Caliceal Diverticula Research Articles

Efficacy of modified Guy's stone score system in predicting stone-free rate after PCNL

Objective To modify the Guy's stone score system and evaluate the validation of the modified score system in grading the complexity of percutaneous nephrolithotomy (PCNL) and predicting the stone-free rate after PCNL. Methods The modified system comprises 4 grades:grade Ⅰ,solitary stone in mid/lower pole or solitary stone in the pelvis with simple anatomy; grade Ⅱ,solitary stone in upper pole or multiple stones (located in 2 or more 2 calyces) in a patient with simple anatomy or a solitary stone in a patient with abnormal anatomy; grade Ⅲ,multiple stones in patients with abnormal anatomy or stones in a caliceal diverticulum or partial staghorn calculus; grade Ⅳ,staghorn calculus or any stone in a patient with spinal injury or spine malformation ( e.g.spina bifida,scoliosis,lordosis) ; kidney dysplasia ( e.g.duplex kidney,horseshoe kidney).It was validated on a database of 145 PCNL procedures performed by a single surgeon in a stone center.The clinical outcomes were retrospectively assessed with multivariate analysis.Results Of the 145 PCNL patients,according to Guy's stone score system and the modified score system,there were 22 G1 cases (15.2％) and 22 SFR cases (100.0％) ; 27 G2 cases (18.6％) and 25 SFR cases (92.6％); 36 G3 cases (24.8％) and SFR(31,86.1％); 60 G4 cases (41.4％) and 49 SFR cases ( 81.7％ ).Showing that the modified Guy's stone score was more accurate in predicting stone-free rate after PCNL ( P ＜ 0.05 ). Conclusions The modified Guy' s stone score system can accurately predict the stone-free rate after PCNL than the old system. Key words: Percutaneous nephrolithotomy; Kidney calculi; Surgical management; Guy's stone seore system

Percutaneous Nephrolithotomy of Caliceal Diverticular Calculi: A Single Center Experience

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. 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. 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. The percutaneous management of caliceal diverticular calculi is highly effective and can be accomplished with low morbidity.

Minimally invasive percutaneous ablation of parapelvic renal cysts and caliceal diverticula using bipolar energy

Minimally invasive percutaneous ablation of parapelvic renal cysts and caliceal diverticula using bipolar energy

Unilateral Multicystic Dysplastic Kidney With Progressive Infundibular Stenosis in the Contralateral Kidney: Experience at 1 Center and Review of Literature

We analyzed the association between unilateral multicystic dysplastic kidney and subsequent contralateral infundibular stenosis, which can result in progressive calyceal dilatation, and has been linked to global hyperfiltration injury and renal impairment. During the last 10 years 200 children presented with unilateral multicystic dysplastic kidney. Of these children 5 subsequently exhibited contralateral infundibular stenosis. We reviewed the published data on multicystic dysplastic kidney as well as infundibular stenosis to examine this association further. Three patients underwent open surgical exploration since rapid progression with associated parenchymal thinning was detected. Literature review failed to identify any discussion of infundibular stenosis in studies focusing on long-term followup of children with a unilateral multicystic dysplastic kidney. Several case reports and case series discuss this condition in association with other collecting system anomalies. However, these anomalies are hypothesized to be part of a disease spectrum resulting from aberrant formation of the collecting system. Bilateral involvement has been reported in fewer than 10 cases. Our cases represent a part of the spectrum of pyelocalyceal dysgenesis that can have bilateral involvement of varying degrees. Of particular concern was the delayed presentation in some of our patients and the progressive nature of the lesions. Although exceedingly rare, we wish to highlight the association of multicystic dysplastic kidney and progressive infundibular stenosis of the contralateral kidney and renal impairment.

