Harry P. Koo

URETEROSCOPY FOR THE TREATMENT OF UROLITHIASIS IN CHILDREN

PURPOSE Ureteroscopy for treating urolithiasis in prepubertal children has become more common with the advent of smaller instruments. We reviewed our experience with ureteroscopy for urolithiasis in this cohort of patients as well as the literature using this treatment modality in children. MATERIALS AND METHODS Between 1994 and 2000 we performed 27 ureteroscopic stone extractions in 25 children. Ureteroscopy was done in a manner similar to that in adults. Ureteral dilation was performed when necessary to access the ureter. A stent was placed postoperatively if there was significant ureteral trauma. RESULTS Of the 25 children 13 were male and 12 were female. Average age was 9.2 years (range 3 to 14). Stones were 2 to 12 mm. in greatest diameter (average 6). Of the 27 procedures the ureteral orifice was dilated before stone treatment in 15 (56%), while in 19 (70%) a stent was placed afterward. No intraoperative and 2 postoperative complications were identified. Overall 92% of the children were rendered stone-free after 1 procedure and 100% were stone-free after 2. CONCLUSIONS Ureteroscopy for urolithiasis in prepubertal children is safe and effective. Routine ureteral dilation and ureteral stent placement are not always necessary in these patients.

RENAL TRANSPLANTATION IN CHILDREN WITH SEVERE LOWER URINARY TRACT DYSFUNCTION

PURPOSE Renal transplantation in children with end stage renal disease due to congenital urological malformations has traditionally been associated with a poor outcome compared to transplantation in those with a normal urinary tract. In addition, the optimal urological treatment for such children remains unclear. To address these issues, we retrospectively reviewed our experience with renal transplantation in this population. MATERIALS AND METHODS Between 1986 and 1998, 12 boys and 6 girls a mean age of 8.4 years with a severe dysfunctional lower urinary tract underwent a total of 15 living related and 6 cadaveric renal transplantations. Urological anomalies included posterior urethral valves in 8 cases, urogenital sinus anomalies in 4, the prune-belly syndrome in 2, and complete bladder duplication, ureterocele, lipomeningocele and the VATER syndrome in 1 each. In 11 children (61%) bladder augmentation or continent urinary diversion was performed, 2 (11%) have an intestinal conduit and 5 (28%) have a transplant into the native bladder. RESULTS In this group patient and overall allograft survival was 100 and 81%, respectively. These values were the same in all children who underwent renal transplantation at our center during this era. In the 17 children with a functioning transplant mean serum creatinine was 1.4 mg./dl. Technical complications occurred in 4 patients (22%), including transplant ureteral obstruction in 2 as well as intestinal conduit stomal stenosis and Mitrofanoff stomal incontinence. CONCLUSIONS Renal transplantation may be successfully performed in children with end stage renal disease due to severe lower urinary tract dysfunction. Bladder reconstruction, which may be required in the majority of these cases, appears to be safe when performed before or after the transplant. A multidisciplinary team approach to surgery is advantageous.

NEPHROLITHIASIS ASSOCIATED WITH THE KETOGENIC DIET

PURPOSE The ketogenic diet has been used for treating seizure disorders for more than 70 years. Nephrolithiasis is a known complication of this diet with a reported stone rate as high as 10% but there is sparse literature detailing the nature and treatment of these stones. We report on 4 children with nephrolithiasis on this diet. MATERIALS AND METHODS We describe stone treatment and analysis as well as metabolic and urine abnormalities in 4 children with nephrolithiasis on the ketogenic diet who presented to our institution. RESULTS All patients were treated with shock wave lithotripsy, fluid liberalization and oral citrate. One child was ultimately withdrawn from the diet due to persistent stone formation. Analysis revealed 3 calcium and 1 ammonium urate stones. Three patients had hypercalciuria, 2 elevated urinary uric acid and 1 hypocitruria. Serum studies revealed acidosis in 3 cases. CONCLUSIONS The ketogenic diet induces several metabolic abnormalities that increase the propensity for stone formation. Urologists should be aware of this potential complication. Fluid liberalization and bicitrate are recommended as prophylaxis.

DELAYED PRESENTATION OF POSTERIOR URETHRAL VALVES: A NOT SO BENIGN CONDITION

PURPOSE Posterior urethral valves are usually detected during infancy by prenatal sonography. Rarely they may be diagnosed during later childhood, adolescence or even adulthood. Less is known about presentation and outcome in these older patients. We reviewed our experience at 4 institutions with the late presentation of posterior urethral valves. MATERIALS AND METHODS A 13-year retrospective review revealed the late presentation of posterior urethral valves in 47 patients 5 to 35 years old (mean age 8). Data collected included presenting symptomatology, radiographic findings and renal function. Statistical analysis determined the relationships among presenting symptoms, patient age at diagnosis and renal function. RESULTS The most common presenting symptoms were diurnal enuresis in 60% of the cases, urinary tract infection in 40% and voiding pain in 13%. Other presenting symptoms in less than 10% of the cases included poor stream, gross hematuria and proteinuria. At diagnosis hydronephrosis and vesicoureteral reflux were present in 40 and 33% of the patients, respectively, while serum creatinine was elevated in 35% and end stage renal disease had developed in 10%. The severity of presenting signs and symptoms was significantly associated with renal impairment, while patient age at diagnosis was not. CONCLUSIONS Posterior urethral valves is not merely a disease of infancy. Voiding cystourethrography should be considered in boys older than 5 years who have voiding complaints, especially in association with diurnal enuresis or urinary tract infection. Patients who present late with posterior urethral valves are at risk for progression to end stage renal disease.

