Received: 11 October 2019
Accepted: 3 December 2019
First Online: 10 January 2020
Ethics approval and consent to participate
: The protocol was reviewed and approved by the Local Ethics Committee of Ain Shams University. It ruled that no formal ethics approval was required in this retrospective study, and so no reference number was given by the IRB.
: Although the manuscript of our retrograde study contains no individual information and the images are unidentifiable, yet, a written consent for publication was obtained for these cases.
: The authors declare that they have no competing interests.