The retrosigmoid intradural suprameatal approach to posterior cavernous sinus – Microsurgical anatomy

Abstract

Objective The retrosigmoid intradural suprameatal approach includes the standard retrosigmoid suboccipital route with drilling of the petrous bone above and anterior of the internal auditory meatus, allowing for exposure of the trigeminal nerve within the Meckel's cave and of the middle fossa. In this study, the authors analyzed the potential use of an extended variation of the suprameatal route to approach the posterior cavernous sinus for microsurgery of, e.g., petroclival meningiomas and trigeminal schwannomas. Methods The microsurgical anatomy of the retrosigmoid suprameatal approach was examined by using 10 adult cadaveric specimens (20 sides), using 3–40× magnification. The exposure to the posterior cavernous sinus provided by this approach was focused. Results After drilling the suprameatal tubercle toward the petrous apex, the Meckel's cave was exposed. The trochlear nerve was the landmark for opening the cavernous sinus by this approach. The dura located medially to the entry point of the trochlear nerve into the tentorium was resected, allowing exposure of the intracavernous carotid artery with its meningohypophyseal trunk. Conclusion The extended retrosigmoid intradural suprameatal approach allows exposure of the posterior cavernous sinus and may be used to remove lesions of the posterior fossa extending into the Meckel's cave and into the cavernous sinus.