Determinants of hydronephrosis and renal injury in patients with myelomeningocele.

Renal injury is a major potential complication of patients with neurogenic bladder impairment. There are many clinical, radiological and urodynamic factors that are widely available and that may aid in predicting which patients are at risk of renal injury. This study aims at achieving an objective statistical analysis of these multiple risk factors. We have applied this statistical analysis in a prospective manner to 215 patients with myelodysplasia and neurogenic bladder impairment. Potential risk factors in the lower urinary tract include bladder capacity, contractility and dyssynergia. Each of these factors was assigned a numerical score of 0 to 3, which was correlated with the presence of vesicoureteral reflux. The upper urinary tracts in these patients were assigned a numerical score according to the degree of radiological changes observed. These results then were tested with a stepwise regression analysis using p equals 0.05 as the significance level. In this analysis significant determinants of vesicoureteral reflux included a change in bladder shape, the presence of uninhibited contractions and the presence of dyssynergia. Renal deterioration was noted, and it was predicted by the presence of vesicoureteral reflux, a high ureteral pressure profile and dyssynergia. We conclude from this clinical study that risk of renal injury is present in these children. We also conclude that the risk can be predicted by urodynamic and radiological criteria and that these data can be correlated and analyzed using statistical methodologies.