Clinical outcomes of the tunnelized-facial artery myomucosal island flaps in the oral cavity and comparison with cutaneous flaps in an animal model

Objective: This study aims to evaluate the clinical efficacy of tunnelized-facial artery myomucosal island flaps (t-FAMMIF) in reconstructing mucosal defects following oral cancer surgery and compare the characteristics between mucosal and cutaneous flaps. Methods: A total of 23 patients who underwent t-FAMMIF reconstruction were enrolled and monitored for functional recovery and complication resolution. Using propensity score matching, 20 cases were paired with a cohort of patients receiving cutaneous flaps (n=20 per group). Sensory function was assessed using the Semmes-Weinstein monofilament test and two-point discrimination tests, while motor function was evaluated with the Water Swallowing Test. Facial nerve function was assessed by House-Brackmann grading scale, wireless surface electromyography, and FaceGram software. Mouth opening was measured by maximum inter-incisal opening. Additionally, to explore the mechanisms underlying differential functional recovery, mucosal and cutaneous flaps were compared in a beagle dog model, with subsequent histological analysis. Results: Compared to the cutaneous flap group, the t-FAMMIF group exhibited superior aesthetic and sensory outcomes, with facial nerve dysfunction and trismus largely resolved by 6 months. Histological analysis in the animal model revealed that mucosal flaps preserved minor salivary glands and exhibited significantly reduced scar formation, providing a tissue-level explanation for the enhanced sensory recovery observed clinically. Conclusion: T-FAMMIF is an effective option for reconstructing small to moderate mucosal defects. Compared to cutaneous flaps, it provides advantages including superior aesthetic results, enhanced sensory recovery, minimized scarring, and preservation of salivary gland function.