This study aimed to assess the functional and esthetic outcomes of a chimeric innervated buccinator myomucosal-submental island flap (BMM-SIF) for large composite lower lip reconstruction.

This retrospective study included five patients who underwent lower lip tumor resection and BMM-SIF reconstruction at the Hospital of Stomatology, Sun Yat-sen University, between August 2021 and February 2023. Lip function was evaluated using water leakage, cheek puffing tests, and superficial electromyography. Lip appearance was observed using photographs and evaluated through subjective interviews. Donor-site conditions, including facial symmetry and mouth opening, were monitored.

All the BMM-SIFs survived. Drooling was the main complication observed shortly after surgery. The water leakage test showed complete oral competence for liquid holding in the 7th month; however, moderate air leakage was present in two patients. Electromyography revealed myoelectric signals from the innervated buccinator at the recipient site. Facial expression and food intake were typically managed. The shape and projection of the vermilion were harmonious and satisfactory for each patient. Neither microstomia nor mouth opening limitation was observed, with an average inter-incisor distance of 37.25±4.4 mm.

Chimeric motor-innervated BMM-SIF effectively reconstructed large full-thickness lower-lip defects with satisfactory functional and esthetic outcomes.