William DeFoor

Risk factors for spontaneous bladder perforation after augmentation cystoplasty

OBJECTIVES To present our experience with the use of stomach, ileum, and colon for augmentation cystoplasty to examine the incidence of, and risk factors for, spontaneous perforation. Spontaneous bladder perforation is a potentially life-threatening complication of augmentation cystoplasty with a reported incidence of up to 13%. METHODS A retrospective review of medical records from 1988 to 2001 identified 107 children (57 males and 50 females) who underwent augmentation cystoplasty at our institution. The etiology for bladder dysfunction included myelomeningocele, VATER (vertebral defects, imperforate anus, tracheoesophageal fistula, radial and renal dysplasia) syndrome, bladder and cloacal exstrophy, posterior urethral valves, and pelvic malignancy. Thirteen patients also had end-stage renal disease. RESULTS The median follow-up was 7.4 years. Gastrocystoplasty was performed in 50 children (47%), ileocystoplasty in 37 (35%), colocystoplasty in 18 (17%), and gastric-ileal composite neobladder in 2 (2%). Augmentation cystoplasty procedures were performed using a standard technique that included a two-layer anastomosis. Additional procedures at the time of reconstruction included Mitrofanoff neourethra in 66 patients (62%) and bladder neck repair in 44 (41%). Postoperatively, most patients started a strict incremental catheterization regimen. The overall incidence of bladder perforation was 5%, with one traumatic (1%) and four spontaneous (4%) perforations. All patients recovered uneventfully after exploratory laparotomy. CONCLUSIONS We believe that the relatively low incidence of spontaneous bladder perforation encountered in this series may be explained by the large number of patients with gastrocystoplasty, as well as our strict adherence to a postoperative incremental catheterization program.

Risk Factors for End Stage Renal Disease in Children With Posterior Urethral Valves

PURPOSE Obstructive uropathy secondary to posterior urethral valves is an important cause of end stage renal disease in children. Early diagnosis and intervention to decrease bladder pressure and stabilize the upper urinary tract are important to delay or prevent the progression of renal insufficiency. We analyzed the records of patients with posterior urethral valves to determine risk factors that might be predictive of ultimate renal failure. MATERIALS AND METHODS A retrospective cohort study was performed of children presenting to our institution with a diagnosis of posterior urethral valves from 1975 to 2005. Patient demographics, clinical background, laboratory and radiographic data, and renal outcomes were abstracted from the medical record. Potential risk factors were analyzed, such as high grade vesicoureteral reflux at diagnosis, nadir serum creatinine greater than 1.0 mg/dl, urinary tract infection and severe bladder dysfunction requiring clean intermittent catheterization. Risk factors were analyzed by univariate analysis with Fishers exact test. Those achieving significance were placed in a multivariate logistic regression model and an OR was generated. RESULTS A total of 142 patients were identified, of whom half presented in the neonatal period. Of the patients 119 had sufficient records for evaluation and mean followup was 7.2 years. A total of 15 patients progressed to end stage renal disease. The mean interval from diagnosis to end stage renal disease was 8.1 years. Of these patients 93% initially presented with vesicoureteral reflux and 87% ultimately required clean intermittent catheterization. Increased nadir creatinine was seen in 80% of cases. Multivariate analysis revealed that increased nadir creatinine and bladder dysfunction were independent risk factors for end stage renal disease (OR 71 and 8.9, respectively). Vesicoureteral reflux was also associated with an increased risk of end stage renal disease (OR 2.0), although this was not statistically significant. Urinary tract infections were not associated with end stage renal disease. CONCLUSIONS Patients with posterior urethral valves and severe bladder dysfunction in whom nadir creatinine remains increased are at risk for upper urinary tract deterioration, requiring renal replacement therapy. It is unclear whether high grade vesicoureteral reflux at diagnosis may also be a poor prognostic sign. Further analysis is necessary to evaluate the effects of early aggressive bladder management on renal outcomes.

Metabolic Evaluation of Children with Urolithiasis: Are Adult References for Supersaturation Appropriate?

PURPOSE We determined the incidence of urinary stone risk factors in pediatric patients with urolithiasis. MATERIALS AND METHODS Between 1998 and 2001, 71 children with urolithiasis at 2 pediatric institutions underwent metabolic evaluation. The 24-hour urine samples were analyzed outside central laboratory using adult and known pediatric references. Supersaturation and traditional metabolic parameters were determined and compared. RESULTS All patients had metabolic abnormalities. Calcium related abnormalities were present in 92% of children, calcium oxalate supersaturation was abnormal in 69%, calcium phosphate supersaturation was elevated in 70% and traditional calcium parameters were abnormal in 80%. While 11% of the patients had abnormal calcium phosphate or oxalate supersaturation with normal traditional calcium parameters, 10% had normal calcium oxalate or phosphate supersaturation with abnormal traditional calcium parameters. Low urinary volume was identified in 75% of the children. CONCLUSIONS Metabolic abnormalities are extremely common in pediatric patients with urolithiasis. Calcium related abnormalities are the most common abnormality. Urinary supersaturation values are complementary to traditional metabolic parameters and may be more sensitive predictors of recurrent stone risk. It is important to establish pediatric reference ranges to interpret these data more accurately.

