Three-Dimensional Anthropometric Facial Analysis and Fitting Discrepancies Between Stereophotogrammetry and CT.

BACKGROUND: The reliability and repeatability of stereophotogrammetry and CT in 3-dimensional anthropometric facial analysis were investigated in this study, which also explored the clinical application of supine CT. METHOD: In this study, 3D CT and 3dMD stereophotogrammetry were used on 20 healthy volunteers. The fitting distance between stereophotogrammetry and CT scans at landmark points was measured, along with facial feature measurements (Al-Al) face width (Go-Go, Zy-Zy, Ex-Ex), and hemi-face height (Sn-Gn). The intraclass correlation coefficient (ICC) was employed to assess interrater agreement and to verify the reliability of the measurement methods. Paired t -analysis was utilized for analyzing intramethod displacement. RESULTS: The alare, nasion, and pronasale points were found to be minimally influenced by different positions and are more recommended as landmark points for registration. CT demonstrated good interrater reliability on all indicators. In stereophotogrammetry, measurements for Go-Go and Zy-Zy displayed an interclass correlation coefficient (ICC) of less than 0.75. Significant differences between the 2 methods were observed for En-En, Ex-Ex, and Go-Go ( P < 0.05). Specifically, CT analysis for Go-Go showed a measurement 2.34 mm larger than that obtained with the 3dMD method. CONCLUSION: Both CT and stereophotogrammetry were found to be reliable methods for evaluating facial soft tissue. It is speculated that Go-Go measurement is primarily influenced by factors such as different positions, facial expressions, and gravity. These variables should be carefully considered during the evaluation of the mandibular angle region.

Discrepancy in Mandibular Medullary Cavity on Different Sides: More Hints Towards Understanding Hemifacial Microsomia.

The authors attempt to approach hemifacial microsomia with macroscopic techniques and look for a link between clinical manifestations with pathogenesis. In this study, for the first time mandibular medullary cavities as essential parts of the mandible were intravitally measured based on the 3-dimensional models. A total of 153 patients were included. The 3-dimensional models of patients' mandibles were reconstructed and medullary cavity volumes (mm 3 ) were measured. The ratio of medullary cavity volume to mandible volume was calculated to determine the proportion of the marrow in the bone. Statistical significance was found in mandible volumes ( P <0.001) and medullary cavity volumes ( P <0.001) on different sides. Medullary cavity volumes were significantly related to mandible volumes on both sides (both P <0.001). Medullary cavity volumes on the nonaffected and affected side were both in correlation with age but in different degrees ( r =0.214, P =0.008 versus r =0.170, P =0.036). The ratios of medullary cavity volume and the mandible were significantly different ( P <0.001) on 2 sides. The volume ratio on the nonaffected side correlated to age while this correlation did not exist on the affected side ( r =0.195, P =0.016 versus r =0.129, P =0.112). A smaller medullary cavity found on the affected side could lead to a reduced amount of bone marrow cells and consequently reduced osteogenic and hematopoietic potential. This could result in abnormal bone formation on the affected side of mandible. Proportions of marrow in bone on the affected side irrelevant to patients' ages signify a poorer potential of expansion. This may explain a higher reluctancy of growth in affected mandibular sides.

Feasibility of a Robot-Assisted Surgical Navigation System for Mandibular Distraction Osteogenesis in Hemifacial Microsomia: A Model Experiment.

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, P <0.001) 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.

Three-dimensional Printing Technologies in Craniofacial Plastic Surgery: An Institutional Experience.

