Congenital Facial Paralysis 

Updated: Jan 07, 2019
Author: Alan D Bruns, MD, FACS; Chief Editor: Arlen D Meyers, MD, MBA 

Overview

Background

Congenital (present at birth) facial paralysis is uncommon and, when present, may cause multiple problems for the newborn, such as difficulty with nursing and incomplete eye closure. If the paralysis does not resolve, it may affect the child’s future speech, expressions of emotion, and mastication. This article discusses the etiologies, evaluation, diagnostic testing, and treatment options for this disorder.[1]

Congenital facial paralysis is classified as traumatic or developmental, unilateral or bilateral, and complete or incomplete (paresis). Determining the etiology is important because the prognosis and treatment differ, depending on the underlying pathophysiology. An appropriate history and physical examination usually resolve the origin, but radiographic imaging and neuromuscular testing may be necessary for treatment planning.

An extended physical examination is needed to exclude other congenital malformations. Associated anomalies may include microtia, inner ear abnormalities, extraocular muscle paralysis, facial hypoplasia, other cranial nerve deficiencies, cleft palate, internal organ disorders, and extremity deformities.

A child with Möbius syndrome is depicted below.

Child with Möbius syndrome, eyes open. Image court Child with Möbius syndrome, eyes open. Image courtesy of M.J. Biavati.

Epidemiology

Frequency

Congenital facial paralysis accounts for 8-14% of all pediatric cases of facial paralysis.[2] The incidence of facial paralysis in live births is 0.8-2.1 per 1000 births, and, of these, 88% are associated with a difficult labor. Of patients with birth trauma, 67-91% are associated with forceps delivery.[3, 4, 5] Developmental causes include those associated with syndromes and teratogens. An example of a development cause is Möbius syndrome, which has an incidence of 1 per 50,000 births.[6] A common disorder that resembles a unilateral partial nerve paralysis is congenital unilateral lower lip palsy (CULLP), also known as neonatal asymmetric crying facies, that occurs in 1 out of 160 live births.[7]  The estimated prevalence of facioscapulohumeral muscular dystrophy (FSH MD) is between 1/20,000 and 1/8000, making it the world’s third-most-common inherited myopathy.[8]

Etiology

The cause of congenital facial paralysis is associated with either a traumatic injury or developmental deformities of the brain or facial nerve (cranial nerve VII).[9]

Trauma

The most frequent cause of unilateral congenital facial palsy is birth trauma related to a difficult delivery. Risk factors include forceps delivery, birth weight of more than 3500 g, and primiparity.[3] The injury from forceps is induced by the pressure of the posterior blade that compresses the bone overlying the vertical segment of the facial canal.[6] The facial nerve is also susceptible to trauma as it exits the stylomastoid foramen, where soft tissue compression can lead to a transient facial neurapraxia. Complete transection of the facial nerve caused by birth trauma is rare. Intrauterine trauma can also occur from pressure on the infant's face by the sacral prominence during labor.[10]

Developmental causes

The causes of developmental facial paralysis are numerous and may be associated with syndromes and teratogens.

Möbius syndrome

A broad spectrum of clinical and pathological findings characterize this syndrome. The patient usually presents with bilateral paralysis of the facial nerve with unilateral or bilateral palsy of the abducens nerve (cranial nerve VI). This syndrome may also affect other cranial nerves, with XII being the next most common. It often involves abnormalities of the extremities, including absence of the pectoralis major muscle in Poland syndrome.[11, 12, 13]

A few families with Möbius syndrome have been described, but most cases are sporadic. Associations have also been made with fetal exposure to misoprostol, cocaine, ergotamine.[14, 15, 16] Malformations of the limbs and other cranial nerves are often identified with this syndrome. Several theories regarding the pathogenesis of Möbius syndrome are as follows:

  • Aplasia or hypoplasia of cranial nerve nuclei

  • Nuclear destruction

  • Peripheral nerve abnormality

  • Primary myopathy

  • Disruption sequence in vascular territory of subclavian artery

Autopsy studies have supported all of the causes listed above. A neurophysiologic study of patients with sporadic Mobius syndrome demonstrated 2 distinct groups characterized by 1) increased facial distal motor latencies (DML) and poor recruitment of small neuropathic motor unit action potentials (MAUP) and 2) normal facial DMLs and neuropathic MAUPs. The functional impairment of facial movements appears to be caused by a nuclear or peripheral site of lesion without brainstem interneuronal involvement.[17]

Hemifacial microsomia

Several subcategories exist that fall under the spectrum of oculo-auriculo-vertebral disorders that consists of anomalies of the first and second branchial arches. This is a common craniofacial disorder characterized by a wide spectrum of anomalies, including a conductive hearing loss due to external and middle ear deformities.

