learn more about facial paralysis
Facial paralysis is the total or partial loss of voluntary muscular movement in one side of the face. It ́s caused by facial nerve failure, meaning that nerve signals are no longer transmitted to the principle muscles in the face.
It is clinically defined as the inability to raise your eyebrow, close your eye, smile and suffering from speech impairments, etc.
When conservative treatment has not succeeded in recovering the function of the nerve, it is possible to carry out surgical reconstruction. This fundamentally depends on the cause of the lesion and how developed the condition is.
Facial paralysis causes facial asymmetry
The most common symptoms associated with facial paralysis are varied. Before paralysis arises, patients can develop a common cold and varying degrees of pain in the facial area.
Paralysis develops in a few hours and, in some cases, can worsen in the following 24 or a maximum of 48 hours.
Facial paralysis causes facial asymmetry due to the lack of movement on one side of the face. Equally, it means that the patient is unable to smile and has difficulty closing their eye, causing problems when producing tears, and speech problems.
Additionally, someone suffering from facial paralysis is often unable to raise their eyebrow, forehead or breathe through their nose. They may also chew the inside of their cheeks, food can accumulate at the back of their mouth and they may dribble.
The motor function of the facial nerve controls the facial muscles, the scalp, the outer ear and the neck.
Voluntary control is related to human communication (verbal or not), cleaning the eyes and feeding. Involuntary control is more relevant here as it relates to facial and auditory emotional expressions.
The sensitive functions of the facial nerve include shedding tears, nasal secretions, salivation and tasting with the back section of the tongue.
There are multiple possible causes for facial nerve alterations leading to facial paralysis. Some of these causes have an internal origin, whilst others are due to external conditions,
The most common facial paralysis (in 80% of all cases) has no apparent cause (Bell's palsy).
Amongst other internal causes, are tumours, strokes or brain and vascular abnormalities. There are also Cerebellopontine angle tumours (acoustic neuroma), tumours in the middle ear, tumours at the base of the skull and parotid tumours.
Equally, certain external factors can provoke facial paralysis, for example head injuries which fracture the temporal bone, some toxic agents and metabolic diseases, viral and bacterial infections, extremely cold conditions or iatrogenesis (caused in surgical accidents).
Finally, facial paralysis can arise congenitally (Moebius Syndrome).
Complete recovering of the nerve's functioning is achieved in 80% of cases. The average time taken to do this is usually 4-6 weeks, but it can be up to 6 months for full recovery.
The most common conditions are only affected by a small degree of muscular paralysis.
Factors that worsen the prognosis are:
- Complete paralysis
- Patients who are older than 55 years old
- High Blood Pressure
After surgery, the impressive learning capacity of the brain means that it will recognise the function of the newly grafted muscle, and will incorporate it into the movements used for smiling from then on. To achieve this, the patient must undergo rehabilitation.
After the muscular transplant and nerve transferral carried out in surgical treatment for facial paralysis (connecting the facial muscle to another specific nerve which is then attached to the lesioned facial nerve), a woman's brain readapts better and they are able to recover a spontaneous smile earlier than men.
Women with complete facial paralysis which has been evolving for 3.5-5 years, regain mobility and an acceptable symmetry of the mouth when smiling. The long term post operation evaluation also shows good functional and aesthetic results.
Facial paralysis can recover itself spontaneously in some cases, especially in secondary paralyses caused by exposure to extremely cold conditions or idiopathic paralysis (Bell's palsy). It is necessary to wait a reasonable amount of time (6 months) to fully recover facial movement. Spontaneous recuperation of movement after facial paralysis frequently results in the appearance of abnormal movements (synkinesis) that, depending on the situation, can be treated by physiotherapy.
When a patient smiles, they make a small movement in the jaw bone. After surgery andthanks to the learning capacity of the brain, the grafted muscle ́s new function is recognised and will from then on be included into the movements used for smiling".