Three-dimensional chest computed tomography analysis of thoracic deformities in patients with microtia

A Systematic Review of the Application of Computational Technology in Microtia

Microtia is a congenital and morphological anomaly of one or both ears, which results from a confluence of genetic and external environmental factors. Up to now, extensive research has explored the potential utilization of computational methodologies in microtia and has obtained promising results. Thus, the authors reviewed the achievements and shortcomings of the research mentioned previously, from the aspects of artificial intelligence, computer-aided design and surgery, computed tomography, medical and biological data mining, and reality-related technology, including virtual reality and augmented reality. Hoping to offer novel concepts and inspire further studies within this field.

Coronal, Sagittal, and Horizontal Classification of the Chest Shape and Its Role in Selection of Proper Implants

Background

The number of female breast correction procedures has been steadily increasing. Despite extensive literature being available on these procedures, few authors have discussed the role of preoperative chest wall analysis in relation to postoperative outcomes. To date, no comprehensive classification of chest shape has been introduced in the literature. The aim of this study was to present a novel classification of chest shapes, based on three basic planes: coronal (C), sagittal (S), and horizontal (H), hence the proposed name "CSH classification."

Method

In this study, a retrospective analysis of 1000 randomly selected chest and breast images was conducted by three independent nonmedical evaluators, using standardized digital images captured with the Vectra 3D body scanner. All examined patients were qualified for breast augmentation surgery.

Results

Among 1000 randomly examined patients, 923 were classified in the coronal plane, 920 in the sagittal plane, and 627 in the horizontal plane. Other patients were excluded from the study due to insufficient quality of the images. A notable 43.2% of women have shoulder height asymmetries. A relationship between shoulder height asymmetry and chest width was confirmed by the chi-square Pearson test (P = 0.04), indicating that a higher shoulder is associated with a greater chest width on the same side. Furthermore, 84.7% of women displayed excessive upper chest projection, whereas 28.4% showed excessive lower chest projection. Additionally, 84.4% of women had chest projection asymmetries.

Conclusions

The vast majority of the women had natural asymmetries of the breast or and chest wall. The CSH classification allows systematizing the chest shape assessment. The chest shape has a significant impact on breast implant selection and the choice of the breast surgery technique.

Inheritance analysis and family history for microtia: A hospital-based study in China

OBJECTIVES

Microtia is a congenital anomaly of the outer ear. Although genetic and environmental factors could play a role, no consensus has been established on the pathogenesis and cause of this condition. In this study, we surveyed the frequency and pattern of family history in patients with microtia in a Chinese specialty clinic population.

METHODS

We evaluated data from 672 patients (mean age = 9.2, male-to-female ratio = 2.6:1) with microtia admitted to the Department of Auricular Reconstruction at the Plastic Surgery Hospital of Peking Union Medical College from December 2014 to February 2016. Family history of congenital ear anomalies across three generations was recorded. Pearson chi-square test or Fisher exact test was used to test the associations between the characteristics of microtia and hereditary features.

RESULTS

A family history of auricle anomalies was identified in 202 patients (30.1%), of whom, 95 families showed vertical transmission, 14 families skipped a generation, and 120 families showed family aggregations. The incidence of family history varied with grades of microtia (P = 0.001). Patients with preauricular tags or pits (38.3%) had a higher familial incidence of microtia than those with simple microtia (24.1%) (P < 0.001).

CONCLUSION

Patients with a lower grade of microtia demonstrated a higher incidence of family history. Patients with microtia had significantly more relatives with preauricular tags or pits. Microtia and preauricular tags or pits are different manifestations of the same defect, and their significant concurrency among relatives suggests that a considerable proportion of microtia is inherited and could recur with varying degrees of severity in other family members.

Vertebral Anomalies in Microtia Patients at a Tertiary Pediatric Care Center

OBJECTIVE

Microtia is a congenital condition known to be associated with vertebral anomalies and congenital syndromes, most prominently hemifacial microsomia. There is controversy, however, on whether to screen with spinal imaging. Additionally, microtia ear reconstruction utilizes rib harvesting that could potentially worsen pre-existing vertebral and rib anomalies, specifically scoliosis. We report on the prevalence and characteristics of vertebral anomalies among microtia patients at a tertiary pediatric center.

