The treatment and outcomes of 44 large (over 15 mm) or giant (over 25 mm) intracranial aneurysms among 50 consecutive cases have been analyzed. STwenty-three cases received direct surgery, 15 cases underwent parent artery occlusion with or without bypass procedures, and 6 cases were given direct embolization. With regard to the results of these treatments, 70% had excellent or good outcomes. However, internal carotid-ophthalmic and basilar aneurysms had relatively poorer outcomes, with 60% of the former and only 33% of the latter cases having been assessed to have had good or excellent outcomes. Premature ruptures, parent artery stenosis, and/or perforator injuries during surgery were found to be the main causes for cases with poor results. In contrast, good results were obtained when treating aneurysms at other sites. Based on these findings, it thus has been concluded that parent artery occlusion with or without bypass surgery or intravascular surgery may be the better choices of treatment for many patients with giant intracranial aneurysms.

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This paper discusses aneurysms of the cavernous portion of the internal carotid artery, specifically 49 asymptomatic (44 patients) and 12 symptomatic (12 patients) unruptured aneurysm of the cavernous portion of the internal carotid artery that were surgically treated. All asymptomatic aneurysms were operated on directly (neck clipping : 48 aneurysms, trapping : 1 aneurysm) . The assigned grading of the Glasgow Outcome Scale was I for 43 patients and II for 1 patient. Major complications encountered were oculomotor nerve palsies and visual disturbances. Further, oculomotor nerve palsies appeared postoperatively in 19 patients but all were transient. Also, visual disturbances appeared in 5 patients. All symptomatic aneurysms were giant aneurysms and were treated directly in 8 patients and by an internal carotid ligation plus an EC-IC (extracranial-intracranial) vein graft in 4 patients. Preoperative oculomotor nerve palsies and symptoms of trigeminal neuralgia all disappeared after the surgery. Recovery from abducens nerve palsy that had affected 8 patients was complete in 5 patients, partial in 2 patients and worsened in I patient. Based on the surgical findings, these aneurysms of the cavernous portion of the internal carotid artery (infraclinoid aneurysms) can be classified by site into 3 groups, I, II, and III. Group I aneurysms are located distal to the distal dural ring and project ventromedially. Group I A aneurysms are distal to the origin of ophthalmic artery, and Group I B aneurysms are proximal to the artery. These Group I aneurysms originate below the level of the anterior clinoid process and are subdural aneurysms. Group II aneurysms originate between the distal ring and the proximal ring. Group II aneurysms are pericavernous sinus aneurysms that sometimes grow into the subdural space beyond the distal ring. Group III aneurysms are located proximal to the proximal ring and are genuine intracavernous aneurysms. These classifications are extremely useful when selecting the aneurysms amenable to surgery and the surgical procedures to be used.

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Out of 600 cases examined for the presence of a brain disease in a screening system for healthy volunteers called "Brain Dock", which began in March 1988, this paper describes the characteristics and treatment of 37 unruptured intracranial aneurysms detected in 36 cases. To detect these aneurysms, intra-arterial digital subtraction angiography (IA-DSA) was the method used to screen the first 370 cases and magnetic resonance angiography (MRA) for the subsequent 230 cases. The IA-DSA detection rate was 6.8% whereas the MRA detection rate was 4.8%, with no statistically significant difference seen between these two figures. However, the detection rate in females (7.8%) was higher than in males (5.1%). Further, 94% of the detected aneurysms were smaller than 10 mm, and their location differed from patients with a ruptured subarachnoid hemorrhage (SAH). There was a low incidence of anterior artery aneurysms (22%) and a higher incidence of internal carotid artery aneurysms (38%), particularly of the C2-3 and C3 (16%) regions. Finally, those with a family history of an SAH within the second degree of consanguinity showed a higher incidence of aneurysms (15.5%, p<0.01). Twenty-six cases (26 aneurysms) underwent surgery, and in all cases, neck clipping of the aneurysm was performed with no significant postoperative morbidity.

