EN - Hemifacial Spasm and Treatment

Prof. Dr. Ersin Erdoğan
Hemifacial Spasm, also known as tic convulsion, manifests itself in the form of a tic that occurs with the contraction of the muscles on one side of the face. This tic is not painful, it is disturbing and does not threaten life. It has the feature of creating stress and increases in stressful situations and can occur unexpectedly. It affects both women and men, but is still more common in middle-aged women. It is more common in Asians. The frequency of occurrence in the society is about 1 in 10,000.

Hemifacial Spasm is a neuromuscular disease, that is, it occurs with the contraction of the muscle as a result of the nerve disorder as the source. In patients, it first starts with the contraction of the eyelid and shows itself with involuntary blinking. As the disease progresses, the lower half of the face accompanies the contraction and the mouth moves to that side with the contraction. As the disease progresses, the entire face half starts to contract and continues.

Hemifacial spasm affects one side of the face (hemi means half, facial face), but in some patients it is bilateral.

What causes Hemifacial Spasm
Like trigeminal neuralgia, Hemifacial Spasm occurs as a result of irritation of the nerve for some reason. Trigeminal neuralgia is a disease of the fifth nerve
Hemifacial Spasm is a disease of the seventh nerve. Hemifacial Spasm occurs when a small artery presses on the seventh nerve (facial nerve) in the brainstem. Apart from this, it can occur due to vascular malformation, multiple sclerosis (MS) or compression by a tumor.

Symptoms of Hemifacial Spasm
The main symptom or finding is that the patient has a tic. This symptom is usually on one side of the face, but it can also be on both sides.
The symptoms that occur are as follows.
The eye closes with a small contraction in the eyelid
A more pronounced spasm causes contraction on that side of the face affecting the mouth and jaw
There may be pain behind the ear
There may be a change in hearing
Larger spasms cause contraction that spreads from the eye to the jaw across the face
Unlike trigeminal neuralgia, Hemifacial Spasm often continues during sleep.

Figure-1 The patient we operated on is a 47-year-old woman. She has had left hemifacial spasm for 6 years. Bo*ox and medication trials have been performed, but to no avail (the definitive treatment is MVD surgery). In the thin-slice MRI, there was a clearly compressed vein where the facial nerve's brainstem is located.

Twitching in the eye does not indicate that the person has Hemifacial Spasm, it can be seen very often in almost everyone, the eye contraction in Hemifacial Spasm is very severe and causes the eye to close. Hemifacial Spasm can be treated more effectively in the early stages, so early treatment is important.

Diagnosis and Treatment in Hemifacial Spasm
Hemifacial Spasm is usually diagnosed as a result of the symptoms. The characteristic tic of the disease is diagnostic. In order to investigate the cause of the patient, the patient should be evaluated by experts in the field and evaluated for vascular malformation, MS or tumor. If the patient does not have these reasons, it means that the patient has a small vessel touching the seventh nerve as the cause of Hemifacial Spasm.

The most important of the triggers is thin-section 3D MRI imaging, so it is possible to see the small vessel that is likely to be in contact. (Figure-1)The fact that the vessel cannot be seen on MRI does not rule out the possibility of vascular compression in the patient.

B*tox is used in the conservative treatment of hemifacial spasm. This drug paralyzes the contraction of the muscle in spasm and causes the spasm to resolve. This treatment is temporary and should be repeated every six months. Before starting this treatment, the patient must be scanned and other pathologies must be excluded.

The problem with B*tox treatment is that it always needs to be repeated. If we divide the treatment process into three parts, in the first part, facial paralysis occurs, and the patient may encounter problems such as asymmetry in the face, eyes not closing, and mouth not closing properly while eating, with a certain percentage of patients.

In the second part, the patient is very well. In the third part, the spasms gradually begin to recur. In other words, this treatment is not very effective in some patients and is not a definitive treatment.

Patients are not satisfied, especially because the B*tox treatment method is temporary and ineffective, and when they seek another treatment, doctors who do not apply this surgical treatment to patients who learn the "microvascular decompression" option, unfortunately, comment that the risk rate of surgery is very high and even say that there is no other treatment, you will suffer this way. In fact, the probability of a problem in experienced hands is less than 1%.

The permanent treatment method is microvascular decompression surgery, which is more frequently applied for trigeminal neuralgia. In the surgery, the vein in contact with the nerve is separated and a teflon pillow is placed in between, and the effect usually starts immediately.

Surgery in Hemifacial Spasm
The surgery performed for Hemifacial Spasm is called microvascular decompression. It is not like B*tox injection, it provides a permanent solution.

The aim of surgery is to find the vein in the brainstem that contacts the facial nerve, prevent its contact, and eliminate the cause of the spasm. Microvascular decompression is one of the highest level brain surgery procedures and should be performed by experienced teams in this field.

Surgery is performed under general anesthesia, the scalp is cut with a smaller incision made into the scalp behind the ear, the cerebellum is reached from the seventh nerve exiting the brainstem with a 1-1.5 cm diameter hole opened in the bone, the vessel in contact is separated from the nerve and a teflon pad is placed in between, and the surgery is terminated. Since the surgery is performed under a microscope using microsurgical tools and examinations, it is called microvascular decompression (Figure-2). After this surgery, the vast majority of patients

Figure-2
A picture I took from a video of a patient I operated on for Left Hemifacial spasm, showing the anatomy and surgical technique
(cranial nerves indicated by numbers)

continue their lives without spasms and medication.

All patient undergo CT Scan of the head two hours after surgery (Figure-3).

Figure-3: Recording of Teflon fragments with microvascular decompression performed behind the left ear. Abnormal Muscle Response (AMR) disappeared despite 100mAmp adaptation. When the patient woke up, the hemifacial spasm was gone. Teflon was clearly visible in the tomography performed at the 2nd hour after the surgery (Figure-2 CT image was taken at the 2nd hour after the surgery).

Some patients feel mild facial weakness after the surgery, but it is usually temporary. Some patients feel slight facial weakness after surgery, but it is usually temporary. The most serious complication is hearing loss on the surgical side and can be very rare. In the literature, this rate is around 4%, but in our own series, no unilateral total hearing loss was observed. When we add up other surgeries such as trigeminal neuralgia where MVD was performed, we have an experience of around 800 cases. The possibility of such complications is quite rare in experienced physicians in this regard, and it is important to select teams that deal with this issue. Recently, the success rate of getting rid of hemifacial spasm has increased considerably in our own series and has reached 97%. This success has been achieved both by increasing surgical experience and by using intraoperative EMG monitoring of the patient. This success has been achieved by detecting the abnormal muscle response called AMR, which is only seen in hemifacial spasm patients, with intraoperative EMG and by disappearing these AMR waves when the vessel causing the actual spasm is removed during surgery.