Microtia Reconstruction

Integrated biomimetic bioprinting of perichondrium with cartilage for auricle reconstruction

The construction and regeneration of tissue-engineered auricles are pacesetters in tissue engineering and have realized their first international clinical application. However, the unstable regeneration quality and insufficient mechanical strength have become significant obstacles impeding its clinical promotion. The perichondrium is indispensable for the nutritional and vascular supply of the underlying cartilage tissue, as well as for proper anatomical functioning and mechanical performance. This study presents a novel strategy for integrated construction of bioengineered perichondrium with bioprinted cartilage to enhance the regeneration quality and mechanical properties of tissue-engineered auricles. Simulating the anatomical structure of the native auricle designs a sandwich construction model containing bilateral perichondrium and intermediate cartilage, employing a photocrosslinkable acellular cartilage matrix and gelatin bionics matrix microenvironment, applying co-cultured auricular chondrocytes and adipose-derived stem cells creates functional cell populations, designing hatch patterns imitates microscopic arrangement structures, utilizing sacrificial materials forms interlaminar network traffic to enhance the tight connection between layers, and finally, assessing the regenerative quality of the constructs explores their feasibility and stability. The multi-level and multi-scale biomimetic construction strategy overcomes the technical limitation of the integrated construction of perichondrium-wrapped auricles and realizes biomimicry in morphology, structure, and biomechanics. Altogether, this study provides a technical reference for the hierarchical construction of complex tissues and promotes the clinical translation and application of engineered tissues or organs.

Socioeconomic disparities in reconstructive pediatric microtia surgery

OBJECTIVE

To assess the association of race/ethnicity and education status on time to intervention and the total number of interventions in pediatric patients with microtia undergoing hearing intervention and external ear reconstruction.

METHODS

A retrospective chart review was performed in pediatric patients diagnosed with congenital ear deformities evaluated by an otolaryngologist or audiologist from January 1, 2013 to December 1, 2021 at a large surgical institution. Variables analyzed included demographics, patient conditions, time to surgery, and number of surgeries. Statistical analysis included analysis of variance, chi-squared tests, and multivariate regression.

RESULTS

Disparities were identified in reconstructive microtia repair, with non-White patients having an increased number of external ear reconstructive surgeries (p = 0.004), with Black patients average 2 external ear reconstructive surgeries, Hispanic patients 1.74 surgeries, while White patients averaged 0.812 surgeries. All non-White patients also demonstrated increased total number of surgeries (1.94 Asian, 2.57 Black, 2.11 Hispanic, 3.29 Other/Unknown, vs 1.23 White, p = 0.007) and total number of interventions (2.17 Asian, 2.71 Black, 2.37 Hispanic 3.43 Other/Unknown, vs 1.56 White, p = 0.02) as compared to White patients. In multivariate regression analysis, race was a significant factor influencing the number of reconstructive and overall surgeries, while the presence of aural atresia was the strongest predictor for requiring additional hearing surgery.

CONCLUSION

An increased number of interventions and surgeries were seen amongst non-White patients with microtia. Further investigation is warranted to understand the socioeconomic factors associated with pediatric microtia surgery.

Reconstructive Techniques in Pediatric Congenital Microtia: A Systematic Review and Meta-analysis

Autografts and allografts are commonly used in microtia reconstruction. We aimed to systematically review and compare these reconstructive materials in pediatric congenital microtia reconstruction. A systematic review of the literature was performed. MEDLINE, Embase, PubMed, Web of Science, and CINAHL databases were searched for original studies on congenital microtia reconstruction in pediatric patients since database inception to 2021. Microtia grade was stratified as high or low. Meta-analysis of pooled proportions and continuous variables was performed using inverse variance weighting with a random effects model to compare between the autograft and allograft groups. Sixty-eight studies with a total of 5,546 patients used autografts (n = 5,382) or alloplastic implants (n = 164). Four other studies used prosthesis, cadaveric homografts, or tissue engineering. The allograft group was on average younger than the autograft group (8.4 vs. 11.1 years). There were no syndromic patients in the allograft group, compared to 43% in the autograft group. Patients treated with allografts had higher microtia grade than those treated with autograft (98 vs. 72%). Autografts were more commonly utilized by plastic surgeons and allografts by otolaryngologists (95 vs. 38%). No autografts and 41% of allografts were done concurrently with atresiaplasty or bone conduction implant. Satisfaction rates were similarly high (>90%) with similar complication rates (<10%). Microtia reconstruction using autografts and allografts had similar satisfaction and complication rates. Allografts were preferred for younger patients and concurrent hearing restoration. Further large-scale studies are required to evaluate the long-term efficacy of these reconstructive techniques.

Microtia: A Review

Microtia is a congenital condition characterized by a spectrum of ear malformations, ranging from minor structural anomalies to anotia. The etiology is multifactorial, with interplay of genetic and environmental factors being implicated. Early multidisciplinary involvement should include pediatrics, plastic surgery, otolaryngology, audiology, and speech pathology, to ensure that the child is appropriately supported as they grow. This article provides an overview of the condition, a brief historic review, and illustrated descriptions of 2 common surgical approaches: porous polyethylene reconstruction with a temporoparietal fascia flap, and autologous reconstruction in 2 stages following Firmin's modifications of the Nagata technique.

The application of multilayered three-dimensional costal cartilage framework in auricular reconstruction with expanded postauricular skin flap

BACKGROUND

This study introduces a construction method for a multilayered three-dimensional costal cartilage auricular framework and retrospectively analyzed its clinical effectiveness in auricular reconstruction with an expanded postauricular skin flap.

METHODS

We designed multiple techniques for constructing a multilayered three-dimensional costal cartilage auricular framework to enhance stability and aesthetic outcomes. Postoperative follow-up included a comprehensive morphological assessment of the reconstructed ears, as well as evaluations of postoperative complications and patient satisfaction.

RESULTS

The study collected data on 75 patients who underwent auricular reconstruction in our department between January 2021 and December 2022, totaling 81 ears. During the follow-up period of 1 to 2 years postoperatively, plastic surgeons conducted a comprehensive morphological assessment of the reconstructed ears. Of these, 64 ears (79.0%) were rated as having good morphology, 13 ears (16.0%) as moderate, and 4 ears (4.9%) as poor. A survey on patient satisfaction revealed that 62 patients (82.7%) were satisfied with their reconstructed ears, 11 patients (14.7%) found the results acceptable, and 2 patients (2.7%) deemed them unacceptable. Postoperative complications included infections in 2 ears (2.5%), hematoma in 1 ear (1.2%), cartilage framework exposure in 3 ears (3.7%), and hypertrophic scarring in 5 ears (6.2%). There were no instances of skin flap necrosis, frame deformation, absorption, or wire exposure during the follow-up period.

CONCLUSIONS

The multilayered three-dimensional costal cartilage auricular framework we constructed for auricular reconstruction with an expanded postauricular skin flap resulted in the majority of reconstructed ears maintaining a satisfactory shape, with clear substructures, lifelike morphology, and strong three-dimensionality. Patient satisfaction with the surgical outcomes was high, achieving good stability and aesthetic effects.

Superficial temporal artery branching pattern in single stage auricular reconstruction: A novel classification

INTRODUCTION

The two most severe complications of single-stage, porous polyethene microtia reconstruction are flap necrosis/framework exposure and frontal nerve paralysis. To reduce these risks, require a temporoparietal fascia (TPF) flap that includes both the parietal and frontal branches of the superficial temporal artery (STA) while sparing the nerve. We propose a classification that helps minimize said complications.

