Dear Editors,

We would like to thank Dr. Mihmanli for his comments on our paper “2021 Update on the Urinary Tract Dilation Classification System: Clarifications, Review of the Literature, and Practical Suggestions” [1]. We do acknowledge that there was an error in the manuscript, namely that for Urinary Tract Dilation (UTD) P3, the anterior posterior (AP) renal pelvic diameter should be 15 mm. It was not our intent to change this value to 10 mm.

In addition, Dr. Mihmanli makes very valid points about how the AP diameter changes with hydration status, degree of bladder filling, and patient positioning [2].