The prevalence of sensorineural hearing loss (SNHL), as well as facial nerve dysfunction, is underappreciated. A retrospective study by Carvalho et al found that in a cohort of pediatric patients, hearing loss was present in 74 of 99 children (75%), with a conductive component in 73 patients. Sensorineural hearing loss was present in 11 patients (11%), with mixed hearing loss in most patients. Nearly a quarter of the patients (22 of 99 [22%]) had facial nerve dysfunction, but only 1 patient had facial palsy on the same side as the SNHL.[18] Lower facial weakness occurs in 10-20% of cases and is likely related to bony involvement in the region of the facial canal. A nonhereditary variant of hemifacial microsomia is Goldenhar syndrome, which has vertebral anomalies and epibulbar dermoids.

A literature review by Cline et al indicated that 10-45% of patients with hemifacial microsomia/oculu-auriculo-vertebral spectrum have facial weakness and that in most of these cases, all facial nerve branches or just the lower branches are involved. The investigators suggested that facial weakness in hemifacial microsomia results from the effect of temporal bone dysmorphogenesis on the facial nerve.[19]

A study by Li et al found that that out of 339 patients with hemifacial microsomia, 23.9% had facial paralysis, with paralysis reported to be more likely to occur in the presence of mandibular hypoplasia and soft tissue deficiency.[20]

22q11.2 deletion syndrome (22qDS)

This syndrome may include patients with velocardiofacial syndrome or DiGeorge syndrome. Association of facial nerve palsy and congenital heart disease versus cardiofacial syndrome are different only on clinical grounds, so both conditions can be genetically identical and form part of the spectrum of defects associated with chromosome 22q11 deletions.[21, 22]

Albers-Schönberg disease

Osteopetrosis, a rare cause of paralysis at birth, may also manifest later in childhood.

CHARGE syndrome

This acronym stands for colobomata, heart disease, atresia of choanae, retarded growth, genital hypoplasia, and ear anomalies. Multiple cranial nerves may be involved in this condition. At least 1 cranial nerve is involved in 75% of cases, and 2 or more cranial nerves are involved in 58% of cases. Of patients who have cranial nerve involvement, 60% involve cranial nerve VIII, 43% involve cranial nerve VII, and 30% involve cranial nerves IX and X.[23, 24]

Facioscapulohumeral muscular dystrophy

FSH MD is an autosomal dominant condition marked by a steadily progressive familial distal myopathy associated with weakness of the face, jaw, neck, and levators of the eyelid.[25] At birth, infants present with facial diplegia; however, lateral gaze is intact (in contrast to Möbius syndrome). Later in childhood, distal progressive myopathy develops. Intelligence and life span are normal and the spectrum of disability is broad. Flaccid dysarthria results from the facial muscle paralysis. A pair of siblings had FSH MD that was accompanied by the unusual finding of sensorineural hearing loss.[26]

A prospective, cross-sectional study by Goselink et al indicated that muscle weakness and systemic features (particularly hearing loss, reduced respiratory function, and spinal deformities) tend to be more severe in patients with early onset facioscapulohumeral muscular dystrophy (FSH MD) than in those with the classic-onset form of the disorder. The study also found that 46% of patients with early onset FSH MD had de novo mutations, compared with 4% of individuals with the classic-onset condition.[27]

Congenital unilateral lower lip paralysis/asymmetric crying facies

This is not usually considered a true congenital facial paralysis, but these patients present with drooping of the lower lip toward the unaffected side when laughing or crying and normal appearance of the face at rest. Congenital unilateral lower lip paralysis (CULLP) can appear in clusters with cardiac anomalies, which should provoke an evaluation for VCFS. The etiology of CULLP is most often attributed to hypoplasia or congenital absence of the depressor anguli oris or the depressor labii inferioris muscle. A second theory proposes that a primary brainstem infarction occurs and causes secondary hypoplasia of the musculature.[7, 28, 29] Almost 10% (9.4%) of cases are associated with major malformations, most commonly heart defects. Many of those patients with the cardio facial syndrome have the 22q11.2 deletion. Chromosomal analysis for these patients is recommended.[26]

Teratogens associated with facial nerve paralysis

See the list below:

  • Thalidomide: This sedative and antiemetic is associated with phocomelia, arrested development of the ear, and paralysis of the facial and abducens nerves. This medication is currently used in patients with leprosy, multiple myeloma, other cancer treatments.[14]

  • Misoprostol: This synthetic prostaglandin is used to prevent and treat gastrointestinal lesions induced by nonsteroidal anti-inflammatory drugs. It may stimulate uterine contractions and has been used with mifepristone or methotrexate to induce an abortion. When used alone, up to 80% of pregnancies continue to term. In a study of 96 infants with Möbius syndrome and 96 infants with neural tube defects, 49% of infants with Möbius syndrome were exposed to misoprostol in utero, compared with 3% of infants with neural tube defects. The cause of Möbius syndrome associated with misoprostol may be vascular disruption of the subclavian artery in week 4-6, causing an ischemic brain event.[30]

Presentation

Newborn children with facial paralysis may present with noted asymmetric facial movement, incomplete eye closing, and difficulties feeding. They may have other more significant symptoms from other congenital defects.

