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PubMed1996

Carotid endarterectomy. Lessons from intraoperative monitoring--a decade of experience.

OBJECTIVE: The authors analyzed a single institution's 10-year experience with intraoperative monitoring during 709 primary carotid endarterectomies and investigated the impact of contralateral internal carotid artery stenosis on carotid artery stump pressure (SP). SUMMARY BACKGROUND DATA: Stump pressure reflects the combination of contralateral carotid artery anatomy, collateral intracranial vasculature, and systemic blood pressure. By controlling for blood pressure with a stump index (SI) (SI = [SP/mean arterial pressure] x 100), a correlation between pressure and contralateral carotid artery anatomy can be demonstrated. Although the use of SP has long been advocated as an indicator of adequate cerebral perfusion, its correlation with perioperative complications while using an intraluminal shunt has not been evaluated completely. METHODS: From a series of 886 primary carotid endarterectomy cases, SP and mean arterial pressure were measured prospectively in 709 procedures. Temporary intraluminal shunts were used in cases with demonstrated contralateral carotid occlusion, prior cerebrovascular accident (CVA), or SPs less than 35 mmHg. Ipsilateral and contralateral angiographic degree of carotid stenosis was recorded at the time of the operation. Neurologic status was recorded prospectively for all 709 procedures. Operative electroencephalogram (EEG) changes and SP then were compared with the neurologic status of the patient in the perioperative period. RESULTS: The mean SP for the group (n = 709) was 46.7 +/- 15.3 mmHg (mean +/- standard deviation [SD]) with a mean SI of 54.9 +/- 22.6. The distribution for the SI is a more gaussian curve than that for SP. There were 19 ipsilateral CVAs (2.7%). The mean SP in the nonstroke group was 47.1 +/- 15.2 mmHg (mean SI = 54.7 +/- 16.5) compared with 31.9 +/- 13.2 mmHg (mean SI = 38.8 +/- 18.2) in the stroke group (P < 0.0001). Stroke rate for SP < or = 35 mmHg was 7% (13/185) versus 1.1% (6/524) for SP > 35 (p < 0.0001). Stump index and SP are related to contralateral carotid artery stenosis. The pattern of SI or SP versus contralateral stenosis is biphasic, with an increase at 75%. If SI is < or = 40, the mean contralateral stenosis is 55.1%; if SI is > 40, the mean contralateral stenosis is 35.1% (p < 0.05). Continuous EEG monitoring was completed for the 549 most recent operations. Patients who had a perioperative stroke had EEG changes observed during the procedure in only 6 of 12 cases (50% sensitivity), with 76% specificity. Using SP < or = 35 mmHg, sensitivity was 68% and specificity was 75%.

Aged↗
PubMed1998

Carotid endarterectomy by eversion technique: its safety and durability.

SUMMARY BACKGROUND DATA: The outcome of standard longitudinal carotid endarterectomy (CEA) can be measured by preservation of neurologic function with a low incidence of restenosis. Closure of the internal carotid arteriotomy with or without a patch may predispose to restenosis. Alternatively, transection of the internal carotid artery at the bulb with eversion endarterectomy allows expeditious removal of the plaque and direct visualization of the endpoint. Because the proximal internal carotid artery is anastomosed to the common carotid artery, this obviates the need for patch closure. The authors report their results with this technique in more than 2200 procedures. METHODS: From May 1993 to March 1998, 1855 patients underwent 2249 CEAs using the eversion technique. During the same period, 410 patients had 474 CEAs by standard technique. Three hundred fifteen procedures in the eversion group and 65 procedures in the standard group were combined CEA and coronary artery bypass grafts. Most solo CEAs (97%) were performed in awake patients using regional anesthesia. Shunts were used on demand in 6% of CEAs. RESULTS: The operative mortality rate was 1.02% (16/1575) in the solo eversion group and 2.2% (9/410) in the standard group. There were 18 permanent neurologic deficits (0.8%) in the eversion group and 11 (2.3%) in the standard group. Transient neurologic deficits occurred in 20 patients (0.9%) in the eversion group and 13 patients (2.7%) in the standard group. Of the 1855 patients, 1786 (96%) presented for duplex ultrasound follow-up. There were seven (0.3%) stenoses greater than 60% in the eversion group versus five (1.1%) in the standard group. CONCLUSIONS: Eversion CEA can be performed safely with a low rate of stroke and death and a minimal restenosis rate in short- and long-term follow-up.

