Faculty Bibliography

PURPOSE/OBJECTIVE:The incidence of nephrolithiasis in the pediatric population has been steadily increasing. The miniaturization of endoscopic instruments and improvement in imaging modalities have facilitated safe and effective endourological treatment in this patient population. We reviewed the current status of pediatric stone disease management. MATERIALS AND METHODS/METHODS:A comprehensive literature review was performed using MEDLINE/PubMed to evaluate the indications, techniques, complications and efficacy of endourological stone management in children. RESULTS:In the 1980s shock wave lithotripsy revolutionized stone management in children, becoming the procedure of choice for treating upper tract calculi less than 1.5 cm. Percutaneous nephrolithotomy has replaced open surgical techniques for the treatment of stone burdens greater than 1.5 cm with efficacy and complication rates mirroring those in the adult population. However, at an increasing number of centers ureteroscopy is now being performed in cases that previously would have been treated with shock wave lithotripsy or percutaneous nephrolithotomy. Results from recent retrospective series demonstrate that stone-free rates and complication rates with ureteroscopy are comparable to percutaneous nephrolithotomy and shock wave lithotripsy. Although concerns remain with all endoscopic techniques in children regarding damage to the urinary tract and renal development, neither short-term nor long-term adverse effects have been consistently reported. CONCLUSIONS:Shock wave lithotripsy, percutaneous nephrolithotomy and ureteroscopy are highly effective endourological techniques to treat stone disease in the pediatric population. A lack of prospective randomized trials comparing treatment modalities coupled with a vast disparity in the access to resources worldwide continues to individualize rather than standardize stone treatment in children.

PURPOSE/OBJECTIVE:We studied the possibility that age, height, weight and body mass index could be used to predict the likelihood of successful ureteroscopic access to the upper urinary tract without previous stent placement in prepubertal children. MATERIALS AND METHODS/METHODS:We retrospectively reviewed all ureteroscopic procedures for upper tract calculi in prepubertal children from 2003 to 2007. We compared age, height, weight and body mass index in patients who underwent successful primary flexible ureteroscopic access and in those who required initial stent placement to perform ureteroscopy. RESULTS:Successful primary ureteroscopic access to the upper tract was achieved in 18 of 30 patients (60%). There was no difference in mean age (9.9 vs 9.5 years, p = 0.8), height (132 vs 128 cm, p = 0.6), weight (37 vs 36 kg, p = 0.86) or body mass index (19.3 vs 20.5 kg/m(2), p = 0.55) between patients with successful vs unsuccessful upper tract access. Locations that prevented access to the upper urinary tract were evenly distributed among the ureteral orifice, iliac vessels and ureteropelvic junction. CONCLUSIONS:Age, height, weight and body mass index could not predict the likelihood of successful ureteroscopic access to the upper tract. Placement of a ureteral stent for passive ureteral dilation is not necessary for successful ureteroscopic access to the renal pelvis in prepubertal children. An initial attempt at ureteroscopy, with placement of a ureteral stent if upper tract access is unsuccessful, decreases the number of procedures while maintaining a low complication rate.

PURPOSE/OBJECTIVE:In this study we identified prognostic factors for survival and validated the accuracy of the Fournier's gangrene severity index in patients with Fournier's gangrene. MATERIALS AND METHODS/METHODS:We retrospectively reviewed medical records of patients diagnosed with Fournier's gangrene between 1996 and 2006. Fournier's gangrene severity index scores were assessed using a receiver operating characteristic curve. Using an outcome variable of inpatient mortality, univariate analyses were performed using the Mann-Whitney U, chi-square and Fisher exact tests. RESULTS:A total of 68 patients (79.4% male, mean age 55.8 +/- 15.2 years) diagnosed with Fournier's gangrene met the criteria for review. The inpatient mortality rate was 10% (7 patients). The mean Fournier's gangrene severity index score for survivors was 5.4 +/- 3.5 vs 10.9 +/- 4.7 for nonsurvivors (p = 0.006). Isolated Fournier's gangrene severity index and individual laboratory parameters associated with mortality included heart rate (p = 0.05), respiratory rate (p = 0.02), serum creatinine (p = 0.03), serum bicarbonate (p = 0.001), serum lactate (p = 0.001) and serum calcium (p = 0.03). Although mean total body surface area was only suggestive of an association (p = 0.169), abdominal wall (p = 0.004) or lower extremity (p = 0.005) involvement was associated with increased mortality. Using a Fournier's gangrene severity index score threshold of 9 (sensitivity 71.4%, specificity 90%) there was a 96% survival rate in patients with a Fournier's gangrene severity index of less than 9 and a 46% mortality rate in those with a Fournier's gangrene severity index of 9 or greater (p = 0.001, OR 22, 95% CI 3.5-139.7). CONCLUSIONS:The Fournier's gangrene severity index remains an objective and simple method to quantify the extent of metabolic aberration at presentation in patients with Fournier's gangrene. A Fournier's gangrene severity index threshold value of 9 is sensitive and specific for predicting mortality in this patient population.

PURPOSE/OBJECTIVE:To describe the drainage and differential function of the horseshoe kidney. PATIENTS AND METHODS/METHODS:A retrospective review of mercaptoacetyltriglycine (MAG3) nuclear renograms from 1991 to 2007 was performed. Nineteen patients with horseshoe kidney who had not undergone previous renal surgery were identified. All studies were reviewed, and patient information was gathered. Drainage characteristics and differential function were determined. RESULTS:Nineteen primary MAG3 studies were found, representing 38 evaluable renal units. For these units altogether, the median t1/2 was 11 minutes. A t1/2 of 10 minutes or less was found in 18 units (47%), while 12 units (32%) showed a t1/2 longer than 20 minutes. The relative function difference mean was 24.6%. The number of patients with a relative function difference greater than 10% was 11 (57%), and those with a relative function difference greater than 20% was 7 (37%). CONCLUSION/CONCLUSIONS:Horseshoe kidney is associated with fairly high rates of poor renal drainage and elevated differential function.