Ear Graft Research Articles

Utility of 3D CT Rib Study in Presurgical Planning of Autologous Ear Graft for Pinna Reconstruction in Microtia

Purpose The aim of this study was to demonstrate the utility of three-dimensional computed tomography (3D) CT rib study in presurgical planning to select the autologous rib cartilage graft for pinna reconstruction. Materials and Methods Total of 35 patients of microtia for autologous rib graft from April 2017 to February 2020 were evaluated in this study. All patients had a plain low-dose multislice CT chest. The length of costal cartilages of sixth to ninth ribs bilaterally and width and height of sixth and seventh rib costal cartilage synchondrosis were measured in 3D reconstructed true size coronal images with best possible length displayed. All patients had high-resolution computed tomography (HRCT) temporal studies done to evaluate for associated anomalies in external canal, middle ear cavities, and inner ear structures. Eleven patients had simultaneous HRCT temporal bone done after plain CT chest and rest who had done recent prior study were reviewed without repetition of study. Results There were 19 males and 16 females for 3D CT rib study. Average age of the participants was 16.5 years. The average width of synchondrosis of sixth and seventh rib was 15.4 mm on right side and 14.7 mm on left side, average height of synchondrosis was 28.5 mm on right side and 30.7 mm on left side. Average length of the eighth rib costal cartilage was 88.6 mm on the right side and 90.5 mm on the left side. Average length of the ninth rib was 63.2 mm on the right side and 58.2 mm on the left side. Costal cartilage calcifications were present in 9 patients. Conclusion Preoperative 3D CT rib study provides accurate measurements of rib stock for sculpting autologous ear graft.

Perfusion-decellularization of human ear grafts enables ECM-based scaffolds for auricular vascularized composite tissue engineering

Introduction: Human ear reconstruction is recognized as the emblematic enterprise in tissue engineering. Up to now, it has failed to reach human applications requiring appropriate tissue complexity along with an accessible vascular tree. We hereby propose a new method to process human auricles in order to provide a poorly immunogenic, complex and vascularized ear graft scaffold.Methods: 12 human ears with their vascular pedicles were procured. Perfusion-decellularization was applied using a SDS/polar solvent protocol. Cell and antigen removal was examined by histology and DNA was quantified. Preservation of the extracellular matrix (ECM) was assessed by conventional and 3D-histology, proteins and cytokines quantifications. Biocompatibility was assessed by implantation in rats for up to 60 days. Adipose-derived stem cells seeding was conducted on scaffold samples and with human aortic endothelial cells whole graft seeding in a perfusion-bioreactor.Results: Histology confirmed cell and antigen clearance. DNA reduction was 97.3%. ECM structure and composition were preserved. Implanted scaffolds were tolerated in vivo, with acceptable inflammation, remodeling, and anti-donor antibody formation. Seeding experiments demonstrated cell engraftment and viability.Conclusions: Vascularized and complex auricular scaffolds can be obtained from human source to provide a platform for further functional auricular tissue engineered constructs, hence providing an ideal road to the vascularized composite tissue engineering approach. Statement of SignificanceThe ear is emblematic in the biofabrication of tissues and organs. Current regenerative medicine strategies, with matrix from donor tissues or 3D-printed, didn’t reach any application for reconstruction, because critically missing a vascular tree for perfusion and transplantation. We previously described the production of vascularized and cell-compatible scaffolds, from porcine ear grafts. In this study, we ---- applied findings directly to human auricles harvested from postmortem donors, providing a perfusable matrix that retains the ear’s original complexity and hosts new viable cells after seeding. This approach unlocks the ability to achieve an auricular tissue engineering approach, associated with possible clinical translation.

Repair of Tympanic Membrane Perforations with Customized Bioprinted Ear Grafts Using Chinchilla Models.

The goal of this work is to develop an innovative method that combines bioprinting and endoscopic imaging to repair tympanic membrane perforations (TMPs). TMPs are a serious health issue because they can lead to both conductive hearing loss and repeated otitis media. TMPs occur in 3-5% of cases after ear tube placement, as well as in cases of acute otitis media (the second most common infection in pediatrics), chronic otitis media with or without cholesteatoma, or as a result of barotrauma to the ear. About 55,000 tympanoplasties, the surgery performed to reconstruct TMPs, are performed every year, and the commonly used cartilage grafting technique has a success rate between 43% and 100%. This wide variability in successful tympanoplasty indicates that the current approach relies heavily on the skill of the surgeon to carve the shield graft into the shape of the TMP, which can be extremely difficult because of the perforation's irregular shape. To this end, we hypothesized that patient specific acellular grafts can be bioprinted to repair TMPs. In vitro data demonstrated that our approach resulted in excellent wound healing responses (e.g., cell invasion and proliferations) using our bioprinted gelatin methacrylate constructs. Based on these results, we then bioprinted customized acellular grafts to treat TMP based on endoscopic imaging of the perforation and demonstrated improved TMP healing in a chinchilla study. These ear graft techniques could transform clinical practice by eliminating the need for hand-carved grafts. To our knowledge, this is the first proof of concept of using bioprinting and endoscopic imaging to fabricate customized grafts to treat tissue perforations. This technology could be transferred to other medical pathologies and be used to rapidly scan internal organs such as intestines for microperforations, brain covering (Dura mater) for determination of sites of potential cerebrospinal fluid leaks, and vascular systems to determine arterial wall damage before aneurysm rupture in strokes.

