Subfascial expansion and expanded two-flap method for microtia reconstruction

This article presents an improved two-flap method for microtia reconstruction. In the first stage of this method, a tissue expander is inserted in the mastoid region through a subfascial pocket, after which the overlying fascia and skin are expanded simultaneously with saline infusion for about 5 months. In the second stage, the expanded fascial and skin layers are split and prepared as anteriorly based skin and fascial flaps defined by their vascularity. An erect, three-dimensional, contour-accentuated ear framework fabricated with autogenous rib cartilage is inserted between the two flaps. The anteroauricular surface of the framework is draped with the thin, expanded skin, and the postauricular surface is draped with the thin, expanded fascia and overlying grafted skin. In the third stage, remnant auricular cartilage is removed and the crus helicis, tragus, intertragic notch, conchal floor, and a hollow mimicking the external auditory meatus are shaped. In this study, 146 microtias were reconstructed consecutively using the improved two-flap method. The final results were promising--major complications were minimal and most patients showed consistently favorable aesthetic results. This method married a two-flap procedure with a gradual tissue expansion, conveniently exploiting the advantages of both methods, but without the disadvantages.     

Conchal transposition flap for postburn ear deformities

Severe thermal injuries to the external ear often lead to extensive loss of peripheral structures such as helix and lobule but frequently spare the more central parts of the ear, even though they may be grossly deformed by scar contracture. The use of spared conchal structures as a transposition flap in combination with remodeling of the residual auricle and release of surrounding scar when indicated has been a useful technique in the reconstruction of a frequently occurring type of postburn ear deformity. Twenty-four ears have been reconstructed in 18 patients over the past 5 years using a conchal transposition flap. The residual concha with its overlying skin can be transposed superiorly, based on a very narrow pedicle in the area of the crus helicis. The raw central area remaining is then resurfaced with a split-thickness skin graft. This technique maximally utilizes the unique remaining auricular elements and can provide a satisfactory reconstruction in selected patients without resorting to more complex and extensive procedures. There have been no significant complications in this series, and patient acceptance of the results has been excellent.     

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.     

先天性小耳畸形手术治疗的研究进展

先天性小耳畸形是发病率较高的头面部畸形之一,常为耳廓及中耳腔同时存在,内耳发育不良相对少见,这一疾病所致的缺陷不仅影响到患者的容貌,更重要的是导致患者听觉功能的障碍,严重影响到患者的日常工作学习和生活。部分患者还伴有或多或少的心理影响,这在双侧小耳畸形的患者中更多见。手术是其主要的治疗方法,要求不仅重建外形正常的耳廓,同时还拥有正常或接近正常的听力。外耳廓再造和听力重建手术不仅使先天性小耳畸形患者的耳部外观明显改善,还能使其听觉功能进一步提高。本文主要综述了先天性小耳畸形的病因和流行病学、分类、手术时机和方式的选择、听力重建、耳廓再造的方法及组织工程学耳再造技术,重点介绍了耳廓再造材料的选择及手术注意点,以期为先天性小耳畸形的临床治疗提供更多理论依据。     

A new method utilizing the bipedicle flap for reconstruction of the external auditory canal in microtia

A new technique using the bipedicle flap for reconstruction of microtia is described. This technique makes possible construction of a well-shaped new auricle in the presence of scar formation because of tympanoplasty in which the external auditory canal has been created posteriorly.     

Microtia reconstruction: does the cartilage framework grow?

The use of free rib cartilage ear frameworks in unilateral microtia reconstruction has prompted much discussion about their potential for growth. The senior author has reconstructed ear frameworks in 132 microtia patients, most of whom were under 3 years of age when surgery was initiated. Of this group, 29 were assessed for ear growth through comparison of the lead-plate model of the original normal ear to the normal ear growth and the reconstructed ear framework after a period of at least 2 years. Similarly, 14 reconstructed ears were compared to 14 normal ears at least 2 years after reconstruction. The perimeters of tracings made from the original lead plates and of tracings of normal and reconstructed ears were determined by image analysis techniques. The results demonstrated no significant difference in growth between normal ears and reconstructed ear frameworks after an interval of at least 2.5 years. Therefore, the reconstructed ear is growing at a rate similar to that of the normal ear.     

Framework growth after reconstruction for microtia: is it real and what are the implications?

