Hemifacial Microsomia Patients Research Articles

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

BackgroundMandibular 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.MethodsThis 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.DiscussionThis 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 registrationChinese Clinical Trial Registry ChiCTR2200061565. Registered on 29 June 2022.

Integrating Virtual Surgical Planning and 3D-Printed Tools with Iliac Bone Grafts for Orbital and Zygomatic Reconstruction in Hemifacial Microsomia Patients.

Hemifacial Microsomia (HFM) is the second most common congenital craniofacial malformation syndrome, and the complexity of HFM makes its treatment challenging. The present study aimed to introduce a new approach of utilization of virtual surgical planning (VSP) and 3D-printed surgical adjuncts for maxillofacial reconstruction. Five HFM patients were included in this study. All participants were provided with a full VSP, including the design of osteotomy lines, the design and fabrication of 3D-printed cutting guides, fixation plates, and titanium mesh for implantation. With the assistance of 3D-printed cutting guides and fixation plates, the orbital deformities were corrected, and a 3D-printed titanium mesh combined with iliac cancellous bone graft was applied to reconstruct the zygomatic arch. The surgical accuracy, effectiveness, and bone absorption rate were evaluated. All patients completed the entirely digital treatment process without experiencing severe complications. The surgical adjuncts were effective in aligning the movement of the bone segments with the surgical plan, resulting in mean 3D deviations (1.0681 ± 0.15 mm) and maximum 3D deviations (3.1127 ± 0.44 mm). The image fusion results showed that the patients' postoperative position of the maxilla, zygoma, and orbital rim was consistent with the virtual surgical plan, with only a slight increase in the area of bone grafting. The postoperative measurements showed significant improvement in the asymmetry indices of Er (AI of Er: from 17.91 ± 3.732 to 5.427 ± 1.389 mm, p = 0.0001) and FZ (AI of FZ: from 7.581 ± 1.435 to 4.070 ± 1.028 mm, p = 0.0009) points. In addition, the observed bone resorption rate at the 6-month follow-up across the five patients was 45.24% ± 3.13%. In conclusion, the application of VSP and 3D-printed surgical adjuncts demonstrates significant value in enhancing the precision and effectiveness of surgical treatments for HFM. A 3D-printed titanium mesh combined with iliac cancellous bone graft can be considered an ideal alternative for the reconstruction of the zygomatic arch.

Virtual planning for corrections of hemifacial microsomia

Abstract Objectives This article describes the many anomalies within and outside the head and neck of hemifacial microsomia (HFM). Methods The OMENS+ classification system is described with particular reference to the mandibular features classified by Pruzansky and modified by Kaban. The application of virtual surgical planning (VSP) to HFM, largely in children, is described and taken through to aspects indicated in maturity. Results VSP is demonstrated with clinical cases examples in HFM patients for (1) grafts and flaps replacing missing parts of the zygomatic bone, temporo-mandibular joint and mandible, (2) distraction osteogenesis for lengthening of the mandibular ramus, advancement of the mandibular body, widening of the face and simultaneous mid-face and mandibular rotation, (3) implants and correction of microtia for bone anchored ear prostheses, (4) correction of microtia by autogenous ear construction, and (5) end stage rotational bimaxillary osteotomies. Conclusions 3D virtual and physical planning is a valuable adjunct to the treatment of this complex condition.

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

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. 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. 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. 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.

Utilization of extended temporomandibular joint replacements in patients with hemifacial microsomia

Hemifacial microsomia (HFM) patients may benefit from extended temporomandibular joint replacements (eTMJR) to improve function and quality of life. A cross-sectional survey was sent to surgeons who place alloplastic temporomandibular joints regarding their experience with and complications encountered when placing eTMJR in patients with HFM. Fifty-nine responded to the survey. Thirty-six (61.0%) reported treating patients with HFM and 30 (50.8%) of those reported placing an alloplastic temporomandibular joint (TMJ) prosthesis for patients with HFM. Twenty-three of the 30 surgeons (76.7%) placing alloplastic TMJ prostheses reported using an eTMJR in patients with HFM. The average maximum inter-incisal opening (MIO) after an eTMJR in HFM patients was repor ted as> 25 mm by 82.6% of the participants, and between 16 mm and 25 mm by 17.4%. No participants reported MIO < 15 mm. To avoid condylar sag and open bite changes postoperatively, over 70% reported using some form of modification to stabilize the occlusion. Respondents reported good functional outcomes for eTMJR in patients with HFM with relatively few complications. Therefore, eTMJR could be considered a viable option in the management of this patient population.

