Fourteen cases of primary central nervous system lymphoma (PCNSL) are reported with emphasis upon correlation between the clinical course and CT findings. All primary lesions were intracranially located, presenting either single or multiple intracerebral nodules with contrast enhancement on CT scan. Mental disturbance was the most common neurological manifestation on admission. All patients were given radiation therapy as the initial treatment except one, who showed complete remission in response to corticosteroid administration. Steroid induced tumor regression on CT in 4 out of 8 patients, including 3 cases of complete remission. The initial treatment induced complete disappearance of the tumor nodules showing contrast enhancement in all but 1 patient, who died in the course of the treatment. However, clinical improvement did not always follow the disappearance of the tumor on CT scan. The patients with mental disturbance and multiple tumors tended to show an inadequate response to treatment. During the follow-up period, 9 patients died. The cause of death was attributable to the uncontrolled growth of recurrent tumors, with contrast enhancement on CT, in only 2 patients. In the remaining 7, a diffuse low density area appeared in the deep cerebral white matter, with ventricular dilatation of varying degree in the follow-up period. When CT scan disclosed these findings, the patients showed a disability similar to that of normal pressure hydrocephalus, usually in a bed-ridden state, thereafter gradually deteriorating until death. In this study, the tumor nodules showing contrast enhancement seemed to be treated with relative ease. The diffuse low density, on the contrary, was much more difficult to deal with and was considered to be a major obstacle to improving the treatment results in PCNSL.

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In retrospective review of our malignant meningioma patients, we discussed about clinical analysis and treatment methods. Among 124 cases of surgically treated meningiomas, 11 cases were of malignant meningiomas, which includes 5 cases of atypical meningiomas, 4 cases of anaplastic meningiomas and 2 cases of papillary meningiomas. Duration of median follow-up was 73 months. The malignant meningiomas patients presented in more than 60 years of age and had poor outcome. Three of surgical treatment with Simpson's grade I had no recurrence. But the other 8 patients, with Simpson's grade II to IV surgical removal had recurrence (sizable regrowth of tumor) and the time elapsed to recurrence from surgical treatment had no statistically significant difference. Conventional radiotherapy was given to 8 cases postoperatively, but could not prevent the enlargement of such tumors. It was known that recurrence of tumor was unavoidable if the tumor could not be removed with Simpson's grade I. However, when the tumor, surgically treated with Simpson's grade II to IV, enlarged following the treatment, if removal of the tumor was performed as soon as possible, performance status of the patient sustained in good condition. The cause of death was not cerebral herniation but gradual deterioration of general condition caused by radiation necrosis following conventional radiotherapy, radical surgical treatment and deterioration of performance status by enlargement of the recurred tumor. We would like to propose as follows: 1. Surgery should be performed with Simpson's grade I , if possible. 2. Tumor progression must be found out by - study in symptom free period. 3. Cyto-reduction surgery should be performed to preserve the performance status. 4. Stereotaxic radiosurgery may be a suitable choice as a radiation therapy, instead of conventional radiotherapy.

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We studied ten cerebellar arteriovenous malformation (AVM) patients presenting with severe impairment of consciousness, in regard to the relationship between the clinical courses, imaging studies and surgical results. The preoperative level of consciousness was 200-300 (JCS). All patients showed respiratory abnormalities due to tonsillar herniation. In all patients, CT scans revealed a large hematoma at least 3 cm in diameter, but the AVM proved on operation or on angiography to be small. According to the Glasgow outcome scale, surgery was followed by good recovery (GR) in two patients, moderate disability (MD) in two, severe disability (SD) in two, a vegetative state (V) in one, and death (D) in three. The pupils of the six patients who underwent a relatively favorable recovery (2GR, 2MD, 2SD) exhibited miosis or reaction to light, whereas the pupils of the other four patients showed no light reflex. The intervals between onset and the clinical manifestation of tonsillar herniation were longer in the patients showing GR, MD, or SD than in those in whom V or D followed. There was no relationship between the surgical results and age at onset, interval from onset to admission, interval from admission to operation or size of hematoma. In our series, 40% of the poor risk patients recovered enough to require no assistance in their daily lives. We concluded that urgent surgical intervention is essential in cases of cerebellar hemorrhage caused by AVM, in which the pupils are not fully dilated and are responsive to light, even if there has been an episode of respiratory arrest in a deep comatous state.