MATERIAL AND METHODS

Fifty-five TPF flaps of 54 microtia patients who underwent single-stage auricular reconstruction from May 2018 to July 2021 were studied. Flaps were harvested using endoscopic techniques. The parietal and frontal branch characteristics and measurements were obtained using a microscope/endoscope.

RESULTS

The frontal artery might have 1 to 4 branches. If they were close to Pitanguy's line (≤5 mm), there would be a high risk of nerve damage. Parietal (P) and frontal (F) artery diameters <0.5 mm were risk factors for partial flap necrosis. Based on this observation, we proposed 0.5 mm as the diameter threshold to determine whether an arterial branch is hypoplasia or sufficient. From this study, a new classification of STA branching pattern was proposed with five types: PF1 (23.6 %), PF2 (43.6 %), pF1 (3.6 %), pF2 (12.8 %), and Pf (16.4 %); where P/F indicates sufficient branches, p/f indicates absent or hypoplasia ones, and the number indicates single or multiple frontal artery branching.

CONCLUSION

The risk of flap necrosis and frontal nerve damage is due to abnormalities of the frontal artery of the STA in the TPF flap. Understanding the anatomical classification with clear visualization during flap harvest ensures a successful outcome.

Improvement of Quality of Life After Microtia Reconstruction Using a Modified Firmin Technique-Case Series of 130 Patients

BACKGROUND

Microtia usually presents as a unilateral defect often associated with hearing impairment and significant psychosocial challenges. Reconstruction with autologous rib cartilage is currently the gold standard due to lower complication rates. However, outcomes remain variable.

AIMS AND OBJECTIVES

This study aims to assess the outcomes of a modified two-stage surgery technique, focusing on complications, aesthetics, satisfaction, and quality of life.

MATERIALS AND METHODS

A retrospective review of 130 patients undergoing ear reconstruction from 2016 to 2022 was conducted. Data included defect etiology, classification, and complications. Quality of Life was assessed using an adaptation of the questionnaire proposed by UK Care Standards for the Management of Patients with Microtia and Atresia.

RESULTS

Most patients had congenital microtia (78%), with type III being the most common (81%). The majority were male (73%), with a mean age of 21 years. Surgeon-assessed outcomes were good in 90% of cases. The most common complication was partial skin necrosis (13%). Among 73 respondents (answer rate of 56%), there was a significant improvement in quality of life post-reconstruction (p = 2.4e-12).

CONCLUSION

Modifications to Firmin's technique, such as smaller thoracic incisions, limited dissection, and specific flap designs, enhanced aesthetic results while reducing complications. In conclusion, our modified technique offers improved outcomes in microtia reconstruction, emphasizing the importance of technical refinements in achieving satisfactory results and enhancing patient well-being.

LEVEL OF EVIDENCE IV

This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors  www.springer.com/00266 .

Exploring mismatch negativity in children with congenital Microtia-Atresia: A Preliminary study

BACKGROUND

To investigate the characteristics of mismatch negativity (MMN) in terms of latency and amplitude in children with bilateral congenital microtia using a Bone conduction implant (Bonebridge), and to explore the relationship between cortical level auditory discrimination, speech perception, and psychosocial well-being.

METHODS

This descriptive, observational, cross-sectional study compared three groups: eight children with bilateral congenital microtia and Bonebridge implants (bilateral group), eight children with unilateral congenital microtia and no hearing aids (unilateral group), and eight children with normal hearing (NH group). Participants underwent MMN evaluation using a classic oddball paradigm with a pure tone burst stimulus, featuring a 1000 Hz standard stimulus and a 1200 Hz deviant stimulus, presented in a sound field at 65 dBHL. Additionally, speech perception tests, the Meaningful Use of Speech Scale (MUSS), and psychosocial status questionnaires, including the Social Anxiety Scale for Children (SASC) and the Children's Loneliness Scale (CLS), were administered to all subjects.

RESULTS

The bilateral group's average MMN latency was 241.23 ± 29.47 ms, and the unilateral group's was 209.96 ± 54.32 ms, both significantly longer than the NH group's 146.05 ± 15.73 ms (p < 0.0001, F=3.509, 95 % CI 68.09 to 122.3 and p = 0.0097, F=11.92, 95 % CI 18.07 to 109.8, respectively). However, no significant difference was found in MMN latency between the bilateral and unilateral groups (p = 0.202, F=3.397, 95 % CI -18.84 to 81.36). The unilateral group scored significantly higher on the MUSS (38.63 ± 1.41 vs. 30.75 ± 3.80, p = 0.0001, F=7.276, 95 % CI -11.16 to -4.590), had lower CLS scores (47.13 ± 8.13 vs. 58.25 ± 8.39, p = 0.024, F=1.065, 95 % CI 1.652 to 20.60), and lower SASC scores (4.13 ± 2.09 vs. 6.50 ± 2.25, p = 0.062, F=1.204, 95 % CI -0.138 to 4.89) compared to the bilateral group. MMN latency in the bilateral group correlated with SASC scores.

CONCLUSION

The MMN latency in congenital microtia patients may serve as an indicator of central auditory discrimination capabilities. In children with bilateral congenital microtia and Bonebridge implants, MMN latency can reflect social anxiety conditions to a certain degree.

Predictors of 30-day complications, readmission, and postoperative length of stay in children undergoing autologous rib grafting for microtia

BACKGROUND

Predictors of outcomes in pediatric microtia surgery are not well understood within the current literature. A multi-institutional database study may reveal insights into these predictors.

OBJECTIVES

To explore the predictors of 30-day complications, 30-day readmission, and postoperative length of stay (PLOS) in pediatric microtia patients undergoing autologous rib grafting.

METHODS

The Pediatric National Surgical Quality Improvement Program was queried for details on patients with microtia (ICD-9/10 744.23/Q17.2) who underwent autologous rib grafting (CPT 21230) between 2012-2021. Demographics, comorbidities, inpatient status, 30-day complications, PLOS, and 30-day readmissions were analyzed. Statistical analyses were performed to compare the preoperative characteristics with postoperative outcomes.

RESULTS

Overall, 667 patients met the inclusion criteria. Sixty-three (9.4%) had at least one complication, and 19 (2.9%) were readmitted. Univariate analysis showed that inpatient status (p = 0.011) and race (p = 0.023) were associated with higher complication rates. Multivariate analysis revealed that outpatient status was associated with significantly lower odds of complications (OR: 0.49, 95% CI [0.27, 0.87], p = 0.018), and developmental delay was associated with higher odds of 30-day readmission (OR: 2.80, 95% CI [1.05, 7.17], p = 0.036). Longer operative time was associated with older age (13.9% increase per five-year age increase, p < 0.001) and inpatient status (35.3% increase, p < 0.001). PLOS was shorter for outpatients (45.45% shorter, p < 0.001) and cases performed by plastic surgeons (14.2% shorter, p < 0.001).

CONCLUSION

Microtia reconstruction using autologous cartilage is a relatively safe procedure with low complication and readmission rates. Significant predictors of postoperative outcomes include inpatient status, race, developmental delay, and age. These findings highlight the importance of considering these factors in surgical planning and patient counseling.

Auricular deformity correction with simultaneous reconstruction of the conchal bowl using autologous ear cartilage for "flat ear": A novel surgical technique

BACKGROUNDS

"Flat ear" is a subtype of Grade II conchal-type microtia characterized by severely underdeveloped conchal bowl. Traditional surgical techniques often rely on autologous costal cartilage, which poses several risks and complications. This study aimed to introduce a novel surgical technique using autologous ear cartilage in auricular deformity correction surgery with simultaneous conchal bowl reconstruction for "flat ear."

