Cortical adaptation staging system a new and simple staging for result evaluation of functioning free-muscle transplantation for facial reanimation

Background: Movement-associated cortical reorganization occurs in patients after functioning free-muscle transplantation (FFMT), which is reinnervated by different neurotizers. Aiming to evaluate the process of recovery of the reinnervated muscle, we defined the cortical reorganization into 5 stages. This staging system has been applied during the past 25 years at our center with great convenience and accessibility. Methods: A standardized evaluation method for assessing the recovery after FFMT to reanimate the paralyzed face with at least a 1-year follow-up was applied. The evaluation included the following 5 stages: no movement, dependent movement, independent movement, and spontaneous movement with and without involuntary movement. Reliability of this technique was assessed by 3 examiners, who each evaluated the smiles of 30 unilateral facial paralysis patients 4 times, creating 360 sets of measurements. Results: The intraclass correlation coefficients for interrater and intrarater reliability exceeded 0.929, which is considered excellent and reliable. Conclusions: Chuang's Cortical Adaptation Staging System is simple, quick, and accurate in evaluating patients after FFMT reanimation of the paralyzed face with no additional tools.