|Year : 2015 | Volume
| Issue : 1 | Page : 47-50
Microtia reconstruction with irradiated homograft costal cartilage: A preliminary report
Alireza Karimi Yazdi, Amin Amali, Farzad Firouzi
Department of ENT, Imam Khomeini Complex, Tehran University of Medical Sciences, Tehran, Iran
|Date of Web Publication||10-Mar-2015|
Dr. Farzad Firouzi
Department of ENT, Imam Khomeini Complex, Bagherkhan Avenue, Chamran Highway, Tehran
Source of Support: None, Conflict of Interest: None
Background: Reconstruction of microtia is a challenging issue in otology. Autogenous costochondral reconstruction is the most widely accepted approach. However, it is time-consuming and has some limitations. Irradiated homograft costal cartilage has been proposed as a suitable alternative. In the present study, we represent our experience with this approach. Patients and Methods: A total of 19 ears were treated with irradiated homograft costal cartilage prepared from 18 to 40 years old cadaver under a standardized processing method. The reconstruction was achieved a two-stage procedure with at least 3 months interval. Results: The study population included 9 (56.25%) males and 7 (43.75%) females with the mean age of 13.7 ± 5.1 years. Microtia was bilateral in 3, right-sided in 8 and left-sided in 5 subjects. Averagely, subjects were followed for 36.0 ± 9.9 months during which none of the cases showed cartilage resorption. Short-term and long-term complications were negligible. Totally, 90% of subjects were satisfied with the procedure. Conclusion: Irradiated homograft costal cartilage resulted in relatively high satisfaction and low complication rates for auricular reconstruction. Esthetic appearances of the reconstructed auricle were acceptable. The advantages of this approach are the elimination of additional incisions for graft harvesting and donor-site morbidity.
Keywords: Homograft, Irradiation, Microtia, Reconstruction
|How to cite this article:|
Yazdi AK, Amali A, Firouzi F. Microtia reconstruction with irradiated homograft costal cartilage: A preliminary report. Indian J Otol 2015;21:47-50
|How to cite this URL:|
Yazdi AK, Amali A, Firouzi F. Microtia reconstruction with irradiated homograft costal cartilage: A preliminary report. Indian J Otol [serial online] 2015 [cited 2018 Nov 20];21:47-50. Available from: http://www.indianjotol.org/text.asp?2015/21/1/47/152863
| Introduction|| |
Microtia is the abnormal development of the external ear that results in a malformed auricle. The deformity can range from mild distortion of the anatomic landmarks to the complete absence of the ear. Microtia is unilateral more often than bilateral (occurring at a ratio of 4:1), preferentially affects males and the right-side, and occurs in 1 in 7000-8000 live births. 
Reconstruction of microtia represents one of the most challenging issues in otology. It is a complex and labor-intensive process that requires careful preoperative planning, surgical skill, and artistry. A variety of surgical strategies has been proposed for the reconstruction of the external ear among which autogenous costochondral reconstruction found more popularity. The use of costal cartilage in auricular reconstruction was pioneered by Tanzer and accomplished by others.  This technique requires 3-4 stages, each separated by 2-6 months, beginning when the patients is approximately 6-8 years old since the ear reaches 95% of its adult size by the age of 5 years.  However, this approach encompasses some drawbacks. Harvesting of the patient's own costal cartilage may leave the patient with a new scar, keloid, postoperative pain, and the possibility of pleural injuries, pneumothorax, hemothorax, and chest wall deformities. 
Because of the shortcomings and potential problems with autogenous costochondral reconstruction, other alternatives have been proposed such as prosthetic management, either adhesive- or implant-retained, and reconstruction with linear high-density polyethylene (Medpor) surgical implant material. Nevertheless, banked irradiated homograft costal cartilage might be a preferred alternative. , The advantages of this approach are the elimination of additional incisions for graft harvesting and donor-site morbidity as well as a ready availability, semipliable, easily carved, and lower rates of infection and extrusion. ,
Homograft costal cartilage has been employed for reconstruction of facial defects with successful results.  Nevertheless, there are conflicting reports regarding the resorption rate, the resistance to infection and extrusion, and the threat of introducing infections with viruses or prions.  Unfortunately, there are scanty reports regarding the efficacy of homograft and its long-term follow-up in auricular reconstruction. The present study represents our experience with homograft-based auricular reconstruction in a group of Iranian subjects with type III microtia.
| Patients and Methods|| |
A total of 13 subjects with unilateral and three subjects with bilateral microtia were enrolled in our study. Having explained the procedure and how the homograft cartilage is prepared, subjects and/or their parents were requested to fill an informed consent. Then, template was made by carefully tracing the contour of the normal ear in case of unilateral microtia, however, for bilateral defect the template was made with respect to the subject's age and his/her parent ear contour.
