**11.2 Indirect surgical treatment**

In this technique, a vascularized tissue supplied by the external carotid artery (e.g., dura, temporalis muscle, or the superficial temporal artery itself) is placed in direct contact with the brain surface, which results in ingrowth of new blood vessels to the underlying cerebral cortex (**Figure 5**). In this technique, good cerebral blood flow is established after a few weeks and so not suitable for emergency cases [46], but good for pediatric patients with MMD because of the lower technical difficulty. The following are the options for indirect revascularization [47]:


#### **Figure 4.**

*Direct bypass procedure of superficial temporal artery (STA) and M3 branches of the middle cerebral artery (MCA) (modified from Acker et al. [44]).*

#### **Figure 5.**

*Indirect bypass procedure of indirect bypass procedure: dissected temporal muscle on the brain surface (modified from Acker et al. [44]).*
