The repair of craniofacial bone defects remains a significant challenge in regenerative medicine due to their unique embryonic origin (cranial neural crest cell-derived) and complex anatomical functions. To address the scarcity of autologous bone sources and the tumorigenic risks associated with traditional stem cell therapies, stem cell-derived extracellular vesicles (SC-EVs) offer a highly promising cell-free therapeutic strategy. However, a systematic summary of how to develop efficient EV-based treatments tailored to the specific osteogenic microenvironment of the craniofacial region is still lacking. This review systematically summarizes the current applications of SC-EVs in craniofacial bone tissue engineering. The article first focuses on mechanistic analysis, elucidating how EVs promote the repair of calvarial, alveolar, and jaw bones by delivering bioactive molecules (such as miRNAs and proteins) to activate osteogenic/angiogenic signaling pathways and modulate the inflammatory microenvironment. Finally, this paper reviews engineering modification strategies for SC-EVs, including donor cell pretreatment (hypoxia and inflammatory cytokine stimulation) and SC-EV drug loading/surface modification techniques, and explores the challenges and future prospects of SC-EVs in clinical applications.

PurposeThis study aimed to perform a systematic review of the risk factors associated with secondary alveolar bone grafting (SABG) failure in patients with cleft alveolus.MethodsA comprehensive search was conducted across PubMed, Scopus, Embase, and Web of Science databases from their inception to 24 February 2025, to identify relevant studies. The search keywords included “alveolar cleft” combined with either “survival” or “failure.” Studies that investigated risk factors for the failure of SABG using autologous iliac crest bone were included in this review. Relevant data, including odds ratios, hazard ratios, or comparisons of variables between patients with and without SABG failure, were recorded and analyzed.ResultsA total of nine studies, encompassing 1,855 grafts, were included. The most commonly used definition of SABG failure was Bergland grade 3 or 4. Reported failure rates varied significantly across studies, ranging from 1.0% to 45.1%. The primary risk factors for SABG failure included increased age at SABG (reported in four studies), poor oral hygiene (two studies), and the presence of an erupted lateral or canine tooth (three studies). Additionally, non-Caucasian ethnicity, international adoptee, large cleft size, a history of cleft lip/palate revision or oronasal fistula, nasoalveolar molding, and premaxillary osteotomy were also associated with a higher risk of SABG failure. No significant association was found between SABG failure and sex, alveolar cleft type (bilateral or unilateral), preoperative expansion, or preoperative orthodontics.ConclusionsThe definition of SABG failure varied across studies, with Bergland grade 3 or 4 being the most commonly used criteria. The primary risk factors for SABG failure included increased age, poor oral hygiene, and the presence of an erupted lateral or canine tooth. Surgeons should be aware of these risk factors to optimize surgical strategies and guide patients effectively.

Craniofacial microsomia (CFM) is the second most common congenital craniofacial deformity, presenting diverse clinical manifestations and treatments that may influence oral bacteria dysbiosis (OBD). However, research linking CFM to OBD is limited. Saliva samples were collected from 20 patients with CFM and 24 controls. We compared oral microflora and gene function using 16 S ribosomal RNA sequencing and metagenomics. We also evaluated the correlation between CFM clinical phenotypes and microbiota community structure. Patients with CFM demonstrated greater richness and evenness in their oral microflora. The dominant genera included several pathogenic species, such as Actinomyces, Fusobacterium, and Prevotella. Notably, the severity of CFM correlated positively with the abundance of Neisseria and Porphyromonas. Upregulated pathways were primarily linked to biotin and amino acid metabolism, such as Tryptophan metabolism and Lysine degradation, and further underscored the need for focused oral health interventions in this population. This study is the first to indicate that CFM patients exhibit unique oral bacterial dysbiosis, marked by a higher presence of opportunistic pathogens and increased pathways related to oral and systemic health. These findings highlight the importance of monitoring oral health in patients with CFM.

