General approach to the cavernous sinus

Abstract

The initial position of the patient is as for the pterional approach [55], the patient lying supine with head fixed in the Mayfield tripoint fixator. In order to expose the fronto-temporal region on the side of the lesion in the CS, the head is rotated by about 35 degrees in the opposite direction to the lesion (Fig. 66). The skin incision curves from the ear to the intersection of the midline with the hairline whereby the concavity of the curve faces anteriorly towards the eye (Fig. 66). The skin flap together with the subcutaneous layer is pulled down frontally over the edge of the orbit and dissected to the orbital margin (Fig. 68). The muscle flap is formed by an incision in the muscle close to its attachment to the bone, running from the junction of the zygoma and the orbital margin posteriorly to the end of the exposed muscle and along its edge caudally towards the ear (Fig. 68). The insertion of the muscle is preserved on the bone whereas the lateral part of the muscle flap is elevated and fixed with hooks laterally. Using a raspatory, periosteum is detached from the orbital margin at the corner where the zygoma and the orbital margin join (Fig. 69). Trephination is carried out in three points: at the site of the junction of the zygoma and the orbit, temporally, and fronto-temporo-parietally. The trephination hole in the front is placed so as to enable the orbit and the cranium to be opened at the same time (Fig. 70). Using an electric saw, the bone is cut between the first and the second burr hole (Fig. 70). From the first burr hole a 3 cm long cut is made lateromedially. This is done as anteriorly as possible so that the remaining orbital margin is approximately 3–4 mm wide.