Junctional Internal Carotid Artery Aneurysms: The Schrödinger's Cat of Vascular Neurosurgery

Abstract

Objectives Despite advances in neuroimaging, it is not always definitive whether a paraclinoid aneurysm is intradural or entirely extradural. We illustrate the potential use of surgical exploration in these aneurysms that we refer to as “junctional” aneurysms.

Methods Retrospective review of eight patients with unruptured aneurysms who underwent a planned surgical exploration of a junctional aneurysm.

Results Of the eight patients, three underwent exploration of the aneurysm during surgery for a different aneurysm. All three of these were found to be extradural. Five patients underwent a craniotomy for the exclusive purpose of clarifying the location of the aneurysm. Two of these cases were found to be intradural and were clipped. Two cases were found to be extradural. In one patient, the initially extradural aneurysm was converted into an intradural aneurysm during removal of the anterior clinoid process, necessitating surgical clipping. One transient third nerve palsy was observed.

Discussion Until further progress in neuroimaging allows clinicians to determine unequivocally the exact anatomical location of a paraclinoid aneurysm, we advocate the use of the term junctional aneurysm to reflect the clinical uncertainty inherent in management decisions made regarding these aneurysms. We have illustrated a strategy of surgical exploration in select patients.

Keywords

cerebral aneurysm - paraclinoid - internal carotid artery - distal dural ring - carotid cave - ophthalmic

• References

• 1 Wiebers DO. Unruptured intracranial aneurysms: natural history and clinical management. Update on the international study of unruptured intracranial aneurysms. Neuroimaging Clin N Am 2006; 16 (3) 383-390 , vii
• 2 Thines L, Lee SK, Dehdashti AR , et al. Direct imaging of the distal dural ring and paraclinoid internal carotid artery aneurysms with high-resolution T2 turbo-spin echo technique at 3-T magnetic resonance imaging. Neurosurgery 2009; 64 (6) 1059-1064 ; discussion 1064
• 3 Thines L, Gauvrit JY, Leclerc X , et al. Usefulness of MR imaging for the assessment of nonophthalmic paraclinoid aneurysms. AJNR Am J Neuroradiol 2008; 29 (1) 125-129
• 4 Thines L, Delmaire C, Le Gars D , et al. MRI location of the distal dural ring plane: anatomoradiological study and application to paraclinoid carotid artery aneurysms. Eur Radiol 2006; 16 (2) 479-488
• 5 Gonzalez LF, Walker MT, Zabramski JM, Partovi S, Wallace RC, Spetzler RF. Distinction between paraclinoid and cavernous sinus aneurysms with computed tomographic angiography. Neurosurgery 2003; 52 (5) 1131-1137 ; discussion 1138–1139
• 6 Hashimoto K, Nozaki K, Hashimoto N. Optic strut as a radiographic landmark in evaluating neck location of a paraclinoid aneurysm. Neurosurgery 2006; 59 (4) 880-895 ; discussion 896–897
• 7 Tsuboi T, Tokunaga K, Shingo T , et al. Differentiation between intradural and extradural locations of juxta-dural ring aneurysms by using contrast-enhanced 3-dimensional time-of-flight magnetic resonance angiography. Surg Neurol 2007; 67 (4) 381-387
• 8 Hirai T, Kai Y, Morioka M , et al. Differentiation between paraclinoid and cavernous sinus aneurysms with contrast-enhanced 3D constructive interference in steady- state MR imaging. AJNR Am J Neuroradiol 2008; 29 (1) 130-133
• 9 Watanabe Y, Makidono A, Nakamura M, Saida Y. 3D MR cisternography to identify distal dural rings: comparison of 3D-CISS and 3D-SPACE sequences. Magn Reson Med Sci 2011; 10 (1) 29-32
• 10 Watanabe Y, Nakazawa T, Yamada N , et al. Identification of the distal dural ring with use of fusion images with 3D-MR cisternography and MR angiography: application to paraclinoid aneurysms. AJNR Am J Neuroradiol 2009; 30 (4) 845-850
• 11 Bouthillier A, van Loveren HR, Keller JT. Segments of the internal carotid artery: a new classification. Neurosurgery 1996; 38 (3) 425-432 ; discussion 432–433
• 12 Kobayashi S, Kyoshima K, Gibo H, Hegde SA, Takemae T, Sugita K. Carotid cave aneurysms of the internal carotid artery. J Neurosurg 1989; 70 (2) 216-221
• 13 Punt J. Some observations on aneurysms of the proximal internal carotid artery. J Neurosurg 1979; 51 (2) 151-154
• 14 Taptas JN. Intradural and extradural ICA. J Neurosurg 1979; 51 (6) 877-878
• 15 Oikawa S, Kyoshima K, Kobayashi S. Surgical anatomy of the juxta-dural ring area. J Neurosurg 1998; 89 (2) 250-254
• 16 Beretta F, Sepahi AN, Zuccarello M, Tomsick TA, Keller JT. Radiographic imaging of the distal dural ring for determining the intradural or extradural location of aneurysms. Skull Base 2005; 15 (4) 253-261 ; discussion 261–262
• 17 Murayama Y, Sakurama K, Satoh K, Nagahiro S. Identification of the carotid artery dural ring by using three-dimensional computerized tomography angiography. Technical note. J Neurosurg 2001; 95 (3) 533-536
• 18 Ito K, Hongo K, Kakizawa Y, Kobayashi S. Three-dimensional contrast medium-enhanced computed tomographic cisternography for preoperative evaluation of surgical anatomy of intradural paraclinoid aneurysms of the internal carotid artery: technical note. Neurosurgery 2002; 51 (4) 1089-1092 ; discussion 1092–1093
• 19 Barami K, Hernandez VS, Diaz FG, Guthikonda M. Paraclinoid carotid aneurysms: surgical management, complications, and outcome based on a new classification scheme. Skull Base 2003; 13 (1) 31-41
• 20 Chalouhi N, Starke RM, Yang S , et al. Extending the indications of flow diversion to small, unruptured, saccular aneurysms of the anterior circulation. Stroke 2014; 45 (1) 54-58
• 21 Juvela S, Porras M, Poussa K. Natural history of unruptured intracranial aneurysms: probability of and risk factors for aneurysm rupture. J Neurosurg 2008; 108 (5) 1052-1060