摘要:

&NA;An original stereotactic radiosurgical approach couplinga)Talairach's stereotactic methodology,b)a specially devised mechanical system, andc)a linear accelerator is detailed. The authors present their preliminary results on 66 patients with nonsurgical intracranial arteriovenous malformations. The doses delivered for treatment varied from 20 to 70 Gy. Doses of no more than 40 Gy were used in 80% of patients. An angiographic study was performed when the computed tomographic scan controls showed relevant modifications of the lesion volume. Total obliteration was obtained in 27 of the 41 patients (65.8%) who were followed up for at least 24 months. The percentage of the cured patients is significantly higher whena)the entire malformation is included in the 75% isodose (96%) andb)the maximum diameter of the lesion is less than 12 mm (81%). Two patients died of rebleeding at 18 and 29 months after treatment. (Neurosurgery24:311‐321, 1989)

ISSN:0148-396X    

出版商:OVID    

年代:1989

数据来源: OVID

摘要:

&NA;The excision of an arteriovenous malformation (AVM) located within eloquent neocortex presents a formidable neurosurgical challenge. Compromise of the vascular supply to normal surrounding brain or surgical trauma to essential neighboring neocortex may result in unacceptable postoperative neurological morbidity. In addition, successful removal of these lesions without the benefit of intraoperative corticography may leave in situ areas of highly epileptogenic brain, resulting in continued epilepsy. In this report, we describe eight patients who underwent craniotomy and excision of AVMs at our institutions. Six of these lesions were located in the dominant (left) hemisphere, and two were on the right. All patients underwent preoperative testing with Amytal administered via the carotid artery (Wada test). Subsequently, the patient was placed under local anesthesia, and we performed a craniotomy. Electrocorticography was used to identify epileptogenic brain in the region of the AVM and to establish after‐discharge thresholds to electrical stimulation. Stimulation‐mapping techniques were then used to delineate critical motor, sensory, and language areas. Trial occlusion of feeding vessels was also carried out to document postocclusion neurological deterioration, if any. At a later time, a second procedure was performed under general anesthesia to excise the lesion and any epileptogenic foci, using the cortical maps derived earlier. Using these techniques, it was possible to effect complete excision of these lesions in seven of eight patients without causing additional neurological deficits. (Neurosurgery24:322‐327, 1989)

ISSN:0148-396X    

出版商:OVID    

年代:1989

数据来源: OVID

摘要:

&NA;The acute effect of Nd:YAG laser beam on cerebral arteriovenous malformations (AVMs) was examined. Histological examination of the specimens after treatment with the Nd:YAG laser revealed that the most prominent effect of the laser was shrinkage of the collagen of the vessels of the AVM, which led to laser‐induced narrowing of blood vessels. The brain tissue confined to the resected AVM did not contain any histological evidence of acute damage. The resection of 10 cases of AVMs was safely accomplished with no morbidity or increased neurological deficits attributable to the laser technique. (Neurosurgery24:328‐333, 1989)

ISSN:0148-396X    

出版商:OVID    

年代:1989

数据来源: OVID

摘要:

&NA;The objective of the study was to review our recent experience with carotid endarterectomy performed within 30 days of completed cerebral infarction and to evaluate the role of computed tomographic (CT) scanning in the decisionmaking process. Twenty‐seven of 302 operations (9%) were carried out during the 30‐day time period. The mean interval between cerebral infarction and surgery was 14 days. Angiography revealed severe stenosis (>75%) of the internal carotid artery in 19 patients. Severe stenosis with deep ulceration found in 6 patients and moderate stenosis (i.e., 50‐75%) with deep ulceration was found in 2 patients. CT scans showed recent infarction in 4 patients and an old subcortical lacune in 2 patients. Twenty‐two patients were neurologically stable with mild deficits and showed normal results on a CT scan performed 24 hours or more after the ischemic event. These patients underwent early cerebral angiography and carotid endarterectomy without permanent morbidity or mortality. Two patients with moderate stable neurological deficits and findings of recent infarction on CT scans had uneventful postoperative courses. Five patients who were neurologically unstable underwent surgery. The 2 patients with repeated transient ischemic attacks and normal findings on CT scans had uneventful postoperative courses. Two of the three patients with progressive neurological deficits and CT findings of recent cerebral infarction experienced extension of their infarcts after surgery. One of these patients died. Our personal experience, together with a review of previous reports, indicated that patients who have minimal residual neurological deficits and whose CT scans show normal findings are at low surgical risk, perhaps approaching that of patients with transient ischemic attacks. The surgical risk is high in patients with progressive neurological deficits and CT scan findings of recent cerebral infarction. Patients with moderate, stable neurological deficits and CT scan findings of recent cerebral infarction appear to carry an intermediate surgical risk. (Neurosurgery24:334‐338, 1989)