Caliceal diverticulum in pediatric patients: the spectrum of imaging findings

Caliceal diverticulum (CD) is uncommon in children. As compared to adults, most children with CD are symptomatic. Common complications include stone formation and infection. Correct diagnosis of CD is important for guiding management. To identify imaging findings at diagnosis and follow-up in pediatric patients with CD. We identified all patients from 2003 to 2010 with a diagnosis of CD. We reviewed presenting symptoms, underlying diseases, complications, management, and all pertinent radiological examinations. Twenty-four patients (2.6 to 18.5 years old, 11 females) had CD. Urinary tract infection was the most common (n = 8) presentation. Diagnosis of CD was based on delayed post-contrast CT in 79% of patients with only one false-negative CT. Most patients (n = 20) had a single CD; others had either 2 CDs (n = 2) or multiple CDs (n = 2). CD diameter ranged from 1.0 to 18.3 cm and grew in five of nine patients who had follow-up studies. Seven patients developed stone in the CD. Fifteen patients (63%) underwent a surgical procedure. CD is commonly solitary, often grows with time and may mimic other diagnoses, including simple cyst, complex cyst and polycystic kidney disease. Delayed postcontrast CT is highly sensitive in diagnosing CD.

The Guy's Stone Score—Grading the Complexity of Percutaneous Nephrolithotomy Procedures

To report the development and validation of a scoring system, the Guy's stone score, to grade the complexity of percutaneous nephrolithotomy (PCNL). Currently, no standardized method is available to predict the stone-free rate after PCNL. The Guy's stone score was developed through a combination of expert opinion, published data review, and iterative testing. It comprises 4 grades: grade I, solitary stone in mid/lower pole or solitary stone in the pelvis with simple anatomy; grade II, solitary stone in upper pole or multiple stones in a patient with simple anatomy or a solitary stone in a patient with abnormal anatomy; grade III, multiple stones in a patient with abnormal anatomy or stones in a caliceal diverticulum or partial staghorn calculus; grade IV, staghorn calculus or any stone in a patient with spina bifida or spinal injury. It was assessed for reproducibility using the kappa coefficient and validated on a prospective database of 100 PCNL procedures performed in a tertiary stone center. The complications were graded using the modified Clavien score. The clinical outcomes were recorded prospectively and assessed with multivariate analysis. The Guy's stone score was the only factor that significantly and independently predicted the stone-free rate (P = .01). It was found to be reproducible, with good inter-rater agreement (P = .81). None of the other factors tested, including stone burden, operating surgeon, patient weight, age, and comorbidity, correlated with the stone-free rate. The Guy's stone score accurately predicted the stone-free rate after PCNL. It was easy to use and reproducible.

Redefining the Limits of Flexible Ureterorenoscopy

Flexible ureterorenoscopic holmium laser lithotripsy allows retrograde management of renal calculi that previously needed alternative strategies. This study assesses the influences of stone size, density, and location on treatment outcomes from a large series. Data concerning patients who presented for ureterorenoscopic laser lithotripsy between May 2005 and September 2008 were retrospectively analyzed. Single-treatment success was defined as satisfactory visual clearance of stone bulk, radiopacities less than 2 mm on noncontrast CT, and no further treatment. One hundred and eighty-five patients had 236 treatments (median=51 years; range 18-83 years). Overall success rate was 90.7%. The mean ± standard deviation (SD) stone size was 13.1 ± 8.5 mm with significant differences between the successful (11.6 ± 6.7 mm) and nonsuccessful (27.8 ± 10.0 mm) outcome groups (P<0.0001, unpaired t test). Of treatments for stone size ≤ 20 mm, 96.5% were successful. Of 36 patients with stone size >20 mm, 21 (58.3%) were stone free after one treatment and 31 (86.1%) after two treatments. Hounsfield unit data did not differ significantly between the groups (mean ± SD 858 ± 388 vs 1115 ± 643, P=0.146, unpaired t test). Stone locations were: Renal pelvis, caliceal diverticula, and upper pole, midpolar, and lower pole in 61, 9, 24, 27, and 115 cases with success rates of 85%, 100%, 83%, 93%, and 94%, respectively (P=0.899, chi-square test). Clearance rates of >90% can be achieved for stones up to 20 mm with flexible ureterorenoscopy and holmium laser lithotripsy, but with larger stones, the stone-free rates reduce significantly. Therefore, 20 mm should be regarded as the upper limit of stone size that can be cleared in a single procedure. Stone density and location do not influence outcome.

