extraction

OBJECTIVES To compare 4 ureteral occlusion devices in terms of insertion force, maneuverability, radial dilation and extraction forces, ability to prevent stone migration, and tip stiffness. METHODS The devices tested were the PercSys Accordion, Microvasive Stone Cone (7 and 10 mm), and Cook N-Trap. Using a ureteral model with an artificial stone in place, the insertion force, number of attempts, and time to pass the impacted stone were measured. Using a Teflon block model, radial dilation and extraction and axial extraction force were measured with a load cell. Holmium lithotripsy was performed in the ureteral model with a canine stone in place to test the ability of the devices to prevent stone migration. In a similar model, the force applied to retrieve the canine stone was measured. The stiffness of the tip was measured as the force to compress a 5-mm length of the tip in a clamp-clamp configuration on a linear motion stage driven by a stepper motor with a resolution of 8-mum/step. RESULTS The devices were significantly different statistically from each other in terms of insertion force, number of attempts and time to pass the impacted stone, radial dilation, radial extraction, and axial extraction force in the Teflon block model. No proximal migration of the stones occurred with any of the devices. The devices were similar in terms of preventing proximal stone migration, force applied to retrieve stones, and tip stiffness. CONCLUSIONS The differences in the physical characteristics of stone migration devices might help to predict their safety and efficacy in clinical use.

Celecoxib in the Management of Acute Renal Colic: A Randomized Controlled Clinical Trial

OBJECTIVES To evaluate the efficacy of celecoxib as an analgesic and medical expulsive agent in acute renal colic. METHODS A prospective randomized double-blind study was conducted on patients presenting with an obstructing ureteral calculus < 10 mm in largest diameter. Patients were randomized to 400 mg of celecoxib, followed by 200 mg every 12 hours for 10 days, or to placebo. Patients with a solitary kidney, renal insufficiency (CR > 1.8), urinary tract infection, or significant cardiovascular disease were excluded. RESULTS A total of 57 patients provided consent of which 53 completed the study. Four patients were excluded from the analysis because of stone passage or withdrawal of consent before the first dose of study medication. No significant difference was noted in the spontaneous stone passage rate (celecoxib 55.2%, placebo 54.2%) and between celecoxib and placebo with regard to days to stone passage (7.0 vs 9.0, P = .6) or size of stone passed (3.9 vs 4.6 mm, P = .18). No significant difference was noted in pain analog scores (2.6 vs 3.5, P = .71) or narcotic doses (13.2 vs 13.6, P = .74). Furthermore, a 25% decrease in narcotic use (or 19 mg based on placebo mean) was outside the 80% one-sided confidence interval for the change in mean narcotic use between the 2 groups. Thus, it is unlikely (< 20%) that we missed a clinically significant beneficial effect of celecoxib on narcotic consumption because of sample size. CONCLUSIONS Celecoxib does not facilitate stone passage or decrease narcotic requirements in patients with acute renal colic.

Durability of reusable holmium:YAG laser fibers: a multicenter study.

PURPOSE Single use and reusable variants of holmium:YAG laser fibers are available to treat calculi during ureteroscopic procedures. In this prospective, multicenter study we evaluated a series of reusable holmium:YAG laser optical fibers. We hypothesized that reusable fibers provide a cost advantage over single use variants. MATERIALS AND METHODS We prospectively recorded fiber data, including type, size, number of uses, laser pulse energy and frequency, and total energy delivered. All fibers were new and purchased off the shelf by staff at each institution. We performed a cost analysis comparing reusable fibers to single use variants. RESULTS During 541 procedures a total of 37 holmium:YAG optical laser fibers were used, including 21 Laser Peripherals 270 (Laser Peripherals, Golden Valley, Minnesota), 7 Laser Peripherals 365, 4 Lumenis SlimLine™ 200 and 3 Lumenis SlimLine 365 fibers. After stratifying by core size 365 μm core fibers had significantly more uses than 270 μm core fibers (average 23.5 vs 11.3, p < 0.02). By fiber type the mean ± SE number of uses was 12.8 ± 2.44, 3 ± 0.4, 21.3 ± 7.12 and 28.7 ± 6.69 for the Laser Peripheral 270, Lumenis SlimLine 200, Laser Peripherals 365 and Lumenis SlimLine 365, respectively. The total cost savings for reusable fibers vs single use variants was