Setting the speed limit: a pilot study of the rate of serum creatinine decrease after endoscopic valve ablation in neonates

PURPOSE

In neonates with a posterior urethral valve serum creatinine is increased. It decreases after successful relief of obstruction. Clinicians consider urinary diversion if serum creatinine remains increased. However, the optimal rate of decrease of serum creatinine is not defined. We generated useful data on the rate of serum creatinine decrease in neonates with a posterior urethral valve by introducing the idea of a prediction curve.

MATERIALS AND METHODS

We reviewed the medical charts of 15 consecutive children treated for a posterior urethral valve in the neonatal period at our institute between 2002 and 2007. The 11 children with a delayed diagnosis of a posterior urethral valve were excluded from analysis. Serial serum creatinine levels in the cohort of 15 patients were analyzed to estimate 1) the rate of decrease after valve ablation and 2) the time needed to achieve a nadir.

RESULTS

One child died of renal insufficiency on day 10 of life and was excluded from study. Serum creatinine attained a nadir at about age 6 months but 73% of the total decrease occurred within the first 2 months of life, which was also equal to a 45% decrease from the peak values recorded soon after birth. The rate of decrease did not appear to be influenced by the peak values. Children with normal peak creatinine or intercurrent problems did not follow the trend.

CONCLUSIONS

The rate of decrease in serum creatinine in the first few months of life may provide useful information on the adequacy of valve ablation.

Management of urethrocutaneous fistula following hypospadias repair

Urethrocutaneous fistulas complicating hypospadias repair appear a common problem. There appears less data in the literature regarding the risk and management of recurrent fistulas. A retrospective review of urethrocutaneous fistulas complicating hypospadias repair was performed to evaluate their aetiology, management and outcome. Between 1993 and 2003, 1,753 patients had a hypospadias repair at our institution. Overall 123 (7%) boys developed a fistula, although detailed information was available on 117 patients only. Median age was 3.5 years at the time of fistula repair; 13% had anterior, 57% had middle and 30% had posterior hypospadias. The most common primary surgical procedure was a Durham Smith two-stage repair in 29% (n = 34), followed by a Tubularised Incised Plate urethroplasty in 19% (n = 22) and an Onlay in 14% (n = 16). Thirty-one (27%) patients developed a recurrent fistula, 9 (29%) of which recurred following a second repair. None recurred after a third repair. The risk of a recurrent fistula after an initial distal fistula repair was 12.5% and after a posterior fistula was 62% (chi(2) = 15.4, P = 0.001). Use of a stent, suture type, numbers of fistula and closure attempts did not influence the recurrence rate. Undiagnosed distal obstruction was thought to be related to 27 of 117 first fistula repairs (23%) and 4 of 31 second fistula repairs (13%). The risk of recurrent urethrocutaneous fistula was increased in those boys with a posterior fistula, following a simple repair or when there was evidence of distal urethral obstruction.

A method to assess posterior urethral valve ablation

PURPOSE

There are few published reports addressing the assessment of posterior urethral valve ablation. This study was performed to provide a ratio to measure successful treatment of posterior urethral valves.

MATERIALS AND METHODS

A total of 35 patients with posterior urethral valves were treated by a single surgeon between 1995 and 2004. Of these patients 23 were younger than 1 year at diagnosis and were selected for this study. A urethral ratio was calculated by dividing the posterior urethral diameter by the anterior urethral diameter. A total of 31 males undergoing cystography for urinary tract infections were evaluated as normative controls. The urethral ratio was also measured and calculated for these patients.

RESULTS

Median patient age was 1.5 months. In 13 patients preoperative cystograms were available and in 20 patients postoperative cystograms were available for review. Measurements were made of the posterior urethral and anterior urethral diameters. Median preoperative ratio in 13 patients was 8.6. This ratio decreased postoperatively to 3.1 in 15 patients who only required 1 ablation and 8.0 in 5 patients who required a second ablation. After a second ablation the ratio decreased to 3.1. The 5 cases requiring a second ablation were initially managed by cystoscopy and a flexible electrode. None of the patients treated initially with a resectoscope required a second ablation. Urethral ratio was 2.6 in 31 normal males undergoing cystogram for investigation of a urinary tract infection.