Rapid developments in 3-dimensional(3D) printing technologies in craniofacial plastic surgery have provided a new treatment modality for patients. In this article, we intend to share our institution's experience using 3D printing in 3 modes-namely, 3-dimensional printing for manufacturing contour models, guides, and implants. Fifty-nine patients were enrolled in our study between September 2009 and September 2021. Among the 3D printing-assisted technologies, 41 cases were used for congenital malformations, 82 for trauma repair, and 112 for cosmetic surgery. Preoperative design and postoperative data were compared and analyzed based on imaging data. In craniofacial plastic surgery, all patients had excellent postoperative objective bone measurements close to the preoperative design and improved esthetic appearance. Our survey of postoperative satisfaction showed that patients were quite satisfied with the surgery, especially concerning congenital deformities. Rapid prototyping 3-dimensional printing technology provides a practical and anatomically accurate means to produce patient-specific and disease-specific translational tools. These models can be used for surgical planning, simulation, and clinical evaluation. Expanding this technology in craniofacial plastic surgery will provide adequate assistance to practitioners and patients.

Radiomics and Artificial Intelligence Study of Masseter Muscle Segmentation in Patients With Hemifacial Microsomia.

BACKGROUND: Hemifacial microsomia (HFM) is one of the most common congenital craniofacial condition often accompanied by masseter muscle involvement. U-Net neural convolution network for masseter segmentation is expected to achieve an efficient evaluation of masseter muscle. METHODS: A database was established with 108 patients with HFM from June 2012 to June 2019 in our center. Demographic data, OMENS classification, and 1-mm layer thick 3-dimensional computed tomography were included. Two radiologists manually segmented masseter muscles in a consensus reading as the ground truth. A test set of 20 cases was duplicated into 2 groups: an experimental group with the intelligent algorithm and a control group with manual segmentation. The U-net follows the design of 3D RoI-Aware U-Net with overlapping window strategy and references to our previous study of masseter segmentation in a healthy population system. Sorensen dice-similarity coefficient (DSC) muscle volume, average surface distance, recall, and time were used to validate compared with the ground truth. RESULTS: The mean DSC value of 0.794±0.028 for the experiment group was compared with the manual segmentation (0.885±0.118) with α=0.05 and a noninferiority margin of 15%. In addition, higher DSC was reported in patients with milder mandible deformity ( r =0.824, P <0.05). Moreover, intelligent automatic segmentation takes only 6.4 seconds showing great efficiency. CONCLUSIONS: We first proposed a U-net neural convolutional network and achieved automatic segmentation of masseter muscles in patients with HFM. It is a great attempt at intelligent diagnosis and evaluation of craniofacial diseases.

Preliminary Application Research of 3D Bioprinting in Craniofacial Reconstruction.

INTRODUCTION: In recent years, 3-dimensional (3D) printing has been widely used in regenerative medicine research and other fields because of its ability to customize macroscopic morphology and precisely control microstructure. Polymer scaffolds are 1 of the commonly used 3D bioprinting materials for defect repair and have recently been a research focus. Our article explored the bone-formation accelerating effect of 3D-printed porous scaffold Poly(glycerol sebacate) [PGS] in the critical bone defect of an enhancing rabbit mandibular model. Also, we overview and summarize the classification of 3D bioprinting materials and prospects for their various application scenarios in craniofacial reconstruction surgery. MATERIALS AND METHODS: A PGS elastomer scaffold was prepared by polymerizing equimolar amounts of sebacic acid and glycerol using a biological 3D printer. Six male New Zealand white rabbits were prepared (3 for the control group and 3 for the PGS group), each weighing 3 kg. Osteotomy was performed at the anterior edge of the ascending ramus of the mandible with a bone saw to open the 8 mm defect. Defects of the control group were empty, and defects of the PGS group were put into 8 mm-wide PGS elastomer scaffolds. The rabbits were euthanized 6 weeks after the operation, and the postoperative mandibles were collected. Information (presence or absence of pus from infection, nonunion, degree of macroscopic bone healing) was recorded, and the skeletal tissue was fixed in a paraformaldehyde solution. RESULTS: The mandible on the enhanced side was significantly longer than that on the opposite side, and the contralateral incisor was hyperplasia. The mandibles of rabbits in each group healed well, and there was no obvious local infection and purulence. The gross specimen appearance showed that both ends of the defect were connected. When comparing the reconstructed mandibles of the two groups, it is apparent that the width and thickness of the new bone in the PGS group were significantly better than that in the control group. CONCLUSIONS: This article verifies the effect of 3D polypore PGS scaffolds in animal craniomaxillofacial bone defects and introduces various application scenarios of 3D printing materials in craniomaxillofacial reconstruction surgery. There are quite good application prospects for 3D bioprinting in animal experiments and even clinical treatment of craniofacial defects.