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For the purpose of reducing the risk of ischemic cerebrovascular complications in the perioperative stage of carotid endarterectomy (CEA), we attempted to estimate the probability on the early detection of a hyperaggregable and hypofibrinolytic state. Peripheral fibrinolytic activities were investigated with the venous occlusion (VO) test, the changes in platelet aggregation (PA) and fibrin or fibrinogen degradation products (FDP) before and after CEA. The patients were in a hyperaggregable and hypofibrinolytic state before and after CEA. The PA values induced by adenosine diphosphate (ADP) or collagen were measured by turbidimetric and impedance aggregometry and correlated with the changes in the fibrinolytic parameters before and after VO. In the VO test, the best correlation was seen between the values of ADP-induced PA measured by the impedance method and FDP as a representative fibrinolytic parameter. Furthermore, a significant correlation was evident between the values of ADP-induced PA measured by the impedance method before and after CEA or VO test and the changes_ in FDP before and after VO test. The results suggested that the reactivity of ADP-induced PA measured by the impedance in the preoperative VO test is a useful indicator for predicting a prethrombotic state due to hyperaggregation and hypofibrinolysis in the perioperative stage of CEA.

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We have reviewed the clinical files of 440 consecutive patients treated between 1980 through 1993 for a chronic subdural hematoma (CSH). Of the 440 patients, 327 were male and 113 were female, and their ages ranged from 6 months to 94 years (mean : 65.5 years). We divided the 440 patients into two age groups: those who were 70 or older (213 patients), and those who were younger than 70 (227 patients), and compared their clinical features. The aged group contained a higher number of females than did the younger group (31.9% versus 19.8%), a lower incidence of loss of consciousness at the moment they sustained their head traumas (15.0% versus 30.1%), and a lower incidence of symptoms and signs indicating an increase of intracranial pressure (21.1% versus 51.5%). In comparison to the younger group, immediate postoperative recovery was somewhat lower in the aged group, but the percentage of those who made a good recovery did not significantly differ between the two groups when patients who had associated diseases, such as degenerative or cerebrovascular diseases, were excluded from the analysis.

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Aerosolized fibrin glue has been widely applied on neurosurgery to prevent cerebrospinal fluid leakage through dural sutures. This study describes processes of absorption of fibrin clot used on the dura mater. Six specimens of fibrin clot were obtained by second surgery 11 upto 285 days after the first surgery. Approximately 2 weeks after the surgery, a membranous fibrin clot was partially dissolved and absorbed by densely infiltrating inflammatory cells. The cells were predominantly neutrophils, and in part macrophages. A specimen pulled apart from the autologous dura mater 4 weeks after the surgery was replaced with fibrous connective tissue composed with loose collagen fiber networks. Lymphocytes migrated in place of phagocytes. Infiltration and proliferation of fibroblasts were seen and endothelial cells formed small vessels. In part, however, fibrin clot remained. The vascular connection was observed between the granuloma and the dura mater. After 10 months, fibrin clot was replaced with mature granuloma composed of collagenous connective tissue with scarce eosinophil migration. On the other hand, fibrin glue sprayed on a processed human dura mater was hardly resolved compared to that on autologous dura and remained as a fragile membranous clot after 4 weeks or later. It was speculated that a clot resolusion preceeding to a granuloma formation may induce delayed cerebrospinal fluid leakage, especially on the non-vascularized artificial dura mater.

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Detailed flow velocity analysis, including pulsatile and slow step-by-step movement of CSF (cerebrospinal fluid) at the craniospinal junction was conducted by the Integration Method of magnetic resonance (MR) imaging. The study covered 13 cases in which some central nervous system disorder was suspected, of having some central nervous system disorder, but neuroimaging indicated no sign of any disorder. The patients are ranging in age from 7 days to 60 years. The Integration Method of MR velocity image, originally established for quantitative measurement of CSF slow movement, composed of two-step analises of a pulsatile velocity measurement and its integration. Velocity of CSF step-by-step movement in the ventral subarachnoid space (C1-C2) was measured at 100-250 mm/min, and this value was faster than those of dorsal and lateral side (50-100 mm/min). Maximum velocity was attained around the age of 10. The relationship between pulsatile and slow step-by-step movement in the ventral subarachnoid space was positively linear but not in dorsal and lateral subarachnoid space. It also was found that the direction of slow movement in this area can be classified four ways. These findings disclose a variability in CSF flow around the cervical spine. The method we used can non-invasively scan CSF slow movement in detail, and this movement possibly is related to the bulk flow of cerebrospinal fluid.

