The facial soft tissue thickness related facial reconstruction by ultrasonographic imaging: A review

The facial soft tissue thickness is crucial for facial reconstruction. Ultrasound is one method to evaluate facial thickness. There are two main modes of ultrasound that can be used for measurement: A-mode and B-mode. Because of its advantage, B-mode is frequently used in many recent studies. The factors that contribute to the varying results of facial soft tissue thickness are classified as method error and biological factors. The following factors should be considered when designing a study: subject type, subject posture and facial expression, ultrasound machine, ultrasound mode, transducer type, frequency, gel type and application, transducer orientation, landmark selection, and thickness measurement. According to the results of previous research, the main biological factors that likely affected facial thickness are sex, age, body mass index, and ancestry. However, there is still insufficient evidence to conclude how the thickness differs among various methods of measurement and which method produces the best results for facial reconstruction. Future ultrasonographic imaging research associated with facial thickness should determine the accuracy of the facial reconstruction to compare with other techniques and evaluate the gold standard of the facial reconstruction. Furthermore, the standardized landmarks and ultrasonographic imaging of each landmark should be clarified for consistency across the populations.