title: Retro-renal colon: role in percutaneous access.
abstract: BACKGROUND
  Upper urinary tract is accessed for various procedures. The maximum numbers of procedures are carried out in prone position. Perforation of the colon is a well-known complication. The incidence of retrorenal colon varies from 10-20% in prone position, but the chances of injury is around <1%. These facts lead us to review the occurrence of retrorenal colon. The CT scan is imaging test of choice.
  
  
  OBJECTIVE
  The aim of this study was to find out the occurrence of retrorenal colon at our centre and potential risk of injury to colon when kidney is punctured at various levels by percutaneous route.
  
  
  METHODS
  It is a hospital-based descriptive type of observational study. We reviewed CT abdomen in supine and prone position in patients with different problems from January 2013 to December 2013. Inclusion and exclusion criteria applied. Colon posterior to the line as described by Prassopoulos and coworkers is regarded as retrorenal colon and being at risk.
  
  
  RESULTS
  A total number of 700 patients were included, 350 each in supine and prone position. Patients had CT scan as a part of workup for pain abdomen in 27% cases, calculus disease in 25% cases, carcinoma bladder in 16% cases and rest were of different diagnoses. Retrorenal colon was found in 2% patients in supine and 6.8% patients in prone position.
  
  
  CONCLUSIONS
  Considering the low incidence, the sample size in our study is small. We recommend multicentric large population-based study to establish the true incidence of retrorenal colon and chances of injury to colon.
authors.affiliation: Department of Urology and Renal Transplantation, SMS. Medical College, Jaipur, India, sharmadrgovind@yahoo.com.
authors.forename: Govind
authors.initials: G
authors.lastname: Sharma
authors.forename: Dharmendra Kumar
authors.initials: DK
authors.lastname: Jangid
authors.forename: S S
authors.initials: SS
authors.lastname: Yadav
authors.forename: Rajeev
authors.initials: R
authors.lastname: Mathur
authors.forename: Vinay
authors.initials: V
authors.lastname: Tomar
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D003106:Colon / Q000002:abnormalities* / Q000293:injuries*; D000013:Congenital Abnormalities / Q000453:epidemiology; D005260:Female; D006801:Humans; D007223:Infant; D007431:Intraoperative Complications / Q000209:etiology* / Q000517:prevention & control*; D007674:Kidney Diseases / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D009403:Nephrostomy, Percutaneous; D056888:Patient Positioning; D014057:Tomography, X-Ray Computed; D055815:Young Adult