Neurotization Preferences in Smile Reanimation: A Discrete Choice Experiment

Background: Common donor nerve options in smile reanimation include ipsilateral trigeminal motor or contralateral facial nerve branches. Neurotization preference may be influenced by multiple factors, whose relative importance remains poorly understood. In this article, decision-making in smile reanimation is assessed using a stated preference model. Methods: Qualitative interviews with facial palsy patients identified five relevant attributes for study: smile type ("smile when biting" versus "smile spontaneously" as proxies for trigeminal versus cross-facial neurotization), number of operations, success rates, complication rates, and side effects. Community volunteers (n = 250) completed a discrete-choice experiment relevant to free muscle transfer for smile reanimation. Preoperative and postoperative states were demonstrated through video vignettes, together with explanation of surgical risks, consequences, and benefits. Attribute importance was modeled using hierarchical Bayes estimation. Results: Two hundred forty-one responses met quality controls. Attribute importance ranked as follows: chance of success, 37.3 percent; smile type, 21.4 percent; side effects, 13.9 percent; complication rates, 13.8; and number of operations, 13.6 percent. All attributes significantly correlated with decision making (p < 0.0001). An aggregate response model revealed most participants (67.6 percent; standard error, 3.0 percent) preferred smile reanimation by cross-facial (assuming a success rate of 80 percent) as opposed to ipsilateral trigeminal motor branch neurotization. When the success rate for cross-facial neurotization was reduced below 67 percent, trigeminal neurotization was preferred. Conclusions: Despite a higher risk of failure, most respondents preferred a cross-facial as opposed to trigeminal neurotization strategy for smile reanimation. These findings highlight the complexity of decision-making and need for individualized risk tolerance assessment in the field of facial reanimation.