Sabato, 23 Ottobre, 2010

J Urol. 2010 Aug;184(2):579-83. Epub 2010 Jun 19

Adequacy of a single 24-hour urine collection for metabolic evaluation of recurrent nephrolithiasis.

Castle SM, Cooperberg MR, Sadetsky N, Eisner BH, Stoller ML.

Department of Urology, University of California-San Francisco, San Francisco, California, USA.


PURPOSE: There is much debate about whether 1 or 2, 24-hour urinalyses are adequate for metabolic evaluation of stone formers. We determined whether repeat 24-hour urine collection provides information similar to that of the initial 24-hour urine collection and whether repeat collection is necessary.

MATERIALS AND METHODS: We analyzed 2, 24-hour urine collections in 777 patients obtained from 2001 to 2005. Samples were collected 3 days or less apart before pharmacological intervention and analyzed elsewhere for routine stone risk profiles of urine calcium, oxalate, citrate, uric acid, sodium, potassium, magnesium, phosphorus, ammonium, chloride, urea nitrogen and creatinine.

RESULTS: No parameters showed a statistically significant difference between 24-hour urine samples 1 and 2 when mean values were compared (pairwise t test each p >0.05, range 0.06 to 0.87). Using Pearson’s correlation all parameters showed positive correlation coefficients (r = 0.68 to 0.89, each p <0.0001). The mean of individual patient differences in samples 1 and 2 were compared to 0 and 6 of 12 showed no difference (p >0.05) while for the remaining 6 p value was <0.05. The percent difference was 0.5% to 4.19% for all urinary parameters.

CONCLUSIONS: One 24-hour urine sample is sufficient for metabolic evaluation of recurrent stone disease. There is no significant difference in 12 urinary parameters between 24-hour urine samples collected within 3 days of each other. This information is useful to providers and may decrease patient inconvenience and the overall cost of metabolic stone evaluation.

Urology. 2010 Jun;75(6):1289-93

Relationship between body mass index and quantitative 24-hour urine chemistries in patients with nephrolithiasis.

Eisner BH, Eisenberg ML, Stoller ML.

Department of Urology, Massachusetts General Hospital, Boston, MA 02114, USA.


OBJECTIVES: To examine the relationship between body mass index and 24-hour urine constituents in a population of stone-forming patients.

METHODS: A total of 880 patients who presented to a metabolic stone clinic for initial evaluation were analyzed. Patients were stratified by gender and divided into quartiles of body mass index. Associations between body mass index (BMI) and urine parameters were explored using bivariate and multivariate linear regression.

RESULTS: On bivariate analysis, increasing body mass index was associated with a significant increase in sodium, calcium, citrate, uric acid, magnesium, calcium oxalate, uric acid, and a decrease in pH in men. In women, it was associated with a significant increase in sodium, uric acid, oxalate, uric acid, and decreasing pH. On multivariate analysis, BMI was associated only with increases in sodium and calcium oxalate and decrease in pH in men. In women, multivariate analysis demonstrated positive association between BMI and urine sodium, creatinine, and phosphate and a negative relationship with urine citrate and sulfate.

CONCLUSIONS: Increasing body mass index was related to several risk factors for urinary stone disease in this study, including increasing urine sodium and decreasing pH in men and increasing urine uric acid, sodium, and decreasing urine citrate in women. Just as general recommendations for patients with nephrolithiasis include high voided volumes, low dietary sodium, and low animal protein intake, perhaps weight reduction should be included as part of the counseling of stone-formers to optimize 24-hour urine parameters.

Urol Int. 2010;84(3):260-4. Epub 2010 Apr 13

Treatment of ureteral calculi with semirigid ureteroscopy: where should we stop?

Yencilek F, Sarica K, Erturhan S, Yagci F, Erbagci A.

Department of Urology, Yeditepe University Medical Faculty, Istanbul, Turkey.


