Non-reflux Group Research Articles

Upper-tract changes after treatment of posterior urethral valves.

This paper discusses the long-term sequelae in the upper urinary tract with respect to hydroureteronephrosis (HUN), vesicoureteral reflux (VUR), renal parenchymal disease, and their correlation with renal function in 84 boys with posterior urethral valves followed for 1 to 21 years. Thirty-one boys (39.3%) were adolescents or older at the time of review. The incidence of high-grade VUR (grade III or more) was 47.6% at presentation, and resolution following decompression of the lower urinary tract occurred in 38.7% of refluxing units. VUR was associated with a high incidence of chronic renal failure (CRF) (30%) on long-term follow up; however, 16% of non-refluxing patients also progressed to CRF. The incidences of renal parenchymal disease and persistent upper-tract dilatation in the non-refluxing group were 25% and 50% of renal units respectively. Gross HUN persisted in 12.3% of patients despite decompression and reconstructive surgery, with vesicoureteral junction (VUJ) obstruction being documented in 1 patient only. Moderate and mild upper-tract dilatation persisted in 31.6% and 43.9% of patients, respectively. Persistent gross HUN was associated with a very high incidence of CRF (92.3%), while 88.4% of those with persistent mild/moderate dilatation maintained normal renal function over a follow-up period ranging from 1 to 21 years. This study emphasizes the need for systematic evaluation to exclude VUJ obstruction and abnormal urodynamics as a cause of persistent HUN so that effective therapy can be instituted early to relieve back-pressure and to provide a low-pressure reservoir with effective emptying. In the absence of either of these causes, persistent ureterectasis after treatment is presumably due to secondary peristaltic failure as a consequence of ureteral fibrosis, ureteral tortuosity, or developmental dysplasia.

Urinary n-acetyl-beta-glucosaminidase as a screening technique for vesicoureteral reflux

Objective. To determine if urinary N-acetyl-beta-glucosaminidase (NAG) assays could be applied as a screening test for early detection of vesicoureteral reflux. Methods. Two hundred eighty-eight urine samples from children undergoing voiding cystourethrography (VCU) for a variety of urologic problems were assayed for N-acetylbeta-glucosaminidase using spectrophotofluorimeter techniques. Sample creatinine levels were also determined using an auto analyzer. The urinary NAG to creatinine ratio for each patient was then compared to their VCU results, which were interpreted independently of the assay values and graded according to the International Reflux Classification system. The NAG to creatinine ratios were then classified according to their grade of reflux, and the mean NAG levels, plus one standard deviation, were calculated for each as well as for the nonrefluxing controls. Statistical analysis was done with P values obtained by Student's t-test. Results. A total of two hundred thirty-two specimens were evaluable with ninety (38.8%) samples collected from refluxing patients and one hundred forty-tw o (61.2%) samples from nonrefluxers. The NAG levels standardized to urine creatinine revealed a mean value among refluxers of 15.514 μmol/g creatinine. This compared with a mean value of 14.611 μmol/g creatinine in the nonrefluxing group, with the difference being insignificant. When the mean NAG levels were compared for each grade of reflux to the nonrefluxing controls, only grade V had a significant elevation (44.561 μmol/g creatinine) above the nonrefluxers (P = 0.0001). Conclusions. With the exception of grade V vesicoureteral reflux, urinary NAG levels do not reliably detect the presence of reflux and therefore cannot be accurately applied as a screening test for detection of this common urologic problem.

Vesicoureteric reflux in children: prediction with color Doppler imaging. Work in progress.

Unlike gray-scale sonography, color Doppler ultrasonography allows reliable visualization of the ureteric jet phenomenon. A study was undertaken to determine whether any measurable parameter predicts the presence of vesicoureteric reflux. Measurements of mean urine jet velocity, longitudinal angle, transverse angle, and distance of the origin of the jet from the midline of the bladder were obtained on 31 infants and children (62 ureters) with a proved urinary tract infection. Of these measurements, only the distance of the ureteric orifice from the midline of the bladder was found to correlate with vesicoureteric reflux (mean distance in the reflux group, 10.25 mm +/- 2.40 (standard deviation [SD]); in the nonreflux group, 7.98 mm +/- 2.40 [P = .004]). The authors conclude that the more laterally positioned the ureteric orifice, the more likely it is to reflux. Color Doppler ultrasound measurement of the laterality of the ureteric orifice may be useful for predicting which children with a urinary tract infection would benefit from voiding cystourethrography.

Clinical significance of ureteric diameter on intravenous urography after spinal cord injury.

The ureteric diameter on IVU was compared with the MCU findings of reflux or lower urinary tract dysfunction in a group of patients followed up after spinal cord injury. A wide ureter was associated with reflux in 20%, but 8 normal sized ureters on IVU also refluxed--5 of them to a significant degree. In the non-refluxing group, wide ureters were noted more often in patients whose bladder pressures were high and wildly fluctuating than in those with normal bladder pressures. Similarly, the incidence of reflux was higher in patients with high bladder pressures and wild fluctuations of bladder pressure than in those with normal pressures. While a wide ureter on IVU should arouse suspicion that reflux or lower urinary tract dysfunction might be present, these conditions are not necessarily excluded by the finding of a ureter of normal size.