Minimally invasive surgical procedures treating symptomatic caliceal diverticular calculi

Objective To investigate the approach and safety of minimally invasive surgical procedures treating symptomatic caliceal diverticular calculi. Methods Clinical data of 21 cases with symptomatic caliceal diverticular calculi were retrospectively reviewed. Twelve females and 9 males aged 22 to 57 years old. The average diameter of caliceal diverticulum was 3.7 cm (2.5-7.0 cm) and average diameter of calculi was 2.3 cm (0.8-3.5 cm). The patients underwent flexible ureteroscopic lithotripsy, PCNL or mPCNL, laparoscopic techniques and laparoscopy-assisted transperitoneal PCNL, respectively. Four cases underwent flexible ureteroscopic lithotripsy. PCNL (2 cases) or mPCNL(5 cases)were performed in 7 cases. Nine cases underwent laparoscopic techniques. Laparoscopyassisted transperitoneal PCNL was performed in 1 case. Results The operations were performed successfully in 21 cases. No case need to transfer to open surgery during the operation and no major complications like perforation or organic injury were noted. One case with iatrogenic arteriovenous fistula of the kidney after 1 week postoperative was cured by delayed hemorrhage 2 days later, while clinical symptoms of 2 cases with residue calculi relieved. 19 cases without residue calculi were followed up for 6 to 12 month without recurrence. Conclusions After handling indication of treatment efficiently and creating advisable therapeutic decision-making, minimally invasive surgical procedures treating symptomatic caliceal diverticular calculi appears to be effective and safe. Key words: Kidney calculi; Diverticulum; Nephrostomy,percutaneous

Diagnostic Utility and Clinical Value of Postpercutaneous Nephrolithotomy Nephrostogram

After percutaneous nephrolithotomy (PCNL), the current standard of care is to obtain a nephrostogram before removal of the nephrostomy tube to rule out distal ureteral obstruction. The aim of this study was to determine whether nephrostogram findings predict prolonged urinary drainage and postoperative ureteral stent insertion. Data for all patients who had nephrostomy tubes inserted post-PCNL between January and December 2006 were retrospectively reviewed. Patients with radiolucent stones, concomitant procedures, or caliceal diverticula were excluded. All nephrostograms were reviewed to identify distal ureteral obstruction without evidence of residual fragments. The Fisher's exact test was used. Fifty patients who underwent 51 PCNLs were included in the study (one patient had bilateral PCNLs). Nephrostograms were performed on median postoperative day (POD) 2 (range POD 2-8), and tubes were removed on median POD 2 (range POD 2-10). In 14 (27%) patients who had distal ureteral obstruction without ureteral stones, the nephrostomy tube was removed on the same day of nephrostography. Eight (16%) patients experienced a prolonged urinary leak (>24 hours). While obstruction on the nephrostogram predicted prolonged urinary leak (36% vs 8%; P = 0.02), none of these obstructed patients needed postoperative ureteral stent placement. A patient with a horseshoe kidney without distal ureteral obstruction had his nephrostomy removed on POD 2. He presented on POD 7 with prolonged urinary leakage and needed readmission with ureteral stent placement and Foley catheterization. While distal obstruction seems to predict prolonged urinary leakage (more than 24 hours), it may not necessitate ureteral stent placement or prolonged nephrostomy drainage because blood clot or ureterovesical junction edema resolve spontaneously with expectant management.

Comment je repère un diverticule caliciel en urétérorénoscopie souple laser

A caliceal diverticulum (CD) can now be treated by flexible ureterorenoscopy and holmium: YAG laser. This minimally invasive approach, has the advantage of allowing a retrograde and direct access of CD in the upper and mid pole, often inaccessible or difficult by percutaneous access. However, for this treatment by retrograde way, it is essential to identify the CD neck and ensure that it is accessible. The technical artifice that we describe in this article can meet this goal.