Adult↗
PubMed2000

Carotid endarterectomy in the community hospital in patients age 80 and older.

OBJECTIVE: To determine whether the rates of death and complications of carotid endarterectomy (CE) were different in the octogenarian population than in patients younger than age 80. SUMMARY BACKGROUND DATA: The utility of CE depends on the ability of the surgeon and hospital to attain low rates of death and complications, including all subgroups of the patient population. In the past 30 years, the number of people age 85 and older has increased 274%. METHODS: Detailed chart review was carried out on all CE procedures done from 1979 through 1998. Descriptive demographic data, risk factors, surgical details, length of stay, deaths, and complications were recorded. RESULTS: A total of 2,398 CEs were performed in 1,970 patients; 2,180 procedures were performed in 1,783 patients younger than 80, and 218 CEs were performed in 187 patients age 80 and older. Sixty-five percent of the octogenarians and 67% of patients younger than age 80 had neurologic symptoms. Among asymptomatic patients, 89% had stenosis of 75% or more. There were 62 strokes in the 2,180 procedures in the younger group, for a stroke rate of 2.8%, and 7 strokes in the 218 procedures in the older group, for a stroke rate of 3.2%. The death rates were 0.9% for the octogenarians and 1.4% for the younger group. CONCLUSIONS: Carotid endarterectomy can be safely performed in a community hospital in patients age 80 and older. Outcomes in octogenarians were not significantly different than those of younger patients and were within the range required for CE to be considered beneficial in the prevention of stroke.

Age Factors↗
PubMed2000

A prospective randomized study on bilateral carotid endarterectomy: patching versus eversion.

OBJECTIVE: To compare the clinical outcome and restenosis incidence of patients who underwent carotid endarterectomy with patch closure (CEAP) on one side and carotid eversion endarterectomy (CEE) on the other. SUMMARY BACKGROUND DATA: Although a few investigators have compared the results of CEAP versus CEE, no reports have compared the outcome of CEAP versus CEE in the same patient. METHODS: Eighty-six patients were randomly selected for sequential surgical treatment involving either CEAP/CEE or CEE/CEAP. All patients underwent postoperative duplex ultrasound study and clinical follow-up at 1, 6, and 12 months and every year thereafter. Various factors were analyzed to ascertain any association with restenosis, and Kaplan-Meier analysis was used to estimate the risk of restenosis. RESULTS: Demographic and clinical data were similar in the CEAP and CEE groups. The selective shunting rate was statistically higher in the CEAP group. There were no perioperative deaths. Although the incidence of perioperative ipsilateral stroke was not significant, CEAP patients had a rate of combined transient ischemic attacks and strokes that approached statistical significance. The mean follow-up was 40 months. CEAP patients had a significantly higher incidence of restenosis and combined occlusive events and restenoses. Kaplan-Meier analysis showed that CEE had a significantly better cumulative patency rate than CEAP and that freedom from restenoses at 24 and 36 months was 87% and 83% for CEAP and 98% and 98% for CEE, respectively. CONCLUSIONS: CEE is less likely to cause perioperative neurologic complications and restenoses than CEAP. The significantly higher rate of unilateral recurrence suggests that local factors play a more important role than systemic factors in the occurrence of restenosis.

Adult↗
PubMed2000

Impact of race on the outcome of carotid endarterectomy: a population-based analysis of 9,842 recent elective procedures.

OBJECTIVE: To examine the influence of race and other potentially confounding variables on the outcome of carotid endarterectomy (CEA). SUMMARY: Previous studies have demonstrated that CEA is performed less frequently in black patients, although little attention has been focused on the influence of race on the outcome of surgery. METHODS: The Maryland Health Services Cost Review Commission database was reviewed to identify all elective CEA procedures performed in all nonfederal acute care hospitals in the state from 1990 through 1995 to examine the influence of race and other factors on the rates of in-hospital complications, in-hospital stroke, length of stay, and total hospital charges. RESULTS: Carotid endarterectomy was performed in 9,219 (94%) white and 623 (6%) black patients during this period. The in-hospital stroke rate was 1.7%-3. 1% among black patients and 1.6% among white patients. Black patients had a longer length of stay and higher mean hospital charges than white patients. Multivariate logistic regression analysis identified black race as an independent risk factor for in-hospital stroke. Performance of CEA by a high-volume surgeon was protective for the combined occurrence of in-hospital stroke or death, and whites were more than twice as likely to undergo surgery performed by high-volume surgeons. Conversely, undergoing surgery in a low-volume hospital was associated with in-hospital stroke, and blacks were four times as likely to use low-volume hospitals. CONCLUSIONS: Black patients who underwent elective CEA in Maryland from 1990 to 1995 had an increased incidence of in-hospital stroke, a longer hospital stay, and higher hospital charges than whites. Black race was identified as an independent risk factor for in-hospital stroke, although the reasons for this influence of race on outcome are undefined. The authors' observations also suggest the possibility of limited access to optimal surgical care among blacks, and this issue warrants further study.

