Anatomical Basis for Lip Reconstruction: The Role of the Modiolus

Objective The aim of this study was to establish the anatomic basis for functional upper and lower lip reconstruction with locoregional flaps. Design, Setting, and Participants This article is an anatomic fresh cadaver study. Results For lower lip reconstruction, the modified Bernard-Webster and Karapandzic flaps preserve the modiolus, buccinator, zygomaticus major muscle, and buccal branches of the facial nerve. The Bernard-Webster flap allowed for a larger oral aperture despite a larger defect, but required transection of the lower lip depressors and orbicularis oris. For upper lip reconstruction, the reverse fan flap preserves the modiolus and its muscle attachments. The reverse Karapandzic flap required transection of the lower lip depressors, buccinator, and the zygomaticus major. Conclusions and Relevance Locoregional flaps remain the workhorse for lip reconstruction. This study provides the anatomic basis for the modiolus and its muscular attachments that permit techniques such as the Bernard-Webster flap and the Karapanzic flap to achieve functional lip reconstruction with innervated and denervated tissue.