Stroke

The role of surgery in stroke is to reduce the intracranial pressure of acute stroke or to prevent recurrent hemorrhage.

• Surgery to reduce intracranial pressure–  In the acute setting, two operations are commonly performed – the decompressive craniectomy for ischemic stroke – where a part of the skull is removed and the dural covering of the brain incised to let the brain herniate out, covered only by the skin of the scalp. This reduces the pressure inside the head and prevents damage to other structures of the brain not affected by the stroke. The piece of skull that is removed may be placed in the patient’s abdomen just under the skin and replaced at a later date.  In cases of hemorrhagic stroke, the blood clot formed within the substance of the brain is removed to reduce the intracranial pressure. Clot removal is being done through endoscopic or microsurgical techniques. If there is an excess amount of brain edema along with the presence of a blood clot, the removal of the clot may be combined with a decompressive craniectomy. 
• Surgery for intracerebral hematomas caused by cavernomas and arteriovenous malformations (AVMs)- Cavernomas and AVMs often present with intracerebral hematomas.  The treatment for each one of these is, in addition to removing the hematoma, is to remove or obliterate the offending lesion. The usual presentation of cavernomas of the cerebrum is with seizures or headaches, though a proportion of these are discovered incidentally. Cavernomas may be genetically linked, and can occur anywhere in the brain but tend to bleed more when found in the brain stem, where hemorrhage can be neurologically catastrophic (the longitudinal bundle of nerve fibres arising from the cortex of the brain as they continue through the foramen magnum and become the spinal cord and vice versa). Cavernomas invariably have to be surgically removed, something that requires a fair degree of surgical expertise, especially if situated in the brain stem. Arterio- Venous malformations are graded surgically on a number of factors including its location, size, venous drainage and proximity to an eloquent area (The Spetzler Martin Grade) before deciding the appropriate treatment. Surgical removal remains the treatment of choice in AVMs that are small, close to the surface of the brain and without deep draining veins. At times feeding arteries are embolized using onyx, cyanoacrylate granules or polyvinyl alcohol to reduce the size or obliterate the AVM.  Residual AVMs or those that are too dangerous to treat by either surgery or embolization can be treated by Stereotactic Radiosurgery- focused radiation delivered one dose to the AVM. After this process however, there is an increased risk of hemorrhage for about 2 years till complete obliteration. Aneurysms that tend occur on the feeding arteries of AVMs need to be treated either separately or during the treatment for the AVM (see later for treatment of aneurysms)
• Surgery for prevention of recurrent strokes- Surgery for the prevention of recurrence consists mainly of making sure that the arteries supplying the brain are free of narrowing caused by the deposition of cholesterol and platelets, by a procedure called carotid endarterectomy.  This is done through an incision in the front of the neck, where the extracranial carotid (the part of the carotid outside the skull) is isolated and the plaque removed. The artery is repaired and the diameter restored through the use of a patch graft. Patients who have had a transient ischemic attack or a mini stroke AND have a carotid stenosis of more than 70% are most benefited from this procedure. Asymptomatic patients with severe stenosis benefit only if the perioperative risk of stroke and death are less than 3%. The placement of stents and open up stenosed arteries have recently gained acceptance. In experienced hands, when used in the correct indications, the results of treating stenosis as a result of stenting is very good.