Black or African American↗
PubMed2001

EEG evidence for shunt requirement during carotid endarterectomy: optimal EEG derivations with respect to frequency bands and anesthetic regimen.

Currently there is no consensus on the derivations that should be used for EEG monitoring during carotid endarterectomy (CEA). The aim of this study was to determine which derivations distinguish the best between patients requiring a shunt and patients who do not need a shunt. Four predefined frequency bands and two regimens for general anesthesia (isoflurane versus propofol) were used. EEG data (16 channels) were obtained from 152 EEGs recorded during carotid endarterectomy. Analog EEG signals of preclamp and clamp periods of 100 seconds were digitized to compute power spectra. Changes in power during clamping were calculated for all possible derivations in four predefined frequency bands and were expressed as Z-scores. For each derivation, the area under the receiver operating characteristics curve was calculated. Derivations with the greatest area under the receiver operating characteristics curve were considered to distinguish the best between the shunt and the nonshunt groups formed in retrospect on the basis of consensus between three independent and experienced board-certified electroencephalographers. The two different anesthetic regimens resulted in different patterns of EEG changes because of clamping. The optimal derivations to differentiate between the shunt and the nonshunt groups also differed for the two anesthetic regimens, although for both conditions, anterior head regions were especially preferred. The optimal derivations are given for each anesthetic regimen.

Adult↗
PubMed1999

Selection of patients for carotid endarterectomy: the role of ultrasound.

Stroke is the third leading cause of death in the western world and the major cause of disability among the middle aged and elderly populations. Carotid artery stenosis is the single most important risk factor for stroke. The North American Symptomatic Carotid Endarterectomy Trial and the European Carotid Surgery Trial have demonstrated that the risk of stroke is reduced by surgery in patients with high grade stenosis. Carotid plaque morphology also plays an important role; plaques which are ulcerated and echolucent are associated with a higher risk of stroke. Arteriography has long been regarded as the gold standard diagnostic tool for evaluation of carotid artery disease, but it is an invasive and costly technique which carries the risk of potentially serious complications. Doppler ultrasound can provide functional and anatomical information on vessel stenosis and plaque morphology at sub-millimetric resolutions and is an inexpensive and noninvasive tool. Color and spectral Doppler ultrasound are now recognized as the best screening tests for carotid artery stenosis. The evidence for its use as the sole diagnostic imaging modality prior to carotid endarterectomy is examined. The recent availability of ultrasound contrast agents helps to distinguish between pseudo- and true occlusions, improves ultrasound images and should help to reduce operator variability.

Blood Flow Velocity↗
PubMed2000

Antioxidant effect of oral dipyridamole during cerebral hypoperfusion with human carotid endarterectomy.

We sought to test the hypothesis of an antioxidant effect of dipyridamole in vivo in a model of cerebral hypoperfusion. Twenty-one patients (65+/-10 years, 11 men) undergoing carotid endarterectomy were allocated in two groups (group 1, 10 with dipyridamole, 200 mg p.o., 3-4 h before surgery; group II, 11 with placebo) in a double-blind placebo-controlled randomized design. Blood was sampled from ipsilateral jugular bulb, and plasma vitamin E content was assayed before, after 15 and 30 min of clamp, and 2 and 10 min after declamping. In 12 of them, lipoperoxides were assayed. Vitamin E plasma content decreased significantly in group II (rest, 3.71+/-0.22 mmol/mol of cholesterol, 100%) after clamp (91.5% of rest, p < 0.01) and remained unchanged during declamping (90.9% of rest, p < 0.01), but did not change in group I (rest, 3.5+/-0.44 mmol/mol of cholesterol, 100%) during clamping (99.9% of rest; p = NS) and after declamping (97.6% of rest; p = NS). Lipoperoxide concentration did not change in group I (rest, 302+/-8 a.u.; clamp, 296+/-13 a.u.; p = NS vs. rest; declamp, 304+/-8 a.u.; p = NS vs. rest), and increased significantly in group II (rest, 313+/-5 a.u.; clamp, 352+/-9 a.u.; p < 0.01 vs. rest; declamp, 343+/-6 a.u.; p < 0.05 vs. rest). Cerebral oxidative stress associated with human carotid endarterectomy can be attenuated by pretreatment with oral dipyridamole.

