ANEURYSM OF THE INTRACRANIAL CAROTID ARTERY

RCTs in determining treatment indications for intracranial aneurysms: What can we learn from history?

BACKGROUND AND PURPOSE

Many important issues regarding the management of intracranial aneurysms remain controversial. We review the role played by randomized trials in the determination of the best management of intracranial aneurysms in the early era of surgical clipping.

METHODS

Landmark trials and cooperative studies are analyzed and results summarized in a narrative review.

RESULTS

The most convincing evidence in favour of surgical management of ruptured intracranial aneurysms came from early randomized trials conducted from the 1950s to 1970s. Large historical observational studies, performed between the 1970s and 2000, aiming to guide clinical practice, provided only statistical associations mixed with confounding variables. After the early RCTs, the next important gain in reliable knowledge occurred with completion of the ISAT trial, more than 25 years later.

CONCLUSION

The pioneering neurosurgeons of early trials can provide the inspiration necessary to make real progress in understanding the best clinical management of intracranial aneurysms.

"Mirror-image" bilateral giants: intracavernous carotid artery aneurysms

SUMMARY

The literature on the incidence of "mirror image" bilateral giant intracavernous aneurysms, their symptoms and their association with other entities is reviewed, with a brief comment on their evolution and treatment. A case of "mirror image" bilateral giant intracavernous aneurysms in a 76-year-old man who presented a sudden diplopia with pupillary sparing is reported. A CT scan showed parasellar images and dolichomega circle of Willis arteries that enhanced with endovenous contrast. MRI and angiography disclose bilateral aneurysms in detail, associated with an anomalous origin of the left common carotid artery and bilateral renal artery stenosis.

Acute subdural hematoma caused by a ruptured giant intracavernous aneurysm: case report

A case of a giant intracavernous carotid artery aneurysm that presented as an acute subdural hematoma is reported. The patient was initially treated unsuccessfully with endovascular aneurysmal embolization and subsequently underwent attempted microsurgical clipping with preservation of the parent artery. At operation, an angiogram showed occlusion of the parent vessel, and the aneurysm was trapped by occlusion of the internal carotid artery. The patient did well for 2 days postoperatively but then developed contralateral progressive hemiplegia and aphasia. Emergent subsequent exploration and middle cerebral artery embolectomy were performed, and the hemiplegia and aphasia resolved rapidly. At 2-year follow-up, the patient continues to do well. To our knowledge, this is the first reported case of a patient who survived an acute subdural hematoma caused by an intracavernous carotid artery aneurysm.

Intracranial aneurysms with superior division paresis of the oculomotor nerve

Five patients with intracranial aneurysms had unilateral ptosis, limitation of supraduction, and normal pupillary reactivity. The most common aneurysm location for superior division paresis of the oculomotor nerve was the superior cerebellar-posterior cerebral artery junction, where aneurysms (3) of the basilar artery compressed and flattened the interpeduncular oculomotor nerve from below. A superior cerebellar artery aneurysm and brain stem infarction affected the intra-axial course of the oculomotor nerve producing superior division paresis. Only an aneurysm of the intracavernous carotid artery resulted in superior division paresis at the expected anatomic site of bifurcation of the oculomotor nerve into its superior and inferior divisions. Because the superior division supplies innervation exclusively to the superior rectus muscle and levator palpebrae, an aneurysm involving this branch does not affect the pupillo-constrictor fibers. Consequently, cerebral angiography should be considered in the initial evaluation of this ocular motor deficit.

Pupil-sparing oculomotor palsies with internal carotid-posterior communicating artery aneurysms

The charts of 84 patients admitted to the Neurosurgery Service of the Washington University Medical Center between January, 1960, and July, 1981, with aneurysms at or near the junction of the internal carotid and posterior communicating arteries (ICA-PoCA) were reviewed. Special emphasis was placed on the pupillary size and reactivity of 51 patients with oculomotor nerve involvement. Seven initially had normal pupils, representing 8% of the total group and 14% of those presenting with oculomotor palsies. In 4 of these patients pupillary involvement developed within 5 days, and in 1 pupillary involvement developed in 4 months. Pupillary sparing appears to be more common than previously appreciated in patients with ICA-PoCA aneurysms and oculomotor nerve involvement. Patients with acute somatic oculomotor paresis should be observed closely for at least one week for the development of pupillary involvement. Arteriography may be indicated more frequently than previously recommended.

Prognosis of oculomotor palsy in patients with aneurysms of the posterior communicating artery

In patients with symptomatic aneurysms of the posterior communicating artery, the prognosis of oculomotor palsy mainly depends on the interval between the onset of palsy and the time of operation, and furthermore on the degree of preoperative deficit and the development of the cranial nerve lesion. The incidence of ultimately complete or incomplete palsy is the same in cases with subarachnoid haemorrhage and without rupture ("warning symptom"). In many cases, an initially incomplete paresis develops to a complete ocular palsy within eight days. Ptosis is generally the first symptom, and it frequently shows the earliest recovery of all other disturbed oculomotor functions after surgery. Full recovery of oculomotor palsy occurs usually only in those patients who undergo early clipping of an aneurysm, i.e. mainly within 10 days after onset of ocular palsy. Complete restitution after carotid ligation is possible, but rare. In cases with full recovery, restitution occurs mostly within three months, sometimes even within a few weeks. An improvement in oculomotor palsy is still possible after a year, but ultimately in these patients recovery remains always more or less incomplete. Incomplete restitution of a third cranial nerve lesion is very often associated with aberrant regeneration and subsequent synkinetic ocular movement. The restitution of the single ocular muscle functions shows a fairly constant course: the levator palpebrae muscle and the M. rectus medialis show rapid recovery. The parasympathetic fibres follow next, but normal function of elevation and depression of the ocular bulb (M. rectus sup., M. obliquus inf. and M. rectus inf.) is often delayed.

Aneurysms of the posterior communicating artery and oculomotor paresis

One hundred and seventy-four patients with a posterior communicating aneurysm were seen over a 21 year period. There was a ratio of four females to one male and women were on average five years older. Fifty-nine (34%) had an oculomotor paresis. This group had up to four attacks of localized headache, large multiloculated aneurysms, and a greater time lapse from the onset of symptoms to surgery compared with those patients without oculomotor palsy. Delay in treatment allowed further attacks to occur which increased the mortality rate and decreased the chance that the eye would recover. Eighteen people who had had a palsy before craniotomy two to 18 years previously were examined. In four (22%) the paralysis had recovered completely, 14 (78%) had greatly reduced oculomotor function, and nine (50%) showed aberrant regeneration of the nerve. Nine of 62 patients, seven of whom were seen, developed a palsy after craniotomy and in five the eye had returned to normal.

The surgical treatment of bleeding intracranial aneurysms

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Arteriography and carotid artery ligation in intracranial aneurysm and vascular malformation

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