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The authors have conducted a clinical analysis of 46 patients who underwent the removal of an acoustic neurinoma by mean of the Rand-Kurze suboccipital transmeatal approach between 1984 and 1989. No correlation was found between the tumor size and preoperative pure tone average (PTA) and the auditory brain stem response (ABR). With regard to tumors larger than 2 cm, 58% of patients with CT-indicated low density tumors had good hearing and 7% of those with iso-dense or mixed density tumors had PTA of less than 50 dB (p<0.01). An adhesion between the acoustic nerve and the tumor capsule was observed in patients with a higher PTA (35% in PTAs<50 dB vs 71% in PTAs>70 dB, p<0.05) and poorer ABR findings (33% of Type 1, 30% of Type 3, and 93% of Type 4 patients, p<0.05 both in Type 1 vs Type 4 and Type 3 vs Type 4 patients). An adhesion between the brain stem and the tumor capsule in tumors larger than 2 cm was also present in those with higher PTAs (22% in PTAs<50 dB vs 71% in PTAs>70 dB, p<0.05) and in 75% of those with a Type 4 ABR. Preservation of hearing was achieved in 5 (43%) of 12 patients with a preoperative PTA of less than 50 dB and a speech discrimination score (SDS) of over 50%. The size of the tumors in the hearing-preserved group (11 ± 8.6 mm, m±sd) was significantly smaller than that of the hearing-10st group (32.1 ± 9.8 mm). Preoperative SDS was significant]y higher in the hearing-preserved group, but the differences in the PTAs and ABRs between the two groups were not significant. An adhesion between the acoustic nerve and the tumor capsule was found in only one patient of the hearing-preserved group but in three patients of the hearing-lost group. For this single patient with a medium-sized adherent tumor, a near-total removal (a small fraction of a tumor capsule that had firmly attached to the acoustic nerve was intentionally left) was provided and was felt contributory to the preservation of hearing. A disturbance of hearing in the presence of an acoustic neurinoma may not be dependent on the tumoral size but rather on the tumor's contents, pressure exerted on the cochlear nerve, or a tumoral invasion of the nerve and/or the brain stem. However, hearing can be preserved in patients with tumors that are small or easily separable from the acoustic nerve and have a higher SDS. Also, to preserve heaving, a near-total removal of tumors adhering to the acoustic nerve is recommended.

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The authors report a series of 50 cases of unruptured aneurysms, admitted and treated over a period of 8 years and 8 months (1984. 11. 1-1993. 6. 30). These aneurysms were discovered in two types of circumstances : 1) associated with a ruptured aneurysm, but treated through a second procedure (35 cases, 36 aneurysms) : and 2) after the onset of various neurological symptoms other than subarachnoid hemorrhage (15cases). Giant aneurysms were excluded from this series. Overall, these 50 patients harboured on aneurysms, and 41 patients (80%) were operated upon. Of the 41 patients who were operated on, there were five cases of postoperative complications, including two cases of rupture, one brain stem ischemia, one status epilepticus, and one respiratory failure. The rupture cases did not recover : one died and the other fell into a vegetative state. The remaining three patients, however, recovered, without disability, with time or through treatment. Of the patients who developed rupture in spite of surgery, one received only coating of the aneurysm and the second, who had two unruptured aneurysms, received clipping for only one aneurysm, while the other remained unsecured. This experience suggests that if intact aneurysms (especially multiple cases) were treated surgically to prevent later rupture, careful preoperative evaluation of the patients and postoperative intensive care are essential. If neck clipping is not possible, an endovascular approach should be considered.

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This paper describes a surgical technique that modifies the conventional suboccipital craniectomy for cerebellopontine angle lesions. Briefly, a patient is first placed in a lateral park-bench position, after which a linear longitudinal skin incision approximately 1 cm posterior to the mastoid process is made while preserving the lesser occipital nerve. Muscle dissection is then carried out as each anatomical layer is reached. Next, the sternomastoid is detached from the cranium and turned out anteroinferiorly, and the splenium capitis is reflected posteroinferiorly in the same manner. On reaching the deep layer, the longissimus capitis, the posterior belly of digastric muscle, the superior oblique and the major rectus capitis are identified and reflected in the direction of their origins. A burr hole is then made adjacent to the asterion, after which the craniectomy is pursued, using a hand-held rongeur and an air-dril1 while the posterior one-third of the sigmoid sinus is exposed. Removed bone chips are kept sterile during the course of the surgery. The dura is incised in semicoronal shape, based on the contour of the sigmoid sinus. The dural flap is fixed by firm suturing to the connective tissue of the mastoid process. Simultaneously, this enables a part of the sigmoid sinus to be turned out anteriorly. Opening of the cisterna magna and aspiration of cerebrospinal fluid (CSF) immediately reduces the tension of the cerebellar hemisphere. The craniectomy enables the offering of an optimally short and direct operative field to the cerebellopontine angle, with intradural procedures even possible without a brain retractor. After the intradural procedures are completed, cranioplasty is performed using the removed bone chips mixed with a spray of fibrin glue, after which the muscles are repositioned to their original sites by suturing. We have concluded that this surgical technique has enabled a reduction in pressure that a brain retractor can inflict on the cerebellum and the elimination of postoperative CSF leakage.

