Background: Posterior circulation revascularization is essential for complex cerebral aneurysms
that cannot be treated with endovascular interventions. Revascularization of the posterior
cerebral artery (PCA) is particularly difficult due to the deep and narrow surgical
corridor necessary for access. Several approaches have been previously proposed for
PCA revascularization, but all remain technically challenging and could cause complications.
Objective: We evaluate and assess the exposure afforded by a conventional subtemporal approach
compared with combine subtemporal perilabyrinthine approaches.
Methods: Subtemporal approaches and subtemporal approaches combined with supralabyrinthine,
supra- and retrolabyrinthine, and retrolabyrinthine pre- and retrosigmoid approaches
were performed on 5 cadaveric heads (10 sides). All of these perilabyrinthine approaches
were completed with incising of the tentorium. Exposure of the anterior and posterior
aspects of the P2 segment of the PCA and the surgical maneuverability afforded by
each approach was evaluated.
Results: The subtemporal approaches proved insufficient exposure of and surgical maneuverability
around the P2 segment due to the presence of the tentorium superiorly and mastoid
inferior. Addition of the supralabyrinthine mastoidectomy with tentorial resection
improved exposure significantly. Addition of both supra- and retrolabyrinthine mastoidectomy
offered good exposure but no clear advantage was obtained from the addition of the
retrolabyrinthine drilling. Addition of the retrolabyrinthine pre- and retrosigmoid
approach extended the surgical field inferiorly and posteriorly and expanded maneuverability.
Conclusion: The subtemporal approach alone is insufficient to adequately expose the P2 segment
of the PCA. The addition of perilabyrinthine mastoid drilling and suprameatal dissection
considerably improved exposure of the P2 segment, especially its posterior aspect.
More extensive mastoid drilling is unnecessary for revascularization.
