Perspectives Commentary on: Evolution of Management Strategies for Cavernous Carotid Aneurysms: A Review by Ambekar et al. pp. 1077-1085.

H. Hunt Batjer, M.D. Professor and Chair Department of Neurological Surgery The University of Texas Southwestern

Cavernous Carotid Aneurysms: You Can But Should You? Babu G. Welch1,2 and H. Hunt Batjer1

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neurysms of the cavernous carotid segment (i.e., cavernous carotid aneurysm [CCA]) have long been understood to have an overall low risk of rupture and otherwise low risk of life-altering complications. During the past few decades, the use of noninvasive imaging studies for various neurologic complaints has resulted in the increased detection of CCAs. Cerebrovascular specialists are now asked routinely to provide a treatment recommendation to patients with unruptured and otherwise-asymptomatic CCAs. Despite the relatively benign natural history of these lesions, a proliferation of management choices has increased the likelihood that asymptomatic aneurysms will undergo treatment.

The authors provide an excellent review of the historical and current literature as it relates to aneurysms of the cavernous sinus. In this review, they emphasize the fact that presentation of the lesions is more likely to be related to mass effect (cranial neuropathy, headache) or embolic complications rather than hemorrhage. They appropriately emphasize that the etiology of the aneurysm should be considered when contemplating the natural history and risk to the patient. Simply put, a cavernous aneurysm related to iatrogenic or accidental trauma has an aggressive natural history and should be managed accordingly. The concept of the transitional aneurysm always should be mentioned with the cavernous aneurysm. Although rupture of CCAs is rare, the authors suggest a cumulative 5-year risk of 6.4% for those lesions >25 mm in size. As the creation of a cavernous-carotid fistula from the rupture of a cavernous lesion is quite rare in our own experience, it is more likely that those larger lesions have entered the subarachnoid space to produce the hemorrhage. Although the identification of an aneurysm “waist”

Key words Carotid aneurysm - Cavernous aneurysm - Coiling - ICA aneurysm - Stenting -

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Abbreviations and Acronyms CCA: Cavernous carotid aneurysm

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on angiography has suggested a subarachnoid component to the cavernous aneurysm, advancements in high-resolution magnetic resonance imaging have the potential to better describe this relationship (1). Each center should have an imaging protocol established for the evaluation of these lesions because of their unique site at the cranial base. Historically, the treatment options for the CCA included conservative nonsurgical management and surgical strategies to include Hunterian ligation with or without bypass revascularization. Management by observation alone can have mixed results in symptomatic patients, especially in patients with retro-orbital and facial pain. In some cases, antiplatelet therapy may be initiated; especially in light of transient ischemic attack. The response to such therapy in patients with cranial neuropathy is random. In partial thrombosed lesions, the likelihood of recanalization should be anticipated and imaging follow-up should be the routine. During the last decade, endovascular techniques have nearly supplanted surgical strategies through the use of coils, vascular reconstruction, and flow-diverting devices. Despite the increase of endovascular techniques, the adequacy of intracranial collateral circulation remains a point of consideration in the preoperative evaluation. Particularly useful in this publication is the discussion of the various methods for evaluation of that collateral circulation should the option of carotid sacrifice be considered. Although xenon-enhanced computed tomography and singleproton emission computed tomography imaging provide useful information, the ideal testing of collateral circulation should be in the angiography suite during the balloon occlusion test. The steady improvements in biplane fluoroscopy make it likely that perfusion imaging will be coupled with the digital analysis of

From the Departments of 1Neurological Surgery and 2Radiology, The University of Texas Southwestern, Dallas, Texas, USA To whom correspondence should be addressed: H. Hunt Batjer, M.D. [E-mail: [email protected]] Citation: World Neurosurg. (2014) 82, 6:996-997. http://dx.doi.org/10.1016/j.wneu.2014.06.029

