Cerebral embolic disease: a complication of carotid aneurysms

Management of Asymptomatic Vertebral Artery Injury Caused by a Cervical Pedicle Screw Malposition: Two Case Reports

Iatrogenic vertebral artery (VA) injury in cervical fusion is an extremely rare complication but can lead to serious sequelae. We present two successful cases of internal trapping for preventing delayed-onset ischemic stroke after iatrogenic VA stenosis caused by a cervical pedicle screw. A 34-year-old female underwent posterior cervical fusion for C4/C5 dislocation fracture. No neurological deficits were observed after the operation. However, the postoperative images revealed that the left C5 pedicle screw perforated the transverse foramen, and the left VA was suspected to be occluded at the screw insertion site. Before revision surgery, we tried to embolize the injured VA with coils. A microcatheter could be navigated from the ipsilateral VA to the distal of the screw, and internal trapping was performed with coils. Another case is that of a 50-year-old male with cervical spondylosis, who underwent posterior decompression and cervical fusion. The neurological symptoms did not deteriorate after the operation. However, the postoperative computed tomography images revealed the perforation of the right C3 transverse foramen by the pedicle screw. In right vertebral angiography, about 70% stenosis was observed at the screw insertion site. Although revision surgery was not planned due to good stability, we embolized the right VA after balloon occlusion test, to prevent the delayed-onset thromboembolic complications. Both the patients recovered without any neurological deficits. Iatrogenic VA injuries, even if asymptomatic immediately after surgery, can lead to serious sequelae in case of delayed-onset ischemic stroke. Therefore, careful attention should be paid when the screw perforates the transverse foramen.

Cerebral Ischemia as a Presenting Feature of Intracranial Aneurysms: A Negative Prognostic Indicator in the Management of Aneurysms

OBJECTIVE

Cerebral ischemia (stroke) can be a presenting clinical feature of intracranial aneurysms and may herald poor prognosis.

METHODS

A retrospective review of admissions for aneurysms over a 6-year period revealed that 12 patients (5%) had stroke or stroke-like presentations among 236 patients with intracranial aneurysms. Patient demographics, characteristics of aneurysms, and management were analyzed.

RESULTS

Of 12 patients reviewed, nine had anterior circulation aneurysms. Two patients presented with subarachnoid hemorrhage and 10 with unruptured aneurysms. Eleven patients had stroke at the time of presentation, and five had a previous history of transient ischemic attacks. Ten patients had hypertension and eight were active smokers. The mean size of 10 aneurysms was 11.8 mm. Surgical extirpation of the aneurysms was performed in all cases. Four cases revealed thrombus in the aneurysm and one was atherosclerotic. The 6-month outcome was good in seven patients (58%) and fair in four patients (33%). One patient died. This outcome was significantly worse (P < 0.01) compared to that of good grade aneurysms in our database. Hypertension was a significant indicator of poor outcome (P < 0.02).

CONCLUSION

Ischemic episodes as a presenting feature of intracranial aneurysms could be indicators of poor prognosis. Routine evaluation of stroke patients for aneurysms may help in early diagnosis. In addition, surgical obliteration of aneurysms could prevent subsequent strokes and neurological deficits.

Ischemic events associated with unruptured intracranial aneurysms: multicenter clinical study and review of the literature

OBJECTIVE

To determine the prevalence, clinical characteristics, and long-term outcomes in cases involving transient ischemic attacks (TIAs) or ischemic strokes secondary to embolization from unruptured intracranial aneurysms.

METHODS

We identified all available patients with intracranial aneurysms and ischemic strokes in three university-affiliated hospitals, using either International Classification of Diseases-9th Revision codes or local registries. Patients with clinically or radiologically detected cerebral infarctions distal to intracranial aneurysms, in the absence of other causes for the infarctions, were included. An aneurysmal embolic source was considered highly probable by the primary neurosurgeon/neurologist in all cases. Follow-up data for the patients were acquired through reviews of clinical visits or telephone interviews. A review of the literature was performed to identify characteristics of previously reported patients.

RESULTS

Ischemic strokes or TIAs attributable to embolization from the aneurysmal sac were observed for 9 of 269 patients (3.3%) with unruptured aneurysms. Of these nine patients, five were women and four were men (mean age, 62 yr; age range, 45-72 yr). Symptomatic aneurysms were located in the middle cerebral artery (n = 4), internal carotid artery (n = 3), posterior cerebral artery (n = 1), or vertebral artery (n = 1). The mean maximal diameter was 12.5 mm (range, 5-45 mm). Six patients underwent surgical treatment, of whom two experienced postoperative cerebral infarctions referable to the distribution of the artery harboring the aneurysm. Two patients were treated with aspirin, and one patient received no treatment. The mean follow-up period was 38 months (range, 1-60 mo). None of the patients experienced additional ischemic events during the follow-up period. Among the 41 previously reported patients, conservative treatment was used for 20 patients (mean follow-up period, 50.7 +/- 44.5 mo). Four of the 20 patients experienced recurrent TIAs, 1 patient experienced worsening of symptoms, and 1 patient died during the follow-up period. A total of 21 patients underwent surgical treatment (mean follow-up period, 33.6 +/- 32.3 mo). Of these patients, only one experienced recurrent TIAs. Two patients experienced postoperative seizures, and one patient died during the follow-up period. All recurrent symptoms with either surgical or conservative treatment were transient, and no patient experienced a major or disabling stroke during the follow-up period.

