The authors evaluated the radiological examinations and surgical approaches used for far-lateral lumbar disc herniation. Between May 1995 and March 1999, 32 cases of farlateral lumbar disc herniation were surgically treated at our institution. As for the radiological examinations, plain CT scans played an important role in only two patients. In 17 patients, MRI showed decisive findings for the final diagnosis. On the MRI studies, not only a routine sagittal or axial view, but also a coronal view had to be performed to detect the far-lateral disc herniation. In addition to the routine CT-myelography and MRI study, a disco-CT scan was performed in 13 patients and root-graphy in 8 patients. To obtain correct diagnoses, meticulous neuroradiological examinations with detailed readings had to be performed. As for the surgical approaches, the medial approach was adopted in 19 patients, and the lateral approach in 13 patients. In the medial approach, it was easy to obtain surgical orientation. With this approach however, a stabilizing procedure has to be taken into consideration because the interarticular portion is iatrogenically destroyed. In the lateral approach the surgical orientation was dificult. Using this approach, postoperative instability did not occur. Finally, the points involved in making the diagnosis and surgical treatment for far-lateral lumbar disc herniation are discussed.

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We evaluated the cognitive outcome in 40 consecutive patients who underwent surgery for unruptured intracranial aneurysms affecting the anterior circulation in the Willis ring to ascertain whether or not these patients were completely cured without any neuropsychological deficit from the surgery. We examined patients using the mini mental state examinations(MMSE)and a kana recognition test before and 3 months after surgery. We also used a simplified dementia diagnostic scale based on the Hamamatsu method, which contains the MMSE and kana recognition test. Prognostic factors were analyzed using a logistic regression test. There were no mortality cases, however there were 2 transient morbidity cases(transient morbidity rate 5.0%). The postoperative neuropsychological status of 38 patients was the same as or improving on the patients preoperative status for both the MMSE and kana recognition tests. The postoperative MMSE score for 2 patients was significantly lower than the preoperative score, and one of them showed a deterioration in her neuropsychological status by the Hamamatsu method(cognitive morbidity rate 2.5〜5.0%). The other 3 patients showed transient disorientation for several weeks after surgery(transient cognitive morbidity rate 7.5%). Factors found to be significant in relation to permanent or transient impairmeht of cognitive function included an age over 70 years old(p<0.05), a subnormal score in the kana recognition test, a subnormal score in the Hamamatsu method, having ischemic cerebrovascular disease(p<0.10). These results indicated that cognitive functions, including frontal lobe function, should be carefully examined to make a favorable treatment plan for unruptured aneurysms.

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Selective amygdalohippocampectomy through the inferior temporal gyrus, transventricular approach, was performed in 44 cases with medically intractable medial temporal lobe epilepsy since 1990 at the National Utano Hospital. A follow-up evaluation(mean duration 57 months, ranged from 6 months to 131 momths)showed that 88.6%(39 cases)of patients were completely free of seizures(Engel class I), 9.1%(4 cases)were almost seizure free(class II)and 2.3%(1 case)had worthwhile improvement(class III). Major complications included transient psychological symptoms(14/44 ; 31.8%)and memory impairment(5/44 ; 11.4%). However, there was statistically significant increase in total and performance intelligent quotients. Our approach for selective amygdalohippocampectomy was presented and compared with other operative methods to show that our access to the hippocampus has little possibility to injure the anterior choroidal artery or optic radiation, and to open ambient cistern.

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Bleeding from scalp incisions during cranial surgery can be quite troublesome. We have developed a stugical technique for controlling bleeding in scalp incisions and have applied this technique in more than 500 cranial surgeries in the past 5 years. We herein report this technique because intraoperative blood loss was significantly reduced and the cosmetic results appeared to be excellent. After preparation of the scalp and an outline of the scalp incision are completed 0.5% xylocaine with epinephrine(1 : 100, 000)is subcutaneously injected along the incision line. The scalp incision is made down to the layer of the subcutaneous fascia containing fat tissue and just prior to the large scalp vessels and the galea aponeurosis as well, which leads to a slight bleeding from the cut surface of the scalp. Care is taken not to allow excessive cauterization on the cut surface in order to prevent hair loss around the scalp incision. The scalp vessels on the galea are exposed with a blunt dissection technique and are cauterized. The scalp incision is completed by making a separate incision in the galea. At the conclusion of surgery, the scalp is replaced and the galea can be tightly approximated with braided absorbable sutures. This procedure may be easily carried out because the margin of the galea to be sutured up has already been prepared in the opening procedure. Skin sutures are made in an everting fashion by using a blanket-type running suture. We retrospectively studied blood loss and the time elapsed for surgery in 35 unruptured cerebral aneurysm surgeries carried out by using a standard pterional approach in 33 patients. The total volume of blood loss in each surgery ranged from the minimum(estimated to be 20ml)to 240ml with an average of 74ml. The time elapsed for surgery ranged from 110 to 210 min(average 159 min). Both parameters were significantly reduced in comparison with the data obtained in the same surgeries performed in our institute before introducing the technique described above. Anesthetically, there was no hair loss around the scalp incision in all but one patient. Besides conserving blood and controlling bleeding, this technique shortens the total length of time needed for cranial surgeries.

