Applied anatomy of supraorbital keyhole approach aided with endoscope

Objective : To provide anatomic basis of the supraorbital keyhole approach. Methods : The distance from the zygomatic process and the supraorbital foraman to the structures in the skull base, the angles between the lines and the median vector were measured in 21 adult cadaver heads fixed in formalin; the characteristic of the pituitary stalk, the optic chiasma and the optic nerves were also studied. Supraorbital keyhole approach were performed in 9 fresh cadaver heads to study the exposure scope and the work scope. Results : The distance from the zygomatic process and the supraorbital foraman to the cecum foraman, the skull aperture of ipsilateral and contralateral optic canal, the ipsilateral and contralater-al anterior clinoid process, the ipsilateral and contralateral post clinoid process were obtained. The angles to the midline, the distance between the anterior margin of the optic chiasm and the tuberculum sellae, between the medial margin of the 2 optic nerves, the intracranial length of the optic nerve, the area of the intra-optic space, the length of the supraclinoid internal carotid artery were obtained. Conclusion : There is a wide working area and field of vision in the supraorbital keyhole approach. It is important to know the distance and the angle of the fatal structures during the operation.