Toward an endovascular internal carotid artery classification system.

SUMMARY: Does the world need another ICA classification scheme? We believe so. The purpose of proposed angiography-driven classification is to optimize description of the carotid artery from the endovascular perspective. A review of existing, predominantly surgically-driven classifications is performed, and a new scheme, based on the study of NYU aneurysm angiographic and cross-sectional databases is proposed. Seven segments - cervical, petrous, cavernous, paraophthlamic, posterior communicating, choroidal, and terminus - are named. This nomenclature recognizes intrinsic uncertainty in precise angiographic and cross-sectional localization of aneurysms adjacent to the dural rings, regarding all lesions distal to the cavernous segment as potentially intradural. Rather than subdividing various transitional, ophthalmic, and hypophyseal aneurysm subtypes, as necessitated by their varied surgical approaches and risks, the proposed classification emphasizes their common endovascular treatment features, while recognizing that many complex, trans-segmental, and fusiform aneurysms not readily classifiable into presently available, saccular aneurysm-driven schemes, are being increasingly addressed by endovascular means. We believe this classification may find utility in standardizing nomenclature for outcome tracking, treatment trials and physician communication.

Improvement of chronic hearing loss after shunt revision. A case report.

BACKGROUND: Hearing loss after intracranial and spinal procedures involving cerebrospinal fluid loss is rarely reported in the literature. We report a patient who suffered from delayed hearing loss after cerebrospinal fluid shunting that improved after revising the shunt to a higher-pressure valve. CASE DESCRIPTION: A 32-year-old woman presented with bilateral hearing loss 4 years after ventriculoperitoneal shunting for communicating hydrocephalus. Her otologic work-up revealed sensorineural hearing loss. In an attempt to improve her hearing, 6 years after the hearing loss began (10 years after the shunt was placed), she underwent a shunt revision in which her valve was changed to a higher-pressure device. After the procedure, she had a significant improvement in her speech discrimination and a mild improvement in her pure tone recognition. These changes were documented with serial audiograms. CONCLUSION: Hearing loss after cerebrospinal shunting procedures is not always limited to the immediate postoperative period. It may be a late complication of cerebrospinal fluid diversion. Chronic hearing loss after ventriculoperitoneal shunting may be treatable by changing the valve to a higher-pressure device. The etiology of hearing loss from intracranial hypotension is briefly discussed.

Familial arteriovenous malformations in siblings.

BACKGROUND: Familial arteriovenous malformations (AVMs) of the brain are rare. We present two sisters with the same parents who harbored AVMs that were successfully treated. METHODS: The elder sister presented with a unilateral migrainous type of headache overlying the right parietal area. The younger one suffered from exercise-induced headaches. Both were neurologically intact. Magnetic resonance imaging scans of the brain and cerebral angiography delineated the lesions. Both sisters underwent endovascular embolization followed by surgical resection. RESULTS: Postoperatively, aside from a left inferior quadrantanopsia in the elder sister, both were neurologically intact. CONCLUSIONS: We report the rare occurrence of familial AVMs in two siblings and review the literature of 14 reports. No genetic predisposition was found.

Surgical treatment of carotid cavernous aneurysms.

Carotid cavernous aneurysms are distinct entities. The anatomy of the cavernous sinus region has been well defined, and most spontaneous aneurysms of the cavernous sinus region carry a benign prognosis. Progressively symptomatic, traumatic, or infectious aneurysms require treatment. This can be accomplished by carotid occlusion, extra cranial to intracranial bypass, or direct surgery.

A dissecting aneurysm of the posteroinferior cerebellar artery: case report.

