MICROVASCULAR DECOMPRESSION FOR NEURALGIAS (MVD)

Microscopic view - Compressing blood vessel

1. TRIGEMINAL NEURALGIA

Trigeminal neuralgia is a chronic pain condition that affects the trigeminal nerve, which carries sensation from your face to your brain. If you have trigeminal neuralgia, even mild stimulation of your face, such as from brushing your teeth or putting on makeup may trigger a jolt of excruciating pain.

Trigeminal neuralgia (TN), also known as tic douloureux, is sometimes described as the most excruciating pain known to humanity. The pain typically involves the lower face and jaw, although sometimes it affects the area around the nose and above the eye. This intense, stabbing, electric shock-like pain is caused by irritation of the trigeminal nerve, which sends branches to the forehead, cheek and lower jaw. It usually is limited to one side of the face. The pain can be triggered by an action as routine and minor as brushing your teeth, eating or the wind. Attacks may begin mild and short, but if left untreated, trigeminal neuralgia can progressively worsen.

Most patients report that their pain begins spontaneously and seemingly out of nowhere.

A high-resolution, thin-slice or three-dimensional MRI can reveal if there is compression caused by a blood vessel. Newer scanning techniques can show if a vessel is pressing on the nerve and may even show the degree of compression.

Blood vessel compressing Trigeminal nerve

Blood vessel compressing Trigeminal nerve

In the beginning, it is treated with medicines. If the medicines are ineffective or has side effects, surgery (microvascular decompression) needs to be considered. It involves microsurgical exposure of the trigeminal nerve root, identification of a blood vessel that may be compressing the nerve and gentle movement of the blood vessel away from the point of compression. This surgery is done through a small opening in the skull behind the ear.

Endoscopic view - Compressing blood vessel

Endoscopic View - Trigeminal nerve decompressed

Hemifacial spasm is a disorder in which the muscles on one side of your face twitch involuntarily. Hemifacial spasm is most often caused by a blood vessel touching or pulsating against a facial nerve. It may also be caused by a facial nerve injury or a tumour. Sometimes there is no known cause. The symptoms include twitching or contracting of muscles in the face that are usually on one side of the face. They are uncontrollable and painless.

These contractions often start in the eyelid, then may progress and affect the cheek and mouth on the same side of the face. At first, hemifacial spasms come and go. But eventually, usually over the course of several months to a few years, they occur almost constantly.

A high-resolution, thin-slice or three-dimensional MRI can reveal if there is compression caused by a blood vessel. Newer scanning techniques can show if a vessel is pressing on the nerve.

2.FACIAL HEMISPASM

Blood vessel compressing facial nerve. Normal facial nerve on opposite side

Schematic representation

Vein (blue) Facial nerve (pinkish white) Artery (red)

3.SURGERY FOR TINNITUS

Tinnitus is ringing in ear without external stimulation. Tinnitus affects approximately 35 to 50 million Americans every day, with 2 to 3 million Americans severely disabled by the disorder. Sometimes, tinnitus is caused by underlying pathologies such as vestibular schwannomas or neurovascular conflicts of the vestibulocochlear nerve at the level of the brainstem, which may be treated successfully by surgery ( microvascular decompressions ) or Radiosurgery.

Below is the example of tinnitus caused by vascular compression of vestibular (8th ) nerve, which was treated successfully by surgery (MVD).

Neuromonitoring (BAER) and Facial nerve monitoring is done in such cases. BAER (Brainstem auditory evoked response) tests integrity of the hearing pathways. A BAER test can help to diagnose hearing loss and nervous system disorders, especially in new-borns, young children, and others who may not be able to participate in a standard hearing test. It is usually abnormal in cases where there is compression of the vestibular nerve.

BAER after surgery : Showing returning back of the wave from post-operative

Blood vessel (AICA) pressing on the vestibular nerve

BAER before surgery