Kaban-Pruzansky Grade Predicts Airway Severity in Hemifacial Microsomia.

Children born with hemifacial microsomia (HFM) can experience airway compromise. There is a paucity of data correlating degree of HFM severity with airway difficulty. This study aims to determine the relationship between the degree of micrognathia and airway insufficiency in the HFM population. Patient demographics, airway function, Kaban-Pruzansky (KP) grade, and Cormack-Lehane (CL) grade were collected and compared with appropriate statistics for HFM patients treated between 2000 and 2022. Seventy patients underwent 365 operations with KP grading as follows: 34% KP grade I, 23% KP grade IIA, 11% KP grade IIB, and 33% KP grade III. Goldenhar syndrome was present in 40% of patients and 16% had bilateral disease. KP grade ( P < 0.001) predicted mean number of airway-affecting procedures undergone and difficult airway status ( P < 0.001), with 75% of difficult airways in KP grade III patients. There was no association of airway compromise with Goldenhar syndrome, laterality, or age ( P > 0.05). Most CL grades were I (61%) or IIA (13%), with fewer grade IIB, grade III, and grade IV (4% to 7%). KP grade predicted CL grade ( P < 0.001), with 71% of grade IV views and 64% of grade III views seen in KP grade III patients. KP grade correlated with airway severity in HFM. Patients do not appear to outgrow their CL grade, as previously hypothesized, suggesting that KP grade III patients remain at increased risk for airway insufficiency into the teen years. Given the potential significant morbidity associated with airway compromise, proper identification and preparation for a challenging airway is a critical part of caring for patients with HFM. Risk, III.

A Proposal for the Classification of Temporomandibular Joint Disc Deformity in Hemifacial Microsomia.

Hemifacial microsomia (HFM) is the second most common congenital craniofacial disease and has a wide spectrum of symptoms. The classic diagnostic criterion for hemifacial microsomia is the OMENS system, which was later refined to the OMENS+ system to include more anomalies. We analyzed the data of 103 HFM patients with magnetic resonance imaging (MRI) for temporomandibular joint (TMJ) discs. The TMJ disc classification was defined into four types: D0 for normal disc size and shape; D1 for disc malformation with adequate length to cover the (reconstructed) condyle; D2 for disc malformation with inadequate length to cover the (reconstructed) condyle; and D3 for no obvious presence of a disc. Additionally, this disc classification was positively correlated with the mandible classification (correlation coefficient: 0.614, p < 0.01), ear classification (correlation coefficient: 0.242, p < 0.05), soft tissue classification (correlation coefficient: 0.291, p < 0.01), and facial cleft classification (correlation coefficient: 0.320, p < 0.01). In this study, an OMENS+D diagnostic criterion is proposed, confirming the conjecture that the development of the mandibular ramus, ear, soft tissue, and TMJ disc, as homologous and adjacent tissues, is affected to a similar degree in HFM patients.

D157. Using Orthodontic Elastic Traction During the Active Period of Distraction Osteogenesis to Increase the Effective Vertical Extension of Hemifacial Microsomia Patients: A Multi-center Randomized Clinical Trial