METHODS

A total of 19 patients were involved in this single-center, retrospective cohort study. All patients underwent the described surgical technique. Data were collected preoperatively, immediately after the surgery, and at the last follow-up, including auricular length, width, perimeter, and conchal bowl depth. Patient satisfaction was assessed using the Visual Analog Scale (VAS).

RESULTS

The study included 12 males and 7 females, with an average age of 10.67 ± 3.86 years. Postoperative results showed significant improvements in auricular measurements, with the affected ear achieving near symmetry with the normal ear. The mean conchal bowl depth was restored from a preoperative 4.33 ± 1.78 mm to 17.32 ± 1.28 mm postoperatively. VAS scores for patient satisfaction increased significantly from 1.44 ± 0.92 preoperatively to 7.72 ± 1.49 postoperatively, with stability observed at the last follow-up.

CONCLUSION

The novel technique offers a promising alternative to traditional costal cartilage-based auricular deformity correction surgery, providing excellent aesthetic outcomes and high patient satisfaction. This approach may expand treatment options for patients with "flat ear" and related auricular deformities, with reduced invasiveness and potential for future auditory rehabilitation.

Auricular growth potential of patients with concha-type microtia after auricular cartilage stretching surgery: A prospective study

BACKGROUNDS

For patients with concha-type microtia, surgical intervention and the degree of deformity may affect the growth rate of the auricular cartilage, which is different at different ages. This study aimed to explore the auricular growth potential of patients with concha-type microtia at different ages after auricular cartilage stretching surgery.

METHODS

A total of 66 patients with unilateral grade II and III concha-type microtia were involved in this prospective cohort study. All patients underwent auricular cartilage stretching surgery. Relevant data were collected before surgery, immediately after surgery, and at the last follow-up.

RESULTS

The perimeter, width, and length of auricle, between each follow-up, was statistically significant, which supported the effect of surgery and auricular development. For patients in the grade II group, no statistical significance was found in the difference in the perimeter, width, and length between the affected and normal auricle. For the patients in the grade III group, the difference in the relevant indexes of the affected auricle was significantly different from those of the normal auricle. Between subgroups divided according to their age, the growth potential of affected auricle with the same degree of deformity was statistically significant.

CONCLUSIONS

Growth potential of the affected auricle of the grade II group was consistent with that of the normal auricle, which was significantly higher than that of the grade III group. For patients at different ages, auricles grew faster before 3 years of age. Surgical intervention improved the auricular aesthetics and released the auricular growth potential. Thus, surgical intervention should be recommend as early as possible.

Pharyngeal Arches, Chapter 2: Ear and Neck Abnormalities

The pharyngeal arches are the foundation of face and neck development. Impaired development of these embryologic structures can result in craniofacial abnormalities. Surgeons who manage head and neck pathology will invariably encounter conditions associated with aberrant pharyngeal arch anatomy, and a thorough understanding of the normal development of these structures is paramount to accurate diagnosis and treatment. This manuscript is the second of a four-part series written for plastic surgeons, focusing on the abnormal development of pharyngeal arches leading to pathologic ear and neck anomalies seen in clinical practice.

Hemifacial Microsomia Surgical Approach and Anotia Reconstruction: A Case Report

BACKGROUND/AIM

Hemifacial microsomia (HFM) is the second most common congenital anomaly of the craniomaxillofacial region after the cleft lip and palate. This malformation is characterized by unilateral mandible and ear hypoplasia. Treatment varies and depends on different phenotypes. Severe deficiencies require multiple reconstructive surgeries to address facial asymmetries. This study aimed to review the surgical approach and evaluate the postoperative results of a case with right hemifacial microsomia and anotia.

CASE REPORT

This is the case of a 35-year-old female patient who, after multiple graft operations in the right mandible due to hemifacial microsomia, was operated for auricle reconstruction. Initially, a three-dimensional custom made Medpor (porex) was used, covered by the superficial temporal fascia. Subsequently, due to inflammation and partial exposure of this porous polyethylene implant (PPI), a temporalis muscular flap along with the deep temporal fascia were used as a salvage operation. Ten months later, the patient underwent deep plane face lift combined with open rhinoplasty. Lefort I osteotomies and transoral lip lengthening through a transection of the levator nasi septi muscle were also performed. Ear helix reconstruction was completed with a rotation scalp flap after tissue expansion. The patient had an uncomplicated postoperative course with an aesthetically acceptable result.

CONCLUSION

As a congenital disorder, hemifacial microsomia is present at birth and successful reconstruction is of fundamental importance for the smooth integration of these individuals into society. The multiple asymmetries, the affected topographic area of the face, as well as the onset in neonatal age constitute a challenge for reconstructive surgery.

The utilization of three-dimensional imaging and three-dimensional-printed model in autologous microtia reconstruction

Background

The use of three-dimensional (3D) technology helps surgeons in performing autologous microtia reconstruction due to more accurate measurements and a better precision template model. However, the technical aspects of using a 3D imaging and 3D-printed model and the difference in outcomes postoperatively remain poorly reviewed.

Purpose

This systematic review aimed to provide the current evidence of the benefit and technical aspects of using 3D technology in autologous microtia reconstruction.

Method

A systematic literature search was conducted across multiple databases: Medline, Embase, Google Scholar, and Central until June 2022. Studies that evaluated the use of 3D imaging or 3D-printed models for autogenous microtia reconstruction were selected. The quality of the included studies was also assessed with respect to the study design.

Result

A systematic literature search yielded 17 articles with a combination of observational and case report studies. Overall, 3D imaging showed a precise measurement for preoperative costal cartilage assessment. Compared to the 2D template, the utilization of a 3D-printed template provided a higher similarity rate relative to the unaffected ear, higher patient and surgeon satisfaction, and lower surgical time. Most 3D templates were fabricated using polylactic acid material on fused deposition modelling printers. The template costs were ranging from $1 to $4.5 depending on the material used.

Conclusion

3D imaging and 3D-printed templates could improve the outcome of autologous microtia reconstruction. However, the quality of the existing evidence remains low due to the heterogeneity of the reported outcomes. Further studies with more adequate comparability and defined outcomes are still required.

Bioengineering Full-scale auricles using 3D-printed external scaffolds and decellularized cartilage xenograft

Reconstruction of the human auricle remains a formidable challenge for plastic surgeons. Autologous costal cartilage grafts and alloplastic implants are technically challenging, and aesthetic and/or tactile outcomes are frequently suboptimal. Using a small animal "bioreactor", we have bioengineered full-scale ears utilizing decellularized cartilage xenograft placed within a 3D-printed external auricular scaffold that mimics the size, shape, and biomechanical properties of the native human auricle. The full-scale polylactic acid ear scaffolds were 3D-printed based upon data acquired from 3D photogrammetry of an adult ear. Ovine costal cartilage was processed either through mincing (1 mm3) or zesting (< 0.5 mm3), and then fully decellularized and sterilized. At explantation, both the minced and zested neoears maintained the size and contour complexities of the scaffold topography with steady tissue ingrowth through 6 months in vivo. A mild inflammatory infiltrate at 3 months was replaced by homogenous fibrovascular tissue ingrowth enveloping individual cartilage pieces at 6 months. All ear constructs were pliable, and the elasticity was confirmed by biomechanical analysis. Longer-term studies of the neoears with faster degrading biomaterials will be warranted for future clinical application. STATEMENT OF SIGNIFICANCE: Accurate reconstruction of the human auricle has always been a formidable challenge to plastic surgeons. In this article, we have bioengineered full-scale ears utilizing decellularized cartilage xenograft placed within a 3D-printed external auricular scaffold that mimic the size, shape, and biomechanical properties of the native human auricle. Longer-term studies of the neoears with faster degrading biomaterials will be warranted for future clinical application.