Thereafter, the template was transferred to the Iranian transplant bank and desired homograft was created from cartilage block of the sixth, seventh, and eighth ribs and the synchondrosis between the sixth and seventh ribs. Homograft cartilage was prepared from 18 to 40 years old cadaver during the first 24 h following their death under a standardized process as follow. Having removed the cartilage block aseptically, processing was achieved through laminar flow cabinet in clean room facilities in Iranian transplant bank during which extra tissues and perichondrium were dissected, and the cartilage was harvested as desired. Then, the harvested cartilage was soaked in ethanol 70° for 4 h and washed with normal saline thereafter. The final block was packed and treated with gamma irradiation (25 kGy) and stored in a sealed, sterile container at −86°C.
In the operation room, the container was opened aseptically. Prior to sculpting a graft, all perichondrial remnants, and other possible cellular components were removed from the graft's outer surface, to prevent "perichondrial memory" from causing warping. The rib graft was examined in all dimensions to determine the best orientation for carving that will produce the straight grafts.
The following exclusion criteria were applied at baseline for cadaver: Active infective process or collagen vascular disorder before death, positive viral markers (hepatitis-B surface antigen, hepatitis C virus antibodies [Ab], HIV-Ab), long-term corticosteroid use, history of drug abuse, history of malignancy, previous xenograft receivers, and use of hypophyseal-derived drugs. Meanwhile, cadaver first degree relatives were requested to complete an informed consent as well.
Homograft-based microtia reconstruction is a two-stage procedure. The first stage was achieved by shaping of the harvested homograft costal cartilage. Then an incision was made in the area of deformity behind the planned area of cartilage graft. The rudimentary cartilage segment was meticulously removed, and the recipient pocket was elevated in a subcutaneous plane to create adequate space for shaped costal cartilage. Shaped costal cartilage was placed in dissected subcutaneous area. Finally, a small round suction drain was applied to the framework for better adhesion of the skin into the designed furrows and curves in the auricle and covered by adequate dressings.
Patients were admitted for pain control and intravenous antibiotics. The ear drain was removed on day 4 th or 5 th while the ear dressing was removed on day 7 th , postoperatively. Meanwhile, the vascularity of the skin overlying the graft and the overall condition of the graft was inspected on a regular basis for 3 months.
The second-stage was achieved 3-6 months after the first stage. This stage was performed in the following steps: (1) Postauricular incision around the helical rim, (2) dissection of implanted cartilage from its surroundings with sparing of the connective tissue capsule, (3) designing a transposition flap to move a rather vertically oriented lobule to the tail of the framework in a correct position, (4) fish-mouth full-thickness incision of shoulder skin and primarily closure of the donor-site, (5) repair of postauricular sulcus using the prepared skin graft, and (6) advancement of postauricular skin into the postauricular sulcus for covering of the remained exposed area. Then, patients were visited weekly during the first postoperative month and monthly thereafter during the follow-up period.
Results are expressed as mean ± standard deviation for continuous variables unless otherwise stated. Differences between groups were analyzed using Student's unpaired t-test. Qualitative data were compared using χ2 or Fisher's exact test, when appropriate. Associated P values were calculated and a 5% significance threshold was adopted. All statistical analyses were achieved using SPSS software (SPSS version 13.0, SPSS Inc., Chicago, IL, USA).
| Results|| |
Study population included 9 (56.25%) males and 7 (43.75%) females with the mean age of 13.7 ± 5.1 years (a range, 6-21 years). Microtia was bilateral in 3, right-sided in 8 and left-sided in 5 subjects. Hence, 19 ears were reconstructed with a homograft cartilage. None of the patients revealed genetic disorder during preoperative evaluation. However, micrognathia was detected in one.
Preoperative audiometric analysis demonstrated hearing loss of 60, 55 and 50 dB in 8 (42.1%), 6 (31.6%), and 5 (26.3%) subjects, respectively. Averagely, subjects were followed for 36.0 ± 9.9 months (a range, 12-46 months) during which none of the cases showed cartilage resorption however the right-sided homograft cartilage extrusion was detected in one subject. He was a 16-year-old boy presented with bilateral microtia for whom the second-stage surgery was achieved bilaterally and the extrusion was corrected.
