The external ear: More attention to detail may aid syndrome diagnosis and contribute answers to embryological questions

Diagnosis and Prevalence of Prominent Lobules in Otoplasty: Analysis of 120 Patients with Prominent Ears

BACKGROUND

The prominence of the ear lobule is considered an anomaly of secondary importance and receives correspondingly less attention in literature. We reviewed a case series of otoplasty patients and analyzed the prevalence of lobule prominence.

METHODS

Records of otoplasties between 2007 and 2013 were reviewed. Inclusion criteria were: (1) primary otoplasties; (2) prominence of both ears; and (3) otoplasties conducted by the main author. Patients were divided into two groups: (1) A general group (GG) containing all the patients, and (2) a lobule correction group (LG)-a subgroup of GG containing only the patients who needed lobule correction.

RESULTS

From a total of 291 patients, 120 patients were included in GG and 27 patients in LG. There was no statistical difference between groups GG and LG in terms of age and gender. Preoperative diagnosis of lobule prominence was correctly established in 14 patients; 13 patients were diagnosed during surgery.

CONCLUSIONS

Lobule prominence should not be underestimated since its diagnosis may be missed in the preoperative period-nearly 50 % in our case. Also its prevalence (22.5 %) is not as infrequent as some may think. Knowledge of lobule correction techniques before surgery is important to avoid less than optimal results in otoplasty.

LEVEL OF EVIDENCE V

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The Role of Skeletal Muscle in External Ear Development: A Mouse Model Histomorphometric Study

Background:

Mechanical stimuli imparted by skeletal muscles play an important role during embryonic development in vertebrates. Little is known whether skeletal muscles are required for normal external ear development.

Methods:

We used Myf5−/−:MyoD−/− (double-mutant) mouse embryos that completely lack skeletal musculature and analyzed the development of the external ear. We concentrated on the external ear because several studies have suggested a muscular cause to various congenital auricular deformities, and middle and inner ear development was previously reported using the same mouse model. Wild-type mouse embryos were used as controls to compare the histomorphometric outcomes.

Results:

Our findings demonstrated an absence of the external auditory meatus, along with an abnormal auricular appearance, in the double-mutant mouse embryos. Specifically, the auricle did not protrude laterally as noted in the wild-type mouse ears. However, histomorphometric measurements were not significantly different between the wild-type and double-mutant mouse ears.

Conclusion:

Overall, our study showed that the development of the mouse external ear is dependent on the presence of skeletal muscles.

Prenatal ultrasound screening for external ear abnormality in the fetuses

Objectives. To investigate the best time of examination and section chosen of routine prenatal ultrasound screening for external ear abnormalities and evaluate the feasibility of examining the fetal external ear with ultrasonography. Methods. From July 2010 until August 2011, 42118 pregnant women with single fetus during 16–40 weeks of pregnancy were enrolled in the study. Fetal auricles and external auditory canal in the second trimester of pregnancy were evaluated by routine color Doppler ultrasound screening and systematic screening. Ultrasound images of fetal external ears were obtained on transverse-incline view at cervical vertebra level and mandible level and on parasagittal view and coronal view at external ear level. Results. Five fetuses had anomalous ears including bilateral malformed auricles with malformed external auditory canal, unilateral deformed external ear, and unilateral microtia. The detection rate of both auricles was negatively correlated with gestational age. Of the 5843 fetuses undergoing a routine ultrasound screening, 5797 (99.21%) had bilateral auricles. Of the 4955 fetuses following systematic screening, all fetuses (100%) had bilateral auricles. The best time for fetal auricles observation with ultrasonography is 20–24 weeks of pregnancy. Conclusions. Detection of external ear abnormalities may assist in the diagnosis of chromosomal abnormalities.

Mouse Hoxa2 mutations provide a model for microtia and auricle duplication

External ear abnormalities are frequent in newborns ranging from microtia to partial auricle duplication. Little is known about the molecular mechanisms orchestrating external ear morphogenesis. In humans, HOXA2 partial loss of function induces a bilateral microtia associated with an abnormal shape of the auricle. In mice, Hoxa2 inactivation at early gestational stages results in external auditory canal (EAC) duplication and absence of the auricle, whereas its late inactivation results in a hypomorphic auricle, mimicking the human HOXA2 mutant condition. By genetic fate mapping we found that the mouse auricle (or pinna) derives from the Hoxa2-expressing neural crest-derived mesenchyme of the second pharyngeal arch, and not from a composite of first and second arch mesenchyme as previously proposed based on morphological observation of human embryos. Moreover, the mouse EAC is entirely lined by Hoxa2-negative first arch mesenchyme and does not develop at the first pharyngeal cleft, as previously assumed. Conditional ectopic Hoxa2 expression in first arch neural crest is sufficient to induce a complete duplication of the pinna and a loss of the EAC, suggesting transformation of the first arch neural crest-derived mesenchyme lining the EAC into an ectopic pinna. Hoxa2 partly controls the morphogenesis of the pinna through the BMP signalling pathway and expression of Eya1, which in humans is involved in branchio-oto-renal syndrome. Thus, Hoxa2 loss- and gain-of-function approaches in mice provide a suitable model to investigate the molecular aetiology of microtia and auricle duplication.

