Introduction
Endovascular procedures are used for treating traumatic pseudoaneurysms of the internal carotid artery (ICA). Although endovascular occlusion using metallic coils or detachable balloons with preservation of the parent artery has been attempted,10) this technique should be avoided for treating pseudoaneurysms due to the fragile nature of the aneurysm wall, which may not support the embolic device. Growth of the aneurysm and potentially fatal bleeding can result when the embolic device is not supported.4)11) Another treatment method for ICA pseudoaneurysms is endovascular trapping, which is technically easy, and it has several advantages over the parent artery salvage technique.7)9) Endovascular trapping also has a low risk of complications.3)7)9)
The present report describes two cases in which endovascular balloon placement resulted in incomplete occlusion of an ICA pseudoaneurysm due to an unobserved anastomosis. Subsequent surgical clipping resulted in successful occlusion. We also discuss the technical issues related to our procedure.
Description of Cases
CASE 1
A 49-year-old woman was admitted to our department due to repeated epistaxis, orbital bruits and headache. She was involved in a motor vehicle accident six months before the present admission. No sign existed of cranial nerve dysfunction. Digital subtraction angiography (DSA) of her right ICA demonstrated a carotid-cavernous fistula (CCF) with pseudoaneurysm in the sphenoid sinus (Fig 1, A). Selective external carotid angiography showed no filling of the aneurysm through the external carotid artery (ECA) collaterals. Gold-valve detachable balloons (Nycomed Ingenor, France) were introduced into the CCF while preserving the lumen of the right ICA. The DSA revealed complete resolution of the CCF (Fig 1, B). Yet two weeks after balloon embolization, the patient experienced massive epistaxis. DSA revealed an irregular pseudoaneurysm of the right cavernous ICA, and this demonstrated that the previous balloon occlusion of the fistula site failed to preserve the ICA. In response, we planned to trap the involved site of the ICA. Before permanent occlusion of the ICA, balloon test occlusion was performed together with single photon-emission computed tomography in order to confirm adequate collateral blood flow and subclinical hypoperfusion.6)12) During the balloon test occlusion, careful neurologic examination was performed, including motor and sensory testing and assessment of her speech and memory. The patient well tolerated the balloon test occlusion and there was no evidence of focal neurologic changes. With the patient under systemic heparinization, the ICA was then occluded using three detachable balloons. The first balloon was detached at the level of the aneurysm opening in order to occlude the aneurysm and the parent artery. The second balloon was placed just proximal to the first balloon, thereby functioning as a safeguard to ensure complete occlusion of the ICA. The third balloon was detached at the proximal ICA to obliterate the blind arterial lumen, which can be a thrombogenic focus.9) The DSA before balloon detachment seemed to demonstrate good collateral circulation to the right ICA territory and no aneurysmal filling from the collateral circulation; however, after occlusion of the ICA, the aneurysm was slightly filled due to the presence of an external carotid-ophthalmic anastomosis (Fig 1, C). The patient, who well tolerated the procedure without evidence of focal neurologic changes, was kept well-hydrated and we closely monitored her. Antiplatelet agents were also given, and she was discharged without any neurologic deficits. Yet four months later, she was admitted again to our emergency department due to recurrent epistaxis. Subsequent DSA showed prominent retrograde filling of both the distal segment of the injured ICA and the aneurysm via ophthalmic collaterals, which had been negligible on the images obtained by performing external carotid angiography four months previously (Fig 1, D). A retrospective review of the DSA revealed that the aneurysm (while still small) was becoming larger. Therefore, application of a surgical clip was planned through the external carotid-ophthalmic anastomosis to prevent rebleeding of the pseudoaneurysm. After the standard pterional craniotomy and resection of the anterior clinoid process, we applied a surgical clip to the ICA just proximal to the origin of the ophthalmic artery (Fig 1, E). The follow-up vertebral angiography showed complete occlusion of the pseudoaneurysm (Fig 1, F).

