To develop a technique that helps avoid colonic injury during percutaneous nephrolithotomy (PCNL) in these patients.

PCNL was prospectively performed in a cohort of adults with renal stones in a horseshoe kidney (HSK). PCNLs were done using a standardized technique in prone position in all patients. The colon was radiologically delineated by injecting air—through a catheter in the anal canal—to help localize its position in relation to the pelvicalyceal system (PCS). Patients were observed in hospital for 48 hours postoperatively to detect any potential complications related to the PCNL or to the colon insufflation modification.

Thirteen adult patients (11 men and 2 women) with renal stones in a HSK were included in the study. The colon was well radiologically delineated with air in all cases. The PCS was successfully accessed, subcostally, with a single access at the upper calyx in 11 cases and multiple accesses in 2 cases. The colon was in the way of the puncture in 2 cases in which we used a more medial access and the colon was successfully avoided. Stones were completely removed during the PCNL in 11 of the 13 cases (84.6%). One case necessitated intraoperative blood transfusion. No other complications were reported by any of the patients who were discharged home after 48 hours.

Colonic radiological delineation technique is helpful in accessing the PCS quickly, saving the colon, and causing no discomfort to patients with renal stones in a HSK.