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.

Objective:To investigate the condylar resorption and influencing factors in post mandibular distraction osteogenesis of the hemifacial microsomia patients.Methods:This retrospective study investigated the clinical data of hemifacial microsomia patients who underwent mandibular distraction osteogenesis in the Department of Maxillofacial Surgery, Plastic Surgery Hospital, Chinese Academy of Medical Sciences from October 2008 to August 2021. Three-dimensional models of pre-operation and pre-distractor extraction were created by the analysis of CT data via ProPlan CMF 3.0. The height and volume of the condyle were measured. Data were analyzed statistically. According to the changes of condylar height and volume pre- and post-operation, the condylar height resorption rate and volume resorption rate could be calculated. The volume resorption rate of the affected side between Type-Ⅱa and Type-Ⅱb hemifacial microsomia patients, hemifacial microsomia patients whether wearing a bite plate, prereproductive and adolescent hemifacial microsomia patients were compared with the Mann-Whitney U test. The Spearman correlation coefficient analysis was used to determine the correlations of the condylar volume resorption rate and condylar height resorption rate in the affected side with measurements of elogation distance, preoperative condylar height, patient age, and distractor remaining time in mandible. P<0.05 indicates that the difference was statistically significant. Results:Forty-seven Type-Ⅱa hemifacial microsomia patients(36 male patients, 11 female patients) were included, patient age ranged from 5 to 20 years and the mean age was (8.49±2.60) years, 36 patients were in the prereproductive age(5-<10 years old), and 11 patients were in the adolescent age(10-20 years old). Forty-six Type-Ⅱb hemifacial microsomia patients(34 male patients, 12 female patients) were included, patient age ranged from 5 to 20 years and the mean age was (8.93±3.43) years. Thirty-six patients were in the prereproductive age(5-<10 years-old), and ten patients were in the adolescent age(10-20 years-old). The follow-up period of Type-Ⅱa hemifacial microsomia patients was (8.49±2.60) months, and the follow-up period of Type-Ⅱb hemifacial microsomia patients was (9.79±2.59) months. Facial asymmetry was improved effectively. Surgical part of the bone had good osteogenesis. Mouth opening and closing, speech, and eating were all normal. The condylar volume resorption rate 34.8%(19.1%, 54.3%) in the affected side of Type-Ⅱa hemifacial microsomia was significantly associated with the elogation distance ( r=0.46, P=0.001), and it had no correlation with the height of the affected condyle ( r=-0.12, P=0.421), age of patients ( r=-0.06, P=0.691), and distractor remaining time in mandible ( r=-0.10, P=0.517). The condylar volume resorption rate 61.0%(11.2%, 95.0%) in the affected side of Type-Ⅱb hemifacial microsomia was significantly associated with the height of the affected condyle ( r=-0.45, P=0.002) and had weak correlation with the elogation distance ( r=0.29, P=0.049), and it had no correlation with age of patients ( r=0.06, P=0.705), and distractor remaining time in mandible ( r=0.21, P=0.157). However, there was no significant difference in terms of the condylar volume resorption rate of the affected side between Type-Ⅱa and Type-Ⅱb hemifacial microsomia ( z=-1.90, P=0.058). Whether the hemifacial microsomia patients wearing a bite plate following mandibular distraction osteogenesis did not affect the condylar volume resorption rate of the affected side ( z=-1.17, P=0.242 in Type-Ⅱa hemifacial microsomia, z=-0.17, P=0.869 in Type-Ⅱb hemifacial microsomia). The condylar volume resorption rate of the affected side had no significant difference between prereproductive and adolescent hemifacial microsomia patients ( z=-0.18, P=0.860 in Type Ⅱa hemifacial microsomia, z=-1.50, P=0.134 in Type-Ⅱb hemifacial microsomia). Conclusion:Condylar resorption of the affected side would happen in post mandibular distraction osteogenesis of the hemifacial microsomia patients, and the condylar resorption rate of the affected side has relationship with the elogation distance and affected preoperative condylar height.