Changes in Facial Soft Tissues After Mandibular Angle Ostectomy Based on 3-Dimensional Measurement: A Clinical Study.

PURPOSE: A limited number of clinical studies have focused on the changing trends of facial soft tissue after mandibular angle ostectomy. We conducted this study to investigate the changes in facial muscles and facial soft tissue appearance before and after mandibular angle ostectomy. MATERIAL AND METHODS: A single-center retrospective cohort study was conducted on female patients admitted to our hospital for mandibular angle ostectomy between 2019 and 2020. The primary predictor variable was time (preoperative vs 6 months postoperative). The primary outcome variables were surface area and total volume of the manually delineated region of interest (ROI) for the masseter and temporalis muscles. We utilized computed tomography data to reconstruct 3-dimensional models to delineate muscle ROI and then measure them computationally. Secondary outcome variables were indicators of mandible appearance in soft tissue including bilateral mandibular angle distance, mandibular ramus height, and mandibular angle value. Age, preoperative body mass index, and ostectomy volume were chosen as covariates for correlation analysis with outcome variables. Paired t tests and Pearson correlation analysis were conducted, and P values < .05 were considered statistically significant. RESULTS: A total of 29 female patients (mean age, 26 years; range, 18 to 37 years) who underwent mandibular angle ostectomy in our hospital were included. The surface area and total volume of the masseter muscle ROI were reduced by 2,541.2 ± 1,925.0 mm2 (12.8%; P < .05) and 16,242.4 ± 12,646.8 mm3 (18.4%; P < .05), respectively, 6 months after surgery. In contrast, the surface area and total volume of the temporalis muscle ROI increased by 6,081.6 ± 6,169.4 mm2 (12.0%; P < .05) and 19,273.3 ± 21,666.2 mm3 (10.7%; P < .05), respectively. The ostectomy volume showed a correlation coefficient of 0.59 with postoperative masseter ROI change (P < .05). CONCLUSION: We observed statistically significant levels of atrophy of the masseter muscle ROI and expansion of the temporalis muscle ROI 6 months after mandibular angle ostectomy, which may account for appearance changes after surgery. Besides, ostectomy volume positively correlates with postoperative masseter ROI changes. In summary, our study provided empirical evidence illustrating soft tissue alterations in patients who have undergone mandibular angle ostectomy.

Correlations Between Mandible Condylar Structures and External Ear Deformities in Hemifacial Microsomia With Three-Dimensional Analysis.

ABSTRACT: 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 of age). 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   <  0.001). Either between the condyle and external ear ( P  = 0.071-0.493) or between the condylar unit and external ear ( P  = 0.080 - 0.488), there were no volumetric relations on the affected side, whereas on the unaffected side were (r = 0.492-0.929 for condyle, r = 0.443-0.929 for the condylar unit, P  < 0.05). In most cases, the condylar structures of the classification of the mandibular or ear deformities (M2b) were significantly smaller than the classification of the mandibular or ear deformities (M2a). Results suggested deformities of mandibular condylar structures and ear did not correlate, although deformities of mandible and ear did. The condylar deformity might develop independently from microtia and be more severe within relatively more abnormal temporomandibular joints.

OMENS+ Classification Correlations Analysis of Craniofacial Microsomia in China: The Relationship Between Macrostomia and Mandibular Hypoplasia.

ABSTRACT: 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.

Correcting facial asymmetry through guided plate assisted mandibular angle osteotomy.

