To achieve immediate control of a person undergoing a seizure, an early and effective antiepileptic drug (AED) therapy is required. In this regard, a monotherapy with a minimal dosage is always preferred, and as for the choice of drug, the main factor to consider is whether the drug's clinical effect is suited to the type of seizure or epilepsy manifested. Even so, several possible choices are usually available, often between drugs presenting only subtle differences with respect to their efficacy. This fact, combined with the need for long-term treatment, makes the drug's possible toxicity a key issue. Further, to some degree the choice of drug may also be influenced by personal opinion or previous experience. Given these considerations, drugs that can be efficacious for major types of seizures are herein described and discussed. Phenytoin (PHT), in contrast to most AEDs, follows a zero order kinetics or, in other wouds, a culvilinear relationship between the dose and the serum level. The curve breaks in the area of the therapeutic level, which means that even minor changes in the dosage may cause disproportionately large changes in the serum level, so that the amount of the daily PHT dose may require minor adjustment. Turning to another drug, carbamazepine (CBZ) induces its own metabolism (autoinduction) , so that unusually high levels of CBZ may be obtained for the first 1 or 2 weeks of treatment compared to those of chronic patients. Therefore when using CBZ, it is important to monitor the doses being provided to avoid acute toxicity. Valproate (VPA) is another drug to consider. When treating epileptic women of child bearing age, conven-tional formulations of valproate should be replaced with a controlled release VPA formulation because of the risk of malformations occurring in the newborn, since a correlation has been found between a high VPA serum level and newborn malformations. Failing to take the medication as prescribed is a major reason for poor seizure control, and methods to determine non-compliance are discussed. AEDs possess a great potential for interacting with each other and with other drugs. Therefore when prescribing other drugs to AED patients, it is important to make them aware of the risks of interactions. Complete seizure control should never be the sole goal. Problems to be considered are how the seizures ultimately affect the patient's quality of life and whether the prescribed AEDs will eliminate further seizures.

View full abstract

To determine the localization of the epileptic focus, noninvasive evaluation that includes an analysis of the seizure characteristics, repeat EEGs, and imaging diagnosis should first be performed. If these noninvasive studies are not helpful in determining the distribution of epileptogenic areas, then invasive intracranial EEG monitoring becomes necessary, and for this purpose three types of electrodes, depth, subdural, and epidural, have been used. In this regard, the subdural recording method has become the most widely employed method internationally. The use of surgery for treating intractable epilepsy can be divided into two types : resective surgery or disconnective surgery. Resective srugery includes lesionectomy, cortical excision, and lobectomy. Subpial resec-tion, which is used when performing cortical excision, was conceived by Horsely and still constitutes the basic technique in the surgical treatment of epilepsy. The use of temporal lobectomy was established during the 1950's, but now, a more selective resection of the mesial temporal structures, under the guidance of a surgical microscope, is empolyed. A Iateral temporal approach (anteromedial temporal lobectomy) is one of these temporal methods of surgery. This procedure has several advantages, which include an easy orientation of the anatomical structures and a minimal risk of postoperative neurological deficits, such as speech disturbance or visual field defects. Disconnective surgery involves corpus callosotomy, multiple subpial transection (MST), and/or functional hemispherectomy. The use of corpus callosotomy for cases of epilepsy began in 1940 and has proven very effective for the control of drop attacks. We describe the technical aspects of temporal lobectomy and corpus callosotomy in detail and provide illustrative drawings.

View full abstract

To clarify the hyperacute stage pathophysiology of a brain injury, microangiography of cerebral parenchymal blood vessels and measurement of cerebral blood flow (CBF) were undertaken after experimental brain injury was induced in rabbits. In this experimental study, the rabbits were anesthetized with pentobarbital, after which a focal brain injury of 100 gcm was produced by dropping a stainless steel cylinder onto the surface of the right frontpar-ietal lobe. Microangiography was performed after an intracarotid arterial injection of carbon black solution with gelatin under a pressure of 200 torr. Microangiograms of a rabbit group given a sham operation clearly showed the normal network of the parenchymal blood vessels. In contrast, in microangiograms taken 15 minutes after the injury, the network of the parenchymal blood vessels was less distinct and dilatation of perforated cortical arteries was seen in conjection with mild leakage of the carbon black. Thirty minutes after the injury, the number of dilated arteries and the extent of carbon black leakage from the cerebral parenchymal blood vessels had increased markedly, and at 24 hours after the injury, microangiograms no longer depicted the blood vessel networking but clearly showed a hematoma that had resulted from the brain injury. Further, the cerebral blood flow (CBF) , which was continually measured by laser Doppler flowmetry for one hour after the injury, initially showed an immediate decrease, and, at 15 minutes after the injury, the CBF was found to have dropped to 1/3 of its normal value and did not subsequently recover. The results of this experimental study have confirmed that functional changes do occur in the cerebral parenchymal blood vessels during the hyperacute stage of a brain injury, together with a significant decrease in the CBF value.