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.

Objective:To investigate the condylar resorption and influencing factors in post mandibular distraction osteogenesis of the hemifacial microsomia patients.Methods:This retrospective study investigated the clinical data of hemifacial microsomia patients who underwent mandibular distraction osteogenesis in the Department of Maxillofacial Surgery, Plastic Surgery Hospital, Chinese Academy of Medical Sciences from October 2008 to August 2021. Three-dimensional models of pre-operation and pre-distractor extraction were created by the analysis of CT data via ProPlan CMF 3.0. The height and volume of the condyle were measured. Data were analyzed statistically. According to the changes of condylar height and volume pre- and post-operation, the condylar height resorption rate and volume resorption rate could be calculated. The volume resorption rate of the affected side between Type-Ⅱa and Type-Ⅱb hemifacial microsomia patients, hemifacial microsomia patients whether wearing a bite plate, prereproductive and adolescent hemifacial microsomia patients were compared with the Mann-Whitney U test. The Spearman correlation coefficient analysis was used to determine the correlations of the condylar volume resorption rate and condylar height resorption rate in the affected side with measurements of elogation distance, preoperative condylar height, patient age, and distractor remaining time in mandible. P<0.05 indicates that the difference was statistically significant. Results:Forty-seven Type-Ⅱa hemifacial microsomia patients(36 male patients, 11 female patients) were included, patient age ranged from 5 to 20 years and the mean age was (8.49±2.60) years, 36 patients were in the prereproductive age(5-<10 years old), and 11 patients were in the adolescent age(10-20 years old). Forty-six Type-Ⅱb hemifacial microsomia patients(34 male patients, 12 female patients) were included, patient age ranged from 5 to 20 years and the mean age was (8.93±3.43) years. Thirty-six patients were in the prereproductive age(5-<10 years-old), and ten patients were in the adolescent age(10-20 years-old). The follow-up period of Type-Ⅱa hemifacial microsomia patients was (8.49±2.60) months, and the follow-up period of Type-Ⅱb hemifacial microsomia patients was (9.79±2.59) months. Facial asymmetry was improved effectively. Surgical part of the bone had good osteogenesis. Mouth opening and closing, speech, and eating were all normal. The condylar volume resorption rate 34.8%(19.1%, 54.3%) in the affected side of Type-Ⅱa hemifacial microsomia was significantly associated with the elogation distance ( r=0.46, P=0.001), and it had no correlation with the height of the affected condyle ( r=-0.12, P=0.421), age of patients ( r=-0.06, P=0.691), and distractor remaining time in mandible ( r=-0.10, P=0.517). The condylar volume resorption rate 61.0%(11.2%, 95.0%) in the affected side of Type-Ⅱb hemifacial microsomia was significantly associated with the height of the affected condyle ( r=-0.45, P=0.002) and had weak correlation with the elogation distance ( r=0.29, P=0.049), and it had no correlation with age of patients ( r=0.06, P=0.705), and distractor remaining time in mandible ( r=0.21, P=0.157). However, there was no significant difference in terms of the condylar volume resorption rate of the affected side between Type-Ⅱa and Type-Ⅱb hemifacial microsomia ( z=-1.90, P=0.058). Whether the hemifacial microsomia patients wearing a bite plate following mandibular distraction osteogenesis did not affect the condylar volume resorption rate of the affected side ( z=-1.17, P=0.242 in Type-Ⅱa hemifacial microsomia, z=-0.17, P=0.869 in Type-Ⅱb hemifacial microsomia). The condylar volume resorption rate of the affected side had no significant difference between prereproductive and adolescent hemifacial microsomia patients ( z=-0.18, P=0.860 in Type Ⅱa hemifacial microsomia, z=-1.50, P=0.134 in Type-Ⅱb hemifacial microsomia). Conclusion:Condylar resorption of the affected side would happen in post mandibular distraction osteogenesis of the hemifacial microsomia patients, and the condylar resorption rate of the affected side has relationship with the elogation distance and affected preoperative condylar height.