STUDY DESIGN

Retrospective case review with literature review.

SETTING

Tertiary pediatric referral center.

METHODS

A review of 425 children with microtia was conducted, characterized as either syndromic or nonsyndromic. Data included demographics, spinal imaging performed, indications, anomalies detected, and microtia repair.

RESULTS

Among 425 microtia patients, 24.5% were syndromic with an average age of 9.7 years. Only 18.4% of all patients had spinal imaging performed (50% syndromic vs 8.1% nonsyndromic). Overall, 10.6% had a vertebral anomaly with a 57.7% detection rate (67.3% syndromic vs 38.5% nonsyndromic). The most common anomaly was scoliosis, with a prevalence of 7.8%. Fusion defects and rib deformities were the next most prominent. Microtia repair, most commonly with an autologous rib graft, was performed in 21.6% of the cohort. However, only 19.2% had spinal imaging and 16.7% with a vertebral anomaly.

CONCLUSION

Children with microtia are at a greater risk of vertebral abnormalities. Scoliosis prevalence in isolated microtia is comparable to the general population (2%-3%) but greatly increased with genetic syndromes. Screening for vertebral anomalies should be considered when planning microtia reconstructions, especially in the syndromic population.

Whole genome sequencing analysis of four patients: Are de novo copy number variations in non-coding region responsible for microtia with lung hypoplasia?

BACKGROUND

Microtia is a congenital malformation of the out ear, occurring either as an isolated defect or part of a specific pattern of multiple congenital anomalies. The etiology of microtia is poorly understood. Four patients with microtia and lung hypoplasia were reported by our team in a previous article. The purpose of this study was to identify the underlying genetic basis, mainly focusing on de novo copy number variations (CNVs) embedded in the noncoding region, in the four subjects.

METHODS

DNA samples from all four patients and their unaffected parents were extracted for whole-genome sequencing on the Illumina platform. All variants were obtained through data quality control, variant calling and bioinformatics analysis. De novo strategy was used to prioritize the variants, and candidate variants were verified by PCR amplification combined with Sanger sequencing and visual inspection of bam file.

RESULTS

Whole gene sequencing following bioinformatics analysis showed no potential de novo pathogenic variants in the coding region. Nonetheless, four de novo CNVs in the non-coding region, intronic or intergenic, were identified in each subject, ranging in size from 10 Kb to 12.5 Kb, and all are deletions. Case 1 had a de novo deletion of 10 Kb on chromosome10q22.3, located in the intronic region of the LRMDA gene. The other three cases all had a de novo deletion in intergenic regions, located on chromosome 20q11.21, 7q31.1 and 13q12.13, respectively.

CONCLUSIONS

This study reported multiple long-lived cases of microtia with pulmonary hypoplasia and provided genome-wide genetic analysis focusing on de novo mutations. Whether the de novo CNVs identified are responsible for the rare phenotypes remains an open question. However, the results of our study provided a new perspective that the unsolved etiology of microtia might involve in non-coding sequences, which have long been ignored.

Quantitative Analysis on Cartilage Growth Between Ipsilateral and Contralateral Donor Sites in Microtia Patients

BACKGROUND

Costal cartilage harvest is required in patients with unilateral microtia when autologous reconstruction is being considered. However, whether an ipsilateral or contralateral donor site should be used remains controversial. This is the first study to compare cartilaginous growth between ipsilateral and contralateral donor sites in patients with unilateral microtia.

METHODS

In this retrospective study of 58 patients, the lengths of the sixth to ninth costal cartilages and 3 position-defining measurements with respect to the sixth to ninth costochondral junctions were calculated using 3-dimensional costal cartilage imaging. Patients were divided into subgroups, and the lateral differences between isolated microtia and hemifacial microsomia and between the growing and adult age groups, were compared.

RESULTS

In the isolated group, the sixth and seventh costal cartilages were longer on the contralateral side. The transverse dimension on the contralateral side, with respect to the sixth and seventh costochondral junctions, was also larger than that on the ipsilateral side in growing patients. However, no significant difference was observed between the 2 sides in the hemifacial microsomia group; there was also no difference between the age-related groups in this regard (P > 0.05).

