Contributions of 3D Photography and Stereophotogrammetry to the Evaluation of Facial Symmetrization Through Botulinum Toxin Injections, in Patients With Peripheral Facial Palsy

"This is a prospective, single-center study. The main objective of our study will be to objectively evaluate the improvement of facial symmetry after botulinum toxin injection on the face in patients suffering from sequelae of peripheral facial paralysis. A secondary objective will be to assess the utility of 3D photography and stereophotogrammetry to detect and quantify facial changes relevant to this type of treatment. The number of patients included in the study is expected to be 15 at minimum. Our study will rely on 3D photographs taken with the Vectra H2 Imaging System camera device (Canfield Scientific, Inc., Fairfield, New Jersey), which will be captured before and 3 weeks to 1 month after botulinum toxin injection into the facial muscles. Various analyses of static and dynamic symmetry will be performed using the Vectra software: bi-pupillary line angle / bi-commissural line angle, superposition of healthy and pathological sides followed by RMS (root mean square) calculation, analysis of pre- and post-injection skin displacement vectors.

The results of these analyses will allow conclusions to be drawn regarding the objective efficacy of botulinum toxin injections for facial symmetrization in patients with peripheral facial paralysis, as well as to adapt injection patterns based on the severity of facial paralysis."