• Microvascular Occlusion


    Microvascular occlusion clamps off the artery leading to an aneurysm . This prevents bleeding and rupture. Sometimes a bypass procedure is done as well, rerouting blood vessels to healthy areas of the brain. A portion of the skull is removed (called a craniotomy ) and restored during this complex, open surgery.

    Reasons for Procedure

    Microvascular occlusion often treats a brain aneurysm that has ruptured and caused damage to the artery. It will not fix damaged areas of the brain, but it can improve quality of life by stopping bleeding.
    Brain Aneurysm
    An aneurysm is a weakened blood vessel in the brain that collects blood. The bulging, blood-filled pocket can put pressure on parts of the brain, pressing on nearby nerves. This can cause symptoms or cause the blood vessel to rupture (hemorrhage).
    Copyright © Nucleus Medical Media, Inc.

    Possible Complications

    Problems from the procedure are rare, but all procedures have some risk. Your doctor will review potential problems, like:
    • Weakness
    • Numbness or tingling
    • Speech disturbances
    • Visual changes
    • Confusion, memory loss
    • Seizures
    • Infection
    • Adverse reaction to anesthesia
    • Kidney damage
    • Blood clots
    • Ruptured aneurysm during surgery
    Factors that may increase the risk of complications include:
    Discuss these risks with your doctor before the surgery.

    What to Expect

    Prior to Procedure (Non-emergency Surgery)

    Your appointment before the surgery may include:
    • Physical exam and blood tests
    • Imaging tests—ultrasound, CT scan , MRI scan , or angiogram
    • Discussion of allergies
    • Discussion of medications you are taking, including over-the-counter and herbal supplements
    • Discussion of recent illness or other conditions
    • Discussion of risks and benefits of treatment options
    Before your procedure:
    • Arrange for a ride home.
    • No food or drink after midnight the night before the procedure.
    • Discuss your medications with your doctor. You may be asked to stop taking certain medications before your procedure.
    Women should let their doctor know if they are pregnant or planning to become pregnant.


    General anesthesia will be used. It will block any pain and keep you asleep through the surgery.

    Description of the Procedure

    The nurses and doctors will connect you to monitors to watch your blood pressure, heart rate, and pulse during the procedure. A catheter will be inserted to collect urine.
    An IV will be placed in your arm for sedation and anesthesia. The nurse will shave an area of your head.
    The doctor will perform a craniotomy, removing a small section of the skull to access the brain. X-rays and microscopic viewing will help the doctor find the artery leading to the aneurysm. The doctor will clamp off the artery. A bypass procedure (re-routing blood vessels toward healthy areas of the brain) may also be done.
    The section of skull is replaced and the scalp is stitched back into place.

    Immediately After Procedure

    When the procedure is done, the catheter and IV will be removed. You will need to lie still for 6-8 hours or more. You will stay in the ICU, often for a day. Your blood pressure and other vitals will be monitored closely. You will be given medication for pain or other symptoms.

    How Long Will It Take?

    3-5 hours or more

    How Much Will It Hurt?

    Anesthesia will prevent pain during surgery. Pain and discomfort after the procedure can be managed with medications.

    Average Hospital Stay

    This complex procedure is done in a hospital setting. The usual length of stay is 4-6 days. Your doctor may choose to keep you longer if complications arise.

    Post-procedure Care

    At the Hospital
    • You will rest for several hours in the ICU.
    • Nurses will monitor your vital signs.
    During your stay, the hospital staff will take steps to reduce your chance of infection, such as:
    • Washing their hands
    • Wearing gloves or masks
    • Keeping your incisions covered.
    There are also steps you can take to reduce your chance of infection, such as:
    • Washing your hands often and reminding your healthcare providers to do the same
    • Reminding your healthcare providers to wear gloves or masks
    • Not allowing others to touch your incision
    At Home
    When you get home, you may have to adjust your activity level while you recover. This may take 3-6 weeks. Home care may include:
    • Resting when you need to
    • Caring for the wound
    • Physical or rehabilitative therapy

    Call Your Doctor

    It is important for you to monitor your recovery after you leave the hospital. Alert your doctor to any problems right away. If any of the following occur, call your doctor:
    • Any changes in physical ability, such as balance, strength, or movement
    • Any changes to mental status, such as consciousness, memory, or thinking
    • Weakness, numbness, tingling
    • Signs of infection including fever and chills
    • Redness, swelling, increasing pain, bleeding, or discharge from the incision site
    • Headache
    • Changes in vision
    • Fainting
    • Pain that cannot be controlled with the medications you've been given
    • Persistent nausea or vomiting
    • Trouble controlling your bladder and/or bowels
    • Pain, swelling, or cramping in your legs
    Call for emergency medical services right away if any of the following occurs: 
    • Seizure
    • Shortness of breath or chest pain
    • Loss of consciousness
    If you think you have an emergency, call for medical help right away.


    The Brain Aneurysm Foundation http://www.bafound.org

    National Institute of Neurological Disorders and Stroke http://www.ninds.nih.gov


    Brain Injury Association of Canada http://biac-aclc.ca

    Heart and Stroke Foundation Canada http://www.heartandstroke.ca


    Cerebral aneurysm. American Association of Neurological Surgeons website. Available at: http://www.aans.org/en/Patient%20Information/Conditions%20and%20Treatments/Cerebral%20Aneurysm.aspx. Updated August 2009. Accessed May 29, 2014.

    Cowen J, Ziewacz J, Dimick J, et al. Use of endovascular coil embolization and surgical clip occlusion for cerebral artery aneurysms. J Neurosurg. 2007;107:530-535.

    Subarachnoid hemorrhage.EBSCO DynaMed website. Available at: http://www.ebscohost.com/dynamed. Updated May 2, 2014. Accessed May 29, 2014.

    Treatment of brain aneurysms. The Aneurysm and AVM Foundation website. Available at: http://www.taafonline.org/ba%5Ftreatment.html#ba%5Fclipping. Accessed May 29, 2014.

    Williams LN, Brown RD Jr. Management of unruptured aneurysms. Neurol Clin Pract. 2013;3(2):99-108.

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