CONCLUSIONS

These findings suggest that age- and side-related differences in donor sites should be considered in patients with isolated microtia.

Evaluation of respiratory system anomalies associated with microtia in a Chinese specialty clinic population

BACKGROUND

Microtia is a congenital malformation of the external ear often with one or more associated congenital anomalies. The purpose of this study was to identify the characteristics and prevalence of respiratory anomalies in patients with microtia, and clarify the importance of this association in the perioperative period of patients' external ear reconstruction surgery.

METHODS

Data were collected from 923 microtia patients between August 2017 and December 2020 in the Department of Auricular Reconstruction at the Plastic Surgery Hospital of Peking Union Medical College. Co-occurring respiratory anomalies were detected using chest computed tomography plus three-dimensional reconstruction and Chest X-ray. Physical examination was performed to assess the severity and type of microtia by trained clinicians. Fisher's exact test was used to analyze the relation between laterality of pulmonary underdevelopment and microtia type.

RESULTS

Among the 923 participants enrolled in the study, we identified 21 cases (2.3%) having respiratory system anomalies, consisting of 6 cases with pulmonary underdevelopment (28.6% of all anomalies of respiratory system detected), 2 cases with tracheal bronchus (9.5%), 1 case with tracheal diverticula (4.8%), 11 cases with lung bullae(52.4%), and 1 case with pulmonary azygos lobe (4.8%). The laterality of pulmonary underdevelopment was related to the type of microtia (difference between types, p < 0.05), as patients with concha-type remnant ear had pulmonary underdevelopment ipsilaterally.

CONCLUSIONS

This study represents the first detailed and thematic study of a association featured by microtia and respiratory anomalies. Characteristics and prevalence of respiratory anomalies was observed in a Chinese clinical microtia population. Early diagnosis of associated respiratory malformations had practical clinical significance for microtia patients, plastic surgeons and anesthesiologists. Future studies are required to improve understanding of this association and its cause.

Whole-exome sequencing analysis in 10 families of sporadic microtia with thoracic deformities

Background

Microtia is a congenital malformation of the external ear and may occur as an isolated deformity or as part of a syndrome. Our previous study found a high correlation between microtia and thoracic deformities, thus, we propose that external ear and thorax development may be regulated by certain genes in common.

Methods

We performed exome sequencing on 10 families of sporadic microtia with thoracic abnormalities. We identified mutated genes under different models of inheritance, and checked them through Mouse Genome Informatics and association analysis.

Results

We identified 45 rare mutations, including 9 de novo mutations, 20 heterozygous mutations, 3 homozygous mutations, and 13 hemizygous mutations, of which 2 are likely to be causative. They are de novo missense variant in PHF5A and compound heterozygous mutations in CYP26B1, of which CYP26B1 mutation is highly likely pathogenic.

Conclusion

The results indicate that certain genes may affect both external ear and thorax development, and demonstrate the benefits of whole‐exome sequencing in identifying candidate genes of microtia. This study provides a new way for genetic exploration in microtia.

Validity and reliability of three-dimensional costal cartilage imaging for donor-site assessment and clinical application in microtia reconstruction patients: A prospective study of 22 cases

OBJECTIVES

This study assesses the ability to reconstruct costal cartilage images by using three-dimensional visualisation software (Mimics) based on semi-automated segmentation algorithm and to investigate its reliability and validity with an anthropometric analysis.

DESIGN

Observational prospective study.

SETTING

Plastic surgery department of a tertiary hospital.

PARTICIPANTS

Twenty-two microtia patients who underwent autologous ear reconstruction.

MAIN OUTCOME MEASURES

Preoperative thoracic computed tomography data were processed to Mimics software for three-dimensional costal cartilage imaging. The length, width, thickness and volume of the 9th costal cartilages were calculated from these images and compared with the direct measurements (DM) obtained intraoperatively.