Urinary Metabolic Evaluations in Normal and Stone Forming Children

PURPOSE Urinary stone disease is relatively rare in children and urinary metabolic evaluations have been the standard in our practice. We have previously reported a high rate of urinary metabolic abnormalities in stone forming children. We compared urinary chemistry values in normal and stone forming children. MATERIAL AND METHODS A prospective study was performed to assess urinary metabolic profiles in children with no history or a family history of urinary calculi. The 24-hour urine collections were performed and evaluated at an outside central laboratory. Urine chemistry studies were adjusted for creatinine. The data were compared to those on a historical cohort of calcium stone forming children. RESULTS A total of 58 samples from normal children and 142 from stone forming children were evaluated. Mean age was 10 years in normal children and 12 years in stone forming children. of the normal and stone forming children 45% and 51%, respectively, were female. Supersaturation levels of calcium oxalate as well as calcium to creatinine levels were significantly higher in children with stones. No data confounding by age or sex was identified by stratification. CONCLUSIONS There are significant differences in urinary metabolic evaluations between normal and stone forming children. This may allow more precise treatment to prevent recurrent stone episodes. We continue to perform metabolic evaluations in all children with documented urolithiasis.

Urinary Metabolic Evaluations in Solitary and Recurrent Stone Forming Children

PURPOSE We have previously reported a high rate of urinary metabolic abnormalities in stone forming children compared to normal controls. At our institution a 24-hour urine evaluation is initiated after the first stone episode in children, to measure stone risk indices. The purpose of this study was to determine which children are at the greatest risk for recurrent stone formation. MATERIALS AND METHODS A retrospective cohort study was performed to assess urinary metabolic profiles in children with urolithiasis. In all patients 24-hour urine collections were performed and evaluated elsewhere. Urine chemistry assessments such as calcium and citrate were adjusted for creatinine and weight. Calcium oxalate supersaturation was measured. Patients were stratified as solitary or recurrent stone formers based on review of the medical record. Univariate analysis between means was performed with a 2-tailed t test. RESULTS A total of 148 samples from 88 solitary stone formers and 84 samples from 51 recurrent stone formers were evaluated. Age and gender were well matched between the 2 groups. Timed urinary calcium levels referenced to creatinine and citrate were significantly higher in patients with recurrent stones. Supersaturation levels of calcium oxalate were higher in recurrent stone formers but did not reach statistical significance. CONCLUSIONS There are significant differences in 24-hour urinary calcium levels between solitary and recurrent calcium stone forming children. A patient with increased urinary calcium indices on a 24-hour specimen may benefit from more aggressive initial dietary and pharmacological treatment to prevent stone recurrence.

Risk Factors for Urinary Tract Infection After Dextranomer/Hyaluronic Acid Endoscopic Injection

PURPOSE Endoscopic injection of dextranomer/hyaluronic acid is an option for primary vesicoureteral reflux. Few groups have assessed the rate of urinary tract infection after dextranomer/hyaluronic acid injection. We reviewed our experience with dextranomer/hyaluronic acid injection, and determined the incidence of and risk factors for postoperative urinary tract infection. MATERIALS AND METHODS A retrospective cohort study was performed of all children with primary vesicoureteral reflux treated with dextranomer/hyaluronic acid from 2002 to 2007 at a single institution. Patient demographics and clinical outcomes were abstracted from the medical record. Risk factors for postoperative urinary tract infection, including female gender, preoperative vesicoureteral reflux grade, recurrent urinary tract infection, bladder dysfunction, nephropathy and persistent vesicoureteral reflux after surgery, were analyzed in a multivariate logistic regression model. RESULTS We treated 311 children, of whom 87% were female and 13% were male (464 renal units), during the study period. Mode of presentation was urinary tract infection in 85% of cases. Mean followup was 2.6 years. Postoperatively urinary tract infection developed in 40 patients (13%) and febrile urinary tract infection developed in 11 (3.5%). Of patients with urinary tract infection 26 had initially negative postoperative voiding cystourethrogram, of whom 16 underwent repeat voiding cystourethrogram and 9 showed recurrent vesicoureteral reflux. Five of these 9 patients had clinical pyelonephritis. Of assessed risk factors only preoperative recurrent urinary tract infection (OR 2.2, p = 0.03) and bladder dysfunction (OR 3.3, p = 0.001) were independent predictors of post-injection urinary tract infection. CONCLUSIONS In our series urinary tract infection after dextranomer/hyaluronic acid injection was rare. Patients with recurrent urinary tract infections and bladder dysfunction preoperatively are at increased risk for urinary tract infection after treatment. Patients with febrile urinary tract infection after dextranomer/hyaluronic acid injection are at high risk for recurrent vesicoureteral reflux.

