Identifying the position of an ear from a laser scan: the significance for planning rehabilitation

Laser scanning techniques are used to plan the construction of prosthetic ears as dimensional measurements between anthropometric points can be accurately measured on a screen image. The aim of this study was to determine if these techniques could be used to assess the position of ears on the face. Computer-generated images were created from laser scans of 20 subjects. Frames of reference were constructed by locating a series of anthropometric points on the face from which three orthogonal planes were constructed. A central reference point was identified at the intersection of the three orthogonal planes. Dimensional measurements were made between anthropometric points on the ear and the reference planes. The differences between anthropometric points and the reference planes on the left and right sides of the face were small. It was possible to describe the location of points three-dimensionally with respect to a central reference point. The development of frames of reference and a central reference point would appear to offer many advantages in the assessment and description of ear position for patients requiring reconstruction with prostheses.