OBJECTIVES: To evaluate the efficacy of semirigid ureteroscopy in the management of ureteral stones located in different parts of the ureter.

METHODS: 1,503 patients were treated with semirigid ureteroscopy. All ureteral stones were either removed only by a basket catheter or disintegrated by pneumatic lithotripsy. Success rates, auxiliary procedures, complication rates and operation time were comparatively evaluated according to stone location.

RESULTS: Overall, mean stone size and age were 12.1 +/- 3.7 mm and 43.2 +/- 9.72 years, respectively. While 1,416 patients (94.2%) were completely stone-free, the procedure was unsuccessful in 87 cases (5.8%). The success rate was relatively low in the proximal ureter (71.7%) when compared with the mid (94.8%) and distal ureter (98.9%) (p = 0.021). Mean operation time was 25.4 +/- 11.7 min. Longer duration of operation and higher complication rate were found in proximal ureteral calculi. Stone migration to the kidney and hematuria were the main reasons of failure in the proximal ureter and ureteral stenting was needed for 56.4% of patients with upper ureteral stone.

CONCLUSIONS: Semirigid ureteroscopy can be the treatment of choice in lower and midureteral stones. However, it is an invasive and less successful treatment modality for proximal ureteral stones with relatively high complication rates.

J Endourol. 2010 Jun;24(6):955-60.

Comparison of outcomes after percutaneous nephrolithotomy of staghorn calculi in those with single and multiple accesses.

Akman T, Sari E, Binbay M, Yuruk E, Tepeler A, Kaba M, Muslumanoglu AY, Tefekli A.

Department of Urology, Haseki Teaching and Research Hospital, Istanbul, Turkey.


PURPOSE: To analyze the early outcome after single tract vs multiple tracts percutaneous nephrolithotomy (PCNL) in the management of staghorn calculi.

PATIENTS AND METHODS: The records of 413 patients with staghorn calculi (223 [54%] had complete and 190 [46%] had partial) who underwent PCNL were reviewed retrospectively. A total of 244 (59%) patients were managed by single access (group 1); meanwhile, multiple accesses were necessary in 169 (41%) patients (group 2). Both groups were compared in terms of perioperative findings and postoperative outcomes. Patients and stone-related factors affecting the number of accesses performed were analyzed.

RESULTS: The mean number of percutaneous accesses was 2.42 +/- 0.74 (range 2-6) in group 2. Mean durations of fluoroscopy screening time and operative time were significantly longer in group 2 (P = 0.002, P < 0.0001, respectively). Supracostal access was necessary in 30.7% in group 2 and in 6.9% in group 1 (P = 0.001). Success was achieved in 70.1% in group 1 and in 81.1% for group 2 after one session of PCNL (P = 0.012). The most common complication was bleeding for both groups, and it was higher in group 2 (P < 0.0001). The mean preoperative and postoperative creatinine concentrations were 1.03 mg/dL and 1.08 mg/dL in group 1, and 0.9 mg/dL and 1.03 mg/dL in group 2, respectively. The mean changes in creatinine values were not statistically significant between the groups (P = 0.16).

CONCLUSIONS: The impact of PCNL using either single or multiple access tracts on renal function is similar and of a temporary nature. PCNL with multiple accesses is a highly successful alternative with considerable complication rates in the management of staghorn calculi.

J Urol. 2010 Feb;183(2):585-9. Epub 2009 Dec 16.

Medical expulsive therapy for ureteral calculi in the real world: targeted education increases use and improves patient outcome.

Brede C, Hollingsworth JM, Faerber GJ, Taylor JS, Wolf JS Jr.

Department of Urology, University of Michigan, Ann Arbor, Michigan 48109-0330, USA.


PURPOSE: In controlled trials medical expulsive therapy has improved outcomes in patients with ureteral stones but its real-world use and effectiveness outside a clinical trial have not been thoroughly examined. We studied the impact of targeted education of emergency department physicians about medical expulsive therapy and analyzed its impact on patient outcomes and cost.