Determine the etiology of congenital facial nerve paralysis based on birth history, family history, physical examination, radiologic studies, and neurophysiologic tests.

Obtaining a thorough birth history in congenital facial paralysis is important. When the etiology is traumatic, the evidence often supports difficult labor caused by cephalopelvic disproportion. Risks for difficult labor include primiparity and birth weight more than 3500 g. The use of middle forceps delivery (as opposed to low forceps) also increases the risk of injury to the facial nerve, as does prolonged second-stage labor.[3]

A family history positive for facial paralysis or other congenital anomalies increases the suspicion for a developmental cause of the facial paralysis.

Examine the infant bilaterally and evaluate both the upper and lower portions of the face. Looking at forehead wrinkling, eye closure, and lip movement. A bilateral facial palsy is frequently incomplete, affecting either the lower or upper portion of the face. This helps to distinguish developmental causes of congenital facial paralysis from traumatic causes that often involves the upper and lower face equally and are often unilateral.

A traumatic etiology often reveals a unilateral facial paralysis with ecchymosis, hemotympanum, facial swelling, and severe head molding. Documenting these findings during the immediate neonatal period assists in establishing an etiology.[31]

The examination needs to evaluate the other cranial nerves and rule out other congenital anomalies.

Often, a mild paresis of the facial nerve is not noticed at birth, especially if the injury is bilateral. When facial nerve paralysis is associated with hemifacial microsomia or other craniofacial abnormalities, the facial nerve is often not noted to be weak until the child grows and a more pronounced asymmetry develops, prompting closer evaluation of the facial nerve.

To grade the severity of the facial paralysis, many grading systems exist, such as the Terzis-Noah scale.[32] The most commonly used scale is the House-Brackmann listed below.[33] The higher the grade, the least likely full recovery will occur.

Table. The House-Brackmann Scale (Open Table in a new window)

Grade

Characteristics

I. Normal

Normal facial function in all areas

II. Mild dysfunction

 

Gross

Slight weakness noticeable on close inspection

May have slight synkinesis

At rest, normal symmetry and tone

Motion

Forehead - Moderate-to-good function

Eye - Complete closure with minimal effort

Mouth - Slight asymmetry

III. Moderate dysfunction

 

Gross

Obvious but not disfiguring difference between sides

Noticeable but not severe synkinesis, contracture, or hemifacial spasm

At rest, normal symmetry and tone

Motion

Forehead - Slight-to-moderate movement

Eye - Complete closure with effort

Mouth - Slightly weak with maximum effort

IV. Moderately severe dysfunction

 

Gross

Obvious weakness and/or disfiguring asymmetry

At rest, normal symmetry and tone

Motion

Forehead - None

Eye - Incomplete closure

Mouth - Asymmetric with maximum effort

V. Severe dysfunction

 

Gross

Only barely perceptible motion

At rest, asymmetry

Motion

Forehead - None

Eye - Incomplete closure

Mouth - Slight movement

 

VI. Total paralysis

No movement

Indications

Traumatic congenital facial nerve paralysis usually resolves spontaneously and does not require surgery. A general guideline when considering surgery in a traumatic facial paralysis patient is to determine if clinical and electrophysiologic tests reveal (1) complete unilateral paralysis (H-B grade VI), (2) evidence of temporal bone trauma based upon CT scanning and physical examination, (3) complete loss of function of the facial nerve at age 3-5 days, and (4) absence of improvement by age 5 weeks.

Surgery in patients with developmental facial paralysis is usually delayed until later in life.

Relevant Anatomy

Embryogenesis

The facial nerve (cranial nerve VII) develops early in fetal life from the facioacoustic crest in the second branchial arch. All facial muscles are identifiable in the embryo by the 14th week. The facial nerve develops close to the vestibulocochlear nerve (cranial nerve VIII). Therefore, any abnormality of these structures often accompanies facial nerve deficits. At term, the anatomy of the facial nerve approximates the adult anatomy with the exception of its superficial location within a poorly pneumatized mastoid. Development of the mastoid bone occurs from age 1-3 years and displaces the facial nerve medially and inferiorly.