OBJECTIVE AND IMPORTANCE: We present a patient who experienced a subarachnoid hemorrhage secondary to a dissecting aneurysm of the right posteroinferior cerebellar artery (PICA). The use of an encircling clip in treating the aneurysm while preserving supply to brain stem perforators originating near the dissecting segment and the distal PICA territory was key in the operative management. CLINICAL PRESENTATION: A 48-year-old patient with a history of hypertension presented with subarachnoid hemorrhage confirmed by computed tomography of the brain. Successive cerebral angiography revealed a dynamic change in the configuration of the dissection, with expansion of the associated focal ectasia. OPERATIVE MANAGEMENT: At surgery, three brain stem perforators adjacent to the aneurysm were visualized. The dissecting segment was reconstructed with an encircling Sundt clip and muslin wrap, which preserved the flow through the PICA and brain stem perforators. CONCLUSION: A patient suffering from a dissecting PICA aneurysm and subarachnoid hemorrhage was successfully treated with direct surgical reconstruction of the parent artery, sparing the perforators to the medulla.

Traumatic posterior cerebral artery aneurysm secondary to an intracranial nail: case report.

We present the case of a traumatic posterior cerebral artery aneurysm from a self-inflicted pneumatic nail-gun missile injury through the roof of the mouth. The patient presented to us in a coma with subarachanoid and intraventricular hemorrhage. Cerebral angiography revealed an aneurysm of the left posterior cerebral artery with no distal filling. The patient died 6 days after admission. At autopsy, a pseudoaneurysm of the posterior cerebral artery was seen. This aneurysm resulted from direct disruption of the arterial wall by the intracranial nail.

Acute surgical management of intracranial arteriovenous malformations.

The majority of intracranial arteriovenous malformations (AVMs) do not require acute surgical intervention. Some patients, however, require emergent surgical treatment because of a profound neurological deterioration from a mass effect. We report 10 patients who underwent emergency AVM surgery after experiencing neurological deterioration from an intracranial hemorrhage. Two patients bled spontaneously, whereas eight had an intracranial hemorrhage secondary to an embolization procedure. When the patients demonstrated neurological deterioration, they were intubated, hyperventilated, and underwent osmotic diuresis. Barbiturate anesthesia was initiated, and surgery was performed within 30 minutes in most cases. The hematomas were evacuated, and an attempt was made to excise the AVMs at the same time. Postoperatively, intracranial pressure was monitored, and barbiturate coma was maintained until the intracranial pressure returned to normal. Cerebral perfusion pressure was maintained above 55 mm Hg. The operation was confined to evacuating the hematoma in two patients with inoperable AVMs. The other eight patients underwent concomitant total AVM resection. Because of the severity of neurological deterioration, one patient who bled spontaneously underwent surgery based only on a computed tomographic scan of the brain. Nine patients made a good-to-excellent recovery. One patient with a large motor-strip AVM remained hemiplegic. We conclude that in patients presenting with profound neurological deterioration after a spontaneous intracranial hemorrhage or one associated with an embolization procedure, prompt hematoma evacuation with simultaneous AVM excision as well as perioperative intracranial pressure control with mannitol and barbiturates can yield a good-to-excellent outcome.

Surgery for angiographically occult cerebral aneurysms.

In 15% of patients with spontaneous subarachnoid hemorrhage (SAH), the source of bleeding cannot be determined despite repeated cerebral angiography. However, some patients diagnosed as having "SAH of unknown cause" actually harbor undetected aneurysms. The authors report six patients with SAH who, despite multiple negative cerebral angiograms, underwent exploratory surgery due to a high clinical and radiographic suspicion for the presence of an aneurysm. Brain computerized tomography (CT) scans revealed blood located mainly in the basal frontal interhemispheric fissure in four patients, in the sylvian fissure in one patient, and in the interpeduncular cistern in one patient. The patients were evaluated as Hunt and Hess Grades I to III, and had undergone at least two high-quality cerebral angiograms that did not reveal an aneurysm. Vasospasm was visualized in two patients. Three patients rebled while in the hospital. Exploratory surgery was performed at an average of 12 days post-SAH. Five aneurysms were discovered at surgery and were successfully clipped. All four patients with interhemispheric blood were found to have an anterior communicating artery (ACoA) aneurysm. The patient with blood in the sylvian fissure was found to have a middle cerebral artery aneurysm. These aneurysms were partially thrombosed. No aneurysm was detected in the patient with interpeduncular SAH, despite extensive basilar artery exploration. Five patients had an excellent outcome and one patient developed diabetes insipidus. These results show that exploratory aneurysm surgery is warranted, despite repeated negative cerebral angiograms, if the patient manifests the classical signs of SAH with CT scans localizing blood to a specific cerebral blood vessel (particularly the ACoA) and if a second SAH is documented at the same site.