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Intraoperative monitoring of the ocular motor nerves was performed in 29 patients during skull base surgery. The oculomotor nerve (CN III), the trochlear nerve (CN IV), and the abducens nerve (CN VI) were electrically stimulated intracranially, and the compound muscle potentials were recorded from the inferior rectus muscle, the superior oblique muscle, and the lateral rectus muscle, respectively. The success rates of this monitoring were 92% (23/25) for the CN III, 50% (4/8) for the CN IV, and 89% (8/9) for the CN VI. In 14 patients, neuromuscular blocking agents were administered continuously, with the doses controlled to elicit 10% of a single twitch response. During the controlled neuromuscular bockade, monitoring of the cranial nerves proved feasible. Based on these results, we thus have concluded that monitoring of the ocular motor nerves is useful for identifying the cranial nerves and can reduce the incidence of surgical complications.

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The authors report the case of a 46-year-old man who was diagnosed as having a malignant fibrous histiocytoma (MFH) that had extended to the intracranial region from the temporal bone. A MFH is the most common type of soft tissue sarcoma ; however, it is rarely sited in the head and neck. In this case, despite a wide resection, we could not perform adjuvant therapy because the tumor had rapidly regrown. Early diagnosis, a wide resection, and radiation therapy are very important in the management of this disease.

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We describe a case of a patient who complained of visual perseveration, an overlapping of a pereived object. Visual perseveration is a phenomenon usually caused by the presence of a tumor in which a previously perceived vision overlaps into the subsequent full visual field for two to three seconds whenever the subject's eyes are turned. In this case, this phenomenon completely disappeared on removal of the tumor. It is thought that the visual perseveration was caused by a falcotentorial meningioma that compressed both occipital lobes and the corpus callosum.

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An adenoidal cystic carcinoma (ACC) is well recognized for its characteristic pathological features. The majority of ACCs occur in the salivary glands of the neck and oral cavity but rarely in the orbita. Herein we report two cases of an ACC that arose from the lacrimal gland in which the clinical presentations were significantly different. The proliferative potential in both cases was estimated by an immunostaining method using the MIB-1 antibody. The first patient was a 63-year-old man who had suffered from headaches, double vision, and right proptosis for 2 months prior to his first hospital admission. CT scans demonstrated a defined, right lacrimal gland tumor which was resected subtotally, after which the patient was given irradiation. A histological examination showed the tubular structures of an ACC that were substantially accompanied by solid structures. Sixteen months later, however, an extensive intracranial invasion with a minimal local recurrence was discovered. Therefore, a second operation was performed and was followed by irradiation. Thus, local control was successfully achieved, though there was evidence of a small residual tumor. Pathological findings revealed the predominance of a solid pattern. The MIB-1 positive rate was ll.8%. There was a further recurrence 1 year later. The second patient was a 45-year-old man with a 2-month history of diplopia and the attenuation of optic acuity of the left eye. A radiological evaluation demonstrated the presence of a round mass in the left lacrimal gland. This mass was totally excised including the surrounding soft tissue, after which irradiation of 5,l00 cGy was given postoperatively. Inspection of a surgical specimen revealed a cribriform ACC with no other structures. MIB-1 immunostaining showed a positive rate of 6.8%. At 16 months postoperatively, the patient remains free of a recurrence. ACCs comprise about 10% of all salivary neoplasms and thus represent a definite clinicopathological entity. Although enlargement of this tumor is slow, a local recurrence is common and a metastasis can occur as life is prolonged, indicating its potentially malignant behavior. Previous reports and the results of MIB-1 immunostaining suggest that a solid pattern ACC can be more aggressive in both its clinical and pathological aspects than its tubular or cribriform subtypes. MIB-1 immunostaining is applicable even for paraffin-embedded tissue specimens and the procedure is recommended for achieving a prognosis. A wide excision including an adequate margin offers the best chance for cure with palliative radiotherapy given postoperatively to inhibita a recurrence.

