Ear reconstruction after auricular chondritis secondary to ear piercing

The recent fad of high ear piercing in the pinna has led to an increased incidence of auricular chondritis, which leads to dissolution of the cartilage and residual ear deformity. The typical postpiercing chondritis deformity presents as a structural collapse of the superior helical rim, scaphal cartilage, and the adjacent antihelix. The skin envelope is usually preserved, but it may be scarred from the infectious process and from previous drainage incisions. In the present article, the authors present a systematic approach to reconstruction of these acquired ear deformities. Careful assessment of the residual tissue is requisite to planning and appropriate reconstruction. The greater the cartilage loss, the more structural support is required to expand the skin envelope to its normal size and shape. The choice of cartilage donor site is made on the basis of the size of the defect and may include ipsilateral or contralateral conchal cartilage, bilateral conchal cartilage, or costal cartilage. Redraping of the carefully dissected skin and fixation of the flaps to the newly reconstructed cartilaginous framework usually provide sufficient soft-tissue coverage. A temporal-parietal fascial flap is preserved for the rare cases of extensive full-thickness skin loss or badly damaged and scarred auricular skin.     

Tissue engineering: revolution and challenge in auricular cartilage reconstruction

External ear reconstruction for congenital deformity such as microtia or following trauma remains one of the greatest challenges for reconstructive plastic surgeons. The problems faced in reconstructing the intricate ear framework are highly complex. A durable, inert material that is resistant to scar contracture is required. To date, no material, autologous or prosthetic, is available that perfectly mimics the shapely elastic cartilage found in the ear. Current procedure involves autologous costal cartilage that is sculpted to create a framework for the overlying soft tissues. However, this is associated with donor-site morbidity, and few surgeons worldwide are skilled in the techniques required to obtain excellent results. Various alloplastic materials have therefore been used as a framework. However, a degree of immunogenicity and infection and extrusion are inevitable, and results are often disappointing. Tissue-engineered cartilage is an alternative approach but, despite significant progress in this area, many problems remain. These need to be addressed before routine clinical application will become possible. The current tissue-engineered options are fragile and inflexible. The next generation of auricular cartilage engineering is promising, with smart materials to enhance cell growth and integration, and the application of stem cells in a clinical setting. More recently, the authors' team designed the world's first entirely synthetic trachea composed of a novel nanocomposite material seeded with the patient's own stem cells. This was successfully transplanted in a patient at the Karolinska Hospital in Sweden and may translate into a tissue-engineered auricle in the future.     

In vitro redifferentiation of culture-expanded rabbit and human auricular chondrocytes for cartilage reconstruction

To construct an autologous cartilage graft using tissue engineering, cells must be multiplied in vitro; they then lose their cartilage-specific phenotype. The objective of this study was to assess the capacity of multiplied ear chondrocytes to re-express their cartilage phenotype using various culture conditions. Cells were isolated from the cartilage of the ears of three young and three adult rabbits and, after multiplication in monolayer culture, they were seeded in alginate and cultured for 3 weeks in serum-free medium with insulin-like growth factor 1 (IGF-1) and transforming growth factor-beta2 (TGF-beta2) in three different dose combinations. As a control, cells were cultured in 10% fetal calf serum, which was demonstrated in previous experiments to be unable to induce redifferentiation. Chondrocytes from the ears of young, but not adult, rabbits, synthesized significantly more glycosaminoglycan when serum was replaced by insulin-like growth factor-1 and transforming growth factor-beta2. The number of collagen type II-positive cells was increased from 10 percent to 97 percent in young cells and to 33 percent in adult cells. Using human ear cells from 12 patients (aged 7 to 60 years), glycosaminoglycan synthesis could also be stimulated by replacing serum with insulin-like growth factor and transforming growth factor-beta. Although the number of collagen type II-positive cells could be increased under these conditions, it never reached above 10 percent. Data from five patients showed that further optimization of the culture conditions by adding ITS+ and cortisol significantly increased (doubled or tripled) both glycosaminoglycan synthesis and collagen type II expression. In conclusion, this study demonstrates a method to regain cartilage phenotype in multiplied ear cartilage cells. This improves the chances of generating human cartilage grafts for the reconstruction of external ears or the repair of defects of the nasal septum.     

Nasal reconstruction using both cranial bone and ear cartilage

In this article, an anatomic reconstruction is described using cranial bone graft for the bony part of the nose while reconstructing the cartilaginous part with ear cartilage. This modification provides protection of the nose from the traumatic forces creating a flexible nasal tip. A modification is described and compared with the nasal reconstruction by calvarial bone itself.     

