Three-dimensional objective evaluation of facial palsy and follow-up of recovery with a handheld scanner

Abstract

Clinicians need accurate, reproducible, fast, and cost-effective grading systems to determine facial functions. There is currently no internationally accepted objective method to report the loss of function at the onset of facial paralysis and subsequent recovery. Our study aimed to test a three-dimensional handheld light scanner's efficacy for grading facial paralysis and monitoring recovery. Sixty-one healthy volunteers (28 men and 33 women) aged between 20 and 75 years (mean 36.4±11.9 years old) and 22 patients with facial palsy (10 male and 12 female patients) aged between 12 and 77 years (mean 47.6±19.7 years old) were included in the study. The healthy individuals' and patients' facial scans were performed with a three-dimensional handheld scanner during different facial expressions at 3-month intervals. The asymmetry and intensity degree of each facial expression were determined in terms of the root mean square. After facial paralysis, a significant larger asymmetry value (1.2±0.4mm vs. 2.0±0.8mm and p<0.05) was determined as compared to the control group, while a significant smaller intensity value (2.3±1.2mm vs. 1.7±0.9mm and p<0.05) was observed. At the end of 3 months, both parameters showed a tendency to recover. Our findings suggest that three-dimensional morphological analyses may be an effective method to grade facial palsy. However, our data need to be confirmed by larger cohort size and more extended follow-up periods.