Unruptured intracranial aneurysms: natural history, clinical outcome, and risks of surgical and endovascular treatment.

BACKGROUND: The management of unruptured intracranial aneurysms is controversial. Investigators from the International Study of Unruptured Intracranial Aneurysms aimed to assess the natural history of unruptured intracranial aneurysms and to measure the risk associated with their repair. METHODS: Centres in the USA, Canada, and Europe enrolled patients for prospective assessment of unruptured aneurysms. Investigators recorded the natural history in patients who did not have surgery, and assessed morbidity and mortality associated with repair of unruptured aneurysms by either open surgery or endovascular procedures. FINDINGS: 4060 patients were assessed-1692 did not have aneurysmal repair, 1917 had open surgery, and 451 had endovascular procedures. 5-year cumulative rupture rates for patients who did not have a history of subarachnoid haemorrhage with aneurysms located in internal carotid artery, anterior communicating or anterior cerebral artery, or middle cerebral artery were 0%, 2. 6%, 14 5%, and 40% for aneurysms less than 7 mm, 7-12 mm, 13-24 mm, and 25 mm or greater, respectively, compared with rates of 2 5%, 14 5%, 18 4%, and 50%, respectively, for the same size categories involving posterior circulation and posterior communicating artery aneurysms. These rates were often equalled or exceeded by the risks associated with surgical or endovascular repair of comparable lesions. Patients' age was a strong predictor of surgical outcome, and the size and location of an aneurysm predict both surgical and endovascular outcomes. INTERPRETATION: Many factors are involved in management of patients with unruptured intracranial aneurysms. Site, size, and group specific risks of the natural history should be compared with site, size, and age-specific risks of repair for each patient.

Cerebrovascular manifestations in 321 cases of hereditary hemorrhagic telangiectasia.

BACKGROUND AND PURPOSE: Patients with hereditary hemorrhagic telangiectasia (HHT) are at risk for developing cerebral vascular malformations and pulmonary arteriovenous fistulae. We assessed the risk of neurological dysfunction from these malformations and fistulae. METHODS: Three hundred twenty-one consecutive patients with HHT seen at a single institution over a 20-year period were studied. Any evidence of prior neurological symptoms or presence of an intracranial vascular malformation was recorded. All cases of possible cerebral arteriovenous malformation were confirmed by conventional arteriography. RESULTS: Twelve patients (3.7%) had a history of cerebral vascular malformations. Ten patients had arteriovenous malformations, 1 had a dural arteriovenous fistula, and 1 had a cavernous malformation. Seven patients (2.1%) presented with intracranial hemorrhage, 2 presented with seizures alone, and 3 were discovered incidentally. The average age at the time of symptomatic intracranial hemorrhage was 25.4 years. All patients with a history of intracranial hemorrhage were classified as Rankin grade I or II at a mean follow-up interval of 6.0 years. A history of cerebral infarction or transient ischemic attack was found in 29.6% of patients with HHT and a pulmonary arteriovenous fistula. CONCLUSIONS: The risk of intracranial hemorrhage is low among people with HHT. Furthermore, a majority of these patients have a good functional outcome after hemorrhage. The data do not suggest a compelling indication for routine screening of patients with HHT for asymptomatic cerebral vascular malformations. By comparison, pulmonary arteriovenous fistulae are a much more frequent cause of neurological symptoms in this population.

Weakness of the lower extremity in carotid occlusive disease.

Nineteen patients experienced progressive or episodic weakness of one lower extremity caused by severe stenosis or occlusion of the internal carotid artery. The majority of patients (84.2%) had occlusion or severe stenosis at the origin. Based on clinical profiles, angiographic findings, and cerebral blood flow patterns, we concluded that the pathophysiologic mechanism was hypoperfusion in the border zone between the anterior cerebral artery and the middle cerebral artery and that patients with progressive weakness had more extensive compromise in cerebral circulation. Following surgical treatment in 17 patients, progressive and episodic weakness disappeared and the majority of them (76.4%) became asymptomatic. However, the patients with stenosis at the siphon and those with progressive weakness from occlusion at the origin appeared to be at increased risk for cardiac death.

Brief loss of consciousness in bilateral carotid occlusive disease.