CASE 2
A 21-year-old male patient presented with massive epistaxis and blindness in his right eye. He had fallen two months prior to his appearance at our emergency department. Computed tomography of the head revealed multiple frontal skull-base fractures, a small epidural hematoma and encephalomalacic changes in the cerebral hemispheres. Magnetic resonance imaging (MRI) showed a large, organized hematoma filling the sphenoid sinus and nasal cavity (Fig 2, A). Those clinical and imaging findings led us to conclude that the epistaxis was due to a traumatic pseudoaneurysm in the cavernous segment of the ICA.
DSA revealed an irregular-shaped pseudoaneurysm in the cavernous ICA; the right ophthalmic artery was not visualized on internal carotid angiography (Fig 2, B). Compression of the right ICA demonstrated good collateral circulation from the left ICA via the anterior communicating artery, and the Alcock test showed retrograde early visualization of the aneurysm and ophthalmic artery via the posterior communicating artery (Fig 2, C). External carotid angiography showed no filling into the aneurysm (Fig 2, D). With the patient under systemic heparinization, the ICA was occluded using three detachable balloons.
DSA after balloon detachment demonstrated good collateral circulation to the right ICA territory, with no aneurysmal filling from the posterior circulation. However, the aneurysm was visualized at a more delayed phase according to the external carotid angiography that was performed after the procedure (Fig 2, E). Follow-up DSA performed one week later showed that the ballooning state was well-maintained, but follow-up DSA also showed filling of the aneurysm through the external carotid-ophthalmic anastomosis (Fig 2, F). In this case, applying a surgical clip was planned to prevent rebleeding of the pseudoaneurysm through the external carotid-ophthalmic anastomosis. After the standard pterional craniotomy and resection of the anterior clinoid process, we applied a surgical clip to the ICA just proximal to the origin of the ophthalmic artery. Postoperative follow-up angiography showed complete occlusion of the pseudoaneurysm (Fig 2, G). The MRI performed four months after the operation demonstrated that both the organized hematoma and the pseudoaneurysm in the sphenoid sinus and nasal cavity had resolved.
Discussion
Although traumatic pseudoaneurysm of the internal carotid artery (ICA) is a very rare cause of epistaxis, it is a life-threatening clinical situation if it is left untreated.2)5)8)9) Therapeutic occlusion of the ICA using endovascular methods can be easily accomplished and these methods have a low risk of complications.3)7)9) These techniques can be performed under local anesthesia while the patient’s neurologic status is being continuously monitored. A complete and permanent exclusion of an aneurysm from the arterial circulation can be achieved by occlusion of the aneurysm opening or trapping of the parent artery with detachable balloons or coils. A test occlusion can be easily performed so as to ensure tolerance (that is, that the patient has no adverse neurologic or other effects) prior to therapeutic occlusion.7)
However incomplete occlusion and even of a very small aneurysm can result in eventual regrowth of an aneurysm, and this has the potential to be fatal (the woman in case 1 was at risk for fatality due to lesion regrowth). We planned performing short-term follow-up angiography to detect sudden regrowth of the pseudoaneurysm in the second case. As expected, the follow-up angiography performed one week after the initial operation showed that the aneurysm had become larger. So, we decided to immediately intervene since accelerated aneurysmal filling through the external carotid-ophthalmic anastomosis has the same risk of rupture as an untreated pseudoaneurysm.1)
In the current cases, we think that the incomplete occlusion was due to the fact that the external carotid-ophthalmic artery anastomosis was not detected before detaching the balloons. However, other technical reasons can also result in incomplete treatment. Correct placement of the microcatheter, for deploying a coil or balloon in the ICA distal to the aneurysm, can be difficult due to strong blood flow inside a large aneurysm and due to the complex and ill-defined anatomy of a severely injured ICA near the pseudoaneurysm. Failure to select the distal ICA with a microcatheter or incorrect microcatheter placement can also lead to incomplete occlusion of the aneurysm.