Anatomy

The facial nerve is a complex mixed nerve containing motor, parasympathetic, special sensory (taste), and sensory components.

The motor nucleus lies deep within the reticular formation of the pons, where it receives input from the precentral gyrus of the motor cortex. The motor fibers innervate the muscles of facial expression, posterior belly of the digastric muscle, stylohyoid muscle, and stapedius muscle. The upper motor neuron (supranuclear) tracts supplying the upper face cross once and then cross again in the pons; thus, bilateral innervation is present, whereas tracts to the lower face cross only once.

The parasympathetic fibers originate in the superior salivatory nucleus and are responsible for lacrimation and salivation via the greater superficial petrosal nerve and the chorda tympani, respectively.

Afferent taste fibers are carried from the anterior two thirds of the tongue to the nucleus tractus solitarius via the lingual nerve, chorda tympani, and nervus intermedius.

The facial nerve also provides some sensory innervation to the external auditory canal.

The intracranial segment of the facial nerve travels 23-24 mm from the brain stem at the level of the caudal pons to the internal auditory canal (IAC). The meatal segment includes 7-8 mm of the nerve between the fundus of the IAC and the meatal foramen. The facial nerve occupies the anterior-superior quadrant within the IAC. The labyrinthine segment is 3-5 mm in length and travels superior to the cochlea and vestibule to the geniculate ganglion.

The first branch of the facial nerve, the greater superficial petrosal nerve, is within this segment. The tympanic segment is 12-13 mm in length and begins at the geniculate ganglion, where the nerve turns 40-80° posteriorly (first genu) to enter the middle ear on the medial wall of the tympanic cavity superior to the oval window and inferior to the lateral semicircular canal and ends at the pyramidal eminence.

The nerve turns inferiorly (second genu) below the horizontal semicircular canal and continues as the mastoid (vertical) portion 15-20 mm and exits the stylomastoid foramen. The extratemporal portion of the facial nerve is distal to the stylomastoid foramen and supplies the muscles of facial expression. The facial nerve divides the parotid gland into superficial and deep lobes. Within the gland, branching of the nerve is variable. Most commonly, the nerve divides into an upper temporozygomatic and lower cervicofacial division. Five terminal branches innervate the mimetic musculature of the face, namely the temporal, zygomatic, buccal, marginal mandibular, and cervical branches.

Upper motor neuron lesions of the facial nerve occur at any point from the motor cortex proximal to the facial nucleus. Clinically, upper motor neuron lesions result in muscle sparing in the upper portion of the face but involvement of the lower two thirds of the facial mimetic musculature. Lower motor neuron lesions of the facial nerve occur at the level of the facial nucleus or distal to the nucleus. These lesions involve all the motor branches, which results in total hemiparesis. Lesions near the geniculate ganglion lead to paralysis, hyperacusis, and alteration of lacrimation, salivation, and taste. Lesions distal to the greater superficial petrosal branch cause paralysis associated with alteration in taste; however, lacrimation is normal. Extracranial injuries lead to individual deficits, depending on the involved branch.[34]

 

Workup

Laboratory Studies

The workup for congenital facial paralysis does not involve any particular routine battery of lab tests. If the mother has a history of viral infection perinatally, viral titers (eg, herpes simplex virus) and a TORCH screen could be considered, but the probability of one of these infections causing a facial paralysis is low. If a neonate appears syndromic, then chromosomal analysis with technology such as florescent in situ hybridization (FISH) should be considered. In these infants with complete nerve facial palsy, an investigation for chromosome 22q11 deletions is recommended.[21] Molecular testing for CHD7 mutations may help to confirm the diagnosis and differentiate it from the 22q11.2 deletion syndrome.[35] Careful audiologic evaluation with an auditory brainstem response in these patients, and those patients with FSH MD, is advised so that a sensorineural hearing loss can be ruled out.[26]

Imaging Studies

See the list below:

  • Conventional neuroimaging does not usually contribute to the understanding the pathogenic mechanisms of congenital unilateral facial nerve palsy except in the case of a very rare large pontine lesion,[36] mastoid tumor,[37] or internal auditory canal stenosis.[38] However, congenital bilateral facial nerve palsy is usually accompanied by other congenital disorders that can be identified.[39]

  • A CT scan of the temporal bone in both axial and coronal views may be considered in infants with complete paralyses from trauma that do not resolve and, thus, surgery is being considered. A temporal bone fracture or any bony spicules within the facial canal may be demonstrated. Associated anomalies of the external ear, middle ear, inner ear, mandible, and the vertical portion of the facial nerve would suggest a developmental etiology of the paralysis.

