Cartilage exposure following autologous microtia reconstruction: An algorithmic treatment approach✰

Exploring Aesthetic Outcomes and Complications in Auricular Reconstruction Utilising Autologous Cartilage: A Systematic Review and Narrative Synthesis

Auricular reconstruction remains a challenging procedure, requiring a high degree of manual dexterity and attention to detail in order to reconstruct the complex three-dimensional geometry of the ear successfully. Most techniques will rely on autologous cartilage for auricular framework fabrication, carrying a risk of donor and recipient site morbidity. The aim of this report is to investigate the complications and aesthetic outcomes associated with autologous cartilage harvest in auricular reconstruction. A systematic review protocol was registered with the International Prospective Register of Systematic Reviews (PROSPERO) and reported in accordance with the Preferred Reporting for Items for Systematic Reviews and Meta-Analyses. Comprehensive electronic search strategies for four databases were developed. Studies were screened according to the inclusion and exclusion criteria by two independent reviewers. The literature search identified 7171 articles. Filtering for relevance and duplication reduced the number of articles to 52. A total of 12,215 patients underwent auricular reconstruction utilising autologous cartilage. Indications included 11,696 patients due to microtia, 334 patients due to burns or trauma, 70 patients due to constricted ears, and 115 patients due to prominent ears. The most commonly reported donor site complications included chest wall deformities (n = 159). The most commonly reported recipient site complications included hypertrophic or keloid scars (n = 279), haematoma (n = 155), tissue expander exposure (n = 111), cartilage or framework exposure (n = 122), and cartilage framework deformation or resorption (n = 50). Although a challenging procedure, auricular reconstruction utilising autologous cartilage is possible. Exceptional aesthetic results can be achieved when performed by a skilled surgeon on appropriately selected individuals. However, the potential risks and complications associated with the procedure should be discussed with the patient and family beforehand.

Salvage of Ear Framework Exposure Following Autologous Microtia Reconstruction: Repair Strategy for Each Location of Exposure

One of the most common complications of total auricular reconstruction is exposure of the ear framework. Various reconstruction methods have been reported depending on the location and size of exposed cartilage. This report describes a safe reconstruction method for each exposed part of the grafted ear framework. From January 2019 to August 2021, 2 cases (4 areas) of framework exposure were observed following autologous microtia reconstruction. The first case developed 2 small areas of skin necrosis on the anterior helix and lower antihelix to concha. The former was reconstructed with a temporal fascia flap and the latter with a local transposition flap. The second case also developed 2 small areas of skin necrosis on the posterior helix and lower antihelix to concha. The former was sutured directly and the latter with a local transposition flap. However, both wounds recurred due to flap necrosis and the cartilage was exposed again. The 3rd operation was performed by covering both wounds with a posterior auricular turnover flap and skin graft. In both cases, the exposed framework was completely covered with the flaps, and the reconstructed ears showed well-defined convolutions. Covering exposed cartilage with a local flap with a random pattern of blood circulation is convenient because no additional skin grafts are required. However, the blood circulation of the flaps is inadequate when an elongated flap is required; consequently, flap necrosis may occur. On the other hand, a temporal fascia flap and posterior auricular flap, which have axillary pattern blood circulation, are considered to be safer. We believe that it is safe to use a temporal fascia flap for cartilage exposure in the upper half of the auricle, and a posterior auricular turnover flap for the lower half.

Dual Option Microtia Clinic: A Comparison of Outcomes in Microtia Reconstruction Using Autologous Rib or Porous Polyethylene Implant

Introduction: Auricular reconstruction techniques most frequently utilize either autologous costal cartilage or alloplastic porous polyethylene (PPE) implant. Objectives: To compare the aesthetic outcomes, number of surgeries, and complications in children who underwent microtia reconstruction with either rib or PPE implant by blinded photograph review. Methods: This retrospective cohort study included consecutive pediatric patients who underwent auricular reconstruction with either autologous cartilage or PPE between November 2017 and February 2022. Blinded observers rated each postoperative ear through a web-based survey. Data on patient characteristics, operative time, length of admission, and complications were collected, bivariate analyses were performed using chi-square or Fisher's exact tests for categorical variables and Wilcoxon rank-sum test for continuous variables. Results: Forty-four ears were included, 28 of which (63.6%) were reconstructed with cartilage. Median patient age was 8 years (range 4-18 years) and 29 (65.9%) were male. The cartilage group had more surgeries (median 2.5 vs. 1.0, p < 0.001), and total operating time across all surgeries did not differ significantly. Conclusion: The two groups in our study had similar rates of complications and aesthetic scores, and aesthetic scores were worse for ears with wound complications requiring unplanned revisions.