The effect of embolization with N-butyl cyanoacrylate prior to surgical resection of cerebral arteriovenous malformations.

Endovascular therapy of cerebral arteriovenous malformations (AVM's) is an accepted adjunct to surgical therapy. However, the literature has not characterized the benefits or the liabilities of preoperative embolization. This series compares two groups of patients who underwent surgical resection of a cerebral AVM; one group (20 patients) received preoperative transfemoral selective embolization with N-butyl cyanoacrylate (NBCA) and the other group (13 patients) did not. In the group with preoperative embolization, the AVM's were larger (3.9 vs. 2.3 cm) and of a higher Spetzler-Martin grade (3.2 vs. 2.5) as compared to the nonembolized group. The NBCA embolization facilitated surgical resection. Arteries supplying the vascular malformation were readily distinguished from those supplying the normal brain parenchyma. Embolized vessels were compressible and easily cut with microscissors. No bleeding occurred from transected vessels. Operative time and intraoperative blood loss for the two groups were not statistically different, despite the significant differences in lesion size and grade. Endovascular complications included immediate and delayed hemorrhage (15%) and transient ischemia (5%); there were no embolization-related deaths. Postoperative complications for both groups included hemorrhage (15%), residual AVM (6%), and cerebrospinal fluid leak (3%); the mortality rate was 3%. There was no statistically significant difference in surgical complications between the embolized and nonembolized groups. Most patients (91%) in both groups had an excellent or good late neurological outcome, with no significant difference between the groups. This study concludes that preoperative NBCA embolization of AVM's makes lesions of larger size and higher grade the surgical equivalent of lesions of smaller size and lower grade by reducing operative time and intraoperative blood loss, with no statistically significant difference in surgical complications or long-term neurological outcome.

Intramedullary abscess associated with a spinal cord ependymoma: case report.

Intramedullary spinal cord abscesses are relatively uncommon. We report the first case of an intramedullary spinal cord abscess in a preexisting spinal cord ependymoma. The clinical features and pathogenesis are discussed. Salient features of the management of intramedullary spinal cord abscesses are outlined.

Tissue plasminogen activator thrombolysis of a middle cerebral artery embolus in a patient with an arteriovenous malformation. Case report.

A patient harboring a cerebral arteriovenous malformation (AVM) underwent angiography in an attempt to embolize the AVM. During catheterization (and prior to embolization) he became hemiplegic and aphasic. Angiography revealed a complete middle cerebral artery (MCA) occlusion by an embolus. The patient was treated with recombinant tissue plasminogen activator (t-PA), a thrombolytic agent. Restoration of MCA flow was achieved, and the patient recovered. Immediately after MCA embolus, t-PA infusion may lead to thrombolysis and neurological recovery. The decision-making process as well as the risks associated with the use of t-PA are discussed.

Selective platelet deposition during focal cerebral ischemia in cats.

Platelet deposition in the microcirculation may play a role in focal cerebral ischemia. We investigated platelet deposition in selected parts of the cat brain after temporary middle cerebral artery occlusion. Ten anesthesized cats were given autologous indium-111-labeled platelets and chromium-51-labeled erythrocytes. The right middle cerebral artery was occluded with miniature aneurysm clips for 3 hours via a transorbital approach; blood pressure was reduced concomitantly to decrease the collateral circulation. Removal of the clips initiated a 45-minute period of normotensive reperfusion. After sacrifice, the brain was removed and sectioned for comparison of right- versus left-hemisphere platelet deposition. Platelets were selectively deposited in the territory of the occluded right middle cerebral artery. Significant deposition was found in the caudate nucleus, internal capsule, parietal cortex, and the centrum semiovale. Our findings support the evidence that platelets are deposited in the microvasculature during temporary severe focal cerebral ischemia.