Percutaneous Nephrolithotomy: A Single Center Experience of 610 Cases

Purpose: We performed this study to evaluate the outcomes and complications of percutaneous nephrolithotomy (PCNL) at a single institute with a large series. Materials and Methods: We reviewed the medical records of 610 patients who underwent PCNL between March 1995 and June 2008 for staghorn calculi in 139 (22.8%), partial staghorn calculi in 104 (17.0%), renal pelvis stone in 222 (36.4%), proximal ureter calculi in 60 (9.8%), and calculi within a caliceal diverticulum in 85 (13.9%) patients. Stone-free status was defined as no visible residual calcification or remnant calcification smaller than 4 mm in diameter (clinically insignificant residual fragment) on a plain KUB (X-ray examination of the kidney, ureter, and bladder) image. Characteristics of the stones, operation time, stone-free rate, and complications were evaluated. Results: Initial stone burden was 665.9±600.6 mm. Average operation time was 103.2±58.6 minutes. The mean hospital stay was 7.9 days. The stonefree rate was 84.9%, and ancillary procedures were required in 66 patients (10.8%), including 34 (5.6%) second-look PCNL and 26 (4.3%) ureteroscopic procedures. In the univariate analysis for prediction of stone-free rate, hydronephrosis, stone type, stone composition, and stone burden were significant prognostic factors. In the multivariate analysis, initial stone burden was the only independent factor affecting the stone-free rate. Complications were found in 95 patients (16.1%), 5 (0.8%) of whom needed embolization due to bleeding and 23 (3.8%) of whom showed pleural complications. Conclusions: PCNL is an effective method for the treatment of staghorn, large calyceal, and some upper ureteral stones with acceptable complication rates. (Korean J Urol 2009;50:669-674) 󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏

Xanthogranulomatous pyelonephritis infiltrating the liver

We report for the first time a patient with a caliceal diverticulum that was detected in early childhood, who in adolescence developed xanthogranulomatous pyelonephritis to the diverticulum and surrounding kidney and infiltrated to the liver. The condition was treated by nonradical organ-sparing surgery and prolonged antibiotic therapy.

Percutaneous treatment of stones in pediatrics: A retrospective multicenter study

Purpose This study was conducted to investigate the cons and pros of percutaneous stone treatment in a large population of children in a retrospective manner. Material and methods Three centers with experience in pediatric stone disease were included in this study. The data regarding the patients, stones, surgery and postoperative course were collected from each center. Results 346 renal units were operated in 311 (M:211, F:100) pediatric patients. The ages ranged from 9 months to 16 year old (mean:8.6). The mean stone area was 338.7 mm 2 (25-2075). Five had horseshoe kidneys, 2 had stones in caliceal diverticula, 9 had solitary kidney and 5 children had chronic renal failure. The procedure was carried out using different sizes of instruments within a mean surgery time of 90 min (10-270) and a mean fluoroscopy time of 12.9 min. (1.5-53). 267 (77%) renal units were rendered completely stonefree without major complications. The mean hospitalization time was 5.1 days (2-31). Blood transfusion rate was 14.7%, re-PCNL was performed in 8, adjuvant SWL was done in 6. Two had nonfunctional kidneys on follow-up. Conclusions Percutaneous nephrolithotomy is a standard treatment option for most of the large stones in pediatrics with acceptable morbidity. The technique is well established and is no longer of concern for this age group. Future studies should focus on randomized comparative trials with SWL.

First Digital Flexible Ureterorenoscope: Initial Experience

Flexible ureterorenoscopy is a minimally invasive procedure that is rapidly gaining popularity as a treatment for patients with upper urinary tract lithiasis. One of the main drawbacks is the limited visualization imposed by fiberoptic technology in an endoscope, often only 7 to 8F and the fragility of fiber-based optics in a flexible endoscope. We report our initial experience with digital flexible URS and holmium laser lithotripsy using digital image capture in three patients. Two patients had upper tract calculi (1 cm lower pole calculus and 8 mm caliceal diverticular stone, respectively), and one patient underwent diagnostic URS. After basket capture and intrarenal relocation of the lower pole stone, complete stone destruction was achieved. Similarly, the caliceal diverticular stone was destroyed after holmium laser incision of the caliceal diverticulum. Remarkable improvement in image quality was observed throughout the procedures in comparison with current fiberoptic image acquisition. Minor image interference was noted during fluoroscopic screening, which increased slightly during laser activation. The first digital flexible ureterorenoscope provided excellent image quality and zoom capability, with a substantial improvement compared with fiberoptic technology. It does not require a separate light source and is an important step for the continued evolution of flexible URS as a therapeutic modality for upper urinary tract pathology.