Further characterization of atypical features in auriculocondylar syndrome caused by recessive PLCB4 mutations

Auriculocondylar syndrome (ACS) is a branchial arch syndrome typically inherited in an autosomal dominant fashion. Patients with ACS display the following core symptoms with varying severity: a specific malformation of the external ear, known as a "question mark ear," micrognathia and mandibular condyle hypoplasia. Recently, phospholipase C, β 4 (PLCB4) mutations were identified as the major cause of autosomal dominant ACS, with mutations of the PLCB4 catalytic domain predicted to have a dominant negative effect. In addition, one ACS patient born to related parents harbored a homozygous partial deletion of PLCB4, and presented with ACS plus central apnea and macropenis; these features had not been previously reported in association with ACS. His parents, each with a heterozygous partial PLCB4 deletion, were phenotypically normal, suggesting autosomal recessive inheritance of ACS, with complete loss of function of PLCB4 predicted in the patient. We herein describe two brothers with ACS caused by compound heterozygous splice site mutations in PLCB4. The patients were born to the same unrelated and healthy parents, with each parent harboring one of the mutations, indicating autosomal recessive ACS. Both patients reported here had mixed apneas, gastrointestinal transit defects and macropenis, in addition to typical craniofacial features of ACS. This is the first example of ACS caused by compound heterozygous splice site mutations in PLCB4, the second autosomal recessive case of ACS confirmed by molecular analysis, and strengthens the link between complete loss of function of PLCB4 and extra-craniofacial features.

External ear abnormalities in existing scales for minor physical anomalies: are they enough?

The pattern of external ear abnormalities in patients with schizophrenia and bipolar disorder was studied. Sixty-seven male patients having schizophrenia (n=30) and bipolar disorder (n=37) were examined using a scale constructed for the study. Stepwise logistic regression analysis showed that 'prominent crux of helix' and 'ear lobe crease' could differentiate between schizophrenia and bipolar disorder. These external ear abnormalities need further characterization and consideration for possible inclusion in scales that assess minor physical anomalies.

A prospective study on non-surgical correction of protruding ears: the importance of early treatment

OBJECTIVES

Splinting is an elegant method to correct ear deformities in the newborn. However evidence is lacking on the relation between age and efficacy and duration of the treatment. We prospectively studied these questions on protruding ears in 132 babies.

METHODS

A splint in the scaphal hollow was used in combination with tape (Earbuddies(®)). Treatment continued until the desired shape persisted. Results were judged from photographs and mastoid-helical distance was measured.

RESULTS

In 132 babies 209 ears were treated. Twenty-four patients had no follow-up, 27 stopped therapy for skin irritation and fixation problems. In the remaining patients results were good in 28%, fair in 36%, poor in 36%. Efficacy deteriorates with age; with fair or good results in 66.7% if therapy started before the sixth week. Older children needed to be splinted longer. The anti-helical fold was easier corrected than a deep concha (correction in 69.8% versus 26.8%).

CONCLUSIONS

Considering splinting therapy for protruding ears, a reasonable chance of success can only be offered to parents of children up to six weeks of age. It is favorable if the deformity is mainly due to a flat antihelix.

Detailed assessment of the ear in Cornelia de Lange syndrome: comparison with a control sample using the new dysmorphology guidelines

The literature abounds with reports of malformation syndromes in which human external ears are variously described as dysplastic, abnormal, large/small, low set, typical, or in some way unusual. Rarely is the ear well illustrated or described in meaningful detail. With few exceptions, such as Down syndrome, there is no real understanding of the degree to which ear morphology is affected in a specific syndrome. This paper describes a retrospective attempt to apply the recently published Morphological Definitions of the ear to compare a control sample of convenience with a group of patients with Cornelia de Lange syndrome (CdLS) (all six papers in this issue are available online, open access at http://www3.interscience.wiley.com/journal/121641055/issue). Although this study has a number of limitations, it demonstrates that the method can be successfully applied and is capable of producing data that can be subjected to statistical analysis. The ears of the patients with CdLS were significantly different from the controls over a number of descriptors, the most significant of which included more frequent apparent posterior rotation, a shorter more serpiginous antihelical stem and sharper antihelical to inferior crus angle, a shorter crus helix, a more V-shaped incisura, and a smaller lobe.

