Microvascular decompression (MVD) is a highly specialized neurosurgical procedure designed to resolve persistent neurological symptoms caused by blood vessel compression of a cranial nerve. This operation involves surgically accessing the affected nerve at the base of the brainstem and placing a permanent, non-absorbable cushion between the nerve and the impinging vessel. MVD is considered a definitive treatment because it directly addresses the anatomical root cause of the disorder, aiming for long-term relief. The procedure is typically recommended when conservative medical treatments are no longer effective at controlling a patient’s severe symptoms.
Conditions Treated by MVD
Microvascular decompression is primarily indicated for conditions resulting from neurovascular compression, where a blood vessel physically irritates a nearby nerve. The most frequent indication is Trigeminal Neuralgia (TN), which causes episodes of intense, electric-shock-like facial pain, often triggered by simple actions like talking or chewing. This pain results from the continuous, pulsating pressure of an artery or vein against the trigeminal nerve, stripping away the nerve’s protective myelin sheath.
Another common target for MVD is Hemifacial Spasm (HFS), a disorder characterized by involuntary twitching and spasms on one side of the face. HFS occurs when a vessel compresses the facial nerve, leading to hyperactivity and subsequent muscle contractions. The procedure also treats Glossopharyngeal Neuralgia, which causes severe stabbing pain in the throat, tongue, ear, or tonsil area.
The MVD Surgical Process
The microvascular decompression procedure is a complex operation performed under general anesthesia, typically lasting between two and four hours. The patient is positioned on their side or back, and the head is secured to prevent movement during the delicate surgery. A small, curved incision, usually one to two inches long, is made behind the ear on the side corresponding to the patient’s symptoms.
The surgeon then performs a small opening in the skull, known as a keyhole or retromastoid craniotomy, to gain access to the area at the base of the brain. This bone opening exposes the dura mater, the thick membrane covering the brain and spinal cord. The dura is carefully opened, allowing the neurosurgeon to operate in the posterior fossa, the space containing the brainstem and cranial nerves.
Using a high-powered operating microscope, the surgeon navigates to the affected cranial nerve root zone, where the nerve exits the brainstem. The offending blood vessel, often a branch of the superior cerebellar artery or a small vein, is identified. The vessel is gently moved away from the nerve, and a small piece of non-absorbable synthetic material, such as Teflon felt or sponge, is placed as a permanent cushion between the two structures. This material ensures that the vessel’s pulsations no longer irritate the nerve. Once decompression is confirmed, the dura is closed, the bone flap or a synthetic plate is secured, and the skin incision is sutured.
Post-Operative Care and Recovery
Immediately following the procedure, the patient is transferred to a recovery room for initial monitoring and then typically to an intensive care unit or step-down unit for observation overnight. A hospital stay of two to five days is common, allowing the medical team to manage initial symptoms and monitor for post-surgical complications. Pain medication is administered to control incisional pain and headache, which are expected temporary side effects.
Nausea and dizziness are common transient issues due to the proximity of the surgical site to the balance and hearing centers of the brain. Patients are encouraged to begin light activity, such as walking, soon after surgery to promote circulation and recovery. Sutures or staples are usually removed at a follow-up appointment one to two weeks after discharge. Patients are advised to avoid strenuous activities, heavy lifting, or any activity that causes straining for approximately four to six weeks while the bone opening fully heals.
Long-Term Results and Associated Risks
Microvascular decompression offers a high probability of long-term symptom relief, particularly for Trigeminal Neuralgia. Initial success rates for immediate pain relief are reported to be between 90% and 97% for TN patients, with a majority maintaining relief years after the operation. The long-term success is attributed to the procedure’s ability to correct the underlying cause of the condition instead of masking the symptoms.
Despite the high success rates, symptom recurrence is possible over time, occurring in an estimated 15% to 20% of Trigeminal Neuralgia cases within ten years. The procedure, being a major neurosurgical operation near the brainstem, carries specific risks associated with the cranial nerves in the area. The most notable risks include temporary or permanent hearing loss, due to the proximity of the auditory nerve, and facial numbness or weakness. Other potential complications include a cerebrospinal fluid leak, infection at the surgical site, stroke, or bleeding.