摘要:

&NA;Transcranial Doppler (TCD) was used to assess collateral flow and to quantitate perfusion velocity changes in a group of 18 patients requiring temporary or permanent surgical occlusion of the internal carotid artery for treatment of their cerebrovascular lesions. Velocity measurements were correlated with times of occlusion and neurological outcome in order to assess safe vessel occlusion times and the need for an intraoperative shunt. These data were used to calculate a perfusion velocity index (PVi), which indicated that values >2 were well tolerated, and values of <1 were associated with ischemic signs. In addition, preoperative TCD examinations were combined with compressive maneuvers of the carotid artery in the neck to evaluate the feasibility of carotid clamp ligation for the treatment of giant intracranial aneurysms deemed unsuitable for direct clipping. When maintenance of neurological function and intracranial vessel flow velocities were found to be normal, with aneurysmal flow velocities of zero, ligation of the carotid artery could safely be undertaken. Finally, TCD allowed continuous surveillance of cerebral hemodynamics, which gave immediate assurance of postoperative ICA patency, as well as the ability to identify high velocity states associated with hyperperfusion syndromes, which occurred in two patients. (Neurosurgery25:383‐389, 1989)

ISSN:0148-396X    

出版商:OVID    

年代:1989

数据来源: OVID

摘要:

&NA;Twenty patients who underwent early aneurysm surgery—that is, surgery within 72 hours after rupture—underwent further follow‐up examination including magnetic resonance imaging (MRI) of the brain and a comprehensive neuropsychological assessment. Significant statistical correlation between tissue loss as seen on a late MRI scan and neurobehavioral deficits could not be established. Among 9 patients with no tissue loss seen on MRI, 3 exhibited substantial cognitive dysfunction and 6 had mild impairment. Three patients showed minor but corresponding tissue loss and deficits. In 3 patients with pronounced pathological indications on MRI, evidence of cognitive dysfunction was absent in 2, and 1 patient showed substantial impairment. The remaining 5 individuals displayed moderate pathological indications on MRI, with no obvious correspondence to cognitive functioning. In 7 patients, small white matter lesions, probably silent infarcts not seen on computed tomographic scan, were discovered on MRI. There was a clear relationship between arterial hypertension prior to aneurysm rupture and the extent of tissue loss seen on MRI. Absence of pathological findings on MRI scan did not exclude cognitive malfunctioning, and vice‐versa. (Neurosurgery25:390‐397, 1989)

ISSN:0148-396X    

出版商:OVID    

年代:1989

数据来源: OVID

摘要:

&NA;We review our recent experience with occlusion of the cervical internal carotid artery (ICA) in 15 patients with symptomatic aneurysms of the cavernous segment. All the patients were women and ranged in age from 38 to 74 years. Ten patients sought treatment initially for ophthalmoplegia, 9 for retro‐orbital pain, 8 for facial paresthesia, and 3 for loss of vision. Two patients had symptoms of transient ocular or brain ischemia. The diameter of the aneurysm was greater than 3 cm in 10 patients. Ten patients underwent gradual occlusion of the ICA by Selverstone clamp under anticoagulation and monitoring of neurological status. One patient underwent ligation of a severely stenotic ICA under general anesthesia and electroencephalographic monitoring. Four patients underwent trapping of the aneurysm (after attempts at direct obliteration) under electroencephalographic and cerebral blood flow monitoring. Two patients with incompetent circle of Willis collaterals underwent prophylactic superficial temporal artery to middle cerebral artery bypass surgery prior to ICA occlusion. There was no postoperative clinical change in 9 patients. Ophthalmoplegia improved in 2 patients, and facial pain improved in 3. Three patients developed new extraocular muscle palsies within hours of ICA occlusion; these resolved in all patients by 1 week postoperatively. No change in aneurysm size was documented by serial postoperative computed tomographic or magnetic resonance imaging scans. After a follow‐up of 5 to 6 years (range, 6 months‐9 years), 11 patients have remained neurologically stable. Two patients experienced delayed transient worsening of visual or facial symptoms. Two patients developed delayed ipsilateral brain ischemia: one patient had a visibly patent superficial temporal artery to middle cerebral artery bypass; the second patient had an occluded A‐1 segment that previously had been patent. These results are discussed in light of direct approaches and recent techniques of intervention. (Neurosurgery25:398‐404, 1989)

ISSN:0148-396X    

出版商:OVID    

年代:1989

数据来源: OVID

摘要:

&NA;We have developed a noninvasive method to determine the flow rates necessary to produce hyperosmotic blood‐brain barrier disruption in individual animals. The method uses the intracarotid infusion of 0.9% NaCl at increasing flow rates, while concurrently measuring the amplitude of the somatosensory evoked potential (SSEP). For these studies, dogs were prepared with craniotomies to visualize the duration of cortical blanching. Saline (0.9% NaCl) was infused into the internal carotid artery at flow rates of 0.9 to 2.1 ml/s for periods from 2 to 40 seconds while the SSEP was concurrently measured in six 30‐second epochs before, during, and after the infusion. There was a linear relationship between the duration of cortical blanching (from 2 to 30 seconds) and amplitude suppression of the major negative deflection of the SSEP. This relationship allowed us to predict the intracarotid infusion rate necessary to achieve cortical blanching for periods of 20 seconds or more. Subsequent infusion of 1.4 or 1.6 osmolar mannitol at the predicted flow rate resulted in more pronounced suppression of the SSEP than did 0.9% NaC1 and produced disruption of the blood‐brain barrier as documented by computed tomographic scans with contrast enhancement. Intracarotid infusions of 0.9% NaC1 that produced partial blanching (partial replacement of blood in cortical vessels) were associated with paradoxical enhancement of SSEP amplitude, thus providing an additional measure of the adequacy of the infusion rate. This technique provides a reliable method to determine intracarotid infusion rates for hyperosmotic disruption of the blood‐brain barrier in individual animals, before the intracrotid infusion of hyperosmolar solutions. (Neurosurgery25:405‐411, 1989)

