Does hydronephrosis after extravesical ureteral reimplantation deteriorate renal function?

Abstract

Purpose: We analyzed whether newly developed or aggravated hydronephrosis deteriorates differential renal function after extravesical ureteral reimplantation.

Materials and methods: We performed extravesical ureteral reimplantation in 93 patients with unilateral vesicoureteral reflux between January 2006 and December 2009. Excluding 3 patients with other combined disease, a retrospective cohort analysis of 90 consecutive patients was conducted. We performed ultrasonography before and 1 month after extravesical ureteral reimplantation, and dimercapto-succinic acid scan before and 6 months after extravesical ureteral reimplantation. Of the patients 83 underwent final dimercapto-succinic acid scan at 6 months postoperatively. We analyzed the preoperative studies and perioperative parameters to evaluate the factors affecting newly developed or aggravated hydronephrosis at 1 month, and decrease in differential renal function at 6 months after extravesical ureteral reimplantation.

Results: Newly developed or aggravated hydronephrosis was observed in 25 patients (28.4%) 1 month after extravesical ureteral reimplantation. Younger age at surgery was a risk factor (p = 0.003). Of the patients 23 showed improvement on ultrasound 6 months postoperatively. In 12 patients (15.7%) a decrease in differential renal function of more than 5% was observed 6 months postoperatively. Preoperative parenchymal reduction on dimercapto-succinic acid scan was the only significant factor (p = 0.008). There was no correlation between newly developed or aggravated hydronephrosis and final decrease in differential renal function (p >0.999).

Conclusions: Although newly developed or aggravated hydronephrosis after extravesical ureteral reimplantation is common, especially in younger patients, it is transient and does not affect differential renal function. A postoperative decrease in differential renal function without further urinary tract infection could develop when there is a parenchymal reduction on preoperative dimercapto-succinic acid scan.