The circular RNA expression profile of human auricle cartilage and the role of circCOL1A2 in isolated microtia

Microtia is one of the most common craniofacial birth defects worldwide, and its primary clinical manifestation is auricle deformity. Epigenetic factors are known to contribute to the etiology of microtia, yet the involvement of circular RNAs (circRNAs) in human auricle development and their association with microtia remains poorly understood. In this study, we aimed to analyze differentially expressed circRNAs and explore their functional implications in isolated microtia. By employing circRNA microarray analysis and bioinformatics approaches, we identified 340 differentially expressed circRNAs in auricle cartilage of patients with isolated microtia, comprising 152 upregulated and 188 downregulated circRNAs. A circRNA-mRNA co-expression network was constructed, followed by gene ontology analysis and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analysis. Subsequently, we selected four significantly upregulated circRNAs from the co-expression network based on their association with cartilage development and validated their expressions in 30 isolated microtia and 30 control clinical auricle cartilage samples. Among these circRNAs, circCOL1A2, the most significantly upregulated circRNA, was selected as a representative circRNA for investigating its role in isolated microtia. Overexpression of circCOL1A2 significantly inhibited chondrocyte proliferation and chondrogenic differentiation of human mesenchymal stem cells. Additionally, circCOL1A2 upregulated Dermatan Sulfate Epimerase Like (DSEL) expression by sponging miR-637 through the competing endogenous RNA (ceRNA) mechanism. Notably, the downregulation of DSEL attenuated the inhibitory effect of circCOL1A2 overexpression on cell proliferation and chondrogenic differentiation. Collectively, these findings highlight the involvement of circCOL1A2 in the pathogenesis of isolated microtia and emphasize the potential significance of dysregulated circRNAs in disease development.

Current Status of Auricular Reconstruction Strategy Development

Microtia has severe physical and psychological impacts on patients, and auricular reconstruction offers improved esthetics and function, alleviating psychological issues. Microtia is a congenital disease caused by a multifactorial interaction of environmental and genetic factors, with complex clinical manifestations. Classification assessment aids in determining treatment strategies. Auricular reconstruction is the primary treatment for severe microtia, focusing on the selection of auricular scaffold materials, the construction of auricular morphology, and skin and soft tissue scaffold coverage. Autologous rib cartilage and synthetic materials are both used as scaffold materials for auricular reconstruction, each with advantages and disadvantages. Methods for achieving skin and soft tissue scaffold coverage have been developed to include nonexpansion and expansion techniques. In recent years, the application of digital auxiliary technology such as finite element analysis has helped optimize surgical outcomes and reduce complications. Tissue-engineered cartilage scaffolds and 3-dimensional bioprinting technology have rapidly advanced in the field of ear reconstruction. This article discusses the prevalence and classification of microtia, the selection of auricular scaffolds, the evolution of surgical methods, and the current applications of digital auxiliary technology in ear reconstruction, with the aim of providing clinical physicians with a reference for individualized ear reconstruction surgery. The focus of this work is on the current applications and challenges of tissue engineering and 3-dimensional bioprinting technology in the field of ear reconstruction, as well as future prospects.

Seminars in Plastic Surgery: Pediatric Ear Anomalies and Reconstruction

Congenital ear anomalies affect 15 to 20% of neonates and can be categorized as either auricular deformations or malformations. Deformations involve a fully developed, albeit abnormally shaped, chondrocutaneous framework, which makes them amenable to correction with ear molding within the first few months of life. Malformations involve hypoplastic or fully absent auricular structures that require augmentation with alloplastic and/or autogenous reconstruction. The goal of this article is to outline the various auricular deformities and malformations, followed by a description of the latest clinical management options, both nonsurgical and surgical, by auricular anomaly.

Combining bioengineered human skin with bioprinted cartilage for ear reconstruction

Microtia is a congenital disorder that manifests as a malformation of the external ear leading to psychosocial problems in affected children. Here, we present a tissue-engineered treatment approach based on a bioprinted autologous auricular cartilage construct (EarCartilage) combined with a bioengineered human pigmented and prevascularized dermo-epidermal skin substitute (EarSkin) tested in immunocompromised rats. We confirmed that human-engineered blood capillaries of EarSkin connected to the recipient's vasculature within 1 week, enabling rapid blood perfusion and epidermal maturation. Bioengineered EarSkin displayed a stratified epidermis containing mature keratinocytes and melanocytes. The latter resided within the basal layer of the epidermis and efficiently restored the skin color. Further, in vivo tests demonstrated favorable mechanical stability of EarCartilage along with enhanced extracellular matrix deposition. In conclusion, EarCartilage combined with EarSkin represents a novel approach for the treatment of microtia with the potential to circumvent existing limitations and improve the aesthetic outcome of microtia reconstruction.

National Trends in Microtia Repair Cost and Hospital Length of Stay

Microtia can have deleterious impacts on the functional, psychological, and aesthetic outcomes of affected young children. Reconstructive procedures can alleviate these negative outcomes and significantly improve the quality of life for patients; however, the cost and length of hospital stay (LOS) for such procedures and the factors that impact them have not been well-characterized. This study seeks to understand the hospital-level (institution type, size, and geographic region) and patient-level factors (race, age, and insurance status) that impact cost and LOS in patients who undergo microtia reconstructive surgery. A retrospective data analysis was conducted utilizing the National Inpatient Sample (NIS) database for the years 2008 to 2015. Inclusion criteria included patients who had an International Classification of Diseases, Ninth Revision (ICD-9) diagnostic code for microtia (744.23) as well as a procedure for microtia correction (186×/187×). A total of 714 microtia repair cases met the inclusion criteria and were sampled from the NIS database. Microtia repair cost was significantly increased on the West Coast compared with the Northeast ($34,947 versus $29,222, P =0.020), increased with patient age ($614/y, P =0.012), and gradually increased from 2008 to 2015 ($25,897-$48,985, P <0.001). Microtia LOS was significantly increased with government-controlled hospitals compared with private hospitals (1.93 versus 1.39 d, P =0.005), increased with patients on Medicaid compared with private insurance (2.33 versus 2.00 d, P =0.036), and overall decreased with patient age (-0.07 d/y, P =0.001). The results not only identify the multifactorial impacts that drive cost and LOS in microtia repair but provide insights into the financial and medical considerations patients and their families must navigate.

The application and progress of tissue engineering and biomaterial scaffolds for total auricular reconstruction in microtia

Microtia is a congenital deformity of the ear with an incidence of about 0.8-4.2 per 10,000 births. Total auricular reconstruction is the preferred treatment of microtia at present, and one of the core technologies is the preparation of cartilage scaffolds. Autologous costal cartilage is recognized as the best material source for constructing scaffold platforms. However, costal cartilage harvest can lead to donor-site injuries such as pneumothorax, postoperative pain, chest wall scar and deformity. Therefore, with the need of alternative to autologous cartilage, in vitro and in vivo studies of biomaterial scaffolds and cartilage tissue engineering have gradually become novel research hot points in auricular reconstruction research. Tissue-engineered cartilage possesses obvious advantages including non-rejection, minimally invasive or non-invasive, the potential of large-scale production to ensure sufficient donors and controllable morphology. Exploration and advancements of tissue-engineered cartilaginous framework are also emerging in aspects including three-dimensional biomaterial scaffolds, acquisition of seed cells and chondrocytes, 3D printing techniques, inducing factors for chondrogenesis and so on, which has greatly promoted the research process of biomaterial substitute. This review discussed the development, current application and research progress of cartilage tissue engineering in auricular reconstruction, particularly the usage and creation of biomaterial scaffolds. The development and selection of various types of seed cells and inducing factors to stimulate chondrogenic differentiation in auricular cartilage were also highlighted. There are still confronted challenges before the clinical application becomes widely available for patients, and its long-term effect remains to be evaluated. We hope to provide guidance for future research directions of biomaterials as an alternative to autologous cartilage in ear reconstruction, and finally benefit the transformation and clinical application of cartilage tissue engineering and biomaterials in microtia treatment.

