Accessory or additional renal arteries show no relevant effects on the width of the upper urinary tract: a 64-slice multidetector CT study in 1072 patients with 2132 kidneys

Objective

The aim of this study was to find out on an unselected patient group whether crossing vessels have an influence on the width of the renal pelvis and what independent predictors of these target variables exist.

Methods

In this cross-sectional study, 1072 patients with arterially contrasted CT scans were included. The 2132 kidneys were supplied by 2736 arteries.

Results

On the right side, there were 293 additional and accessory arteries in 286 patients, and on the left side there were 304 in 271 patients. 154 renal pelves were more than 15 mm wide. The greatest independent factor for hydronephrosis on one side was hydronephrosis on the contralateral side (p<0.0001 each). Independent predictors for the width of the renal pelvis on the right side were the width of the renal pelvis on the left, female gender, increasing age and height; for the left side, predictors were the width of the renal pelvis on the right, concrements, parapelvic cysts and great rotation of the upper pole of the kidney to dorsal. Crossing vessels had no influence on the development of hydronephrosis. Only anterior crossing vessels on the right side are associated with widening of the renal pelvis by 1 mm, without making it possible to identify the vessel as an independent factor in multivariate regression models.

Conclusion

The width of the renal pelvis on the contralateral side is the strongest independent predictor for hydronephrosis and the width of the renal pelvis. There is no link between crossing vessels and the width of the renal pelvis.Obstructions of the ureteropelvic junction (UPJ) can be caused by intrinsic or extrinsic factors 1]. Although there are no studies of this to date, crossing the UPJ by an aberrant crossing vessel is considered the most important 2] of the extrinsic factors 3]. Crossing vessels, which are thought to cause from 40% to over 50% of the extrinsic UPJ obstructions in adults 4, 5], are located ventral more often than dorsal to the UPJ. These are usually normal vessels of the lower pole segment 4, 6–9], which can be divided into additional renal arteries arising from the aorta, and accessoric renal arteries arising from branches of the aorta 10, 11]. The primary surgical therapy of choice is endoscopic endopyelotomy 12]. The success rate of 89–90% 12, 13] is thought to be noticeably poorer in patients with crossing vessels 12, 13]; however, this is not undisputed 14, 15]. Be that as it may, to prevent bleeding complications it is necessary to be familiar with the vascular situation around the UPJ prior to the procedure 3, 16–18]. CT angiography is used for this purpose, as it is highly accurate, quick to perform and shows all relevant anatomical structures in relation to one another 3, 19, 20]. The objective of this study was to determine whether or not there are vascular morphological patterns or other factors that influence the width of the renal collecting system, regardless of the definitions of hydronephrosis.