An investigation of the fixation materials for cartilage frames in microtia

Update on Total Auricular Construction

LEARNING OBJECTIVES

After studying this article, the participant should be able to: 1. Understand principles of preoperative planning for microtia repair. 2. Understand key techniques for flap design, skin envelope dissection, framework creation, and donor-site reconstruction. 3. Describe important components of postoperative management.

SUMMARY

Total auricular construction remains a challenge for reconstructive surgeons. This article describes current surgical strategies and advancements for microtia construction. The authors' focus is to describe the several keys for success that are useful for young surgeons who wish to train themselves to create satisfactory results.

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.

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.

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.

The Effect of Absorbable and Non-Absorbable Sutures on Nasal Width Following Cinch Sutures in Orthognathic Surgery

Background: Non-absorbable materials (nylon) are always used in cinch sutures to maintain nasal width and to improve harmonious facial symmetry in orthognathic surgery. However, a few drawbacks of nylon materials have been clinically reported following orthognathic surgery, such as nasal irritation and exposure of the sutures. An absorbable material (PDS) has been proposed in cinch sutures, not only to avoid the complications of nylon but also to stabilize the nasal width for a long-term follow-up. Methods: Fifty-seven patients with Angle’s malocclusion classification III receiving orthognathic surgery were enrolled in this study. A non-absorbable material (nylon) and an absorbable material (PDS) were utilized for the cinch sutures. Pre-operative (T1) and post-operative six-month (T2) craniofacial 3D images were collected for all patients to measure the alar curvature (Ac) width and the alar base (Al) width. A significance level of p < 0.05 was applied in the statistical analysis. Results: With the approval of IRB, cinch suturing was performed with nylon in 29 patients and with PDS in 28 patients. Pre-operative Ac and Al distances showed no significant difference between these two groups. There were also no significant differences between the suture materials in the peri-operative change in nasal width, including Ac (nylon: 1.999 ± 1.40; PDS: 1.484 ± 0.97; p = 0.112) and Al (nylon: 1.861 ± 1.66; PDS: 1.115 ± 0.92; p = 0.056). Conclusions: For cinch sutures in orthognathic surgery, PDS can maintain the peri-operative nasal width similarly to nylon; additionally, it can be absorbed in a timely manner without the drawbacks of non-absorbable materials.

Cartilage Framework Fixation with 2-Octyl Cyanoacrylate in a Prelaminated Radial Forearm Free Flap Total Auricular Reconstruction

Autologous total auricular reconstruction requires an intricately sculpted, curved, and stacked cartilaginous framework implanted under healthy vascularized tissue. The ideal fixation technique would be readily available, easy to deploy, and free of complications. Commonly used sutures can fracture fragile pieces, inadequately maintain shape, or migrate. Steel wire can erode through soft tissues, extrude, fracture, or become infected. We successfully used 2-octyl cyanoacrylate alone to fixate an autologous costal cartilage framework designed for a total auricular reconstruction in an adult trauma patient. We had no sutures or wires in the final construct. The key aspects of our technique included the following: use of small aliquots, application only at cartilage-to-cartilage interfaces, use of temporary shaping (needles and lasso sutures), and avoidance of excess spillage of adhesive on any portion that would directly contact soft tissue. The framework was implanted into a prelaminated radial forearm free flap, which was then transferred to the head and neck region at a second stage. At two-year follow-up, the framework held satisfactory shape without any complications such as resorption, exposure, or infection.

Experimental study on maintaining the curvature of transplanted cartilage: Influence of the number of cartilage struts

BACKGROUND

When auriculoplasty is performed for microtia, wire often becomes exposed during the long postoperative period. We have investigated other materials for fixing cartilage. We previously reported that absorbable sutures are more appropriate than wire. The present animal experiments investigated the reasons why fixation of transplanted cartilage is maintained when using absorbable sutures.