Characterization of Distinct Chondrogenic Cell Populations of Patients Suffering from Microtia Using Single-Cell Micro-Raman Spectroscopy

Microtia is a congenital condition of abnormal development of the outer ear. Tissue engineering of the ear is an alternative treatment option for microtia patients. However, for this approach, the identification of high regenerative cartilage progenitor cells is of vital importance. Raman analysis provides a novel, non-invasive, label-free diagnostic tool to detect distinctive biochemical features of single cells or tissues. Using micro-Raman spectroscopy, we were able to distinguish and characterize the particular molecular fingerprints of differentiated chondrocytes and perichondrocytes and their respective progenitors isolated from healthy individuals and microtia patients. We found that microtia chondrocytes exhibited lower lipid concentrations in comparison to healthy cells, thus indicating the importance of fat storage. Moreover, we suggest that collagen is a useful biomarker for distinguishing between populations obtained from the cartilage and perichondrium because of the higher spectral contributions of collagen in the chondrocytes compared to perichondrocytes from healthy individuals and microtia patients. Our results represent a contribution to the identification of cell markers that may allow the selection of specific cell populations for cartilage tissue engineering. Moreover, the observed differences between microtia and healthy cells are essential for gaining better knowledge of the cause of microtia. It can be useful for designing novel treatment options based on further investigations of the discovered biochemical substrate alterations.

Ear reconstruction stage I: Minor modifications in sculpting the auricle support using the 7th and 8th costal cartilages

BACKGROUND

The verisimilitude of the reconstructed auricle and its long-term stability largely depends on the framework sculpting. This study described three kinds of minor modifications based on Firmin's way of sculpting the auricle framework and reported the clinical outcomes achieved with them.

METHODS

We conducted a retrospective study of congenital microtia patients undergoing detail-improved auricular reconstruction from June 2016 to June 2020. The three kinds of minor modifications included: (1) fabricating the base frame using the 7th costal cartilage, (2) fabricating the helix and the antihelix complex using the 8th costal cartilage, and (3) fabricating the helix using the combination of the 8th and 9th costal cartilage.

RESULTS

Ninety-eight patients (aged 9-27 years, 62.2% male) were included. Ninety-five patients (97.0%) adopted minor modifications 1, 2, and 3 patients (3.0%) adopted minor modifications 1, 2, and 3. All patients achieved an excellent auricle appearance and a well-laid foundation for subsequent operations. During the follow-up period, 89 patients (90.8%) were satisfied with the reconstructed auricles, 6 (6.1%) complained of hypertrophic scars in the retroauricular sulcus or pigmentation in the skin graft area, and 3 (3.1%) developed surgery-related complications.

CONCLUSIONS

Three minor modifications of the auricle framework sculpting can make more satisfactory use of cartilage and adjust with the flexibility of the reconstructed auricle in different situations, making it similar to the contralateral auricle, thus, improving patients' satisfaction.

Reconstruction of the external ear using implant-supported alloplasts-Our experience

Surgical reconstruction of the missing external ear is difficult, and the results are often far from satisfactory. An implant-retained auricular prosthesis is a suitable alternative. Microtia, malformation, deformity, and partial or complete loss of the external ear may be due to various congenital or acquired factors. A case series of three patients treated with implant-retained auricular prostheses is presented in this article. For each missing pinna, two titanium implants were placed in the temporal bone. After 6 months of osseointegration, the implants were loaded. All three cases were rehabilitated with a bar and clip retained prosthesis. There were two male and one female patient with an average age of 16.6 years. One patient had unilateral absence of external ear and two had bilateral absence. A total of 10 implants were placed, 4 on the right side and 6 on the left. The average post rehabilitation follow-up was 18 months. Peri-implant tissue reactions were observed at two sites. The implant-retained auricular prosthesis is an alternative treatment approach with good retention and patient satisfaction. Long-term follow-up is required to assess delayed sequelae.

The etiology, clinical features, and treatment options of hemifacial microsomia

The second most frequent craniomaxillofacial congenital deformity is hemifacial microsomia (HFM). Patients often accompany short mandible, ear dysplasia, facial nerve, and soft tissue dysplasia. The etiology of HFM is not fully understood. To organize the possible up-to-date information on the etiology, craniofacial phenotypes, and therapeutic alternatives in order to fully comprehend the HFM. Reviewing the potential causes, exploring the clinical features of HFM and summarizing the available treatment options. Vascular malformation, Meckel's cartilage abnormalities, and cranial neural crest cells (CNCCs) abnormalities are three potential etiology hypotheses. The commonly used clinical classification for HFM is OMENS, OMENS-plus, and SAT. Other craniofacial anomalies, like dental defects, and zygomatic deformities, are still not precisely documented in the classification. Patients with moderate phenotypes may not need any treatment from infancy through adulthood. However, patients with severe HFM require to undergo multiple surgeries to address facial asymmetries, such as mandibular distraction osteogenesis (MDO), autologous costochondral rib graft (CCG), orthodontic and orthognathic treatment, and facial soft tissue reconstruction. It is anticipated that etiology research will examine the pathogenic mechanism of HFM. A precise treatment for HFM may be possible with thoroughly documented phenotypes and a pathogenic diagnosis.

The Effect of Fixation Materials on the Long-Term Stability of Cartilage Framework for Microtia Reconstruction

Objective: To observe the effect of fixation materials on the long-term stability of the cartilage framework in auricular reconstruction. Methods: Consecutive patients who underwent the first stage of auricular reconstruction by the same surgical team from September 2018 to March 2021 were included. Those with braided absorbable suture, polypropylene suture, and titanium wire were defined as Groups A, B, and C, respectively. Six months later, when the patients underwent the second stage of surgery, absorption and deformation of the framework were assessed. Results: A total of 604 patients (622 ears) were included. The most common occurrence was spot absorption in the antihelix and was observed in 34.7%, 17.4%, and 22.8% ears in the A, B, and C groups, respectively (p < 0.05). There were also significant differences regarding severe absorption and severe deformation. The histological examination suggested that those in Group A had more T cells and macrophages around the suture than those in Groups B and C. Conclusion: Absorbable suture seems to correlate with higher risk of cartilage absorption and helix displacement. Titanium wire had the lowest rate of helix pop-out or fracture, which means the best stability.

Long-Term Clinical Results of Two-Stage Total Ear Reconstruction of Microtia Using Autologous Cell-Engineered Chondrocytes

BACKGROUND

Microtia repair requires a large volume of reconstruction material.In pediatric patients, the collectable volume of autologous cartilage is limited, and the impact of surgical invasion and donor-site morbidity can be particularly severe. The authors developed a new treatment method using cultured autologous human auricular chondrocytes that provides a sufficiently large volume of reconstruction material.

METHODS

Approximately 1 cm2 of auricular cartilage was collected from the affected site. Chondrocytes were isolated and cultured with autologous serum to accelerate cell proliferation. The cells were subcultured and formed a gel-form mass without a scaffold. In our two-stage implantation, the cultured chondrocytes were first injected into the patient's lower abdomen, where the cells grew into a large, newly generated cartilage in 6 months. Thereafter, this cartilage was sculpted into an ear framework and subcutaneously reimplanted into the new ear location. Clinical outcomes were assessed over a long-term follow-up.

