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Results of auditory brainstem response (ABR) and electrically elicited blink reflex (BR) recorded from 43 patients with severe brain damage within three days after the onset of illness were analyzed to assess the prognostic value of ABR and BR with respect to patient outcome evaluated by the criteria proposed by Jennett and Bond. It was possible to recognize, in recordings obtained from patients with severe brain damage, three basic patterns of BR as well as five patterns of ABR within three days after the onset. Three basic patterns of BR were composed of Type I, which closely approximated the BR of normal subjects except for moderately prolonged latency of R2, Type II, which indicated absence of bilateral R2 activities, and Type III, which showed absence of R1 as well as bilateral R2. ABRs were graded, in increasing order of abnormality, from Type I to Type V. Type I was almost normal pattern from wave I to wave V. Type II indicated prolonged latency or markedly reduced amplitude of waves IV and V. Type III showed absence of waves IV and V. Type IV had only wave I. Type V indicated absence of all waves. BR abnormalities significantly proved useful in predicting vital prognosis of the comatose patients with supratentorial lesion. In patients who had Type II of BR, additional studies of ABR enhanced the reliability of prediction of functional prognosis. On the other hand, ABR was recognized as stronger basis for predicting outcome in patients with infratentorial lesion. All patients with Type IV or Type V of ABR were expired within one month after the onset.(ABSTRACT TRUNCATED AT 250 WORDS)

Short latency somatosensory-evoked potentials were recorded from the human thalamus and the midbrain during stereotactic operations. Several subcomponents were recognized on the peak of N18. These were recorded with maximal amplitude at the border between the caudal portion of the thalamus and the rostral midbrain. Two positive-negative responses, not previously shown, were observed between P14 and N18. These responses were prominent in the rostral midbrain. These findings indicate that the ascending phase of N18, and the N18 itself, are the compound potential generated in the mesodiencephalic junction.

Matsumoto was the first to present the NIIC UltraSonic Aspirator for CT guided stereotactic aspiration of intracerebral hematoma. Based on the NIIC Aspirator, the authors have developed a useful tool for microsurgery by adapting conventional ultrasonic aspirators. This was done by making the aspirator lighter and more handy for use during microsurgical procedures. A newly devised apparatus using the Micro Ultra-Sonic Aspirator (MUSA) was applied clinically to surgical treatment for brain tumors, arterio-venous malformations (AVMs) and intracerebral hematomas. Using the MUSA system, it became easier to remove successfully tumorous mass and the nidus of AVM, because it minimized the risk of injury to the normal structures such as the surrounding brain tissue, vascular systems and the cranial nerves.

A long-term follow-up study of rostral mesencephalic reticulotomy (RMR) for pain relief is presented. 34 patients (24 males and 10 females) were operated. Ages ranged from 18 to 65 years. The follow-up period was 1-70 months. The overall effectiveness of RMR showed good relief of pain in 23 patients (67%). The study of effectiveness of RMR according to type of pain showed good relief of pain in 5 out of 6 patients (83%) with nondenervation pain, whereas satisfactory pain relief was obtained in 18 out of 28 patients (64%) with denervation pain.

Rostral mesencephalic reticulotomy (RMR) has been performed since 1973 for relief of intractable pain. The target area is in the midbrain reticular formation (MRF) bordering the periaqueductal gray matter at the superior collicular level. The target of RMR is 13--16 mm posterior to the midpoint of the AC-PC line and 5--8 mm below the AC-PC line. The laterality of the target is measured from the center of the aqueduct, ranging 5 to 8 mm from the midline. The rationale for this procedure is based upon the previous findings that the brain stem reticular formation plays a more important role above the spinal cord level than the lateral spinothalamic tract in the central conduction of nociceptive impulse. In the present study, intraoperative single neuron recording was made with tungsten microelectrodes from the human midbrain tegmentum in response to peripheral pinprick stimulation. These nociceptive neurons were classified into three groups in regard to the unit latency from the peripheral pinprick stimulation.

