Anterior paraclinoid aneurysms

Long-term surgical results with aneurysms involving the ophthalmic segment of the carotid artery

Object

Because of the anatomical complexity of the paraclinoid region, the surgical treatment of aneurysms arising in the C6 segment of the internal carotid artery is extremely challenging. The authors' aim in this study was to describe the extended clinical follow-up and assess the short-term and long-term effectiveness of surgical treatment for these aneurysms, focusing on the clinical outcome and degree of aneurysm occlusion and recurrence.

Methods

The authors retrospectively analyzed the clinical records for patients treated surgically between 1973 and 2004 at the University of Rome, “La Sapienza.” Aneurysms were classified into the following 3 groups according to the site where they arose: the anteromedial, anterior or anterolateral, and posteromedial wall of the C6 segment.

Results

Of the 108 aneurysms in 104 patients treated, 63 (58%) were large or giant. Eighty-eight aneurysms in 84 patients were clipped, 16 underwent a high-flow bypass, 2 were trapped, 1 was wrapped, and 1 was left untreated. The mean follow-up was 126 months; 47 patients had a follow-up of > 10 years. Of the 88 aneurysms that were clipped, 6 (6.8%) had an incomplete occlusion that required an immediate reoperation in 1 case and at 2 years in another. Overall 6 patients (5.8%) had surgery-related permanent complications.

Conclusions

Mortality and morbidity rates depend mainly on the patient's preoperative Hunt and Hess grade subarachnoid hemorrhage, whereas surgical morbidity principally reflects excessive manipulation of the optic nerve or ischemic problems due to excessive temporary trapping undertaken without adequate neuroprotection. In expert hands, surgery (clipping and bypass procedures) is a definitive treatment for C6 aneurysms and has an acceptable complication rate.

Ruptured internal carotid artery anterior wall aneurysm identified during vasospasm: case report

OBJECTIVE AND IMPORTANCE

Aneurysms of the paraclinoid segment arising from the anterolateral wall of the proximal internal carotid artery (ICA) are usually located in the intradural space, and the proximal neck of the aneurysm is closely adjacent to the dural ring. Although most of these aneurysms can be identified by cerebral angiography, the top of the aneurysm can be flattened because of its relationship to the undersurface of the clinoid process. We report a rare case of a ruptured ICA anterolateral wall aneurysm that was not identified by initial angiography but was clearly observed at the time of vasospasm.

CLINICAL PRESENTATION

A 59-year-old female patient was transferred to our hospital because of sudden loss of consciousness. Initial angiography failed to disclose any aneurysm except for one projecting to the right at the C3-C4 portion of the left ICA. A left frontotemporal craniotomy with drilling of the anterior clinoid process was performed 1 day after the onset of subarachnoid hemorrhage. Within the operative field, however, no hemorrhage was detected near the C3-C4 portion of the left ICA. Subsequent angiography performed during vasospasm clearly demonstrated a ruptured aneurysm in the anterior paraclinoid segment of the right ICA.

INTERVENTION

After drilling the anterior clinoid process and cutting the dural ring, we successfully clipped the aneurysm. The aneurysm was saccular, with a broad neck that extended below the dural ring. Intraoperative inspection demonstrated that the dome of the aneurysm was in a subclinoid location, suggesting that most of the aneurysm might have been flattened by the dural ring at the time of initial angiography but before the onset of vasospasm.

CONCLUSION

The presented case suggests that this type of aneurysm may be missed by routine angiography performed before and after vasospasm. If initial angiography fails to reveal the origin of the subarachnoid hemorrhage but computed tomography still discloses hemorrhage from an ICA aneurysm, repeated angiography should be considered within 14 days after the onset of subarachnoid hemorrhage to confirm whether the aneurysm has arisen from the anterior clinoid segment of the ICA.