Soft-tissue facial asymmetry before and after orthognathic surgery: application of a new 3D protocol

Introduction: Skeletal Class III patients often present a major facial asymmetry. In the current investigation, a quantitative method to assess 3D facial asymmetry was applied to an orthognathic surgery patient to quantify possible postsurgical modifications. Methodology: Soft-tissue facial scans of a 20-year-old man with skeletal Class III, candidate to orthognathic surgery, were collected in the pre-surgery stage and 6, 12, 24 months post-surgery with a stereophotogrammetric system. Soft tissue asymmetry was calculated in the facial thirds according to a published protocol (J Craniomaxillofac Surg 2017;45(1):76-81), and the relevant time-related modifications described. The results were also compared to normal values from a group of 23 control subjects (10 men, 13 women, mean age 26) by using z-scores. Results: The longitudinal analysis of the soft-tissue facial asymmetry showed a marked difference in the analysed time points: orthognathic surgery did reduce facial symmetry in the present patient. The comparison between the patient and the control subjects by using z-scores highlighted a clear difference in all-time points: the patient with facial dysmorphia had a higher degree of asymmetry than healthy subjects. Conclusion: The measurements of soft-tissue facial asymmetry using 3D optical digitisers can provide clinically useful information. The graphical representation of results can help in the patient’s understanding of the treatment phases, thus increasing compliance.