Merging Cavernous and Meckel’s Petrous Drilling with Extended Kawase’s Approach and Upper Hemiclivectomy (CMK-UHC) Create Reasonable Accessibility/Maneuverability to the Center of the Skull Base

Background: The petrous apex is composed of cavernous, Meckel’s, and Kawase’s parts (CMK).

Objective: To accentuate the value of adding cavernous and Meckel’s petrous drilling with extended Kawase’s approach and upper hemiclivectomy (CMK-UHC) to access the center-of-the-skull-base (CSB).

Methods: Succeeding accomplishment of preparatory phases (cavernous sinus unlocking, liberating the ophthalmic/oculomotor/trochlear nerves, sylvian fissure dissections, and securing petrous/cavernous carotid), 6 colored-embalmed-heads (12 sides) were dissected to analyze the advantage of adding stepwise CMK drilling with UHC to expose CSB. Anatomical CSB-targets [(n = 18/side) (basilar apex/trunk, 2 (ipsilateral/contralateral) posterior communicating arteries, 2 posterior cerebral arteries, 2 superior cerebellar arteries, 2 oculomotor nerves, mamillary bodies, stalk/pituitary/diaphragma-sellae, 2 abducent nerves, ipsilateral trigeminal nerve, ipsilateral facial/vestibulocochlear nerves, ipsilateral anterior inferior cerebellar artery, ipsilateral lower cranial nerves, and ipsilateral vertebral artery)] were elected to understand the accessibility/maneuverability.

Results: Combined CMK-UHC approach to CSB permits reasonable visual validation/maneuverability for all (n = 216 (18 × 6 heads × 2-sides)] targets. It grants better proximal control for both low-seated/high-riding basilar apices, overcomes the restrictions of limited petrous drilling, and augments the petroclival exposure. Still, to warrant safe drilling for the cavernous Meckel’s petrous apex, the inevitable neural manipulation puts the pertinent nerves at risk. Injuries to the medial fibers of the ophthalmic-gasserian junction occurred in 33.3% (4/12) = [1.8% of all targets (4/216)]. All abducent nerves were released and anatomically preserved. The dominant-hand CMK-UHC drilling and temporary aneurysm clipping to the basilar trunk were done without handshaking (contrary, non-dominant hands “carries risk”). Trochlear nerve injuries (n = 3) were encountered during our initial CSB manipulations with non-dominant hands [25% (3/12) = (1.4% of all targets (3/216)]. All other targets were anatomically preserved. Hurts might be attributed to the learning curve.

Conclusion: Combined CMK-UHC approach for CSB is promising. Clarifying the surgical targets and structures-at-risk promotes the realization of limitations and provides prospective feedback for operative theaters.

Publication History

Article published online:
05 February 2024

• References

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