Smile Outcomes When Using Masseteric Nerve-based Nerve Transfers versus Direct Muscle Neurotization in Facial Palsy...

Area of Science:

• Neurosurgery
• Facial Reconstructive Surgery
• Microsurgery

Background:

• Weak smile presents a significant challenge in facial reconstructive surgery.
• Nerve transfer techniques offer a potential solution for restoring smile function.
• Masseteric nerve to facial nerve transfer is a specific surgical approach evaluated.

Purpose of the Study:

• To evaluate the outcomes of masseteric nerve to facial nerve transfers for smile restoration.
• To compare the efficacy of nerve transfer with direct muscle neurotization (DMN).
• To assess functional improvements using validated scoring systems.

Main Methods:

• Retrospective cohort study of 20 patients over a 6-year period (2016-2021).
• Comparison between nerve transfer and DMN groups.
• Outcomes assessed using Sunnybrook, Ackerman Smile Index, and Terzis scores.
• Statistical analysis via Wilcoxon sign rank and Mann-Whitney U tests.

Main Results:

• Nerve transfers significantly improved overall Sunnybrook scores, lip elevation, and open mouth smiles (P<0.05).
• No significant difference in resting symmetry between pre- and postoperative states.
• Nerve transfer outcomes were comparable to DMN, with a trend towards better lip elevation with nerve transfer (P=0.047).

Conclusions:

• Nerve transfer neurotization of smile-mimetic muscles is effective, improving facial mimetic function and smile.
• Outcomes are comparable to DMN, with nerve transfer showing an advantage in lip elevation.
• Nerve transfer is a preferred option for patients with more severe smile weakness.