RESULTS

Eight patients underwent surgery using cultured autologous auricular chondrocytes from 2002 to 2008. The patients' ages ranged from 6 to 10 years. The follow-up period ranged from 11 to 18 years. None of the patients experienced absorption of cultured chondrocytes after the second stage. Complications included one case of absorption and one case of allergic reaction in the first stage.

CONCLUSIONS

The authors' patients represent the first successful cases of regenerative surgery for microtia using cultured chondrocytes. No malignant transformation, change in size, deformation, or other abnormalities were observed during the long-term follow-up, demonstrating the safety of cultured cartilage. No major complications occurred.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, IV.

3D printed bionic ear and microtia-anotia: Medical and forensic implications

Advances in science and technology result in continuous upgrading of the medical and clinical fields. These upgrades have been beneficial to many patients suffering from congenital and developmental diseases causing compromised functionality as well as the structural integrity of the affected organs. One such congenital anomaly is the microtia-anotia spectrum, which results in deformities of the external ear, affecting the hearing capability of an individual. The collaboration and integration of electronics in human biology are exemplified by the development of a 3D printed cyborg bionic ear from the patient's own cells, which is implanted to ameliorate microtia and improve the patient's hearing capacity. Since the late nineteenth century, forensic scientists have explored the external ear, establishing the significance of ear biometrics in the identification process. Similarly, ear prints can also play an important role in identifying the felon of a crime. In this regard, we examine the structure and functionality of implanted ears. This communication is an attempt to enlighten investigators on the forensic importance and limitations of the use of bionic ears for identification.

Angular and Linear Accelerations, Ear, and the Skeletal Muscle

The ear serves two vital functions of hearing and maintaining balance. It achieves these roles within three major compartments: the outer, the middle, and the inner ear. Embryological development of the ear and its associated structures have been studied in some animal models. Yet, the role of skeletal muscle in ear development and its related structures is largely unknown. Research suggests the outer ear and parts of the inner ear may require skeletal muscle for normal embryogenesis. Here, we describe the role of skeletal muscle in the development of the ear and its associated structures. Moreover, we report the possible consequences of defect in the skeletal muscle of the ear and the clinical correlates of such consequences.

Factors associated with nonsyndromic anotia and microtia, Texas, 1999-2014

BACKGROUND

Few risk factors have been identified for nonsyndromic anotia/microtia (A/M).

METHODS

We obtained data on cases and a reference population of all livebirths in Texas for 1999-2014 from the Texas Birth Defects Registry (TBDR) and Texas vital records. We estimated prevalence ratios (PRs) and 95% confidence intervals (CIs) for A/M (any, isolated, nonisolated, unilateral, and bilateral) using Poisson regression. We evaluated trends in prevalence rates using Joinpoint regression.

RESULTS

We identified 1,322 cases, of whom 982 (74.3%) had isolated and 1,175 (88.9%) had unilateral A/M. Prevalence was increased among males (PR: 1.3, 95% CI: 1.2-1.4), offspring of women with less than high school education (PR: 1.3, 95% CI: 1.1-1.5), diabetes (PR: 2.0, 95% CI: 1.6-2.4), or age 30-39 versus 20-29 years (PR: 1.2, 95% CI: 1.0-1.3). The prevalence was decreased among offspring of non-Hispanic Black versus White women (PR: 0.6, 95% CI: 0.4-0.8) but increased among offspring of Hispanic women (PR: 2.9, 95% CI: 2.5-3.4) and non-Hispanic women of other races (PR: 1.7, 95% CI: 1.3-2.3). We observed similar results among cases with isolated and unilateral A/M. Sex disparities were not evident for nonisolated or bilateral phenotypes, nor did birth prevalence differ between offspring of non-Hispanic Black and non-Hispanic White women. Maternal diabetes was more strongly associated with nonisolated (PR: 4.5, 95% CI: 3.2-6.4) and bilateral A/M (PR: 5.0, 95% CI: 3.3-7.7). Crude prevalence rates increased throughout the study period (annual percent change: 1.82).

CONCLUSION

We identified differences in the prevalence of nonsyndromic A/M by maternal race/ethnicity, education, and age, which may be indicators of unidentified social/environmental risk factors.

In vitro elastic cartilage reconstruction using human auricular perichondrial chondroprogenitor cell-derived micro 3D spheroids

Morphologically stable scaffold-free elastic cartilage tissue is crucial for treating external ear abnormalities. However, establishing adequate mechanical strength is challenging, owing to the difficulty of achieving chondrogenic differentiation in vitro; thus, cartilage reconstruction is a complex task. Auricular perichondrial chondroprogenitor cells exhibit high proliferation potential and can be obtained with minimal invasion. Therefore, these cells are an ideal resource for elastic cartilage reconstruction. In this study, we aimed to develop a novel in vitro scaffold-free method for elastic cartilage reconstruction, using human auricular perichondrial chondroprogenitor cells. Inducing chondrogenesis by using microscopic spheroids similar to auricular hillocks significantly increased the chondrogenic potential. The size and elasticity of the tissue were maintained after craniofacial transplantation in immunodeficient mice, suggesting that the reconstructed tissue was morphologically stable. Our novel tissue reconstruction method may facilitate the development of future treatments for external ear abnormalities.

Development of an interdisciplinary microtia-atresia care model: A single-center 20-year experience

Objectives

Microtia and aural atresia are congenital ear anomalies with a wide-ranging spectrum of phenotypes and varied functional and psychosocial consequences for patients. This study seeks to analyze the management of microtia-atresia patients at our center over a 20-year period and to propose recommendations for advancing microtia-atresia care at a national level.

Methods

We performed a retrospective analysis of data from patients presenting to the Massachusetts Eye and Ear (Boston, MA) for initial otolaryngology consultation for congenital microtia and/or aural atresia between 1999 and 2018.

Results

Over the 20-year study period, 229 patients presented to our microtia-atresia center at a median age of 7 years. The severity of microtia was most commonly classified as grade III (n = 87, 38%), 61% (n = 140) of patients had complete atresia, the median Jahrsdoerfer grading scale score was 6 (range 0-10), and 81 patients (35%) underwent surgery for microtia repair. For hearing rehabilitation, 30 patients (64%) underwent bone conduction device implantation and 17 patients (36%) underwent atresiaplasty. The implementation of an interdisciplinary, longitudinal care model resulted in an increase in patient (r = 0.819, p < .001) and surgical volume (microtia surgeries, r = 0.521, p = .019; otologic surgeries, r = 0.767, p < .001) at our center over time.

Conclusion

An interdisciplinary team approach to microtia-atresia patient care may result in increased patient volume, which could improve aesthetic and hearing outcomes over time by concentrating care and surgical expertise. Future work should aim to establish standardized clinical consensus recommendations to guide the creation of high-quality microtia-atresia care programs.

Level of Evidence

4.

Porous biomaterials for tissue engineering: a review

The field of biomaterials has grown rapidly over the past decades. Within this field, porous biomaterials have played a remarkable role in: (i) enabling the manufacture of complex three-dimensional structures; (ii) recreating mechanical properties close to those of the host tissues; (iii) facilitating interconnected structures for the transport of macromolecules and cells; and (iv) behaving as biocompatible inserts, tailored to either interact or not with the host body. This review outlines a brief history of the development of biomaterials, before discussing current materials proposed for use as porous biomaterials and exploring the state-of-the-art in their manufacture. The wide clinical applications of these materials are extensively discussed, drawing on specific examples of how the porous features of such biomaterials impact their behaviours, as well as the advantages and challenges faced, for each class of the materials.

Contemporary management of microtia

Microtia techniques have evolved to improve aesthetic outcomes, reduce donor site morbidities, and reduce complications. Patients with microtia commonly have aural atresia associated with conductive hearing loss. We present the evolution of our technique for microtia reconstruction and considerations for hearing management in these patients. Keywords: Microtia, aural atresia, autologous rib reconstruction, contemporary management.

