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In this article, authors mainly introduce new digital technology in facial bone contouring surgery. In our experience, these new technologies are crucial in ensuring the satisfaction of surgical accuracy. Our previous studies have shown surgeons can use precise pre-operative design to reduce operative time, reduce bleeding during surgery. Additionally, augmented reality can enhance the perspective perception of surgeons combining virtuality and reality. What's more, robot-assisted surgical technology also has a strong application prospect in facial contouring surgery. In the future, the combination of soft tissue contouring surgery will make the facial bone contouring surgery safer and more effective.

This study aimed to investigate the feasibility and accuracy of osteotomy and distractor placement using a robotic navigation system in a model surgical experiment of mandibular distraction osteogenesis for hemifacial microsomia. Imaging data from 5 patients with Pruzansky-Kaban type II (IIa: 4; IIb: 1) mandibular deformities were used to print 3D models for simulated mandibular distraction osteogenesis. In the experimental group, a robot-assisted surgical navigation system was used to perform the surgery under robotic guidance following registration, according to the preoperative design. Conventional surgery was performed in the control group, in which the operation was based on intraoperative estimations of the preoperative design by experienced surgeons. The accuracies of the osteotomy and distractor placement were assessed based on distance and angular error. Osteotomy accuracy was higher in the experimental group than in the control group, and the distance error (t=9.311, P0.001) and angular error (t=5.385, P=0.001) were significantly reduced. The accuracy of distractor placement was also significantly higher in the experimental group, while the distance error (t=3.048, P=0.016) and angular error (t=3.524, P=0.024) were significantly reduced. The present results highlight the feasibility of robot-assisted distraction osteogenesis combined with electromagnetic navigation for improved surgical precision in clinical settings.

Background Traditional craniotomy relies on the surgeon's experience and can be complicated owing to excessive skull bone removal, undesirable brain tissue penetration, or severe bleeding. For craniotomy, we developed a robot system based on intraoperative cone-beam computed tomography image guidance and human-robot cooperative interaction, aiming to improve the safety and accuracy of surgery and reduce the labor-intensiveness of the procedure. Methods Intraoperative cone-beam computed tomography image guidance was adopt to improve the accuracy in our experiment. Craniotomy was performed using an interactive method based on human-robot collaboration, which could achieve a natural interactive method in accordance with surgeons' operating habits. The frequency-based method of contact distinction and the method of torque estimation were used to improve the safety of the designed robot. Results An animal experiment was conducted to verify the effectiveness of the robot system. During the drilling process, the position error was 0.92 ± 0.17 mm (upper surface) and 0.97 ± 0.11 mm (lower surface), and the angle error was 3.37 ± 1.43°. During the milling process, the position error was 1.06 ± 0.13 mm (upper surface) and 1.09 ± 0.09 mm (lower surface). The results showed that the system had sufficient precision and could better complete craniotomy with human-robot collaboration. In addition, with the feedback of multisensor information, the robot system could achieve a sufficient level of safety. Conclusions The robot system can achieve accurate positioning and safe user-friendly human-robot interaction, which solves problems encountered in the drilling and milling of craniotomy, meets clinical needs, and provides a new method for robot-assisted craniotomy.

To evaluate the feasibility, safety, and accuracy of the new man-machine interactive robotic system in model experiment. The implantation of the 8 to 10 bone screws over the skull model obtained from real patient's digital imaging and communications in medicine (DICOM), three-dimensional spiral computed tomography (CT) scans were taken. The end of the robotic arm was replaced with standard parts (including marker ball) for cone beam computed tomography (CBCT) scanning. The marker ball and marker pin were segmented and marked and exported via txt format. The position of the robotic end and model was obtained through the conversion of spacious position of standard parts and the executive end was replaced eventually. The water balloon was placed inside the skull model to imitate the dura mater and the destruction was documented for the system's safety. The system accuracy was evaluated by the error between the actual drilling position and the virtual plan and selection of 14 points of the skull window of milling pathway, monitored intraoperatively via Micron Tracker system and the overall skull window overlapped percentage via Mimics. Five model experiments were successfully performed with the average registration time of 3 minutes without destruction of balloon. The error of the outer table was 0.85 ± 0.45 mm, the inner table was 0.78 ± 0.49 mm, the line segment error of milling cutter was 0.93 ± 0.50 mm and the overall skull window overlapped percentage was 97.37% ± 0.78%. The system shows safety, accuracy, and reliability which can be an optional assistant method for craniotomy in the future.