PURPOSE: In this study, the aim was to assess whether using elastic traction during the active period of distraction osteogenesis could effectively increase the vertical extension. METHODS: Patients with Pruzansky-Kaban Type II mandibular deformity were recruited and randomly assigned into Elastic traction + Distraction Osteogenesis group or Distraction Osteogenesis group, respectively. During the active period, the experimental group received orthodontic elastic traction 3 days after distraction osteogenesis implantation, while the control group received no treatment. All the participants underwent computed tomography (CT) examination before surgery, at the end of the active period, 6 months and 2 years after distraction osteogenesis tractor implantation. The primary outcome was the effective vertical extension rate of the mandible from the baseline to the end of the active period after operations, and there were 7 secondary outcomes used. RESULTS: 70 patients were included. The effective vertical extension rates were 85.021% ± 7.432% and 68.811% ± 9.510% in the experimental and control groups, respectively (P = 0.001). The average distances between the lower middle incisor point to the sagittal plane at the end of the active period were 2.485 ± 1.411 mm and 3.938 ± 2.293 mm in the experimental and control groups, respectively (P = 0.026). At the end of the active period of distraction osteogenesis, the average values of the mandibular occlusal plane canting were -4.887 ± 3.126 mm and -0.177 ± 4.029 mm in the experimental and control groups, respectively (P = 0.026). CONCLUSION: Elastic traction-assisted distraction osteogenesis could improve traction efficiency and facial symmetry.

Transcriptome sequencing of facial adipose tissue reveals alterations in mRNAs of hemifacial microsomia.

Hemifacial microsomia (HFM) is a common congenital malformation of the craniofacial region, including mandibular hypoplasia, microtia, facial palsy and soft tissue deficiencies. However, it remains unclear which specific genes are involved in the pathogenesis of HFM. By identifying differentially expressed genes (DEGs) in deficient facial adipose tissue from HFM patients, we hope to provide a new insight into disease mechanisms from the transcriptome perspective. RNA sequencing (RNA-Seq) was performed with 10 facial adipose tissues from patients of HFM and healthy controls. Differentially expressed genes in HFM were validated by quantitative real-time PCR (qPCR). Functional annotations of the DEGs were analyzed with DESeq2 R package (1.20.0). A total of 1,244 genes were identified as DEGs between HFM patients and matched controls. Bioinformatic analysis predicted that the increased expression of HOXB2 and HAND2 were associated with facial deformity of HFM. Knockdown and overexpression of HOXB2 were achieved with lentiviral vectors. Cell proliferation, migration, and invasion assay was performed with adipose-derived stem cells (ADSC) to confirm the phenotype of HOXB2. We also found that PI3K-Akt signaling pathway and human papillomavirus infection were activated in HFM. In conclusion, we discovered potential genes, pathways and networks in HFM facial adipose tissue, which contributes to a better understanding of the pathogenesis of HFM.

Exploration of Novel Genetic Evidence and Clinical Significance Into Hemifacial Microsomia Pathogenesis

The authors browsed through past genetic findings in hemifacial microsomia along with our previously identified mutations in ITGB4 and PDE4DIP from whole genome sequencing of hemifacial microsomia patients. Wondering whether these genes influence mandibular bone modeling by regulation on osteogenesis, the authors approached mechanisms of hemifacial microsomia through this investigation into gene knockdown effects in vitro. MC3T3E1 cells were divided into 5 groups: the negative control group without osteogenesis induction or siRNA, the positive control group with only osteogenesis induction, and 3 gene silenced groups with both osteogenesis induction and siRNA. Validation of transfection was through fluorescence microscopy and quantitative real-time Polymerase chain reaction on knockdown efficiency. Changes in expression levels of the 3 genes during osteogenesis and impact of Itgb4 and Pde4dip knockdown on osteogenesis were examined by quantitative real-time Polymerase chain reaction, alkaline phosphatase, and alizarin red staining. Elevation of osteogenic genes Alpl, Col1a1, Bglap, Spp1, and Runx2 verified successful osteogenesis. Both genes were upregulated under osteogenic induction, while they had different trends over time. Intracellular fluorophores under microscope validated successful transfection and si-m-Itgb4_003, si-m-Pde4dip_002 had satisfactory knockdown effects. During osteogenesis, Pde4dip knockdown enhanced Spp1 expression (1.95±0.13 folds, P =0.045). The authors speculated that these genes may have different involvements in osteogenesis. Stimulated expression of Spp1 by Pde4dip knockdown may suggest that Pde4dip inhibits osteogenesis.

Determination of Novel, Cranium-Based Relationships for Construct Placement in Microtia Reconstruction for Hemifacial Microsomia Patients.

