A Photogrammetric Method of Measuring the Volume of Facial Swellings

I T IS desirable from various points of view to be able to measure quantitatively the volume of facial swellings in order to follow their development and to determine objectively their magnitude and duration. Such a measuring method would be of value when judging how the various etiological and pathogenetic factors influence postoperative edema, infectious swellings, edema resulting from local anesthetics, and so forth. A method of this kind, applicable to the jaw area, has, so far as we know, not yet been described. The method of recording volume changes of the body seems on the whole to be little used. An example, however, of a technic which has been employed, especially in physiology, is the plethysmographic method described by Lewis and Grant (1925) and Prinzmetal and Wilson (1935). For measuring rapid volume changes, a so-called impedance plethysmograph can be used. This method is based on the fact that the impedance of an extremity, for example, is under certain measuring conditions a function of its volume (Nyboer, Bagno, and Nims, 1943). The authors did not consider this or any similar methods appropriate for their case, since such methods are concentrated on volume variations of short duration, and since practical difficulties are encountered when applying them to the jaw. Photogrammetric methods were considered more suitable when dealing with facial volume mensuration, mainly because the measuring can be effected without any noteworthy influence on the object. In medicine and dentistry, photogrammetry has been made use of by Lacmann (1950), Berghagen (1951), Adams-Ray and Hjelmstrbm (1951), and others. Volume measurements of the direct type, as used in the experiments reported here, do not seem to have been previously applied to biologic objects, but have been used for quite different objects, for example, coal heaps, and so forth (Hallert, 1949). The purpose of the investigation was to make a practical test of the photogrammetric measuring method for the determination of facial swellings, to elaborate this method, to demonstrate as far as possible its accuracy, and to apply the results to cases of postoperative swelling.