Background Craniofacial microsomia (CFM), the second most common congenital craniofacial deformity, has manifold clinical manifestations and treatments that may interact with oral bacteria dysbiosis (OBD). However, studies exploring the relationship between CFM and OBD are scanty. Methods Saliva samples of 20 patients with CFM and 24 controls were collected, and oral microflora and gene function annotation were compared using 16S ribosomal RNA and metagenomics. The correlation between clinical phenotypes of CFM and microbiota community structure was also evaluated. Results The oral microflora of CFM patients exhibited higher richness and evenness. The dominant genera in CFM were mainly pathogenic and included Actinomyces, Fusobacterium, and Prevotella. The severity of CFM was significantly positively correlated with the abundance of Neisseria and Porphyromonas. The upregulated pathways were primarily enriched in biotin and amino acid metabolism, including Tryptophan metabolism, which positively correlated with the abundance of Neisseria. Conclusion This study suggests for the first time that patients with CFM exhibit distinct oral bacterial dysbiosis, characterized by an elevated prevalence of opportunistic pathogens and upregulated pathways associated with oral and systemic health. These findings provide evidence for corresponding preventions and therapeutic interventions of CFM.

Background: Microgenia and the accompanying plump cheeks or hamster-like facial contour are all unattractive appearances among the Asian. Genioplasty with autogenous bone grafting is one of the effective ways to improve microgenia, in which a suitable donor area with less additional damage, lower infection rate, and more excellent effect is crucial. Methods: Patients who had undergone genioplasty and autogenous external oblique line grafting (G-EOL) were followed up. The operation-related complications, preoperative, and long-term follow-up 3-dimensional spiral computed tomography (3D-CT) were collected and analyzed. Results: Eight female patients who had received G-EOL and received 1 to 3 years of follow-up were included in this study. There were no short-term or long-term complications. CT data of bone of 8 patients and CT data of soft tissue of 6 patients at the preoperative and long term were compared. Through comparing CT data, the width at the level of the intersection of EOL and mandibular body, and the protrusion of the bony chin had improved significantly; the P values were all <0.001. Through measuring the soft tissue and analyzing the data, the ratio of lower and middle facial width, and the distance from the lower lip to Ricketts’ line were all improved, with the P values 0.042 and 0.001, respectively. Conclusions: For patients with microgenia and hamster-like facial contour, the combination of genioplasty and autogenous external oblique line grafting is innovative and effective in improving both the front and side contour of the lower face simultaneously, with excellent stability, bone healing, and low complication rates.

Background: Chin augmentation (CA) is important treatment modality for microgenia. The use of implantable alloplastic biomaterials in CA grows in popularity, and there is no verifiable documentation of patients’ satisfaction about CA with Medpor (CAWM) exists in the literature, this study examined effectiveness of CAWM by analyzing patient satisfaction. Methods: Patients had undergone CAWM were followed up postoperatively. Occurrence of complications was collected, patients’ satisfactions with chin shape and surgical decision were analyzed using FACE-Q scales, the reliability of operation was studied through analyzing the statistics, and the influences of sex and follow-up time on satisfaction were compared. Results: One hundred ten patients who had undergone CAWM received FACE-Q scales and 64 valid questionnaires were collected. 61 (95.3%) showed high satisfaction with chin shape after CAWM (Cronbach α coefficients were all above 0.8), the median values of satisfaction of chin shape and decision making were 85 (67, 100) and 100 (75,100), respectively. The median chin satisfactions of females and males were 87 (67, 100), 79 (61,100). The median chin satisfactions of patients had surgery before 2 years ago and within 2 years were 81 (67, 100), 87 (64,100), respectively. During the follow-up, among 110, 1 (0.91%) developed graft-related infection and 1 (0.91%) developed an allergic reaction, 1 (0.91%) underwent prosthesis removal because dissatisfaction with chin shape. Conclusions: Chin augmentation with prothesis is a safe and efficacious way to improve microgenia. Medpor is the desired implant material with less infection, displacement and bone absorption, which is worthy of promotion and further study in CA surgery.

