The transzygomatic approach.

We aim to describe the technical details of the transzygomatic approach to intracranial surgery. The incision begins at the level of the inferior border of the zygomatic arch, anterior to the tragus, and extends towards the contralateral pupillary line. A subgaleal and interfascial dissection is performed. Then, the zygomatic arch is vertically sectioned twice and mobilized downwards, together with the masseter muscle. Next, a fronto-temporo-sphenoidal craniotomy is performed and complete exposure of the anterior temporal dura achieved. Thus, the surgical possibilities are: (i) intradural access to the middle fossa; (ii) intradural pretemporal access to the basal cisterns; (iii) intradural transtemporal access to the insular region; and (iv) extradural access to the middle fossa. The transzygomatic approach offers excellent exposure to the floor of the middle fossa and the lateral wall of the cavernous sinus (both intradurally and extradurally). Also, combined with a pretemporal approach, it affords a good view of the interpeduncular cistern; and using a transtemporal approach, it provides good access to the insular region.

Surgical anatomy of the dural walls of the cavernous sinus.

The external structure of each cavernous sinus (CS) is made of four dural walls. The aim of this study was to describe the anatomy of the dural walls of the CS. We studied 42 adult cadaveric heads, fixed with formalin and injected with coloured silicon. The main findings were: (i) the lateral wall of the CS has two layers - the external, which is thick and pearly grey, and the internal, which is semi-transparent and containing the cranial nerves (CNs); (ii) the medial wall of the CS has two areas - sellar and sphenoidal, both made up of one dural layer only; and (iii) the superior wall of the CS is formed by three triangles - oculomotor, clinoid and carotid - CN III may be found in a cisternal space of the oculomotor triangle; and (iv) the posterior wall of the CS is made up of two dural layers - meningeal dura and periostic dura - and this wall is close to the vertical segment of CN VI.