Congenital Facial Paralysis – Facial reanimation
Professor George Psaras (Cyprus)
Plastic and Reconstructive Surgery
University of the Witwatersrand
Johannesburg – South Africa
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Introduction:
Facial paralysis is a severely debilitating condition with profound aesthetic, functional, psychological and developmental effects. Despite decades of intense investigation and research there remains a need for improving and refining current procedures in order to address the multitude of finer but incapacitating physical conditions associated with facial paralysis.
Physical Findings:
Facial paralysis in the newborn invariably leads to many unfavourable sequelae early on in life. The function of muscles vital for the protection of the eye, intelligible speech, oral continence and facial expression are lost.
The Orbicularis Oculi muscle is crucial for the adequate closure of the eyelid. It is therefore of paramount importance in protecting the cornea from drying, by spreading an even tear film from lateral to medial during the blinking process and also by facilitating a physical barrier against wind and dust. Another, often neglected function of the Orbicularis Oculi is the pump-like effect it has on the lacrimal sac and thus the effective clearance of tears. Patients with paralysis of the orbicularis Oculi leading to lagophthalmos are troubled by discomfort in the eye because of corneal exposure and dessication. Long term, this leads to corneal ulcerations and epiphora, the paradox of dry eyes and tear overflow (poor pump-like effect of the paralyzed orbicularis oculi).
The other major physical characteristics of patients with facial paralysis is related to the muscles attached to, or related to lip movement and control. These patients often have difficulty feeding, poor speech, oral incontinence, drooling and an inability to express emotion. They are unable to smile (Fig.1). This is a major concern to the patient since it directly impairs communication. Often patients with facial paralysis are treated as mentally disabled simply on the grounds of poor emotional expression!
The effects of facial paralysis on the brow are not evident until later on in life. With advancing age the weight of the paralyzed forehead causes sagging of the eyebrow obstructing upward gaze. It also creates the impression of unhappiness and anger on the part of the patient.
In addition to the physical findings mentioned above the treating physician has to pay special attention to the severe anxiety experienced by parents when they come to the realization that their newborn baby is suffering from facial paralysis. Multiple counselling sessions with a thorough explanation of the problem including possible treatment options must be undertaken as soon as a diagnosis is established.
Very often, if the paralysis happens to be partial or incomplete a diagnosis is not established by the attending paediatrician in the early days of life. The patient and his/her parents may present to the paediatrician at a later stage in life questioning the presence of facial asymmetry when the baby cries (Fig.2).
Classification and Incidence:
Congenital facial paralysis is present at birth and can be broken down into partial or complete, unilateral or bilateral and traumatic or developmental. In addition congenital (developmental) facial paralysis may be isolated with involvement of the facial nerve and its muscles only (Fig.1), or it may be part of a syndrome (Fig.3).
The incidence of congenital facial paralysis is estimated to be 1.8% of live births. The vast majority of these (78-90%) are associated with birth trauma. It is speculated that forceps delivery is associated with a large number of these traumatic facial paralyses.
Aetiology:
In a newborn with congenital facial paralysis it is very important to establish early on in life the aetiology of the paralysis and distinguish between traumatic and developmental causes, as this will determine the course of treatment for the newborn. A careful history and full body examination may reveal the causes of the paralysis but additional investigations may be necessary later in life (EMG, ENOG, Nerve Conduction Studies, CT and MRI).
Traumatic conditions are mostly related to difficult labour. Complete transection of the nerve is uncommon and therefore surgical intervention is hardly required.
The facial nerve is most susceptible at its exit from the stylomastoid foramen and in its course in the narrow vertical segment of the facial canal. Compression of the infant’s head by the sacral prominence during the birthing process can lead to transient neuropraxia. Intracranial haemorrhage on the other hand may lead to supranuclear palsy involving the upper corticobulbar pathways. A distinguishing feature of upper motor neuron injury is the preservation of the orbicularis oculi and frontalis muscles associated with paralysis of the lower facial muscles contralateral to the side of the lesion. This unusual presentation is because the lower motor neuron supplying the upper facial muscles receives upper motor neuron innervation from both sides of the cerebral cortex.
More than 90% of patients with traumatic congenital facial paralysis recover without any intervention.