ISSN:0148-396X    

出版商:OVID    

年代:1989

数据来源: OVID

摘要:

&NA;Cisternal puncture, although less frequently used since the advent of computed tomography and magnetic resonance imaging, is an important tool in the neurodiagnostic armamentarium. An anatomic study of cisternal puncture was conducted on fresh cadavers by direct visualization and fluoroscopic guidance of cisternal puncture. Anatomic and radiographic analyses demonstrated a dramatic dynamic anatomy of the cisternal space during cisternal puncture and indicated that “tenting” of the dura mater over the needle occurs reliably during cisternal puncture. Lateral fluoroscopy may decrease the risk of cisternal puncture by allowing visualization of needle depth in the cisternal space. (Neurosurgery25:412‐415, 1989)

ISSN:0148-396X    

出版商:OVID    

年代:1989

数据来源: OVID

摘要:

&NA;Studies reporting the composition of cerebrospinal fluid obtained from hydrocephalic humans have been critically reviewed. Hydrocephalus‐induced alterations in the cerebrosinal fluid concentrations of neurotransmitters and peptide neuromodulators, products of glycolysis and nucleotide metabolism, neural cell‐derived proteins and enzymes, and serum‐derived proteins have been documented. The data are interpreted with reference to experimental studies. The reported changes suggest that in the hydrocephalic brain there are disturbances of oxidative metabolism and neurotransmission, and perhaps damage to periventricular cells particularly when intracranial pressure is elevated. Although no assays have provided and entirely useful guide to aid decisions regarding shunt therapy, they have provided in vivo information regarding the pathophysiology of hydrocephalus. (Neurosurgery25:416‐423, 1989)

ISSN:0148-396X    

出版商:OVID    

年代:1989

数据来源: OVID

摘要:

&NA;We used intracerebral transluminal angioplasty to treat two episodes of symptomatic vasospasm in a patient recovering from an aneurysmal subarachnoid hemorrhage. The procedures were performed after medical therapies, intravascular volume expansion, and induced arterial hypertension failed to alleviate the patient's neurological condition. The first angioplasty, confined to the right middle cerebral and distal internal carotid arteries, took place more than 30 hours after the onset of left hemiplegia. Despite the subsequent discovery of a small parietal lobe infarct, it brought about a marked improvement in left motor function and may have also limited the spread of necrotic damage. The second angioplasty was necessitated when stenotic segments of the basilar and posterior cerebral arteries caused a 24‐hour decline in the patient's mental status. Although delayed in relation to the onset of symptoms, it successfully reversed the patient's comatose state. The use of transluminal angioplasty for vasospasm is generally limited to cases where it can be performed shortly after the onset of neurological symptoms; delaying the procedure increases the risk of hemorrhage from reperfused areas of infarction. Our experience with this patient demonstrates that delayed angioplasty can improve vascular flow to ischemic territory, even after infarction, without complications and with resultant improvement in neurological function. (Neurosurgery25:424‐429, 1989)

ISSN:0148-396X    

出版商:OVID    

年代:1989

数据来源: OVID

摘要:

&NA;Three cases of large cerebral arteriovenous fistulae are presented in which surgical ablation was complicated by brain swelling from hyperperfusion breakthrough believed to be caused by acute intraoperative hypoperfusion superimposed on chronic preoperative hypoperfusion. On the basis of these cases, experimental data, and theoretical considerations, we seriously question the wisdom of using staged surgical resection of cerebral arteriovenous malformation to prevent complications related to alterations in cerebral hemodynamics. The reasons for this concern are: the repeated occurrence of acute‐on‐chronic hypoperfusion during staged resection; a lack of understanding of the time course for the correction of a disordered autoregulation; risk of hemorrhage between the initial and final resection; difficulty in assessing and substantiating flow reduction after subtotal resection; the rapidity of collateralization; the divergence of flow from large, readily accessible feeding arteries to deep penetrating vessels; and attenuation of the wall thickness in collateral vessels as a consequence of increased flow. (Neurosurgery25:429‐436, 1989)

ISSN:0148-396X    

出版商:OVID    

年代:1989

数据来源: OVID

摘要:

&NA;Two cases of petroclival meningiomas are reported wherein the tumors were completely destroyed without surgical resection or external‐beam irradiation by means of permanent stereotactic implantation of one or two high‐activity iodine‐125 seeds. (Neurosurgery25:436‐442, 1989)

ISSN:0148-396X    

出版商:OVID    

年代:1989

数据来源: OVID

摘要:

&NA;A 30‐year‐old woman underwent surgical partial callosotomy (posterior half) for removal of an arteriovenous malformation. The patient submitted to neuropsychological evaluation before and after surgery for a period of 8 months. There was transient dysfunction attributable to disconnection of parietal, temporal, and occipital connections. Because the symptoms disappeared over time, we conclude that the transcallosal surgical approach can, in the long term, be considered a relatively harmless method. (Neurosurgery25:442‐447, 1989)

ISSN:0148-396X    

出版商:OVID    

年代:1989

数据来源: OVID