MATERIAL and METHODS: Eighty patients (male/female: 42/38) with a mean age of 45 years were included in this retrospective study. An imaginary line passing through the tangential to the posterior cortex of the vertebral body was drawn at the intervertebral disc level (line a). Perpendicular to this line were two lines (line b) drawn from the ureters.The lines of the cortex, where ?line a? was cut (point c), were also drawn from the contralateral ureter (line d). The distances between ?lines b and d? were measured. Another line was drawn from both ?c? points to the ipsilateral ureters (line x). The angle between ?lines a and x? was measured (angle x).

RESULTS: The right kidney hilus was inferior to the left kidney hilus. A significant negative correlation was observed between line band lumbar level (r=?0.95). The average length of ?line b? at the lower lumber levels was 2.1 cm. Moreover, a positive correlation was found between ?angle x? and lumbar level (p<0.05). The ?angle x? increased from 38° to 80° with the decrease in lumbar levels. In addition, the ?angle x? was significantly higher in male patients (p<0.05) than in female patients. No significant correlation was found between ?line d? and lumbar level.

CONCLUSION: CT is an illumination modality that could elucidate the relationship between intervertebral disc and ureter preoperatively and could visualize the retroperitoneum. Keywords : Ureter, Ureter injury, Computed tomography, Spinal surgery