Developmental paralysis may be associated with other anomalies and hence classified as syndromic. The most common unilateral syndromic facial paralysis occurs with Hemifacial Microsomia. In this condition all tissues derived from the 2nd and 3rd branchial arch may be affected. This includes the facial nerve and its associated musculature. In contrast, the most common bilateral syndromic facial paralysis occurs with Moebius Sequence (see below) (Fig.3).
Bilateral facial paralysis is often incomplete, with the lower portion of the face usually less affected than the upper part (Fig.4). This distinguishes developmental causes of congenital facial paralysis from traumatic causes, which often involve the upper and lower face equally and are often unilateral.
Other less commonly encountered syndromes are:
· Poland syndrome: it includes Moebius with congenital absence of the pectoralis muscle and possible arm and hand anomalies.
· Albers-Schoenberg disease: Ostopetrosis, a rare cause of paralysis at birth. May manifest later in childhood
· Trisomy 18 and trisomy 13
· CHARGE syndrome: Multiple cranial nerves may be involved in this condition. At least one cranial nerve is involved in 75% of cases and two or more cranial nerves are involved in 58% of cases. Of the patients who have cranial nerve involvement60% involve the VIII cranial nerve, 43% the VII and 30% involve cranial nerve IX and X. (The acronym CHARGE stands for Colobomata, Heart disease, Atresia of choanae, Retarded growth, Genital hypoplasia and Ear anomalies.)
· DiGeorge syndrome
Infectious causes of facial paralysis are:
· Poliomyelitis
· Infectious mononucleosis
· Varicella
· Acute otitis media
· Mastoiditis
· Meningitis
· Bell palsy
Moebius sequence:
In 1880 von Graefe et al. first described bilateral facial paralysis. It was not until 1888 when a neurologist from Leipzig by the name Paul Julius Moebius classified various congenital cranial nerve palsies and singled out combined VI and VII nerve paralyses. This condition came to be known as Moebius syndrome (1). At the time the syndrome was mainly characterized by the clinical features of facial and abducens paralysis and was most often diagnosed by ophthalmologists.
Recently the name was changed to Moebius Sequence since it is believed that a primary aetiological insult during pregnancy is followed by a cascade of secondary events that lead to the final clinical picture (Fig. 3 and 4).
Moebius sequence is a rare and complex congenital anomaly affecting multiple cranial nerves. A recent Dutch survey estimates the incidence of Moebius Sequence to be 0.002% of all live births whereas Zuker et al estimate it to be lower, 0.0005%.
Most authors agree that the abducens (VI) and facial (VII) nerves are involved by definition. Other cranial nerves that have been observed to be impaired include glossopharingeus (IX), vagus (X), and hypoglossus (XII). Least often involved are accessory (XI) and trigeminal (V). (2)
The aetiology of Moebius sequence is largely unknown and most cases appear to be sporadic and only a small subset appears to have a genetic origin. Numerous theories exist concerning the primary underlying pathogenesis. Moebius believed that the condition was degenerative or toxic in origin and that it involved the nuclei of the affected nerves. Theories of vascular aetiologies of the syndrome have many proponents. One such theory involves disruption of flow in the basilar artery or premature regression of the primitive trigeminal arteries. A second vascular theory is a disruption of the subclavian-artery supply that involves interruption of the embryonic blood supply. Still others view Moebius syndrome as a mesodermal dysplasia involving musculature derived from the first and second branchial arches. This theory holds that brainstem changes are secondary to retrograde atrophy of the cranial nerves. Other authors suggest that the underlying problem is an inherited congenital hypoplasia or agenesis of the cranial nerve nuclei. Approximately, only 2% of cases appear to have a genetic basis. Scattered reports by Zitter (3) Slee and Kremer independently, have described specific genetic localizations in Moebius syndrome. More reports will appear as the field of molecular biology expands. Genetic mapping, when available, will help in further defining the syndrome.
In addition to genetic predisposition, evidence suggests a toxic origin of Moebius syndrome. Recent well-conducted studies in Brazil found a strong association between Moebius sequence and prenatal use of Misoprostol, a synthetic prostaglandin E1 used primarily for the treatment of NSAIDs induced gastric ulcers. Misoprostol was self administered by mothers in Brazil as an abortifacient. Misoprostol is thought to cause an ischaemic event in the embryonic brain stem early on in gestation leading to nuclei degeneration.