Historically, fashioning an auricle for a patient born with microtia has been one of the most challenging endeavors in the repertoire of reconstructive surgeons. Despite many ideas advanced on types of materials for the auricular framework, the hands-down favorite and today's medium of choice is autogenous costal cartilage. A subject that remains up for discussion, however, is the question of growth potential in these cartilaginous frameworks. Popularization of the surgical technique for auricular reconstruction has led to much bandying about of opinions on this very important question of growth. Although previous reports allude to the probability of an increase in auricular size after reconstruction, this report is the first to document changes in auricular size with measurements taken directly from patients at the time of graft implantation and during subsequent long-term follow-up. The goals of this study are to define the behavior of the autogenous framework after reconstruction of the microtic auricle. This information serves to clarify the issue of proper framework sizing and to make evident the early age at which reconstruction can begin.The records of patients who underwent costal cartilage auricular reconstruction for grade III microtia between 1990 and 1996 were reviewed, and a cohort of 10 patients was chosen for inclusion based on availability for follow-up and lack of any interval modifications of their cartilaginous framework. The average age was 6.7 years, and the average time interval from initial reconstruction to follow-up was 3.2 years. Measurements of the auricular framework height and width were taken at implantation and at time of final follow-up, and measurements were recorded of the normal ears of patients with unilateral microtia. The mean auricular size was examined for significance of interval change using the two-sample Student's t tests, assuming unequal variances.The results revealed an average height increase of 5 mm (10.4 percent) in the study population. Auricular width changes averaged 2.75 mm (7.02 percent). Growth trends revealed a distinct tendency toward increasing auricular framework size over time, with slowing as patients neared adolescence. Comparison of the reconstructed auricle to the normal ear of each patient with unilateral microtia showed that the reconstructed ear paralleled the growth of the normal side, with no statistically significant differences in height or width at follow-up.This is the first report of auricular framework behavior based on patients having direct measurement of their framework initially and in long-term follow-up. This patient sample underscores a clear pattern of growth in the reconstructed auricles paralleling that of the normal ears. The implications of this finding are important in that the initial oversizing of the framework becomes unnecessary. Moreover, the decision as to age at initial reconstruction is not affected by anticipated growth rates.     

A problem-oriented and segmental open approach to alar cartilage losses and alar length discrepancies

Alar cartilage losses and alar length discrepancies present problems in nasal tip support, contour, and symmetry. The true extent of the cartilage defect is often not apparent until the time of surgery. This article examines a problem-oriented and segmental open approach to such deformities. It is based on the size of the defect, its location within the dome and lateral crus, and the presence or absence of alar collapse. The defects are classified as major when there is a total or near total loss of the lateral crus, moderate when more than 5 mm is involved, and minor when less than 5 mm is affected. In major defects, a segmental reconstruction of the nasal tip cartilages is undertaken. It consists of a septal graft for columellar support and a conchal shield graft and umbrella graft for nasal tip contour. The whole length of the lateral crus is not reconstructed unless alar collapse is present. In moderate cartilage defects, usually seen laterally in secondary rhinoplasties, the remaining central dome segments are remodeled with shaping sutures. Moderate cartilage length discrepancies, as seen in unilateral cleft lip noses, are equalized through reversed alar rotations. The short crus is rotated laterally, taking length from the medial crus, and the long crus is rotated medially, with the excess advanced into the medial crural footplate. Additional shortening of the long crus can be achieved through cartilage division and advancement. The balanced alar units are then raised with tip projection-vector sutures, and onlay grafts are added if required. In minor cartilage losses, symmetry is usually obtained by shortening the opposite uninjured crus. A total of 33 patients are examined in this review. The average follow-up is 14 months. An improvement in nasal tip shape and support was achieved in all patients.     

Reconstruction of microtia with a contour-accentuated framework and supplemental coverage

A new method of assembling the framework of the ear with overaccentuated auricular contour is presented. In order to achieve the primary objective of the contour-accentuated framework, any shortage of skin coverage resulting from the increased surface area of the framework is supplied by the resurfaced temporoparietal fascial flap. This is done in 7 cases of microtia reconstruction. The procedure is beneficial for restoring clearly defined auricular relief in ear reconstruction.     

Auricular reconstruction for microtia: Part II. Surgical techniques

Reconstruction of the microtic ear represents one of the most demanding challenges in reconstructive surgery. In this review the two most commonly used techniques for ear reconstruction, the Brent and Nagata techniques, are addressed in detail. Unique to this endeavor, the originator of each technique has been allowed to submit representative case material and to address the pros and cons of the other's technique. What follows is a detailed, insightful overview of microtia reconstruction, as a state of the art. The review then details commonly encountered problems in ear reconstruction and pertinent technical points. Finally, a glimpse into the future is offered with an accounting of the advances made in tissue engineering as this technology applies to auricular reconstruction.     