The treatment for severe hemifacial microsomia (HFM), especially type III case, is extremely difficult. Mandibular distraction osteogenesis (MDO) was rarely used as the primary choice in the treatment of severe type cases. The authors sought to observe the short-term therapeutic outcomes of patients with severe unilateral HFM who underwent MDO first. A retrospective study of children underwent MDO or later received costochondral graft (CCG) for severe unilateral HFM from 2009 to 2019 was conducted. Cephalometric measurements and clinical variables were analyzed to evaluate the effectiveness of MDO first strategy for severe cases and compare disparity between Pruzansky-Kaban classification type IIb and type III groups. Thirty-six patients (23 males and 13 females) underwent MDO first for severe HFM were included for analysis in the present study. The average age at MDO was 8.33 +/- 2.03 years. At the last follow-up, MDO acquired significant improvement in mandibular height, maxillary cant, chin deviation, lip commissural line tilt, and clinical chin deviation (P < 0.05). Distraction results were stable during the short-term follow-up in terms of the mandibular height ratio and maxillary cant (P > 0.05). MDO is a proper primary method for suitable type IIb and type III HFM cases. MDO can immediately and significantly improve the facial skeleton deficiency, extend the associated soft tissue at the same time, and lay foundation for secondary surgery. MDO can achieve the downgrade of HFM deficiency severity. MDO followed by costochondral graft can get satisfactory esthetic and structural consequence for type III patients.

Study Design. Observational and morphological study with three-dimensional (3D) computed tomography (CT) analysis. Objective. To discover the morphology and configuration deformities of craniovertebral junction (CVJ) and upper cervical spine in children with unilateral hemifacial microsomia (HFM). To determine whether there are specific HFM patients who are at higher risk of certain cervical vertebral anomaly. Summary of Background Data. The evaluation for cervical vertebrae anomaly in HFM children, especially in CVJ region, is underreported. Methods. Eighty-eight unilateral HFM children (64 males, 24 females) with four Pruzansky-Kaban types (I, Ila, Ilb, and III) underwent cranial and cervical CT scanning from skull to C5 in neutral position. The 3D morphology and configuration of the occipital condyle, atlas, and axis, etc. were evaluated on the presence of deformed detailed structures of CVJ region. Results. No C1 deformation was found in type I group. Six (14.3%) type Ila cases, seven (33.3%) type IIb cases, and six (37.5%) type Ill cases had lateral masses asymmetry of C1 (P < 0.05). Five (55.6%) type I cases, 17 (40.5%) type Ila cases, 12 (57.1%) type Ilb cases, and 10 (62.5%) type Ill cases had C2 anomaly (P > 0.05). The incidence rate of C1-C2 instability for four groups were 33.3% (type I), 33.3% (type IIa), 33.3% (type IIb), and 31.3% (type Ill), respectively (P > 0.05). Conclusion. For HFM children, the incidence of C1 deformation increased from type I to type Ill. The probability of C2 anomaly and C1-C2 instability in children with different types of HFM is nearly the same. The craniovertebral junction of every HFM child must be monitored carefully for C1-C2 instability before any surgical procedure to avoid atlantoaxial dislocation and spinal cord injury.

