Is Microvascular Decompression a Brain Surgery?

Before surgery, patients are examined to determine whether their general health is sufficient to withstand the stress of major surgery and anesthesia. A one-by-three-inch section of hair behind the ear on the side affected by pain is shaved.

Microvascular decompression (MVD) surgery is done under general anesthesia (the patient sleeps during the procedure). To prevent any movement throughout the procedure, the head is fixed in a surgical clamping device.

• Once the head is in position, the surgeon performs a craniotomy (a surgery to cut a hole in the skull) right below the ear. The size of the opening is equal to or smaller than that of a half dollar. Then, the dura (the tissue layer that covers the brain) is opened.
• The surgeon uses an operating microscope to detect the cranial nerves close to the brain. They specifically look for the trigeminal nerve's root zone, which is where it joins the pons or brainstem. Often, the nerve is seen to be compressed here by arteries and veins.
• Another physician, a neurologist, or neurophysiologist, keeps an eye on a machine that continuously evaluates the adjacent auditory nerve, which runs between the entrance of the skull and the trigeminal nerve.
• The surgeon intends to locate one or more troublesome blood vessels by examining the trigeminal nerve root under the operating microscope.
• Although it is not always the case, an MRI performed before the surgery might help surgeons anticipate the area where they will likely locate the veins causing nerve compression.
• In most situations, the compressing vessel is visible to the surgeon, but occasionally, it is well hidden.
• In more than half of MVD operations, the nerve is seen to be compressed by more than one vessel. Surgeons are unable to locate or identify any compressed arteries in 10 to 15 percent of MVD procedures. In such cases, many surgeons remove portions of the sensory nerve fibers to relieve the pain without causing any serious numbness.
• When a blood vessel is discovered to be compressing the nerve, it is an artery in about two-thirds to three-quarters of the instances. This distinction is crucial because arteries must be cushioned away from the nerve rather than being cut and sealed.
• However, veins can be split by cutting them out and sealing them up, rather than being padded.
• The surgeon uses several procedures to stitch the dura and cover the skull opening once the padding is in place (in the case of arteries) or the vein has been removed.
• Although the actual repair only takes about 90 minutes, the entire MVD procedure usually takes two to four hours.

The candidates for microvascular decompression (MVD) are those who:

• Have traditional trigeminal neuralgia.
• Are fit enough to undergo surgery.
• Fail to recover or get relief from pain by using medication or other conservative treatments.

For patients with classic trigeminal neuralgia, MVD is the most successful surgical procedure. If they have nerve pain that arises because of another ailment or for no known reason (secondary or idiopathic trigeminal neuralgia), other treatment options, such as percutaneous rhizotomy or stereotactic radiosurgery, may be more successful for them.

Microvascular decompression (MVD) produces the longest-lasting pain relief:

• 90 percent of patients report early pain relief
• More than 80 percent remain pain-free even after one year
• 75 percent after three years
• 73 percent after five years

In most cases, the pain is immediately relieved. The nerve fibers are no longer compressed by the pressure of the blood vessel, and signals from the light-touch fibers stop interfering with pain-signaling fibers. Sometimes, especially in those who have experienced pain for a long period, it may take a few days or even weeks for the pain to go away.

Studies don't always make clear whether a successful MVD surgery entails no pain or it also includes patients who are much improved yet experience some discomfort.

In a prospective, long-term research conducted in 1996 at the University of Pittsburgh on 1,185 patients who had undergone MVD surgery, it was discovered that 82 percent of patients reported no pain, whereas 16 percent of patients reported at least a 75 percent reduction in pain. The remaining two percent either had no alleviation or only slight improvement.

For the first several weeks following microvascular decompression surgery, patients may feel stiffness, have headaches, and experience some pain near the incision. They may occasionally encounter one or more of the following symptoms:

• Double or blurred vision 
• Distorted hearing
• Cold sore breakout
• Nausea
• Vertigo
• Poor coordination
• Fluid in the middle ear
• Ringing in the ears

These usually pass within a few days or weeks. Other potential issues might need medical attention, which includes meningitis, cerebrospinal fluid leaks, breathing problems, and wound infections. The following are the rates of these complications:

• Infection: 1 percent
• Fluid leak: 2 percent 
• Meningitis without bacteria: 8 percent 
• Hearing loss on the surgical side: 1 percent 
• Stroke that is not fatal or cerebral bleeding: 1 percent 
• Facial paralysis/numbness: 0.5 percent
• Death: 0.2 percent

Deaths have been attributed to heart attack, stroke, pulmonary embolism, brain seizures, and cranial hemorrhage. Most of the time, facial numbness is minimal and goes away completely within a few weeks. Although it occurs occasionally, permanent facial numbness can affect any portion of the face.