The occurrence of epileptic seizures is not rare after craniotomy. The authors examined the incidence of postoperative epilepsy in 150 patients of intracranial aneurysm. Anticonvulsants were given to all patients after operation, but in 12 cases anticonvulsants were discontinued because of liver dysfunction. One hundred and eight out of 138 cases (78%) were prescribed polypharmaceutically, and 30 of 138 cases (22%) were monopharmaceutically. The daily dose of anticonvulsants was as follows; diphenylhydantoin (DPH) was 150-300 mg, phenobarbital (PB) was 50-100 mg, valproic acid (VPA) was 600-1200 mg, and carbamazepin (CBZ) was 200-600 mg. Postoperative epilepsy occurred in 14 of 150 cases (9.3%); 13 cases with anticonvulsants, and 1 case without anticonvulsants. The site of aneurysm was as follows; 6 cases (10.3%) of AC aneurysm, 3 cases (9.7%) of MC aneurysm, 1 case (2.4%) of IC aneurysm, and 4 cases (21.1%) of multiple aneurysm. The interval between operation and epileptic seizure was ranged 2 to 57 months (mean 19.8 months); in 7 cases (50%) within 1 year, and in 13 cases (93%) within 3 years. The authors emphasize that prophylactic use of anticonvulsants is effective to control subclinical epileptic seizures, prescribing anticonvulsants to all patients after craniotomy in general. The medication of anticonvulsants for 3 years would be necessary for avoiding postoperative epileptic seizure.

As a new clinical approach for the purpose of mapping a lamina analysis, the present report deals with another landmark for insertion of the spinal needle in man other than the usual dentate ligament when performing a percutaneous cordotomy. Electrophysiological studies were made on 19 patients in order to determine the effect of electrostimulation with a bipolar concentric electrode, as well as to corroborate the position of the electrode radiologically. A new apparatus has been devised so that one can locate the target insertion point easily.

Difference in angles between horizontal section of Schaltenbrand & Bailey's atlas and horizontal section of CT based on Cantho-Meatal line is only 3.5 to 5.5 degrees. Therefore, the horizontal section of Schaltenbrand & Bailey's atlas can be utilized for analysis of the horizontal section of CT scan, because the basal ganglia are located approximately in the center of the cranial cavity. The lesions at the basal ganglia with superimposing technique utilizing the relation between horizontal section of Schaltenbrand & Bailey's atlas and analogue view of CT can be identified anatomically.

Somatosensory evoked potential elicited by median nerve stimulation at the wrist was recorded from five loci on the trajectory of stereotactic rostral mensencephalic reticulotomy. Four distinct positive waves followed by one negative wave, the peak latency being 16.3 msec, were recorded from the rostral midbrain reticular formation near the medial lemniscus. The four positive waves were named as I, II, III, and IV respectively. Peak latency of these positive waves was 12.6, 13.7, 14.7 and 15.8 msec respectively. The first two positive waves (I, II) corresponded to P13 and P15 recorded over the scalp. The other two positive waves (III, IV) changed their polarity to negative at the level of the ventral thalamus and formed the ascending limb of N20 recorded over the scalp. N16 was most prominent at the level of nucleus ventrocaudalis externus. These findings suggest that the ascending limb of N20 is composed of at least three components, wave III, IV, and N16. The present report is compatible with the investigations by Abbruzzese et al.2) and Eisen et al.11) that there are several distinct dipoles between P15 and N20 of somatosensory evoked potential in man.

EEG topography was investigated before and after surgical treatment in 4 patients with brain abscess aged from 5 to 13 years. According to the recording technique designed by Matsuoka and Ueno, the recorded EEG for each 5 seconds was analyzed to obtain square roots of power spectra for each band of delta (2-3.8 Hz), theta (4-7.8 Hz) and alpha (8-12.8 Hz) which were then added for the 60-seconds duration of each trial. After that, numerical matrix presenting the topographic distribution of spectral energy of each band were constructed and displayed as color images. In addition, the EEG topographies of brain abscesses were compared with the CT scans simultaneously obtained. In all of four cases before surgical treatment of the brain abscess, the location of the focal delta wave on the EEG topography was more closely related to the site of brain abscess comparing with its correlation between the location of the delta focus on the conventional EEG and the site of brain abscess. In contrast, as for the theta wave, there was no prominent correlation to the site of the brain abscess. In the early stage of 10-15 days after aspiration of the brain abscess, the most characteristic change of the EEG topography was an approximately 25% reduction of the maximum equivalent voltage of delta band with associated disappearance of the sharply located focal delta wave being noted before aspiration.(ABSTRACT TRUNCATED AT 250 WORDS)

A new apparatus is made for metrizamide cervical myelography. One part of the apparatus is a frame for immobilizing the head and the other is an assembly for guiding spinal needle insertion by lateral puncture. The head frame is made of concave plastic and three rubber discs for immobilizing the forehead and bilateral temporal region. The second piece of apparatus for guiding spinal needle insertion is movable in three directions: up and down, right and left and forward and backward. The sterilized guide made of acrylic is attached. The spinal needle is inserted along the groove of this sterilized guide. The apparatus makes it possible to locate the insertion point easily for the metrizamide cervical myelography by lateral C1-C2 puncture method in prone position, since the location of the tip of the inserted needle can be determined by the aid of lateral cervical x-ray and 10 mm scale, even if image intensifier of TV display screen is not available.