Objective:To investigate the morphological characteristics of skull base in children with hemifacial microsomia (HFM) by three-dimensional reconstruction and measurement of skull base.Methods:Three-dimensional spiral CT data of HFM children with unilateral involvement who had not received any treatment from the First Center of Maxillofacial Plastic Surgery, Plastic Surgery Hospital of the Chinese Academy of Medical Sciences from February 2010 to December 2020 were collected. The patients were divided into four groups according to the Pruzansky-Kaban classification standard: Ⅰ, Ⅱa, Ⅱb and Ⅲ. The three-dimensional reconstruction and measurement of the skull base were performed using Mimics 17.0 software. Linear measurements of the skull base included the distance from tuberculum sellae to optic canal (OT), foramen rotundum (FrT), foramen ovale (FT), internal acoustic meatus (IT), hypoglossal canal (HT), and the distance from anterior clinoid process to the lesser wing of the sphenoid bone (ClS) and the petrous ridge of the temporal bone (ClP). The measurement indexes of skull base angle included anterior cranial angle (ACA), middle cranial angle (MCA), posterior cranial angle (PCA), and petrous ridge angle (PRA). SPSS 26.0 software was used for statistical analysis of the measurement result. Paired t-test was used for comparison within each group, and one-way ANOVA was used for comparison between different types. P<0.05 was statistically significant. Results:A total of 40 children with HFM were collected, with 10 cases in each group. The result of skull base angle measurement showed that the MCA of the healthy side of typeⅠHFM was significantly larger than that of the affected side, and the MCA and PRA of the healthy side of type Ⅲ HFM were larger than those of the affected side ( P<0.05). There was no significant difference in the angle of skull base between the healthy side and the affected side of typeⅡa andⅡb HFM ( P>0.05). In terms of linear distance measurement of skull base, FrT and HT on the healthy side of typeⅠHFM were longer than those on the affected side; FrT, IT, HT and ClP on the healthy side of typeⅡa HFM were significantly longer than those on the affected side; IT, HT and ClP on the healthy side of typeⅡb HFM were longer than those on the affected side; and HT on the healthy side of type Ⅲ HFM was longer than those on the affected side ( P<0.05). The difference between FrT and ClP (affected / healthy) of four types of HFM was statistically significant ( P<0.05). Conclusions:The morphology of HFM is different between the affected side and the healthy side. As for the angle of skull base, MCA was obvious smaller in the affected side than that in the healthy side in the type Ⅰ and type Ⅲ HFM. As for the linear measurement, the distance from the hypoglossal canal to the tuberculum sellae on the affected side is shorter than that on the healthy side in each type HFM, indicating that the growth and development of the cranial base on the affected side is affected in a certain degree.

目的 探讨轮廓美容术后感染的相关因素.方法 回顾性分析2016年11月至2019年11月,中国医学科学院北京协和医学院整形外科医院整形十三科接受轮廓美容533例手术患者,总结分析术后感染发生因素.结果 本组患者术后出现感染13例.其中性别因素,男性占8.7％(4/46)、女性占1.84％(9/487),P<0.05;手术时长<3 h占1.88％(3/159),≥3 h占2.67％(10/374),P>0.05;手术部位因素,单部位手术占1.34％(3/224)、2个部位手术占2.60％(6/231)、3个部位手术占5.13％(4/78),P>0.05.13例确诊感染患者细菌培养结果,铜绿假单胞菌2例(15.38％),金黄色葡萄球菌2例(15.38％),链球菌1例(7.69％),8例未检出;术前预防性使用抗生素种类,头孢西丁钠1.84％(9/489)、克林霉素1.23％(4/32),P<0.05.结论 轮廓美容手术术后感染与患者性别相关,与手术时长、手术部位无关;术前预防性应用头孢西丁效果优于克林霉素;术后10 d内易发生轮廓美容术后感染.

Objective:This study focused on evaluating different parts of the airway in patients with hemifacial microsomia classified by the Pruzansky-Kaban classification system.Methods:Volumetric and morphologic airway parameters of 66 children with hemifacial microsomia were measured on 3D models. Using the Pruzansky-Kaban system, the patient cohort was composed of seven I-type, 14 IIa type, 27 IIb type, and 18 III type patients.Results:The total airway volume was not statistically different among groups. In the 3D oropharynx models, volume and surface area of the oropharynx decreased from the type I group to the type IIb group. However, no statistically significant difference was found for length (P = 0.965) or minimum cross-sectional area (mini-CSA, P = 0.550) of the oropharynx in the type III group compared to the other groups. In the 3D laryngopharynx models, the mean-CSA (P = 0.413) and mini-CSA (P = 0.378) were not statistically different among groups. In contrast, volume (P = 0.014), length (P = 0.005), and surface area (P = 0.032) of the laryngopharynx were reduced from type I to type III. Kruskal-Wallis analysis indicated statistically significant differences of volume (P = 0.004), length (P = 0.017), and surface area (P = 0.010) of the laryngopharynx among groups I, IIa, and IIb. The mean-CSA (P = 0.247) and mini-CSA (P = 0.206) of the laryngopharynx were not correlated with the different clinical types.Conclusion:The mean-CSA varied significantly from type I to IIb at the level of oropharynx. In addition, the volume of the laryngopharynx decreased from type I to type III. However, type III was unique in this study with nonseverely airway measurement results.

