Journal Pre-proof Duplex systems: top-down or bottom-up approach? D.J.B. Keene, R. Subramaniam PII: S1477-5131(20)30058-9 DOI: https://doi.org/10.1016/j.jpurol.2020.03.005 Reference: JPUROL 3400 To appear in: Journal of Pediatric Urology Received Date: 4 March 2019 Accepted Date: 11 March 2020 Please cite this article as: Keene D, Subramaniam R, Duplex systems: top-down or bottom-up approach?, Journal of Pediatric Urology, https://doi.org/10.1016/j.jpurol.2020.03.005. This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. © 2020 Journal of Pediatric Urology Company. Published by Elsevier Ltd. All rights reserved.