Microvascular decompression (MVD) is a procedure to relieve pressure on nerves in the brain caused by pressure from neighbouring blood vessels.
MVD is the surgical treatment for trigeminal neuralgia, hemifacial spasm and glossopharyngeal neuralgia, where other non-surgical treatment such as medication has not helped. The procedure is sometimes preferred to other approaches (e.g. percutaneous stereotactic radiofrequency rhizotomy or glycerol injection in trigeminal neuralgia as it avoids any numbness in the face and botox injections in hemifacial spasm).
Before all neurosurgical procedures, including microvascular decompression, you should…
- Stop eating or drinking anything from midnight the night before the procedure (You may take medications with very small sips of water until the operation).
- Avoid any non-steroidal anti-inflammatory medication (NSAIDs) at least one week before the procedure.
- Please tell your doctor if you are on blood thinning medications, including aspirin, Plavix, warfarin and other blood thinners. Depending on what type of medication, you may need to stop taking them several days ahead of the procedure.
- Preferably avoid dental treatment (within three weeks) or any other form of surgery (within three months) of the planned procedure.
- If you develop any symptoms of infection, e.g. a cold or flu, before surgery, or if you are receiving treatment for an infection, let our office know as soon as possible.
The procedure involves making a small (2.5cm diameter) bone window in the skull - a 'craniotomy' – just behind the ear. The surgeon opens the membrane covering the brain (‘dura mater’) and then, using the operative microscope, the trigeminal nerve is identified as it connects to the brain stem. Where a blood vessel is exerting pressure on the nerve, the blood vessel is gently separated from the nerve and a small piece of special Teflon sponge is inserted in-between to prevent any further nerve compression. Once this is complete, the bone flap is secured with titanium plates, which are screwed into position. Sometimes, bone cement is placed over the skull opening. The overlying muscles and skin of the scalp are then moved back into position and sutured together.
The procedure is conducted under general anaesthetic and normally takes 2-3 hours. Microvascular decompression is an effective treatment of trigeminal neuralgia in ~90% of cases. The same procedure is performed in hemifacial spasm and glossopharyngeal neuralgia, where the facial nerve (cranial nerve VII) and glossophargyneal nerve (cranial nerve IX) are separated from blood vessels respectively.
After surgery the patient is transferred to the intensive care unit and is generally able to return home within 2 – 3 days. It is normal to experience headache, nausea and some dizziness after the procedure. A patient that has been taking medication for trigeminal neuralgia will be able to gradually reduce this medication (and finally stop using it) after the procedure over several weeks.
Headache and general pain after leaving hospital is normal, and this can be controlled using pain control medication. You may be given stronger (narcotic) pain medication, which can taken for up to two weeks after surgery.
You should also avoid sitting for long periods of time and avoid any strenuous physical activity (including normal housework) or lifting of anything heavier than 2 kg. Light physical activity, such as walking and stretching is fine.
Avoid showering and/or using shampoo for 3-4 days after the procedure. Sutures or staples to the wound will need to be removed as directed by the neurosurgeon.
When to call a doctor
You should call a doctor if you have any of the following symptoms after surgery...
- Drowsiness, unsteadiness on your feet, lack of alertness.
- Weakness affecting the arms or legs.
- Any sign of infection (redness, swelling, pain) in the wound.
- Leakage of cerebrospinal fluid (CSF) through the wound, nose or ears.
- A temperature over 38 °C.
- Severe nausea or vomiting.
- Severe neck pain (where you cannot put your chin on your chest).
- Increase in frequency / severity of headaches.
In addition to the standard risks of all surgery (such as complications related to anaesthesia, infection, blood clot formation in legs - “DVT’s” and lungs – “Pulmonary Emboli”), the main risk associated with microvascular decompression is nerve damage. Symptoms of nerve damage include facial numbness, paralysis of facial muscles, facial droop, difficult eye closure, dysphagia (difficulties swallowing), development of a hoarse voice, loss of hearing, double vision and balance issues when walking.
Another risk is leakage of cerebrospinal fluid, which may occur in the wound, or through the ear air cells leading to dripping of clear fluid through the nose or ear.
Trigeminal neuralgia can be treated with medication or using other needle-based techniques known as 'percutaneous radiofrequency ablation’, ‘balloon rhizotomy' and 'glycerol injection'. These approaches can cause ongoing facial numbness. Another treatment option is stereotactic radiosurgery (SRS).