Developmental facial paralysis: a review

The Monocle Sign on 18F-FDG PET Indicates Contralateral Peripheral Facial Nerve Palsy

BACKGROUND

The aim of our study was to retrospectively analyze FDG PET/CT data in patients with facial nerve palsy (FNP) for the presence of the monocle sign.

PATIENTS AND METHODS

A total of 85 patients with unilateral FNP were included into our study, thereof 73 with peripheral FNP and 12 with central FNP. FDG uptake (SUVmax, SUVmean, total lesion glycolysis) was measured in both orbicularis oculi muscles (OOMs). FDG uptake of paretic and nonparetic muscles was compared in patients with FNP (Wilcoxon test and Mann-Whitney U test) and was also compared with FDG uptake in 33 patients without FNP (Mann-Whitney U test). SUVmax ratios of OOM were compared. A receiver operating characteristic curve and Youden Index were used to determine the optimal cutoff SUVmax ratio for the prevalence of contralateral peripheral FNP.

RESULTS

The SUVmax ratio of OOM was significantly higher in patients with peripheral FNP compared with patients with central FNP and those without FNP (1.70 ± 0.94 vs 1.16 ± 0.09 vs 1.18 ± 0.21, respectively; P < 0.001). The SUVmax ratio of OOM yielded an area under the curve (AUC) of 0.719 (95% confidence interval, 0.630-0.809), with an optimal cutoff of 1.41, yielding a specificity of 94.4% and a sensitivity of 44.1% for identifying contralateral peripheral FNP. One hundred percent specificity is achieved using a cutoff of 1.91 (sensitivity, 29.4%).

CONCLUSIONS

Asymmetrically increased FDG uptake of the OOM (the "monocle sign") indicates contralateral peripheral FNP. A nearly 2-fold higher SUVmax represents a practically useful cutoff.

Congenital facial nerve palsy: Single center study

Objectives

This study will list the most common comorbidities of congenital facial nerve palsy and how to detect and treat them, with special attention for ENT-problems such as hearing loss. Congenital facial nerve palsy is a very rare entity but in UZ Brussels hospital there was a follow-up of 16 children in the last 30 years.

Methods

Literature review has been done, combined with thorough research of our own series of 16 children with congenital facial nerve palsy.

Results

Congenital facial nerve palsy can be part of a known syndrome, most commonly Moebius syndrome, but can also appear solely. It appears often bilateral and with a severe gradation. In our series, hearing loss is frequently seen in association with congenital facial nerve palsy. Other abnormalities are dysfunction of the abducens nerve, ophthalmological problems, retro- or micrognathism and abnormalities of limbs or heart. The majority of the children in our series underwent radiological imaging (CT and/or MRI): the facial nerve but also the vestibulocochlear nerve and middle and inner ear can be evaluated.

Conclusion

A multidisciplinary approach of congenital facial nerve palsy is recommended as it can affect various bodily functions. Radiological imaging needs to be done to acquire additional information that can be useful for diagnostic and therapeutic purposes. Although congenital facial nerve palsy may not be treatable itself, its comorbidities can be treated and improve the quality of life of the affected child.

Acute Peripheral Facial Nerve Palsy in Children and Adolescents: Clinical Aspects and Treatment Modalities

BACKGROUND

Peripheral facial nerve palsy is a relatively frequent, rather idiopathic, and isolated nonprogressive disorder with a tendency toward spontaneous recovery in children. It is primarily characterized by unilateral paresis or paralysis of the mimic musculature affecting verbal communication, social interactions, and quality of life.

OBJECTIVE

This study aimed to evaluate the clinical aspects and efficacy of different therapeutic modalities in the population of children and adolescents with acute peripheral facial nerve palsy, the quality and recovery rate in comparison to different therapy modalities and etiological factors as well as to determine parameters of recovery according to the age of patients.

METHODS

The retrospective study included children and adolescents (n=129) with an acute onset of peripheral facial nerve palsy, diagnosed and treated in the Clinic of Neurology and Psychiatry for Children and Youth in Belgrade (2000-2018). The mean age of the patients was 11.53 years (SD±4.41). Gender distribution: 56.6% female and 43.4% male patients.

