Download Congenital Facial Paralysis - Many Faces of Moebius Syndrome

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.)
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DiGeorge syndrome
Infectious causes of facial paralysis are:
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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 weightrelated 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 60).
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).
In unilateral paralysis the contralateral intact facial nerve can reinervate a
cross facial nerve graft and subsequently motorize the transplanted free
muscle flap. In bilateral paralysis another intact cranial nerve must be
used to innervate the muscle. My preferred choice is the Masseteric
nerve.
Two-stage Microvascular transplantation (for unilateral paralysis):
The first stage consists of identifying and mapping the contralateral facial
nerve, harvesting an adequately long nerve graft and the coaptation of
the graft onto a branch of the facial nerve.
A preauricular skin incision is performed on the contralateral side
extending slightly in the submandibular area on the neck (Fig.6). Careful
dissection anterior to the parotid will reveal the facial nerve branches.
Special attention is given to the zygomaticobuccal branches of the facial
nerve. With the help of a nerve stimulator with variable voltage and
frequency control (i.e. Stimpod-Xavant, Arrow) the nerve fibres that
create a smile on the unaffected side are identified. The aim is to select
two that perform similar movement or that at least two that their
movements overlap. This allows for one branch to be “sacrificed” for use
in the coaptation with the nerve graft.
The sural nerve is my preferred donor nerve. This is harvested in a
meticulous and atraumatic manner. The proximal end of the donor facial
nerve branch is sutured to the distal end of the sural nerve graft. The
graft is about 10-15 cm long and it is tunnelled subcutaneously in the
upper lip and banked in the upper buccal sulcus on the affected side. The
reinnervation time varies from patient to patient and it is usually around
6-9 months.
In the second stage the muscle is transplanted and its nerve coapted to
the cross facial nerve graft.
Many muscles have been described for use as functioning muscle
transfers. The latissimus dorsi and pectoralis minor are some examples.
The author’s personal preference is the gracilis muscle or a segment
thereof. (Table 1)
When reinnervation is complete (progress followed by Tinel sign) the
decision to transplant the muscle is taken. A similar preauricular incision
is performed on the affected side and a pocket is prepared in a
subcutaneous plane until the lip commissure is identified (Fig.7). The
previously banked cross facial nerve graft is also identified. A suitable
vascular pedicle is surgically prepared to accept the free flap. The facial
artery and vein are the most suitable vessels. Alternatively the large
transverse facial vein or the superficial temporal vessels may also be
used.
A second team is able to dissect the gracilis muscle and its neurovascular
pedicle simultaneously. The thigh is far enough from the face and this
allows simultaneous work without interference (Fig.8).
The distance from the oral commissure to the preauricular region is
measured and an additional 2 cm is added. This is the length of the
gracilis muscle required (Fig 9). The muscle and its neurovascular pedicle
(Fig.10) are then elevated and brought to the face. The attachment of the
muscle to the oral commissure is a very important step in the procedure.
It is inserted into the fibres of the paralyzed orbicularis oris above and
below the commissure and along the upper lip. Intraoperative traction on
the commissure and comparison with preoperative photos helps guide the
surgeon to the correct placement of the sutures (Fig.11). The muscle end
that is inserted into the face is oversewn with mattress sutures (Ethicon
Vicryl 3-0) on the commissure above and below it. (Fig. 12)
The vascular pedicle is anastomosed and the motor nerve of the muscle is
tunnelled into the upper lip where the buccal incision is reopened. The
end of the cross facial free graft and the motor nerve are coapted through
that incision.
The preoperative smile analysis is crucial in helping the surgeon decide
where the origin of the muscle should be placed. Depending on the angle
of pull desired the muscle could be sutured onto the zygomatic body, arch
or preauricular fascia (Fig.13).
Once the repair is achieved the skin flap is closed with an absorbable
suture (Ethicon Monocryl 5-0 or 6-0).
Even though movement is not expected fro another 6 months, as
described in the literature, our own experience has shown this to take
place after 6-8 weeks.
One stage microvascular transplantation (for Bilateral paralysis):
In bilateral paralysis there is no contralateral nerve to use as
reinnervation site and therefore one of the cranial nerves has to be used
instead. The two most spared in Moebius and other syndromic cases are
the V and XI. Due to the proximity of the Masseteric nerve (branch of the
trigeminus) and the fact that its use leaves no sequelae we believe it is a
more suitable reinnervation site.
The masseteric nerve courses from the superoposterior border of the
masseter muscle to the aneroinferior border in an oblique fashion. It
enters the undersurface of the muscle around 2cm below the zygomatic
arch. Within the muscle it gives off many branches. One such branch is
traced distally, transacted and reflected superiorly for coaptation with the
gracilis motor nerve.
The harvesting of the gracilis and the remaining steps of the procedure
are the same as described above.
When comparing the two procedures we conclude that:
1. Certainly in theory, the cross facial nerve graft should be the ideal
method of reconstruction because it provides fibres from the
contralateral facial nerve and hence any movement achieved in the
face should be spontaneous and synchronous with the contralateral
side.
2. Nevertheless, in children there appears to be an immense potential
of brain plasticity, which may circumvent the need for a two-stage
procedure. As indicated in figure 14 this 10 year old with Moebius
sequence, who underwent facial reanimation on the left is
demonstrating a smile without the activation of the masseter (the
mouth is open) 10 months after coaptation with the Masseteric
nerve.
3. It is our opinion and also supported by Zuker et al that the
excursion achieved with Masseteric coaptation is stronger and
resembles the natural movement with a deficit of only 2mm in its
maximal contraction.
Conclusion:
Congenital facial paralysis is an exceptionally demanding problem to treat
and should have the attention of a multidisciplinary team. This should
include a paediatric neurologist, a psychologist, a geneticist, a speech
therapist and a plastic surgeon. After consensus is reached as to the
aetiology (Traumatic or developmental) of the paralysis a precise
treatment plan should be laid down for each individual patient addressing
his/her specific needs. With careful consideration and meticulous
execution of the surgical procedures described, the unbearable burden of
facial stigma can be ameliorated and a near normal life can be expected
(Fig 15 and 16).
1. Abramson, D.L., Cohen, M.M., Mulliken, J.B. Moebius Syndrome:
classification and Grading system. Plast. Recon. Surg. 106: 961, 1998
2. Terzis, J.K., Noah, E.M., Dynamic Restoration in Moebius and MoebiusLike Patients. Plast. Recon. Surg. 111: 40, 2003
3. Ziter, F.A., Wiser, W.C., Robinson, A. Three generation of pedigree of a
Moebius syndrome variant with chromosome translocation.
Arch.Neurol. 1977;34:437.
Advantages of gracilis muscle as free flap for reanimation:
 Reliable neurovascular pedicle
 Pedicle easily dissected and prepared
 Muscle can be used as a segment
 No functional loss in the leg
 Scar easily hidden
 Two team simultaneous dissection (face and leg)
Table 1