An Unusual Delayed Complication of Rib Graft Microtia Reconstruction After Two Decades: A Case Report

Microtia comprises a spectrum of congenital malformation characterized by partial deformities of the auricular components to complete absence of pinna. Surgical reconstructions of this anomaly are often complex and technically challenging. Infection, hematoma, and skin necrosis with resultant exposed cartilage graft tend to occur in the early phase of post-operative care. Herein, we report a case of a spontaneous auricular abscess with exposed cartilage framework 20 years following rib cartilage reconstruction. To our knowledge, this is the first case of such an occurrence. The treatment options are discussed, along with the review of the literature.

Anthropometric assessment of microtia patients' normal ears and discussion on expander selection in auricular reconstruction surgery

The tissue expansion technique is the most suitable procedure for Chinese patients with microtia. However, it is difficult to determine whether the expanded flap is sufficient, and there are no clear or objective guidelines for determining the volume of the expander for different sizes of auricles. One hundred patients with unilateral microtia who visited our department in 2021 were randomly selected for auricular data collection using 3D scanning. The auricle length, width, projection, perimeter, and surface area were measured. Eight different volumes of expanders underwent CT and the surface areas of these expanders were measured. The surface areas of the auricles and expanders were compared and the correlation between them was explored. The average auricle parameters were calculated. The scatter plot showed a linear relationship between auricle length and auricle surface area (R² = 0.9913), which demonstrated that the auricle area was approximately equal to the auricle length multiplied by 76.921. Additionally, the surface area of the expanders was measured and made into a table for selection against the surface area of the auricles. Using our equation, the auricle surface could be estimated by simply measuring the non-defective auricle length; therefore, the suitable volume of the expander could be determined.

Secondary surgery for the unsatisfactory auricle after auricular reconstruction

OBJECTIVES

Complications, including framework exposure, infections, and reconstructed auricle deformation, may occur after auricular reconstruction. However, reports on surgical methods for cases with unsatisfactory outcomes after auricular reconstruction using an autologous costal cartilage are insufficient. Herein, we summarized retreatment casesfor poor ear morphology in patients who had undergone auricular reconstruction in our department for 5 years and discussed other techniques.

METHODS

Between September 2014 and September 2019, 24 ears of 24 patients with poor morphology, unsatisfactory macroscopic characteristics and anatomical structures, and unsatisfactory outcomes of local repair after auricular reconstructive surgery were treated. Patients were divided into the following three groups: type 1 (9 ears), with intact and sufficient hairless skin in the mastoid region behind the reconstructed ear; type 2 (7 ears), with intact, but insufficient, hairless skin in the mastoid region behind the reconstructed ear; and type 3 (8 ears), with hairless skin in the mastoid region behind the reconstructed ear with impaired skin integrity.

RESULTS

Twenty-two (91.6%) patients successfully completed the surgical treatment and recovered well; one experienced delayed wound healing and another developed hypertrophic scarring at the incision site at 3 months postoperatively. All patients were followed for 0.5-4 (mean, 2.8) years. The macrostructure of the reconstructed ear post-revision was stable and significantly improved in terms of morphology and structure.

CONCLUSIONS

In patients with unsatisfactory outcomes after auricular reconstruction, the appropriate technique for the revision surgery should consider the local soft tissue conditions of the reconstructed ear to obtain satisfactory results.

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.

Long-term aesthetics, patient-reported outcomes, and auricular sensitivity after microtia reconstruction: A systematic review

BACKGROUND

Auricular reconstruction for microtia is most frequently performed using autologous costal cartilage (ACC) or porous polyethylene (PPE) implants. Short-term results are generally promising, but long-term results remain unclear. Long-term outcomes were explored in this systematic review, and minimal reporting criteria were suggested for future original data studies.

METHODS

A systematic literature search was conducted in MEDLINE, EMBASE, and the Cochrane Central Register of Controlled Trials from inception through October 14, 2020. Articles on auricular reconstruction in patients with microtia using ACC or PPE were included if postsurgical follow-up was at least 1 year. Outcome reporting was split into separate publications, and results on complications were reported previously. This publication focused on long-term aesthetic, patient-reported, and sensitivity outcomes.

