Facial Paralysis Treatment

Between the brain and the brainstem, the fibres that will form the facial nerve arrive in a complex manner. This part relates more to neurology. After the brainstem, the facial nerve follows a winding course. It passes through the internal auditory canal, travels around the middle ear and exits through its canal in the skull base. It then emerges into the deep soft tissue plane at the level of the earlobe. It passes between the superficial and deep parts of the parotid salivary gland and, after the front part of the gland, becomes quite superficial as it extends towards the facial muscles. Within the parotid salivary gland, located just in front of the ear, the nerve divides into two main branches. These branches then divide into many sub-branches. It has been shown that the facial nerve classically has 5 separate branches (fronto-temporal, zygomatic, buccal, marginal mandibular, cervical) and numerous connections between these branches.

The temporal branch of the nerve consists of 3-4 separate branches and runs over the cheekbone, 3 cm lateral to the outer orbital rim, towards the temporofrontal region. In this region the nerve lies in a superficial plane, just beneath the skin. The upper 2 branches of the nerve stimulate the frontalis muscle and the 1-2 lower branches stimulate the orbicularis oculi muscle.

The zygomatico-buccal part consists of 5-8 branches. There are numerous connections between these branches. The branches stimulate the lip elevator muscles and the buccinator, the orbicularis oris and the lower part of the orbicularis oculi.

After separating from the facial nerve, the marginal mandibular nerve runs upwards from the middle of the distance between the mental protuberance and the ramus and passes over the facial artery and vein.

The cervical branch consists of a single branch and descends directly below the mandibular angle to stimulate the upper part of the platysma muscle.

In addition, the branches of the facial nerve also provide the secretion of the tear gland, the secretion of the salivary glands under the jaw and the functioning of the taste cells of the tongue.

Facial paralysis is divided into two main groups: congenital and acquired. It is possible to divide these groups into two subgroups: unilateral and bilateral.

Congenital facial paralysis may appear as involvement of only the facial nerve and the muscle group it supplies, or as part of a syndrome. Purely congenital facial nerve paralysis can be seen in three different forms: facial paralysis affecting the whole face (panfacial), with involvement of all branches of the facial nerve (the most common); involvement of only the lower jaw branch (the mandibular branch) (the second most common); or involvement of only the lip branch (the buccal branch).

In syndromic facial nerve paralysis, facial paralysis is seen together with other anomalies. The most common unilateral syndromic facial paralysis is “hemifacial microsomia”. The most common bilateral type is “Möbius” syndrome. In this syndrome, facial paralysis is accompanied in particular by anomalies of the hands and feet (talipes equinovarus, Poland syndrome). In Möbius syndrome, nerve involvement is severe, but the function of the muscles in the lower part of the face (in the region of the mandibular and cervical branches) is partially preserved.

Acquired facial paralysis, that is, paralysis that develops later, may be unilateral or bilateral. The paralysis may be due to intracranial or extracranial nerve damage or to muscle damage. In adults, trauma is among the most common causes. Among these, assault with a sharp or penetrating instrument, traffic accident injuries and falls from a height are the most frequently encountered traumas. Bilateral acquired facial paralysis generally occurs following skull base fractures, due to lesions involving the brainstem and due to surgery performed inside the skull.

Facial paralysis can develop due to many diseases between the brain and the brainstem or in the section from the brainstem to the facial muscles. Causes of facial paralysis between the brain and the brainstem are generally related to cerebral haemorrhage and are examined by the neurology department. Facial paralysis arising from these causes is called central facial paralysis. Facial paralysis arising from diseases of the facial nerve after the brainstem is called peripheral facial paralysis. There are many causes that can produce peripheral facial paralysis:

• Bell's Palsy: This is the most common cause of facial paralysis. Its cause is in fact not certain. It is thought that inflammation develops in a section of the facial nerve around the inner ear. Exposure to cold and wind is known to play a role. There is no finding other than loss of function of the nerve. The diagnosis is made by the absence of other neurological findings. It usually heals completely.
• Ramsay Hunt Syndrome: This is a disease caused by viruses. In addition to the findings in Bell's palsy, there is pain and there are some lesions in the external ear canal. The rate of complete recovery is somewhat lower than in Bell's palsy.
• Middle Ear Infections: Acute middle ear infection in children and chronic middle ear infection in adults can reach the facial nerve, by eroding the surrounding bone or through existing openings, and cause facial paralysis.
• Systemic Diseases: Diseases that also concern other parts of the body, such as diabetes, hypertension, neuritis (nerve inflammation) and vitamin deficiency.
• Tumoural Diseases: Tumours in the facial nerve itself or in the regions it passes through along its course can also cause facial paralysis. These may be benign or malignant. Since the facial nerve also passes through the salivary gland in front of the ear before reaching the muscles, tumours of this salivary gland can also cause facial paralysis.
• Trauma: Trauma to the area around the ear or to the face (such as blows or cuts) can damage the facial nerve and cause facial paralysis.
• Operations: The facial nerve can be injured during operations performed for other reasons inside the skull, in the ear or in the salivary gland.

The most obvious sign that the facial nerve is not working is the reduction or loss of facial movements. Movements such as raising the eyebrows, closing the eyes, showing the teeth, smiling and puffing out the cheeks are impaired. Apart from this, there may also be findings such as reduced tears, reduced saliva secretion, impaired sense of taste and increased sensitivity to noise. Additional findings may be seen depending on the underlying cause of the facial paralysis.

Taking a detailed history and a careful examination reveal the type of paralysis and the affected muscles. In the history, complaints related to the eyes in particular need to be brought to light. Asking about dry eyes, excessive tearing, excessive discomfort outdoors and the use of artificial tears are important points. In the patient's history, whether the symptoms have resolved or remained unchanged over time is important. The patient is also evaluated in terms of speech, adequacy of mouth closure and patency of the nasal airway. The patient's psychosocial state is very important for treatment planning.

The evaluation begins with the muscles. The position of the muscles at rest, their symmetry and their movements should be reviewed. The upper visual field may be restricted because of ptotic muscles. In Bell's palsy, the most common cause of facial paralysis, there are no other findings.

A very careful examination of the eyes is needed. Visual acuity, lagophthalmos, the palpebral fissure width and the presence of the “Bell” reflex should be determined. Laxity of the lower eyelid is evaluated with the “snap” test: when the lower eyelid is pulled away from the globe and released, it snaps back onto the globe with a distinct sound; this sound is not heard with a paralysed eyelid.

The nasal airways are evaluated with forceful inspiration; collapse of the nasal ala may be seen on the paralysed side. Examination of the nasal cavities is also important.

In the examination of the mouth and lips, the state of the soft tissues, mouth closure and speech should be reviewed. The corner of the mouth, the nasolabial fold and the philtrum need to be evaluated and recorded at rest and during active movements.

In some patients, two or more muscle groups may work together involuntarily (synkinesis).

Patients for whom surgery is planned in particular need to be evaluated before the operation with tests called electrophysiological tests, which show the nerve conduction velocity or the percentage of the nerve that is affected.

In addition, the patient will benefit from computed tomography or magnetic resonance imaging if intracranial or salivary gland tumours are suspected, from hearing tests if an ear-related problem is considered, and from testing the amount of tears if the tear glands are thought to be affected.

The patient's expectations should be kept in mind in treatment planning. For some patients, symmetry at rest is more important than function. For elderly patients, brow ptosis, sagging of the facial soft tissues and ectropion are more important than appearance.

For the eyes, the aims of treatment, in order of importance, are protecting the eyes, providing near-normal eyelid function, and symmetry.

For the mouth, these aims are symmetry at rest, adequate mouth closure, improvement in speech and a symmetrical smile.

When discussing the treatment plan with the patient, it must always be explained that it is not possible to achieve the targeted ideal results completely and that it is impossible to provide 100% symmetry and function.

Such treatments are applied especially to protect the eyes. Conservative treatment is applied while awaiting surgery or in patients showing recovery after nerve damage. Artificial tears and, for the night, longer-acting eye ointments and gel-form medicines, taping of the eyelids during sleep and moisture-retaining eye shields are used to prevent the cornea from drying out. In some cases, the eyelids are temporarily joined with stitches (tarsorrhaphy).

In patients with facial paralysis, activating the facial muscles with electromyography prevents muscle atrophy. Neuromuscular exercises under the supervision of a specialist therapist strengthen the partially working muscles and help them achieve better function.