RESULTS

There were 118 (91.5%) patients with partial and 11 (8.5%) patients with complete paralysis. Left-sided palsy occurred in 67 (51.9%) patients, right-sided in 58 (45.0%), while there were 4 (3.1%) bilateral paralyses. The most common etiological factor was idiopathic (Bell's palsy) - 74 (57.4%) patients followed by middle ear infections - 16 (12.4%). Regardless of etiology, age, and therapy protocols, there was a significant recovery in most of the patients (p<0.001), without significant differences in recovery rate. Comparison of inpatient and outpatient populations showed significant differences regarding the number of relapses, severity of clinical presentation, and recovery rate in relation to etiology.

CONCLUSION

Bell's palsy is shown to be the most common cause of peripheral facial nerve palsy in children and adolescents, regardless of gender. It is followed by mid-ear infections, respiratory infections, and exposure to cold. Most children and adolescents recovered in three weeks after initial presentation, regardless of etiology, age, and therapy.

Congenital Facial Paralysis Revealing an Aplasic Facial Nerve: A Report of Two Cases

ABSTRACT

Congenital facial palsy is a rare condition, usually related to a traumatic event during birth or as a feature of a syndrome. In this report, two cases of infants with peripheral facial palsy since birth are described, in which magnetic resonance imaging demonstrated unilateral aplasia of the facial nerve. There are only a few cases with similar findings described in the literature. A multidisciplinary approach is recommended to provide the best care. Although no reinnervation of the facial muscles is likely to occur, rehabilitative therapies may be valuable as complementary treatments.

Facial Asymmetry: A Narrative Review of the Most Common Neurological Causes

Symmetry of the face is one of the most important features for the perception of attractiveness. Asymmetry of the face means that the right and left sides of the face are not identical. Subclinical facial asymmetry is very common in the general population. Most people have some slight facial asymmetry, and this is the normal biological situation in humans. Abnormalities from soft tissue, dental, and skeletal elements lead to facial asymmetry. Asymmetry has many causal factors, and its aetiology includes both congenital and acquired conditions. Neurological facial asymmetry is scarcely addressed in the dental literature. In this narrative review, we focus on the most common neurological causes of facial asymmetry. From a neurological point of view, facial asymmetry can result from disturbances of the cranial nerves, developmental disorders, or myopathies. In the broad range of differential diagnostics of facial asymmetry, neurological abnormalities should be taken into consideration. The treatment must be related to the underlying cause. Complete knowledge of the aetiological factors and the character of the asymmetry plays a crucial role in formulating a treatment plan.

Facial Asymmetry in a Newly Born Baby: Diagnostic Challenge!

Introduction:

Facial asymmetry during crying in neonates is an important entity which might be due to an underlying true paralysis of the facial nerve or due to the benign overlooked diagnosis of congenital absence of the depressor angularis oris muscle (DAOM).

Case Report:

We report a full-term newborn delivered by normal spontaneous vertex delivery with uneventful pregnancy and Apgar score of 9 and 10 at 1 and 5 minutes respectively. His parents are first-degree cousins with 4 living normal siblings. His birth weight was appropriate for his gestational age. His initial neonatal assessment was normal apart from facial asymmetry during crying in the form of deviation of the angle of the mouth to the left with an otherwise normal facial appearance. The facial asymmetry disappears at rest (without crying). This condition usually poses a diagnostic dilemma. Developmental and traumatic facial paralysis and being part of some syndromes like Mobius and CHARGE syndromes are among the most important differential diagnosis but the disappearance of the facial asymmetry at rest is diagnostic of absent DAOM which is a relatively common but missed diagnosis.

Conclusions:

Pediatricians should be aware about the diagnosis of DAOM in neonates with asymmetric crying face if the face was completely normal at rest with deviation of the angle of the mouth on crying which disappears on rest.

