The facial plethysmograph: a new instrument to measure facial swelling volumetrically.

A critical review of methods used to evaluate postoperative facial swelling is presented. A new, noninvasive method using a feeler arm to trace and measure facial contours is described. The overall accuracy and reproducibility of this method was tested by measuring acrylic "mock swellings." The results suggest that the method was accurate to within 5% in measuring swellings of known volume. The reproducibility of replicate measures also showed a low level of error (3.3%). This device may provide a unique method for the systematic study of treatments designed to minimize postoperative facial swelling.