Further application of the bilobed flap: the split bilobed flap for reconstruction of composite posterior auricular and mastoid defects.

In this article a modified bilobed flap from mastoid and lateral neck skin for reconstruction of complex defects of the posteromedial surface of the auricle and mastoid skin, with the preservation of the retroauricular sulcus, is described. Reconstruction of the postero-medial auricular surface has almost never been a concern for reconstructive surgeons. It is in fact a shaded area with little aesthetic relevance and direct closure, skin grafting and even secondary healing are used for skin cancer defects repair. Also mastoid skin defects can be repaired with simple techniques such as skin grafts or transposition flaps from the remaining mastoid skin or from the neck. On the other hand, cancers involving the postero-medial auricular surface, the retroauricular sulcus and the mastoid skin require wide and deep resections that involve the posterior auricular muscles and reach the perichondral and periosteal surfaces. Direct closure with undermining, if feasible, will obliterate the retroauricular sulcus causing asymmetry with the contralateral ear and, if defects are cephalad will impair the possibility of wearing spectacles, thus leaving functional and aesthetic impairment. Transposition flaps from the remaining mastoid skin, due to the lack of skin laxity, are not feasible because the donor site cannot be closed. Two patients, both affected by basal cell carcinoma involving the posteromedial auricular surface and the mastoid skin have been treated with this flap. In both cases the use of the modified bilobed flap described in this article allowed preservation of the retroauricular sulcus and closure of the donor site. Scars were hidden along minimal tension lines and the possibility of wearing spectacles along with sensitivity all over the reconstructed area were maintained.