Microcephaly, microtia, preauricular tags, choanal atresia and developmental delay in three unrelated patients: a mandibulofacial dysostosis distinct from Treacher Collins syndrome

Treacher Collins syndrome (TCS, OMIM 154500) is a well-defined mandibulofacial dysostosis characterized by symmetric facial anomalies consisting of malar hypoplasia, coloboma of the lower eyelid, dysplastic ears, micrognathia, cleft palate and deafness. Other mandibulofacial dysostoses (MDs) such as Toriello (OMIM 301950), Bauru (OMIM 604830), Hedera-Toriello-Petty (OMIM 608257), and Guion-Almeida (OMIM 610536) syndromes are less well characterized and much rarer. Here we describe three unrelated patients showing clinical features overlapping with TCS, but who in addition have developmental delay, microcephaly and a distinct facial gestalt. Because of the distinct ear anomalies and the hearing loss a HOXA2 mutation was taken into account. CHARGE syndrome was discussed because of ear anomalies, choanal atresia, and developmental delay in our patients. But mutational analyses including sequencing of the TCOF1, the HOXA2, and the CHD7 genes, deletion screening of the TCOF1 gene as well as genomewide array analyses revealed normal results. We suggest that these three patients have a new type of mandibulofacial dysostosis. As all three cases are sporadic and both sexes are affected the pattern of inheritance might be autosomal dominant or autosomal recessive. Identification of additional patients will allow to further delineate the phenotype, to assign the inheritance pattern and to identify the molecular basis.

Age- and sex-related changes in the normal human ear

The objective of this study was to supply information about: (1) normal sex-related dimensions of ears (linear distances and ratios, area); (2) left-right symmetry; and (3) growth changes between childhood and old age. The three-dimensional coordinates of several soft-tissue landmarks on the ears and face were obtained by a non-invasive, computerized electromagnetic digitizer in 497 male and 346 female healthy subjects aged 4-73 years. From the landmarks, paired ear width and length, the relevant ratios, ear areas and angles relative to the facial midline, as well as indices of left-right symmetry, were calculated, and averaged for age and sex. Comparisons were performed by factorial analysis of variance. All ear dimensions were significantly larger in men than in women (p<0.001). A significant effect of age was found (p<0.001), with larger values in older individuals. The ear width-to-length ratio and the sagittal angle of the auricle significantly decreased as a function of age (p<0.001) but without sex-related differences. On average, the three-dimensional position of ears was symmetric, with symmetry coefficients ranging between 92% and 96%. Asymmetry was found in the sagittal angle of the auricle (both sexes), in the ear width-to-length ratio and ear width (men only). Data collected in the present investigation could serve as a data base for the quantitative description of human ear morphology and position during normal growth, development and aging. Forensic applications (evaluations of traumas, craniofacial alterations, teratogenic-induced conditions, facial reconstruction, aging of living and dead persons, personal identification) may also benefit from age- and sex-based data banks.

Elements of morphology: standard terminology for the ear

An international group of clinicians working in the field of dysmorphology has initiated the standardization of terms used to describe human morphology. The goals are to standardize these terms and reach consensus regarding their definitions. In this way, we will increase the utility of descriptions of the human phenotype and facilitate reliable comparisons of findings among patients. Discussions with other workers in dysmorphology and related fields, such as developmental biology and molecular genetics, will become more precise. Here we introduce the anatomy of the ear and define and illustrate the terms that describe the major characteristics of the ear.

Dominantly-inherited lop ears

We describe a four-generation Chinese family that included five members who had an isolated bilateral lop ear anomaly. The presentation suggested a dominant mode of inheritance. The absence of male-to-male transmission does not exclude an X-linked dominant mode of inheritance. Since the phenotypic anomaly of the male proband was no more severe than the affected female members, an autosomal dominant mode of inheritance is most likely.

A new phenotypical variant of intrauterine growth restriction?

OBJECTIVES

A link between intrauterine growth restriction and major adult-onset diseases has been reported. In this study we observed a series of hitherto-unrecognized clinical features in a population of children with intrauterine growth restriction.

PATIENTS AND METHODS

A total of 77 Italian children (aged 9.45 +/- 2.08 years) with antenatally diagnosed intrauterine growth restriction and small-for-gestational-age birth, along with their parents, were examined. The children with intrauterine growth restriction and were small for gestational age were subdivided into 2 groups ("variant" versus control subjects) according to evidence of auricle morphology deviation from normal. The following variables were determined: (1) external ear auricle geometry; (2) function of the posterior communicating arteries of the circle of Willis, as assessed by transcranial Doppler ultrasonography; (3) articular mobility, as assessed by Beighton's 9-point scale; (4) skin softness; and (5) distortion product-evoked otoacoustic emissions.

RESULTS

Intrauterine growth restriction-variant children (n = 27) showed a significant female predominance, a lower proportion of maternal pregnancy-induced hypertension/preeclampsia, and a higher head circumference as compared with intrauterine growth restriction control subjects. Mothers of small-for-gestational-age-variant children showed significantly different auricular geometry parameters as compared with the intrauterine growth restriction controls mothers. An excess of bilaterally nonfunctioning posterior communicating arteries was observed both in the children with the intrauterine growth restriction-variant phenotype and their mothers as compared with the control groups. Significantly increased proportions of joint hypermobility and skin softness were observed in the intrauterine growth restriction-variant children as compared with controls subjects. Children with the intrauterine growth restriction-variant phenotype and their mothers showed bilateral distortion product-evoked otoacoustic emissions notches versus none in the control subjects, with an associated reduction of the area under the curve in both the intrauterine growth restriction-variant children and their mothers. No significant differences between the variant and control groups regarding the fathers were observed.

CONCLUSIONS

We propose that the observed phenotypical constellation may represent an unrecognized variant of intrauterine growth restriction.