Background: Asian women prefer a smooth and narrowed mandibular appearance. The purpose of the retrospective cohort study is to evaluate guide plate-assisted mandibular angle ostectomy (MAO) in improving mandibular symmetry for Asian female patients with mandibular angle hypertrophy (MAH) with normal occlusal relationship. Methods: We retrospectively examined 11 patients with asymmetry MAH with normal occlusal relationship who received MAO at Shanghai Ninth People's Hospital between September, 2020, and January, 2022. Preoperative plans were designed based on CT data and executed using metal guide plate during the operation. Preoperative and one-week postoperative CT scans were used to assess measurements including Height_Go, Divergence_Go, ∠ZyZy-GoGo, and osteotomy volume, to evaluate symmetry. For precision, compare the postoperative CT with the preoperative design, assessing osteotomy distance, angle, and volume error. Patient satisfacation was evaluated with Likert Scale in 6-month follow-up. Secondary lipofilling procedures were given as appropriate. Statistical analysis was performed using paired t-tests in SPSS. Results: The mean age of the 11 patients was 28.5 years (range 23-34 years). 2 of these underwent lipofilling procedures. No complications were observed during the following-up. Postoperative results were not statistically different from the design, demonstrating a precision of within 2 mm. Height_Go disparity within 5 mm get corrected notably, reducing asymmetry from 15.09% preoperatively to 2.74% postoperatively. Patients satisfaction was rated at 4.5 out of 5 in 6 month follow-up. Conclusions: Guide plate-assisted mandibular angle osteotomies achieve effective and precise surgery. This approach demonstrates a safe option for correction for mandibular asymmetry, achieving patient satisfaction.

Changes of masseter muscle after mandible distraction osteogenesis in patients with Hemifacial microsomia: a retrospective study.

Introduction: Mandible distraction osteogenesis (MDO) is widely used to reconstruct the mandible in patients with mild Hemifacial microsomia (HFM). However, the masseter's response to mandible distraction remains unclear. Methods: In this study, we analyze the effect of the surgical intervention on masseter muscle by a retrospective analysis. The procedure consisted of a five-day latent period, a three-week distraction period, and a six-month consolidation period. CT data were manually segmented and measured with Mimics software before surgery, within 3 months, and more than 1 year postoperatively. Masseter volume, masseter length, masseter width, and mandible ramus height were measured and analyzed using paired t-test, Pearson, and Spearman correlation analysis. Results: We included 21 patients with HFM who underwent mandible distraction osteogenesis from 2015 to 2020. The masseter volume on the affected side increased immediately after surgery from (6,505.33 ± 3,671.95) mm3 to (10,194.60 ± 5638.79) mm3, but decreased to (8,148.38 ± 3,472.57) mm3 at the second follow-up correlated to mandible ramus height (r = 0.395, P = 0.038). A similar trend was observed in changes in masseter length. Symmetry and width of masseter muscle had no longitudinal statistical significance. Discussion: Masseter muscle involvement benefits from MDO in the short term. To achieve long-term efficacy, more attention should be paid to muscle reconstruction.

Morphological and quantitative study of the inferior alveolar nerve canal in hemifacial microsomia.

This study aimed to probe into the anatomic course of inferior alveolar nerve canal (IANC) in hemifacial microsomia (HFM) on a large scale, morphological observations and further quantitative study were performed. Patients were classified by Pruzansky-Kaban classification. The anatomic course of IANC was analyzed morphologically with three-dimensional (3D) imaging software among 248 patients. Seven distances between fixed landmarks on both sides were measured for 236 patients. The differences between affected and unaffected sides were compared. Significant differences were found in the entrance (P < 0.001), route (P < 0.001), and exit (P < 0.05) of IANC in type IIb and III HFM. The higher the degree of mandibular deformity was, the higher the incidence of IANC variation was (P < 0.05). The distances in the horizontal aspect of IANC including from mandibular foramen to mental foramen (P < 0.05) and from mental foramen to gonion (P < 0.05) were significantly shorter on the affected side. Abnormalities of the anatomical course of IANC exist in patients with Pruzansky-Kaban type IIb and type III HFM. The reduction of IANC on the affected side in the horizontal distance is more obvious. Three-dimensional imaging assessment is recommended before surgery.