Recently, the brainstem pathways of bilateral late reflexes (R2) of electrically elicited blink reflex have been well established. An afferent delay or block of the late reflexes is closely related to a lesion of the lateral medullary portion. The chronological alteration of blink reflex (BR) was studied to compare with radiological abnormalities on MRI in a patient with lateral medullary infarction on the right side. A diagnosis of Wallenberg syndrome was made clinically and location of the lesion was identified in detail by MRI. The infarcted region which was well demonstrated as an increased intensity area on SE images obtained 52 days after the onset of symptoms was much smaller than that on SE as well as on IR image 21 days after the onset of symptoms. Therefore, it was concluded that more than half of the increased intensity area on the SE images obtained 21 days after the onset of symptoms recovered from the condition of being extremely damaged by ischemia on the right lateral medullary portion in this patient. On the other hand, in the initial BR 26 days after the onset of symptoms, the late reflexes (R2) were consistently absent bilaterally when the affected side (right) was stimulated and normal when the normal side (left) was stimulated. This type of BR abnormality is compatible with an afferent block of late reflexes (R2). The early reflex (R1) was normal on either side. Whereas in the second BR at 55 days after the onset of symptoms, the late reflexes turned to be normal in latency when the right side was stimulated.(ABSTRACT TRUNCATED AT 250 WORDS)

Significance probability mapping (SPM) of brain electrical activity first described by Duffy et al. is useful tool for studying functional aspects of brain disease. Z-statistic SPM is able to identify the area of brain electrical activity deviated with statistic significance from the control group. The problem of this method is, however, that the nature of deviation, i.e., whether it is increase or decrease of electrical activity, can not be displayed. From this point of view, we attempted to use modified z-statistic method. Statistically deviated region and its nature can be clearly displayed on the same picture by analyzing EEG with this method. This method can be applied to SPM of evoked potentials. SPM is not yet complete method for the assessment of brain electrical activity, but there is much room for adopting other statistic method that is more suitable for the aim of the study. Functional aspects of the brain will be more readily clarified by the use of modified SPM and by combination with findings of CT scan, NMR and PET that can give morphological and metabolic information.

The effect of long-term anticonvulsants on bone change was evaluated by microdensitometric method (MD method) in 221 outpatients of Neurological Institute Tokyo Women's Medical College. Laboratory findings including serum Ca, P, Al-p were compared with severity of bone change. Following results were obtained; In 221 patients, 159 cases (72%) were normal, 31 cases (14%) were in the initial stage of abnormality, 23 cases (10%) in grade I, 7 cases (3%) in grade II and one case (1%) in grade III of abnormality. Incidence of abnormality was high in the age of 26-35 years old and in the age over 56 years old. Total dose, serum concentration of diphenylhydantoin (DPH) as well as phenobarbital (PB) and also duration of administration of PB correlated positively with severity of bone change. Duration of administration of DPH and valproic acid (VPA), total dose and serum concentration of VPA did not correlate with severity of bone change. Serum Ca correlated with severity of bone change, but P and Al-p did not correlate with severity of bone change. Pattern of bone change was estimated by two parameters of MD method (MCI and GSmax). Results showed that most of the osteopathy (grade I-III by MD method) fell into osteoporotic type. Based on these results, it is suggested that roentgenologic and biochemical supervision of the patients is required during long-term anticonvulsant therapy.

