Facial motion analysis of acid burn victims—Development of a new facial motion impairment index

Objectives Evaluation of facial movement is necessary for the assessment of motor deficits and planning reconstructive surgery in facial burns. Clinicians recognise the need for an accurate and reproducible method of functional assessment. We propose a new facial functional impairment index (FFII) for assessing facial motor dysfunction due to severe burn injury and provide inter/intra-patient comparison for documenting rehabilitation. Methods The maximal static response assay (MSRA) was used to compare facial movement in 20 acid burn victims with 20 control subjects. Data compiled from 12 soft tissue landmarks was used to quantify rest and dynamic asymmetry, anatomic and non-anatomic motion and calculate the FMII. The Katz score, Nottingham index and number of affected aesthetic units provided insight into FFII efficacy. Results Patients with greater aesthetic disfigurement demonstrated significantly poorer anatomic function (c = 0.62; p = 0.03) as well as larger global facial functional impairment (c = 0.52; p = 0.08). Conclusion Acid burns caused severe asymmetry and functional impairment. The FFII is a composite score of global function based on a reproducible method of data collection and it differentiated between acid burn victims and provided objective comparative measures. Software automation, integration of video and 3D data, appropriate graphical and pictorial depiction of variables and measurements, and further research into the accuracy of FFII as a marker of clinical recovery and assessment of function in facial burns, will enhance future clinical applications and potentially aid surgical reconstruction.