MATERIALS AND METHODS: In 2006 emergency department physicians at our institution were formally educated about medical expulsive therapy. Retrospective emergency department data were collected on patients with ureteral stones from 2003 and 2005 (before educational intervention), and 2007 (after intervention). Cost and 90-day post-emergency department event data were gathered from a health maintenance organization owned and operated by our medical center. Medical expulsive therapy prescribing trends, adverse outcome (repeat emergency department visit, hospital admission or surgery) and total cost related to ureteral calculus diagnosis were analyzed.

RESULTS: Of 166 health maintenance organization patients with ureteral calculi who met all study requirements 97 (58.4%) were prescribed medical expulsive therapy and 53 (31.9%) filled the medical expulsive therapy prescription, while 113 did not. Analysis revealed a 2-fold increase in medical expulsive therapy prescribing and a 4-fold increase in prescribing alpha-blockers in each time increment. Bivariate analysis showed that the frequency of adverse outcomes was lower in the medical expulsive therapy group (37.7% vs 53.1%) and medical expulsive therapy was associated with a lower mean total cost per patient ($1,805 vs $2,372).

CONCLUSIONS: Targeted educational intervention can increase the use of preferred medical expulsive therapy (alpha-blockers) in the emergency department. Medical expulsive therapy decreases the incidence of adverse events by 29% and decreases the total cost associated with ureteral stones by 24%.

J Urol. 2010 Feb;183(2):576-9. Epub 2009 Dec 16.

Hypertension is associated with increased urinary calcium excretion in patients with nephrolithiasis.

Eisner BH, Porten SP, Bechis SK, Stoller ML.

Department of Urology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts 02114, USA.


PURPOSE: The epidemiological relationship between nephrolithiasis and hypertension is well-known. Patients with hypertension are at increased risk for nephrolithiasis and those with nephrolithiasis are at risk for hypertension. Urine calcium or urine citrate may be related to hypertension status. We examined the relationship between hypertension and 24-hour urine composition in patients with nephrolithiasis.

MATERIALS AND METHODS: We retrospectively reviewed the database on 462 stone forming patients to examine the relationship between hypertension and 24-hour urine composition. Multivariate linear regression models were adjusted for age, race, gender, body mass index, diabetes mellitus and 24-hour urine constituents. Nominal logistic regression was also done to examine the hypertension prevalence by quintile of calcium and citrate excretion.

RESULTS: On adjusted multivariate analysis compared with normotensive stone formers those with hypertension excreted 25.6 mg per day more urine calcium, corresponding to a 12% increase in urinary calcium excretion. The relative risk of hypertension was significantly associated with quintile of calcium excretion but not with quintile of citrate excretion (1.29, 95% CI 1.02 to 1.61 vs 0.94, 95% CI 0.78 to 1.14).

CONCLUSIONS: In stone formers hypertension was associated only with significantly increased urine calcium. This association is important when treating patients with nephrolithiasis since those with hypertension may require unique dietary and medical therapy.

J Urol. 2010 Jun;183(6):2244-8. Epub 2010 Apr 18

Diabetic kidney stone formers excrete more oxalate and have lower urine pH than nondiabetic stone formers.

Eisner BH, Porten SP, Bechis SK, Stoller ML.

University of California-San Francisco, San Francisco, California, USA.


PURPOSE: The epidemiological relationship between nephrolithiasis and type 2 diabetes mellitus is well-known. Patients with diabetes mellitus are at increased risk for nephrolithiasis and those with nephrolithiasis are at risk for diabetes mellitus. We examined 24-hour urine composition in stone formers with and without diabetes mellitus.

MATERIALS AND METHODS: We retrospectively reviewed a database of 462 stone forming patients to examine the relationship between hypertension and 24-hour urine composition. Multivariate linear regression models were adjusted for age, race, gender, body mass index, hypertension, relevant medications and 24-hour urine constituents.

