Fig. 3
Illustrations of external carotid artery (ECA) branches involved in direct revascularization after side-side (S-S) bypasses. A preoperative digital subtraction angiography (DSA) from patient 1 showed the superficial temporal artery (STA) parietal (red arrows) and frontal (yellow arrows) branches, there was no obvious anastomosis between the two arteries. After S-S bypass, the DSA at postoperative 3 months showed the enlarged STA frontal branch (yellow thick arrows) contributed in the postoperative revascularization through the reserved distal end of STA parietal branch. Red dotted circle indicted the anastomosis site, blue arrow head indicated the filling of recipient artery, white dotted ring indicated the revascularization area; B, patient 2’s DSA showed obviously preoperative spontaneous anastomosis (white arrows) between the STA parietal branch (red arrows) and the occipital artery (OA) (green arrows) in scalp. 5 months after the S-S bypass (red dotted circle indicted the anastomosis site), the OA was enlarged and participated in postoperative revascularization via the reserved distal end of STA parietal branch, and archived moderate effect (green dotted oval). Blue arrow head indicated the filling of recipient artery; C, preoperative DSA from patient 3 showed no connection between the STA (red arrow) and OA (green arrow). 6 months after S-S bypass, spontaneous anastomoses (white arrows) were formed between the OA and distal donor STA, thus let OA flow entered the intracranial (white dotted oval); D, DSA at postoperative 12 months from patient 4 illustrated the co-participating of OA (green arrows) and STA frontal branch (yellow arrows) in postoperative revascularization (white dotted oval), although the STA parietal branch (red arrow) seemed weak even before surgery, the OA and STA frontal branch played the backup roles to direct revascularization and avoided the occurrence of complete no revascularization effect.
