An ideal method for evaluating facially disfigured patients should combine morphologic analysis and dynamic evaluation. We analyzed a 17-year-old male patient with sequelae of facial trauma caused by a motorcycle accident (Fig. 1). He underwent multiple reconstructive procedures, but a disfigured face remains and further operations are needed.
First, we conceived three-dimensional facial avatars using two different approaches: (1) a moving low-cost RGB-D device for low-resolution results (Kinect; Microsoft Corp., Redmond, Wash.), and (2) a single-shot method taken from multiple high-resolution cameras synchronized and configured in stereoscopic pairs. This system creates an animatable three-dimensional facial model that resembles a real person. The process is divided into three steps: (1) acquisition, (2) retopology, and (3) texture transfer. [See Figure, Supplemental Digital Content 1, which shows an overview of the pipeline. (Left) Input RGB and depth maps. (Second from left) Three-dimensional mesh reconstruction. (Second from right) Alignment of the scanned mesh with our template. (Right) Texture computation, http://links.lww.com/PRS/B283.]
The first deals with the three-dimensional data gathering, which allowed us to create the subject virtual face model. The second (retopology) is the conversion process to a “ready-to-animate” model, fitting the template of a generic mesh to the acquired three-dimensional mesh. Last, the texture transfer method computes the new texture, which is adjusted to the avatar’s mesh.
Thermographic measurements were taken posteriorly. The thermography camera used was a FLIR SC7000 (FLIR Systems, Wilsonville, Ore.) with a hot metal colored lens filter that was previous configured to a 30° to 40°C temperature range. The subject sat on a chair at a distance of 1.5 m from the camera. He was asked to perform four facial expressions: facial expression at rest, with eyes closed, with eyes wide open, and while smiling.
Data management was performed with Altair 5.91.010 software (FLIR Systems). An analysis mask was established over the facial areas of interest: (1) right forehead, (2) left forehead, (3) right orbit, (4) left orbit, (5) nose, (6) right labial commissure, (7) left labial commissure, and (8) mouth. For each area, the mean temperature and its standard deviation were calculated, as were the maximum and minimum values (Table 1).
In addition to a detailed analysis of the facial dynamics, three-dimensional models analyzed with MeshLab (“Alessandro Faedo” Institute of Information, National Research Council, Pisa, Italy) allowed for a morphologic study and direct measurements. This avatar showed persistent ectropium and a significant change in vertical height of the palpebral fissure on the left side (Fig. 2). In the frontalis muscle contraction exercise, we have observed asymmetry and gross brow hairline distortion. (See Figure, Supplemental Digital Content 2, which shows frontalis muscle contraction, http://links.lww.com/PRS/B284.) When ordering palpebral voluntary closure, the patient could not completely close his left eyelid. The problems seem to affect mainly the upper and middle thirds of the face, as good excursion of the oral commissures was seen.
Concerning thermographic analysis, when comparing the measures to a control group (28 normal subjects), he showed a persistent tendency for contralateral thermal asymmetries, with the highest values of surface temperature on the right side, and the highest values on the right forehead area. [See Figure, Supplemental Digital Content 3, which shows average temperature and standard deviation (area 1) and left (area 2) forehead areas during the four facial expressions (patient 1). The hatched bars represent the mean values and standard deviations of the control group for the same task, http://links.lww.com/PRS/B285.] Surface temperature reduction on the left labial commissure was also seen. (See Figure, Supplemental Digital Content 4, which shows smiling analysis, http://links.lww.com/PRS/B286.) These findings were probably a consequence of muscular damage, fibrosis, facial nerve paralysis, and decrease of the regional blood flow. These technologies could have a place in the management of facially disfigured patients, and further studies are needed.
The patient provided written consent for the use of his images.
None of the authors has a financial interest in any of the products or devices mentioned in this article.
Ricardo Horta, M.D.
Rita Valença-Filipe, M.D.
Ricardo Nascimento, M.D.
Alvaro Silva, M.D.
José Manuel Amarante, M.D., Ph.D.
Department of Plastic, Reconstructive, and Maxillofacial Surgery, and Burn Unit
Centro Hospitalar de São João
Porto Medical School
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