A prospective radiological anatomical study of the variations of the position of the colon in the left pararenal space.

Percutaneous puncture of the kidney allows direct access to the pyelocalicial cavities. The posterior approach of this retroperitoneal organ can be complicated of transcolic punctures due to the postrenal position of the colon. A prospective radiological anatomical study of the relationship between the left kidney and the descending colon was undertaken. One hundred computed tomograms of adult subjects were obtained from which the anatomy of the left perirenal area was determined: the descending colon is more frequently behind the kidney in the young females. Two main factors determinants of this situation are: 1) colon ontogenesis in relation to the attachment of the primitive mesocolon, permitting a 'fixed' left colon, or 'moving' left colon at the end of a long mesocolon, allowing it to pass behind the kidney; 2) a mechanical factor whereby the accumulation of perirenal fat with increasing age may be a limiting factor in lateral displacement of the colon.