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A emergency carotid endarterectomy can be carried out for the purpose of restoring the neurological functions or to treat high risk heart patients from a further stroke. In this regard, during the past 5 years, we have handled 12 cases that involved a carotid endarterectomy within 7 days following the latest ischemic cerebrovascular event. Six of these 12 carotid endarterectomies were performed on an emergency basis and all six patients were men : three had crecsendo transient ischemic attacks, and the remaining three had a stroke in evolution, with patterns that showed the waxing and waning of the signs and symptoms. In all cases, carotid angiography revealed severe stenosis (90% or greater) of the internal carotid artery ; additionally, ulceration was found in two cases. The average interval between the last ischemic cerebrovascular event and the carotid endarterectomy was 3 days. Postoperatively, all patient made a full recovery and no neurological deficits were noted on discharge. Surgical mortality was nil, and postoperative angiography revealed good patency of the vessel in all patients. In this series, the crecsendo transient ischemic attacks cases were thought to be caused by thromboembolic cerebral ischemia, and the cases of a stroke in evolution to hemodynamic cerebral ischemia. Based on our experience, we feel that an emergency carotid endarterectomy to be a recommendable surgical method that provides a most successful result for acute stroke patients manifesting either of the two patterns mentioned above.

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A new flow-control "on-off flushing device" for lumboperitoneal shunt has been developed. This device features a simple seasaw action and click sound. It can be easily operated by manual compression of the switch without the need of any special equipment, and its on-off function is highly reliable. Our preliminary studies suggested that it was satisfactory worked in the patients without severely disturbed consciousness to prevent complications such as overdrainage as well as to treat CSF leakage. It's clinical application is continuing to be investigated.

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Trigeminal neurinomas are difficult to remove when the tumors have a dumbbell configuration and extend into both the middle and posterior cranial fossa. Herein, the authors report the case of a recurrent trigeminal neurinoma which extended from the cerebello-pontine angle and prepontine space into the cavernous sinus, that was removed successfully by using a combined supra- and infratentorial transpetrosal approach (CTPA). This case involved a 45-year-old female referred to our clinic with right oculomotor, trigeminal, and facial palsy and right trigeminal neuralgia. Although a subtotal removal of the neurinoma had been performed three previous times by using a suboccipital approach, MRI revealed the tumor's recurrence. Both CT and MRI revealed that the tumor extended from right cerebello-pontine angle and prepontine space into the cavernous sinus, so that surgery was again performed, by means of a CTPA under facial nerve stimulation, and ABR and SEP monitoring. Because this was the fourth operation in this area, the anatomy was difficult to understand, and these monitors proved useful. A total removal was successfully performed. The postoperative course was uneventful, and the trigeminal neuralgia disappeared.

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Although the surgical treatment of an unruptured intracranial aneurysm (AN) has become an accepted procedure, the surgical treatment of an unruptured arteriovenous malformation (AVM) still remains a subject of controversy, and the authors herein report the case of an unruptured AN that was accompanied by an AVM of the posterior fossa. The patient, a 68-year-old woman, had tinnitus, and the CT and MRI findings suggested an AVM. Angiography revealed this AVM, which was accompanied by AN. The major feeding artery was found to be the inferior vermian branch of the right posterior inferior cerebellar artery, from which a berry AN was arising. Both lesion thus were treated by a one-stage operation, and the results have been satisfactory. Based on this experience and a study of pertinent eases in the literature, the authors have concluded that patients with both an unruptured AVM and an unruptured AN of the posterior fossa, as well as patients with hemorrhaging from an AVM or AN should be individually evaluated for possible treatment by surgery.

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The authors report the successful surgical treatment of 3 patients with midline vertebral artery aneurysms by using a transoral transclival approach. These cases are discussed below. Case 1: The 64-year-old female patient had a saccular aneurysm of the left vertebral artery on the midline with an acute subarachnoid hemorrhage. Thus, a transoral transclival approach was used and the aneurysm coated, because neck of the aneurysm was so broad. The patient recovered well and, on becoming able to ambulate, was discharged. Case 2 : The 67-year-old female patient had a wall dissection aneurysm of the right vertebral artery that was located in the midline and presented subarachnoid hemorrhaging. The aneurysm was successfully trapped using the transoral transclival approach. On recovery, the patient was discharged and showed no neurological deficit. Case 3; The 66-year-old male patient had a saccular aneurysm at the union of the vertebral arteries and presented acute subarachnoid hemorrhaging. Thus, a neck clipping of the aneurysm was performed using the transoral transclival approach. Postoperatively, the patient fully recovered with no complication. In all cases, to prevent CSF rhinorrhea, continuous spinal drainage was performed and tight packing of the bone defect with the femoral muscle and fiblin glue. For surgical treatment of a midline intercranial lesion, the authors believe that the use of the transoral transclival approach is an effective choice.