CONCLUSIONS

Calculating urethral ratio in patients with posterior urethral valves allows objective measurement of the technical success of valve ablation.

Congenital abnormalities of the urogenital tract in association with congenital vertebral malformations

There is a close link between the embryological development of the musculoskeletal system and all other main organ systems. We report a prospective series of 202 patients with congenital vertebral abnormalities and document the associated abnormalities in other systems. There were 100 boys and 102 girls. In 153 there were 460 associated abnormalities, a mean of 2.27 abnormalities for each patient. Intravenous pyelography was carried out on 173 patients (85.6%) and ultrasonography on the remaining 29 (14.4%). Patients with genitourinary anomalies were more likely to have musculoskeletal (p = 0.002), gastrointestinal (p = 0.02) and cardiac abnormalities (p = 0.008) than those without genitourinary involvement. A total of 54 (26.7%) had at least one genitourinary abnormality, the most frequent being unilateral renal agenesis. There was urinary obstruction in six (3%). There was no association between genitourinary abnormality and the place of birth, parental age, birth order, level of spinal curvature, or the number, type and side of spinal anomaly. There was, however, a statistically significant association (p = 0.04) between costal and genitourinary abnormalities. The incidence of genitourinary abnormalities (26.7%) was similar to that of previously reported series. The diagnosis of a congenital vertebral abnormality should alert the clinician to a wide spectrum of possible associated anomalies most of which are of clinical importance.

Congenital abnormalities of the urogenital tract in association with congenital vertebral malformations

There is a close link between the embryological development of the musculoskeletal system and all other main organ systems. We report a prospective series of 202 patients with congenital vertebral abnormalities and document the associated abnormalities in other systems. There were 100 boys and 102 girls. In 153 there were 460 associated abnormalities, a mean of 2.27 abnormalities for each patient. Intravenous pyelography was carried out on 173 patients (85.6%) and ultrasonography on the remaining 29 (14.4%). Patients with genitourinary anomalies were more likely to have musculoskeletal (p = 0.002), gastrointestinal (p = 0.02) and cardiac abnormalities (p = 0.008) than those without genitourinary involvement. A total of 54 (26.7%) had at least one genitourinary abnormality, the most frequent being unilateral renal agenesis. There was urinary obstruction in six (3%). There was no association between genitourinary abnormality and the place of birth, parental age, birth order, level of spinal curvature, or the number, type and side of spinal anomaly. There was, however, a statistically significant association (p = 0.04) between costal and genitourinary abnormalities. The incidence of genitourinary abnormalities (26.7%) was similar to that of previously reported series. The diagnosis of a congenital vertebral abnormality should alert the clinician to a wide spectrum of possible associated anomalies most of which are of clinical importance.

Congenital adrenal hyperplasia: preliminary observations of the urethra in 9 cases

PURPOSE

Congenital adrenal hyperplasia is the most common cause of androgen mediated virilization of the genitourinary tract in females. In our study relative lengths of the internal genital duct structure were compared with the degree of virilization of the external genitalia.

MATERIALS AND METHODS

The records of 9 consecutive female patients with a median age of 2.6 years with congenital adrenal hyperplasia were studied. There were 4 normal females with a median age of 7.4 months who had a voiding cystourethrogram for urinary tract infection used as controls. The patients with congenital adrenal hyperplasia were stratified into groups as having mild, moderate or severe virilization based on preoperative photographs of external genitalia. By lateral voiding cystourethrograms the length of the proximal urethra, vagina and urogenital sinus was measured and standardized against the femoral metaphysis. The relative length of these internal genital structures was compared to the degree of virilization of the external genitalia.

RESULTS

There were 4 cases classified as normal, and 2 mildly, 4 moderately and 3 severely virilized. The urogenital sinus appeared to lengthen, with increasing virilization of the external genitalia. There was no trend for the proximal urethra to shorten with increasing virilization. The vagina also seemed to shorten with increasing virilization.

CONCLUSIONS

Our results suggest that the vagina enters the urogenital sinus at a fixed distance from the bladder neck. With increasing virilization, the majority of urethral lengthening occurs primarily distal to the vaginal opening, that is urogenital sinus lengthening.