Evaluation of a New Measurement Tool for Facial Paralysis Reconstruction

Abstract

Evaluation of facial movement, including distance and direction, is essential for anyone interested in facial paralysis reconstruction. The authors' goal was to develop a measurement system that is simple, uses commercially available equipment, takes little time, and provides meaningful and accurate measurements. This technique is called the facial reanimation measurement system. It involves placing dots around the patient's mouth and video recording the patient performing maximal effort smiles. Using a video editing program, one frame showing the patient at rest is overlaid with a second frame showing the patient's smile. This overlaid image is imported into Adobe PhotoShop, where measurements are obtained using tools available in the program. Twenty patients were used to test interrater and intrarater reliability of the facial reanimation measurement system. The accuracy of the measurement process was tested by comparing 10 known distances and angles with those obtained using the facial reanimation measurement system. Both intrarater and interrater reliability of the distance and angle measurements are highly accurate, with intraclass correlations greater than 0.9. The facial reanimation measurement system is accurate to within 0.6 mm and 2.0 degrees when compared with a "known" distance and angle. The facial reanimation measurement system has been used to measure smile movements of more than 200 patients and has been demonstrated to be valuable for detecting changes of facial movements over time. This system is simple and economical and only requires 20 minutes to perform. Although the authors demonstrated evaluation of smile movement, the system may be used to evaluate other movements, such as mouth puckering, eye closure, and forehead elevation.