What Happens During Microvascular Decompression Surgery for Hemifacial Spasm?
While hemifacial spasm is not life-threatening, it can significantly impair a person's quality of life and self-confidence. Left untreated, the condition tends to persist indefinitely and often worsens over time. In severe cases, chronic muscle twitching may even lead to facial muscle atrophy. Early intervention is crucial, and among the most effective treatments available, microvascular decompression (MVD) surgery stands out as a long-term solution for eligible patients.
Understanding Hemifacial Spasm and Surgical Intervention
Hemifacial spasm typically begins with involuntary twitching on one side of the face, usually around the eye, and gradually spreads to involve the lower facial muscles. This occurs when a blood vessel compresses the facial nerve near the brainstem, causing abnormal signaling. While medications and Botox injections offer temporary relief, only MVD surgery addresses the root anatomical cause—making it the preferred option for those seeking a permanent resolution.
Step 1: Preparing the Surgical Site
Prior to the procedure, medical staff will shave a small section behind the patient's ear to ensure clear access to the surgical area. This step is minimally invasive and typically involves removing hair within a 5–6 cm radius. For individuals with short hair, especially men, this change is barely noticeable post-surgery, and hair regrowth usually begins within a few weeks. The discreet location ensures that any scarring remains hidden by natural hair growth.
Step 2: Making a Small Incision Behind the Ear
The surgeon makes a small incision—typically about 4 centimeters long—just behind the ear in the mastoid region. A horizontal incision is generally preferred due to its smaller size and reduced disruption of surrounding tissues. Unlike vertical cuts, which may require more extensive muscle retraction, horizontal approaches minimize trauma and support faster healing. This strategic placement also allows for excellent cosmetic outcomes, as the scar becomes nearly invisible once healed and covered by hair.
Step 3: Creating a Temporary Bone Window
After carefully moving aside the soft tissue, the surgeon exposes the occipital bone at the base of the skull. Using precision drills, tiny burr holes are created in the bone. Then, a small circular piece of bone—roughly the size of a quarter (about 1–1.5 cm in diameter)—is gently removed to form a "craniotomy window." This opening provides direct access to the cerebellopontine angle, where the facial nerve exits the brainstem. Once the procedure is complete, this bone fragment is replaced and secured, preserving the integrity of the skull structure.
Navigating the Brain's Delicate Anatomy
The human brain houses 12 pairs of cranial nerves, each with distinct pathways and functions. Identifying the correct nerve amidst this complex network demands both advanced imaging and surgical expertise. Prior to surgery, high-resolution MRI scans help pinpoint the exact location where a blood vessel—often the anterior inferior cerebellar artery (AICA) or a branch of the vertebral artery—is compressing the facial nerve. During the operation, neurosurgeons use high-powered operating microscopes to visualize these delicate structures in real time.
Step 4: Locating the Offending Vessel and Facial Nerve
Once the surgical field is exposed, the neurosurgeon meticulously traces the course of the facial nerve (cranial nerve VII). Because nerves are elastic, simply lifting the compressing vessel away—even if successful during surgery—won't guarantee lasting results; once the instrument is removed, pulsations from the artery can push the vessel back into contact with the nerve, leading to symptom recurrence. Therefore, passive separation isn't enough—stable, long-term insulation is required.
Step 5: Inserting a Protective Teflon Padding
To prevent recurrent compression, surgeons insert one to three ultra-soft, biocompatible pads made of Teflon (polytetrafluoroethylene) between the offending blood vessel and the facial nerve. These sponge-like implants act as shock absorbers, dampening the pulsatile forces transmitted from the artery. Much like a mediator stepping between two arguing parties, the Teflon pad maintains a physical barrier that prevents direct contact while allowing both structures to function normally. The material is non-absorbable, inert, and highly stable, meaning it won't degrade or shift position over time—offering durable protection against relapse.
Completion and Recovery
After confirming proper placement and stability of the padding, the surgeon replaces the small bone flap and secures it with tiny plates or sutures. The underlying tissues are then layered back into place, and the skin incision is closed with sutures or staples. Most patients remain hospitalized for 2–4 days following the procedure for monitoring and recovery. Many report immediate or gradual improvement in twitching, with full resolution often occurring within weeks to months.
Microvascular decompression offers a high success rate—over 85% of patients experience significant or complete relief—with low complication risks when performed by experienced teams. As a definitive treatment targeting the underlying cause, MVD remains the gold standard for managing persistent hemifacial spasm and restoring normal facial function and confidence.