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Pleomorphic xanthoastrocytoma(PXA)is a rare brain tumor which usually develops on the cerebral surface in young people and has a good prognosis. A rare case of solid PXA on the parietal lobe, found during examination for headache, is reported. A 33-year-old female was referred to our hospital because of a headache in the right parietal region. At 20 years of age, she received an antiepileptic drug over the course of 1 year because of general convulsions. A low density mass was found in the right parietal surface on CT. On enhanced MRI, a 4.5×2cm tumor with dural enhancement was heterogeneously enhanced. Right frontoparietal craniotomy was performed resulting in the tumor being diagnosed as an extraaxial tumor. The yellowish tumor did not adhere to the dura and protruded from the right parietal lobe. The tumor did not include any cyst. The protruding tumor drifted into the brain surface and was totally removed. Histologically, the tumor cells displayed marked pleomorphism and some giant cells were found. However, neither any necrosis nor mitosis were found. The tumor cells were positive in glial fibrillary acidic protein and S-100 stain. The labeling index of MIB-1 was low. The histological diagnosis was PXA. The patient was neurologically normal after surgery, and discharged without irradiation.

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Symptomatic hemorrhage from vestibular schwannoma is not common, although small hemorrhages and hemosiderin deposits are sometimes found in histological findings. In this article, a rare case of subarachnoid hem-orrhage from a vestibular schwannoma is reported. In addition, the patient has a sporadic ipSilateral tentorial meningioma. A 67-year-old female had noticed a left side hearing disturbance for 9 years. She noted the onset of a sudden severe headache and vomiting while shoveling snow. Plain CT on admission showed a local high-density lesion in the cerebellomedullary cistern, and compression of the 4th ventricle to the right side, which indicated the possible existence of a left cerebellopontine angle tumor. A sporadic tentorial meningioma was also revealed on enhanced CT and MRI. Both tumors were removed simultaneously via left suboccipital approach on day 13th after onset, As hemosiderin deposits on the arachnoid membrane and intratumoral hematoma in the vestibular schwannoma were identified, a subarachnoid hemorrhage from this tumor was diagnosed.

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Cerebral dissecting aneurysms have recently had special remark with the progress of neuroimaging. The causes of presenting neurological symptoms in vertebral artery(VA)dissecting aneurysms are considered mainly to be cerebral ischemia or subarachnoid hemorrhage. It is rare that both cerebral ischemia and subarachnoid hemorrhage occur in a short period. We present a case of a vertebral dissecting aneurysm initially associated with Wallenberg's syndrome caused by ischemic stroke and secondaiy subarachnoid hemorrhage. The patient was a 57-year-old female with complaints of severe occipitalgia, vertigo and vomiting while swimming. The next day some signs of Wallenberg's syndrome appeared. The patient was referred to our hospital and underwent cerebral angiography, which revealed the dissecting aneurysm originating from the distal side of the right VA-PICA junction. However, she also suffered from severe headache due to subarachnoid hemorrhage after the 11th day from the onset. We performed ligation of the right VA at the distal side of PICA. Repeated cerebral angiograms demonstrated an obstruction of the right VA from the extracranial portion without any signs of neurogical deficit. Considering these findings, the orifice of the dissecting aneurysm seemed to be located in the third portion of right VA. Swimming may precipitate the manifestation of symptoms due to VA dissecting aneurysms through minor neck injury.

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The case is a 53-year-old man with hypertrophic cranial pachymeningitis of the falx that showed interesting MR images. The patient was originally referred to our institute due to uncontrollable generalized seizure at the age of 51 years. MR images revealed a thickening falx with gadolinium(Gd)enhancement and an intra-axial abnormal Gdenhanced lesion in the frontal lobe. These 2 abnormal enhanced lesions were not connected to each other on MR images. Bifrontal craniotomy with total resection was performed. The results of histopathological examination revealed chronic inflammatory change and no neoplastic findings. The patient has not experienced any seizures after surgery. Discrimination of pachymeningitis from neoplastic disease and particularly from malignant disease was important for appropriate treatments in this case.

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We report a rare case of metastatic mixed pineocytoma/pineoblastoma, which appeared after long-term dormancy. This patient was initially admitted to our hospital because of severe headache and diplopia when he was 46 years old. A CT scan showed a calcified tumor in a pineal region with mild hydrocephalus. After Ommaya reservoir replacement, a biopsy through an infratentorial-supracerebellar approach failed to yield a definitive diagnosis. After local radiation therapy, the tumor decreased in size, and he was doing well without any symptoms. Ten years later, MR imaging showed a new mass lesion behind the medulla oblongata, which was subsequently removed. Histological examination demonstrated a mixed pineocytoma/pineoblastoma. Three courses of chemotherapy consisting of carboplatin and etoposide were administered, and no residual tumor or recurrence has been observed thereafter.

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