Posterior Clinoidectomy in the Subtemporal Transtentorial Approach for a Basilar Bifurcation Aneurysm: Technical Note.

Abstract

Although the endovascular approach has emerged as the first-choice treatment for basilar bifurcation aneurysms, there are situations where direct surgery remains necessary. Among several surgical approaches, the subtemporal transtentorial approach can be adapted for low-positioned aneurysms projecting posteriorly. Because surgeons observe the aneurysm from a lateral perspective in this approach, the posterior clinoid process does not usually obstruct the surgical field, and posterior clinoidectomy in this approach has not been reported to date. We present the first report to our knowledge on the utility of posterior clinoidectomy to expand the surgical field of the subtemporal approach in a case involving a low-positioned basilar bifurcation aneurysm where a posterior petroclinoid ligament (PPL) obstructed the operative field. A 42-year-old woman underwent neck clipping by the right subtemporal transtentorial approach for subarachnoid hemorrhage due to a ruptured low-positioned basilar bifurcation aneurysm. In this case, despite incision of the tentorium posterior to the entrance of the right trochlear nerve, the PPL hindered the procedure. Posterior clinoidectomy using an ultrasonic aspirator with downward transition of the PPL successfully expanded the surgical field, enabling safe aneurysmal neck clipping. The patient was discharged from our hospital without any neurological deficits. Even when using the subtemporal approach, the PPL could impede adequate aneurysmal exposure. Posterior clinoidectomy with downward PPL transition is an effective strategy in such cases.