Etv1 Controls the Establishment of Non-overlapping Motor Innervation of Neighboring Facial Muscles during Development

The somatotopic motor-neuron projections onto their cognate target muscles are essential for coordinated movement, but how that occurs for facial motor circuits, which have critical roles in respiratory and interactive behaviors, is poorly understood. We report extensive molecular heterogeneity in developing facial motor neurons in the mouse and identify markers of subnuclei and the motor pools innervating specific facial muscles. Facial subnuclei differentiate during migration to the ventral hindbrain, where neurons with progressively later birth dates—and evolutionarily more recent functions—settle in more-lateral positions. One subpopulation marker, ETV1, determines both positional and target muscle identity for neurons of the dorsolateral (DL) subnucleus. In Etv1 mutants, many markers of DL differentiation are lost, and individual motor pools project indifferently to their own and neighboring muscle targets. The resulting aberrant activation patterns are reminiscent of the facial synkinesis observed in humans after facial nerve injury.

Tenney et al. demonstrate that embryonic facial motor neurons are transcriptionally diverse as they establish somatotopic innervation of the facial muscles, a process that requires the transcription factor ETV1. Facial-motor axon-targeting errors in Etv1 mutants cause coordination of whisking and eyeblink evocative of human blepharospasm.

Developmental unilateral facial palsy in a newborn: six cases and literature review

Unilateral facial palsy in a newborn is rarely caused by a developmental defect. It occurs either isolated or in the context of a syndrome. This article describes a multidisciplinary approach towards unilateral, isolated congenital facial palsy along with a literature review. We report six patients, three boys and three girls, who presented with a unilateral facial palsy at birth. Clinical assessment was performed by an ear-nose-throat (ENT) surgeon, a pediatric neurologist, and an ophthalmologist. Magnetic resonance imaging (MRI) of the posterior fossa and computerized tomography (CT) of the temporal bone were requested to exclude structural anomalies of the facial nerve. Imaging revealed the underlying cause in five patients out of six (80%), showing an ipsilateral facial nerve aplasia or hypoplasia. These findings point towards an underlying developmental defect and underscore the importance of MRI in the diagnostic work-up. Surgical and non-surgical therapies were discussed with the parents.Conclusion: Congenital unilateral facial palsy caused by a developmental defect outside the context of a syndrome is rare. A multidisciplinary approach is recommended to differentiate between various causes and to initiate timely treatment.What is Known:• Congenital facial palsy is mostly caused by environmental/external fcators.• However in rare cases it can be developmental defect.What is New:• This paper describes 6 cases of isolated congenital facial palsy related to a developmental defect and presents the largest case series in the literature caused by aplasia/hypoplasia of the facial nerve.• MRI and CT-imaging allow for an assessment of the facial nerve at the root entry zone of the brainstem and along its course through the middle ear or the face. Moreover, they proved to be helpful in differentiating between several causes of congenital facial palsy.

Autonomic Responses to Emotional Stimuli in Children Affected by Facial Palsy: The Case of Moebius Syndrome

According to embodied simulation theories, others' emotions are recognized by the unconscious mimicking of observed facial expressions, which requires the implicit activation of the motor programs that produce a specific expression. Motor responses performed during the expression of a given emotion are hypothesized to be directly linked to autonomic responses associated with that emotional behavior. We tested this hypothesis in 9 children (M_age = 5.66) affected by Moebius syndrome (MBS) and 15 control children (M_age = 6.6). MBS is a neurological congenital disorder characterized by underdevelopment of the VI and VII cranial nerves, which results in paralysis of the face. Moebius patients' inability to produce facial expressions impairs their capacity to communicate emotions through the face. We therefore assessed Moebius children's autonomic response to emotional stimuli (video cartoons) by means of functional infrared thermal (fIRT) imaging. Patients showed weaker temperature changes compared to controls, suggesting impaired autonomic activity. They also showed difficulties in recognizing facial emotions from static illustrations. These findings reveal that the impairment of facial movement attenuates the intensity of emotional experience, probably through the diminished activation of autonomic responses associated with emotional stimuli. The current study is the first to investigate emotional responses in MBS children, providing important insights into the role of facial expressions in emotional processing during early development.

