Background: The traditional retrosigmoid (RS) approach provides limited exposure of the inferior compartment of the CPA, while radical skull base approaches are demanding and associated with significant morbidity.
Methods: This study outlines the relevant surgical anatomy and the different surgical steps of a modified retrosigmoid (MRS) approach.
Results: The MRS provides enhanced exposure of the CPA and deep vascular structures resulting from a modified RS craniotomy and limited exposure of the sigmoid sinus.
Conclusion: In selected posterior fossa lesions, this cisternal approach is a straightforward corridor that can be routinely performed as a safe alternative to radical cranial base approaches.
Keywords: Lower cranial nerves tumor; Modified retrosigmoid approach; Proximal PICA aneurysm; Skull base surgery.