Genome-Wide Linkage Study Suggests a Susceptibility Locus for Isolated Bilateral Microtia on 4p15.32–4p16.2

Microtia is a congenital deformity where the external ear is underdeveloped. Genetic investigations have identified many susceptibility genes of microtia-related syndromes. However, no causal genes were reported for isolated microtia, the main form of microtia. We conducted a genome-wide linkage analysis on a 5-generation Chinese pedigree with isolated bilateral microtia. We identified a suggestive linkage locus on 4p15.32–4p16.2 with parametric LOD score of 2.70 and nonparametric linkage score (Zmean) of 12.28 (simulated occurrence per genome scan equal to 0.46 and 0.47, respectively). Haplotype reconstruction analysis of the 4p15.32–4p16.2 region further confined the linkage signal to a 10-Mb segment located between rs12505562 and rs12649803 (9.65–30.24 cM; 5.54–15.58 Mb). Various human organ developmental genes reside in this 10-Mb susceptibility region, such as EVC, EVC2, SLC2A9, NKX3-2, and HMX1. The coding regions of three genes, EVC known for cartilage development and NKX3-2, HMX1 involved in microtia, were selected for sequencing with 5 individuals from the pedigree. Of the 38 identified sequence variants, none segregates along with the disease phenotype. Other genes or DNA sequences of the 10-Mb region warrant for further investigation. In conclusion, we report a susceptibility locus of isolated microtia, and this finding will encourage future studies on the genetic basis of ear deformity.     

Autogenous rib cartilage reconstruction of congenital ear defects: report of 110 cases with Brent's technique

The purpose of this study was to confirm the feasibility of Brent's technique, which was adopted for the treatment of the patients in this series. The author reports his experience with the successful treatment of 110 consecutive patients born with unilateral 95 (86.4 percent) and bilateral 15 (13.6 percent) microtia. The main stages of the reconstruction process are described, from the initial consultation to completion of treatment: reconstruction with sculpted rib cartilage graft, lobule transposition, tragus construction, and construction of the retroauricular sulcus. Minor modifications of Brent's technique for the last surgical stage are described. The author stresses use of autogenous rib cartilage as basic reconstruction material and emphasizes meticulous carving and assembling of frameworks, for which a balanced blend of structural firmness and aesthetic smoothness is essential. The author also describes complications and their management; cases of abandonment of treatment before completion; and difficulties encountered for long-term follow-up. Specially encouraging was the low proportion of short- and long-term complications: one case of hematoma (0.91 percent), one case of infection, two cases of partial skin loss (1.82 percent), and three cases of hypertrophic scars (2.73 percent). Older patients were more prone to abandon treatment before completion of all surgical stages (p = 0.000243) in this series, and this tendency occurred more frequently during the author's early experience in treating microtia patients. Despite the difficulty of the task, this series corroborates the versatility and feasibility of the technique in different geographical areas and population groups.     

Two sequence classes of kinetoplastid 5S ribosomal RNA gene revealed among bodonid spliced leader RNA gene arrays

The spliced leader RNA genes of Bodo saltans, Cryptobia helicis and Dimastigella trypaniformis were analyzed as molecular markers for additional taxa within the suborder Bodonina. The non-transcribed spacer regions were distinctive for each organism, and 5S rRNA genes were present in Bodo and Dimastigella but not in C. helicis. Two sequence classes of 5S rRNA were evident from analysis of the bodonid genes. The two classes of 5S rRNA genes were found in other Kinetoplastids independent of co-localization with the spliced leader RNA gene.     

A single-stage two-flap method of total ear reconstruction

A single-stage two-flap method of total ear reconstruction in congenital microtia is reported. This method was derived from the one-stage reconstruction described by Song and Song. Two flaps defined by vascular basis were elevated on the mastoid area: the superficial skin flap supplied mainly by subcutaneous pedicled arteriole perforators from the posterior auricular artery and the deeper axial-pattern fascial flap including the posterior auricular artery itself. The ear framework, exaggeratedly carved using autologous rib cartilage, could be inserted easily between the two flaps, simultaneously producing the auriculocephalic angle and the conchal wall. Intraoperative expansion of the skin flap and postoperative external ear molding also were performed to create aesthetically pleasing ears.     

Management of the hairline using a local flap in total reconstruction for microtia

In cases of microtia with a low hairline, the manner in which hair is removed from the reconstructed auricle must be taken into consideration. This is one of the most common but difficult problems with reconstruction for microtia. The authors describe a new technique that uses a simple regional flap to resolve this problem. The hair-bearing skin in the estimated auricular region and its covering are removed using a local flap from the hairless mastoid region. This is done in the first stage of auricular reconstruction, the costal cartilage grafting is done in the second stage, and elevation of the auricle is done in the last stage. In 38 auricles of 36 patients who were treated from 1993 to 1995, eight auricles of eight patients were treated with this technique. In all cases, the hairless flap healed well, without vascular stasis or skin necrosis. In addition, no complications from using this technique occurred in the later stages of auricular reconstruction. With this technique, the skin of the flap provides a good texture and color match to the auricle. In addition, the skin of the flap has good elasticity for the cutaneous pocket for cartilage grafting. The harvested area of the flap can be hidden behind the reconstructed auricle. The authors initially wondered whether the marginal scar of the transposed flap's position in the auricle would be conspicuous. However, all of the scar became inconspicuous because it was positioned in the scaphoid fossa.     