Congenital facial palsy and emotion processing: The case of Moebius syndrome

According to the Darwinian perspective, facial expressions of emotions evolved to quickly communicate emotional states and would serve adaptive functions that promote social interactions. Embodied cognition theories suggest that we understand others' emotions by reproducing the perceived expression in our own facial musculature (facial mimicry) and the mere observation of a facial expression can evoke the corresponding emotion in the perceivers. Consequently, the inability to form facial expressions would affect the experience of emotional understanding. In this review, we aimed at providing account on the link between the lack of emotion production and the mechanisms of emotion processing. We address this issue by taking into account Moebius syndrome, a rare neurological disorder that primarily affects the muscles controlling facial expressions. Individuals with Moebius syndrome are born with facial paralysis and inability to form facial expressions. This makes them the ideal population to study whether facial mimicry is necessary for emotion understanding. Here, we discuss behavioral ambiguous/mixed results on emotion recognition deficits in Moebius syndrome suggesting the need to investigate further aspects of emotional processing such as the physiological responses associated with the emotional experience during developmental age.

Blink Restoration in Long-standing Facial Paralysis: Use of Free Neurovascular Platysma Transfer

Supplemental Digital Content is available in the text.

Background:

Since 2004, microneurovascular platysma transfer has been used for dynamic eye closure in long-standing facial palsy. The idea was initially presented by Lee and Terzis in 1984 but abandoned owing to its transfer difficulty. This muscle transfer allows forceful closure and blink restoration.

Methods:

This study included 24 patients operated between 2004 and 2014 for long-standing facial palsy. In the first step of the procedure, a cross-facial nerve graft was employed to transfer the motor nerve fibers from the normal side to the paralyzed side responsible for eye closure. Simultaneously, a dynamic reanimation of the mouth was conducted. After 9 months, a 4 × 9-cm platysma was transferred on its neurovascular pedicle. Revascularization was performed on the temporal vessels. Nerve coaptation between the cross-facial nerve graft and motor nerve of the platysma was also performed.

Results:

Twenty-one (88%) newly reconstructed orbicularis oculis displayed a good to excellent function. In 62% of the patients, a natural appearance and closure of the previously paralyzed eye and a return of spontaneous blinking were observed.

Conclusions:

Compared with classical techniques (eg, gold weight implantation and temporalis transfer), platysma transfer is the only feasible method of restoring eye closure because of its special architecture and fiber-type distribution.

Magnetic resonance imaging of developmental facial paresis: a spectrum of complex anomalies

PURPOSE

Despite its clinical implications, the MRI features of developmental facial paresis (DFP) were described in a few case reports. This study aims to describe MRI features of DFP in relation to the embryological development with a proposed radiological new grading system.

METHODS

The clinical records and MRI of the brain and internal auditory canal of 11 children with DFP were retrospectively reviewed. The following sequences were analyzed: axial, oblique sagittal SPACE of the internal auditory canal and brainstem; axial T2, T1WI and coronal T2WI of the brain. The severity of the maldevelopment of the seventh nerve was graded from 0 to 4: 0 = no abnormalities, 1 = unilateral facial nerve hypoplasia, 2 = unilateral facial nerve aplasia, 3 = aplasia or hypoplasia involving facial nerves on both sides, and 4 = facial nerve aplasia or hypoplasia associated with other cranial nerve palsy.

RESULTS

Isolated facial nerve palsy was diagnosed in seven patients. It was of grade 1 in five and grade 3 in two. Hypoplasia of the nerve with interrupted course was encountered in two cases. Other associated cranial nerve abnormalities (grade 4) were seen in four patients; two of them were diagnosed previously as Moebius syndrome. In addition to inner ear anomalies, middle and external ear and parotid gland anomalies were described.

CONCLUSION

To our knowledge, this is the largest series of patients with DFP that represents a continuum of isolated and combined malformations. Understanding of embryological basis can give insights into the anomalous development of the facial nerve.