View full abstract

In a retrospective study of patients who underwent metastatic brain tumor surgery, we have evaluated the efficacy of intraoperative radiotherapy (IOR) for the preventlon of a local recurrence. This study consisted of 78 cases with a metastatic brain tumor that were surgically treated between 1986 to 1992. These cases were classified into three groups : patients who underwent surgery without radiotherapy (S : 36 cases), patients who underwent surgery and post-operative conventional radiotherapy (S+ R : 27 cases) , patients who underwent surgery with IOR (S+I0R : 15 cases) . Of the 78 cases, 77 involved a total resection, and the remaining case involved a subtotal resectlon. In the S+ R group, a total dose of 40-56.5 Gy (mean 45.6 Gy) was delivered by using a 10 MeV Iinear accelerator. In the S+ IOR group, a total dose of 20-25 Gy was delivered by using a betatoron. The IOR cone diameter was adjusted to include a 5 mm perimeter of normal brain tissue, and the 80% isodose line was set to penetrate 5-10 mm below the deepest aspect of the tumor. Our analysis revealed that the respective overall local relapsing-free rates for the S, S+R and S+I0R groups were : 46.2%, 88.0%, and 79.9% at 6 months : and 36.4%, 70.7%, and 79.9% at 12 months. For the lung cancer cases, the respective values were as follows : 37.5%, 82.6%, and 84.6% at 6 months ; 30.2%, 67.6%, and 84.6% at 12 months. Further, no significant differences were seen in local recurrence rates between the S+R and the S + IOR groups. The mean number of hospitalization days in all 3 groups were : 43.0 days, 75.9 days, and 37.4 days, respec-tively. Thus, the number of hospitalization days in the S+I0R group was half that of the S+R group. Based on these findings, it appears that IOR treatment resulted in as good localized tumor control as is achieved by conventional radiotherapy and that the number of days of hospitalization is shortened. These findings thus confirm that IOR therapy contributes to improving the quality of life of mestastatic brain tumor patients.

View full abstract

It has been recognized that surgically-treated, even successfully clipped, intracranial aneurysms may regrow in time. In this study, the authors have tried to determine how many surgically treated aneurysms are likely to recur. Between 1969 and 1992 they have clipped 417 saccular aneurysms in 359 patients. After excluding 26 patients who soon died postoperatively, of the remaining 333 patients, 257 patients (77%) were followed up and retrospec-tive review of these patients has revealed that 83 patients underwent IV-DSA to determine whether they had an aneurysmal recurrence. The follow-up period for those patients was 8.8±5.3 years (1〜25 years) . Five of these follow up patients (1.9%) were known to have experienced rebleeding, based on their medical records or from a telephone interview. In one of these five patients, an aneurysmal recurrence was confirmed by cerebral angiography. With regard to the ramaining 4 patients, cerebral angiography revealed 6 newly developed aneurysms. As a result of the postoperative IV-DSA study of 83 patients, 2 cases were diagnosed as having had an aneurysmal recurrence. An aneurysmal recurrence was seen proximal to the clip in one patient, and contralateral to the previous aneurysm in another patient. The reported incidence of an initial subarachnoid hemorrhage in the general population varies from 11 to 16/ 100,000 (population)/year. Based on our findings of a second subarachnoid hemorrhage in our surgically treated patients, we have roughly calculated the incidence of a recurrent subarachnoid hemorrhage to be about 221/ 100,000/year. Therefore, patients who have undergone aneurysmal surgery have a high risk of developing a new aneurysm and /or an aneurysmal recurrence. Considering the great length of time it takes for an aneurysm to recur, a long-term follow up of over ten years should be established. Further, IV-DSA evaluations have proven useful for evaluating an aneurysmal recurrence.