  • An MRI study provides better definition of the nerve and the surrounding soft tissue. Aplasia or hypoplasia of the nerve may be apparent; these findings strongly suggest a developmental anomaly. In addition, a hematoma or surrounding soft tissue swelling may be present when the paralysis is associated with trauma. This may be enhanced with a 3D-CISS MRI.[39]

Other Tests

Electrophysiology tests of facial nerve function can be useful to determine the extent of nerve disruption and to assist with future surgical planning.

  • Electroneuronography (EnoG) is usually the study of choice.

    • This test involves a quantitative analysis of the extent of degeneration. It is not dependent upon the observer.

    • The summation potential is recorded.

    • If more than 90% degeneration has occurred in traumatic congenital facial paralysis consider surgical decompression. (In newborns, waiting 5 weeks is prudent.)

    • An EnoG within 48 hours of a congenital traumatic injury typically reveals normal facial nerve function, whereas, in congenital developmental paralysis, the initial EnoG reveals facial nerve function to be absent or weak because of longstanding neural degeneration or nerve absence.[10]

  • Nerve excitability test (NET)

    • This test compares current thresholds required to elicit minimal muscle contraction on the normal side with that of the weak side.

    • A difference of 3.5 µA is significant.

  • Maximal stimulation test (MST)

    • This test is similar to NET but uses maximal stimulation. It is valuable for determining the status of neuromuscular units.

    • If nerve conduction is neurapraxic, response is positive; if nerve conduction is degenerated, response is absent.

    • Sectioned nerve can still be stimulated for 24-72 hours after injury; thus, the test cannot be interpreted until 3 days later.

    • The test is graded subjectively (equal, decreased, absent).

  • Electromyography (EMG)

    • This test determines the amount of activity of muscle itself. It records motor unit potentials of voluntary and involuntary muscle contraction, as well as spontaneous muscle fiber activity.

    • Degeneration of lower motor neuron is followed by fibrillation potentials at 14-21 days.

    • Polyphasic potentials can be observed 6-12 weeks before clinical improvement.

  • Topodiagnostic studies: Not performed routinely in the workup for congenital facial paralysis.

    • Schirmer test: This test evaluates function of the greater superficial petrosal nerve (lacrimation). A reduction of more than 30% or less than 25 mm in 5 minutes is significant.

    • Stapedial reflex: If the lesion involves the nerve proximal to the branch to the stapedius muscle, the stapedius muscle does not contract and no change in impedance is evident when testing the acoustic reflex.

    • Salivary flow: Wharton papillae are cannulated, and salivary flow is measured in response to a gustatory stimulus. An abnormal result is a reduction of 25% in salivary flow compared with the noninvolved side.

 

Treatment

Medical Therapy

Immediate medical treatment of congenital facial paralysis requires attention to eye care. Instill artificial tears in the eyes of a child every hour while the child is awake. Use ointment when the child is sleeping. Care must be taken when taping the eye and using patches to prevent the eyelashes from abrading the cornea. Frequent ophthalmologic evaluations are indicated to evaluate for corneal abrasions, epiphora, and entropion.[40]

Some have recommended treating traumatic facial paralysis in the newborn with observation and corticosteroids.[2] This approach is similar to treatment of adult acute facial paralysis. No prospective randomized studies are available that evaluate the efficacy of steroid use in the newborn with facial paralysis caused by birth trauma. Steroids can be considered during the 5-week observation period before decompression or exploration of the nerve is undertaken. A recent recommendation is that corticosteroid treatment or surgery should be withheld in neonates who present with uncomplicated facial nerve resulting from forceps trauma.[41] As the child ages, speech impediments may become more obvious because of difficulty with oromotor tone; therefore, speech therapy should be considered.

Surgical Therapy

In general, more than 90% of traumatic facial nerve palsies recover spontaneously and thus surgery is not warranted;[31] no controlled study has shown an improved outcome following surgical nerve exploration and decompression. With surgery, the risk of an iatrogenic injury is high. However, surgical exploration may be considered in infants with poor prognostic factors that include a unilateral complete paralysis present at birth, hemotympanum, displaced fracture of the temporal bone, absence of voluntary and evoked motor unit response in all muscles innervated by the facial nerve by 3-5 days of life, and no improvement by 5 weeks of age.[31, 42]

Conversely, no procedures are available that can enable an infant to develop normal function of the facial nerve when the palsy is developmental in origin. Facial reanimation's goal is to minimize asymmetries and improve function. Surgical exploration in the newborn with facial paralysis is controversial. Issues regarding timing of facial rehabilitation are complex. The factors that are involved include ability of the infant to tolerate a surgical procedure, the unknown potential for recovery, and whether early surgical intervention can prevent future psychosocial problems for the child.