Facial Paralysis in Patients With Hemifacial Microsomia: Frequency, Distribution, and Association With Other OMENS Abnormalities

Although facial paralysis is a fundamental feature of hemifacial microsomia, the frequency and distribution of nerve abnormalities in patients with hemifacial microsomia remain unclear. In this study, the authors classified 1125 cases with microtia (including 339 patients with hemifacial microsomia and 786 with isolated microtia) according to Orbital Distortion Mandibular Hypoplasia Ear Anomaly Nerve Involvement Soft Tissue Dependency (OMENS) scheme. Then, the authors performed an independent analysis to describe the distribution feature of nerve abnormalities and reveal the possible relationships between facial paralysis and the other 4 fundamental features in the OMENS system. Results revealed that facial paralysis is present 23.9% of patients with hemifacial microsomia. The frontal-temporal branch is the most vulnerable branch in the total 1125 cases with microtia. The occurrence of facial paralysis is positively correlated with mandibular hypoplasia and soft tissue deficiency both in the total 1125 cases and the hemifacial microsomia patients. Orbital asymmetry is related to facial paralysis only in the total microtia cases, and ear deformity is related to facial paralysis only in hemifacial microsomia patients. No significant association was found between the severity of facial paralysis and any of the other 4 OMENS anomalies. These data suggest that the occurrence of facial paralysis may be associated with other OMENS abnormalities. The presence of serious mandibular hypoplasia or soft tissue deficiency should alert the clinician to a high possibility but not a high severity of facial paralysis.

The masseteric nerve: An anatomical study in Thai population with an emphasis on its use in facial reanimation

BACKGROUND

The use of the masseteric nerve has been escalated as a donor nerve for facial reanimation in facial palsy patient (Wang et al., 2014; Manktelow et al., 2006; Klebuc, 2011; Bianchi et al., 2012; Zuker et al., 2000; Bae et al., 2006; Terzis, Konofaos, 2013; Terzis, Olivares, 2009; Bianchi et al., 2014). Previous studies had been done in Euro-Caucasian cadavers (Kaya et al., 2014). However, difference in anatomical details does exist between Asian and Euro-Caucasian population (Tzou et al., 2005; Farkas et al., 2005). In this study, we have conducted a detailed anatomical study of masseteric nerve in adult Thai cadavers which might elaborate better details of masseteric nerve anatomy in Asian population.

METHODS

Twenty eight hemifaces from 14 adult Thai non-formaldehyde preserved soft cadavers were used in this study. The anatomical pathway of the masseteric nerve was defined relating to four surgical landmarks which are auricular tragus, zygomatic arch, posterior border of the temporomandibular joint, and alar base.

RESULTS

The suitable starting area for the masseteric nerve dissection is 3.7 ± 0.4 cm anterior to the auricular tragus at the level of 0.8 ± 0.2 cm inferior to the zygomatic arch. The nerve was found 1.1 ± 0.2 cm deep to the superficial surface of the masseteric fascia and 1.7 ± 0.2 cm anterior to the posterior border of the temporomandibular joint. The point where the nerve giving off its first branch as it courses distally is 7.3 ± 0.7 cm from the ipsilateral alar base. The mean diameter of this nerve is 1.59 ± 0.42 mm.

CONCLUSION

The anatomy of the masseteric nerve during its course in the muscle is consistent. In our study, the details of its anatomy is slightly different from the previous works which were performed in the Euro-Caucasian cadavers.

A Novel Loss-of-Function Mutation in HOXB1 Associated with Autosomal Recessive Hereditary Congenital Facial Palsy in a Large Iranian Family

Hereditary congenital facial palsy (HCFP) is a rare congenital cranial dysinnervation disorder, recognisable by non-progressive isolated facial nerve palsy (cranial nerve VII). It is caused by developmental abnormalities of the facial nerve nucleus and its nerve. So far, 4 homozygous mutations have been identified in 5 unrelated families (12 patients) with HCFP worldwide. In this study, a large Iranian consanguineous kindred with 5 members affected by HCFP underwent thorough clinical and genetic evaluation. The candidate gene HOXB1 was screened and analysed by Sanger sequencing. As in previous cases, the most remarkable findings in the affected members of the family were mask-like faces, bilateral facial palsy with variable sensorineural hearing loss, and some dysmorphic features. Direct sequencing of the candidate gene HOXB1 identified a novel homozygous frameshift mutation (c.296_302del; p.Y99Wfs*20) which co-segregated with the disease phenotype within the extended family. Our findings expand the mutational spectrum of HOXB1 involved in HCFP and consolidate the role of the gene in the development of autosomal recessive HCFP. Moreover, the truncating mutation identified in this family leads to a broadly similar presentation and severity observed in previous patients with nonsense and missense mutations. This study characterises and defines the phenotypic features of this rare syndrome in a larger family than has previously been reported.

