Figure 2.

Craniotomy of FMD and ESCP, and dural incision after opening the dura matter and dural plasty. (a): For expansive suboccipital cranioplasty (ESCP), craniotomy is performed along the transverse and sigmoid sinuses. The foramen magnum (FMD) craniotomy is 2–3 cm in size. In FMD, the subocciptal muscle group is preserved. (b): Dural incision in both operations. (c): Opening the dura mater while preserving the arachnoid membrane. Tonsils move up after achieving appropriate decompression (white dotted arrows). Preventing blood from entering into the subarachnoid space through the pinhole by placing a sponge (white arrow) (d): Dural plasty by tightly applying Gore Tex^® (Gore Inc., Newark, DE, USA) sheet water and applying 6–8 threads on bilateral sutures and midline for tenting. OCF and C1/2 FIX. (e): Occipital–cervical fixation (OCF), occipital screws, pedicle screws at bilateral C2, and lateral mass screw at bilateral C3 as anchor screws were connected by rods. (f): C1/2 fixation by Goel’s and Harm’s method: pedicle screws at bilateral C2 and lateral mass screws at bilateral C1 as anchor screws were connected by rods.