Craniofacial deformities are common facial abnormalities that can significantly affect patients' appearance and oral function, leading to profound impacts on their psychological and quality of life. Autologous fat grafting has been used since the early 20th century for facial filling, offering advantages such as using the patient's own tissues, minimal risk of rejection, and providing a natural appearance. Therefore, it has become a popular method in plastic surgery and widely used to treat various types of facial deformities. However, the technique also presents clinical challenges, as the transplanted fat cells need sufficient blood supply in the new location to survive and maintain their volume. During the process, a portion of the transplanted fat tissue without blood supply will be absorbed. Generally, the absorption rate of transplanted fat tissue varies from 30% to 70% depending on factors such as location, surgical technique, time, and individual differences, leading to unstable outcomes. Factors affecting the survival rate of fat particles after transplantation include infection, poor blood supply in the recipient area, age, physique, nutrition, mental state, and the duration of the deformity. Shallow depressions have a lower absorption rate, while deeper ones have a higher absorption rate. Postoperative immobilization of the transplanted fat area is necessary to rebuild blood circulation. However, there is no literature reporting the exact impact of these factors on the absorption rate of fat grafts. Therefore, it is suggested that autologous fat grafting should be performed using the "small amount multiple times" method for timely correction.

In addition to being influenced by surgical techniques and individual differences, a more significant issue is the lack of accuracy in assessing the effectiveness of this technique. Previous evaluation methods include subjective assessment and objective evaluation methods such as cephalometric measurements. However, these methods have various degrees of inaccuracy in evaluating soft tissue volume changes. The emergence of the 3dMD face system (3dMD) (3dMD Inc, Atlanta, Ga) technology is expected to solve this problem. 3dMD technology, full name 3D facial scanning imaging technology, uses binocular vision principles to rapidly capture three-dimensional data of the face, providing high-precision facial morphology information. It is accurate, fast, and radiation-free, and literature suggests it is the preferred method for evaluating the results of facial soft tissue volume recovery surgery. The application of 3dMD technology can help achieve precise measurements of facial volume before and after fat grafting, providing a powerful tool for studying fat absorption rates.

This study is an observational study that will use 3dMD technology to accurately measure changes in facial volume before and after autologous fat grafting by scanning the patient's face in three dimensions. This will provide accurate fat absorption or retention rates and study the impact of individual factors on treatment outcomes through regression analysis. This will help better understand the effectiveness of autologous fat grafting technology and provide a scientific basis for the treatment of craniofacial deformities.