Loss of consciousness is rare in the absence of transient or persistent insult to the diencephalon or mesencephalon. We found three patients with severe atherosclerotic stenosis or occlusion of both internal carotid arteries who experienced brief loss of consciousness. Common characteristics were the absence of clinical or electroencephalographic seizure activities, significant cardiovascular disease, or a history suggestive of vasovagal syncope. Angiographically, the patients had widely patent vertebrobasilar circulation and collaterals from vertebrobasilar to carotid circulation. Episodic loss of consciousness disappeared after carotid endarterectomy. We concluded that bilateral hemispheric ischemia caused brief loss of consciousness, but selective focal ischemia in the subcortical structures superimposed on widespread bihemispheric ischemia may have been responsible. Since loss of consciousness is rare in carotid occlusive diseases, systemic and vertebrobasilar causes must be carefully ruled out in each instance.

Cervical internal carotid artery aneurysm with calcific embolism to the retina.

A patient with an arteriosclerotic aneurysm of the cervical portion of the internal carotid artery presented with calcific retinal embolization. Aneurysms of the extracranial portion of the internal carotid artery are uncommon, and this mode of presentation has not been reported previously.

Hemifacial spasm associated with epidermoid tumors of the cerebellopontine angle.

Hemifacial spasm (HFS) is rarely due to serious compressive lesions, such as tumors, aneurysms, or vascular malformations, located in the cerebellopontine angle. Because of the interesting association of HFS with epidermoid tumors, we reviewed the records of all patients with HFS and all patients with intracranial epidermoid tumors seen from January 1975 to December 1986. Of the 18 patients who had epidermoid tumors of the cerebellopontine angle, 3 (17%) had a facial movement disorder that resembled HFS at sometime during their illness. There were 429 patients who had HFS with no obvious serious compressive lesion of the facial nerve. Therefore, HFS was associated with epidermoid tumor in 0.7% of cases. All 3 patients developed other findings due to involvement of adjacent neural structures. Patients with HFS have a low probability of having a serious compressive lesion, but those with atypical features should be evaluated for cerebellopontine angle masses such as epidermoid tumors.

Absent headache despite CSF volume depletion (intracranial hypotension).

CSF volume depletions, whether from leak or shunt overdrainage, typically cause low CSF opening pressures, orthostatic headaches, and diffuse pachymeningeal gadolinium enhancement on MRI. The authors report three patients-two with overdraining CSF shunts and one with proven CSF leak-with the typical pachymeningeal enhancement but without headaches. In CSF leaks and CSF shunt overdrainage, like MRI abnormalities and CSF alterations, the clinical features also show considerable variability. The independent variable remains the CSF volume depletion.

Spontaneous dissections of cervicocephalic arteries in childhood and adolescence.

Among 263 consecutive patients with spontaneous cervicocephalic arterial dissections evaluated at the Mayo Clinic, 18 (6.8%) were 18 years of age or younger (mean age, 12 years). The dissection involved the cervical arteries in 11 patients and the intracranial arteries in seven. Extracranially, the internal carotid artery was involved in eight patients, the vertebral artery in two, and both arteries in one. Intracranially, only the anterior circulation was affected. All the patients had cerebral or retinal ischemic symptoms, usually preceded by headache. Death occurred in a 13-year-old boy with intracranial arterial dissection and coarctation of the aorta. For the 17 remaining patients, the follow-up period ranged from 1 to 21 years. A complete or good clinical recovery occurred in 10 of the 11 patients with cervical arterial dissection but in only four of the seven with dissection of intracranial arteries. Recurrent arterial dissection occurred in two patients with cervical arterial dissections and in one patients with intracranial arterial dissection.

Spontaneous dissections of the vertebral arteries.

Clinical and angiographic features and outcome in 25 patients with spontaneous dissections of the vertebral arteries are described. Most patients were in their fourth or fifth decade of life, and women predominated. Forty-eight percent of the patients were hypertensive. Angiographic evidence of fibromuscular dysplasia was noted in one only. Brainstem ischemic symptoms (usually a lateral medullary syndrome) and ipsilateral occipital headache and neck pain (often preceding but sometimes associated with or following the brainstem ischemic event) were the most common clinical findings. The angiographic features in decreasing order of frequency were luminal stenosis (often irregular and tapered), aneurysm, occlusion, and intimal flap. On follow-up, most of the patients (88%) made complete or very good recoveries. Angiographic abnormalities either subsided or improved in 76%. Multivessel dissection (involvement of both vertebral arteries or one or both vertebral arteries and one or both internal carotid arteries) was noted in about two-thirds of the patients. This tendency of vertebral artery dissections to involve multiple cervicocephalic vessels concurrently, if not simultaneously, implies that four-vessel angiography should be attempted if a vertebral artery dissection is visualized. It also raises the possibility of an underlying arteriopathy that predisposes the vessel to dissection.