CT-guided stereotactic brachytherapy has been performed for the deep-seated malignant gliomas using the double-catheter after-loading method. The catheter system consists of two coaxial polyethylene tubes with closed tips. The outer catheter is 3.0 mm in outer diameter and 2.4 mm in inner diameter. The inner catheter is 2.0 mm in outside diameter and 1.4 mm in inside diameter, and contains the radioactive sources. Localization of the target volume is determined by the preoperative findings of computed tomography (CT), magnetic resonance imaging (MRI), and cerebral angiography. Dosimetry and dose planning are so finalized for the target volume as to be irradiated interstitially more than tumoricidal dose. After stereotactic biopsy of the deep-seated brain tumors, stereotactic implantation of the outer catheters is performed using Iseki Stereotactic System in the CT room. Burr holes had been previously opened in the operating room. The inner catheters containing nonradioactive sources (dummy sources) are inserted, and skull X-p is taken to confirm the position of the dummy sources, and to calculate the dosimetry by computer. The inner catheters are replaced with catheters containing radioactive sources (226Ra) in the irradiation room. 226Ra sources deliver at least 500 rads/day (approximately 20 rads/hr) to the target volume as interstitial irradiation. Two patients of malignant gliomas treated with this procedure were shown as representative cases. These patients underwent CT-guided stereotactic brachytherapy as "boost" combined with conventional external irradiation.(ABSTRACT TRUNCATED AT 250 WORDS)

Ninety consecutive cases of hypertensive intracerebral haematoma were treated with CT guided stereotactic evacuation. The patients were composed of 61 males and 29 females, ranging from 42 to 87 years old. The location of haematoma was either in the putamen (59 cases) or in the thalamus (31 cases). The average volume of the evacuated haematoma was 21.4 ml in the putaminal haematoma and 14.0 ml in the thalamic haematoma. Postoperative follow-up study in 46 patients showed good recovery of neurological deficits both in putaminal and thalamic group. Criteria of surgical indication of CT-guided stereotactic evaluation of intracerebral haematoma were advocated based on the author's clinical experience.

There have been a few reports about intracranial giant aneurysms treated by intracranial direct approaches. Especially, for giant aneurysms of the internal carotid artery, direct operation has been thought to be difficult to perform because of the anatomical particularity and the danger of rupture during surgery. So the cervical carotid ligation has frequently been indicated. However, the carotid ligation does not relieve the symptoms caused by the giant aneurysm as an "intracranial mass lesion". The authors have reported here, a cured case of a giant aneurysm of the intracavernous portion of the internal carotid artery, to which, as the first step, ligation of the internal carotid artery in the cervical region was performed, and as the second step, endaneurysmorrhaphy was carried out for the remaining symptoms caused by the "intracranial mass lesion". Furthermore, the surgical techniques for treatment of giant aneurysms of the internal carotid artery were discussed citing literatures, and the authors concluded that the combined operation of carotid ligation and endane-urysmorrhaphy could be effective to giant aneurysms in this region. Meanwhile, a new concept concerning the anatomy of the carotid-cavernous region already proposed by Bedford, was confirmed by our observation at operation. It may be considered that the intracranial direct approach to aneurysms in this region and also to carotid cavernous fistulae should more frequently be indicated than ever performed, according to the new concept of the anatomy in this region.

In order to identify the location of the electrode tip during percutaneous retrogasserian glycerol injection (PRGI), the blink reflex (DBR) following direct stimulation of the trigeminal complex (the gasserian ganglion, trigeminal rootlets, or the 3rd division of the trigeminal nerve) was obtained from 6 patients with trigeminal neuralgia. 1) The waveform of the DBR was very similar to that of the blink reflex (BR) elicited by percutaneous stimulation of the 1st division of the trigeminal nerve. However, the latency of early reflex (R1) as well as late reflex (R2) of the DBR was approximately 2 msec shorter than that of the conventional BR. 2) When the electrode tip was introduced into the gasserian ganglion, the DBR showed the largest response under the same recording condition, whereas the DBR was not recorded when the tip of the electrode was placed into either the arachnoid space or the subdural space. The each DBR response, however, showed the same configuration when the electrode tip was situated at the territory of the 1st, 2nd or 3rd division of the trigeminal nerve within the gasserian ganglion or the trigeminal cistern. 3) The DBR always appeared under the anesthesia with the intravenous administration of 10 mg diazepam and 30 mg pentazocine. 4) Based on the present study, the DBR proved to be an usuful parameter in determining whether the electrode tip is introduced into the trigeminal complex or not, particularly in the case of patients having no reliable sensory response to electrical stimulation.

