Update: Giant internal carotid artery aneurysm

Sixty percent of giant intracranial aneurysms occur on the internal carotid artery.


Parent artery occlusion was the classic therapy; now the stent-assisted coil embolization has become available in recent years, but the optimal therapy is under debate.

Stent-assisted coiling may not be superior to parent artery occlusion in selected patients after short-term follow-up. Parent artery occlusion is a simple, safe and effective treatment for large/giant internal carotid aneurysms 1).

ICA occlusion for large and giant aneurysms after angiographic test occlusion was safe and effective. Two-thirds of eligible patients passed the angiographic test. Most aneurysms shrunk, and most cranial nerve dysfunctions were cured or improved 2).

Case series


Between January 1995 and January 2015, occlusion of the ICA was considered in 146 patients with large or giant ICA aneurysms. Ninety-six patients (66%) passed the angiographic test occlusion, and, in 88 of these 96 patients (92%), the ICA was permanently occluded. In 11 of 88 patients with angiographic tolerance, ICA occlusion was performed with the patient under general anesthesia without clinical testing.

There was 1 hypoperfusion infarction after hypovolemic shock from a large retroperitoneal hematoma (complication rate 1.1% [95% CI, 1%-6.8%]). The mean imaging and clinical follow-up was 35 months (median 18 months; range, 3-180 months). On the latest MR imaging, 87 of 88 aneurysms (99%) were completely occluded and 61 of 80 aneurysms (76%) were decreased in size or completely obliterated. Of 62 patients who presented with cranial nerve dysfunction by mass effect of the aneurysm, 30 (48%) were cured, 25 (40%) improved, 6 (10%) were unchanged, and 1 patient (2%) was hemiplegic after a complication.

ICA occlusion for large and giant aneurysms after angiographic test occlusion was safe and effective. Two-thirds of eligible patients passed the angiographic test. Most aneurysms shrunk, and most cranial nerve dysfunctions were cured or improved 3).

In the report of Li et al. all the patients were divided into two groups: Group A: patients who underwent parent artery occlusion, and Group B: patients who underwent stent-assisted coil embolization. Follow-up outcomes were evaluated using the modified Rankin Scale (mRS).

After 12 months of follow-up, the favorable outcome (mRS: 0-2) had no statistical significance in both groups (p = 1.00). Patients in group A had greater ischemia compared with patients in group B, but the difference did not reach statistical significance (p = 0.421). In group B, patients had a higher rate of partial occlusion (p = 0.255) and recurrence (10% vs. 0%; p = 0.586).

Stent-assisted coiling may not be superior to parent artery occlusion in selected patients after short-term follow-up. Parent artery occlusion is a simple, safe and effective treatment for large/giant internal carotid aneurysms.


Four cases of giant or large paraclinoid aneurysms of the internal carotid artery successfully trapped after assessing blood flow using a flowmeter are presented. In all cases, the initial plan for clipping was changed to aneurysm trapping due to various reasons. The collateral blood flow was assessed using the flowmetry test, the original procedure of measuring volumetric blood flow in the middle cerebral artery using an ultrasonic flowmeter. We analyze the reasons for clipping refusal, the procedure of measuring blood flow, treatment outcomes, and catamnestic data. The risks of reconstructive surgeries involving the internal carotid artery are discussed and the literature data are analyzed. Conclusions. Ultrasonic flowmetry is a simple and safe method for intraoperative control over blood circulation, which may play the key role in complicated surgical cases 4).


Rathore et al. retrospectively analyzed 27 patients with giant and complex ICA aneurysms who underwent carotid artery ligation between January 2001 and December 2010. Clinical presentation included headache, vision loss and diplopia. There were 19 patients with cavernous aneurysm, 5 supraclinoid, 1 ophthalmic, 1 petrous segment and 1 cervical segment aneurysm located extracranially. All demonstrated good cross-circulation. Selverstone clamp was used for gradual occlusion of the ICA over 72 h under closed observation in the intensive care unit.

Six patients developed hemiparesis in the postoperative period. Improvement occurred in one patient over two to three weeks while the remaining five patients had residual hemiparesis. One patient developed malignant MCA infarct for which decompressive craniectomy had to be done. There was no mortality in the present series.

Gradual monitored occlusion and ICA ligation may be a simple, safe alternative procedure to clipping in surgically inaccessible and complex aneurysms, especially for surgeons with limited experience. Cross circulation study is an absolute requisite for carotid ligation 5).


In 16 patients with 17 large or giant (11-45 mm) unruptured ICA aneurysms presenting with dysfunction of cranial nerves (CN) II, III, IV, or VI, selective coil occlusion was performed. From a cohort of 39 patients with ICA aneurysms treated with ICA occlusion and long-term follow-up, we selected 31 patients with aneurysms presenting with cranial nerve dysfunction. Clinical recovery at follow-up from oculomotor dysfunction and visual symptoms was compared for both treatment modalities.