Single-Artery Human Ear Graft Procurement: A Simplified Approach.

Therapeutic, V.

Alternative technique for tip support in secondary rhinoplasty

Re-establishing nasal tip projection is one of the main objectives in secondary rhinoplasty. The columellar strut is used as a basic element for support and the septal cartilage graft as the first choice for reconstruction. Nevertheless, the septal cartilage is often missing in this category of patient because of previous surgery, obliging the surgeon to seek a safe, effective, and versatile alternative. We describe a simple procedure to increase the strength of an autologous ear graft cartilage to be used as a columellar strut in patients having secondary rhinoplasty. We removed a 3.5 x 1.5-cm auricular concha graft through a postauricular approach, leaving the perichondrium on the posterior surface and trimming it on the helical crus. Later, we made a cylinder-shaped structure to be used as a columellar strut graft in patients in whom the septum was absent. We used the open rhinoplasty technique, applying the basic principles of secondary rhinoplasty, in all of the patients. Between February 2002 and June 2006, we used this technique in 13 patients ranging in age from 19 to 52 years who required revision rhinoplasty. The clinical follow-up period ranged from 4 to 48 months. Five of the patients experienced minor complications; nevertheless, all were satisfied with the postoperative results. The auricular cartilage struts constructed using this method were strong enough to enhance tip support and projection, with satisfactory results assessed by both the patients and our team.

Effect of hyperbaric oxygen on survival of the composite ear graft in rats.

In this study the authors set out to determine whether postoperative hyperbaric oxygen (HBO) therapy increases the survival rate of the composite graft in the rat ear model. A composite graft (1 x 0.5 cm2) that included skin, subcutaneous tissue, and cartilage was created from the left ear, and was transferred onto the posterior auricular site of the right ear. The animals were divided into two groups: a control group (N = 10) and an experimental group receiving HBO (N = 10). The experimental group was given HBO immediately following reattachment for 4 hours, and then for 6 hours each day for 5 days (2 atm). The results showed the average ear flap survival area in the experimental group was 82%, and it was 26.5% in the control group (p < 0.01). Histology demonstrated the existence of neovascularization in the experimental group. We have concluded that postoperative HBO therapy increases the survival of the rat ear composite graft, and that the effect of this therapy is influenced by the magnitude (size and thickness) of the graft.

Surgical technique for vascularized ear transplantation in mice.

Traditionally, the mouse nonvascularized skin graft has been widely used in organ transplant research. There are, however, several limitations with this model, the main one being the different immune response of vascularized vs. nonvascularized grafts. We have recently developed a vascularized, orthotopic ear transplant model in mice. This model has several advantages that make it a useful tool to study many aspects of transplantation. The donor operation consists of harvesting the ear with intact arterial and venous pedicles. The arterial pedicle is dissected down to the common carotid artery with ligation of all branches except the auricular artery. The venous pedicle is based on the jugular vein with preservation of the auricular veins draining into the posterior facial vein. In the subsequent recipient operation, the graft is transplanted into an orthotopic position using the common carotid artery for arterial inflow and the jugular vein for venous outflow. We performed 16 such transplants (6 isografts, 5 allografts, and 5 xenografts), with a success rate of 94% (15/16). The donor operation time was 1.5 hours and the recipient operation time was 2.5 hours. The total time for anastamosis was 45 +/- 5 minutes. Serial biopsies were obtained on days 3, 5, and 7, and correlated with gross findings. In summary, this study illustrates that it is technically possible to transplant a mouse ear graft. The main advantage of this model is that it is a vascularized graft that can be visibly observed and easily biopsied, thus allowing for good correlation between gross and histological findings after transplantation. We plan to use this model further to study in detail the rejection patterns in an allograft and xenograft setting.

Bilateral cleft lip reconstruction.

Over a period of 8 years 140 bilateral cleft lips were operated using a muscle-repositioning banked fork-flap cheiloplasty. The use of buccal mucosal flaps in the intercartilaginous incision is helpful to decrease scarring and contracture by facilitating alar cartilage repositioning and wound closure without tension. Adding mucosa from the inferior turbinate makes complete wound closure relatively easy without tension. A lateral lip orbicularis muscle flap with white skin roll and vermilion is recommended for reconstruction of the Cupid's bow. Muscle continuity by freeing the muscle in one sheet and repositioning in front of the premaxilla with creation of a buccal alveolar sulcus is stressed to prevent the necessity of reentering the lip in a second procedure. The elongation of the columella is done at 1 to 6 years of age by advancing nasal floor tissue onto the columella and repositioning the alar cartilages superiorly and medially. When nasal floor tissue is inadequate, columellar lengthening is done by the use of a composite free ear graft.