Fig. 1

The surgical procedure of STA-MCA bypass. A The frontal and parietal branches of the STA were separated. B The parietal branch (donor vessel) was stained by methylene blue. C The M4 segment of the MCA (recipient vessel) was blocked by two temporary aneurysm clips and the vessel wall was cut. D The donor and recipient vessels were anastomosed end to side. E and F Each side of the vessels was sutured with 3–4 needles. G One aneurysm clip was released and there was no bleeding at the anastomotic site. H The blood reflux of frontal branch was well