Imaging study of position correlation between kidney and colon under supine and prone positions

Objective:To explore the position relationship between kidney and colon under supine and prone positions,and judge the possibly increased risk of colon injury during percutaneous nephrostomy in prone position comparing with that in supine position.Methods:The data of CT and CTU of 20 left kidneys and 13 right kidneys from 30 patients(CT was taken in supine position,CTU in prone position) were analyzed retrospectively.The horizontal and vertical distances from kidney and colon to vertebral body,the shortest distance between ipsolateral kidney and colon,and the distance between colon and puncturing line of PCN in supine and prone positions were measured respectively.The position changes of kidney and colon,and the relative movement between them in supine and prone positions were detected.Results:Vertical distances of left kidney at supine and prone positions were(8.35±14.6) mm and(-3.71±13.8) mm,vertical distances of left colon were(23.1±21.7) mm and(12.23±18.7) mm respectively,with statistical differences.Vertical distance of right kidney at supine and prone positions had not statistical differences.The distances from left colon to the puncturing line at supine and prone positions were(15.4±16.2) mm and(11.05±14.9) mm respectively,with statistical differences,however,it had no statistical differences on right.Conclusions:Ventral displacement appeared for both kidneys and colon in prone position,however,the relative position between two organs has no obvious changes when position changes from supine to prone.The risk of colon injury doesn't increase during percutaneous nephrostomy in prone position comparing with that in supine position.