Posterior Fossa Aneurysms

Abstract

Object. The authors report on the surgical results they achieved in caring for patients with vertebral artery-posterior inferior cerebellar artery (VA-PICA) saccular aneurysms that were treated via either the transcondylar fossa (supracondylar transjugular tubercle) approach or the transcondylar approach. In this report they clarify the characteristics of and differences between these two lateral skull base approaches. They also present the techniques they used in performing the transcondylar fossa approach, especially the maneuver used to remove the jugular tubercle extradurally without injuring the atlantooccipital joint. Methods, Eight patients underwent surgery for VA-PICA saccular aneurysms (six ruptured and two unruptured ones) during which one of the two approaches was performed. Clinical data including neurological and radiological findings and reports of the operative procedures were analyzed. The Glasgow Outcome Scale was used to estimate the activities of daily living experienced by the patients. In all cases the aneurysm was successfully clipped and no permanent neurological deficits remained, except for one case of severe vasospasm. In seven of the eight patients, the transcondylar fossa approach provided a sufficient operative field for clipping the aneurysm without difficulty. In the remaining patient, in whom the aneurysm was located at the midline on the clivus at the level of the hypoglossal canal, the aneurysm could not be found by using the transcondylar fossa approach; thus, the route was changed to the transcondylar approach, and clipping was performed below the hypoglossal nerve rootlets. Conclusions. Both approaches offer excellent visualization and a wide working field, with ready access to the lesion. This remarkably reduces the risk of development of postoperative deficits. These approaches should be used properly: the transcondylar fossa approach is indicated for aneurysms located above the hypoglossal canal and the transcondylar approach is indicated for those located below it.