Efficacy of navigation system-assisted distraction osteogenesis for hemifacial microsomia based on artificial intelligence for 3 to 18 years old: study protocol for a randomized controlled single-blind trial.

BACKGROUND: Mandibular distraction osteogenesis (MDO) is a major part of the treatment for hemifacial microsomia patients. Due to the narrow surgical field of the intraoral approach, osteotomy accuracy is highly dependent on the surgeons' experience. Electromagnetic (EM) tracking systems can achieve satisfying accuracy to provide helpful real-time surgical navigation. Our research team developed an EM navigation system based on artificial intelligence, which has been justified in improving the accuracy of osteotomy in the MDO in animal experiments. This study aims to clarify the effect of the EM navigation system in improving the MDO accuracy for hemifacial microsomia patients. METHODS: This study is designed as a single-centered and randomized controlled trial. Altogether, 22 hemifacial microsomia patients are randomly assigned to the experiment and control groups. All patients receive three-dimensional CT scans and preoperative surgical plans. The EM navigation system will be set up for those in the experiment group, and the control group will undergo traditional surgery. The primary outcome is the surgical precision by comparing the osteotomy position of pre- and postoperative CT scan images through the Geomagic Control software. The secondary outcomes include mandibular symmetry (occlusal plane deviation angle, mandibular ramus height, and body length), pain scale, and complications. Other indications, such as the adverse events of the system and the satisfactory score from patients and their families, will be recorded. DISCUSSION: This small sample randomized controlled trial intends to explore the application of an EM navigation system in MDO for patients, which has been adopted in other surgeries such as orthognathic procedures. Because of the delicate structures of children and the narrow surgical view, accurate osteotomy and protection of nearby tissue from injury are essential for successful treatment. The EM navigation system based on artificial intelligence adopted in this trial is hypothesized to provide precise real-time navigation for surgeons and optimally improve patient outcomes, including function and aesthetic results. The results of this trial will extend the application of new navigation technology in pediatric plastic surgery. TRIAL REGISTRATION: Chinese Clinical Trial Registry ChiCTR2200061565. Registered on 29 June 2022.

Piezosurgery in hemifacial microsomia: a promising exemption from conventional peri-osteotomy suffering.

Introduction: Mandibular distraction osteogenesis, a recommended therapy for hemifacial microsomia, has brought much agony because of its traumatic procedures and peri-osteotomy complications. Our study aims to retrospectively compare piezoelectric osteotome with conventional reciprocal bone saw for hemifacial microsomia patients and validate its meliority in operability, surgical risks and patient outcomes. Methods: All patients included underwent osteotomies conducted by either piezosurgery or bone saw. Information of intraoperative blood loss, operation duration, postoperative pain and complications was collected from patient files, ward round inspections and follow-ups. Results: Among all 40 patients, 13 underwent piezo-osteotomy. Piezosurgery performed better than conventional reciprocal bone saw in decreasing intraoperative blood loss (p < 0.001) and operation duration (p = 0.030). No significant difference was found in hospitalization duration, total expenses or complication rates between two groups. There were positive relations between operation duration and intraoperative blood loss (p = 0.042), and between hospitalization duration and total expenses (p = 0.0096). Postoperative pain scores of both groups declined over time while the piezosurgery group had a statistically significant tendency (p = 0.006) to suffer less than the conventional group. Discussion: Piezosurgery diminishes intraoperative blood loss, operative duration, and postoperative pain, making an alternative to conventional osteotomes to mitigate patients' and families' peri-osteotomy sufferings, and a more humane solution to HFM.

Applying artificial intelligence algorithm in the design of a guide plate for mandibular angle ostectomy.