RESULTS

Forty-one publications reported on these outcomes. Both materials led to aesthetically pleasing results and high rates of patient satisfaction. ACC frameworks grew similarly to contralateral ears, and the anterior surface of auricles regained sensitivity. Furthermore, postoperative health-related quality of life (HRQoL) outcomes were generally good. Data synthesis was limited due to considerable variability between studies and poor study quality. No conclusions could be drawn on the superiority of either method due to the lack of comparative analyses.

CONCLUSION

Future studies should minimally report (1) surgical efficacy measured using the tool provided in the UK Care Standards for the Management of Patients with Microtia and Atresia; (2) complications including framework extrusion or exposure, graft loss, framework resorption, wire exposure and scalp/auricular scar complications and (3) HRQoL before and after treatment using the EAR-Q patient-reported outcome measure (PROM).

Long-term complications of microtia reconstruction: A systematic review

BACKGROUND

Microtia is a rare disorder characterized by malformation or even complete absence of the auricle. Reconstruction is often performed using autologous costal cartilage (ACC) or porous polyethylene implants (PPE). However, the long-term outcomes of both methods are unclear.

OBJECTIVE

This systematic review aimed to analyze long-term complications and suggest minimal reporting criteria for future original data studies.

METHODS

A systematic literature search was conducted in MEDLINE, EMBASE and the Cochrane Central Register of Controlled Trials from inception through October 14, 2020. Articles on auricular reconstruction in patients with microtia using ACC or PPE were included provided that the follow-up period was at least one year. This publication focused on long-term complications reported in patients with a postoperative follow-up period of at least one year.

RESULTS

Twenty-nine publications reported on complications during long-term follow-up. Overall long-term complication rates were not reported. The incidence of individual complications during long-term follow-up was less than 10% after ACC reconstruction and less than 15% in PPE reconstruction. Framework resorption and wire exposure were reported even after an extended follow-up of more than five years after ACC reconstruction, while reports on the extended long-term results of PPE reconstruction are limited. Data synthesis was limited due to heterogeneity and poor study quality.

CONCLUSIONS

Future studies should report on long-term complications including framework exposure or extrusion, graft loss, framework resorption, wire exposure and scalp and auricular scar complications. We recommend a surgical follow-up of at least five years.

New strategies for base frame fabrication in microtia reconstruction

The base frame provides a stable support for the helix, antihelix, and tragus–antitragus complex in microtia reconstruction, and this support is vital to attain a highly defined outline for a reconstructed auricle. The success of base frame sculpting depends on appropriate treatment of the cartilage, mainly the sixth and seventh costal cartilages, which may have different characteristics. The aim of this study was to demonstrate the relevant details for base frame fabrication under various scenarios. Between 2016 and 2019, a total of 352 patients with microtia underwent autologous auricular reconstruction. Concerning the different sizes and characteristics of the costal cartilage used for the base frame reconstruction, we describe the related methods for fabrication and introduce corresponding strategies for proper management. We found that 90% of the patients responded at follow-up, and 76% of them were satisfied with the cosmetically refined auricle with harmonious integrity. The elaborate design and appropriate utilization of costal cartilage for base frame sculpting is one of the most significant and fundamental processes in microtia reconstruction. It contributes to achieving a clearly defined outline of the auricle with harmonious integrity, which is as important as the other projected subunits.

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.

Biofabrication of a shape-stable auricular structure for the reconstruction of ear deformities

Bioengineering of the human auricle remains a significant challenge, where the complex and unique shape, the generation of high-quality neocartilage, and shape preservation are key factors. Future regenerative medicine–based approaches for auricular cartilage reconstruction will benefit from a smart combination of various strategies. Our approach to fabrication of an ear-shaped construct uses hybrid bioprinting techniques, a recently identified progenitor cell population, previously validated biomaterials, and a smart scaffold design. Specifically, we generated a 3D-printed polycaprolactone (PCL) scaffold via fused deposition modeling, photocrosslinked a human auricular cartilage progenitor cell–laden gelatin methacryloyl (gelMA) hydrogel within the scaffold, and cultured the bioengineered structure in vitro in chondrogenic media for 30 days. Our results show that the fabrication process maintains the viability and chondrogenic phenotype of the cells, that the compressive properties of the combined PCL and gelMA hybrid auricular constructs are similar to native auricular cartilage, and that biofabricated hybrid auricular structures exhibit excellent shape fidelity compared with the 3D digital model along with deposition of cartilage-like matrix in both peripheral and central areas of the auricular structure. Our strategy affords an anatomically enhanced auricular structure with appropriate mechanical properties, ensures adequate preservation of the auricular shape during a dynamic in vitro culture period, and enables chondrogenically potent progenitor cells to produce abundant cartilage-like matrix throughout the auricular construct. The combination of smart scaffold design with 3D bioprinting and cartilage progenitor cells holds promise for the development of clinically translatable regenerative medicine strategies for auricular reconstruction.