Determine if the ideal location of the construct in microtia reconstruction for hemifacial microsomia (HFM) can be more accurately derived from measurements on the cranium. High-resolution computerized tomography (CT) images were analyzed through craniometric linear relationships. Our tertiary care institution from 2000 to 2021. Patients diagnosed with HFM and microtia, who had high-resolution craniofacial CT scans, yielding 36 patients accounting for 44 CT scans. First, the integrity of the posterior cranial vault among HFM patients was determined. If proven to be unaffected, it could be used as a reference in the placement of the construct. Second, the position of the ear in relation to the cranium was assessed in healthy age-matched controls. Third, if proven to be useful, the concordance of these cranium-based relationships could be validated among our HFM cohort. The posterior cranial vault is unaffected in HFM (P > .001). Further, craniometric relationships between the tragus and the Foramen Magnum, as well as between the tragus and the posterior cranium, have been shown to be highly similar and equally precise in predicting tragus position in healthy controls (P > .001). These relationships held true across all age groups (P > .001), and importantly among HFM patients, where the mean absolute difference in predicted tragus position never surpassed 1.5 mm. Relationships between the tragus and the cranium may be used as an alternative to distorted facial anatomy or surgeon's experience to assist in pre-operative planning of construct placement in microtia reconstruction for HFM patients.

Surgical Microtia Reconstruction in Hemifacial Microsomia Patients: Current State and Future Directions.

Background:Hemifacial microsomia (HFM) is one of the most common congenital craniofacial disorders. Among many other features, microtia is present in the large majority of these patients. However, mainly due to the unilateral hypoplastic anatomy, microtia reconstruction among this patient population remains a reconstructive challenge for plastic surgeons. Given that no clear standards exist, an evidence-based synthesis of the literature was devised.Methods:A systematic search of Pubmed, Medline, and Embase was carried out, in accordance with the PRISMA guidelines. Studies discussing surgical microtia reconstruction for HFM patients were retained. Qualitative data regarding study design, challenges addressed, specific recommendations, and their respective strengths/limitations were extracted from each. Retrieved recommendations were consolidated and assigned a level of evidence grade.Results:Although only 11 studies were included in this review, these provided 22 main recommendations regarding the eight HFM-specific challenges identified, which were of either grade C (n = 5) or D (n = 17). Included studies addressed construct location (n = 7), the low hairline (n = 6), soft tissue construct coverage (n = 6), earlobe reconstruction (n = 6), construct projection (n = 5), anomalies of the relevant neurovascular systems (n = 2), retroauricular construct coverage (n = 2), and sizing of the construct (n = 2).Conclusions:Given the many persisting reconstructive challenges regarding surgical microtia reconstruction for HFM patients, the authors present a comprehensive and evidence-based consolidation of recommendations specific to these challenges. The authors hope this systematic review can appropriately guide plastic surgeons and will ultimately improve care for this patient population.

Three-dimensional measurements on the mandible of patients with hemifacial microsomia.

Background:Hemifacial microsomia (HFM), which involves multiple sites with different levels of severity, is the second most common congenital craniofacial deformity after cleft lip and palate. However, three-dimensional (3D) measurements of mandibular deformities have not yet been studied in detail. The objective of this study is to investigate the method of 3D measurements of mandibular deformities in HFM patients.Methods:A total of 48 HFM patients were included in this study. All clinical treatment for patients was performed in the Plastic Surgery Hospital of the Chinese Academy of Medical Sciences at Peking Union Medical College from June 2006 to June 2020. The patients’ 3D computerized tomography scan data were processed using medical imaging software, following four iterative steps: 3D reconstruction, mirroring, differential analysis, and partition.Results:The characteristics of the mandibular bone in HFM patients are mainly presented as follows: (1) compared to the normal side, the part of the bone body that extends from the ascending ramus to the pogonion (Po-NB) is analyzed using a dynamic process: less fullness-fullness-more fullness; (2) absences were frequently observed among the angular zones, that is, the height of the ascending ramus is deficient.Conclusions:HFM is a complicated condition with numerous variations in clinical presentation. We employed both 3D image reconstruction and computerization image processing techniques to investigate asymmetrical mandibular deformity in HFM patients in detail and with great accuracy. This will be of great use to clinicians for disease management.