RESULTS: On univariate analysis diabetic patients had significantly greater urine volume than nondiabetic patients (2.5 vs 2.1 l daily, p = 0.004). Those with diabetes mellitus also excreted less daily potassium (61.1 vs 68.8 mEq, p = 0.04), phosphate (0.84 vs 1.0 gm, p = 0.002) and creatinine (1405.5 vs 1562.8 mg, p = 0.03), and had significantly lower daily urine pH (5.78 vs 6.09, p <0.001) and CaP supersaturation (0.49 vs 1.20, p <0.001) than nondiabetic patients. On multivariate analysis compared to patients without diabetes mellitus those with type II diabetes mellitus had significantly lower urine pH (-0.34, 95% CI -0.48 to -0.21) and significantly greater urine oxalate (6.43 mg daily, 95% CI 1.26 to 11.60) and volume (0.38 l daily, 95% CI 0.13 to 0.64).

CONCLUSIONS: Results show that of stone formers patients with type II diabetes mellitus excrete significantly greater urinary oxalate and significantly lower urine pH than those without diabetes mellitus. These findings are important for treating nephrolithiasis since they may influence dietary counseling, medical management and stone prevention.

Urol Int. 2010;84(3):254-9. Epub 2010 Apr 13

Treatment of ureteral lithiasis with tamsulosin: literature review and meta-analysis.

Arrabal-Martin M, Valle-Diaz de la Guardia F, Arrabal-Polo MA, Palao-Yago F, Mijan-Ortiz JL, Zuluaga-Gomez A.

Department of Urology, San Cecilio University Hospital, Granada, Spain.

OBJECTIVE: Ninety percent of ureteral calculi <4 mm are expelled over a period of 3 months; if they are >6 mm the elimination possibilities are reduced to 30%. Presently, investigations in the treatment of ureteral lithiasis have the objective of modifying ureter contractibility with the aid of calcium antagonist and alpha-blocking drugs. The objective of this study is to analyze the effect of tamsulosin in the treatment of the distal ureter lithiasis and to make a systematic analysis of the literature.

PATIENTS AND METHODS: In a prospective study 70 cases of distal ureter lithiasis were divided into 2 groups: group 1 = 35 cases treated with ibuprofen (600 mg/12 h) and 2,000 ml water/24 h with tramadol on demand, and group 2 = 35 cases with the same treatment as described before plus tamsulosin 0.4 mg/day over 3 weeks. The number of stone-free patients, time to expulsion and the necessity for analgesia were evaluated. A literature review (2002-2007) and meta-analysis of 11 studies was performed. Statistical analysis included relative risk (RR), number needed to treat (NNT) and chi(2) test.

RESULTS: Group 1 reported 19 stone expulsions (54.3%) and group 2 30 expulsions [85.7%, chi(2) = 8.23 (p < 0.01), RR = 1.58, NNT = 3 (95% CI 2-9)]. The mean time to expulsion was 14 days in group 1 and 8 days in group 2. No side effects were detected. Meta-analysis included 792 patients: 392 patients in group 1 and 400 patients in group 2. Group 1 reported 211 stone expulsions (53.8%) and group 2 reported 332 expulsions [83%, chi(2) = 78.17 (p < 0.01), RR = 1.54, absolute benefit = 29.2% (95% CI 23-35.3%), NNT = 3 (95% CI 3-4)]. The mean time to expulsion was 9.45 days in group 1 and 6.07 days in group 2 treated with tamsulosin; a significant difference was observed in all studies.

CONCLUSIONS: Tamsulosin increases the elimination of distal ureter lithiasis of <10 mm.

J Urol. 2010 Oct;184(4):1261-6. Epub 2010 Aug 17

Tubeless percutaneous nephrolithotomy–the new standard of care?

Zilberman DE, Lipkin ME, de la Rosette JJ, Ferrandino MN, Mamoulakis C, Laguna MP, Preminger GM.

