There are 12 pairs of cranial nerves that emerge from the brain and brainstem. Each of these nerves is responsible for different sensations and controlling different organs of your body.
Trigeminal neuralgia and hemifacial spasm are cranial nerve disorders in which the trigeminal nerve and the facial nerve are compressed as they exit from the brainstem.
The trigeminal nerve is the 5th cranial nerve which branches to provide sensation to different parts of the face including the eyes, cheek and jaw. Trigeminal neuralgia causes pain in these regions of the face when the trigeminal nerve is compressed by a blood vessel. On rare occasions, the trigeminal nerve may be compressed due to a tumour in the brain. Patients with trigeminal neuralgia experience episodes of severe facial pain, which can be triggered by talking, chewing or touching the face.
The 7th cranial nerve is the nerve that controls the facial muscles. Hemifacial spasm is characterized by involuntary twitching of the facial muscles and eyelids. The underlying cause of this condition is abnormal compression of the facial nerve by a blood vessel.
One of the most effective treatments for neurovascular compression syndromes such as trigeminal neuralgia and hemifacial spasm is microvascular decompression surgery. This surgery entails separating the compressing blood vessel away from the affected cranial nerve. Microvascular decompression is a minimally invasive surgical technique where the affected nerve is decompressed through a very small incision located just behind the ear.
Microvascular decompression surgery is indicated when conservative therapy fails to relieve symptoms of trigeminal neuralgia or hemifacial spasms.
It is also indicated when pain recurs after a percutaneous or radiosurgery procedure.
Microvascular decompression surgery is however contraindicated in patients in poor health.
It is also not suggested to treat facial pain associated with multiple sclerosis.
Microvascular decompression is performed under the effect of general anaesthesia.
You will lie on the operating table in a semi-prone park bench position.
The area of planned incision is shaved and a 4cm incision is made behind the patient’s ear.
A craniotomy is performed by drilling a small hole in the skull.
Your surgeon makes a C-shaped opening in the lining of the brain called the dura and opens the dura.
The operating microscope is then brought into the surgical field to aid visualization of the critical structures.
Blood vessels compressing the nerve are identified and carefully moved away from the nerve. A Teflon felt is placed between the compressed nerve and the blood vessels to separate and cushion the nerve.
Upon completion, the dura is closed with a muscle graft or an artificial dural patch. The skull bone opening is covered with a titanium plate cover and is secured with tiny screws. The skin and muscles are closed and sutured.
Following the procedure, you will be transferred to an intensive care unit for close observation. Your doctor will prescribe medications to relieve the incisional pain and post-operative headache. You will be given activity instructions such as avoiding driving or lifting heavy objects. You can resume normal activities only after consulting your doctor.
Risks and complications
As with any surgery, minimally invasive microvascular decompression involves certain risks and complications. They include:
- Infection and bleeding
- Cerebrospinal fluid leakage
- Trigeminal nerve damage
- Recurrence of facial pain
- Rarely, hearing loss, stroke or death
Advantages of minimally invasive microvascular decompression surgery include:
- Small nickel sized incision
- Less blood loss
Faster recovery and healing time.