In addressing developmental and unresolved traumatic facial paralysis, some medical professionals advocate initial surgery during preschool to avoid the psychosocial problems associated with a physical abnormality. However, waiting until adolescence when facial growth is mature and the child is able to understand the risks and benefits of surgery also has merit.[10]

Preoperative Details

For patients with congenital facial paralysis, many surgical procedures with varying indications for patients exist.

Decompression surgery

A general preoperative guideline for decompression surgery of the temporal bone after a traumatic injury is to determine if clinical and electrophysiologic tests reveal (1) complete unilateral paralysis (H-B grade VI), (2) evidence of temporal bone trauma based upon CT scanning and physical examination, (3) complete loss of function of the facial nerve at age 3-5 days, and (4) absence of improvement by age 5 weeks. As a reminder, after the nerve had been decompressed, and if Wallerian degeneration has occurred, the nerve regenerates at a rate of approximately 1 mm per day.

Neurorrhaphy

The best situation for repair of the facial nerve is when primary reanastomosis is possible between the transected ends; however, this is an uncommon occurrence in congenital paralysis. In developmental paralysis, a fibrotic remnant of the nerve or total absence of the nerve and traumatic paralysis is often caused by a crush injury rather than transection. Nerve ends may need to be débrided before anastomosis with 8-0 or 9-0 nylon sutures. The primary recommendation today is to use an epineurial repair because suture placement with fascicular or perineurial repair is difficult and may injure the axons.[43] The key factor in neurorrhaphy is reapproximation without tension.

Cable grafts

When a tension-free primary nerve repair is not possible, such as when a segment nerve has been crushed, a cable graft may be indicated. The most common donor nerves are the greater auricular, sural, and the medial and lateral antebrachial cutaneous nerves. The ansa cervicalis has been used as a donor nerve, because some evidence exists that motor nerve grafts are better than sensory nerve grafts. Cable graft anastomosis is accomplished using 8-0 or 9-0 nylon sutures to reapproximate the epineurium. With either primary nerve repair or cable grafting, the best possible outcome is generally with House-Brackmann Grade III facial function.[44]

Cross-face grafts

This procedure offers the potential to provide specific divisional innervation to its counterpart on the contralateral face. This technique may be combined with microvascular muscle grafts. It is not applicable in some patients with developmental palsies because the distal peripheral nerve and muscle are often impaired. This has been used in patients with hemifacial microsomia. Of the 9 patients younger than 1 year, 7 had symmetry at rest and voluntary movement and spontaneous facial expression at 18 months postoperatively. As the age of the child increased, the percentage of satisfactory outcomes decreased.[45]

Nerve transposition

This procedure is indicated when no known proximal facial nerve is available based upon MRI evaluation, physical examination, and topodiagnostic studies. The hypoglossal nerve provides the best crossover graft with minimal resultant lingual atrophy as seen in the image below. Facial nerve-hypoglossal nerve grafts are not indicated in many developmental paralysis because of the impairment of the distal peripheral nerve and neuromuscular junction (may be demonstrated on muscle biopsy). An ideal outcome of this technique is good symmetry at rest, some voluntary movement with synkinesis, and mass movement; however, no emotional facial expression is expected.

Surgical photo of a XII-VII crossover with jump gr Surgical photo of a XII-VII crossover with jump graft. The great auricular nerve graft is sutured to the proximal portion of the facial nerve and to a partial sectioned hypoglossal nerve (preserving approximately two thirds of the axons going to the tongue). Image courtesy of A.D. Bruns.

Muscle transfer

This procedure is indicated when distal nerves or neuromuscular junctions are absent or when significant atrophy is present. Children often have good facial tone at rest, and the risk of the surgery must be weighed carefully against the potential benefit of muscle transfer.

The usual donor muscles for transposition flaps include the masseter and temporalis muscles. Ideal results are good symmetry at rest and some voluntary motion; however, no emotional movement is expected. The temporalis muscle can be split and used to suspend the upper and the lower face.

Mini-temporalis transposition in association with facial nerve microsurgery may be a valuable alternative to free muscle transfer in selected cases. All patients demonstrated an increase in the observers' scores after mini-temporalis transfer in comparison with the scores granted preoperatively or after neural microsurgery. Highly motivated patients committed to postoperative motor reeducation exhibited the best results.[46] Often, a combination of temporalis and masseter muscle transfers is used to rehabilitate the upper and lower face. The trigeminal nerve innervates these muscles; thus, voluntary movement can be achieved with rehabilitation training.