•

First application of human auricular cartilage progenitor cells for bioprinting.

•

Dual-printing of hybrid ear-shaped constructs with excellent shape fidelity over time.

•

Strategy and design ensured adequate deposition of cartilage-like matrix throughout large auricular constructs.

Modification of the cartilaginous framework for autologous ear reconstruction: Construction of a stable complete ring framework with grander highs and lows

BACKGROUND

Successful microtia reconstruction involves fabrication of a framework with well-defined ear subunits. Tragal definition and deep conchal bowl are key elements to produce a natural well-defined and contoured ear. We describe a modification in the cartilage framework with the purpose of increasing framework stability, tragal definition and conchal bowl depth.

METHODS

The tragus is placed on two cartilaginous bars (L-shaped), which are fixed to the framework base block creating a complete ring. These increase tragal projection and conchal depth. The tragus is carved angled posteriorly to have a shadowing effect on the absent auditory canal. Aesthetic outcome was assessed, at least 6 months after the second stage, on a 5-point ordinal scale (1-5) using the scoring system published in the UK microtia care standards and agreed on by the International Society for Auricular Reconstruction (ISAR).

RESULTS

A total of 406 auricular reconstructions were performed in 363 patients (206 right, 114 left, 43 bilateral). After excluding cases who did not have second stage and those without complete photographs, 290 cases were assessed. The described modification in the framework carving was performed in 255 ears out of these 290 ears. The mean aesthetic score before and after the modification was 2.4 and 3.09 respectively for the tragus (p < 0.001), 2.2 and 2.95 for the intertragal notch (p < 0.001) and 2.77 and 3.49 for the concha (p < 0.001).

CONCLUSIONS

This technical refinement has resulted in increased permanence and definition of the tragus and deeper and more aesthetic concha.

Repair of damage to the skin flap during total auricular reconstruction with tissue expansion

INTRODUCTION

Auricular reconstruction with tissue expansion has been widely used in children with microtia. Base on the experience of using tissue expander, more patients have undergone a modified auricular reconstruction using a framework wrapped by expanded skin flap without fascial and skin graft transplantation. Skin damage is a common complication that may lead to serious outcomes, such as infection and distortion. Promptly repair is particularly important when using this modified technique. This work aims to record the site and other information on damage to the expanded skin flap, and to apply various salvage methods according to the site and stage.

METHODS

From January 2017 to September 2019, 170 patients who underwent total auricular reconstruction without fascial and skin graft were followed up. All patients who had skin damage received corresponding prompt treatment. Details on the site, occurrence time, and salvage methods were noted.

RESULTS

A total of 19 patients were found to have skin damage during the follow-up period. The defect size ranged from 10 mm² to 70 mm². Four patients had skin damage in the lower part of the skin flap combined with expander exposure. The second stage of auricular reconstruction was carried out immediately. Two patients had skin flap damage in anterior 1/3rd of the helix, seven in middle 1/3rd of the helix, four in posterior 1/3rd of the helix and two in the triangular fossa. Most of the skin damage occurred within 4-9 months after auricular reconstruction. According to the site and other factors, the expanded skin flap with the exposed cartilage was repaired using local skin flap, retroauricular skin flap, and retroauricular fascia. Patients were satisfied with the outcome of the repair. Additional skin damage and other complications were not observed after the repair operations.

CONCLUSION

Skin damage is a common complication, and it should receive more attention while applying this modified auricular reconstruction using tissue expansion. The site, occurrence time, and other information provide reference to improve the reconstruction without fascial or skin graft transplantation. Salvage methods, such as retroauricular skin flap and retroauricular fascia, have been treated as highly efficient backup methods and have achieved satisfying results.