METHODS

The costal cartilages of Sprague-Dawley rats were harvested, and three cartilage transplant models were prepared. After bending a costal cartilage into a U-shape, it was fixed by using only absorbable sutures as the control or was fixed by suturing one or two cross struts of cartilage to the U-shaped graft. Then the cartilages were subcutaneously transplanted into the backs of the rats. They were removed 8 weeks later, and the return rate of the bent cartilages was assessed.

RESULTS

The return rate was 74.0%, in the suture-only group (control), 27.9% in the one-strut group, and 8.3% in the two-strut group. When the sites of contact between the U-shaped graft and the cartilage struts were observed by light microscopy, adhesion of the two cartilages by fibrous connective tissue was observed.

CONCLUSION

U-shaped cartilage grafts demonstrated a smaller return rate when there was a larger contact area with the cartilage struts. Each strut was fixed by fibrous connective tissue at the contact site, thereby maintaining the shape of the graft. Thus, when creating a cartilage framework, it is important to fix the bent cartilage to the cartilage struts with a sufficiently large contact area.

Autologous cartilage microtia reconstruction: Complications and risk factors

BACKGROUND

The Brent or Nagata techniques of microtia reconstruction and their modifications involve complicated frameworks; therefore, complications are inevitable. The authors aimed to provide comprehensive knowledge regarding the occurrence, development, prognosis, risk factors, and treatment of complications.

METHODS

This study was a retrospective review of patients who underwent autologous cartilage microtia reconstruction at a single auricular plastic and reconstructive center between March 2005 and June 2016. Custom database software was used to process data from patients with microtia. Details of postoperative complications were collected during follow-up for analysis.

RESULTS

A total of 470 procedures (stage I) were performed on 429 patients. The mean (±SD) age at surgery was 12.27 ± 5.01 years (range, 6-32 years). The mean time to follow-up was 3.67 ± 2.45 years (range, 1-11 years). The complication rate was 2.98% (4/134) with the Brent technique and 12.2% (38/311) with the Nagata technique. A multivariate logistic regression analysis of complications of microtia reconstruction revealed that age, sex, and laterality were not associated with postoperative complications (p > 0.05). Surgical technique affected the incidence of complications. The Nagata technique resulted in a higher risk for complications (OR 6.14 [95% CI 1.63-23.19]; p < 0.01).

CONCLUSION

The development of complications was a dynamic process. There was a learning curve associated with autologous cartilage microtia reconstruction. Orthopedists or otologists aspiring to master microtia reconstruction should have a fundamental understanding of the procedure and be aware of possible complications.

Complication rate of autologous cartilage microtia reconstruction: a systematic review

Background:

Autologous cartilage has been widely accepted as the frame material of ear reconstruction for patients with microtia. Although rare, there are multiple complications related with the surgical reconstruction techniques. The authors performed a systematic review of the English literature of microtia reconstruction to determine significant surgical factors that are predictors of postoperative complications.

Methods:

A PubMed search using the terms “ear reconstruction” and “microtia” was conducted. Articles were screened using predetermined inclusion and exclusion criteria. Data collected included patient characteristics, surgical techniques, the incidence of all kinds of complications, and the specific postoperative morbidity. Patient cohorts were pooled, and the incidence of complications was calculated. Significant predictors such as the use of tissue expander, simultaneously mid-ear reconstruction, with/without skin graft, and different fascia coverage were analyzed by chi-square test.

Result:

Of 320 articles found, 60 met the inclusion criteria. Totally 9415 patients with microtia were analyzed in this review with 1525 cases with complications. The overall complication incidence is 16.2% in average with a range of 0–72.9%. There was no significant difference when comparing the overall complication rate between with/without preexpansion 2-stage and multiple-stage techniques or with/without mid-ear reconstruction simultaneously.

Conclusion:

Although there is little agreement in literature regarding risk factors for complications, the authors were able to demonstrate several significant predictors by systematically analyzing 60 articles. Improved knowledge of the incidence of different complications related with various surgical methods can help surgeons provide improved preoperative counseling and take measures to minimize the risk.