Aged↗
PubMed1991

Reversal of a dense, persistent, holohemispheric neurological deficit after an endarterectomy of the carotid artery: case report.

The role and timing of a carotid endarterectomy in the setting of an acute ischemic stroke-in-evolution remain controversial. Although computed tomographic (CT) scans typically show no abnormalities in the acute stage, it is generally agreed that a dense neurological deficit (hemiplegia) and/or multiple modality neurological disturbance (involving motor, sensory, gaze, and visual field impairment) represent contraindications to surgical intervention. We present a case of an acute right holohemispheric neurological deficit including dense hemiplegia, hemisensory loss, gaze disturbance, hemineglect, and impaired level of consciousness. This persisted for 4 days while serial CT scans showed no evidence of infarction. Angiography revealed pre-occlusive stenosis of the right internal carotid artery with sluggish antegrade flow. The anterior collaterals of the circle of Willis were impaired, and the right middle cerebral artery territory filled via the posterior communicating artery. Despite the dense neurological deficit persisting for 4 days, a carotid endarterectomy was performed. Gradual neurological improvement was noted within hours of the operation, and all neurological deficits resolved within the subsequent 3 days. This case is consistent with prolonged holohemispheric hemodynamic compromise below the threshold of neurological dysfunction, but above the threshold of tissue infarction ("idling neurons"). Features assisting in the recognition of this unusual scenario and the indications and risks of revascularization in this setting are discussed.

Aged↗
PubMed1998

The differences in electroencephalographic changes in patients undergoing carotid endarterectomies while under local versus general anesthesia.

OBJECTIVE: This study compared the electroencephalographic (EEG) changes occurring during carotid occlusion in 225 consecutive patients undergoing carotid endarterectomies performed by two surgeons, one using local and the other using general anesthesia. METHODS: A retrospective review of patients undergoing carotid endarterectomies for carotid occlusive disease was conducted. EEG changes associated with intraoperative ischemia (decreased amplitude, generalized slowing, and loss of fast activity) resulting in the need for an indwelling arterial shunt were recorded for the two anesthesia groups. To determine the similarities or differences between the two groups, the groups were compared regarding age, risk factors, and indications for surgery. RESULTS: Significant EEG changes were noted in 6 of 96 patients (6.3%) in the local anesthesia group versus 19 of 121 patients (15.7%) in the general anesthesia group. EEG changes consisted solely of generalized slowing in the local anesthesia group, whereas a more varied spectrum was observed in the general anesthesia group. The two groups were similar regarding age and risk factors. Although the local anesthesia group had more asymptomatic patients, symptomatic patients did not have a greater incidence of EEG changes. CONCLUSION: There is a large difference in EEG changes potentially requiring shunt placement in patients undergoing surgery while under local (6.3%) versus general (15.7%) anesthesia. This could not be explained based on age, risk factors, interpretation of EEG findings, or indications between the two groups. We conclude that EEG monitoring may be insensitive and may fail to detect ischemia in patients who are under regional anesthesia. Alternately, the presence of general anesthetics may alter the character of the EEG findings and increase the sensitivity of EEG monitoring to ischemic events.

Anesthesia, General↗
PubMed1999

Treatment of carotid tandem stenosis by combined carotid endarterectomy and balloon angioplasty: technical case report.

