Fayyaz Ahamed 1, Ashwin S. Balakrishnan 1, Jorge Mena 1, Benjamin N. Breyer 1, 2, Nathan M. Shaw 1, ⁎ 
1 Department of Urology, University of California San Francisco, San Francisco
2 Department of Epidemiology and Biostatistics, University of California San Francisco, San Francisco
⁎Address correspondence to: Nathan M. Shaw M.D., Clinical Instructor of Urology, Genitourinary and Reconstructive Surgery Fellow, University of California, San Francisco.Clinical Instructor of Urology, Genitourinary and Reconstructive Surgery FellowUniversity of CaliforniaSan Francisco