RESULTS

The intra-examiner reliability and inter-examiner reliability were high in terms of all four measurements (intraclass correlation coefficients, ICC: 0.876-0.984). There were no significant differences between image-based anthropometry and DM in the linear measurements except for the volume (P < .05). The mean volume calculation error of Mimics was -0.08 ± 0.13 mL. No correlation was found between the anthropometric variables and the absolute errors (P > .05). Furthermore, Bland-Altman plots were used to evaluate the agreement between the two methods.

CONCLUSIONS

Despite a very small error was found in volume calculation, Mimics software was accurate and reliable in linear calculation. Three-dimensional costal cartilage imaging was found to be an efficient tool for morphological evaluation of costal cartilages. We believe that with the application of individualised cartilage models based on three-dimensional printing, the use of customised ear framework carving will be practicable in surgical training.

Three-dimensional Volumetric Analysis of 3 Fat-Processing Techniques for Facial Fat Grafting: A Randomized Clinical Trial

Importance

Autologous fat grafting has revolutionized the field of facial soft-tissue augmentation, despite a lack of standardization. Objective data are needed to arrive at consensus regarding the best technique for optimal volume retention.

Objective

To compare 3 fat-processing techniques with 3-dimensional (3-D) technology to explore the optimal fat-processing technique for improving the volume retention of grafted fat.

Design, Setting, and Participants

From September 2015 to December 2016, patients with facial asymmetry were treated by initial facial fat grafting at the Plastic Surgery Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College. Sixty-three patients (21 per group) were randomized to 1 of 3 fat-processing techniques: sedimentation, centrifugation, and cotton pad filtration. Patients underwent 3-D scanning preoperatively and at 1, 3, 6, and 12 months postoperatively. Patients who did not complete preoperative or postoperative follow-up and 3-D imaging were excluded from the analysis.

Intervention

Autologous fat grafting to correct facial asymmetry.

Main Outcomes and Measures

The percentage volume maintenance of each fat-processing technique was measured with 3-D software and analyzed with variance analysis.

Results

Of the 63 randomized patients, 30 (7 men, 23 women; mean [SD] age at surgery, 22.2 [8.0] years) completed follow-up. The mean (SD) percentage volume maintenance of the 3 groups at 1, 3, 6, and 12 months postoperatively was, respectively, 49% (4%), 45% (3%), 43% (3%), and 41% (3%) for the cotton pad filtration group; 41% (3%), 38% (4%), 36% (4%), and 34% (3%) for the centrifugation group; and 37% (4%), 34% (4%), 31% (3%), and 31% (3%) for sedimentation group. The variance analysis showed that the cotton pad filtration group demonstrated a statistically significant higher percentage volume maintenance in comparison with the centrifugation and sedimentation groups.

Conclusions and Relevance

The use of 3-D technology provides an objective and accurate way to evaluate different fat-processing techniques. Autologous fat processed by cotton pad filtration had a significant higher volume retention than did that processed by centrifugation and sedimentation technique.

Trial Registration

chictr.org.cn Identifier: ChiCTR-IOR-14005599.

Level of Evidence

1.

[Application of three-dimensional mechanical equilibrium concept in cartilage scaffold construction for total auricular reconstruction]

Objective

To summarize clinical experience and curative effect in applying three-dimensional mechanical equilibrium concept to cartilage scaffold construction in total auricular reconstruction.

Methods

Between June 2015 and June 2017, ninety-seven microtia patients (102 ears) were treated with total ear reconstruction by using tissue expanders. The patients included 43 males and 54 females and their age ranged from 7 to 45 years with an average of 14 years. There were 92 unilateral cases (45 in left side and 47 in right side) and 5 bilateral ones. There were 89 congenital cases and 8 secondary cases. According to microtia classification criteria, there were 21 cases of type Ⅱ, 67 cases of type Ⅲ, and 9 cases of type Ⅳ. Tissue expander was implanted in the first stage. In the second stage, autogenous cartilage was used to construct scaffolds which were covered by enlarged flap. According to the three-dimensional mechanical equilibrium concept, the stable ear scaffold was supported by the scaffolds base, the junction of helix and inferior crura of antihelix, and helix rim. The reconstructed ears were repaired in the third stage operation.