EXTERNAL URETHRAL SPHINCTER DILATION FOR THE MANAGEMENT OF HIGH RISK MYELOMENINGOCELE: 15-YEAR EXPERIENCE

PURPOSE We investigate the long-term outcome using external urethral sphincter dilation for high risk myelomeningocele. MATERIALS AND METHODS Since 1984 external urethral sphincter dilation was performed in 25 patients with myelomeningocele who demonstrated passive leak point pressure greater than 40 cm. H2O and/or poor bladder compliance. Mean followup from the first dilation was 8.4 years. Overall 2.4 dilations were performed per patient (range 1 to 8). Cystometrography, imaging study and continence status were evaluated retrospectively. RESULTS Overall external urethral sphincter dilation produced durable improvements in mean leak point pressure (60.9 versus 34.4 cm. H2O), capacity (119.8 versus 233.3 ml.), initial compliance (11.5 versus 28.4 ml./cm. H2O) and terminal compliance (1.1 versus 7.7 ml./cm. H2O). Categorical analysis revealed 3 groups in terms of outcome. Group 1 consisted of 11 patients (44%) who demonstrated durable improvements in urodynamic parameters as well as preservation of the upper tracts. These patients demonstrated a 2-step compliance pattern on pre-dilation cystometrography, in which elevated leak point pressure was associated with excellent initial compliance. Group 2 consisted of 5 patients (20%) who failed to maintain safe leak point pressure and whose upper tracts deteriorated, including 4 who eventually underwent augmentation cystoplasty. This group demonstrated a 1-step hypertonicity in which elevated leak point pressure was associated with a steep pressure increase during early filling. Group 3 consisted of 9 patients (36%) who responded minimally in terms of leak point pressure reduction but whose upper tracts remained well preserved. They demonstrated a high pressure instability pattern associated with excellent baseline compliance. CONCLUSIONS External urethral sphincter dilation provides an effective long-term solution for select high risk myelomeningocele cases. Those who demonstrate elevated leak point pressure and poor bladder compliance at the time of external urethral sphincter dilation are less likely to respond, suggesting that the bladder may have already undergone irreversible changes due to high outlet resistance. Patients who demonstrate instability patterns are less likely to respond to external urethral sphincter dilation in terms of leak point pressure reduction but the upper tracts appear to be well preserved.

Lower ureteral reconstruction

Lower ureteral reconstruction is commonly performed in instances of congenital anomalies and ureteral injury. Keys to a successful outcome are an understanding of ureteral anatomy, familiarity with the principles of tissue handling, and the knowledge of various techniques of repair. This article presents some important and useful reconstructive techniques that can be considered in the management of patients with congenital anomaly or lower ureteral injury.

Comments on Pediatric Elimination Dysfunctions: The Whorf Hypothesis, the Elimination Interview, the Guarding Reflex and Nocturnal Enuresis

Aims of study: This paper addresses pediatric elimination disorders including nocturnal enuresis from the perspectives of terminology (the Whorf hypothesis), the elimination interview, and the guarding reflex. Methods: The elimination interview and a modern model of normal voiding function, including the guarding reflex, are explained. Results: The language of voiding dysfunction influences our perception of it. Nocturnal enuresis, and all other voiding dysfunctions, should be evaluated by a careful elimination interview. The guarding reflex may fit into an evolving etiologic paradigm for nocturnal enuresis. Conclusions: (1) Words and phrases of eliminology should aim for simplicity, clarity and accuracy. (2) Urologists need to perfect their eliminology skills vis-à-vis the elimination interview. (3) The role of the guarding reflex in nocturnal enuresis and all other voiding dysfunctions should be critically examined.

Laparoscopy for the nonpalpable testis.

Cryptorchidism represents one of the most common childhood disorders with the incidence of testicular maldescent being 0.8% by 1 year of age. Nonpalpable testis occurs in approximately 20% of patients with cryptorchidism. Laparoscopy for diagnosis and management of nonpalpable testis has shown to be highly effective with few complications. This article reviews some of the special considerations in performing laparoscopy in children with descriptions about the unique features of a childs anatomy and physiology. The role of laparoscopy in the evaluation and management of nonpalpable testis is discussed, along with some of the controversies about how laparoscopy may be changing our approach to a child with a nonpalpable testis. Copyright