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Although reports in the literature have discussed the use of percutaneous transluminal angioplasty (PTA) for treating supra-aortic arterial stenoses, few reports have appeared with regard to PTA techniques for treating significant bifurcation stenoses of supra-aortic arteries. Thus, the authors herein describe PTA surgery that employed a kissing balloon technique (KBT) wherein two balloons were simultaneously inflated to prevent a side branch occlusion in a patient with stenosis that involved the bifurcation of the ostium of the left vertebral and the subclavian artery and succeeded in achieving sufficient dilatation. The surgery was successful and no complications occurred. Based on their results, the authors have found that the KBT technique is useful for the treatment of the supra-aortic bifurcation stenosis.

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The authors describe the case of a 16-year-old, female, moyamoya disease patient who had undergone a bilateral superficial temporal artery (STA)-middle cerebral artery (MCA) anastomosis and an encephalo-myo-synangiosis (EMS). Subsequently, she experienced repetitive transient ischemic attacks (TIAs) of hemiparesis whenever each anastomosed STA was compressed, especially when pressure was sustained by her elbows while watching television or reading a book. Bilateral external carotid ARTERIOGRAMS revealed that each MCA region had good filling via each anastomosed STA, the EMS and transdural anastomoses, but a cerebral blood flow (CBF) SPECT study, using ^<99m>Tc-hexameth-ylene-propyleneamine oxime, showed that the CBF in the ipsilateral MCA decreased whenever each STA was compressed. It thus was felt that each MCA in this patient was dependent on the blood flow supply via the anastomosed STA, and that the collateral reserve, supplied via the vertebrobasilar arterial system and the other external carotid artery system, was poor.

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The authors report the case of a 58-year-old woman with a severe subarachnoid hemorrhage (SAH) caused by a ruptured aneurysm at the junction of the vertebral artery (VA) and posterior inferior cerebellar artery (PICA), slightly distal to the site of the dural penetration. The patient had experienced a sudden onset of severe nuckal pain but showed no neurological deficits, and a CT scan taken on admission revealed that the SAH was mainly confined to the posterior fossa. Although the initial cerebral angiograms appeared to be normal, the patient became comatose on rebleeding. After conservative therapy was initiated, she became conscious and angiography was again performed 27 days after onset. This revealed left vertebral artery aneurysm just below the foramen magnum. Thus, a suboccipital craniotomy was performed and an aneurysm was seen at the VA-PICA junction ; this aneurysm was sited very low, slightly distal to the site of dural penetration. The aneurysm was successfully clipped without disturbing the lower cranial nerves. Postoperatively, the patient merely exhibited transient left hemiparesis and diplopia, presumably caused by a vasospasm. PICA aneurysms and related aneurysms of this region show a great variation in their site of origin from the VA. A PICA originates below the foramen magnum in 18% of cases, but a VA-PICA aneurysm that develops at the site of the dural penetration, as in this case, is extremely rare.

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The authors have used the potassium titanyl phosphate (KTiOPO_4 : KTP) laser for various craniotomies, and have evaluated its efficacy. The KTP laser has a wavelength of 532 nm, which is half the wavelenght of a neodymium: yttrium-alminum-garnet (Nd : YAG) laser, so that its energy level is very close to that of maximum absorption to hemoglobin and thus is beneficial for hemostatic cutting. Further, as the KTP laser's green light is visible after being delivered through a flexible quartz fiber to the operative field, this light allows the surgeon to set the target precisely. With the light bayonet handpiece, the laser can be introduced even through a minimun opening to deep seated skull base tumors. The laser also can be used in both the contact and non-contact modes by simply cleaving the tip of the fiber whenever polluted. Tissue damage caused by laser irradiation was also investigated when treating brain tumors of the rat cerebrum, and it was found that the thickness of thermal damage was no more than 1.5 mm when the laser mode was set for the usual tumor evacuation. These features of the KTP laser was thus considered to provide powerful advantages for use in microneurosurgery.

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