Polnak, John F.
Delate, Thomas
Clark, Nathan P.
Article History
First Online: 21 April 2018
Compliance with ethical standards
:
: No authors have any potential conflicts of interest to report.
: All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards.
: A waiver for obtaining informed consent was obtained from the Kaiser Permanente Colorado Institutional Review Board prior to performing this retrospective study.