Hemifacial Microsomia : Clinicoradiological Insight and Report of a Case

Background

Hemifacial microsomia is a congenital malformation characterized by deficiency in the amount of hard and soft tissue on one side of the face. It is primarily a syndrome of the first branchial arch, involving underdevelopment of the temporomandibular joint, masticatory muscles, mandibular ramus, ear and, occasionally, defects in facial nerve and muscles.

Case Details

The clinical and radiological manifestations of a 14-year-old male patient having hemifacial microsomia is highlighted in this article to enhance our knowledge and diagnostic skill of this rare entity.

Conclusion

This case illustrates that early diagnosis and intervention in a patient with hemifacial microsomia is quintessential for proper functioning and esthetics of the orofacial structures, which will lead to a better prognosis.

Facial Asymmetry in a Crying Newborn: A Comparison of Two Cases and Review of Literature

Facial asymmetry in a crying newborn can be due to a variety of different causes. Neonatal asymmetric crying facies (NACF) is a specific phenotype, which is often underrecognized. It is defined as asymmetry of the mouth and lips with grimacing or smiling, but a symmetric appearance at rest. NACF needs to be differentiated from complete facial palsy in a newborn, which can occur due to traumatic or developmental etiologies. Developmental causes can be present in isolation or may be a part of a recognized syndrome. While asymmetric lower lip depression may be seen in both conditions, complete facial palsy is also associated with upper and mid face deformities. We present a case of NACF and compare it to a case of facial palsy due to perinatal trauma. The purpose of this case series is to clarify some of the confusing nomenclatures and highlight the differences in the physical exam findings, diagnosis, and eventual prognosis of these cases.

Homozygous HOXB1 loss-of-function mutation in a large family with hereditary congenital facial paresis

Hereditary congenital facial paresis (HCFP) belongs to the congenital cranial dysinnervation disorders. HCFP is characterized by the isolated dysfunction of the seventh cranial nerve and can be associated with hearing loss, strabismus, and orofacial anomalies. Möbius syndrome shares facial palsy with HCFP, but is additionally characterized by limited abduction of the eye(s). Genetic heterogeneity has been documented for HCFP as one locus mapped to chromosome 3q21-q22 (HCFP1) and a second to 10q21.3-q22.1 (HCFP2). The only known causative gene for HCFP is HOXB1 (17q21; HCFP3), encoding a homeodomain-containing transcription factor of the HOX gene family, which are master regulators of early developmental processes. The previously reported HOXB1 mutations change arginine 207 to another residue in the homeodomain and alter binding capacity of HOXB1 for transcriptional co-regulators and DNA. We performed whole exome sequencing in HCFP-affected individuals of a large consanguineous Moroccan family. The homozygous nonsense variant c.66C>G/p.(Tyr22*) in HOXB1 was identified in the four patients with HCFP and ear malformations, while healthy family members carried the mutation in the heterozygous state. This is the first disease-associated HOXB1 mutation with a likely loss-of-function effect suggesting that all HOXB1 variants reported so far also have severe impact on activity of this transcriptional regulator. © 2016 Wiley Periodicals, Inc.

Single-stage dynamic reanimation of the smile in irreversible facial paralysis by free functional muscle transfer

Unilateral facial paralysis is a common disease that is associated with significant functional, aesthetic and psychological issues. Though idiopathic facial paralysis (Bell's palsy) is the most common diagnosis, patients can also present with a history of physical trauma, infectious disease, tumor, or iatrogenic facial paralysis. Early repair within one year of injury can be achieved by direct nerve repair, cross-face nerve grafting or regional nerve transfer. It is due to muscle atrophy that in long lasting facial paralysis complex reconstructive methods have to be applied. Instead of one single procedure, different surgical approaches have to be considered to alleviate the various components of the paralysis. The reconstruction of a spontaneous dynamic smile with a symmetric resting tone is a crucial factor to overcome the functional deficits and the social handicap that are associated with facial paralysis. Although numerous surgical techniques have been described, a two-stage approach with an initial cross-facial nerve grafting followed by a free functional muscle transfer is most frequently applied. In selected patients however, a single-stage reconstruction using the motor nerve to the masseter as donor nerve is superior to a two-stage repair. The gracilis muscle is most commonly used for reconstruction, as it presents with a constant anatomy, a simple dissection and minimal donor site morbidity. Here we demonstrate the pre-operative work-up, the post-operative management, and precisely describe the surgical procedure of single-stage microsurgical reconstruction of the smile by free functional gracilis muscle transfer in a step by step protocol. We further illustrate common pitfalls and provide useful tips which should enable the reader to truly comprehend the procedure. We further discuss indications and limitations of the technique and demonstrate representative results.

