Skull Base Approaches to Difficult and Complex Aneurysms

The management of cerebral aneurysms (ANs) is the most important subject in neurosurgery. Microsurgical repair of ANs is the most accurate and reliable method of treatment with a 1 to 2% low risk of morbidity in an experienced surgeon's hands. Even with very difficult or complex giant ANs, the risk will be less than 5% in the hands of an expert cerebrovascular microneurosurgeon. Unfortunately, the current trends in the world of neurosurgery are not to practice or learn how to operate or how to perform precise supermicrosurgery. Instead, surgeons tend to perform endovascular coiling procedures, which is a rather blind coiling and obliteration of the AN. A review of the literature demonstrates that the total obliteration of the AN has a 50 to 60% success rate with procedure-related morbidity in the 5 to 15% range. This presentation will encourage younger neurosurgeons to train their hands for the more secure, safe, and complete obliteration repair of the difficult ANs. In this presentation, we will demonstrate the skull base approaches and our keyhole supermicrosurgical techniques for posterior circulation ANs and proximal carotid pericavernous and intracavernous ANs. Our personal experience over the past two decades with posterior circulation aneurysms includes 186 patients: 128 regular-size ANs and 58 giant ANs. Most of the time, for basilar tip and upper basilar ANs, we perform the extradural subtemporal approach; for the difficult basilar trunk ANs, we perform a lateral total petrosectomy approach; and for the vertebral and vertebral pica aneurysms, we perform the extreme lateral transcondylar skull base approach. For pericavernous and intracavernous ANs, we use a look-down transcavernous procedure; therefore, an orbitozygomatic craniotomy is totally unnecessary. We can perform a standard pterional frontotemporal skull base approach with a combined extradural and intradural exposure. Our case series consists of 187 cases of pericavernous and intracavernous ANs, 34 paraophthalmic ANs, 18 infraclinoid and fibrous ring ANs, 24 clinoidal siphon ANs, and in addition, 105 cases of giant ANs. We will demonstrate the practical technique of skull base exposure, use of the Sonopet bone shaver, exposure of the cavernous sinus, clipping techniques, and skull base bypass techniques for the unclippable giant ANs.