Macrostomia is arare congenital craniofacial deformity that influences the appearance and function of patients. In most cases, it coexists with craniomaxillofacial deformities such as craniofacial microsomia (CFM). This study aimed to analyze the relationship between macrostomia and mandibular hypoplasia so as to facilitate the early detection and diagnosis of children with CFM. It included 236 patients diagnosed with CFM. All underwent facial expression analysis, multi-angle photography, computed tomography, and three-dimensional reconstruction of soft and hard tissues. The clinical classification was performed according to OMENS+. Spearman (rank) correlation analysis was used to analyze the relationship between the severity of macrostomia (C1 and C2) and the degree of mandibular involvement (M1, M2a, M2b, and M3), and the correlation among the components of OMENS+. Of the 80 cases of macrostomia (34%) reported, 72 cases (90%) were C1 and 8 (10%) were C2. The analysis of OMENS+ revealed significant correlations among OMENS+ components. Also, a high correlation was observed between macrostomia (C) and hypoplasia of the mandible (M) ( P = 0.002). Macrostomia was closely related to mandibular hypoplasia among children diagnosed with CFM. These results suggested that patients with macrostomia, who might also have craniofacial malformations caused by other first branchial arch anomalies, should be comprehensively physically examined for other syndromes.

Background Few clinical studies on robot-assisted surgery (RAS) for mandibular contouring have been reported. Objectives The aim of this study was to follow the long-term effectiveness and safety of RAS for craniofacial bone surgery. Methods This small-sample, early-phase, prospective, randomized controlled study included patients diagnosed with mandibular deformity requiring mandibular contouring surgery. Patients of both genders aged 18 to 30 years without complicated craniofacial repair defects were enrolled and randomly assigned in a 1:1 ratio by a permuted-block randomized assignments list generated by the study statistician. The primary outcomes were the positioning accuracy and accuracy of the osteotomy plane angle 1 week after surgery. Surgical auxiliary measurement index, patient satisfaction scale, surgical pain scale, perioperative period, and complications at 1 week, 1 month, and 6 months after surgery were also analyzed. Results One patient was lost to follow-up, resulting in a total of 14 patients in the traditional surgery group and 15 in the robot-assisted group (mean [standard deviation] age, 22.65 [3.60] years). Among the primary outcomes, there was a significant difference in the positioning accuracy (2.91 mm vs 1.65 mm; P Conclusions Compared to traditional surgery, robot-assisted mandibular contouring surgery showed improved precision in bone shaving, as well as higher safety. Level of Evidence: 2

This study aimed to explore correlations between mandible and ear deformities and quantitative volumetric relations between condylar structures and external ear in hemifacial microsomia. The authors reconstructed three-dimensional craniofacial models from 212 patients with unilateral hemifacial microsomia (the unaffected side as the controls). Patients were evaluated by Pruzansky-Kaban and Marx classification, and divided into 3 age groups (0-6, 7-12, and >12 years old). The mandible condylar structures, including condyle and the condylar skeletal unit, were selected (except the classification of the mandibular or ear deformities (M3)). Along with the external ear (except the classification of the mandibular or ear deformities (E4)), their volumes were measured and analyzed. Spearman correlation coefficient analysis was applied. There was a positive correlation between the mandible and ear deformities (r = 0.301, P

With the development of computer-assisted surgery, preoperational design is detailed in software. However, it is still a challenge for surgeons to realize the surgical plan in the craniofacial surgery. Robot-assisted surgery has advantages of high accuracy and stability. It is suitable for the high-stress procedures like drilling, milling, and cutting. This study aims to verify the feasibility for automatic drilling without soft tissues in model test based on an industrial robot platform.This study chose the data from digital laboratory in Shanghai 9th People's Hospital. The mandibular was reconstructed in software and surgical plan was also designed. Then, the coordinate data was input to the robot's software and matrix conversion was calculated by 4 marked points. The trajectory generation was calculated by inverse kinematics for target coordinates and robot coordinates. The model was fixed and calibrated for automatic drilling. At last, the accuracy was calculated by optic scanning instrument.The installment and preparation cost 10 minutes, the drilling procedure cost 12 minutes. The outside position error was (1.71 ± 0.16) mm, the inside position error was (1.37 ± 0.28) mm, the orientation error was (3.04 ± 1.02)°. Additionally, a total of 5 beagles were tested, with an accuracy error of (2.78 ± 1.52) mm. No postoperative complications occurred.This is the first study reported for robot-assisted automatic surgery in craniofacial surgery. The result shows it is possible to realize the automatic drilling procedure under the condition of no interference like soft tissues. With the development of artificial intelligence and machine vision, robot-assisted surgery may help surgeons to fulfill more automatic procedures for craniofacial surgery.

