Computer Imaging Software for Profile Photograph Analysis
Travis T. Tollefson, MD; Jonathan M. Sykes, MD
Arch Facial Plast Surg. 2007;9(2):113-119.
Objectives To describe a novel calibration technique for photographs of different sizes and to test a new method of chin evaluation in relation to established analysis measurements.
Design A photograph analysis and medical record review of 14 patients who underwent combined rhinoplasty and chin correction at an academic center. Patients undergoing concurrent orthognathic surgery, rhytidectomy, or submental liposuction were excluded. Preoperative and postoperative digital photographs were analyzed using computer imaging software with a new method, the soft tissue porion to pogonion distance, and with established measurements, including the cervicomental angle, the mentocervical angle, and the facial convexity angle.
Results The porion to pogonion distance consistently increased after the chin correction procedure (more in the osseous group). All photograph angle measurements changed toward the established normal range postoperatively.
Conclusions Surgery for facial disharmony requires artistic judgment and objective evaluation. Although 3-dimensional video analysis of the face seems promising, its clinical use is limited by cost. For surgeons who use computer imaging software, analysis of profile photographs is the most valuable tool. Even when preoperative and postoperative photographs are of different sizes, relative distance comparisons are possible with a new calibration technique using the constant facial landmarks, the porion and the pupil. The porion-pogonion distance is a simple reproducible measurement that can be used along with established soft tissue measurements as a guide for profile facial analysis.
Figure 2. Illustration of the soft tissue equivalents of cephalometric landmarks (A); the cervicomental angle is formed by a line tangent to the submentum (from the menton [Me] to the subcervicale [SC]) and a line tangent to the neck intersecting at the SC (the innermost point between the submental area and the neck)4 (B); the mentocervical angle is defined by a line from the pronasale (Pn) or nasal tip to the soft tissue pogonion (Pog") intersecting with the submental tangent (Me to SC) (C); and the facial convexity angle5 is defined as the intersection of a line from the glabella (G) to the subnasale (Sn) with a line from the Sn to the Pog" (D). Po" indicates porion.
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