Combined Pre- and Retrosigmoid Approach for Petroclival Meningiomas with the Aid of a Rotatable Head Frame: Peri-Auricular Three-Quarter Twist-Rotation Approach: Technical Note - Fujitsu, Kazuhiko; Kitsuta, Yohichi; Takemoto, Yasunori; Matsunaga, Shigeo; Tateishi, Kensuke; Nakaji, Peter (Skull Base, 2004)