In around 70 percent of all cases of facial palsy, the cause remains unclear. The good news: this most common form of facial paralysis carries very good prospects for recovery. But what happens when the facial nerve does not fully recover?
Prof. Dr. Christopher Bohr, Director of the Department of Otorhinolaryngology at the University Hospital Regensburg, explains what treatments are available today and why time is a decisive factor in cases of severe nerve damage.
What Are the Causes of Facial Palsy?
Professor Bohr, facial paralysis can present very differently from one patient to the next. What exactly happens?
First, we need to distinguish between central and peripheral facial palsy. The facial nerve — the nervus facialis — originates in the brain. If it is damaged there, for example in the context of a stroke, we call it central paralysis. When the nerve leaves thebrain at the brainstem and is damaged further along its course, we refer to it as peripheral facial palsy.
The most common form is what we call idiopathic facial palsy — meaning we cannot identify a clear cause. It accounts for around 70 percent of all facial palsy cases. All branches of the facial nerve can be affected, and with them the entire mimic musculature on one side of the face. Severity ranges from a very mild impairment of facial expression to a complete loss of function, in which no movement is possible on the affected side.
Does this kind of paralysis give any warning beforehand?
That depends very much on the cause. Idiopathic facial palsy can develop within just a few hours. Some patients notice the changes relatively quickly, while in others the paralysis sets in during sleep — they wake up in the morning, look in the mirror, and realize that one side of their face is no longer working properly.
In the case of a stroke, the palsy occurs at the same time as the circulatory disturbance in thebrain. The same applies to traumatic injury — for example, when the nerve is damaged by a bone fracture. In these cases, it is important for us to determine whether the nerve was damaged directly by the injury or whether it was affected as a result of swelling, since this has consequences for treatment.
What other causes are possible besides stroke or injury?
In addition to idiopathic facial palsy, injuries, inflammation, and tumor-related conditions can all lead to damage of the facial nerve.
Can facial palsy affect anyone?
Yes, in principle it can occur at any age. Men and women are affected in roughly equal numbers. For idiopathic facial palsy, we see approximately 40 to 50 new cases per 100,000 inhabitants per year. Other causes — such as traumatic or tumor-related facial palsy — are considerably rarer.
Are there conditions that increase the risk?
Yes. These include, for example,diabetes mellitus. There is also an elevated risk of nerve palsy in autoimmune conditions such as multiple sclerosis.
How Is Facial Paralysis Treated?
For those affected, a suddenly paralyzed half of the face is an enormous shock. How good are the chances that the nerve will recover?
In idiopathic facial palsy, the spontaneous recovery rate is very high — which is genuinely reassuring news we can share with patients. That said, both age and the severity of the paralysis play a role.
As people age, the body's regenerative capacity — and with it the nerve's — declines. Older patients therefore have somewhat lower chances of making a full recovery. The prognosis is also less favorable in cases of complete paralysis compared to a milder form of facial palsy.
How is idiopathic facial palsy treated?
We believe that swelling within the nerve canal or irritation of the nerve may play a role. For this reason, we treat idiopathic facial palsy with systemic corticosteroids, given either as tablets or by infusion. Studies have shown that this can improve the chances of recovery.
Facial paralysis changes not only a person's facial expressions but often their entire sense of self. How significant is the psychological burden?
Depending on the severity, it can be very significant. That is why thorough patient education is especially important from the outset. Patients need to understand what to expect. If you explain, for example, that recovery can take several weeks and that the first three weeks are particularly critical for healing, they are better equipped to cope — and the disappointment is not as great when there is no visible improvement by the second day.
In cases of permanent palsy, it is important to walk patients through their options and explain what we can do to address the face both functionally and aesthetically. And sometimes patients also benefit from additional psychological support.
What Is Possible With Permanent Facial Palsy?
What can be done when the facial nerve is permanently damaged?
We have various reconstructive procedures at our disposal. These are only an option, however, when the nerve is severely or completely damaged and no adequate recovery can be expected.
Which method is appropriate depends, among other things, on the patient's age. Nerve reconstruction is less promising in older patients because the regenerative capacity of the tissue diminishes over time. In patients over approximately 75 years of age, procedures that involve connecting nerve endings and allowing them to regenerate have lower chances of success.
In such cases, static correction procedures are available. With these, we can, for example, reposition a drooping corner of the mouth or an eyebrow to a more physiological position.
And what is meant by dynamic reconstruction?
With this approach, we aim to restore movement. One option is what is known as a gracilis transplant, in which a strip of muscle along with a nerve is taken from the thigh and transplanted into the face. This is, however, a highly complex procedure and is only suitable for carefully selected patients.
Why is it so important to see a specialist early in cases of severe or permanent facial paralysis?
Because time can be a decisive factor. When the facial nerve has permanently failed, the muscles it controls no longer receive any impulses. And a muscle that is no longer stimulated begins to atrophy — that is, to waste away. This process begins essentially from the very first day of the paralysis.
The facial musculature consists in part of very small, delicatemuscles. This is evident from how nuanced our facial expressions are and how even the subtlest movements can change our appearance. Once this musculature has atrophied significantly, reactivating it later becomes very difficult. The window of opportunity for reconstruction can therefore be narrow. In cases of severe nerve damage, it is well worth consulting a specialist early to discuss the available options.
Is there a patient whose story has stayed with you?
There are many such cases, because facial paralysis can place a tremendous burden on those affected. When you succeed in helping them, the gratitude you receive in return is immense — and that naturally touches you deeply.
Just recently, the parents of a young patient sent me a video. The girl had developed meningitis at a very early age and had subsequently developed facial nerve palsy. She was still too young for a major reconstructive operation. However, to prevent the facial musculature from continuing to atrophy, we connected a nerve that supplies the chewing muscle to the facial nerve — a procedure known as a masseter nerve transfer.
About a year later, I received this video — and in it, the girl is smiling into the camera. Moments like that are, of course, especially wonderful.
