**11.4 The complication of the surgical revascularization**

Surgical revascularization is not risk-free. This can range from a transient increase in intracranial pressure resulting in headache, seizures, and reversible neurological deficits to perioperative stroke. The mechanism is cerebral hyperperfusion syndrome because of the revascularization-induced hyperperfusion of the area supplied by the chronically vasoconstricted blood vessels, where the autoregulation is impaired. Incidence of this phenomenon was found to be up to 47% [50].

#### **Figure 6.**

*Combined revascularization procedure. The temporal muscle is positioned on the brain surface, and the STA is a bypass graft to the M3 branch of MCA (modified from Acker et al. [44]).*

All adults and children with ischemic MMD or MMS should have aspirin for a long term. If there are no contraindication and significant ischemic symptoms, surgical revascularization is a reasonable option [47]. AHA guidelines recommend it for patients with compromised cerebrovascular perfusion according to blood flow studies [39]. As mentioned before there is no evidence for opting for direct or indirect revascularization or vice versa, though the latter is preferred in the pediatric age group. Evidence for postoperative use of aspirin is limited. In a recent retrospective study, patients treated with postoperative aspirin had better outcome [44, 51].