Teaching Atlas of Interventional Radiology: Non-Vascular Interventional Procedures

1. NECK AND THORAX Nasolacrimal duct strictures Percutaneous parathyroid ablation Thyroid biopsy Mediastinal biopsy Mediastinal abscess Pleural Biopsy Pleurodesis Bronchial stenosis 2. ABDOMEN Esophageal stricture Percutaneous gastrostomy / gastrojejunostomy Strictured enteric anastomosis Malignant colonic obstruction Intussuception Abdominal abscess 2a. Liver Ultrasound guided biopsy Abscess drainage Cyst Ablation Hydatid disease Laser ablation RF ablation Cryoablation 2b. Biliary Obstructive jaundice Malignant hilar obstruction Sclerosing Cholangitis AIDS-related cholangitis Removal of bile duct calculi Intrahepatic calculi and Caroli's disease Giant common duct calculi Transjejunal biliary intervention Acute Cholecystitis Cholecystolithiasis 2c. Pancreas Pancreatic abscess Debridement of Infected pancreas necrosis Percutaneous biopsy 3. PELVIS 3a. Abscess Drainage Transgluteal drainage Transrectal drainage Transvaginal drainage 3b. Reproductive System Female infertility: An overview Fallopian tube recanalization Transcervical lysis of intrauterine adhesions Uterine cervix dilatation 4. RETROPERITONEUM 4a. Urinary System Nephrostomy and ureteral stenting Ureteral occlusion for urinary leaks Symptomatic renal cyst Staghorn calculus Accidentally ligated ureter Caliceal diverticulum calculi Retrorenal colon 4b. Adrenal Percutaneous biopsy Pseudotumor 5. MISCELLANEOUS Conscious sedation for the Interventional Radiologist Infection and sepsis: an overview for the interventional radiologist Vertebroplasty for painful hemangioma Treatment of Osteoid Osteoma Drainage / ablation of lymphoceles

Treatment of Symptomatic Caliceal Diverticula Using a Mini-Percutaneous Technique with Greater Than 3-Year Follow-Up

Caliceal diverticula can be treated with a variety of techniques. Traditional percutaneous techniques utilize nephrostomy-tract dilation to between 26F and 32F. Identification of a small diverticulum can be difficult after such dilation. The mini-percutaneous nephrolithotomy technique has been described for the treatment of nephrolithiasis. We report on two patients with caliceal diverticula treated using a mini-perc technique with long-term follow-up. Two symptomatic patients underwent treatment of posterior caliceal diverticula using a mini-perc technique. An interventional radiologist placed an 8F nephrostomy tube for access to the diverticulum. The following day, a 12F/14F ureteral access sheath was placed over a guidewire. Through the sheath, we identified the diverticulum and its neck with a 7F semirigid ureteroscope. The diverticular neck was balloon dilated to 18F, followed by fulguration with a 3F Bugbee electrode. A Double-J ureteral stent was placed antegrade from the diverticulum to the bladder, and an 8F nephrostomy tube provided external drainage. The mean operative time was 138.5 minutes, and the mean estimated blood loss was 10 mL. Neither of the diverticula contained calculi. The mean length of stay was 2.5 days, and there were no complications. The hemoglobin and creatinine values showed no significant change. Both patients remained asymptomatic at a mean follow-up of 38 months. Treatment of a caliceal diverticulum via a mini-perc technique is safe, effective technique with durable long-term results. It offers a less-invasive alternative to standard percutaneous treatment with larger access sheaths.

Quality of Life after Percutaneous Nephrolithotomy for Caliceal Diverticulum and Secluded Lower-Pole Renal Stones

The treatment of caliceal diverticulum and deeply secluded lower-pole stones is challenging, and the indications are controversial. This study assessed the changes in the quality of life (QoL) of patients undergoing percutaneous nephrolithotomy (PCNL) for symptomatic caliceal diverticula and deep lower-pole calculi to determine whether there is a change in the "bother factor" in order to improve treatment strategies for this group of patients. Twenty-two patients undergoing PCNL were evaluated prospectively using the SF36 QoL questionnaire before and 6 weeks after PCNL. The results before and after PCNL were compared individually and by group and analyzed statistically. A P value <or=0.05 was considered significant. Most (87%) of the patients were completely stone free after the procedure. Significant QoL findings were a reduction in symptoms interfering with performance at work (40%) and improved general health (33%). Although there was an overall improvement in QoL across the entire group, this reached statistical significance for only two of the seven domains of the questionnaire. In spite of a high stone-free rate, fewer than half of patients benefited subjectively from the procedure in terms of improvement of QoL. Therefore, patients should be made aware of the limited impact of surgical treatment on QoL, and asymptomatic patients can be given the option of further watchful waiting.