Children with Moebius sequence have a varied presentation depending on the degree and number of cranial nerve involvement. In the bilateral complete form, they present with a mask-like face lacking any expression (Fig.3). Speech is often affected because of poor lip movement but also because of possible involvement of the hypoglossal nerve. Amongst other speech impairments there is difficulty pronouncing “p” and “b”. In 75% of cases the abducens nerve is also involved prohibiting these children to have lateral gaze. Asking the child to follow the examiner’s finger around the visual field can easily test this.
In Moebius sequence, facial paralysis is often incomplete and asymmetric, but it is usually bilateral. In the experience of the author, the lower face (lip depressors) is often spared (Fig.4).
Other deformities associated with Moebius sequence include lower limb anomalies (club foot) upper limb anomalies (syndactyly or brachydactyly, Poland syndrome) and malformations of the orofacial structures (cleft palate, epicanthic fold, ocular hypertelorism, microstomia). In rare cases mental retardation epilepsy and association with Klippel-Feil and Hanhart syndromes have been described.
Psychosocial issues
The psychosocial aspects of patients with facial paralysis and more specifically Moebius sequence are enormous. Their disability is associated with the lack of facial expression, an absent emotional communication and often impaired speech. Peers often perceive this handicap as mental retardation. As a consequence these children are often introverted and grow up to be reclusive personalities.
Treatment:
The treatment of congenital facial paralysis is difficult since a complete and accurate assessment of the patient cannot realistically take place before the child has reached a cooperative age. This is usually around the age of 4 years.
Treatment must be individualized but in general the aims are to protect the eye and to provide symmetry at rest and in movement.
Eye:
Non-surgical manoeuvres to protect the cornea from exposure include:
· Lid taping while sleeping
· Moisture chambers (rarely used in congenital paralysis)
· Forced blinking
· Eye patches
· Eye lubrication (Duratears ophthalmic ointment or Tears Naturale, by Alcon)
Eye drops must be applied frequently during the day since their effect lasts 45 – 120 minutes. Thicker petroleum or lanolin alcohol based eye ointments can be used at night when sleeping.
A more definitive surgical procedure may be undertaken at a later stage in life (around 3-4 years of age) and only if there is significant corneal exposure and possible danger of corneal ulceration. The procedures available to us today are:
· Gold weight
· Spring
· Magnets
· Tarsorrhaphy
The insertion of a gold weight in the upper eyelid is the most commonly performed procedure and appears to have the least complications. Preoperatively a test weight is attached to the upper lid in order to establish the correct weight required to achieve closure without weight-related problems. Prostheses are available in weighs ranging from 0.8 – 1.8 g. In my experience most commonly used weights are 1.0-1.4g. Complete closure is not always achieved because the lower lid is usually lax in congenital facial paralysis. It is sufficient that the patient has an adequate Bell phenomenon.
The gold weight is placed at the upper border of the tarsal plate and is sutured in place with non-absorbable fine material (Ethicon - Prolene 6-0).
An alternative procedure for eyelid closure is the Morel-Fatio palpebral spring, which consists of a wire loop with two arms. The patient opens his/her eyelids and thus compresses the spring, which is placed subcutaneously in the upper eyelid. As the patient relaxes the spring’s “memory” returns it to its original position and thus closes the eyelid.
In addition magnetized rods have been introduced in the upper and lower eyelids effecting closure. Unfortunately, both previously mentioned techniques, are fraught with complications and are therefore not very popular methods for eyelid closure today.
Smile Reconstruction
The main complaint of young patients with developmental facial paralysis and that of their parents is the facial asymmetry when smiling or crying and very often the ridicule from their peers. Therefore, in developmental facial paralysis the mainstay of surgical treatment revolves around the reconstruction and balancing of the muscles around the upper lip and cheek. The emphasis of surgery is centred on reconstructing a smile.
Whereas previously the patient was advised to wait until adulthood before surgical procedures like temporalis muscle and masseter muscle transposition nowadays free muscle transfer is performed in certain centres with good success. It is not possible to reconstruct all movements of the face with the mere transplantation of one muscle. Nevertheless the most requested facial expression is that of a smile and this is what we aim achieving with the procedure to be described below.
Free Muscle Transplantation:
The procedure starts with a careful assessment of the patient’s smile, if the paralysis is unilateral. The direction and strength of the unilateral smile is noted. Where around the mouth is the most force exerted? What is the position of the nasolabial fold in relation to the upper lip? Standardized photos are taken which can be used intraoperatively as an aid when deciding on the position and direction of the transplanted muscle (Fig. 5).