Results

All patients had undergone ear reconstruction successfully and all incisions healed well. No infection, subcutaneous effusion, or hemorrhage occurred after operation. All skin flaps, grafts, and ear scaffolds survived completely. All patients received 5- to 17-month follow-up time (mean, 11.3 months) and follow-up time was more than 12 months in 61 cases (64 ears). All reconstructed ears stood upright, and subunits structure and sensory localization of reconstructed ears were clear, and the position, shape, size, and height of bilateral ears were basically symmetrical. Mastoid region scar hyperplasia occurred in 3 patients, which was relieved by anti-scar drugs injection. No scaffolds exposure, absorption, or structural deformation occurred during follow-up period.

Conclusion

Application of three-dimensional mechanical equilibrium concept in cartilage scaffold construction can reduce the dosage of costal cartilage, obtain more stable scaffold, and acquire better aesthetic outcomes.

Descriptive Analysis of the Arterial Supply to the Auricle in Patients with Unilateral Microtia

Background:

Microtia is a congenital auricular deformity that occurs in 1:5,000–10,000 births. It can cause severe impairment to the patient’s self-esteem and problems regarding social integration. Multiple measures have been described in attempt to better operative outcomes of these patients. We used computed tomography (CT) angiography to analyze the vascular pattern of the auricular region before surgery.

Methods:

Fourteen patients with unilateral microtia were included. All underwent CT angiogram plus tridimensional reconstruction. Both healthy and microtic auricles were analyzed descriptively in terms of main arterial supply, pattern, diameter of subbranches, and angulation. The sample was divided in 2 age groups for better understanding of the data.

Results:

Blood supply to the auricle was found to depend on 2 main vessels: temporal superficial artery (TSA) and its subbranches (superior, middle, and lower branch) and posterior auricular (PA) artery. In the microtic group, TSA was the dominant artery in 13 of 14 cases (92%). Superior, middle, and inferior branches were present in 4, 3, and 0 cases, respectively. Three of the microtic auricles presented supply from PA artery, from which in 1 case, it represented the only supply to the region.

Conclusions:

There is wide variability in the blood supply of both healthy and microtic auricles; however, we were able to identify some tendencies in our sample. Further research is needed to prove the benefit of a preoperative imaging study in these patients. Still, in our experience, we found it useful as a complement for surgical planning.

Microtia Reconstruction

Microtia reconstruction is a challenging endeavor that has seen significant technique evolution. It is important to educate patients and their families to determine the best hearing rehabilitation and ear reconstructive options. Microtia is often associated with aural atresia, hearing loss, and craniofacial syndromes. Optimal care is provided by multiple disciplines, including a reconstructive surgeon, an otologic surgeon, an audiologist, and a craniofacial pediatrician. Microtia management includes observation, prosthetic ear, autologous cartilage reconstruction, or alloplastic implant placement. Hearing management options are observation, bone conduction sound processor, or atresiaplasty with and without hearing aids. Appropriate counseling should be done to manage expectations.

Sternal Development and Variations and Anomalies in Patients With Microtia: Evaluation Using 3-Dimensional Computed Tomography

OBJECTIVE

The objectives of this study were to evaluate sternal development and variations in patients with microtia and to identify the incidence of congenital sternal anomalies and then to investigate the interaction between microtia and sternal anomalies.

METHODS

A total of 212 consecutive patients received a preoperative 3-dimensional chest computed tomography. A retrospective study was performed with the clinical and imaging data from November 2014 to July 2015. Descriptive statistics, analysis of variance, Spearman analysis, χ test, and Fisher χ test were performed for statistics analysis.

RESULTS

We evaluated the ossification centers and developmental variations in the manubrium and body, as well as the xiphoid process, manubriosternal and sternoxiphoidal fusion, and sternal anomalies. Significant variations were observed from person to person. Sternal foramen was detected in 6 male patients (2.8%). All foramina were located in the inferior part of the body. Sternal cleft was observed in 4 cases (1.9%), of which 2 were accompanied by a foramen in the distal part of the sternum.

CONCLUSIONS

The development of the different components of the sternum is a process with wide variation among patients with microtia. A different distribution of mesosternal types I to II among our population age range was found, and the incidence of sternal foramina was lower in patients with microtia.