The Risk of Recurrent Urolithiasis in Children Is Dependent on Urinary Calcium and Citrate

OBJECTIVES To determine which risk factors help predict recurrent stone formation. Urinary stone disease is relatively rare in children. At our institution, a full urinary metabolic evaluation is initiated after the first stone episode. METHODS A retrospective cohort study was performed to assess urinary metabolic profiles in children with urolithiasis. Twenty-four-hour urine collections were performed and evaluated. Urine chemistries were adjusted for creatinine and weight. Abnormal thresholds were obtained from the available published data. The patients were stratified into solitary or recurrent stone formers by review of the medical record. Multivariate analysis was performed with a logistic regression model to assess for independent risk factors for stone recurrence. RESULTS A total of 148 samples from 88 patients with solitary stones and 84 samples from 51 patients with recurrent stones were evaluated. Age and gender were well-matched between the 2 groups. Most known stones were calcium oxalate, and there were no radiolucent stones in those with unknown composition. A significantly higher number of patients with recurrent stones had abnormal values for calcium (73% vs 57%) and citrate (30% vs 13%) by univariate analysis. Both calcium (odds ratio, 2.3, P <.01) and citrate (odds ratio, 3.5, P <.001) remained independent risk factors for stone recurrence by multivariate analysis. CONCLUSIONS There are significant differences in the urinary calcium and citrate levels between children with solitary and recurrent calcium stone formation. This may allow identification of patients at risk for stone recurrence that may benefit from more aggressive dietary and/or pharmacologic intervention.

Infant robotic pyeloplasty: Comparison with an open cohort

OBJECTIVE To present our experience with infant pyeloplasty, comparing outcomes between robotic-assisted laparoscopic pyeloplasty (RALP) and open pyeloplasty (OP). MATERIALS AND METHODS A retrospective review was performed of all children <1 year of age who underwent unilateral dismembered pyeloplasty at a single pediatric institution since January 2007. Patients with standard laparoscopic pyeloplasty were excluded. Patient demographics, intraoperative details, narcotic usage, and complications were reviewed. RESULTS A total of 70 infants (51 boys and 19 girls) were identified, with nine RALP and 61 OP performed. Median age was 9.2 months (range, 3.7-11.9 months) for RALP and 4.1 months (range, 1.0-11.6 months) for OP (p = 0.005). Median weight was 8 kg (range, 5.8-10.9 kg) for RALP and 7 kg (range, 4-14 kg) for OP (p = 0.163). Median operative time was 115 min (range, 95-205 min) for RALP and 166 min (range, 79-300 min) for OP (p = 0.028). Median hospital stay was 1 day (range, 1-2 days) for RALP and 3 days (range, 1-7 days) for OP (p < 0.001). Median postoperative narcotic use of morphine equivalent was <0.01 mg/kg/day (range, 0-0.1 mg/kg/day) for RALP and 0.05 mg/kg/day (range, 0-2.2 mg/kg/day) for OP (p < 0.001). Median follow-up was 10 months (range, 7.2-17.8 months) for RALP and 43.6 months (3.4-73.8 months) for OP (p < 0.001). The success rate was 100% for RALP and 98% for OP. CONCLUSIONS Infant RALP was observed to be feasible and efficacious with shorter operative time, hospital stay, and narcotic utilization than OP.

Safety of gentamicin bladder irrigations in complex urological cases

PURPOSE Recurrent urinary tract infections are common in complex pediatric urological cases, particularly those requiring clean intermittent catheterization. At our institution gentamicin bladder irrigations have been used for antimicrobial prophylaxis and to treat symptomatic bacteriuria, particularly when the infection does not involve the upper urinary tract. The purpose of this study was to assess the safety of this therapy. MATERIALS AND METHODS A retrospective study was performed of all children treated with gentamicin bladder irrigations from 1999 to 2004. The dose was 14 mg gentamicin in 30 ml saline instilled via catheter once or twice daily. Serum creatinine and random gentamicin levels were obtained according to a protocol based on risk of gentamicin toxicity. Patient demographics, laboratory results and outcomes were abstracted from the medical records. RESULTS A total of 80 patients (38 males and 42 females) were identified. Median patient age was 10 years and median duration of treatment was 90 days. No patient had detectable serum gentamicin levels greater than 0.4 mg/dl. Small increases in serum creatinine were seen in 3 patients, all of whom had chronic renal insufficiency. A total of 21 patients (26%) had breakthrough UTIs, of which 5 (24%) were gentamicin resistant. No adverse events were documented. CONCLUSIONS Gentamicin bladder irrigations are a helpful adjunct in the management of complex pediatric urological cases involving recurrent symptomatic bacteriuria. We no longer require intensive laboratory monitoring of low risk patients at our institution.

Unusual bladder masses in children.

Benign and malignant bladder masses in children are extremely rare pathologic lesions. The presentation can include gross hematuria, irritable or obstructive voiding symptoms, and urinary infection. We present 2 cases in which large bladder masses suspicious for malignancy were diagnosed as benign lesions. One patient presented with abdominal pain and frequency 2 weeks after a minor bicycle accident and had a bladder wall abscess with sterile urine. Another child presented with gross hematuria and was found to have a giant cystitis glandularis lesion with no precipitating event or infection. The evaluation and differential diagnosis are discussed, and a review of the literature is presented.