Bioprinting and regeneration of auricular cartilage using a bioactive bioink based on microporous photocrosslinkable acellular cartilage matrix

Tissue engineering provides a promising strategy for auricular reconstruction. Although the first international clinical breakthrough of tissue-engineered auricular reconstruction has been realized based on polymer scaffolds, this approach has not been recognized as a clinically available treatment because of its unsatisfactory clinical efficacy. This is mainly since reconstruction constructs easily cause inflammation and deformation. In this study, we present a novel strategy for the development of biological auricle equivalents with precise shapes, low immunogenicity, and excellent mechanics using auricular chondrocytes and a bioactive bioink based on biomimetic microporous methacrylate-modified acellular cartilage matrix (ACMMA) with the assistance of gelatin methacrylate (GelMA), poly(ethylene oxide) (PEO), and polycaprolactone (PCL) by integrating multi-nozzle bioprinting technology. Photocrosslinkable ACMMA is used to emulate the intricacy of the cartilage-specific microenvironment for active cellular behavior, while GelMA, PEO, and PCL are used to balance printability and physical properties for precise structural stability, form the microporous structure for unhindered nutrient exchange, and provide mechanical support for higher shape fidelity, respectively. Finally, mature auricular cartilage-like tissues with high morphological fidelity, excellent elasticity, abundant cartilage lacunae, and cartilage-specific ECM deposition are successfully regenerated in vivo, which provides new opportunities and novel strategies for the fabrication and regeneration of patient-specific auricular cartilage.

•

Comprehensive proteomic characteristics of the acellular cartilage matrix.

•

Bioactive bioink based on ACMMA, GelMA, and PEO promoted cell behavior.

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Bioactive bioink contained biomimetic ECM components and microporous structure.

•

Higher biomechanics was provided by alternately bioactive bioink and PCL strands.

•

Mature auricle cartilage with high shape fidelity and good mechanics was regenerated.

Oculo-auriculo-vertebral spectrum: new genes and literature review on a complex disease

Oculo-auriculo-vertebral spectrum (OAVS) or Goldenhar syndrome is due to an abnormal development of first and second branchial arches derivatives during embryogenesis and is characterised by hemifacial microsomia associated with auricular, ocular and vertebral malformations. The clinical and genetic heterogeneity of this spectrum with incomplete penetrance and variable expressivity, render its molecular diagnosis difficult. Only a few recurrent CNVs and genes have been identified as causatives in this complex disorder so far. Prenatal environmental causal factors have also been hypothesised. However, most of the patients remain without aetiology. In this review, we aim at updating clinical diagnostic criteria and describing genetic and non-genetic aetiologies, animal models as well as novel diagnostic tools and surgical management, in order to help and improve clinical care and genetic counselling of these patients and their families.

Patient-Reported Satisfaction After Autologous Auricular Reconstruction in Patients with Microtia: A Systematic Review

Importance: In a patient-centered field such as plastic surgery, patient-reported satisfaction can measure the success and value of surgery, since it is not uncommon for patient and surgeon assessments to differ. Currently, there is no standard for evaluating patient-reported satisfaction postauricular reconstruction. Objective: To systematically review the literature regarding patient-reported satisfaction postauricular reconstruction in microtia patients. Evidence Review: The databases MEDLINE, EMBASE, Cochrane, and Scopus were searched and preferred reporting items for systematic reviews and meta-analyses guidelines were followed. Studies documenting patient-reported satisfaction postauricular reconstruction in microtia patients were included. All techniques for ear reconstruction have been included in this review. Findings: Nineteen studies utilizing autologous reconstruction technique, comprising 3694 patients, met inclusion criteria. No standardized patient satisfaction assessment was used throughout the studies, indicating criteria variability to measure outcomes. Auricular substructure analysis highlighted lower patient satisfaction with the tragus and antitragus compared with the upper units. In addition, satisfaction depended on patient perception, not on a low surgical complication rate. Conclusions: There is a clear need to incorporate a standardized validated surgery-specific questionnaire related to patient satisfaction in the auricular reconstruction protocol.

Shape Optimization of Costal Cartilage Framework Fabrication Based on Finite Element Analysis for Reducing Incidence of Auricular Reconstruction Complications

Skin necrosis is the most common complication in total auricular reconstruction, which is mainly induced by vascular compromise and local stress concentration of the overlying skin. Previous studies generally emphasized the increase in the skin flap blood supply, while few reports considered the mechanical factors. However, skin injury is inevitable due to uneasily altered loads generated by the intraoperative continuous negative suction and uneven cartilage framework structure. Herein, this study aims to attain the stable design protocol of the ear cartilage framework to decrease mechanical damage and the incidence of skin necrosis. Finite element analysis was initially utilized to simulate the reconstructive process while the shape optimization technique was then adopted to optimize the three-pretested shape of the hollows inside the scapha and fossa triangularis under negative suction pressure. Finally, the optimal results would be output automatically to meet clinical requirement. Guided by the results of FE-based shape optimization, the optimum framework with the smallest holes inside the scapha and fossa triangularis was derived. Subsequent finite element analysis results also demonstrated the displacement and stress of the post-optimized model were declined 64.9 and 40.1%, respectively. The following clinical study was performed to reveal that this new design reported lower rates of skin necrosis decrease to 5.08%, as well as the cartilage disclosure decreased sharply from 14.2 to 3.39% compared to the conventional method. Both the biomechanical analysis and the clinical study confirmed that the novel design framework could effectively reduce the rates of skin necrosis, which shows important clinical significance for protecting against skin necrosis.

Management of patients with unilateral microtia and aural atresia: recent advances and updates

PURPOSE OF REVIEW

The management of patients with unilateral microtia and aural atresia is complex. Recent literature suggests significant strides in hearing habilitation and ear reconstruction.

RECENT FINDINGS

Several options of hearing management are available and are associated with improved outcomes. Timelines for hearing habilitation and ear reconstruction vary by institution. We offer our timeline as a reference. Three dimensional (3D) printed models are increasingly used for training and reconstruction. Bioprinting is on the horizon, though safety and effectiveness studies are pending. Lastly, application of qualitative methods has provided a foundation on which to improve communication between physicians and patients and their families. Better understanding of the patient and family experiences will provide opportunities to target interventions to improve care.

SUMMARY

Current developments include expanding options for hearing management, changing approaches to timing of atresiaplasty, utilization of 3D printed models, and focus on patient and family experience to improve reconstructive outcomes.

[Clinical analysis of congenital microtia complicated with retroauricular subperiosteal abscess in 7 cases]

Objective:To dissect the etiology and clinical features of congenital microtia with retroauricular subperiosteal abscess, and to explore its pathogenesis and prognosis. Methods:Among 178 patients with congenital microtia, 7 cases concomitant with " retroauricular subperiosteal abscess" were collected in this retrospective study . All of the 7 patients underwent mastoidotomy, the lesions were cleared, and secretions were sent to the bacterial culture test. According to the middle ear lesions, we performedopen mastoidectomy + tympanoplasty in 3 cases， wall mastoidectomy + tympanoplasty in 3 cases of andradical mastoidectomy in 1 case.The wound healing was observed subsequently， and the patients were followed up 3 months later. Results:The patients were mainly young. The average of air-bone gap before operation was （57.14±9.51） dB. The average ofair-bone gap after operation was （40.00±11.54） dB, which was lower than that before （17.14±11.12） dB. The operation can effectively control the flow of pus and improve hearing. Postoperative ear abscess was effectively controlled, and there is no recurrence, after half a year of follow-up. Conclusion:Early diagnosis of mastoiditis is of great significance for congenital microtia complicated with retroauricular subperiosteal abscess. It should be diagnosed and intervened as soon as possible. Once it develops into abscess, tympanoplasty should be performed as soon as possible, for cleaning lesions and draining obstruction, subsequently as to provide favorable conditions for the repair of auricular malformation.

