Salivary gland tumor is one of the most common tumors in oral and maxillofacial regions. The diagnosis and treatment of salivary gland tumors had been a clinical characteristic project in Peking University School and Hospital of Stomatology since long time ago. Here we introduced the research progress in diagnosis and treatment of salivary gland tumors during the past 10 years. Among 7 190 cases of salivary gland tumors treated in this institution, 4 654 cases (64.7%) were benign, and 2 536 (35.3%) were malignant, with benign ∶ malignant ratio of 1.84 ∶ 1. Parotid was the most common location, followed by minor salivary gland and submandibular gland, while sublingular gland tumor was seldom seen. The proportion of minor salivary gland tumor was relatively high. Among 1 874 cases with primary malignant tumors, the cases with T3 and stage Ⅲ accounted for only 9.6% and 10.3%, respectively, which indicated that there was shortcoming in the T classification and clinical stage formulated by Union for International Cancer Control (UICC), and further revision was required. The 5, 10, and 15 year survival rates of 1 637 cases with postoperative follow-up were 93.1%, 87.2% and 79.3%, respectively, which were much higher than those we reported 30 years ago. The improvement of treatment results was related to more widely used combined treatment with surgery and postoperative radiotherapy, and the increase in patients with early stage. Adenoid cystic carcinoma was the malignant tumor with high rate of distant metastasis. The 5 and 10 year survival rates of the patients with pulmonary metastasis were 76.2% and 51.8%, respectively, which indicated that the pulmonary metastatic carcinomas developed slowly. Recurrent rate of carcinoma ex pleomorphic adenoma was 46.7% after single treatment of sur-gery, while it decreased to 27.5% after combined theraphy with surgery and radiotherapy, indicating that postoperative radiotheraphy could reduce the recurrent rate effectively. The normal myoepithelial cells had the inhibiting role in the invasion and metastasis of carcinoma ex pleomorphic adenoma. The evaluation of integrity of myoepithelial cells surrounding the tumor mass is helpful to understand the invasiveness of the tumors. The new surgical modalities such as extracapsular resection and partial sialoadenectomy were used in treatment of benign tumors of parotid gland and submandibular gland with advantages of decreased tissue damage and preservation of glandular function. Application of digital surgical techniques such as mixed reality combined with surgical navigation and real-time three-dimensional holograms in the surgical treatment of parotid gland tumors showed the benifits of more safety and precision, and less tissue da-mage.
Humans ; Salivary Gland Neoplasms/pathology* ; Carcinoma, Adenoid Cystic/therapy* ; Adenoma, Pleomorphic/therapy* ; Neoplasm Staging

Objective:To assess the feasibility and application of mixed reality combined with surgical navigation technology in parapharyngeal space tumor surgery, and to provide a reference for the development and promotion of this technology.Methods:In this study, retrospective data collection was conducted on 16 patients with parapharyngeal space tumors who were treated at the Department of Oral and Maxillofacial Surgery, Peking University School and Hospital of Stomatology from June 2020 to June 2023. The patient′s age was (39.6±17.8) years, with 4 males and 12 females. Mixed reality combined with surgical navigation technology was utilized to assist physicians in the treatment of these patients. Mixed reality combined with surgical navigation technology was used to assist physicians in treatment of these patients. The application steps included acquisition of image data, processing of image data [three-dimensional (3D) reconstruction, image fusion, and virtual surgical design], development of surgical navigation plan, connection of mixed reality and navigation system, automatic registration and intraoperative guidance and validation. In the preoperative plan, landmark points were placed on the virtual tumor and surrounding important structures reconstructed using digital software, serving to guide the localization of crucial anatomical structures. Intraoperative positioning deviation, surgical time, intraoperative blood loss, and postoperative complications were recorded and analyzed to evaluate the clinical application effectiveness of mixed reality combined with surgical navigation technology.Results:With the assistance of mixed reality combined with surgical navigation technology, 16 patients successfully underwent tumor resection. All patients were accurately diagnosed preoperatively by 3D reconstruction and image fusion technology, and a comprehensive preoperative plan was formulated; intraoperatively, mixed reality combined with surgical navigation technology was utilized for the localization of important structures. The average localization deviation of 38 landmark points during the operation were (4.43±1.96) mm, with 62% (26/42) of the points having a deviation of ≥0 and<5 mm. The average duration of the operation was (149.6±53.9) min and the blood loss was 70 (45, 150) ml. The average postoperative follow-up was 16 months, and five patients experienced postoperative complications involving facial paralysis, hoarseness, and choking.Conclusions:Mixed reality combined with surgical navigation technology can achieve the three-dimensional visualization of oral and maxillofacial anatomical structures to achieve precise preoperative diagnosis. During surgery, the technology can real-time display the relationship between soft tissue tumors and the surrounding important anatomical structures, guide surgical operation, and enhance the safety of surgery.

Objective:To evaluate the outcome of Augmented reality technology in the recognizing of oral and maxillofacial anatomy.Methods:This study was conducted on the undergraduate students in Peking University School of Stomatology who were learning oral and maxillofacial anatomy.The image da-ta were selected according to the experiment content,and the important blood vessels and bone tissue structures,such as upper and lower jaws,neck arteries and veins were reconstructed in 3D(3-dimension-al)by digital software to generate experiment models,and the reconstructed models were encrypted and stored in the cloud.The QR(quick response)code corresponding to the 3D model was scanned by a net-worked mobile device to obtain augmented reality images to assist experimenters in teaching and subjects in recognizing.Augmented reality technology was applied in both the theoretical explanation and cadaveric dissection respectively.Subjects'feedback was collected in the form of a post-class question-naire to evaluate the effectiveness of augmented reality technology-assisted recognizing.Results:In the study,83 undergraduate students were included as subjects in this study.Augmented reality technology could be successfully applied in the recognizing of oral and maxillofacial anatomy.All the subjects could scan the QR code through a connected mobile device to get the 3D anatomy model from the cloud,and zoom in/out/rotate the model on the mobile.Augmented reality technology could provide personalized 3D model,based on learners'needs and abilities.The results of likert scale showed that augmented reality technology was highly recognized by the students(9.19 points),and got high scores in terms of forming a three-dimensional sense and stimulating the enthusiasm for learning(9.01 and 8.85 points respective-ly).Conclusion:Augmented reality technology can realize the three-dimensional visualization of impor-tant structures of oral and maxillofacial anatomy and stimulate students'enthusiasm for learning.Be-sides,it can assist students in building three-dimensional space imagination of the anatomy of oral and maxillofacial area.The application of augmented reality technology achieves favorable effect in the recog-nizing of oral and maxillofacial anatomy.