Comprehensive Kidney Stone Center, Division of Urology, Duke University Medical Center, Durham, North Carolina 27710, USA.


PURPOSE: Traditionally the placement of a nephrostomy tube at the conclusion of percutaneous nephrolithotomy is considered the standard of care. However, the need for nephrostomy tube placement has been questioned by numerous authors. We evaluated the literature regarding tubeless percutaneous nephrolithotomy, and determined potential candidates for tubeless percutaneous nephrolithotomy and whether this procedure can be considered the new standard of care for complex stone removal.

MATERIALS AND METHODS: A MEDLINE search was conducted between May 1997 and January 2010 to detect studies reporting tubeless percutaneous nephrolithotomy. “Nephrolithiasis,” “percutaneous nephrolithotomy,” “tubeless” and “lithotripsy” were used as medical subject headings (MeSH) key words. Additional citations were identified by reviewing the reference lists of the included articles. All relevant articles were reviewed for indications, outcomes and complications.

RESULTS: The data obtained from 50 reports document comparable complication rates between tubeless and standard percutaneous nephrolithotomy. Tubeless percutaneous nephrolithotomy demonstrated advantages such as less pain, less debilitation, less costs and a shorter hospital stay. Mean stone-free rates for tubeless percutaneous nephrolithotomy were as high as 89%.

CONCLUSIONS: Tubeless percutaneous nephrolithotomy appears to be safe and efficacious in uneventful procedures, in children, in obese patients, in simultaneous bilateral procedures, in supracostal access and in renal units with coexisting anatomical anomalies. Nephrostomy tube placement should still be considered in certain cases such as those with more than 2 nephrostomy access tracts, those necessitating a second look and those with intraoperative complications such as significant bleeding or collecting system perforation.

J Endourol. 2010 Jun;24(6):923-30

The role for active monitoring in urinary stones: a systematic review

Skolarikos A, Laguna MP, Alivizatos G, Kural AR, de la Rosette JJ.

Second Department of Urology, Athens Medical School, Athens, Greece.


BACKGROUND AND PURPOSE: All urinary stones may not need prompt active treatment. The aim of our study was to identify urinary stones that can be actively monitored safely.

MATERIALS AND METHODS: We performed a systematic review of the natural history and the role of active monitoring for urinary stones.

RESULTS: Thirty-seven studies have selected. Of symptomatic ureteral calculi <4 mm, 38% to 71% will pass spontaneously while only 4.8% of stones <2 mm will need intervention during surveillance. Follow-up with history, physical examination, urinalysis, and plain radiography every 2 weeks for 1 month is necessary. If spontaneous passage does not occur within this period, intervention is recommended. When shockwave lithotripsy for caliceal stones is prospectively compared with observation, there is no difference in stone-free rates (28% vs 17%), need for additional treatment (15% vs 21%), or visits to a general practitioner (18.5% vs 20.8%). Patients under observation may need more invasive procedures and may be more commonly left with residual stone fragments >5 mm (58% vs 30%). Isolated, nonuric acid calculi <4 mm may be most amenable to active monitoring. Physical examination, urinalysis, and CT scan performed on an annual basis up to year 2 or 3, followed by intervention, are recommended. Lower pole stones <10 mm could be actively monitored on an annual basis by alternating ultrasonoraphy with CT scan, provided the patients are adequately informed. Up to 58.6% and 43% of patients with residual fragments after shockwave and percutaneous lithotripsy, respectively, may become symptomatic or require intervention during follow-up. Noninfected, asymptomatic fragments, <4 mm postextracorporeal lithotripsy, and <2 mm postpercutaneous surgery could be followed expectantly on an annual basis, in combination with medical therapy.

CONCLUSION: Active stone monitoring has a certain role in the treatment of patients with urinary stones. The success is largely dependent on the stone size, location, and composition, as well as the time after the diagnosis. Medical therapy is a useful adjunct to observation.