For incompletely treated cases, additional coil or balloon embolization of the distal stump is impossible via the same route due to the previously placed balloons. An alternative pathway, via the contralateral ICA and anterior communicating artery or via the vertebral artery and the posterior communicating artery, should also be considered. However, if the communicating artery is injured during the procedure, then there is the risk of contralateral hemisphere infarction and a catastrophic outcome.13) Occlusion of the anastomosis site (the ophthalmic artery of the ICA and the middle meningeal artery of the ECA) is complicated because the exact location of the anastomosis can be difficult to find. Therefore, we performed surgery to apply clips to the ICA just proximal to the origin of the ophthalmic artery since ligation at that point was possible without difficulty.
Conclusion
Treatment that results in only incomplete occlusion of a pseudoaneurysm leaves the patient with the same risk profile as does not treating the aneurysm. Therefore, it is critical to confirm the blood flow through the external carotid or posterior circulation prior to the final positioning of the balloons or coils. Finally, when collateral blood flow is observed, immediate additional treatment should be performed in order to prevent fatal rupture of the pseudoaneurysm.
REFERENCES
1)Araki C, Handa H, Handa J, Yoshida K. Traumatic aneurysm of the intracranial extradural portion of the internal carotid artery. Report of a case. J Neurosurg 23:64-7, 1965
2)Chambers EF, Rosenbaum AE, Norman D, Newton TH. Traumatic aneurysms of cavernous internal carotid artery with secondary epistaxis. AJNR Am J Neuroradiol 2:405-9, 1981
3)Chen D, Concus AP, Halbach VV, Cheung SW. Epistaxis originating from traumatic pseudoaneurysm of the internal carotid artery: diagnosis and endovascular therapy. Laryngoscope 108:326-31, 1998
4)Crow WN, Scott BA, Guinto FC Jr., Chaljub G, Wright G, Rabassa AE et al. Massive epistaxis due to pseudoaneurysm. Treated with detachable balloons. Arch Otolaryngol Head Neck Surg 118:321-4, 1992
5)Ding MX. Traumatic aneurysm of the intracavernous part of the internal carotid artery presenting with epistaxis. Case report. Surg Neurol 30:65-7, 1988
6)Ferguson GG, Drake CG. Carotid-ophthalmic aneurysms: the surgical management of those cases presenting with compression of the optic nerves and chiasm alone. Clin Neurosurg 27:263-307, 1980
7)Fox AJ, Vinuela F, Pelz DM, Peerless SJ, Ferguson GG, Drake CG et al. Use of detachable balloons for proximal artery occlusion in the treatment of unclippable cerebral aneurysms. J Neurosurg 66:40-6, 1987
8)Goleas J, Mikhael MA, Paige ML, Wolff AP. Intracavernous carotid artery aneurysm presenting as recurrent epistaxis. Ann Otol Rhinol Laryngol 100:577-9, 1991
9)Han MH, Sung MW, Chang KH, Min YG, Han DH, Han MC. Traumatic pseudoaneurysm of the intracavernous ICA presenting with massive epistaxis: imaging diagnosis and endovascular treatment. Laryngoscope 104:370-7, 1994
10)Higashida RT, Halbach VV, Dowd CF, Barnwell SL, Hieshima GB. Intracranial aneurysms: interventional neurovascular treatment with detachable balloons--results in 215 cases. Radiology 178:663-70, 1991
11)Lee DH, Hur SH, Choi SJ, Jung SM, Ryu DS, Park MS et al. A recurred carotid siphon pseudoaneurysm after detachable coil embolization. Successful endovascular management with detachable balloons. Interv Neuroradiol. 8:61-5, 2002
12)Matsuda H, Higashi S, Asli IN, Eftekhari M, Esmaili J, Seki H et al. Evaluation of cerebral collateral circulation by technetium-99m HM-PAO brain SPECT during Matas test: report of three cases. J Nucl Med 29:1724-9, 1988
13)Wilms G, Demaerel P, Lagae L, Casteels I, Mombaerts I. Direct caroticocavernous fistula and traumatic dissection of the ipsilateral internal carotid artery: endovascular treatment. Neuroradiology 42:62-5, 2000