Pearls for perfecting the mastoid interpolation flap

Helical rim ear defects can present a reconstructive challenge to the Mohs surgeon. Multiple options exist including wedge excision, helical rim advancement flaps, bilobed flap, and grafts, to name a few. Wedge excision of the ear may result in a noticeable anteverted, smaller ear, and disrupts auricular cartilage with the possibility of chondritis and excess pain. Helical rim advancements can result in anteversion of the ear and a smaller lobule. Mastoid interpolation flaps, which are also called retroauricular to auricular flaps, can be a useful alternative in patients who are willing to return for a second procedure. They are easy to perform and can result in a highly aesthetic reconstruction in which the ear size and form are maintained. The donor skin comes from an area that is hidden from view and heals with minimal complications. We present our suggestions for performing these reconstructions. Ways to optimize results, potential pitfalls, and postoperative care instructions are discussed. Step by step videos are included with this manuscript.