Abstract

S. Vaggers*, R. Menzies-Wilson, S. Folkard, E. Balai, S. Runa, K. Atalar, B. Berry, C. Bastianpillai, S. Graham, P. Pal

Objective: Patients with ureteric stones can pass their stones before their ureteroscopy (URS) resulting in a negative URS. We introduced pre-operative CT KUBs for patients listed for URS for a ureteric stone with the aim of reducing the negative URS rate. We also measured the radiation dose of the CT KUBs and URSs. Methods: We retrospectively audited all patients with ureteric stones listed for an elective URS across three audit periods. We recorded whether they had a CT KUB within one week of surgery and the result of this CT KUB and whether they had a negative URS. Results: Our audit returned a total of 108 patients across three audit periods. The rate of spontaneous stone passage was significantly higher for stones ≤7mm (30.99%) compared for stones >7mm (8.11%) (p=0.0079). Over the study period the use of pre-operative CT KUB within one week of surgery for stones <7mm increased from 16.67% to 50%. At the same time the percentage of patients with a negative URS reduced from 11.9% to 4.00%. The radiation dose of a CT KUB was 9.89 mSv (SD 2.59) compared 2.82 mSv for a URS (SD 3.28) (p=<0.0001). Conclusion: Pre-operative CT KUB is an effective way to reduce negative URS rate. Low dose CT KUBs (<3.5mSv) are comparable to the radiation dose of a URS