This Month in Pediatric Urology

Article Outline

• Failed Pyeloplasty in Children
• Prenatally Diagnosed Unilateral Hydronephrosis
• Fetal Serum Beta2-Microglobulin Before and After Bladder Shunting
• Renal Volume Reduction in Refluxing and Nonrefluxing Kidneys
• Variability in Urodynamic Parameters With Position Change
• Natural History and Etiology of High Pressure Voiding in Male Infants
• Climatic Conditions and the Risk of Testicular Torsion in Adolescent Males
• 2006 Biennial Meeting of the International Children’s Continence Society
• Copyright

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Failed Pyeloplasty in Children 

There are many therapeutic options for children with a failed pyeloplasty, including open repair, laparoscopic repair and endopyelotomy. Braga et al (page 2571) from Toronto, Canada retrospectively reviewed their experience with 32 children with a recurrent ureteropelvic junction (UPJ) obstruction. Retrograde endopyelotomy was performed in 18 patients. Early in the series electrocautery incision was done followed by insertion of a 5 mm ureteral dilating balloon. Later in the series the holmium:YAG laser was used. Re-do pyeloplasty was performed in 14 children (open in 12 and laparoscopic in 2). A Double-J® stent was left postoperatively in all patients for 8 to 12 weeks. At followup endopyelotomy with electocautery was successful in 1 of 8 and endopyelotomy with the holmium:YAG laser was successful in 6 of 10 cases. The success rate was lowest for children younger than age 4 years and those with a narrow ureteral segment. Some of the patients underwent a second or third endopyelotomy and ultimately 12 of the 18 had a successful outcome after a total of 18 procedures. The success rate was 100% following open repair. These data suggest that re-do pyeloplasty has a higher success rate than endopyelotomy in children with recurrent ureteropelvic junction obstruction.

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Prenatally Diagnosed Unilateral Hydronephrosis 

There is interest in developing a serum or urinary parameter that correlates with upper urinary tract obstruction. Bajpai et al (page 2580) from New Delhi, India analyzed 90 children with suspected UPJ obstruction and studied plasma renin activity (PRA), split renal function, glomerular filtration rate and serum creatinine. Overall 57% of the patients had grade 4 hydronephrosis. A total of 50 children underwent pyeloplasty because of a decrease in differential renal function, abdominal/flank mass or abdominal pain. In these patients there was a 65% increase in mean PRA (15.6 to 26.2) between the initial measurement and immediately preoperatively. Following pyeloplasty PRA returned to normal in 88% of the cases and decreased in the remainder. Functional recovery greater than 10% occurred in 75% of patients with return of normal PRA and did not improve in those in whom PRA remained increased. In the 40 children who had not undergone surgical repair mean PRA increased from 8.1 to 13.2, which was slightly below the initial level in children who underwent surgical intervention. The authors conclude that PRA may be useful in the management of hydronephrosis and suspected upper tract obstruction.

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Fetal Serum Beta₂-Microglobulin Before and After Bladder Shunting 

Fetal bladder shunting is performed occasionally in children with severe lower urinary tract obstruction and oligohydramnios. Fetal urinary electrolytes and beta₂-microglobulin typically are measured. Craparo et al (page 2576) from Milano, Italy retrospectively analyzed the urinary and fetal serum levels of beta₂-microglobulin in 12 fetuses. Serial analysis of urinary and serum parameters before shunting was not performed. Following placement of a vesicoamniotic shunt oligohydramnios persisted in 2 fetuses with increased beta₂-microglobulin. In 10 cases amniotic fluid reaccumulated for a minimum of 4 weeks. In 4 cases the serum beta₂-microglobulin increased and all had renal failure following delivery. In 6 cases beta₂-microglobulin was unchanged or decreased after shunting, including 4 with normal renal function. The authors recommend that serum beta₂-microglobulin may be useful in the assessment of the fetus with obstructive uropathy and oligohydramnios.

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Renal Volume Reduction in Refluxing and Nonrefluxing Kidneys 

Renal parenchymal damage is a well recognized sequela of urinary tract infection and vesicoureteral reflux. Chang et al (page 2550) from Palo Alto, California retrospectively reviewed renal volumes obtained by magnetic resonance imaging in children with and without reflux, as well as a control group. Children with reflux were subdivided into those with grades IV and V, and grades I to III reflux. There was a significant reduction in renal size of refluxing and nonrefluxing kidneys compared to controls. There was a direct association between renal parenchymal loss and increasing grades of reflux. The disparity in renal volumes increased with age. At followup 43% of patients with low grade reflux and 10% with high grade reflux had spontaneous resolution. In these patients there was no statistically significant difference between these renal volumes and those of normal controls. The authors conclude that magnetic resonance imaging may be useful in the management of reflux and urinary tract infection, and note that even nonrefluxing kidneys in these children appear to be smaller than normal.

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Variability in Urodynamic Parameters With Position Change 

Whether urodynamic studies should be performed in children supine and/or upright is controversial. Lorenzo et al (page 2567) from Toronto, Canada analyzed 48 children with a mean age of 10.4 years who underwent urodynamics in the supine and sitting positions. The volume infused and infusion rate did not change for the 2 positions. No statistically significant difference was noted in maximum cystometric capacity, detrusor leak point pressure or pressure specific volumes at 20 and 30 cm water in either position. However, lower values were noted with the sitting position for volume at first sensation, volume at which detrusor overactivity was first detected and incontinence episodes. The authors recommend performing the study in the sitting position if tolerated for increased detection of detrusor overactivity and incontinence.

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Natural History and Etiology of High Pressure Voiding in Male Infants 

Voiding detrusor pressure is thought to be higher in male infants than in older children and adults. Ichino et al (page 2561) from Matsumoto, Japan retrospectively reviewed 106 videourodynamic studies from 78 males, 0 to 34 months old. Of the 78 patients 45 had had a febrile urinary tract infection, including 31 with reflux, and 33 had congenital renal abnormalities but no neurological disorders or lower urinary tract symptoms. Significant increase in detrusor pressure, increased sphincter electromyography activity, dilated posterior urethra and interruption of the urinary stream were observed. The increase in detrusor pressure in response to sphincteric contraction gradually diminished with age. The authors conclude that the high voiding pressure in male infants results from detrusor-sphincter discoordination and detrusor hypercontractility, and its improvement with maturation results from resolution of detrusor hypercontractility.

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Climatic Conditions and the Risk of Testicular Torsion in Adolescent Males 

The risk factors for acute testicular torsion are poorly understood. Srinivasan et al (page 2585) from New Hyde Park, New York retrospectively analyzed 58 boys who presented with testicular torsion and studied the mean temperature at onset of symptoms. Of the patients 81% had onset of symptoms when the temperature was less than 15C, and 67% of torsion cases occurred in the winter and spring. The authors suggest that there may be an etiological role in the pathogenesis of acute testicular torsion.

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2006 Biennial Meeting of the International Children’s Continence Society 

I encourage you to read the 11 articles (pages 2593–2640) in this issue presented at the 2006 meeting of the ICCS held in Antalya Turkey, September 14–17.