A radiological study on the anatomical proximity of the ureters and the cervix

In order to evaluate risk factors for anatomical proximity between the cervix and the ureters the distance between the ureters and the cervix was measured in 499 computerized tomography (CT) studies at the most dorsal reflection of the ureters. The relationship between the ureter-cervical distance and the presence of pelvic pathology was assessed by correlation tests and regression analysis. Of the 499 CT studies, 252 demonstrated radiographic pathologies. Among abnormal scans, 126 (50%) involved cervical pathology. At least one ureter was within 0.5 cm of the cervix in 3.6% of patients with normal CT scans and in 10.3% of patients with cervical pathology. Overall, the right ureter was significantly closer to the cervix than the left (2.0 +/--0.8 cm vs. 2.2 +/- 1.0 cm, p < 0.05). In cases were the pathology was limited to the cervix, the right ureter was more distant than the left (2.0 +/- 0.6 cm vs. 1.7 +/- 0.6 cm, p < 0.05). The distance between the ureters and the cervix was inversely correlated with the lateral diameter of the cervix (r=0.18, p < 0.001) and its anterior-posterior diameter (r=0.11, p < 0.001). Age did not correlate with the distance of the ureters from the cervix (r=0.002, p=N.S). In conclusion, approximately 10% of patients with cervical pathology can be expected to have a ureter proximate less than 5 mm from the cervix. For patients with cervical pathology undergoing a planned hysterectomy, preoperative measurement of cervical-ureteric distance may be warranted. In these circumstances intra-operative measures to protect the ureter and ascertain its integrity may be invaluable.