Orthostatic headaches caused by CSF leak but with normal CSF pressures.

OBJECTIVE: To report that the syndrome of orthostatic headaches caused by CSF leak can be seen with persistently normal CSF pressures. BACKGROUND: CSF leak or shunt overdrainage is known to cause orthostatic headaches and diffuse pachymeningeal gadolinium enhancement (DPGE), typically associated with unmeasurable or very low CSF pressures. METHODS: Of 40 consecutive patients with orthostatic headaches and DPGE, all had low or unmeasurable CSF pressures, except seven patients who had consistently normal CSF pressures and are thus reported. All had undergone multiple CSF examinations. RESULTS: Two patients had overdraining shunts, and five had documented CSF leaks. One refused treatment, but the other six patients responded to surgical treatment or epidural blood patch with complete resolution of symptoms and related MRI abnormalities. CONCLUSIONS: Some patients with symptomatic CSF leaks may have CSF opening pressures that are consistently within normal limits. In the presence of convincing clinical features and imaging abnormalities, a normal CSF pressure should not discourage the clinician from searching for a source of CSF leak.

Cranial nerve palsy in spontaneous dissection of the extracranial internal carotid artery.

Cranial nerve palsy was present in 23 of 190 consecutive adult patients (12%) with spontaneous dissection of the extracranial internal carotid artery. Ten patients (5.2%) had a syndrome of lower cranial nerve palsies (with invariable involvement of cranial nerve XII with or without additional involvement of cranial nerves XI, X, and IX), seven (3.7%) had palsy of cranial nerve V, and five (2.6%) had a syndrome of ocular motor palsies. Palsy of cranial nerve VIII and ischemic optic neuropathy occurred in one patient each. Three patients had dysgeusia without other cranial nerve involvement, presumably due to involvement of the chorda tympani nerve. Headache or face pain (often unilateral) was present in 83% of patients. Other associated manifestations were cerebral ischemic symptoms, bruits, or oculosympathetic palsy. In one patient, cranial nerve palsy was the only manifestation of internal carotid artery dissection, and in another patient, the disease presented only as a palsy of cranial nerve XII and oculosympathetic palsy. In six patients, a syndrome of hemicrania and ipsilateral cranial nerve palsy was the sole manifestation of internal carotid artery dissection. Cranial nerve palsy is not rare in internal carotid artery dissection. Compression or stretching of the nerve by the expanded artery may explain some but not all of the palsies. An alternative mechanism is likely interruption of the nutrient vessels supplying the nerve.

Ocular motor nerve palsies in spontaneous dissections of the cervical internal carotid artery.

Cranial nerve palsies affecting ocular motor function in patients with spontaneous cervical internal carotid artery dissections are rare. Among 155 patients with spontaneous dissections of the cervical internal carotid artery, four (2.6%) had transient third, fourth, or sixth cranial nerve palsy. The third nerve was involved in two patients, the fourth nerve in one, and the sixth nerve in one. Three patients had ipsilateral headache or facial pain, one had bilateral headaches, and three had oculosympathetic palsy. None had any associated cerebral or retinal ischemic symptoms. Cervical internal carotid artery dissection should be included in the differential diagnosis of palsies of the third, fourth, or sixth cranial nerve, especially when associated with ipsilateral headache or facial pain. Interruption of the nutrient arteries supplying these cranial nerves could explain their involvement by internal carotid artery dissection.

Meningeal biopsy in intracranial hypotension: meningeal enhancement on MRI.

Intracranial hypotension is a cause of diffuse enhancement of the pachymeninx with gadolinium, which often is associated with subdural fluid collections. We reviewed the results of meningeal biopsy in six patients with intracranial hypotension and diffuse pachymeningeal enhancement to correlate the MRI findings with histopathologic observations and to explain the abnormalities seen on MRI. Grossly, the dura mater was unremarkable in all patients, as were the leptomeninges, except for one patient with prolonged (18 months) intracranial hypotension in whom the arachnoid was thickened and opaque. Microscopically, the dura mater was entirely normal on its epidural aspect; however, a fairly thin zone of fibroblasts and thin-walled small blood vessels in an amorphous matrix was noted on the subdural aspect. In the patient with longstanding symptoms, diffuse benign arachnoidal cell proliferation was also noted, probably a reaction triggered by longstanding changes in the subdural area, as noted in the five other patients. There was no evidence of inflammation, infection, or metastatic neoplasia. These findings suggest that in intracranial hypotension, the dural-meningeal abnormalities probably represent reactive secondary phenomena, likely related to hydrostatic changes in the CSF, and not a primary meningeal process.

