Decision of Shunt Insertion Based on Electroencephalography and Stump Pressure During Carotid Endarterectomy

BACKGROUND: Carotid endarterectomy (CEA) is an effective treatment for the prevention of stroke in patients with high grade carotid stenosis. Electroencephalographic (EEG) monitoring and measurement of stump pressure are the most widely used methods for assessing the risk of cerebral ischemia during CEA. We designed this study to assess the usefulness of EEG and stump pressure for shunt insertion during CEA. METHODS: Nineteen patients were enrolled from January, 1996 to April, 1999. We calculated the percent of carotid stenosis in the patients by the NASCET (North American Symptomatic Carotid Endarterectomy Trial) criteria. The inclusion criteria of the CEA were high grade stenosis (>70%), or moderate stenosis (>50%) with ulcerated plaque. Intra-operative monitoring by using stump pres-sure, and an EEG was performed in 19 operations. RESULTS: The number of patients with asymptomatic and sympto-matic carotid stenosis were 6 and 13 respectively. Shunt during the operations was used in 12 patients; nine had both significant EEG changes and low stump pressures, two had only low stump pressure, one patient had only a significant EEG change. The peri-operative complications of mortality and stroke were found in one case. In the other patients, there no stroke recurrences during the mean follow-up period of 24 months. CONCLUSIONS: EEG and stump pressure may be useful in deciding shunt insertion during CEA for detecting ischemic changes.

The Diagnostic Values of Neurological Examination and Labratory Studies in the Patients of Myelopahty

Though diagnosis of myelopathy can be easily made by history and neurological examination, modern technologies, such as MRI and evoked potential study (EPS), have played an important role in making the anatomical and pathological diagnosis of myelopathy. To assess the accuracy of clinical diagnosis and the role of the laboratory studies, we prospectively studied 26 patients with myelopathy, admitted to S.N.U.H. We tried to decide, by clinical history and examination, the anatomical location and the pathological diagnosis, and compared them with final diagnosis. 1. The final diagnosis could be made in 23 out of 26 patients. 2. Of 17 patients with the initial clinical diagnosis of intramedullary lesion (IML), two patients turned out to have extramedullary lesions (EML). Final diagnosis could not be made in three patients, and imaging studies and EPS didn't reveal definite local lesions. In another group of nine patients with the initial clinical diagnosis of EML, three patients had IML. 3. The clinically suspected levels of lesions were shown to be accurate within one level in 20 out of 26 patients after MRI. 4. Clinical diagnosis was accurate in 18 out of 26 patients. 5. Among the laboratory tests, MRI helped localize the lesions and make the final diagnosis. EPS was most helpful in making a diagnosis of multiple sclerosis by finding out asymptomatic second lesions. Even with thorough work-up the etiologies of myelopathy in three patients could not be elucidated. 6. Review of wrong diagnosis showed that diagnostic errors were attributed to incomplete history taking or examination, misinterpretation of clinical data, and unusual presentations or unsuspected rare diseases. Therefore, the authors conclude that the physician's clinical examinations in the diagnosis of neurologic diseases are still valuable despite the technology of the laboratory studies is developing further in present days.