Facial reanimation with free neuromuscular flaps is becoming an accepted standard treatment in patients with complete unilateral facial paralysis. This has been accomplished with a 2-stage technique with the gracilis muscle; recently, a single-stage reanimation technique with the latissimus dorsi may decrease recovery time for patients.

The 2-stage technique involves placing a cross-facial nerve graft in the first stage, followed by microneurovascular muscle transfer 10-12 months later. In these cases, the sural nerve is widely used as the nerve graft, and the gracilis is the preferred donor muscle. A short nerve graft may allow the second stage to be completed in 3.5-5 months.[47] In a study by Terzis and Olivares of pediatric patients, function and symmetry improvement was observed in all patients 2 years after free-muscle transfer, with functional and aesthetic gains increasing over time. Evidence indicated that the transplanted muscles grew in harmony with the craniofacial skeleton.[48]

A single-stage facial reanimation has been used to reduce recovery time. This involves one nerve anastomosis instead of 2, with a latissimus dorsi flap and long thoracodorsal nerve anastomosed to the facial nerve on the contralateral side.[49]

A study by Veyssière et al indicated that lengthening temporalis myoplasty is an effective treatment for congenital facial paralysis. The study, which included 34 patients, found that all of the patients with acquired congenital facial paralysis (11 cases) achieved a spontaneous smile by 9.5 months postoperatively, while 92.3% of those with isolated developmental congenital facial paralysis (12 out of 13 patients) achieved a spontaneous smile by 7.3 months postoperatively, and 90% of patients with syndromic congenital facial paralysis (9 out of 10 cases) obtained a spontaneous smile by 9.7 months postoperatively.[50]

Static sling

Children often have good facial symmetry at rest and do not significantly benefit from a static sling until the skin and subcutaneous tissue have matured and relaxed. Using a fascia lata sling to suspend the lower face from the zygoma provides symmetry at rest, but no voluntary or spontaneous movement is achieved. Functional improvement of chewing, fluid retention, speech articulation, smile symmetry, and ectropion is immediate. The psychological effect is also immediate, with achievement of self-esteem and acceptance by family and peers.[51, 52]

Eye protection

When eye protection is inadequate and corneal abrasions result, tarsorrhaphy, gold weights, and palpebral springs should be considered. Gold weights are likely the best option because they are simple to insert and easily removed. This procedure is rarely performed in the newborn because parents are often very capable of protecting the infant's eyes.

A first large series of thin-profile platinum eyelid weight implantations has been introduced for the treatment of lagophthalmos. This implant significantly reduces both capsule formation phenomena and extrusion compared with gold weights and could be considered an alternative to the more conventional gold implants.[53]

Treatment for CULLP

Several options are specific to CULLP. Most parents do not notice any defect except when the child is crying; therefore, surgical intervention in the isolated CULLP deformity is rarely indicated. Surgical procedures to weaken the nonaffected side with selective marginal mandibular neurectomy or botulinum toxin injections provide symmetry at rest. Other plastic-reconstructive options include wedge resection and fascia lata sling or cheiloplasty, plication or transposition of the orbicularis oris muscle, and digastric muscle transfer.

Postoperative Details

The postoperative care of the newborn after facial rehabilitation is similar to any other surgical procedure. The child (if age appropriate) and parents should be instructed on exercises to improve facial rehabilitation.

Follow-up

After facial reanimation, return of some function has been found to occur within 18 months. Long-term treatment involves evaluating for any donor site morbidity, including tongue atrophy in patients with facial nerve–hypoglossal nerve transposition, difficulty with mastication in patients with masseter or temporalis transfer, and examination of the donor sites for greater auricular or sural nerve grafts. Routine ophthalmologic examinations and physical therapy for facial expression exercises are included in the long-term treatment of patients. As the child ages, biofeedback can be used to facilitate training of the mimetic musculature after cable grafts, facial nerve–hypoglossal nerve transposition, and muscle transfers. In children with developmental facial nerve paralysis who often have other congenital abnormalities, attention to appropriate weight gain and developmental milestones is necessary.

Complications

The complications of facial reanimation in the early postoperative period include infection, hematoma, and the production of facial paralysis on the unaffected side in the case of a cross-facial graft. Long-term complications relate to the failure of the reanimation technique and lingual atrophy when a facial nerve-hypoglossal nerve transfer has been performed.

The primary care provider should routinely observe infants with congenital facial paralysis to ensure adequate growth and development. The facial nerve is responsible for providing oral competence in the oral phase of swallowing through the orbicularis oris muscle. When deficit in innervation of this muscle is present, the infant may have great difficulty with feeding because the ability to suck is impaired. As the child ages, speech impediments may become more obvious because of difficulty with oromotor tone; therefore, speech therapy should be considered. Routine ophthalmologic examinations are also indicated to ensure that the eyes are adequately protected.