Tissue Engineering the Pinna: Comparison and Characterization of Human Decellularized Auricular Biological Scaffolds

Decellularization is one of the promising techniques in tissue engineering used to create a biological scaffold for subsequent repopulation with the patient's own cells. This study aims to compare two different decellularization protocols to optimize the process of auricle decellularization by assessing and characterizing the decellularization effects on human auricular cartilage. Herein, 12 pairs (8 females, 4 males) of freshly frozen adult human cadaveric auricles were de-epithelialized and defatted leaving only the cartilaginous framework. An auricle from each pair was randomly assigned to either protocol A (latrunculin B-based decellularization) or protocol B (trypsin-based decellularization). Gross examination of the generated scaffolds demonstrated preservation of the auricles' contours and a change in color from pinkish-white to yellowish-white. Hematoxylin and eosin staining demonstrated empty cartilaginous lacunae in both study groups, which confirms the depletion of cells. However, there was greater preservation of the extracellular matrix in auricles decellularized with protocol A as compared to protocol B. Comparing protocol A to protocol B, Masson's trichrome and Safranin-O stains also demonstrated noticeable preservation of collagen and proteoglycans, respectively. Additionally, scanning electron micrographs demonstrated preservation of the cartilaginous microtopography in both study groups. Biomechanical testing demonstrated a substantial decrease in Young's modulus after decellularization using protocol B (1.3 MPa), albeit not significant (P-value > 0.05) when compared to Young's modulus prior to decellularization (2.6 MPa) or after decellularization with protocol A (2.7 MPa). A DNA quantification assay demonstrated a significant drop (P-value < 0.05) in the DNA content after decellularization with protocol A (111.0 ng/mg) and protocol B (127.6 ng/mg) in comparison to before decellularization (865.3 ng/mg). Overall, this study demonstrated effective decellularization of human auricular cartilage, and it is concluded that protocol A provided greater preservation of the extracellular matrix and biomechanical characteristics. These findings warrant proceeding with the assessment of inflammation and cell migration in a decellularized scaffold using an animal model.

Postoperative outcomes of autologous rib graft for microtia repair in children: A NSQIP study

OBJECTIVE

To compare the effect of surgical specialty and patient factors on 30-day postoperative outcomes and complications for children undergoing autologous costochondral grafting for microtia reconstruction.

METHODS

The American College of Surgeons National Surgical Quality Improvement Program Pediatric (NSQIP-P) database was searched from 2012 through 2017 for patients who underwent autologous rib grafting (CPT 21230). The group was further filtered for coexisting ICD 9 or 10 code for microtia (744.23, Q17.2) as an indication for surgery. Outcomes analyzed included patient demographics, medical comorbidities, admission type (inpatient vs. outpatient), operative time, surgeon specialty, length of hospital stay (LOS), complications, and readmission.

RESULTS

A total of 375 pediatric patients were identified of which 157 were female and 218 were male. Mean age at time of surgery was 9.6 years. Postoperative complications and readmission occurred in 5.6% and 3.5% of patients, respectively. Surgical site infection was the most common complication. Average operative time was 246.9 min. When comparing Otolaryngology to Plastic Surgery with multivariate analysis, there was no difference in admission type (OR 1.00, p = 0.993), complication rate (OR 0.91, p = 0.744), readmission (OR 0.68, p = 0.576), operative time (p = 0.471) or total LOS (p = 0.266).

CONCLUSION

The present study demonstrated postoperative complications and readmission rates following microtia repair as reported by the NSQIP-P database. Overall complication and readmission rates were low. No significant risk factors were identified on multivariate analysis. There were no differences between surgical specialty for complication rate, operative time, hospital stay or readmission when accounting for demographic data and comorbidities.

Craniofacial implants in a failed autologous reconstruction of microtia: a case report

Plastic surgical reconstruction is considered to be the gold standard for the repair of microtia as the results are permanent and constructed from the patient's own tissue; however, the multiple surgeries required and the difficulty in attaining adequate cosmetic results often result in patients choosing a prosthesis as a long-term rehabilitation. Advances in osseointegration in the craniofacial region have improved the outcomes with auricular prosthetics by providing a reliable method of attachment of the prosthesis and increasing patient acceptance. A case presentation illustrates the results of both treatment modalities and examines the outcomes on the same patient.

Fabrication of 3D Models for Microtia Reconstruction Using Smartphone-Based Technology

OBJECTIVE

Microtia reconstruction is technically challenging due to the intricate contours of the ear. It is common practice to use a two-dimensional tracing of the patient's normal ear as a template for the reconstruction of the affected side. Recent advances in three-dimensional (3D) surface scanning and printing have expanded the ability to create surgical models preoperatively. This study aims to describe a simple and affordable process to fabricate patient-specific 3D ear models for use in the operating room.

STUDY DESIGN

Applied basic research on a novel 3D optical scanning and fabrication pathway for microtia reconstruction.

SETTING

Tertiary care university hospital.

METHODS

Optical surface scanning of the patient's normal ear was completed using a smartphone with facial recognition capability. The Heges application used the phone's camera to capture the 3D image. The 3D model was digitally isolated and mirrored using the Meshmixer software and printed with a 3D printer (Monoprice^TM Select Mini V2) using polylactic acid filaments.

RESULTS

The 3D model of the ear served as a helpful intraoperative reference and an adjunct to the traditional 2D template. Collectively, time for imaging acquisition, editing, and fabrication was approximately 3.5 hours. The upfront cost was around $210, and the recurring cost was approximately $0.35 per ear model.

CONCLUSION

A novel, low-cost approach to fabricate customized 3D models of the ear is introduced. It is feasible to create individualized 3D models using currently available consumer technology. The low barrier to entry raises the possibility for clinicians to incorporate 3D printing into various clinical applications.

Immune-Inflammatory Responses of an Acellular Cartilage Matrix Biomimetic Scaffold in a Xenotransplantation Goat Model for Cartilage Tissue Engineering

The rapid development of tissue engineering and regenerative medicine has introduced a new strategy for ear reconstruction, successfully regenerating human-ear-shaped cartilage and achieving the first clinical breakthrough using a polyglycolic acid/polylactic acid (PGA/PLA) scaffold. However, its clinical repair varies greatly among individuals, and the quality of regenerated cartilage is unstable, which seriously limits further clinical application. Acellular cartilage matrix (ACM), with a cartilage-specific microenvironment, good biocompatibility, and potential to promote cell proliferation, has been used to regenerate homogeneous ear-shaped cartilage in immunocompromised nude mice. However, there is no evidence on whether ACM will regenerate homogeneous cartilage tissue in large animals or has the potential for clinical transformation. In this study, xenogeneic ACM assisted with gelatin (GT) with or without autologous chondrocytes was implanted subcutaneously into goats to establish a xenotransplantation model and compared with a PGA/PLA scaffold to evaluate the immune-inflammatory response and quality of regenerated cartilage. The results confirmed the superiority of the ACM/GT, which has the potential capacity to promote cell proliferation and cartilage formation. Although there is a slight immune-inflammatory response in large animals, it does not affect the quality of the regenerated cartilage and forms homogeneous and mature cartilage. The current study provides detailed insights into the immune-inflammatory response of the xenogeneic ACM/GT and also provides scientific evidence for future clinical application of ACM/GT in cartilage tissue engineering.