Objective: To emphasize the importance of adding cavernous-petrous drilling to reach the interpeduncular
cistern (IPC).
Background: Cadaveric simulation for IPC surgery is an indispensable prerequisite.
Methods: Following completion of preparatory surgical steps (orbitozygomatic craniotomies,
extradural anterior-clinoidectomies, cavernous sinus unlocking, releasing the oculomotor
and trochlear nerves via opening the porous oculomotorius and detaching tentorial
ligaments, respectively” and sylvian fissure dissections), 6 colored-injected formalin-fixed
heads (12 sides) were dissected to review the benefit of adding cavernous-petrous
(cavernous part of the petrous apex) drilling with intradural posterior clinoidectomy
to expose to the IPC. Anatomical IPC-targets (n = 10) were elected to understand the accessibility and maneuverability from the open
microscopic surgical perspective. We did not cut the PcomA to reduce miscalculation
errors. The data were collected and analyzed.
Results: Adding cavernous-petrous drilling to expose to the IPC allows reasonable visual validation
and maneuverability for all (n = 60 (10 x 6 heads)) targets (Basilar apex/trunk, 2 (ipsilateral/contralateral) posterior
communicating arteries (PcomA), 2 posterior cerebral arteries, 2 superior cerebellar
arteries, 2 oculomotor nerves, and mamillary bodies). It gives better proximal control
for both low-seated/high riding basilar apices and overcomes the tunnel-like corridor
for such deep targets. However, inevitable trigeminal nerve controlled-retraction
was done to ensure safe drilling for the cavernous-petrous apex (ophthalmic division
at risk). Besides, for right-handed surgeons, the right sided posterior clinoidectomy
and temporary aneurysm clipping to the basilar trunk were done without handshaking
(contrary, specific maneuvers with the nondominant hands caries potential risk). Trochlear
nerve injuries (n = 3) were encountered during our initial IPC manipulations on the left side [25%
(3/12) of all trochlear nerves = 5% of all targets (3/60)]. All other targets were
anatomically preserved.
Conclusion: Adding cavernous-petrous drilling for IPC approaches is promising. It provides additional
workspace. Clarifying the surgical targets and structures-at-risk benefits to the
realization of limitations and providing prospective feedback for operative theatres.
Fig. 1
