Laser-assisted cartilage reshaping for protruding ears: A review of the clinical applications

Geometric Reconstruction of Cartilage Tissue With Mesenchymal Stem Cell-Assisted Electromechanical Reshaping: An Experimental Study

ABSTRACT

Shaping the ear cartilage and preserving the shape are important and quite difficult. The aim of this study was to demonstrate the effectiveness of the Wharton's jelly-derived stem cell-assisted electromechanical reshaping method in a rabbit ear cartilage defect model and to compare it with surgical reshaping.For the purpose of 25 × 4-mm cartilage defect reconstruction, 48 rabbit ears were divided into 2 main groups according to the shaping method, and these main groups were divided into 3 subgroups according to stem cell injection: control, sham, and stem cell.A rabbit ear cartilage defect was created, and rib cartilage was collected for reconstruction. Although electromechanical reshaping was performed in accordance with the rabbit ear geometry angle, surgical scoring and suturing were performed in the classical method. Stem cells were applied in the first week, and the grafts were removed in the first month. Analyses included angular change, weight change, and histopathology.In this study, electromechanical reshaping was histopathologically similar to surgical reshaping and is more effective in preserving the shape. Cartilage thickness and weight were higher in stem cell groups.Electromechanical reshaping is emerging as an effective and standardized method to maintain cartilage stability and geometry and offers a viable alternative to classic surgical techniques. In addition, stem cell application gave physical strength to cartilage. It is a method that allows us to obtain more stable and more durable cartilages that maintain given shape with the combination of Wharton jelly-assisted electromechanical reshaping method.

1064nm Nd:YAG laser promotes chondrocytes regeneration and cartilage reshaping by upregulating local estrogen levels

Cartilage is frequently used as a scaffolds for repairing and reconstructing body surface organs. However, after successful plastic surgery, transplanted cartilage scaffolds often exhibit deformation and absorption over time. To enhance the shaping stability of cartilage scaffolds and improve patients' satisfaction after reconstructions, we employed the ear folding models in New Zealand rabbits to confirm whether the 1064nm neodymium-doped yttrium aluminum garnet (Nd:YAG) laser could promote cartilage reshaping. There was an increase in collagen and aromatase (Cyp19) expression within the ear cartilage after laser treatment. Moreover, we have found that the Cyp19 inhibitor can inhibit the laser's effect on cartilage shaping and reduce collagen and Cyp19 expression. The overall findings suggest that treatment with 1064nm Nd:YAG laser irradiation can enhance estrogen levels in local cartilage tissues by upregulating Cyp19 expression in chondrocytes through photobiomodulation, thereby promoting the proliferation and collagen secretion of chondrocytes to improve cartilage reshaping and stability.

Laser surface modification of decellularized extracellular cartilage matrix for cartilage tissue engineering

The implantation of autologous cartilage as the gold standard operative procedure for the reconstruction of cartilage defects in the head and neck region unfortunately implicates a variety of negative effects at the donor site. Tissue-engineered cartilage appears to be a promising alternative. However, due to the complex requirements, the optimal material is yet to be determined. As demonstrated previously, decellularized porcine cartilage (DECM) might be a good option to engineer vital cartilage. As the dense structure of DECM limits cellular infiltration, we investigated surface modifications of the scaffolds by carbon dioxide (CO₂) and Er:YAG laser application to facilitate the migration of chondrocytes inside the scaffold. After laser treatment, the scaffolds were seeded with human nasal septal chondrocytes and analyzed with respect to cell migration and formation of new extracellular matrix proteins. Histology, immunohistochemistry, SEM, and TEM examination revealed an increase of the scaffolds' surface area with proliferation of cell numbers on the scaffolds for both laser types. The lack of cytotoxic effects was demonstrated by standard cytotoxicity testing. However, a thermal denaturation area seemed to hinder the migration of the chondrocytes inside the scaffolds, even more so after CO₂ laser treatment. Therefore, the Er:YAG laser seemed to be better suitable. Further modifications of the laser adjustments or the use of alternative laser systems might be advantageous for surface enlargement and to facilitate migration of chondrocytes into the scaffold in one step.

The Protruding Ear: Cosmetic and Reconstruction

Ear prominence is a relatively common cosmetic deformity with no associated functional deficits, but with profound psychosocial impact, especially in young patients. Protruding ears in children have propagated surgical advances that incorporate reconstructive techniques. Here we outline a systematic framework to evaluate the protruding ear and present various reconstructive surgical options for correction. Both cosmetic and reconstructive perspectives should be entertained when addressing this anatomical deformity.