OBJECTIVE AND IMPORTANCE: Cervical internal carotid artery disease associated with high-grade carotid siphon stenosis poses a therapeutic challenge. This report describes the combination therapy of carotid end-arterectomy and intraoperative transluminal balloon angioplasty of the carotid siphon. CLINICAL PRESENTATION: A 67-year-old man sustained repeated left hemispheric and retinal transient ischemic attacks. Results of a diagnostic examination, including angiography, disclosed a 70% ulcerative stenosis of the left extracranial internal carotid artery as well as a 90% stenosis of the left intracavernous carotid artery. The decision was made for combined open and endovascular therapy. INTERVENTION: After standard endarterectomy, an introducer for the dilation catheter was placed into the common carotid artery before final closure of the arteriotomy and recirculation. Under intraoperative fluoroscopy, a 3-mm dilation balloon was navigated into the carotid siphon stenosis and inflated several times. A 30% residual stenosis in the carotid siphon was obtained as a final result. The intervention was completed without complications. No further neurological symptoms were observed during the follow-up period of 30 months. CONCLUSION: Carotid endarterectomy, combined with intraoperative transluminal angioplasty of carotid siphon stenosis, is a feasible procedure for selected patients with carotid tandem stenosis.

Aged↗
PubMed2001

Treating stroke as a medical emergency: a survey of resident physicians' attitudes toward "brain attack" and carotid endarterectomy.

OBJECTIVE: A major impetus of the "brain attack" campaign is the early recognition and treatment of acute stroke. Critical to this goal is the education of physicians during their residency training. METHODS: Resident physicians in Los Angeles who were in family practice (18%), internal medicine (51%), emergency medicine (20%), and neurology (11%) and had already completed their first year of training responded to a questionnaire on stroke and the treatment of carotid stenosis. RESULTS: Of the 266 respondents, 76% had heard of the "brain attack" campaign, 22% did not identify dysarthria as a symptom of stroke, and 21% did not identify obtundation as a presentation of stroke. Twenty-eight percent chose not to use tissue plasminogen activator for acute ischemic stroke, and 60% recognized the need to begin treatment within 3 hours. More than 90% of respondents were able to identify correct screening tests for patients with suspected carotid stenosis. However, 56% responded that they would not advocate operating on patients with asymptomatic severe stenosis (>70%) until stenosis reached a critical value (85%). Conversely, 45% would recommend operative treatment for symptomatic patients who had less than 60% stenosis. Sixty-eight percent would refer patients to vascular surgeons, 14% to neurosurgeons, and 17% to both for carotid endarterectomy. CONCLUSION: Recognition of stroke as a medical emergency is improving. However, significant progress can still be made in the recognition of stroke symptoms. Primary care and neurology residents remain skeptical about carotid endarterectomy for asymptomatic patients, whereas there is enthusiasm for treating stroke survivors. Education by members of the surgical community could promote the aggressive treatment of asymptomatic patients to prevent stroke.

Attitude of Health Personnel↗
PubMed2001

Carotid endarterectomy: can we select surgical candidates at high risk for stroke and low risk for perioperative complications?

DESPITE EVIDENCE OF the efficacy of carotid endarterectomy from the large randomized multicenter trials completed in the 1990s, the physician who treats patients with carotid artery stenosis still is faced with a difficult management decision. More recently, subgroup analyses have been conducted of asymptomatic and symptomatic patients enrolled in these trials to identify clinical and radiological factors that increase the rates of morbidity and mortality associated with surgery, as well as those that increase the risk of stroke without surgery. Knowledge of these factors is important to recommend the best course of action for the individual patient. In this article, we summarize the conclusions of some of the subgroup analyses from the major carotid endarterectomy trials.

Carotid Stenosis↗
PubMed2003

Early carotid endarterectomy after ischemic stroke improves diffusion/perfusion mismatch on magnetic resonance imaging: report of two cases.

OBJECTIVE AND IMPORTANCE: The functional magnetic resonance imaging techniques of diffusion-weighted imaging and perfusion-weighted imaging allow for ultra-early detection of brain infarction and concomitant identification of blood flow abnormalities in surrounding regions, which may represent brain "at risk." CLINICAL PRESENTATION: We report two patients with acute ischemic stroke associated with ipsilateral high-grade carotid stenosis. The first patient, a 64-year-old woman with a remote history of ischemic stroke and a vertebral artery aneurysm, presented with worsening of her preexisting right hemiparesis. The second patient, another 64-year-old woman with known multiple intracranial aneurysms and bilateral high-grade internal carotid artery stenosis, was admitted for the elective microsurgical clipping of an enlarging giant left carotid-ophthalmic artery aneurysm. Postoperatively, she developed right hemiparesis and mild aphasia. Both patients showed progressive worsening of their neurological deficits in the setting of small or undetected diffusion-weighted imaging abnormalities and large perfusion-weighted imaging defects. INTERVENTION: After prompt carotid endarterectomy, symptoms in both patients resolved or improved. Follow-up magnetic resonance imaging scans demonstrated resolution or significant improvement in the perfusion abnormalities in both patients. CONCLUSION: Carotid endarterectomy in the setting of diffusion-weighted/perfusion-weighted imaging mismatch can lead to improvement in cerebral perfusion as evidenced by resolution of the perfusion-weighted imaging lesion. Diffusion/perfusion magnetic resonance imaging may be useful in identifying patients with severe neurological deficits but without large territories of infarction who may safely undergo early surgical revascularization.

