[1] Johns Hopkins Sch Med, Dept Urol, Baltimore, MD 21287 USA
[2] Vet Adm Greater Los Angeles Healthcare Syst, Dept Surg, Los Angeles, CA USA
[3] Univ Calif Los Angeles, Sch Med, Dept Urol, Los Angeles, CA 90024 USA
[4] Stanford Univ, Sch Med, Dept Urol, Stanford, CA 94305 USA
[5] San Diego Naval Hosp, Dept Urol, San Diego, CA USA
[6] Med Coll Georgia, Div Urol, Augusta, GA 30912 USA
[7] San Francisco Vet Adm Med Ctr, Dept Surg, Urol Sect, San Francisco, CA USA
[8] Univ Calif San Francisco, Sch Med, Dept Urol, San Francisco, CA 94143 USA