WORLD NEUROSURGERY, http://dx.doi.org/10.1016/j.wneu.2014.06.029

PERSPECTIVES

contrast transit times to provide a more accurate understanding of perfusion symmetry in the near future. It is much easier to troubleshoot an endovascular complication when there is a good understanding of the collateral circulation. With the litany of choices available and the continued mystery of the actual natural history of cavernous carotid lesions, decisions often are made on a very individual basis without overwhelming evidence to support any one strategy. On the basis of the preprocedural evaluation, a reconstructive or deconstructive treatment strategy may be adopted. Reconstructive strategies include direct microsurgical clip application, coil embolization with or without the use of a vascular reconstruction device, flow-diverting devices, or the use of liquid embolic agents. Although endovascular techniques dominate the available options for the treatment of CCAs, the combination of microsurgery and endovascular techniques should be considered as treatment possibilities. This is particularly important where contraindications exist to purely endovascular therapies (e.g., bleeding diathesis, antiplatelet resistance, tortuous proximal anatomy). When used, a combined strategy also should be based on the capabilities of the treating facility. As an adjunct to surgery, endovascular techniques may be applied for proximal vessel control, vessel sacrifice, as well a surgical salvage. Balloon occlusion may be used for proximal control in lieu of surgical exposure of the cervical carotid artery. When performed with a large lumen catheter, the same exposure may be used to provide suction decompression. This technique is useful to reduce the volume of the aneurysm and improve visualization for primary clip reconstruction. Fulkerson et al. (1) reported a comparative experience of ophthalmic aneurysms managed with and without this endovascular adjunct in 2009. Endovascular suction decompression provided variable benefit that was primarily related to the presence of calcification within the aneurysm wall. Most importantly, the use of an endovascular adjunct did not increase the procedural morbidity

REFERENCES 1. Fulkerson DH, Horner TG, Payner TD, Leipzig TJ, Scott JA, Denardo AJ, Redelman K, Goodman JM: Endovascular retrograde suction decompression as an adjunct to surgical treatment of ophthalmic aneurysms: analysis of risks and clinical outcomes. Neurosurgery 64(3 Suppl):ons107-ons111, 2009: discussion ons111-112.

(2). The necessity of occluding the ophthalmic artery during suction decompression cannot be overstated. The surgical addition to endovascular therapy comes primarily from flow augmentation, or bypass, in the case of vessel sacrifice. Surgery may also provide a more precise distal vessel occlusion (proximal to the ophthalmic artery) in same setting. In cases of tortuous proximal anatomy, surgical cut down and/or direct catheterization of the internal carotid artery may allow the passage of microcatheters to use the desired endovascular strategy. Despite our suggestion that definitive or adjunctive surgical therapies be considered, we are favorably disposed to the use of flow-diversion in the treatment of CCAs. As we address the continued issues with access and device deployment, the treatment of what is truly a segmental disease will likely be more responsive to a constructive therapy rather than a deconstructive one. With that favorable perspective, however, comes a realization that the progressive thrombosis promoted by flow diversion may exacerbate the cranial nerve pathology that routinely is encountered in symptomatic CCAs. Our own experience suggests that symptoms of optic nerve compression are the least likely to resolve. The likelihood of postprocedure headaches is underappreciated and should also be a point of discussion with the patient preoperatively. Aneurysms of the cavernous internal carotid artery can present in a variety of clinical situations. The severity and duration of the clinical complaints as well as the anatomy of the aneurysm typically govern the management of these lesions. Although endovascular strategies dominate current treatment preferences, it is necessary to understand the microsurgical adjuncts that may provide a more durable treatment. Despite a low risk of rupture, cavernous aneurysms will increase in prevalence and present a treatment dilemma. The current generation of comprehensive cerebrovascular surgeons will have the ability to provide complex care to the most complex vascular lesions of the skull base. As we learn many times, however, the question to answer is not “could you?” but “should you?”

2. Hirai T, Kai Y, Morioka M, Yano S, Kitajima M, Fukuoka H, Sasao A, Murakami R, Nakayama Y, Awai K, Toya R, Akter M, Korogi Y, Kuratsu J, Yamashita Y: Differentiation between paraclinoid and cavernous sinus aneurysms with contrastenhanced 3D constructive interference in steadystate MR imaging. Am J Neuroradiol 29:130-133, 2008.

WORLD NEUROSURGERY 82 [6]: 996-997, DECEMBER 2014

Citation: World Neurosurg. (2014) 82, 6:996-997. http://dx.doi.org/10.1016/j.wneu.2014.06.029 Journal homepage: www.WORLDNEUROSURGERY.org Available online: www.sciencedirect.com 1878-8750/$ - see front matter ª 2014 Elsevier Inc. All rights reserved.

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Cavernous carotid aneurysms: you can but should you?

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