The aim of this study was to explore how mandibular distraction osteogenesis influences morphological changes in the oropharynx and laryngopharynx. This was a retrospective study of airway parameter measurements in CFM patients undergoing mandibular distraction osteogenesis treatment. The indication for surgical treatment was the obvious facial asymmetry. Mimics 17.0 (Materialise Inc., Belgium) was used to build 3D models of the oro- and laryngopharynx. The minimum cross-sectional area (CSA), mean CSA, volume, length, and surface area were measured in the 3D models. All data were entered into SPSS v. 23.0 (SPSS Inc. USA), with statistical differences assessed pre- and postoperatively using the Wilcoxon test. Thirty-two patients diagnosed with CFM were included in this study. Five were classified as type IIa, 21 as type IIb, and six as type III, using the Pruzansky-Kaban classification. The average age of the patients was 8.34 years; 14 were females and 18 were males. The average traction time was 35.59 days and the average length of traction was 35.81 mm. The total volume of the airway was significantly increased after MDO (p = 0.001). In the oropharynx and laryngopharynx segments, the mean CSA, minimum CSA, and surface area were statistically significantly different. According to the results, expansion of oropharynx and laryngopharynx were evident after MDO. Mandibular distraction osteogenensis (MDO) can expand the volume of the oropharynx and laryngopharynx. Therefore, MDO can be considered a clinically useful treatment for changing the structure of the oropharynx and laryngopharynx.

目的 探讨半侧颜面短小畸形(hemifacialmicrosomia,HFM)患者双侧咬肌方向及机械效益的差异.方法 自2010—2019年,中国医学科学院北京协和医学院整形外科医院颌面整形中心收集23例未经治疗且单侧受累患者的CT数据,输入MIMICs 17.0软件进行三维重建,测量咬肌在矢状面和冠状面的方向角α和β,并计算其机械效益,采用配对t检验比较患侧与健侧的差异.结果 HFM PruzanskyⅡb型患者患侧咬肌倾斜角α小于健侧(P<0.05),HFMⅠ型和Ⅱa型患者患侧咬肌机械效益小于健侧(P<0.01).结论 HFMⅡb患者患侧咬肌在矢状面上相对健侧更加前倾,HFM双侧咬肌机械效益的差异可能与咬(牙合)力的不对称有关.

In hemifacial microsomia (HFM), the aberrant mandible structure has always been the focus of attention. How the maxillary development being affected is not clear. The authors sought to comprehensively evaluate the hemifacial maxillary deficiency and to assess for Pruzansky-Kaban score correlation.This is a retrospective research of children with HFM. Demographic information were recorded, and computed tomographic scan were reconstructed and analyzed by segmentation, volumetric and cephalometric measurements. Analyses involved paired t-test, independent sample t-test and one-way analyses of variance.Demographic information revealed 67 patients diagnosed with HFM were included: 10.4 percent type I, 38.8 percent IIa, 28.4 percent type IIb, 22.4 percent type III. The maxillary total volume was found to be significantly decreased on the affected side in patients with type IIa (P=0.0426) and IIb (P=0.0004). No notable differences in maxillary sinus volume were found. No significant differences in maxillary width measurements were found between groups type I and III. A descending trend in maxillary bone volume ratio, an increasing trend in maxillary posterior width ratio and a decreasing trend in maxillary middle height ratio was observed from group I to IIb (pmbv=0.020; pmpw=0.002; pmmh=0.004).This study comprehensively characterized the hemifacial microsomia maxillary deficiency. For maxillary total volume and transverse development, the type III group presented characteristics similar to the type I group. We concluded that the severity of maxillary deficiency is not completely consistent with the mandibular deformity classification.