Genome-wide association study shows that microtia in Altay sheep is caused by a 76 bp duplication of HMX1

Microtia is a congenital malformation of the external ear that can be observed in many species including sheep. However, the genetic basis of microtia still remains unclear. Here, a GWAS was conducted to investigate the genetic basis underlying microtia. A total of 55 samples from 26 microtia and 29 normal animals were genotyped with Illumina OvineHD BeadChip. The strongest significant SNP was identified on OAR6, approximating the evolutionarily conserved region of the HMX1 gene, which is related to congenital malformations of the external ear in other species such as cattle and rats. Sequencing an evolutionarily conserved region surrounding HMX1 revealed a duplication of 76 bp, which is concordant with microtia, suggesting a dominant inheritance mode. Identification of this causal mutation in the HMX1 gene indicates the role of this particular gene in the development of the external ear and provides a genetic marker for selection against microtia.     

先天性小耳畸形危险因素研究进展

先天性小耳畸形即小耳症,主要指耳廓、外耳道的畸形、听力损害等,少数患者合并外耳道闭锁、中耳及面部畸形。尽管先天性小耳畸形的发病机制尚未完全明确,但已有研究证实其发生可能与环境和遗传因素有关。因此,对于相关流行病学调查的相关因素与风险因素的研究与规避,并以此指导开展针对性防治工作显得尤为重要。本文将从流行病学特征及相关危险因素两个方面对于病因学进行探讨与总结。     

先天性小耳畸形耳廓再造及 BAHA 安装一期手术的研究

目的:研究通过多孔高密度聚乙烯(MEDPOR)支架植入,一期完成全耳廓再造+骨锚式助听器BAHA安装,术后观察耳廓外形变化,听力恢复程度,了解一期联合手术的初期临床疗效。方法:对前来就诊的先天性小耳畸形患者,术前进行外形,听力,影像学评估,对于Jahrsdoerfer评分小于及等于5分,行多孔高密度聚乙烯(MEDPOR)支架植入,一期耳廓再造术+骨锚式助听器(BAHA)植入术。术后两周起,定期观察患者耳廓改善及听力恢复情况,了解手术的治疗效果。结果:临床病例3例,术后两周起开始随访,再造耳廓外形逼真,无支架外露;所有患者听力均获得较大程度改善。结论:该方法具有疗程短、并发症少、临床效果佳等优点。该方法切实可行,可用于临床推广应用。     

Correction of congenital microtia using the tissue expander

We attempted auricular reconstruction using Radovan-type inflatable silicone expanders in six children and one adult, with the complete hypoplastic, the conchal remnant, and constricted type of microtia. Ear frameworks, including the helix, anthelix, concha, and tragus, were prepared using autologous rib cartilage. Based on the surface area of the normal adult auricle, the silicone expander was tentatively shaped and sized into a rotated semiellipse and expanded with 70 cc saline. Auricular reconstruction on the framework was completed at the time of insertion in four of the seven patients, requiring no elevation of the ear. The reconstructed auricle was satisfactory in both color and texture and had nearly normal sensation. Mild complications were noted in three of the seven patients. However, no resorption of the inserted rib cartilage has been observed 14 months to 2 years and 5 months after the operation. Slight shrinkage of the expanded skin was noted in each patient.     

Pankinetoplast DNA structure in a primitive bodonid flagellate, Cryptobia helicis.

The mitochondrial DNA (mtDNA) of a primitive kinetoplastid flagellate Cryptobia helicis is composed of 4.2 kb minicircles and 43 kb maxicircles. 85% and 6% of the minicircles are in the form of supercoiled (SC) and relaxed (OC) monomers, respectively. The remaining minicircles (9%) constitute catenated oligomers composed of both the SC and OC molecules. Minicircles contain bent helix and sequences homologous to the minicircle conserved sequence blocks. Maxicircles encode typical mitochondrial genes and are not catenated. The mtDNA, which we describe with the term 'pankinetoplast DNA', is spread throughout the mitochondrial lumen, where it is associated with multiple electron-lucent loci. There are approximately 8400 minicircles per pankinetoplast-mitochondrion, with the pan-kDNA representing approximately 36% of the total cellular DNA. Based on the similarity of the C.helicis minicircles to plasmids, we present a theory on the formation of the kDNA network.