ISSN:0148-396X    

出版商:OVID    

年代:1989

数据来源: OVID

摘要:

&NA;The reliability of selective shunting based on computerized electroencephalographic (EEG) monitoring has not been addressed. In this study, 103 carotid endarterectomies were performed with selective shunting based on a two‐channel computerized EEG monitor that processed the on‐line, raw electroencephalogram (EEG) to produce a compressed spectral array (CSA). Ischemic EEG events were identified by amplitude attenuation of the raw EEG and/or loss of high‐frequency activity on the CSA. Fourteen patients (13.6%) received a bypass shunt, and postoperative neurological examinations showed 97 patients (94.2%) to be intact. A correlation between total (cumulative) ischemic EEG time and the postoperative neurological exam was demonstrated (P< 0.0001). Six postoperative deficits (5.8%) occurred, five in patients whose computerized EEGs demonstrated an ischemic EEG event late during carotid clamping, when it was no longer possible to place a shunt. The sixth deficit was found in a patient whose EEG did not demonstrate any signs of cerebral ischemia. Five of these six new deficits resolved within 12 hours, and only one persisted for 72 hours, when the patient died of a pulmonary embolism (cerebral infarction and mortality rate of 1%). These results appear to demonstrate that two‐channel monitoring of both the CSA and the unprocessed (raw) EEG simultaneously can be used as a reliable indicator of whether a bypass shunt is required during carotid cross‐clamping in all patients, regardless of their preoperative neurological history or angiographic findings. (Neurosurgery24:339‐344, 1989)

ISSN:0148-396X    

出版商:OVID    

年代:1989

数据来源: OVID

摘要:

&NA;Seventeen head‐injured patients with signs of brain stem compression at admission underwent emergency bilateral burrhole exploration before computerized tomographic (CT) scanning. After exploration of the epidural and subdural spaces, real‐time ultrasonography was performed intraoperatively to identify intraaxial hematomas. Epidural or subdural hematomas were identified surgically in 11 patients (65%) and immediately evacuated through a craniotomy; in 2 patients, bilateral subdural hematomas were removed. Ultrasonography showed no evidence of intracerebral mass lesions in 14 (82%) of the 17 patients, demonstrated extensive contusions of the temporal lobe in 2 patients (prompting partial lobectomy in both cases), and revealed a small intraparenchymal hematoma deep within the dominant hemisphere, which was not removed, in 1 patient. The sensitivity of ultrasound images for identifying intraparenchymal lesions was evaluated postoperatively by CT or autopsy. In 15 patients (88%), the results of ultrasonography were confirmed. In 2 (12%), CT scans showed small but significant lesions at the frontal pole missed by ultrasonography; one patient had a residual subdural hematoma, and the other a small intraparenchymal hemorrhage. These results confirm that patients with clinical evidence of brain stem compression soon after head injury often have extraaxial hematomas that can be readily identified by burr‐hole exploration. Although intraparenchymal hematomas are rare immediately after head injury, they can ususally be identified by intraoperative ultrasonography. This simple technique can reduce the risk of missing intractranial hematomas during emergency burr‐hole exploration and improve intraoperative decision making in this population of severely head‐injured patients. (Neurosurgery24:345‐347, 1989)

ISSN:0148-396X    

出版商:OVID    

年代:1989

数据来源: OVID

摘要:

&NA;Intracranial pressure (ICP) is often measured from intraventricular catheters, a technique that allows therapeutic drainage of ventricular cerebrospinal fluid (CSF) as an aid in controlling ICP and circumventing obstruction. Drainage of CSF simultaneously with ongoing ICP measurement has been advocated as safe and efficient, and devices are commercially available to permit this practice; however, this concept has been seriously challenged, based on clinical observations. The inaccuracy induced by simultaneous CSF drainage and ICP monitoring is quantitated in this report in a mechanical brain model using a standard ventricular catheter. The following conclusions have been confirmed: 1) rapid CSF drainage induces a severe artifactual reduction in measured ICP, more extreme at higher pressures; 2) calibrated slower rates of CSF drainage produce a severe, although less immediate, reduction in measured ICP; 3) severe artifact appears even in the presence of continuous CSF outflow, so a system that measures ICP only in the presence of CSF flow does not prevent artifact; 4) with simultaneous CSF drainage, measured ICP is determined more by the outflow pressure setting than by actual brain pressure; 5) Since ICP elevation of 25 to 30 mm Hg blocks CSF production, even slow fluid drainage at high pressures should ultimately lead to ventricular collapse and severe artifact. (Neurosurgery24:348‐354, 1989)

