Three-Dimensional Measurement of the Temporomandibular Joint in Pruzansky-Kaban Type IIa Hemifacial Microsomia.

OBJECTIVE: This observational retrospective cross-sectional study aimed to investigate the morphological characteristics of the temporomandibular joint (TMJ) in type IIa hemifacial microsomia (HFM). METHODS: We recruited 88 patients with unilateral type IIa HFM. Data relating to the length, distance, and angle of the TMJ, were measured on 3-dimensional models created by the analysis of computed tomography data. Normality analysis was performed by using the Shapiro-Wilk test. Data were compared with the paired t test and Wilcoxon signed-rank test. RESULTS: The height, long axis, and short axis of the affected condyle were significantly shorter than the unaffected side ( P <0.001); the ratios were 0.41±0.15, 0.75±0.20, and 0.95±0.24, respectively. The spaces between the condyle and the glenoid fossa were significantly larger in affected TMJs ( P <0.001). The ratio between the ipsilateral and contralateral anterior space in the sagittal plane was 4.62±2.59; this was significantly different than the ratio of inner space (1.50±1.70), superior space (1.70±0.97), and lateral space (1.28±0.62) in the coronal plane ( P <0.001) and the ratio of superior space (1.43±1.05) and posterior space (1.47±0.98) in the sagittal plane ( P <0.001); there were no statistical differences between the 5 spaces ( P >0.05). The breadth and depth of the glenoid fossa were significantly shorter in affected TMJs ( P <0.001), the ratio of the breadth in the affected and unaffected glenoid fossa was between 0.5 and 1 and the depth of the affected glenoid fossa was almost half of that on the unaffected side. The ratio between the ipsilateral and contralateral height of the condyle was significantly different when compared with the length of the mandibular ramus ( P <0.001). The ratio between the ipsilateral height of the condyle and the length of the mandibular ramus was significantly different when compared with that of the contralateral side ( P <0.001). The height of the affected condyle were significantly different ( P =0.005) among different ages. CONCLUSIONS: We found that hypoplasia was more severe in terms of the height of the condyle than the long axis and short axis of the condyle. The degree of condyle deformity was more severe than the mandible. And the affected condyle still had growth potential in the vertical direction with age.

Morphologic Changes of the Temporomandibular Joint in Pruzansky-Kaban Type IIa Hemifacial Microsomia Postmandibular Distraction Osteogenesis.

OBJECTIVE: Mandibular distraction osteogenesis (MDO) is a powerful tool for the correction of hemifacial microsomia (HFM). The temporomandibular joint (TMJ) is the focus of attention in the diagnosis and treatment of HFM. This observational retrospective cross-sectional study aimed to investigate morphologic changes in TMJ post-MDO in type IIa HFM. METHODS: We recruited 48 patients with unilateral type IIa HFM who had completed MDO and mandibular distractor extraction (MDE). Data relating to the length, distance, angle, and volume of the TMJ were measured on 3-dimension models created by the analysis of computed tomography data. Normality analysis was performed by using the Shapiro-Wilk test. Data were compared with the paired t test and Wilcoxon signed-ranks test. RESULTS: The spaces between the affected condyle and the affected glenoid fossa before MDO were all significantly larger than before MDE (P<0.05). The breadth of the affected glenoid fossa before MDO was significantly longer than before MDE (P<0.001). The height of the affected condyle before MDO was significantly longer than before MDE (P<0.001). The volume of the affected condyle before MDO was significantly larger than before MDE (P<0.001). The ratio between the volume of the affected condyle and unaffected condyle before MDO was 0.20±0.13. The ratio between the volume of the affected condyle before MDE and MDO was 0.65±0.32. The resorption rate of the affected condyle post-MDO was 0.35±0.32. CONCLUSION: Herein, we characterized anatomic changes of the TMJ in type- IIa HFM post-MDO. Condylar resorption and the compression of space between the condyle and the glenoid fossa on the affected side were 2 typical manifestations. Our findings enhanced the understanding of the application of MDO on HFM.

Condylar resorption post mandibular distraction osteogenesis in craniofacial microsomia: A retrospective study.

The aim of this study was to investigate the characteristics of condylar resorption in craniofacial microsomia (CFM) patients following mandibular distraction osteogenesis (MDO). Patients with unilateral type-IIa and type-IIb CFM, who had completed MDO and mandibular distractor extraction (MDE), were recruited. The height and volume of the condyle were measured on three-dimension models created by the analysis of computed tomography (CT) data. Normality analysis was performed using the Shapiro-Wilk test. Data for the affected and unaffected sides were compared using the paired t-test or Wilcoxon signed-rank test. Data for both type-IIa and type-IIb CFM were compared using the independent-samples t-test or Mann-Whitney U test. The Pearson or Spearman correlation was used to determine the correlations of condylar resorption rate with related measurements. In total, 48 type-IIa and 48 type-IIb CFM patients were included. The condylar resorption rate in type-IIa CFM (0.35 ± 0.32) was significantly associated with the height of the condyle (r = 0.776, p < 0.001) and distraction distance (r = 0.447, p = 0.001), while the condylar resorption rate in type-IIb CFM (0.49 ± 0.46) was significantly associated with the height of the condyle (r = 0.924, p < 0.001). However, there was no significant difference in condylar resorption rate between type-IIa and type-IIb CFM (p = 0.075). In addition to occlusal changes, no other negative symptoms of the TMJ were observed with condylar resorption. Condylar resorption was evident in CFM patients following mandibular distraction osteogenesis, and the condylar resorption rate showed a relationship with distraction distance and condylar height.

Three-Dimensional Morphology and Configuration Analyses of the Craniovertebral Junction in Children with Hemifacial Microsomia.

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.Level of Evidence: N/A.