In hemifacial microsomia (HFM), the correlations between mandibular dysplasia and maxillary deformities in HFM patients have not yet been assessed. The objective of the present study was to examine the association of maxillary volumetric and linear measurements with mandibular ramus height or corpus length on the affected side in children with unilateral HFM.In this retrospective research, a total of 70 children with unilateral HFM were enrolled at our department from 2010 to 2019. Demographic information was recorded, and computed tomographic scan were reconstructed and analyzed by segmentation, volumetric, and cephalometric measurements. Analyses involved independent sample t-test, univariable, and multivariable linear regression.In the overall population, mandibular ramus height (MRH) was positively associated with the maxillary bone volume (MBV) (r = 0.484, P < 0.001) and maxillary total volume (MTV) (r = 0.520, P < 0.001). Similarly, mandibular corpus length (MCL) was significantly associated with the MBV (r = 0.467, P < 0.001) and MTV (r = 0.520, P < 0.001). Multivariate regression analysis revealed that the MRH or MCL were significantly and independently associated with MBV or MTV (MRH/MBV β = 0.420, P < 0.001; MRH/MTV β = 0.391, P < 0.001; MCL/MBV β = 0.403, P < 0.001; MCL/MTV β = 0.307, P < 0.01).These results demonstrated that the MBV and MTV are independently associated with MRH or MCL on the affected side in children with unilateral HFM, suggesting a potential interaction between mandibular dysplasia and maxillary deformities.

目的 探讨建立一套针对半侧颜面短小畸形(hemifacial microsomia,HFM)上颌骨形态准确的三维测量方法,并在此基础上分析HFM上颌骨发育不良的特点.方法 收集60例未经治疗且单侧受累的HFM儿童的头颅螺旋CT三维数据,并应用Mimics软件对数据进行三维重建和测量.使用组内相关系数、配对t检验和线性回归进行统计分析.结果 各测量值均具有良好的可靠性(ICC＞0.73);Ⅲ型HFM患侧与对侧的上颌骨后部及牙弓宽度的差异无统计学意义(P＞0.05).从Ⅰ型到Ⅱb型,上颌骨后部宽度比率逐渐增加,后部高度比率逐渐降低(P＜0.05).结论 应用螺旋CT和软件评估HFM上颌骨形态的方法,为明确不同分型的HFM上颌骨畸形特点建立了可靠的方法基础.Ⅲ型HFM上颌骨的横向发育未受到显著影响,从Ⅰ型到Ⅱb型上颌骨畸形严重程度逐渐加重.

Objective To present the overall therapy to correct mandible deformities and modify facial contour of patients who have been diagnosed as auriculo—condylar syndrome (ACS) in our hospital.Methods We formulate effective therapeutic plan for every single patient based on digital surgical techniques.Three patient received individualized therapy,which include bilateral Distraction osteogenesis,orthodontic treatment,genioplasty,LeFort Ⅰ osteotomy,Chin augmentation with porous polyethylene implant,or mandibular contour correction with porous polyethylene implant.Results All three patients gained satisfactory surgical resuhs.Occlusal function and sleeping quality in 2 severe patients was significantly improved.Conclusions Clinical features of ACS is complex,which may range from mild to severe in different patients.Individualized therapeutic plan of comprehensive treatment should be established after facial deformity evaluation and surgical simulation based on surgical techniques.

