Predictors of Recoverability of Renal Function after Pyeloplasty in Adults with Ureteropelvic Junction Obstruction.

ABSTRACT

BACKGROUND: This study aimed to identify factors predicting the recoverability of renal function after pyeloplasty in adult patients with ureteropelvic junction obstruction. METHODS: We retrospectively reviewed 138 adults with unilateral renal obstruction-induced hydronephrosis and who underwent Anderson-Hynes dismembered pyeloplasty from January 2013 to January 2016. Hydronephrosis was classified preoperatively according to the Society for Fetal Urology (SFU) grading system. All patients underwent Doppler ultrasonography, excretory urography, computed tomography, and technetium-99m-diethylenetriamine pentaacetic acid radioisotope (99mTc DTPA) renography before and after surgery. Renal resistive index (RRI) and 99mTc DTPA renography were repeated at 1, 3, 6, and 12 months. RESULTS: Multivariate analysis identified age, renal pelvic type, SFU grade, preoperative RRI, decline of RRI, and renal parenchyma to hydronephrosis area ratio (PHAR) as independent predictors of renal function recoverability after pyeloplasty. However, preoperative RRI and RRI decline were not significantly associated with recoverability of renal function in patients aged >35 years. Lower preoperative RRI, greater decline in RRI, higher PHAR, lower SFU grade, and extrarenal pelvis were associated with greater improvements in postoperative renal function. CONCLUSIONS: Preoperative differential renal function cannot independently predict the recoverability of postoperative renal function in adult patients with unilateral renal obstruction-induced hydronephrosis. SFU grade, renal pelvic type, PHAR, preoperative RRI, and decline in RRI were significantly associated with the recoverability of renal function in adult patients aged <35 years, while only SFU grade, renal pelvic type, and PHAR were significantly associated with renal function recoverability in patients aged ≥35 years. Renal function recovery was better in patients younger than 35 years when compared with older patients.