Postoperative facial swelling after mandibular angle ostectomy is a concern for patients as it affects their quality of life. This study aimed to evaluate the effect of hyperbaric CO2 cryotherapy in relieving postoperative swelling. Thirty-seven patients (mean age: 22.95 ± 3.49 years) who underwent bilateral mandibular angle ostectomy from April to October 2019, were included in this study. A split-mouth design was adopted and through a random sequence, either side of the face was designated as the experimental side. Both received routine nursing care, while the experimental side underwent an additional hyperbaric CO2 cryotherapy treatment. The facial structure was recorded by a 3-dimensional laser scanner pre- and postoperatively. Geomagic Studio was used for alignment, visualization, and quantification of the swelling. The largest deviation value on each side was adopted to assess the overall swelling. Parameters were compared using the paired t-test, and P

Background: The clinical research reports on robot-assisted surgery (RAS) in mandibular contouring surgery are lacking. Our objective was to follow up on the effectiveness and safety of RAS for craniofacial bone surgery over a long period of time. Methods: This small sample early phase prospective randomized controlled study included patients diagnosed with mandibular deformity requiring mandibular contouring surgery. Patients of both genders aged 18-30 years who did not have complicated craniofacial repair defects were enrolled and were randomly assigned in a 1:1 ratio by a permuted-block randomized assignments list that was generated by the study statistician. The control group was treated with traditional mandibular contouring surgery, while the experimental group was treated with robot-assisted mandibular contouring surgery. This was an open trial, but patients and evaluators did not know the grouping of patients. The primary outcomes were the position accuracy and angle accuracy of the osteotomy plane. We conducted third-party measurement and evaluation on the accuracy of outcomes 1 week after surgery. Surgical auxiliary measurement index, patient satisfaction scale, surgical pain scale, perioperative period, and complications at 1 week, 1 month, and 6 months after surgery were also analyzed. Findings: From July 11, 2017 to August 20, 2019, 30 patients, 15 in the RAS group and 15 in the traditional surgery group, were enrolled in the study. One patient was lost to follow-up in the final experiment (controlled group), resulting in a total of 14 patients in the traditional surgery group and 15 in the robot-assisted group, whose data were used for statistical analysis. Among the primary outcomes, there was a significant difference in the position accuracy and angle accuracy between the preoperative design and the actual postoperative osteotomy CT between the traditional surgery group and the robot-assisted group. Among the secondary outcomes, apart from the deviation distance of inferior alveolar nerve to the mandibular cutting plane and bone cutting volume compared with the surgical simulation, there was no significant difference in terms of other surgical auxiliary measurement index, patient satisfaction scale, surgical pain scale, perioperative period, and complications. Interpretation: Compared to traditional surgery, robot-assisted mandibular contouring surgery showed obviously improved precision in bone cutting. What’s more, this technology did not increase the risk of patients. However, this technology needs further clinic trial for effectiveness and safety with more cases according to the findings of this early-phase trial. Trial Registration: The Trial was registered in the Chinese Clinical Trial Registry with the registration number chicTR-Inr17011795. Funding Statement: This work was supported by National Natural Science Foundation of China (No. 61672341，61973211，51911540479); The project of Science and Technology Commission of Shanghai Municipality (No. 17441903800, 18DZ2201900, 19441912300); The project of Science and Technology Commission of Fujian Province (No. 2018H0032); The project Science and Technology Department of Hainan Province (ZDYF2018022); The project of Science and Technology Commission of Quanzhou municipality (No. 2018Z028); The project of SJTU Medical and Engineering Cross Fund (No. YG2017ZD03); the project of Interdisciplinary Program of Shanghai Jiao Tong University (ZH2018QNB31)；and the project of Shanghai Jiao Tong University School of Medicine Two-hundred Talent (No. 20161420). Declaration of Interests: All authors declare no competing interests. Ethics Approval Statement: This study was approved by the Independent Ethics Committee of Shanghai Ninth People’ s Hospital affiliated with the Shanghai Jiao Tong University, School of Medicine. The clinical study was conducted according to the requirements of the ethics committee.

Virtual simulation surgical system is a good way to develop surgical instruments, make surgical plan, and train surgeons. At present, due to the deformation of intraoperative soft tissue after retraction and the lack of effective data collection, the surgical simulation of facial contour surgery can only be conducted according to the preoperative computed tomography data. Due to the difficulty of obtaining real operative spatial data, it is difficult for the virtual surgery trajectory planning process to yield a good effect on surgeon training. In this study, an optical tracking device was used to record the actual posture of surgical instruments, patient position, and incision space in the surgical environment, so as to construct a more accurate actual surgical space. The clinical data obtained in this study can be used for virtual simulation of surgical instrument movement and osteotomy, as well as selection, planning, and teaching purposes of surgical programs.