The effects of rectal cancer surgery on the anatomical localisation of ureters – a prospective observational study

Introduction: Anatomical changes after surgery and fibrotic adhesions increase the organ laceration risk, including that of the ureter, in recurrent cases and secondary operations. The aim of this study was to investigate the changes in the anatomical localisations of the ureters via computed tomography urography in patients undergoing rectal cancer surgery. Material and methods: The study involved prospectively collected data on the changes of ureteral location preoperatively and postoperatively in patients with operated rectal cancer. Distances (mm) of ureters determined midline in the computed tomography urogram phase. Results: A total of 18 patients were included. The mean distances between the right (R1 ) and left (L1 ) ureters and the mid-vertebral line before the surgery were 30.9 ±5.4 mm and 34.5 ±9.9 mm, respectively. The postoperative distances between them (R2 and L2 ) were 26.4 ±9.1 mm and 29.5 ±9.9 mm, respectively. The R2 measurement showed that 83.3% (15/18) of the right ureters had deviated medially, whereas 16.7% (3/18) of them had deviated laterally. The L2 measurements showed that 88.8% (16/18) of the left ureters had deviated medially, whereas 11.2% (2/18) of them had deviated laterally. The differences between the preoperative and postoperative measurements of the right and left ureter positions were 4.5 ±9.2 mm and 4.9 ±4.6 mm, respectively, with the displacement in the left ureter being statistically significant (p ≤ 0.001). Conclusions: Rectal cancer surgery causes medially deviated changes in the positions of the ureters.