Introduction: Although most posterior circulation aneurysms are currently treated by endovascular
means, some may not be amenable to this modality. Among the surgical routes, the subtemporal
approach provides excellent exposure of the incisural space. Retraction or incision
of the tentorial edge is essential for exposure of the interpeduncular cistern and
basilar artery. We present a modified technique of tentorial incision and report our
clinical experience with this technique.
Methods: Retrospective review of patients operated on from 01/1999 to 09/2011 via an extended
subtemporal transtentorial approach for posterior circulation aneurysms. The modified
tentorial incision implies dissection of the trochlear nerve (TN) along its dural
canal to its entrance into the cavernous sinus, allowing reflection of the tentorial
flap anterolaterally, capitalizing rostrocaudal exposure. Clinical and radiological
data were reviewed.
Results: This series comprises 18 patients (21 procedures) with a mean age of 47 years. Of
the 15 symptomatic patients, 10 presented (67%) with a subarachnoid hemorrhage. Aneurysms
most frequently arose from the basilar tip (61%), were of small size (50%), and had
saccular morphology (78%). Aneurysm treatment was successful on first attempt in 90%
and after a second attempt via the same approach in 100%. Oculomotor and TN palsies
were noted postoperatively in three patients and one patient, respectively; all were
transient. No procedure-related mortality occurred.
Conclusion: We describe a modified technique of tentorial incision in which dissection of the
TN from its DC is essential. This technique optimized visibility and maneuverability
by increasing the rostrocaudal exposure obtained via the extended subtemporal transtentorial
route without significant postoperative TN deficit.
