Purpose: Our goal was to assess the incidence of retropsoas positioned large or small bowel in the population and to examine factors predisposing to its formation.
Method: The presence of retropsoas positioned bowel was retrospectively studied in 1,852 abdominal CT examinations of 1,055 men and 797 women, 648 younger and 1,204 older than 50 years. All examinations were considered normal or demonstrated findings that were unrelated to the position of the bowel.
Results: Retropsoas positioned colon (RPC) was observed in 51 (2.8%) cases for the ascending and 45 (2.3%) for the descending colon. RPC appeared more frequently in younger (< 50 years) than older patients and in individuals with decreased amount of retroperitoneal fat. Retropsoas position of small bowel loops was observed in 11 (0.6%) patients, all exhibiting paucity of retroperitoneal fat.
Conclusion: Because of its prevalence, retropsoas positioned bowel should be considered when performing percutaneous diskectomy or other interventional procedures in the posterior retroperitoneum.