Brain↗
PubMed1979

Correlation of intraoperative electroencephalography with neurologic deficit after carotid endarterectomy.

In an attempt to prevent morbidity and mortality in carotid endarterectomy, we monitored 47 operations with intraoperative EEG to determine which patients should have a shunt during endarterectomy. The EEG was recorded for up to five minutes during test carotid cross-clamping. When EEG asymmetry between the cerebral hemispheres occurred, the clamp was immediately removed. A shunt was used in all patients who had EEG asymmetry. In the absence of EEG asymmetry, no shunt was used. Of the 38 patients with no EEG asymmetry intraoperatively, one patient had transient deficits postoperatively. Electroencephalographic asymmetry occurred in nine patients during test carotid cross-clamping. Postoperatively, five of these shunted patients awakened neurologically intact and four patients had transient deficit. When the EEG was normal and no shunt was used, patients did well; when the EEG was abnormal and a shunt was used, there was a high incidence of transient neurologic deficit.

Aged↗
PubMed1988

Learning curve for carotid endarterectomy.

It is generally accepted that training and experience are necessary to obtain acceptably low perioperative mortality and permanent neurologic morbidity for carotid endarterectomy. To test this hypothesis I analyzed the results of 600 consecutive primary carotid endarterectomies that I performed over a 13-year period beginning with my senior residency. The overall hospital mortality was 9/600 (1.5%), the permanent neurologic morbidity 11/600 (1.8%), and the combined mortality and permanent neurologic morbidity 20/600 (3.3%). The mortality for the first 300 operations was 6/300 (2%) (4/6 from stroke) and for the last 300, 3/300 (1%) (3/3 cardiac). All 11 nonfatal strokes occurred in the first 300 operations. Morbidity and mortality decreased with both cumulative experience and the number of operations done per year. While it is difficult to separate the effect of these two factors, the results suggest that both may be important in obtaining a combined perioperative mortality and permanent neurologic deficit below 3%.

Arteriosclerosis↗
PubMed1988

Cranial nerve injuries after carotid artery endarterectomy.

We present a seven-year experience with cranial nerve injuries due to carotid artery endarterectomy. A total of 433 carotid endarterectomies were done on 355 patients by senior surgical residents, with a staff surgeon assisting. Thirteen cranial nerve injuries were identified, five of which were permanent. Knowledge of the anatomic features of the cranial nerves and their branches in the operative field, as well as technical maneuvers during surgery, can reduce such injuries to a minimum.

Carotid Arteries↗
PubMed1995

Electrophysiological monitoring for selective shunting during carotid endarterectomy.

Selective shunt during carotid endarterectomy is more and more widespread, but it requires a monitoring system able to identify severe brain ischemia correctly. In 255 endarterectomies for severe carotid stenosis, we evaluated cerebral activity by means of sequential use of computerized two-channel electroencephalogram (EEG) and somatosensory evoked potentials (SSEPs). In 1.96% of cases, we observed changes referable to severe cerebral ischemia: in one case, in spite of shunting, EEG asymmetry persisted till the end of the operation, and the patient awoke with irreversible aphasia. In two other cases, a progressive disappearance of the cortical wave (N20) occurred in spite of a normal EEG pattern. None of the unshunted patients had postoperative deficit. Computerized EEG is an easily interpretable method of monitoring and reveals rapidly developing cerebral ischemia, but severe SSEP changes can occur in spite of a normal EEG pattern when cerebral ischemia has a slow onset. Although SSEP monitoring is a slower method of recording, it can give a finer distinction of less severe cerebral ischemia.

Adult↗