目的 探讨半侧颜面短小畸形患儿与同龄正常儿童口腔(牙合)力大小及分布的差异.方法 随机选取自2014年5月至2018年2月在中国医学科学院整形外科医院咨询、就诊的6～10岁半侧颜面短小畸形(hemifacial microsomia,HFM)患儿及颌骨发育正常儿童共74例进行(牙合)力测量,分为HFM组和正常组.采用第一磨牙/乳磨牙区测量值作为最大(牙合)力,左右两侧各测3次,分别记录左、右侧最高的数值.同时记录受试者的年龄、性别、咀嚼习惯以及半侧颜面短小畸形患儿的Pruzansky-Kaban分型.综合以上数据,将HFM患儿与同龄正常儿童的测量值相比较,进行统计学分析.结果 HFM组健侧平均最大(牙合)力为(238.28±61.87)N,与正常同龄儿童平均最大(牙合)力(256.22±53.58)N相比,差异无统计学意义(P＞0.05).HFM组患侧平均最大(牙合)力为(162.14±30.46)N,与正常同龄儿童平均最大(牙合)力比较,其差异具有统计学意义(P＜0.05).在HFM患儿中,同一患者的左右侧(牙合)力分布不平衡,差异具有统计学意义(P＜0.05).结论 HFM患儿存在不同程度的(牙合)力分布不均的特点,较同龄正常儿童而言,其患侧(牙合)力减弱,健侧基本可代偿.

Background: The relapse of hemifacial microsomia was thought to be highly related to the soft tissue envelope around the mandible angle mainly composed by masseter and medial pterygoid. According to the reason, we tried to apply masseter injection of type A botulinum toxin to weaken the soft envelope tension on the early stage post mandible distraction in adult HFM patients. Methods: Eight patients diagnosed with HFM were studied and randomly assigned to an experimental or control group. Patients in the experimental group were treated with DO, orthognathic surgeries, autologous fat grafting, and bilateral masseter muscle injection with type A botulinum toxin. The patients in control group were treated with the same procedures as the patients in experimental group except for masseter muscle injection with type A botulinum toxin. The recurrence rates of both groups were evaluated and analyzed after nearly 1 year of follow-up. Results: The mean recurrence rate was 26.30% +/- 11.84% ( range 7.62%-37.27%) in the 8 patients after 1-year follow-up. The relapse rate was 16.32% +/- 7.78% (7.62%-26.22%) in the experimental group and 36.28% +/- 1.03% (34.84%-37.27%) in the control group. There was a significant difference (P = 0.002) between the experimental group and the control group. Conclusions: The combination of DO, orthognathic surgeries, autologous fat particle transplantation, and masseter muscle type A botulinum toxin injection technique could be a comprehensive treatment plan for adult patients of HFM. Furthermore, masseter injection of type A botulinum toxin might be an alternative method to reduce the early recurrence rate of postoperative adult patients of HFM.

Objective To investigate the influence of mandibular distraction osteogenesis on masticatory function by analyzing the maximal bite force before and after surgery. Methods From May 2014 to November 2015, 22 hemifacial microsomia cases, ageing from 6 to 10 years old, underwent mandibular distraction osteogenesis and their biting force data were collected. The maximal bite forces in incisor area, bilateral premolar area and molar area were measured before surgery and 1 year after surgery. Results The average maximum bite forces in the molar area of the affected side, premolar area of the affected side, incisor area, premolar area of the unaffected side, molar area of the unaffected side were (170. 6 ± 42. 8) N, (141. 9 ± 34. 9) N, (89. 7 ± 18. 8) N, (169. 3 ± 29. 0) N and (230. 2 ± 56. 4) N respectively before surgery. Statistics indicated that most patients had uneven distribution of bite force between the affected side and unaffected side before surgery. And they changed to ( 198. 8 ± 44. 0 ) N, (151. 8 ±31. 1)N, (88. 9 ±18. 0) N, (167. 8 ±26. 1)N and (234. 3 ±52. 5)N respectively 1 year after surgery, showing that the bite force in the molar area of the affected side was significantly improved by the surgery(P<0. 05). Regression analysis showed that the postoperative bite force distribution had a tendency to become more symmetrical in hemifacial microsomia patients. Conclusions Mandibular distraction osteogenesis can improve the bite force of the affected side in hemifacial microsomia patients and enhance the balance of masticatory in the long-term postoperatively.