Short-term complications (within the first 3 months) were erythema in 38.8% of the operated ears followed by painful swelling in 10.5% and ulceration in 5.3% of ears, however, late complications were noted in two subjects, one complained of homograft cartilage extrusion (as mentioned earlier) and the other suffered from infection, both of whom were managed accordingly.
The mean width and length of the reconstructed ears were 4.02 ± 0.21 and 4.79 ± 0.34 cm, respectively. Although in cases of unilateral microtia the dimensions of the reconstructed ears were significantly differed from the normal ears (4.20 ± 0.16 and 4.99 ± 0.32 cm, respectively), the general appearance was within the acceptable range.
Finally, subjects' satisfaction was evaluated, and 32% were fully satisfied compared with 10% who were unsatisfied. A total of 58% were more or less satisfied with their appearance.
| Discussion|| |
Managing patients with microtia can be a rewarding experience for the surgeon. Indeed, each ear deformity is unique; hence managing of these patients is a humbling, challenging and perceptually stimulating achievement. In the present study, we demonstrate our experience with 19 years reconstructed with homograft costal cartilage in a two-stage approach. Subjects were followed 12-46 months during which none of the cases were complicated with cartilage resorption. Short- and long-term complications were well managed accordingly, and the overall satisfaction rate was roughly high. Although the differences in dimensions of the harvested cartilages did reach a statistically significant level, the esthetic appearance was accepted not only by the surgeon but also by the subjects.
Microtia repair using autogenous cartilage is the gold standard of surgical reconstruction. As mentioned earlier, this technique was developed by Tanzer and accomplished by others and consists of a multistage operative technique. , Chest wall donor-site complications are the main limitations of autograft reconstruction procedures. ,, Pneumothorax and atelectasis occur rarely, but considerable pain or discomfort is the most important complication in immediate postoperative period. ,, Delayed scarring and chest wall deformity occurred in considerable number of operated patients.  Hypertrophic scar is another important complication.  The harvest procedure alone adds to operative and anesthetic time and expense. Keep in mind these shortcomings, homograft could be a suitable alternative.
Homografts have most of the advantages of the autologous graft while they could not be complicated by donor-site morbidity. Indeed, homograft cartilage material is readily available in large quantity and is easily sculptured while it poses lower rates of infection and extrusion. Meanwhile, the harvested cartilage is remarkably well-tolerated by host tissue, eliciting minimal antigenic response partly due to the technique of processing, namely irradiation. , The use of homologous rib cartilage may back to 1941, when Straith and Slaughter developed the usage of this technique in reconstructing 100 facial contouring cases with a very high success rate.  Kridel and Konior presented their experience with 122 rhinoplastic procedures in which 306 irradiated homograft of costal cartilage were used. During their follow-up (1-84 months) complete or partial resorption was noted for 4 grafts.  Similarly, Murakami et al. explained how they reconstructed a series of 18 patients with saddle nose deformities with articulated irradiated rib cartilage. Follow-up ranged from 1 to 6 years (mean, 2.8 years), and none of the treated subjects showed infection, extrusion, or noticeable resorption.  Conversely, Burke et al. followed 177 cases managed with irradiated homograft rib cartilage. A total of 13 patients were followed for 5-10 years, of whom 4 had severe to complete loss of graft volume (51-100% resorption), whereas 2 of 3 patients (66%) with follow-up of > 10 years showed this volume reduction.  They also demonstrated the long-term outcome of irradiated homograft rib cartilage for auricular reconstruction and found a surprisingly high resorption rate (71%).  Finally, in 2002, Clark and Cook successfully employed irradiated homograft rib cartilage for nasal reconstruction with only one case of warping. 
Cartilage resorption is a challenging pitfall in irradiated homograft cartilage, however, the resorption phenomena is usually associated with a loss of structural support rather than by a loss of volume, a fact that could be promising in auricular reconstruction. Moreover, warping could also alter the final outcome. Postoperative homograft infection is negligible and easily managed by intravenous antibiotics and drainage. In general, the results of homograft costal cartilage are influenced by a variety of factors, including the processing technique of harvested cartilage, the site of the graft (possibly poorer results in auricle), the predisposing health condition of patients, the length of the follow-up period (longer follow-up is associated with higher resorption rate), the surgical techniques, the method of dressing, and of course the postoperative care. ,,
| Conclusion|| |
In our setting, irradiated homograft costal cartilage resulted in relatively high satisfaction and low complication rates for auricular reconstruction. Esthetic appearances of the reconstructed auricle were acceptable. The advantages of this approach are the elimination of additional incisions for graft harvesting and donor-site morbidity.
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