The Prevalence of Retrorenal Colon Among Computerized Tomography Scanned Patients

Abstract

Background: percutaneous nephrolithotomy (PCNL) is regarded as the treatment of choice for most renal stones larger than 2cm. Colon injury is one of the rare and preventable complications during PCNL. The rare and unusual location of the colon behind the kidney (retrorenal colon) is an anatomical predisposing factor and other factors that can result in colon perforation during PCNL. Aim: To evaluate the prevalence of retrorenal and posterolateral colon and among CT scanned patients.Patients and methods: one thousand CT scanned patients of all ages and both sexes were included and their CT images were evaluated prospectively at the CT scan center at Azadi Teaching Hospital for the presence of retrorenal colon and the relation of the colon to different parts of the kidney. Results: In this study, 1000 CT scanned patients of different ages and both sexes were included. There were 522 males and 478 females; their ages ranged from 6 to 85 years. The overall prevalence of retrorenal colon was 7.5% (6.3% in males and 8.7% in females). The prevalence of retro renal colon according to different ages was: at below 10 y was 16%, 11-20 years 8.3%, 21-30 y 5.9 %, 31-40 y 7.2 %, 41-50y 7.2%, 51-60y 11.2%, 61-70y 5.8% 71-80y 7.2% and at 81-90 y was 9%, and the differences regarding the ages and sexes were statistically not significant. The lower pole of the left kidney is the most common part involved by the retrorenal colon in 70.6%, while the right lowers pole by 12%, the left middle part by 10.6%, and bilateral lower poles by 6.6%. Conclusion: Locally, the prevalence of retrorenal colon is within the usual range with no sex or age predominance, and a pre-operative abdominal CT scan (native one) is a diagnostic one and is essential if left lower renal calyx is planned to be targeted to avoid colonic injury.