Chronic subdural haematoma is characterised by a pathological collection of blood in the subdural space, and usually has an insidious onset and progression. It may begin forming several days or weeks after bleeding initially starts. Bleeding is usually caused by a head injury, which may be minor in nature.
People who are asymptomatic or have minor symptoms with smaller haematomas are usually offered conservative treatment with careful monitoring and medical management. In contrast, people who have more severe symptoms and larger haematomas, and who have acceptable surgical risks, are generally offered burr hole surgery or a craniotomy.
This procedure is done using general or local anaesthesia, under fluoroscopic guidance. A catheter is inserted into the common femoral or radial artery, and a microcatheter is then guided into the middle meningeal artery (MMA). Angiography is used to select MMA branches for embolisation and to detect collateral vessels.
If there are no significant collateral vessels, target branches are embolised. If there are significant collateral vessels, MMA embolisation may not be offered. If the procedure is offered, the collateral vessels are either occluded using coils before embolisation, or the microcatheter is advanced more distally to avoid them. Once there is no flow in the MMA target branches on angiography, the catheters are removed.
This procedure aims to eliminate the blood supply from the MMA to the membrane around the haematoma, to allow the eventual spontaneous resolution of the haematoma and to reduce the risk of recurrence.