View full abstract

A Rathke's cleft cyst that is entirely in the suprasellar region is rare, and only 17 Such cases have been reported in the literature. Herein we report one such case, that of a 58-year-old woman who was admitted to hospital because of a visual disturbance. Hospital tests revealed that her visual acuity was under 0.1 on both sides and a visual field examination uncovered left temporal hemianopsia. Further, CT scans showed a mass of low density in the suprasellar region, and MRIs revealed a mass of high intensity in the suprasellar region that extended to left cerebral peduncle. Although a radical or a partial excision, followed by radiation therapy, is widely recomended for craniopharyn-giomas, simple aspiration of the cystic fluid is advocated for a Rathke's cleft cyst. However, we could not preoperatively distinguish whether this mass was a Rathke's clef cyst or a cystic craniopharyngioma. Therefore, at time of surgery, an interhemispheric, trans-lamina terminalis approach was used for the purpose of performing a total resection. However, we did not perform a total resection of the capsule because tense adhesion of the cyst to the hypothlamus indicated that it was a Rathke's cleft cyst and aspiration was performed. The postoperative course was uneventful and the patient's visual acuity and visual field deficits improved.

View full abstract

Reported is the case of a 73-year-old male patient on maintenance hemodialysis for the past 8 years. He was admitted to hospital on May 10, 1994 because of a headache and a gait disturbance that had gradually grown more severe over a 2-week period. On examination, MRI revealed a large mass (4 x4 cm) in the brain stem that was severely compressing the brain stem at the left cerebellopontine angle. This finding suggested an acoustic neurinoma and decompression surgery became mandatory since the neurological symptoms progressively worsened. Thus, on May 25 a resection of the tumor was performed. Prior to the operation, however, frequent hemodialysis was initiated using nafamostat mesilate instead of heparin. Fruther, cerebellar edema was kept well controlled by external ventricular drainage and hyperventilation. As for the surgery, except for 2 part of the internal auditory canal, the tumor was resected totally. The postoperative course was uneventful, and the patient resumed his daily life on maintenance hemodialysis. Although reports of successful neurosurgery for patients on maintenance hemodialysis have appeared in the recent literatrure, the operative results do not seem to be entirely satisfactory. Important and difficult problems have yet to be solved in the perioperative management, specifically the tendency of bleeding in patients with chronic renal failure, fluid balances with respect to cerebral edema, hyperpotassemia, and similar manifestations during and after the surgery. These problems often neccesitate repeated hemodialysis by staff with technical skill. In this reported case, nafamostat mesilate was used in the hemodialysis and hemodynamic control was maintained with Swan-Ganz catheterization. In addition to these technical problems, the perioperative management of brain surgery for patients on maintenance hemodialysis is discussed.

View full abstract

We report an unusual case of spinal transient ischemic attack due to a mural thrombus in the thoracic aorta. A 62-year-old man suddenly developed a severe back pain, and noticed numbness and weakness of both lower extremities, which resolved within an hour. The patient was admitted to our institute due to the same attack. On admission, neurological examination revealed transverse myelopathy at the level of the 8th thoracic spinal cord. Although CT and MRI demonstrated no abnormal lesion in the spinal cord, a mural thrombus was detected in the thoracic aorta. We considered the mural thrombus occluded the radicular artery, resulting in spinal cord ischemia. He recovered fully with the conservative treatment, including platelet antiaggregant and thrombolytic therapy, and was discharged 18 days after the onset of symptoms. In a patient with rare spinal TIA, careful attention also should be paid to the possibility of an aortic lesion.

View full abstract

We report the case of a hypothalamic hamartoma associated with dysgenesis of the corpus callosum in a 4-year-old boy who was admitted to hospital because of gelastic seizures that had persisted for 3 years. Although a neurological examination on admission revealed no abnormal finding, his penis was large, 2.5x 6.0 cm in size. Magnetic resonance T1-weighted imaging demonstrated a mass with a relatively low intensity in the interpeduncular cistern, whereas on T2-weighted imaging this mass was depicted as being hyperintense. Additionally, this mass did not enhance on use of a contrast medium, and the corpus callosum was found to be dysgenetic. Hermonal research showed normal serum LH values, however, the FSH and testosterone values and the FSH response to an administration of LH-RH showed a pubertal pattern. Using a right peritoneal approach, samples of the patient's tissue were taken for a biopsy, and the results of a histological examination revealed nearly normal cortical tissue. However, the cytoplasms of the ganglion cells reacted positively to LH-RH immunohistochemical staining. Based on these findings the patient was diagnosed as having a hypothalamic hamartoma. Although several cases of hypothalamic hamartoma associated with other malformations, such as hydroce-phalus, porencephaly, poly-or syndactyly, and similar anomalies, have been reported, cases of a hypothalamic hamartoma associated with dysgenesis of the corpus callosum have rarely been reported. A hamartoma is thought to develop from 35 to 40 days after gestation, whereas the corpus callosum develops from the 6th to the 20th week. Based on the time disparity between the development of a hamartoma and the corpus callosum, to find an of hypothalamic hamartoma and dysgenesis of corpus callosum associationship between them at 6 weeks of gestation is indeed a rare event.