Cholesteatoma of the Renal Pelvis Diagnosed by Computerized Tomography

A56-year-old white male had been seen by general practitioners and urologists for complaints of intermittent macroscopic and microscopic hematuria during the last year. Bacteriuria and desquamated epithelial cells were identified on 3 prior occasions and treated with antibiotics. Cystoscopy twice and ultrasonograms of the kidney and bladder were negative. The patient was hospitalized, and voided urine specimen revealed 5 to 10 red blood cells per high power field, as well as desquamated epithelial cells and a specific gravity of 1,020. Hemoglobin was 13.4 gm, hematocrit was 38%, and differential count and blood chemistry studies were negative. Purified protein derivative tuberculin test was positive with a2c minduration, and history revealed active pulmonary tuberculosis treated approximately 15 years ago. Preenhancement computerized tomography demonstrated a laminated onion skin-like, heterogeneously dense mass in the right renal pelvis (part A of figure, arrow). An early parenchymal phase helical computerized tomogram showed minimal enhancement of the pelvic lining consistent with the inflammatory process of pyelitis (part B of figure, arrow). The mass did not enhance. An irregular, contoured, nonenhancing cystic lesion was shown at the corticomedullary junction, most likely representing a caliceal diverticulum. The onion skin-like mass in the pelvis could have been caused by a collection of debris, a precursor to a matrix stone, myceliatoma or cholesteatoma. However, there was no extension of mycelia into the ureter and collecting system, and no confirmed mycelia in the urine. Enhancement of areas of thickened epithelium in the pelvis with a characteristic tree bark appearance favors a chronic inflammatory process but this is also seen in cases of squamous metaplasia and malacoplakia. Desquamated keratin produced by squamous metaplasia may form keratin balls in the pelvis, ie

Multicystic dysplastic kidney and caliceal diverticulum in a child a coincidence or an association?

Multicystic dysplastic kidney and caliceal diverticulum in a child a coincidence or an association?

Gross Hematuria in Children: A Ten-Year Review

Gross hematuria in children is uncommon. We reviewed our experience characterizing its clinical presentation and diagnosis. The charts of all patients who presented for the 10-year period of 1994 through 2003 were reviewed, and 342 patients were identified. Of these 342 patients, 272 were boys (80%) and 70 (20%) were girls. At presentation, 21 patients (6%) were younger than 3 years (17 were boys and 4 were girls); 199 (58%) were 3 to 12 years old (155 were boys and 44 were girls); and 122 (36%) were 13 to 20 years old (100 were boys and 22 were girls). Of the 272 male patients, 52 (19%) had benign urethrorrhagia; 48 (14%) had trauma; and 48 had a urinary tract infection (14%), and 10 of those also had urologic anomalies. Of the 342 patients, 45 (13%) had one or more congenital urologic anomalies. Of these 45 patients, 20 boys and 2 girls had vesicoureteral reflux, 10 boys had posterior urethral valves, 7 boys and 1 girl had ureteropelvic junction obstruction, 7 boys had proximal hypospadias, 2 boys and 1 girl had ureterovesical junction obstruction, 2 boys and 1 girl had ureterocele, and 1 boy had caliceal diverticulum. Also, 18 patients (5%) had stones; 3 had low-grade bladder transitional cell carcinoma; and 1 had a Wilms tumor. For 118 patients (34%; 95 boys and 23 girls), no etiology was found. Gross hematuria most often had a benign cause in children and adolescents. It was more common in boys for almost all etiologic categories and ages. The extent of the urologic evaluation should depend on the clinical setting. Voiding cystourethrography is useful in those with suspicious ultrasound findings, urinary tract infection, or voiding symptoms. Cystoscopy should be reserved for the minority in whom hematuria persists or those with ambiguous imaging study findings.