Complications of Therapies for Moyamoya Disease in Children

Surgical

• Postoperative cortical ischemia: When the patients show focal neurologic deficits, which correspond to the surgical area, possibility of cerebral infarction and postoperative epidural or subdural hemorrhage should be ruled out by urgent neuroimaging studies. When new cerebral infarction occurs, mild elevation of blood pressure is one of the options. However, conversion to hemorrhagic infarction may happen.
• Hyperperfusion if direct revascularization (STA-MCA anastomosis): The hyperperfusion syndrome with hemorrhagic infarcts is absent in cases with indirect revascularization. However, it may occur after direct revascularization in the setting of chronic, profound brain ischemia (9,26). In these cases, hypertension should be strictly avoided (mean arterial blood pressure, within 20-30 mm Hg from preoperative level, for postoperative 7 days) as well as hypotension (26).
• Extra-axial hematomas (epidural and subdural): Because of pre-formed collaterals through the dura and the skull, epidural or subdural hematoma formation is one of the common complications. It may aggravate postoperative ischemia-related complications.
• Scalp necrosis, alopecia: Because the scalp in children is thin and the vascularized part is separated and inserted on to the brain, only less vascularized thin layer of scalp remained at the original site. Therefore, the scalp is vulnerable to necrosis or alopecia in children.
• Seizures: Seizures may occur as a manifestation of ischemia or infarction. It may aggravate the ischemia in a vicious cycle.
• Movement disorders: Rarely patients may show transient postoperative movement disorders. It usually spontaneously disappears within several months.
• Headaches: Often patients complain of new postoperative headaches. It may be a manifestation of transiently aggravated or newly developed ischemia, but also may be caused by compensatory arterial dilatation associated with postoperative continued narrowing of internal carotid, and anterior, middle and posterior arteries even though the cerebral blood flow is well preserved. Usually the response to medication is poor, although some reports have indicated utility of vasodilators, such as verapamil.