During the last 2 years, 46 cases of hypertensive intracerebral hemorrhage in the basal ganglia were treated by CT guided stereotactic aspiration and their outcome was evaluated in terms of the rate of hematoma removal, the change of consciousness level and the recovery of motor and sensory functions. They are aged from 45 to 79 years old, the average 56, and aspirated 1 to 24 days after the onset, two third of them being within 1 week. The whole procedure was done in the CT room under direct CT guidance and by one trial. In putaminal type hemorrhage, the removed hematoma volumes ranged from 9 to 48 ml, average being 23.7 ml, in thalamic type from 5 to 29 ml, average being 15.5 ml. The average rate of removal was 81.1% in 30 cases within 1 week. In most cases, preoperative consciousness was not severely disturbed, in putaminal type, 19 were alert or confused, 4 somnolent, 5 stuperous and in thalamic type, 6, 6, 3 respectively and 2 were semicomatous, one of them had herniation sign. In putaminal type all but 2 cases recovered to alert or confused state, the first one had postoperative bleeding and the other was already apallic preoperatively. In thalamic type, we lost 3 cases, 2 by gastrointestinal bleeding and 1 DIC, by rehemorrhage 2 months after the operation. All but one who was semicomatous preoperatively recovered to alertness. In motor function, some cases of the putaminal bleeding with intact internal capsule remained hemiplegic. On the other hand, most of the cases with partial destruction of the internal capsule on CT recovered well in both types of hematoma.(ABSTRACT TRUNCATED AT 250 WORDS)

During the last 3 years, 46 cases of hypertensive intracerebral hemorrhage were treated by CT-guided stereotactic surgery. Our present report is concerned with the evaluation of this procedure in the treatment of hypertensive intracerebral hematoma, in terms of the rate of aspirated hematoma and follow-up study of patients. It is difficult to draw any definite conclusion about the operative indications. CT-guided stereotactic aspiration, however, can be evaluated as a less invasive and more definitive treatment of intracerebral hematoma in the basal ganglia and thalamus.

67 cases of various functional disorders of the diencephalon were examined by EMI scanner. The patients were composed of 38 cases of parkinsonism, 7 cases of thalamic syndrome, 6 cases of choreoathetoid movement, 2 cases of dystonia, 11 cases of involuntary movement of unknown etiology and 1 case of torticollis, tic, and ballismus, respectively. In parkinsonism, 79% showed diffuse cerebral atrophy, 5% had focal low density in the substantia nigra and the thalamus, whereas 16% remained normal. Pre- and postoperative assessment with CT scan was briefly discussed with reference to stereotactic surgery of the diencephalon.

Immunoreactive beta-endorphin in the third ventricular fluid was measured in response to electrical stimulation of the periaqueductal gray matter in 8 patients with intractable pain during rostral mesencephalic reticulotomy for pain relief. In all patients, marked increase of immunoreactive beta-endorphin was observed. On the other hand, in cases of electrical stimulation of the zona incerta performed during stereoencephalotomy, in 5 patients with involuntary movement, immunoreactive beta-endorphin in the third ventricular fluid did not show any significant change. The authors conclude that the increase of immunoreactive beta-endorphin on electrical stimulation of the periaqueductal gray matter is not a nonspecific response to brain stimulation but a specific response in regard to cerebral localization of endorphins. Direct correlation between pain relief and periaqueductal gray stimulation is also questioned.

The authors devised a stereotactic apparatus for percutaneous cordotomy based on the experience of 191 percutaneous high cervical cordotomies on 150 patients suffering from intractable pain. This apparatus has two major components. One is a head and neck holder and the other is a guide and marker system. The head and neck holder contains fixed neck holder and head holder which can be movable in vertical direction. Using these holders, the operator can keep the patient's neck in neutral position. The marker system contains two markers of origin and a 10mm scale which indicates center line as well. The guide system, stereotactically designed, is movable in three direction and acrylic guide groove is attached. The guide needle for percutaneous cordotomy is inserted along the guide groove. The guide and marker system can be attached in both sides of the head and neck holder, therefore, the operator can insert the needle in both sides of the patient. This apparatus makes it possible to locate the target stereotactically for percutaneous cordotomy, since location of the inserted needle can be determined with the aid of cervical X-ray, even if there is no image intensifier of TV display screen available. Therefore it can be possible to reduce the X-ray exposure of the patient.

Combining whole-body CT scan with a stereotactic system, the authors have developed and applied clinically an apparatus which readily provides intraoperative CT images, making it possible to confirm the location of the target point and ascertain the intraoperative environment. It takes about 9 s to obtain a CT image. Our purpose is to make stereotactic surgery, a kind of blind surgery, as safe and reliable as a visualized procedure by intraoperative CT scanning. By the method, in which there is very little invasion under local anesthesia, evacuation of deep-seated intracerebral hematomas as well as brain abscesses and also biopsy or brachytherapy of brain tumors in the brain can be done with safety and reliability.