Fig. 2

Schematic procedure for additional incision and burr-hole. a Approximately 10 cm superiorly from the eyebrow incision, further periosteal dissection was impossible due to the natural shape of the skull. b At this point, we made an additional incision. Through this additional incision, we could harvest a longer periosteal flap. c After a periosteal incision with a No. 12 blade, we pulled out the periosteal flap via the eyebrow incision. d We made a single burr-hole on the supraorbital area. Then, we inserted the pericranial flap via the intradural or extradural pathway