Of 17 aneurysms treated with selective coiling, symptoms of cranial nerve dysfunction resolved in 3, improved in 10, and remained unchanged in 4. In 9 of 17 patients, additional coiling during follow-up was required. Of 31 aneurysms treated with carotid artery occlusion, cranial nerve dysfunction resolved in 19, improved in 9, and remained unchanged in 3. These differences were not significant. There were no complications of treatment.

Recovery of ICA aneurysm-induced cranial nerve dysfunction occurs in most patients, both after ICA occlusion and after selective coiling. In patients who cannot tolerate ICA occlusion, selective aneurysmal occlusion with coils is a valuable alternative 6).

Case reports


Bowers et al. report the microsurgical rescue and removal of a Pipeline stent embolization of a giant internal carotid artery terminus aneurysm. After the initial placement of a Pipeline Embolization Device (PED), it migrated proximally to the cavernous carotid with the distal end free in the middle of the aneurysm, resulting in only partial aneurysm neck coverage. The patient underwent microsurgical rescue with trapping, bypass, and opening of the aneurysm with PED removal. The vessel remained patent in the proximal segment previously covered by the Pipeline stent. Microsurgical rescue for definitive aneurysm treatment with PED removal can be safe and effective for aneurysms unsuccessfully treated with PED 7).


A 25-year-old man developed Wallenberg syndrome (WS). At that time his carotid angiography was normal. When he was 28 years old, he suffered from retinal artery embolism in the left eye. At the age of 30 years, he had an acute onset of abducens nerve palsy in his right eye. The carotid angiography showed a giant aneurysm at the cavernous sinus portion in the right internal carotid artery. At his age of 38, the right oculomotor, trochlear and trigeminal nerves were involved. A vertebral angiography revealed a bead-like formation, and a diagnosis of fibromuscular dysplasia (FMD) was made. An intensive angiographic examination revealed many stenotic or dilated lesions in the carotid, vertebral, coronary, renal, and hepatic arteries. A sural nerve biopsy specimen revealed that the sural vein was involved. In Japan only one case of FMD presenting with WS is known. FMD should be under consideration as an underlying disease, when WS occurred in younger patients with few risk factors. In this patient an angiography revealed no abnormality in the cavernous sinus portion of the internal carotid artery, when he suffered from WS. However, eight years later he was proved to have a giant aneurysm in the cavernous sinus portion. In conclusion, we support the hypothesis that aneurysm may originate from angiographically normal arterial wall in FMD 8).

1) Li H, He XY, Li XF, Zhang X, Liu YC, Duan CZ. Treatment of giant/large internal carotid aneurysms: parent artery occlusion or stent-assisted coiling. Int J Neurosci. 2016 Jan;126(1):46-52. doi: 10.3109/00207454.2014.992427. Epub 2015 Jan 7. PubMed PMID: 25565057.
2) , 3) Bechan RS, Majoie CB, Sprengers ME, Peluso JP, Sluzewski M, van Rooij WJ. Therapeutic Internal Carotid Artery Occlusion for Large and Giant Aneurysms: A Single Center Cohort of 146 Patients. AJNR Am J Neuroradiol. 2016 Jan;37(1):125-9. doi: 10.3174/ajnr.A4487. Epub 2015 Aug 20. PubMed PMID: 26294643.
4) Shekhtman OD, Eliava ShSh, Pilipenko YI. [Trapping of large and giant paraclinoid aneurysm based on intraoperative flowmetry test]. Zh Vopr Neirokhir Im N N Burdenko. 2014;78(5):16-22; discussion 22. Russian. PubMed PMID: 25406904.
5) Rathore YS, Chandra PS, Kumar R, Singh M, Sharma MS, Suri A, Mishra NK, Gaikwad S, Garg A, Sharma BS, Mahapatra AK. Monitored gradual occlusion of the internal carotid artery followed by ligation for giant internal carotid artery aneurysms. Neurol India. 2012 Mar-Apr;60(2):174-9. doi: 10.4103/0028-3886.96396. PubMed PMID: 22626699.
6) van Rooij WJ, Sluzewski M. Unruptured large and giant carotid artery aneurysms presenting with cranial nerve palsy: comparison of clinical recovery after selective aneurysm coiling and therapeutic carotid artery occlusion. AJNR Am J Neuroradiol. 2008 May;29(5):997-1002. doi: 10.3174/ajnr.A1023. Epub 2008 Feb 22. PubMed PMID: 18296545.
7) Bowers CA, Taussky P, Park MS, Neil JA, Couldwell WT. Rescue microsurgery with bypass and stent removal following Pipeline treatment of a giant internal carotid artery terminus aneurysm. Acta Neurochir (Wien). 2015 Dec;157(12):2071-5. doi: 10.1007/s00701-015-2593-3. Epub 2015 Oct 2. PubMed PMID: 26429702.
8) Nishiyama K, Fuse S, Shimizu J, Takeda K, Sakuta M. [A case of fibromuscular dysplasia presenting with Wallenberg syndrome, and developing a giant aneurysm of the internal carotid artery in the cavernous sinus]. Rinsho Shinkeigaku. 1992 Oct;32(10):1117-20. Japanese. PubMed PMID: 1297556.

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