In choosing the surgical method, the patient's age, the duration of the paralysis, the state of the facial muscles and soft tissues, and the availability of existing muscle or nerve donor sites are points to be taken into account.

There are three basic methods for correcting brow ptosis: brow lift by removing tissue from the forehead area, open brow lift (static suspension) and endoscopic brow lift.

The methods preferred for closing the upper eyelid are gold implant, spring, temporalis muscle-fascia transplantation and tarsorrhaphy.

Gold implant placement is both an effective and a simple method. In addition, some other methods, such as placing a magnet or silicone band in the upper and lower eyelids, can also be used. In temporalis muscle transplantation, a thin strip is raised from the temporalis muscle and its deep fascia and brought through the subcutaneous plane to the level of the upper eyelid, and the fascia is sutured to the inner canthus. The upper eyelid closes when the muscle contracts. Although tarsorrhaphy was the standard method used in the past, recently it is rarely preferred except in cases of severe corneal exposure, a damaged cornea or when other methods are insufficient.

The methods chosen here are static tendon suspension, lateral canthoplasty, lid shortening, temporalis muscle transplantation and cartilage graft.

Many patients with facial paralysis seek treatment to correct the asymmetry at rest or the excessive difference that appears when smiling. In addition, with paralysis of the cheek muscles the patient has to struggle with many problems such as impaired mouth closure, constantly biting the cheek and food collecting on the paralysed side. Both the surgeon and the patient need to define their expectations clearly. For a patient who seeks only symmetry, static suspensions or simple interventions on the soft tissue may be sufficient. For a patient who wants facial expressions restored as far as possible, more detailed interventions are needed. The only available surgical technique for providing voluntary and involuntary movements and symmetry at rest and in motion is free functional muscle transfer and nerve grafting. Because the facial muscles are numerous and have a complex function during facial expressions, no surgical intervention can restore these functions completely.

Many muscles can be used in free muscle transfer. The nerves that can be used for nerve repair may also vary according to the situation. In many methods, the ends of the facial nerve branches on the same side or the opposite side are used. However, in bilateral loss of facial nerve function, such as “Möbius” syndrome, other cranial nerves (the 5th cranial nerve) can be used. In situations like this, the patient needs to get used to making movements other than normal facial expression in order to activate the muscle (such as clenching the teeth to smile, etc.).

The muscles that can be used in free muscle transfer vary according to the shape of the face and the desired movements. Today, the gracilis, pectoralis minor, rectus abdominis, latissimus dorsi, serratus anterior, rectus femoris, abductor hallucis and extensor carpi radialis brevis muscles are used for this purpose.

The techniques preferred for nerve repair in microvascular muscle transfer are single-stage repair or nerve reconstruction performed in two stages. In the single-stage method, suitable nerve ends on the same side or nerve ends selected from the healthy side are used for the repair. In the first stage, a nerve graft is sutured to a nerve end selected from the nerve ends on the healthy side that are involved in smiling and facial expression. The other, far end (distal end) of the nerve graft is brought to the opposite side by dissection in a suitable plane and stored at the level of the upper buccal sulcus. In the second stage, about 6 months later, a functional free muscle transfer is performed and the muscle's nerve is sutured to the end of the previously placed nerve graft.

In patients who are not suitable for free muscle transfer, muscle transfer from a nearby region can be applied.

Static suspension is applied only to provide symmetry at rest. In this method, fascia, tendon or synthetic materials can be used. Static suspension with synthetic materials is rarely preferred because of the possibility of allergic reaction. Suspensions called “happylift” or “contour thread”, which have come into use in recent years, are used for this purpose, but there is not much information about their late results. The palmaris longus, plantaris and extensor digitorum longus tendons can be used for tendon suspension.

When the marginal mandibular nerve is involved, deformities of the lower lip are prominent. In this case the most disturbing problem is the inability to lower the corner of the mouth, with a lower lip that has shifted and turned outwards. This is particularly noticeable when speaking or smiling. To correct it, methods such as hypoglossal nerve transplantation and soft tissue resection can be applied.

Applying physical therapy methods to the facial muscles does not restore function to the facial nerve. However, especially in long-lasting facial paralysis, the facial muscles weaken from immobility, and later, even if the facial nerve works, there may be facial asymmetry and loss of strength. For this reason, physical therapy, beyond the massage and gum chewing that the patient can do by themselves, is recommended.