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

Observational and morphological study with three-dimensional (3D) computed tomography (CT) analysis. 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. The evaluation for cervical vertebrae anomaly in HFM children, especially in CVJ region, is underreported. 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. 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). 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.

A new treatment strategy for hemifacial microsomia: Auricular reconstruction with an expanded two-flap method and simultaneous mandibular distraction osteogenesis

Owing to the complex clinical manifestations of hemifacial microsomia (HFM), multidisciplinary cooperation is required to achieve better therapeutic effects in terms of function and aesthetics. This study aimed to explore the efficacy of the expanded two-flap auricular reconstruction combined with mandibular distraction osteogenesis in the treatment of HFM. This surgical strategy was performed in three stages. In the first stage, the retroauricular skin was expanded with a tissue expander and a mandibular distraction device was installed. In the second stage, the traditional expanded two-flap method for auricular reconstruction was adapted, and the framework was fabricated with costal cartilage and wrapped with the expanded skin flap, retroauricular fascia flap, and full-thickness skin graft. In the final stage, the tragus and lobule were rebuilt, the concha cavity deepened, and the mandibular distraction device removed. From January 2014 to November 2018, 166 HFM patients underwent auricular reconstruction with the expanded two-flap method and simultaneous mandibular extension in our hospital. The median follow-up period was 9.3 months. Of the 166 patients, 154 patients and their families were satisfied with the results, and only 16 patients experienced complications. This three-stage technique of simultaneous auricular reconstruction and mandibular distraction osteogenesis is safe and effective in achieving facial symmetry, improving occlusal contact, shortening treatment course, and relieving patient's suffering, especially for HFM patients.

What is the impact of distraction osteogenesis on the upper airway of hemifacial microsomia patient with obstructive sleep apnea: a case report

BackgroundCurrent research about hemifacial microsomia (HFM) patients after distraction osteogenesis (DO) most emphasize the morphologic changes. This case report shows the outcome of DO on the upper airway of a HFM patient with obstructive sleep apnea (OSA) based on the use of computational fluid dynamics (CFD).Case presentationAn 11-year-old boy was diagnosed as HFM with OSA, and underwent unilateral DO. Polysomnography and CT scans were performed before and 6 months after treatment. After DO, lowest blood oxygen saturation increased from 81% to 95% and apnea and hypopnea index decreased from 6.4 events/hour to 1.2 events/hour. The oropharynx and nasopharynx were obviously expanded. We observed apparently increased average pressure, decreased average velocity and pressure drop in all cross-sections, and largely decreased airflow resistance and maximum velocity entirely in the airway.ConclusionsThe results suggest that DO might be effective for the treatment of OSA by expanding the upper airway and reducing the resistance of inspiration.

The Stress Concentration and Biomechanical Properties of the Intraoral Distractors and the Extraoral Distractors Used in Treatment of Hemifacial Microsomia Patients: A Simulation Finite Element Analysis Study.

Finite element analysis of the stresses subjected to both the intraoral and the extraoral distractors devices used in the mandibular distraction of hemifacial microsomia patients. Two models were included in the current study. The first model was an extraoral distractor and the second model was an intraoral distractor model. To generate the results in the simulated models; 2 vertical loads were applied (222.7 and 137.78 N) on the defective and normal side, respectively. The intraoral system observed lower stress (6.85 MPa) in the mandibular bone compared to the extraoral system (13.21 MPa). The intraoral distractor had a higher stress concentration on the distractor fixing screws (352 MPa) compared to the extraoral distractor fixing pins (15 MPa). The extraoral distractor had a higher displacement effect on the mandibular bone around the pins of 263.35 μm in comparison to the intraoral distractor effect which was 77.87 μm. Internal oral distractor provides a sort of stress shielding to the distracted bone and less displacement, so it is more advisable to be used in general. The external devices are advised only in extralong distraction distance because the distractor is subjected to lower stresses compared to intraoral counterparts.