ISSN:0148-396X    

出版商:OVID    

年代:1989

数据来源: OVID

摘要:

&NA;In an effort to determine the value of tissue‐type plasminogen activator (TPA) in the treatment of embolic stroke, 17 rabbits were subjected to a model of embolic stroke in which 2‐hour‐old, tin‐impregnated, autologous clots were embolized to the bifurcation of the internal carotid artery at the circle of Willis via retrograde injection into the cannulated external carotid artery. High‐resolution digital subtraction radiography was used to localize clots intracranially at the carotid bifurcation. Circulation through the internal carotid artery and intracranial vessels was monitored with serial digital subtraction angiography before and after embolization and during treatment. Disappearance of the tin marker on the digital subtraction radiograph indicated dissolution of clot and was associated with reestablishment of circulation on the digital subtration angiogram. Experimental animals were treated with human‐specific recombinant TPA 30 minutes, 2 hours, or 4 hours after clot embolization. TPA was administered as an intravenous bolus of 0.5 mg/kg followed by an infusion of 1 mg/kg/h for 2 hours. Digital subtraction angiograms were performed every 30 minutes. All clots dissolved, and cerebral circulation was reestablished within 120 minutes of treatment. In control animals treated with saline, embolized clots were stable, and the internal carotid artery remained occluded. At the completion of each study, the animal was perfused with freshly prepared, buffered 2,3,5‐triphenyltetrazolium chloride (TTC) for demarcation of cerebral infarction. Control animals demonstrated infarction of 50 ± 3.6% of the ipsilateral cerebral hemisphere, with an infarct weight of 2.1 ± 0.2 g. The weight of cerebral infarction, as defined by the failure of tissue to stain with TTC, was reduced significantly in TPA‐treated animals (P< 0.01). Treatment begun 30 minutes after clot embolization resulted in the most pronounced reduction in cerebral infarction. No intracerebral bleeding was observed. Results indicate that treatment with TPA is effective in dissolving embolic clots and reestablishing intracranial circulation. For best protection against cerebral infarction, however, treatment should be started as soon as possible. (Neurosurgery24:355‐360, 1989)

ISSN:0148-396X    

出版商:OVID    

年代:1989

数据来源: OVID

摘要:

&NA;In this prospective study, 100 patients with subarachnoid haemorrhage (SAH) were assessed at discharge, 3 months, and 1 year using modern methods of neuropsychology to examine cognitive status and semistructured interviews to assess changes in personality and quality of life. A control group of 50 patients suffering myocardial infarction were also assessed at discharge and 1 year. Results of cognitive testing in the SAH group were unremarkable and compared well with the control group. Similarly, there was no evidence of a consequent reduction in the quality of life in the majority of the SAH patients. These results lead us to conclude that where the medical and surgical course of SAH is uncomplicated, patients recover with no permanent or significant reduction in their intellectual ability of life status. Possible reasons for the difference between these results and those of other studies are discussed. (Neurosurgery24:361‐367, 1989)

ISSN:0148-396X    

出版商:OVID    

年代:1989

数据来源: OVID

摘要:

&NA;In patients with subarachnoid hemorrhage, delayed neurological deficits, often followed by infarction, are believed to result from ischemia caused by vasospasm. Cerebral blood flow (CBF) data have been useful in predicting the risk of vasospasm in these patients and in distinguishing those deficits caused by vasospasm. Although CBF thresholds for infarction have been established in animals, few clinical studies have correlated CBF values with neurological symptoms and infarction. To assess the sensitivity to ischemia provided by xenon‐enhanced computed tomography (Xe/CT) of CBF and to define the clinical significance of specific values that it measures, we compared the clinical, CT, and Xe/CT findings on CBF in 51 patients with subarachnoid hemorrhage caused by ruptured aneurysms. Each patient had 1 to 6 Xe/CT studies. Fourteen patients had symptomatic vasospasm. In all 14, the first post deficit Xe/CT study found abruptly reduced CBF, either regionally or globally. In 9 of these 14 patients, flow values fell below 15 ml/100 g/min in 2 or more adjacent 2‐cm cortical regions of interest, and in all 9, concurrent follow‐up CT scans showed infarction in these regions. Eight of the 9 had paralysis and a severe sensory deficit. No patient whose CBF remained above 18 ml/100 g/min developed infarction. The blood flow studies caused neither significant complications nor neurological deterioration. The Xe/CT CBF method appears very sensitive to the early detection of symptomatic vasospasm. In most patients with subarachnoid hemorrhage, this noninvasive technique can replace angiography to delineate the location and severity of vasospasm, and may be useful in predicting the development of infarction. (Neurosurgery24:368‐372, 1989)

ISSN:0148-396X    

出版商:OVID    

年代:1989

数据来源: OVID