CONCLUSION

Ischemic events can occur distal to both small and large unruptured intracranial aneurysms (predominantly in the anterior circulation). The long-term risk of recurrent ischemic events, particularly major or disabling strokes, seems to be low with either surgical or conservative treatment.

Magnetic resonance imaging of embolism from intracranial aneurysms

Two patients with embolism from unruptured intracranial aneurysms are reported. These patients experienced cerebral ischemic attacks at the ages of 10 and 64 years, respectively. Angiography revealed normal extracranial vessels and middle cerebral artery aneurysms. Preoperative magnetic resonance imaging showed intraaneurysmal clots and cerebral infarcts distal to the aneurysms. Aneurysmal neck clipping was carried out on the young patient. In the other case, the aneurysmal sac was excised, the intraluminal clot was removed, and the neck was closed with nylon sutures. These are the first cases of embolism from unruptured aneurysms in which magnetic resonance imaging revealed intraaneurysmal clots and cerebral infarcts distal to the aneurysms.

Unruptured aneurysms in patients with transient ischemic attack or reversible ischemic neurological deficit. Report of eight cases

Thirty-five patients with unruptured aneurysms were treated between 1981 and 1987. Eight of them had either transient ischemic attacks or reversible ischemic neurological deficits as their presenting symptoms. Six of the eight patients underwent direct aneurysm surgery. All eight patients are well, and have had no recurrent attack during the follow-up period ranging from 2 to 7 years. The feasibility of surgical treatment for such aneurysms associated with reversible ischemic symptoms is discussed.

Pure motor hemiplegia secondary to a saccular basilar artery aneurysm

Pure motor hemiplegia is the most commonly encountered lacunar syndrome and is classically associated with small infarctions in the contralateral internal capsule or basis pontis. Pure motor hemiplegia has also been observed secondary to a wide variety of other vascular and nonvascular focal central nervous system processes. We describe a patient with pure motor hemiplegia associated with a saccular basilar artery aneurysm causing a lacunar infarction of the cerebral peduncle.

Neuropathological changes related to the transorbital application of ethyl 2-cyanoacrylate adhesive to the basal cerebral arteries of cats

The long-term toxic effects of ethyl 2-cyanoacrylate adhesive were evaluated histologically in 25 cats. Fresh medical- or commercial-grade adhesive was introduced transorbitally into the subarachnoid space in the vicinity of the right middle cerebral artery. Three sham-operated animals served as controls. The animals were sacrificed at intervals ranging from 2 days to 6 months. For both medical- and commercial-grade adhesive, neuropathological examination disclosed acute and chronic granulomatous inflammation of the meninges and evidence of severe vascular damage, including vessel wall necrosis, inflammation, thrombosis, and occasionally hemorrhage. Most animals showed cerebral infarcts of variable size in the territories of distribution of the basal arteries which were in contact with adhesive. The results of this study show that ethyl 2-cyanoacrylate is capable of producing severe arterial and parenchymal damage. The risk of its deleterious effects should be weighed against its potential benefits. Clinical experience would suggest that ethyl 2-cyanoacrylate can be used in difficult situations as long as care is taken to protect the brain and local blood vessels.

Platelet interaction within giant intracranial aneurysms

Turbulence within intracranial aneurysms may result in tearing of the aneurysmal wall, exposing the subendothelial matrix to circulating platelets. In this study, platelet interaction in giant intracranial aneurysms was evaluated by a dual-isotope technique employing In-labeled platelets and Tc-labeled red blood cells. The use of two isotopes allows the subtraction of the blood pool and the calculation of the ratio indium deposited:indium blood pool (In(D)/In(BP)). A ratio greater than zero indicates platelet deposition within aneurysm. Thirteen patients were evaluated in this way, with platelet deposition demonstrated in six. In these six patients, the ratio In(D)/In(BP) was found to be significantly elevated, with a mean value of 0.96 +/- 0.65. Three of these six patients has symptoms of recurrent transient neurological deficits; one of these three suffered a complete stroke following documentation of platelet deposition. In this case, the aneurysm was obtained at surgery and was found to contain intraluminal platelet aggregation when viewed by scanning electron microscopy. In the remaining seven patients, the ratio IN(D)/In(BP) was found not to be significantly elevated (mean -0.03 &/- 0.06), indicating the absence of active platelet deposition. Two of these patients had prior symptoms of cerebral ischemia; one of these was found to have an ulcer in the ipsilateral internal carotid artery which was probably responsible for thromboembolic events to the hemisphere. The authors conclude that platelet aggregation occurs more frequently than previously recognized in giant intracranial aneurysms, and their data substantiate the hypothesis that platelet metabolic products or thrombi originating from a large aneurysm may embolize to distal cerebral vessels.

Transient focal cerebral ischemia as a presenting manifestation of unruptured cerebral aneurysms

Few reports have described an association between cerebral transient ischemic attacks (TIAs) and unruptured cerebral aneurysms. This study presents seven patients with TIA who had aneurysms in a vascular distribution appropriate to their clinical symptoms. In three patients, angiographic evidence of embolization was present distal to the aneurysm without apparent cardiac or extracranial arterial source for the emboli. The most reasonable pathogenesis for TIA in a patient with an associated saccular aneurysm would be thrombosis of the aneurysmal sac with subsequent embolization. However, subarachnoid blood can cause permanent focal intracranial narrowing, and this appeared to be a factor in at least one patient. The results imply that patients with symptoms of TIA should have their intracranial arterial circulation visualized as part of the diagnostic evaluation.