Ureteropelvic Junction Obstructions: Is Side a Prognostic Factor?

Background: Ureteropelvic junction obstructions (UPJOs) occur more frequently on the left than on the right side. Among patients diagnosed during the neonatal period, those with left-side UPJO have a more severe course than those with right-side UPJO. Aim: This study examined clinical advances in the surgical management of right and left symptomatic UPJOs preoperatively and postoperatively, based on a retrospective analysis of cases. Patients and Methods: In this retrospective clinical trial, 650 patients were evaluated at the time of diagnosis and at surgery. Results: Left-side UPJO was diagnosed in 66.1% of patients (P = 0.017). The median age of the patients at surgery for left- and right-side UPJO was 1.5 and 4.2 years, respectively (P = 0.001). At the preoperative evaluation, the ratio of parenchymal thickness (RPT) on the UPJO side versus the contralateral side was 0.55 +/- 0.3 and 0.7 +/- 0.3 for patients with left-side and right-side UPJO, respectively (P = 0.029). RPT during the first postoperative year was 0.83 +/- 0.2 for patients treated on the left side and 0.9 +/- 0.3 for those treated on the right side (P = 0.25). The respective values at 3 years postoperatively were 0.8 +/- 0.3 and 0.9 +/- 0.2 (P = 0.09). The preoperative kidney function value in the left-side group was 42.5 +/- 13.4, which declined to 39.52 +/- 15.8 at the 3-year follow-up examination. In the right-side group, preoperative kidney function was 38.8 +/- 16.1, which increased to 40.2 +/- 13.2 at 3 years postoperatively. Both the decline and improvement were significant (both P = 0.006). Conclusions: Those with left-side UPJO had a more severe course than those with right-side UPJO.