====== Basilar bifurcation aneurysm surgery ======

[[Basilar bifurcation aneurysm]] were considered inoperable until [[Charles George Drake]] reported 4 cases in [[1961]]
((Drake CG. Bleeding Aneurysms of the Basilar Artery: Direct Surgical Management in Four Cases. J Neurosurg. 1961; 18:230–238))
, with larger series reported later
((Drake CG. Further Experience with Surgical Treatment of Aneurysms of the Basilar Artery. J Neurosurg. 1968; 29:372–392)).

Anatomical factors such as size and projection of the [[aneurysm]], distance between the [[aneurysm neck]] and the [[dorsum sellae]], and location of the basilar bifurcation contribute to surgical complexity
((Wainberg RC, da Costa MDS, Marchiori M, Soder RB, de Campos Filho JM, Netto
HLD, Neto EP, Chaddad-Neto F. Microsurgical Clipping of Low-Riding Basilar
Bifurcation Aneurysm. World Neurosurg. 2018 Dec 31. pii: S1878-8750(18)32916-4.
doi: 10.1016/j.wneu.2018.12.093. [Epub ahead of print] PubMed PMID: 30605760.
)).
----
Direct operative management of [[basilar bifurcation aneurysm]]s is one of the most challenging procedures in the realm of vascular neurosurgery, as these lesions are deeply situated in the [[interpeduncular]] region and maintain an intimate relationship with important anatomical structures. Direct clipping of aneurysms generally represents the gold standard of surgical treatment, as it allows exclusion of the aneurysmal sac from the circulation, evacuation of aneurysmal contents for decompression, and preservation of efferent flow. 

===== Timing =====

Initial experience tended to favor allowing [[basilar tip aneurysm]]s to “cool-down” for ≈ 10–14 days after SAH before attempting surgery to permit [[cerebral edema]] to subside. More recently, early surgery for these aneurysms has been advocated as for [[anterior circulation aneurysm]]s
((Peerless SJ, Hernesniemi JA, Gutman FB, Drake CG. Early Surgery for Ruptured Vertebrobasilar Aneurysms. JNeurosurg. 1994; 80:643–649)).

However, some surgeons still recommend waiting ≈ 1 week
((Chyatte D, Philips M. Surgical Approaches for Basilar Artery Aneurysms. Contemp Neurosurg. 1991; 13:1–6))
, and most would agree that if there are obvious technical difficulties because of [[aneurysm size]], configuration or location of the aneurysm, that early surgery may not be appropriate. Also, if during the craniotomy it becomes apparent that cerebral edema is impairing the exposure, the operation should be aborted and attempted again at a later date.

===== Approaches =====

see [[Basilar bifurcation aneurysm approaches]].


===== Large broad-based basilar apex aneurysm =====

Large, broad-based [[basilar apex aneurysm]]s involving multiple arterial origins are complex lesions commonly not amenable to direct clipping or endovascular management.

BA proximal (Hunterian) occlusion with extracranial-to-intracranial bypass is a supported strategy if one or both posterior communicating arteries are small. [[Hunterian ligation]] risks sudden aneurysm thrombosis and thromboembolism in the perforator rich BA apex. There currently exists no guidelines for [[antiplatelet]] and [[anticoagulant]] therapy following Hunterian ligation for complex BA apex aneurysm treatment. 

Ravina et al presented in 2018 a literature review and an illustrative case of an 18-year-old man who presented with progressive [[headache]]s and was found to have a large, unruptured BA apex aneurysm involving the origins of bilateral superior cerebellar and posterior cerebral arteries. Given the small posterior communicating arteries and complexity of the aneurysm, proximal BA occlusion with unilateral superficial temporal artery-to-superior cerebellar artery bypass was recommended. Despite antiplatelet treatment with [[acetylsalicylic acid]] pre- and postoperatively, the patient developed acute [[ischemia]] of the [[brainstem]] and [[cerebellum]] as well as an embolic left [[temporal lobe]] [[infarct]]. The patient received [[dual antiplatelet therapy]] starting postoperative day 6 following which he experienced no new infarcts and made a significant neurologic recovery. The current evidence suggests that proximal BA occlusion in complex BA apex aneurysm cases is thrombogenic and can be especially dangerous if thrombosis occurs suddenly in aneurysms without pre-existing intraluminal thrombus. Dual antiplatelet therapy during the first postoperative week presents a possible strategy for reducing the risk of ischemia due to sudden aneurysm thrombosis
((Ravina K, Strickland BA, Buchanan IA, Rennert RC, Kim PE, Fredrickson VL,
Russin JJ. Postoperative antiplatelet therapy in the treatment of complex basilar
apex aneurysms implementing Hunterian ligation and extracranial-to-intracranial
bypass: review of the literature with an illustrative case report. World
Neurosurg. 2018 Dec 8. pii: S1878-8750(18)32798-0. doi:
10.1016/j.wneu.2018.11.237. [Epub ahead of print] Review. PubMed PMID: 30537547.
)).

===== References =====