View full abstract

A case of cervical cord injury in a 34-year-old man that was caused by a stab wound is reported. He was involved in a fight and on admission to hospital he was unable to move. Gross inspection revealed two Stab wounds in the anterior and the posterior neck ; the latter wound was associated with cerebrospinal fluid (CSF) leakage. A neurological examination performed on admission revealed almost complete right hemiparesis, right hemihypesthesia and left hemihypalgesia, signs of a cervical hemispinal cord injury indicative of Brown-Sequard's syndrome. MRIs taken on admission disclosed the routes of the two stab wounds and a spinal cord injury associated with a small epidural collection of bloody CSF or a hematoma. After conservative treatment for several days, the patient's CSF retension gradually increased and CSF leakage was detected. Further, the patient complained of a radiating pain in the body trunk and both legs that was found to be caused by cystic compression. Thus, the patient underwent surgery 23 days after sustaining his injuries, and a dural defect and an incomplete hemitransection of cervical cord was found between C4 and C5 lamina. On accomplishing a laminectomy of the C4 to C5 region, the dural defect was closed with lyodura and the wall of the cyst was carefully removed. The patient's postoperative neurological signs greatly improved and he made good progress in rehabilitation. After being able to walk by himself, he returned to his occupation with no serious deficits. This is a rare case of a stab wound spinal cord injury, probably inflicted by a knife, that resulted in an excellent recovery from Brown-Sequard's syndrome.

View full abstract

The authors report a case of moyamoya disease in a 2-year-old male infant in which a unilateral obstructive process advanced to bilateral stenotic lesions within a period of 3 months. The Infant was admitted to hospital due to progressive right hemiparesis, a disturbance of consciousness, and an elevated fever. Magnetic resonance imaging (MRI) on admission revealed a cerebral infarction of the right frontal lobe. Further, magnetic resonance angiography (MRA) , taken at the same time, showed the lack of a signal emanating from the proximal portion and the distal branches of the right middle cerebral artery (MCA) . The results of the initial angiography confirmed the right MCA stenosis that had been indicated in the MRAs, and stenosis in the moyamoya vessels in the basal area, whereas the left internal carotid artery showed only mild stenosis in the terminal portion. Therefore, our diagnosis was "probable" moyamoya disease. For the first 3 months, the patient seemed to improve. However, MRAs taken 3 months after admission demonstrated a bilateral disappearance of the MCA signal. The angiographs that were taken at the same time showed a bilateral advance in the stenotic lesions and the moyamoy. a vessels. Thus, the patient underwent a two-stage, bilateral STA-MCA anastomosis. The patient's postoperative recovery was uneventful. It is generally accepted that moyamoya disease progres-ses, but no previous report was found such rapid progression in only 3 months. This case demonstrates the usefulness of MRA in diagnosing early-stage moyamoya disease, especially in infants.

View full abstract

A case of dural arteriovenous malformation (dural AVM) in the parasagittal region of a 63-year-old female is reported. This patient was admitted to hospital due to a severe headache in the left parietal region, although she had received no head trauma or an infectious disease. A neurological examination conducted on admission revealed no abnormal signs or symptoms. However, cerebral angiography revealed a dural AVM in the left parietal region, which was being perfused by the left middle meningeal artery and drained into the cortical vein. Further, no stenotic or obstructive findings were detected in the superior sagittal sinus. On undergoing surgery, a nidus in the dura mater was at the point of turning into an arteriovenous fistula ; this was extirpated successfully and a subsequent histological examination of a tissue specimen confirmed it to be a parasagittal dural AVM. The patient's postoperative course was uneventful. To our knowledge, this is the first case of the dural AVM in which a nidus has been histologically confirmed in the parasagittal region. Although the pathogenesis of a dural AVM is still a topic of some controversy, we think that some dural AVMs occur congenitally.

View full abstract

We describe a new monopolar coagulator that we have devised for microsurgery. This coagulator consists of a small ring-knife and a bayonet-type arm that can extend in size. This new coagulator is now commercially available. Under the guidance of an operating microscope, it can facilitate the resection of hard to resect hypervascular, deep-seated tumors, such as meningiomas.

View full abstract