Sudden death from aneurysmal subarachnoid hemorrhage.

Some patients with aneurysmal subarachnoid hemorrhage (SAH) never reach the hospital alive ("sudden death") and, although their numbers are significant, they are not included in most studies of SAH. To clarify the clinical profile of sudden death from aneurysmal SAH, we reviewed the epidemiology and clinicopathologic features of patients with aneurysmal SAH who never reached medical attention. Using the medical record linkage system employed for epidemiologic studies for the population of Rochester, Minnesota, we identified all patients who were diagnosed with aneurysmal SAH between 1960 and 1989. There were 80 women and 33 men with a mean age of 55 years. Of these 113 patients, 13 (12%) died without reaching medical attention. The proportion of those with sudden death remained stable during the study period. In comparing patients with sudden death with those who reached medical attention, the only significant variable was the frequency of posterior circulation aneurysms that was found in 38%, compared with 14% in those who received medical attention (p = 0.042). At autopsy, intraventricular hemorrhage was present in 12 patients (92%) with sudden death, and intracerebral hemorrhage was present in two (15%). Twelve patients (92%) had acute pulmonary edema. In our community, the frequency of sudden death from aneurysmal SAH has not changed during the last three decades in spite of the advances in medical care. The typical clinical profile of sudden death in SAH includes intraventricular hemorrhage, pulmonary edema, and a ruptured posterior circulation aneurysm. Intracerebral hemorrhage is uncommonly associated with sudden death from aneurysmal SAH.

Absent pachymeningeal gadolinium enhancement on cranial MRI despite symptomatic CSF leak.

CSF leak is recognized to cause orthostatic headaches and diffuse pachymeningeal gadolinium enhancement (DPMGE) on MRI. We report six patients with typical symptoms and documented CSF leaks without DPMGE. Two had normal meninges from the onset; one initially had normal meninges, but subsequently DPMGE developed. In three, the initially noted DPMGE resolved while they were still symptomatic with documented continued CSF leaks. Absent DPMGE does not rule out CSF leak. When clinical manifestations suggest this disorder, additional diagnostic studies should be pursued.

Acute deterioration from thrombosis and rerupture of a giant intracranial aneurysm.

The authors describe a patient with an unusual clinicopathologic picture of giant aneurysmal hemorrhage followed by sudden deterioration due to acute intra-aneurysmal thrombosis and fatal rebleeding. This patient underscores the poor natural history associated with this devastating disease and serves to highlight the dangers inherent in the delayed treatment of these life-threatening lesions.

Microvascular decompression of the facial nerve for hemifacial spasm: clinical and electrophysiologic observations.

Eight patients with idiopathic hemifacial spasm were studied before and after decompression of the facial nerve. Seven patients had an excellent clinical response to surgery, with total resolution of the spasm. One patient had a complete facial palsy and sensorineural deafness on the involved side after surgery, with recurrence of the spasm 6 months later. In all patients, synkinetic activity was present on the involved side before surgery and disappeared after surgery. These findings suggest that the disorder involves the extra-axial portion of the facial nerve. The findings do not require an etiologic role of vascular compression because the response to surgery could be related either to mild trauma of the nerve during the surgical procedure or to subsequent fibrosis.

Small cerebral aneurysms presenting with symptoms other than rupture.

