This Month in Pediatric Urology

Article Outline

• Urinary Neutrophil-Gelatinase Associated Lipocalin is a Marker for Renal Scarring
• Percutaneous Cystolithotomy for Calculi in Reconstructed Bladders
• Compliance With Antibiotic Prophylaxis and Vesicoureteral Reflux
• Fowler-Stephens Orchiopexy
• Copyright

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Urinary Neutrophil-Gelatinase Associated Lipocalin is a Marker for Renal Scarring 

Management of vesicoureteral reflux (VUR) in children includes the detection and prevention of renal scarring, which in severe cases can lead to hypertension or renal insufficiency. Several groups have investigated urinary biomarkers as potential diagnostic tools to indicate the presence of renal scarring but none has achieved sufficient sensitivity or specificity to be used in clinical practice. Ichino et al (page 2001) from Tokyo, Japan describe their investigation of neutrophil-gelatinase associated lipocalin (NGAL), an iron carrier protein expressed in neutrophils and monocytes/macrophages, which has been shown to be a sensitive marker of renal dysfunction with up-regulation of the NGAL gene in the kidney after ischemia and increased expression in proximal renal tubules during the regenerative process after kidney injury. They evaluated urinary NGAL concentration in 34 children with VUR at least 3 months after the last infection, including 24 who were evaluated with dimercapto-succinic acid scans the same day that urine specimens were collected, and compared these levels to those of 28 normal healthy children. NGAL level was significantly higher in patients with VUR (p <0.01), although there was no correlation with VUR grade. The presence of renal scarring was significantly associated with high NGAL levels (p <0.005) in patients evaluated with renal scans. Using a cutoff value of 1, sensitivity was 89.5% and specificity was 100% for detection of renal scarring. In cases of unilateral renal scarring the relative differential function of the affected kidney inversely correlated with NGAL levels. The authors conclude that urinary NGAL levels are higher than normal in patients with VUR and renal scarring, and they may be a potential useful diagnostic biomarker of renal scarring.

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Percutaneous Cystolithotomy for Calculi in Reconstructed Bladders 

Bladder calculus is a recognized complication of augmentation cystoplasty with reported rates of 10% to 50%. Current strategies to treat bladder calculi in augmented bladders include open cystolithotomy, endoscopic transurethral cystolithopaxy, lithotripsy and percutaneous cystolithotomy. Breda et al (page 1989) from Los Angeles, California report their experience with percutaneous cystolithotomy in 74 consecutive cases of enteric bladder augmentation. The average interval between augmentation and percutaneous cystolithotomy was 4.8 years (± 2.05) and no patient had undergone previous surgical intervention for bladder stones. Ultrasonic lithotripsy was performed in 49 patients (66.2%) and stone basketing alone in 25 (33.8%). There were no intraoperative complications, conversions to open cystolithotomy or blood transfusions. All patients were determined to be stone-free by endoscopic examination at the end of the procedure, which was confirmed in 94.7% by a plain abdominal film 2 weeks after surgery. Postoperative complications included inability to catheterize the Mitrofanoff after suprapubic tube removal in 2 cases, urinary tract infections in 2, calcification of the suprapubic tube requiring surgical revision in 1 and fevers managed with intravenous antibiotics in 4. The authors conclude that endoscopically assisted percutaneous cystolithotomy is safe and effective treatment for calculi in augmented bladders.

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Compliance With Antibiotic Prophylaxis and Vesicoureteral Reflux 

A mainstay of medical management of VUR is continuous low dose antibiotic prophylaxis. Patient compliance with daily antibiotic prophylaxis is vital to the success of this therapy as noncompliance may result in recurrent pyelonephritis and the risk of newly acquired renal scarring. Copp et al (page 1994) from San Francisco, California estimate patient compliance with antibiotic prophylaxis for VUR by identifying factors associated with noncompliance using a private national pharmacy and medical claims database. The database includes 39 million patients with longitudinal followup data for a 5-year period. Study inclusion criteria were age less than 18 years, fluoroscopic or nuclear cystography diagnosis of VUR and at least 1 year of followup data in the database. Prophylaxis criteria were 2 or more 30-day supply prescriptions, or 4 or more 14-day supply prescriptions of penicillin or cephalosporin. Compliance was determined using a medication possession ratio of 80% or greater calculated by the number of days of prescription supply in an observation period divided by the total number of days in the observation period defined as 1 year. Antibiotic compliance was adjusted for a change in antibiotics taken during acute infection or during interim hospitalizations. The most common antibiotic prescribed was trimethoprim/sulfonamide, followed by nitrofurantoins. Overall 40% of patients achieved a medication possession ratio of 80% or greater and were classified as compliant during the 1-year observation period. Noncompliance was greater with nitrofurantoins, although no attempt was made to determine if these patients were on nitrofuantoin suspension or macrodantin capsules. Increased age was associated with decreased compliance and contact with the health care system was associated with increased compliance. The authors conclude that as providers we cannot assume that patients or their parents are compliant with prescribed treatment regimens, and that we may improve compliance through increased patient contact with the health care system and stressing the importance of the treatment regimens.

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Fowler-Stephens Orchiopexy 

Transabdominal surgery for the intra-abdominal undescended testis often involves division of the spermatic vessels to achieve adequate mobilization of the testis. Controversy exists about the relative benefit of performing this maneuver as a 2-stage vs 1-stage procedure. Elyas et al (page 2012) from Ottawa, Canada report a meta-analysis of the literature on this topic using multiple electronic databases that included an assessment of the quality of the studies as well as their heterogeneity and publication bias. Of 1,807 potentially relevant articles 99 underwent a full review for assessment of quality and data abstraction, and ultimately, 61 were included in the review. Based on the details available in the articles they reviewed, the authors conclude that 1 and 2-stage Fowler-Stephens orchiopexies have fairly high success rates but the 2-stage procedure has a higher success rate, and there was no significant difference in regard to whether an open or laparoscopic approach was used for either the 1 or 2-stage procedure. However, the authors note that the level of evidence of the studies reviewed was low, and emphasize the need for randomized controlled trials.