Outcome and Prognosis

More than 90% of patients with facial nerve paralysis caused by trauma recover without treatment. When the palsy is of developmental origin the parents should be informed that the child will never have an entirely normal appearance. The best outcome expected in these cases is facial symmetry at rest, near symmetry with voluntary movement, and spontaneous emotive movement.

A study by Domantovsky et al of patients with Möbius syndrome who, at mean age 13.2 years, underwent smile reconstruction with a gracilis muscle transplant (with innervation via the motor nerve to the masseter), found that at a mean follow-up of 20.4 years, improvements in muscle movement had not diminished.[54]

Future and Controversies

Much controversy exists regarding the timing of facial reanimation and the need for surgical exploration in children with congenital facial paralysis. Issues regarding the timing of reanimation are complex. Some health professionals advocate initial surgery during preschool to prevent the psychosocial aspects associated with a physical abnormality. However, waiting until adolescence when facial growth is mature and the child is able to understand the risks and benefits of surgery and participate in the decision making process also has merit.

No uniform assessment of facial function exists. The House-Brackmann scale is the most widely used, but it has only fair interrater reliability. A standardized program has been developed to permit data entry for facial function that simultaneously produces scores for each of the 6 most commonly used scales. This may progress to a method of acquiring videographs to quantify motion of relevant points of the face to provide a 3-dimensional surface scan to assist in evaluated surgical reanimation surgery.

A web-based data gathering and centralized analysis program with data and “face grams” has also been suggested because the patient population in any given program is small. This would then provide a larger pool of patient for randomized, double-blind studies to determine the effects of steroids or other treatments, thereby creating a better exchange of surgical ideas and innovations.

Other research on nerve growth will also improve clinical outcomes of facial paralysis patients in the future.[55]

 

Questions & Answers

Overview

What is congenital facial paralysis?

What is the prevalence of congenital facial paralysis?

What causes congenital facial paralysis?

What is the role of Möbius syndrome in the etiology of congenital facial paralysis?

What is the role of hemifacial microsomia in the etiology of congenital facial paralysis?

What is the role of 22q11.2 deletion syndrome (22qDS) in the etiology of congenital facial paralysis?

What is the role of Albers-Schönberg disease in the etiology of congenital facial paralysis?

What is the role of CHARGE syndrome in the etiology of congenital facial paralysis?

What is the role of facioscapulohumeral muscular dystrophy in the etiology of congenital facial paralysis?

What is the role of congenital unilateral lower lip paralysis (CULLP) in the etiology of congenital facial paralysis?

Which teratogenic medications are associated with congenital facial paralysis?

What is the focus of clinical history in the evaluation of congenital facial paralysis?

What is included in the physical exam to evaluate congenital facial paralysis?

How is congenital facial paralysis staged?

When is surgery indicated in the treatment of congenital facial paralysis?

What is the embryogenesis of congenital facial paralysis?

What is the anatomy of the facial nerves relevant to congenital facial paralysis?

Workup

What is the role of lab tests in the workup of congenital facial paralysis?

What is the role of imaging studies in the workup of congenital facial paralysis?

What is the role of electroneuronography (EnoG) in the workup of congenital facial paralysis?

What is the role of a nerve excitability test (NET) in the workup of congenital facial paralysis?

What is the role of a maximal stimulation test (MST) in the workup of congenital facial paralysis?

What is the role of EMG in the workup of congenital facial paralysis?

What is the role of topodiagnostic studies in the workup of congenital facial paralysis?

Treatment

How is congenital facial paralysis treated?

What is the role of surgery in the treatment of congenital facial paralysis?

When is decompression surgery indicated in the treatment of congenital facial paralysis?

What is the role of neurorrhaphy in the treatment of congenital facial paralysis?

What is the role of cable grafts in the treatment of congenital facial paralysis?

What is the role of cross-face grafts in the treatment of congenital facial paralysis?

What is the role of nerve transposition in the treatment of congenital facial paralysis?

What is the role of muscle transfer in the treatment of congenital facial paralysis?

What is the role of a static sling in the treatment of congenital facial paralysis?

What is the role of eye protection in the treatment of congenital facial paralysis?

How is congenital unilateral lower lip palsy (CULLP) treated?

What is included in postoperative following congenital facial paralysis reanimation surgery?

What is included in the follow-up care of congenital facial paralysis?

What are the possible complications of congenital facial paralysis treatment?

What is the prognosis of congenital facial paralysis?

What is the optimal timing of reanimation of congenital facial paralysis?

How is facial function assessed in congenital facial paralysis?