Optimal Electromechanical Reshaping of the Auricular Ear and Long-term Outcomes in an In Vivo Rabbit Model

IMPORTANCE

The prominent ear is a common external ear anomaly that is usually corrected through surgery. Electromechanical reshaping (EMR) may provide the means to reshape cartilage through the use of direct current (in milliamperes) applied percutaneously with needle electrodes and thus to reduce reliance on open surgery.

OBJECTIVE

To determine the long-term outcomes (shape change, cell viability, and histology) of a more refined EMR voltage and time settings for reshaping rabbit auricle.

DESIGN, SETTING, AND SUBJECTS

The intact ears of 14 New Zealand white rabbits were divided into 2 groups. Group 1 received 4 V for 5 minutes (5 ears), 5 V for 4 minutes (5 ears), or no voltage for 5 minutes (control; 4 ears). Group 2 received an adjusted treatment of 4 V for 4 minutes (7 ears) or 5 V for 3 minutes (7 ears). A custom mold with platinum electrodes was used to bend the pinna and to perform EMR. Pinnae were splinted for 6 months along the region of the bend. Rabbits were killed humanely and the ears were harvested the day after splint removal. Data were collected from March 14, 2013, to July 8, 2014, and analyzed from August 29, 2013, to March 1, 2015.

MAIN OUTCOMES AND MEASURES

Bend angle and mechanical behavior via palpation were recorded through photography and videography. Tissue was sectioned for histologic examination and confocal microscopy to assess changes to microscopic structure and cell viability.

RESULTS

Rabbits ranged in age from 6 to 8 months and weighed 3.8 to 4.0 g. The mean (SD) bend angles were 81° (45°) for the controls and, in the 5 EMR groups, 72° (29°) for 4 V for 4 minutes, 101° (19°) for 4 V for 5 minutes, 78° (18°) for 5 V for 3 minutes, and 126° (21°) for 5 V for 4 minutes. At 5 V, an increase in application time from 3 to 4 minutes provided significant shape change (78° [18°] and 126° [21°], respectively; P = .003). Pinnae stained with hematoxylin-eosin displayed localized areas of cell injury and fibrosis in and around electrode insertion sites. This circumferential zone of injury (range, 1.3-2.1 mm) corresponded to absence of red florescence on the cell viability assay.

CONCLUSIONS AND RELEVANCE

In this in vivo study, EMR produces shape changes in the intact pinnae of rabbits. A short application of 4 V or 5 V can achieve adequate reshaping of the pinnae. Tissue injury around the electrodes is modest in spatial distribution. This study provides a more optimal set of EMR variables and a critical step toward evaluation of EMR in clinical trials.

LEVEL OF EVIDENCE

NA.

Injectable chondroplasty: Enzymatic reshaping of cartilage grafts

OBJECTIVE/HYPOTHESIS

To develop an injection-based enzymatic technique that selectively softens cartilage tissue for reshaping cartilaginous structures in the head and neck.

MATERIALS AND METHODS

Two groups were formed using fresh rabbit ears: (1) whole rabbit ear group; (2) composite graft group (2.5mm×3.0cm specimens sectioned from the central region of the pinna). Subperichondrial injections using three enzymes (hyaluronidase, pronase, and collagenase II) in sequence were performed for the experimental specimens from both groups. In the control specimens, phosphate buffered saline was injected in a similar fashion. The whole ear specimens were then photographed while held upright in the anatomical vertical position to evaluate for buckling, which corresponds to the integrity of the cartilage. In addition, backlight photography was performed for all specimens to further evaluate the effect of the enzymes, such that increased light intensity represents increased cartilage digestion.

RESULTS

The application of the digestive enzymes resulted in marked reduction of cartilage tissue matrix resiliency, while preserving overlying skin layers. Enzymatically treated whole pinnae buckled at the site where enzymes were delivered. Backlit images revealed increased local light intensity at the regions of digestion. There was no obvious destruction of the overlying skin upon visual inspection.

CONCLUSIONS

This study demonstrates the feasibility of injectable chondroplasty as a potential alternative method to conventional surgery for auricular cartilage reshaping. Sequential injection of hyaluronidase, pronase, and collagenase II into the subperichondrial space can be performed to digest and soften cartilage structure with minimal involvement of surrounding tissue. Future studies will need to include chondrocyte viability testing and optimization of delivery techniques.