Ureteropelvic junction obstruction (UPJ) due to congenital crossing of the renal vessels (CRV): Comparison of the pre- and postoperative features of UPJO with and without CRV

We evaluated the differences in demographic characteristics of patients with and without underlying crossing renal vessels (CRVs) operated for unilateral symptomatic ureteropelvic junction obstruction (UPJO). We identified the features of patients who had undergone open, laparoscopic and robotically assisted laparoscopic pyeloplasty at our institution from July 2000 to January 2021. The ratio of renal parenchymal thickness (RPT; ratio between the kidney with UPJO and the healthy kidney), pelvic diameter and kidney functions were recorded. A total of 641 patients were operated for UPJO; 448 were male (69.8%) and 193 (30.1%) were female; 257 had right-side (40%) and 384 (60%) left-side disease. Fifty-eight patients (9%) were found to have CRV (operated on to treat CRV). The age at diagnosis was 6.51 ± 5.09 years in the CRV (+) group and 1.82 ± 1.37 years in the CRV (−) (p < 0.001). The age at surgery was 8.00 ± 4.71 and 4.27 ± 3.54 years, respectively (p < 0.001). At the time of diagnosis, the RPT measurement was significantly better in CRV (+) compared to CRV (−) group (0.71 ± 0.2 vs. 0.64 ± 0.23, p = 0.043) and initial renal functions were 45.53 ± 8.99% and 42.99 ± 11.65% in CRV (+) and (−) groups respectively. At the time of surgery, the RPTs were 0.60 ± 0.24 and 0.63 ± 0.21 in CRV (+) and (−) groups and these values were also correlated with split renal functions (36.28 ± 15.81% and 41.80 ± 14.26%, respectively). Renal functions were significantly decreased in CRV (+) group (p = 0.027). Significant parenchymal improvements were noted during the first postoperative year. The RPTs were 0.71 ± 0.2 and 0.77 ± 0.19 in the CRV (+) and CRV (−) groups, respectively (p = 0.27) in that time; the improvements continued to increase to postoperative third year (0.74 ± 0.20 and 0.78 ± 0.19 respectively; p = 0.939). In patients with CRVs, renal functions seemed to be preserved in the early stages, however it should be kept in mind that sudden obstruction and loss of kidney function might develop in the follow up period.