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The authors report a case of a 56-year-old man who was found to have a bacterial aneurysm in the cavernous portion of the internal carotid artery secondary to cavernous sinusitis. Serial angiography revealed that the aneurysm had enlarged and it was successfully treated by trapping with an STA-MCA anastomosis. Bacterial aneurysms of the cavernous carotid artery are rare, and only 26 cases have been reported in the Japanese and English literature. Based on these reported cases, the characteristics of this disease are as follows: 1) it predominantly occurs in children (48.1%) and in males (63%) ; 2) the most common etiologic factors are an infection of the furuncles of the face, sinusitis, middle ear infections, and dental infections (57.7%) ; and, 3) meningitis is also a very common complication (70.4%) . Serial angiography provides a method to check aneurysmal enlargement that usually occurs (55%), and the clinical outcome of treated cases is good (96.3%). Based on our experiences and on what has been reported in the literature, if serial angiography shows aneurysmal enlargement, surgical treatment should be considered.

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Reported is a rare case of a brain abscess that occurred as a result of rhinocerebral mucormycosis. The patient, a 37 year-old male, was hospitalized because of right facial pain and blurred vision. The CT scans revealed an isodense mass in the right side of the ethomoid, maxillar, and sphenoid sinuses and in the orbital apex. Also, an area of low density area was seen in the right frontal lobe, and a transnasal biopsy revealed mucormycosis. Because of these findings, intensive treatment with antifungal drugs was initiated ; however, his visual acuity became progressively impaired. Several days after a naso-orbital extirpation, both the patient's consciousness and orientation remained disturbed and CT scans showed homogeneous ring enhancement of a mass in the right frontal lobe that was associated with perifocal edema. As the diagnosis was a brain abscess, external drainage was provided by surgical treatment. After this surgery the patient's neurological deficits improved gradually and the patient was discharged when he became ambulatory. At 2 years postsurgically, no recurrence has been seen in follow-up CT scans. Rhinocerebral mucormycosis occurs in patients with diabetes mellitus and/or with some immunosupressive condition, these latter conditions causing a greater frequency of this disease. It thus is suggested that more aggressive attempts to achieve an earlier diagnosis and early, intensive therapy may reduce the incidence of a poor outcome. Different types of mucormycosis of the brain are also reviewed in this report and the diagnosis and management of such cases are discussed.

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Reported is a case of isolated right abducens nerve palsy, which appeared immediately after an operation to treat an unruptured internal carotid artery aneurysm. Rongeuring the roof of the superior orbital fissure and compression of its contents are thought to be a cause of this palsy. The abducens nerve runs medial to the trigeminal nerve in the cavernous sinus, after which it runs laterally to the annulus of Zinn. It can be very easily injured at this point by any compression from the lateral side. A reasonable extension when removing the lesser wing of the sphenoid bone is also discussed.

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We report 3 cases in which calcified epidural hematomas were found after neurosurgery and give the details below. Case I underwent ventriculo-arterial shunt at the age of 6 for congenital hydrocephalus. More than 10 years later, a calcified epidural hematoma on the left side and a calcified chronic subdural hematoma on the right were found. In case 2, a patient with holoprosencephaly and marked hydrocephalus, an acute epidural hematoma that had occurred after placement of a ventriculo-peritoneal shunt was found to have calcified. Case 3, a patient who underwent surgery for an intraventricular glioma, developed a calcified epidural hematoma of the contralateral side to where a craniotomy had been performed more than 10 years earlier. The development of a calcified chronic subdural hematoma after decompressive intracranial surgery is a well known occurrence, but the fact that a calcified epidural hematoma can also develop after decompressive surgery should also be kept in mind and should receive due attention.

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An adult ventriculo-atrial shunt usally requires many manipulations to insert an atrial tube into the internal jugular vein. Therefore, a new method catheterizing the atrial tube into the right atrium has been attempted. Following percutaneous insertion of the sheath introducer (8 Fr) into the internal jugular vein, the atrial tube was catheterized using a straight guide wire into the right atrium with the sheath-introducer through fluoroscopy. The authors believe this new technique can minimize operative procedures, and can be accomplished easily and accurately.

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