Advances in diagnosis and non-surgical treatment of Bell's palsy

Bell's palsy is a commonly seen cranial nerve disease and can result in compromised facial appearance and functions. Its etiology, prognosis and treatment are still being debated. This paper is a review of recent development in the understanding of etiology, diagnosis and non-surgical treatment of Bell's palsy.

Examining the genetics of congenital facial paralysis--a closer look at Moebius syndrome

OBJECTIVES

The molecular underpinnings of Moebius syndrome (MBS) are diverse. This article provides a comprehensive summation of the genetic and etiologic literature underlying this disorder. Elucidating the genetic causes of the disorder can aid in earlier detection and treatment planning.

DESIGN

Articles from 1880-2013 were selected and reviewed by six researchers to understand all of the molecular theories and chronicity of advancements in the literature.

RESULTS

Mutations in the MBS1, MBS2, and MBS3 gene loci all have contributed to the development of MBS through various pathways. HOX family genes coding for homeobox domains, also, have been implicated in the abnormal development of the human brain. These are among the numerous genes that have been linked to the development of MBS.

CONCLUSION

Our study codified nascent findings of the molecular determinants of MBS. These findings add to a growing database of MBS-associated mutations and can be used to diagnose MBS and clarify pathogenesis.

Hemifacial microsomia: a series of three case reports

Hemifacial Microsomia (HFM) is an asymmetric craniofacial malformation which results in hypoplasia of the components of the first and second branchial arches. There can be various anomalies, which include conductive hearing loss which is caused by external and middle ear deformities. HFM is the second most common congenital facial anomaly which is seen after cleft lip/palate. For the pre-surgical evaluation of this anomaly, diagnostic imaging and classification of the facial structures, based on OMENS classification, is of prime importance. The management of this developmental malformation is multidisciplinary. We are presenting a series of three cases with diverse clinical and radiographic features which ranged from mild facial asymmetry and ear malformation to facial paralysis.

Facial motor neuron migration advances

During development, the migration of specific neuronal subtypes is required for the correct establishment of neural circuits. In mice and zebrafish, facial branchiomotor (FBM) neurons undergo a tangential migration from rhombomere 4 caudally through the hindbrain. Recent advances in the field have capitalized on genetic studies in zebrafish and mouse, and high-resolution time-lapse imaging in zebrafish. Planar cell polarity signaling has emerged as a critical conserved factor in FBM neuron migration, functioning both within the neurons and their environment. In zebrafish, migration depends on specialized 'pioneer' neurons to lead follower FBM neurons through the hindbrain, and on interactions with structural components including pre-laid axon tracts and the basement membrane. Despite fundamental conservation, species-specific differences in migration mechanisms are being uncovered.

First branchial cleft fistula presenting with internal opening on the Eustachian tube: Illustrated cases and literature review

OBJECTIVE

Two cases of first branchial cleft fistula with internal opening on the Eustachian tube are reported and the diagnosis, management and embryological hypothesis are discussed.

DESIGN

Retrospective study and review of the literature.

RESULTS

Both patients were young boys with first branchial cleft anomaly clearly identified by computed tomography fistulography scan and direct Methylene Blue dye injection. In both cases, surgical removal revealed a fistula with internal opening located on the Eustachian tube near the nasopharynx.

DISCUSSION

The main embryological theories and classification are reviewed. A connection between the theories of first branchial apparatus development and the classification by Work might explain the reported clinical association.