Characterization of pediatric microtia cartilage: a reservoir of chondrocytes for auricular reconstruction using tissue engineering strategies

The external ear is composed of elastic cartilage. Microtia is a congenital malformation of the external ear that involves a small reduction in size or a complete absence. The aim of tissue engineering is to regenerate tissues and organs clinically implantable based on the utilization of cells and biomaterials. Remnants from microtia represent a source of cells for auricular reconstruction using tissue engineering. To examine the macromolecular architecture of microtia cartilage and behavior of chondrocytes, in order to enrich the knowledge of this type of cartilage as a cell reservoir. Auricular cartilage remnants were obtained from pediatric patients with microtia undergoing reconstructive procedures. Extracellular matrix composition was characterized using immunofluorescence and histological staining methods. Chondrocytes were isolated and expanded in vitro using a mechanical-enzymatic protocol. Chondrocyte phenotype was analyzed using qualitative PCR. Microtia cartilage preserves structural organization similar to healthy elastic cartilage. Extracellular matrix is composed of typical cartilage proteins such as type II collagen, elastin and proteoglycans. Chondrocytes displayed morphological features similar to chondrocytes derived from healthy cartilage, expressing SOX9, COL2 and ELN, thus preserving chondral phenotype. Cell viability was 94.6 % during in vitro expansion. Elastic cartilage from microtia has similar characteristics, both architectural and biochemical to healthy cartilage. We confirmed the suitability of microtia remnant as a reservoir of chondrocytes with potential to be expanded in vitro, maintaining phenotypical features and viability. Microtia remnants are an accessible source of autologous cells for auricular reconstruction using tissue engineering strategies.     

Characteristics of cartilage engineered from human pediatric auricular cartilage

In the repair of cartilage defects, autologous tissue offers the advantage of lasting biocompatibility. The ability of bovine chondrocytes isolated from hyaline cartilage to generate tissue-engineered cartilage in a predetermined shape, such as a human ear, has been demonstrated; however, the potential of chondrocytes isolated from human elastic cartilage remains unknown. In this study, the authors examined the multiplication characteristics of human auricular chondrocytes and the ability of these cells to generate new elastic cartilage as a function of the length of time they are maintained in vitro. Human auricular cartilage, harvested from patients 5 to 17 years of age, was digested in collagenase, and the chondrocytes were isolated and cultured in vitro for up to 12 weeks. Cells were trypsinized, counted, and passaged every 2 weeks. Chondrocyte-polymer (polyglycolic acid) constructs were created at each passage and then implanted into athymic mice for 8 weeks. The ability of the cells to multiply in vitro and their ability to generate new cartilage as a function of the time they had been maintained in vitro were studied. A total of 31 experimental constructs from 12 patients were implanted and compared with a control group of constructs without chondrocytes. In parallel, a representative sample of cells was evaluated to determine the presence of collagen. The doubling rate of human auricular chondrocytes in vitro remained constant within the population studied. New tissue developed in 22 of 31 experimental implants. This tissue demonstrated the physical characteristics of auricular cartilage on gross inspection. Histologically, specimens exhibited dense cellularity and lacunae-containing cells embedded in a basophilic matrix. The specimens resembled immature cartilage and were partially devoid of the synthetic material of which the construct had been composed. Analyses for collagen, proteoglycans, and elastin were consistent with elastic cartilage. No cartilage was detected in the control implants. Human auricular chondrocytes multiply well in vitro and possess the ability to form new cartilage when seeded onto a three-dimensional scaffold. These growth characteristics might some day enable chondrocytes isolated from a small auricular biopsy to be expanded in vitro to generate a large, custom-shaped, autologous graft for clinical reconstruction of a cartilage defect, such as for congenital microtia.     

Tension lines of the auricular cartilage

Utilizing Langer's technique for skin tension lines, we punctured the auricular cartilage of 10 human cadavers and 2 mature rabbits and 24 immature rabbits with a conical awl to determine their tension lines. Deformation of the holes into straight lines indicated the direction of maximum tension. A regular pattern was observed in adult rabbits and humans: Tension was at right angles to the long axis at the auricular base and parallel at the apex. This pattern was not present at birth, but developed at 1 to 2 weeks of age in rabbits. It is felt that these tension lines are responsible for the clinical results of auricular reconstruction. In children less than 1 week of age, tension lines are disorganized so that nonsurgical correction will be successful as long as hypoplasia is not present. In older children, correction will be successful when the deformity is parallel to the tension lines.