Facial paralysis measurement with a handheld ruler.

Background: Evaluation of the severity of facial paralysis deformity and the effectiveness of reconstructive surgery requires a measurement tool that is practical and simple enough for daily use. It should be able to objectively measure facial asymmetry at rest and the amount of facial movement during expression. The authors present and assess a simple measurement technique that is readily usable in the clinic. Designed to evaluate smile reconstruction, the technique can be used to evaluate other parts of the paralyzed face, such as the eye, nose, and forehead.

Methods: A standardized handheld ruler measuring technique is described for the assessment of the position and the movement of five points marked on the lips. The measured points are used to characterize the position of the mouth at rest and the movement that occurs with smiling. The technique uses two transparent rulers that are held in the examiner's hand. Using this technique, two experienced examiners separately measured the rest position of 21 unilateral facial paralysis patients twice, creating 84 sets of measurements. Accuracy was assessed by simultaneously measuring the movement of the commissure and mid upper lip during smiling on 10 normal persons using both handheld ruler and a proven technique, the facial reanimation measurement system.

Results: The average intraclass correlation coefficients for interrater and intrarater reliability exceed 0.89. The mean difference between the handheld ruler and facial reanimation measurement system measurements was 1.7 mm.

Conclusion: The handheld ruler technique is simple, reliable, and accurate, providing useful measurements for the evaluation of facial paralysis reconstructions.