Using orthodontic elastic traction during the active period of distraction osteogenesis to increase the effective vertical extension of hemifacial microsomia patients: A multi-center randomized clinical trial

In this study, the aim was to assess whether using elastic traction during the active period of distraction osteogenesis could effectively increase the vertical extension.Patients with Pruzansky-Kaban Type II mandibular deformity were recruited and randomly assigned into Elastic traction + Distraction Osteogenesis group or Distraction Osteogenesis group, respectively. During the active period, the experimental group received orthodontic elastic traction 3 days after distraction osteogenesis implantation, while the control group received no treatment. All the participants underwent computed tomography (CT) examination before surgery, at the end of the active period, 6 months and 2 years after distraction osteogenesis tractor implantation. The primary outcome was the effective vertical extension rate of the mandible from the baseline to the end of the active period after operations, and there were 7 secondary outcomes used.70 patients were included. The effective vertical extension rates were 85.021% ± 7.432% (mean ± SD) and 68.811% ± 9.510% (mean ± SD) in the experimental and control groups, respectively (P = 0.001). The average distances between the lower middle incisor point to the sagittal plane at the end of the active period were 2.485 ± 1.411 mm and 3.938 ± 2.293 mm in the experimental and control groups, respectively (P = 0.026). At the end of the active period of distraction osteogenesis, the average values of the mandibular occlusal plane canting were −4.887 ± 3.126 mm and −0.177 ± 4.029 mm in the experimental and control groups, respectively (P = 0.026).Elastic traction-assisted distraction osteogenesis could improve traction efficiency and facial symmetry.

Outcome of surgical-orthodontic treatment in hemifacial microsomia with and without early mandibular distraction osteogenesis

The aim of this study was to compare the outcomes of surgical-orthodontic treatment between hemifacial microsomia (HFM) patients who had and had not undergone early mandibular distraction osteogenesis (DO). Twenty adult unilateral HFM patients were included, seven who had undergone early mandibular DO (DO group) and 13 who had not (NDO group). All patients were type IIB, except for one type IIA patient in the NDO group. Mean age at definitive surgery was 20.72±2.96 years. Linear, cross-sectional, and volumetric measurements were obtained from serial cone beam computed tomography scans. Data were obtained pre-surgery (T0), 1 week after surgery (T1), and at treatment completion (T2) to determine surgical movement, post-surgical stability, and net gain movement. Surgical and ultimate outcomes did not differ significantly between the groups. The overall surgical movement among all patients was as follows (mean values): maxillomandibular complex (MMC) symmetry was achieved by Le Fort I differential roll movement (3.78mm extrusion on the affected side, 4.28mm impaction on the non-affected side), a combination of medial movement and yaw rotation of MMC, and genioplasty. Upper and lower dental midlines and deviated menton were shifted by 5.73mm, 5.08mm, and 12.38mm, respectively. Anterior impaction and advancement with counterclockwise rotation of MMC were also performed. Menton was advanced by 6.14mm and lower facial height was increased by 3.55mm. Neither group exhibited a significant difference in stability. Relapse at the maxilla was <1mm and relapse at the mandible was <1.5mm. The results suggest that early DO had limited beneficial effects on the definitive correction outcome. HFM patients achieved acceptable symmetry and a stable surgical outcome, regardless of early DO, following surgical-orthodontic correction at skeletal maturity with three-dimensional surgical simulation.

Computer-aided design and manufacturing construction of a pilot guide for a bone-anchored epithesis to replace an absent pinna

Bone-anchored epitheses have acquired an important role in auricle reconstruction. The purpose of this technical note is to present a fully in-house digital workflow for the design and three-dimensional (3D) printing of an optimal ear epithesis guide. Two hemifacial microsomia patients with grade IV microtia were treated accordingly. The upper dental arch was optically scanned and a cone beam computed tomography scan of the cranium was obtained. The composite and soft tissue models created were exported into 3D sculpting software. The unaffected ear was virtually mirrored onto the affected side and two ideal implant positions were defined in relation to bone thickness, contralateral symmetry, and housing of the retaining bar. A bite wafer was virtually designed on the upper dental arch and connected to the mirrored ear. The pilot guide was 3D-printed and allowed for correct positioning and orientation during surgery. The prosthetic pinna was manufactured in a conventional way. A bar with retaining clips was used to anchor the prosthetic pinna. Clinically satisfactory results were obtained in two grade IV microtia cases. The fully digital workflow presented to design and 3D-print an optimal ear epithesis guide offers a good alternative to the existing techniques.