BACKGROUND: Recent natural history studies have suggested that unruptured intracranial aneurysms smaller than 1 cm have a low risk of rupture. Symptomatic aneurysms may be underrepresented in natural history studies because they are preferentially treated. The authors compared the number of patients with symptoms caused by unruptured intracranial aneurysms smaller than 1 cm treated surgically at their institution with similar patients enrolled in the International Study of Unruptured Intracranial Aneurysms (ISUIA) from their institution over the same time period. METHODS: The records of all unruptured aneurysms treated surgically at the Mayo Clinic from 1980 through 1991 were reviewed. There were 97 patients with 117 unruptured aneurysms smaller than 1 cm by angiography. Aneurysms with a history of rupture or larger than 1 cm on cross-sectional imaging were excluded from analysis. The presence and characteristics of symptoms directly attributable to the aneurysm were recorded. Comparison was made with patients from the Mayo Clinic enrolled in the ISUIA retrospective natural history cohort over the same time period. RESULTS: Of the 97 patients studied, 15 presented with symptoms other than rupture (15.5%). The symptoms were third nerve deficit (seven patients), cerebral ischemia owing to emboli originating from within the aneurysm (five patients), and visual acuity loss (three patients). Eleven other aneurysms had possibly but not definitively caused symptoms; these were considered asymptomatic. No patient from the Mayo Clinic enrolled in the retrospective cohort of the ISUIA had a symptomatic aneurysm smaller than 1 cm on both angiography and cross-sectional imaging. CONCLUSIONS: Unruptured intracranial aneurysms smaller than 1 cm occasionally present with neurologic symptoms. These symptoms are typically owing to mass effect on the second and third cranial nerves or cerebral ischemia as a result of emboli originating from within the aneurysm. Patients with symptomatic unruptured aneurysms less than 1 cm at the Mayo Clinic were preferentially treated. Although existing natural history data may be applied to most unruptured aneurysms, small symptomatic aneurysms may be underrepresented in natural history studies.

Syndrome of orthostatic headaches and diffuse pachymeningeal gadolinium enhancement.

OBJECTIVE: To characterize clinical and imaging features, biopsy findings, etiologic factors, and outcome in the syndrome of intracranial hypotension, headaches, and diffuse pachymeningeal gadolinium enhancement on magnetic resonance imaging (MRI). MATERIAL AND METHODS: We describe our experience with 26 consecutive patients with orthostatic headaches and diffuse pachymeningeal gadolinium enhancement, for all of whom clinical, imaging, and follow-up data were available. For 10 patients who had undergone meningeal biopsy, slide material was also reviewed. RESULTS: The 15 men and 11 women ranged from 24 to 76 years of age. All 26 patients had postural headaches; in 22 patients, the headaches were completely alleviated by recumbency. Nausea or emesis, neck pain, horizontal diplopia, changes in hearing, photophobia, upper limb pains or paresthesias, visual blurring, or dysgeusia was noted in some of the patients. Cardinal MRI features were diffuse pachymeningeal gadolinium enhancement (100%), subdural collections of fluid (69%), and evidence of descent of the brain (62%) that sometimes resembled type I Chiari malformation. Cerebrospinal fluid (CSF) opening pressures were 40 mm or less in only 46%. In three patients, CSF pressures were consistently no less than 90 and as high as 130 mm of water. A variable pleocytosis of 5 or more cells/mm3 was noted in 15 patients (more than 40 cells/mm3 in 4 patients). A variable increase in CSF protein was noted in at least one spinal tap in 23 patients. Six patients had overdraining CSF shunts; CSF leak was documented in another 11 patients. Shunt revision or ligation and surgical correction of the leak led to a resolution of the clinical and MRI abnormalities in all cases thus treated. Improvement occurred with epidural blood patch in four patients. Three of the 12 patients treated supportively have remained symptomatic. Histologically, a thin subdural zone of fibroblasts and thin-walled vessels was noted in an amorphous matrix. Two patients with prolonged symptoms had a more pronounced proliferative reaction. CONCLUSION: The syndrome of low-pressure headaches and pachymeningeal gadolinium enhancement is being recognized with increasing frequency. The source of the CSF leak can be demonstrated in many patients. Meningeal abnormalities are likely attributable to decreased CSF volume and hydrostatic CSF pressure changes. The prognosis is typically good.

Hemifacial spasm: results of microvascular decompression of the facial nerve in 54 patients.

During the 10-year period between January 1975 and December 1984, 367 patients with hemifacial spasm were examined at our institution. Because of the severity of the spasm, 54 patients underwent surgical management that consisted of microvascular decompression of the facial nerve. Postoperatively, the hemifacial spasm was completely resolved in 44 patients (81%), but 6 of these patients had subsequent recurrence of the condition. An additional five patients (9%) experienced improvement but were not totally free of the spasm. Five patients (9%) received no benefit from the procedure. Complications occurred in 19 patients (35%) but were usually transient. The most serious complication was permanent ipsilateral hearing loss, which occurred in eight patients (15%). Thus, in general, microvascular decompression of the facial nerve effectively alleviates hemifacial spasm.