PURPOSE: Surgical guide plates can improve the accuracy of surgery, although their design process is complex and time-consuming. This study aimed to use artificial intelligence (AI) to design standardized mandibular angle ostectomy guide plates and reduce clinician workload. METHODS: An intelligence algorithm was designed and trained to design guide plates, with a safety-ensuring penalty factor added. A single-center retrospective cohort study was conducted to test the algorithm among patients who had visited our hospital between 2020 and 2021 for mandibular angle ostectomy. We included patients diagnosed with mandibular angle hypertrophy and excluded those combined with other facial malformations. The guide plate design method acted as the primary predictor, which was AI algorithm vs. experienced residents. Moreover, the symmetry of plate-guided ostectomy was chosen as the primary outcome. The safety, shape, location, effectiveness, and design duration of the guide plate were also recorded. The independent samples t-test and Pearson's chi-squared test were used and P-values < 0.05 were considered significant. RESULTS: Fifty patients (7 men, 43 women; 27 ± 4 years) were included. The two groups differed significantly in terms of safety (7.02 vs. 5.25, P < 0.05) and design duration (24.98 vs. 1685.08, P ＜ 0.05). The ostectomy symmetry and shape, location, and effectiveness of the guide plates did not differ significantly between the two groups. CONCLUSIONS: The intelligent algorithm can improve safety and save time for guide plate design, ensuring other quality of the guide plates. It has good potential applicability in accurate mandibular angle ostectomy.

Quantitative structural analysis of hemifacial microsomia mandibles in different age groups.

Introduction: This study aims to quantitively analyze mandibular ramus and body deformities, assessing the asymmetry and progression in different components. Methods: This is a retrospective study on hemifacial microsomia children. They were divided into mild/severe groups by Pruzansky-Kaban classification and into three age groups (<1 year,1-5 years, 6-12 years old). Linear and volumetric measurements of the ramus and the body were collected via their preoperative imaging data to compare between the different sides and severities, using independent and paired tests, respectively. The progression of asymmetry was assessed by changes in affected/contralateral ratios with age using multi-group comparisons. Results: Two hundred and ten unilateral cases were studied. Generally, the affected ramus and body were significantly smaller than those on the contralateral side. Linear measurements on the affected side were shorter in the severe group. Regarding affected/contralateral ratios, the body was less affected than the ramus. Progressively decreased affected/contralateral ratios of body length, dentate segment volume, and hemimandible volume were found. Discussion: There were asymmetries in mandibular ramus and body regions, which involved the ramus more. A significant contribution to progressive asymmetry from the body suggests treatment focus in this region.

Preliminary study of the accuracy and safety of robot-assisted mandibular distraction osteogenesis with electromagnetic navigation in hemifacial microsomia using rabbit models.

This study aimed to investigate the accuracy and safety of mandibular osteotomy and distraction device positioning in distraction osteogenesis assisted by an electromagnetic navigation surgical robot. Twelve New Zealand white rabbits were randomly divided into two groups after computed tomography. The control group underwent a procedure based on the preoperative three-dimensional design and clinical experience. Animals in experimental group underwent a procedure with robotic assistance after registration. The accuracies of osteotomy and distraction device positioning were analysed based on distance and angular errors. The change in ramus length after a 1 cm-extension of the distraction device was for assessing distraction effect. The preparation, operative and osteotomy times, intraoperative bleeding, and teeth injury were used for safety assessment. In the experimental group, the distance (t = 2.591, p = 0.011) and angular (t = 4.276, p = 0.002) errors of osteotomy plane, and the errors in distraction device position (t = 3.222, p = 0.009) and direction (t = 4.697, p = 0.001) were lower; the distraction effect was better (t = 4.096, p = 0.002). There was no significant difference in the osteotomy time and bleeding; however, the overall operative and preparation times were increased in the experimental group, with a reduced rate of teeth damage. Robot-assisted mandibular distraction osteogenesis with electromagnetic navigation in craniofacial microsomia is feasible, safe, significantly improves surgical precision.