Multiple intracranial aneurysms: magnetic resonance imaging for determination of the site of rupture. Report of a case.

In a patient with multiple intracranial aneurysms, the clinical examination, computed tomographic brain scan, and cerebral angiogram failed to disclose which of five aneurysms had ruptured. Magnetic resonance imaging (MRI) revealed high signal intensity compatible with hemorrhage in the lower portion of one cerebellar tonsil, and a corresponding posterior inferior cerebellar artery aneurysm was successfully obliterated. We would add MRI to the list of useful adjuncts in identifying which of multiple aneurysms bled.

MRI in intraventricular neurocysticercosis: a case report.

A young Mexican female developed neurocysticercosis presenting as a lymphocytic meningoencephalitis with eosinophilia. Parasitic cysts in the fourth ventricle and pre-pontine cistern were well visualized by magnetic resonance imaging but not by computerized tomography. The meningoencephalitis recurred despite treatment with praziquantel and dexamethasone, and obstructive hydrocephalus eventually developed. The patient remains well one year after excision of the intraventricular cyst. This case emphasizes the distinct advantages of magnetic resonance imaging in the diagnosis of intraventricular neurocysticercosis, and the potential need for surgical rather than medical intervention in this condition.

Parasellar and optic nerve lesions: the neurosurgeon's perspective.

For neuroradiologic evaluation of parasellar lesions, a wide array of examinations may be utilized. CT and MRI are used in the assessment of these lesions to establish the diagnosis and to assist the neurosurgeon in defining the precise location. Careful neuroradiologic assessment and close cooperation between the neurosurgeon and the neuroradiologist have much bearing on the surgical planning and eventual outcome of the patient.

The effect of mannitol on cerebral blood flow.

The objective of this study was to evaluate the effects of mannitol, given over different time periods, on regional cerebral blood flow (rCBF) in patients with intracranial aneurysms. Seven patients with unruptured aneurysms (Group I) and 16 patients with Grade I and II subarachnoid hemorrhage (SAH) (Group II) received 1.5 gm/kg/8 hrs of 20% mannitol intravenously over a 24-hour period. Seven other patients with unruptured aneurysms (Group III) received 1.5 gm/kg of mannitol over 8 hours only. The last seven patients with unruptured aneurysms (Group IV) received the same dose, but as an intravenous bolus. Over a period of 24 hours, the patients underwent serial measurements of rCBF, intracranial pressure (ICP), mean blood pressure (MBP), cardiac output, and cerebral metabolic rate of oxygen consumption (CMRO2). Mannitol, when given as a continuous intravenous infusion, increased rCBF significantly without increasing MBP or decreasing ICP. This increase was more pronounced in SAH patients. The effects of mannitol lasted for 18 hours when given over an 8-hour period only; however, when it was given as a bolus, the increase in rCBF lasted for 24 hours, cardiac output tended to increase, and the effect on CMRO2 was variable.

Regional cerebral blood flow assessment prior to balloon detachment in the treatment of intracranial giant aneurysms.

Three patients with giant aneurysms (2 internal carotid and 1 anterior communicating) were treated by internal carotid occlusion with a detachable balloon. 133Xe regional cerebral blood flow (rCBF) was performed on each patient on admission. Due to low CBF, one patient received a superficial temporal artery--middle cerebral artery (STA-MCA) bypass. The rCBF was repeated when the balloon was inflated in the internal carotid prior to detachment of the balloon. All three patients were discharged within one week with no neurologic deficit. The rCBF assessment appears useful to decide which patient will tolerate acute balloon occlusion of the internal carotid and to help select patients who will need an extra-cranial-intracranial (EC-IC) bypass to avoid ischemic complication.