Microsurgical anatomy of the medial tentorial artery of Bernasconi-Cassinari.

OBJECTIVE

In the current literature, there is a lack of detailed map of the origin, course and relationships of the medial tentorial artery (MTA) of Bernasconi-Cassinari often implicated in various diseases such as dural arteriovenous fistulas of the cranial base, stenotic lesions of the ICA, saccular infraclinoid intracavernous aneurysms and tentorial meningiomas.

METHODS

Using a colored silicone mix preparation, ten cranial bases were examined using ×3 to ×40 magnification of the surgical microscope.

RESULTS

The MTA arose as a single branch in 95% of cases from the MHT at the level of the C4 segment of the internal carotid artery. The average length of the MTA was 21.7 mm (range 20.0-23.4 mm). The average diameter of the MTA was 0.53 mm (range 0.49-0.60 mm).The MTA passed just below the lower dural ring detached from the lower margin of the anterior clinoid process. During its course, the MTA drop over the intracavernous segment of the abducens nerve twisted at its exit from the Dorello's canal and overlay the trochlear into the thickness of the free margin of the tentorium cerebelli. Vascular relationships of the MTA were venous trabeculation of the cavernous sinus, basilar plexus and branches of the inferolateral trunk. The MTA sent two terminal branches: one medial rectilinear, which pursued the initial dorsal course, and the other shorter with a lateral course, which disappeared into the lateral wall of the cavernous sinus. The medial branch of the MTA curved laterally, ramifying within the free edge of the tentorium cerebelli and anastomosing along the base of the dorsal part of the falx.

CONCLUSION

The implications of these anatomic findings for surgery or endovascular procedure are reviewed and discussed.