The advantages of carotid sonography are its capabilities to obtain morphological information such as stenosis or ulceration and to permit the speculation of tissue characterization. Morphological aspect ・ Our data suggest that the degree of stenosis from color coded Dopper imaging tends to be underestimated as compared with that estimated by angiography, because the sonography from color-coded Doppler goes over the artery wall, especially in severe stenosis. However, the accuracy of identifying carotid artery stenosis by carotid sonography is above 90% by combined use of the criteria from peak systolic velocity. Tissue characterization: The plaques are classified into echolucent, echogenic or hyperechoic from the echogenecity, and into homogeneous or heterogeneous from its context. Echolucent plaque reflects hemorrhage or atheroma, echogenic plaque reflects fibrosis, and hyperechoic reflects calcification. The classification should be based on the quantitative analysis, because the judgment of echogenecity is influenced by the instruments used and used sonographers themselves.

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Choosing the best treatment for intracranial unruptured aneurysms (UA) is one of the issues facing neurosurgions field. Although the natural history of UA is still uncertain, the surgical results for UA should be clarified to determine the best treatment for UA. In this article, surgical results for UA were reviewed, and they suggested that surgical risk of less than 3-5% might be expected for UA smaller than 10 mm in anterior circulation. But we should pay more attention to cognitive impairment after UA surgery to evaluate the complications minutely. To prevent surgical complications, intraoperative monitoring, e.g. motor evoked potentials, endoscopy assistance and intraoperative angiography, were expected to be beneficial, and a combination of surgery and endovascular treatment might be one of the solution for patients harboring UA.

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Based on data from Akita Stroke Register and Research Institute for Brain and Blood Vessels〜Akita, we evaluated the prognosis of patients with ruptured cerebral aneurysms, the factors affecting their prognosis, and the effects of aging on prognosis. The case fatality rate of patients with subarachnoid hemorrhage (SAH) 30 days post ictus is 29% which is worse than that of hypertensive intracerebral hemorrhage and cerebral infarction. Case fatality rate and long-term prognosis were associated with age of the SAH patients at onset. Since neurological condition following onset correlates with prognosis of SAH, mortality and disability are higher in poor-grade SAH patients. Thus, because SAH occurs more frequently in patients in their late 60's and older, we predict that the numbers of patients with poor-grade SAH and a poor prognosis will increase in an aging Japanese society.

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Unruptured cerebral aneurysm study in Japan (UCAS Japan) is conducted to clarify natural course and treatment risks of unruptured cerebral aneurysms (UCA), and build national data bank. This is a prospective cohort study and enrolled patients are cases with newly diagnosed UCA after Jan. 1, 2001. Data of all patients with UCA, either treated or observed, are stored into the head-quarter computer through internet registration. All cases are scheduled to have periodic follow-up at 3 months, 12 months and 36 months after diagnosis. As of April 2003, 4,940 patients (6,080 aneurysms) with newly diagnosed UCA were registered from 395 institutions. So far, there is a difference in registry status between geographic locations in Japan. Male-female ratio was 1: 2 and median age of patients was 64 years old. Size of aneurysm ranged 3〜45 mm (median 5 mm). The most frequent reason for imaging, which leaded diagnosis of UCA, was ill-defined symptoms such as headache or dizziness. Multiple aneurysms were found in 17% of cases and 96% of aneurysms were saccular ones. At the first registration, craniotomy was indicated in 34% and endovascular treatment in 5% of cases. Three months follow-up were reported in 4,077 cases and 12 months report in 2,285 cases. Treatment was performed in 1,743 cases with 2,007 aneurysms. So far, data of 4,090 person-year has been constructed. We are planning to call for further patient's enrollment and conform reliable data source to direct future management of UCA.

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[in Japanese]

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Anterior decompression and fusion is the gold standard surgical technique for cervical spondylosis. In this paper, we mainly described surgical tips for the anterior approach using titanium cages that were utilized in our institute. A conventional anterior cervical approach is as follows : A transverse skin incision is performed. Sharp dissection within a triangle of sternocleidomastoid muscle and omohyoid muscle is accomplished. The longus colli muscles are dissected bilaterally by using bipolar cautery. Retractor blades are placed beneath the muscle. After removing the intervertebral disc, a high-speed diamond drill is used. Osteophytectomy is carried out with a curette. After removing the protruded disc and osteophyte, two titanium cages are inserted in parellel. Overall complications using the anterior approach for cervical spondylosis and OPLL is 4.7%. In this article, informed consent for treating cervical spondylosis is also described. We would like to stress that anterior interbody fusion using titanium cages is a highly useful surgical procedure for treating cervical spondylosis.

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Lumbar spinal degenerative disorders were considered from the point of view of minimally invasive surgery. In the present paper, tailored operations, lumbar surgery under lumbar anesthesia and lumbar fixation were all discussed. To perform minimally invasive lumbar surgery, an accurate pathological point must be identified depending upon meticulous neurological examinations and a combination of several radiological examinations. The history of surgical procedures for lumbar canal stenosis to date was described. Most lumbar surgeries can be safely performed under the lumbar anesthesia. Owing to this anesthesia, surgical treatment can be done even if the patients have serious systemic complications such as cardiac or lung disorders. Lumbar fixation procedures are essentially invasive. Nerve root injury or paraspinal muscle damage is sometimes encountered in lumbar fixation surgery. Meticulous consideration about the indication and fixative procedures must be taken in order to perform minimally invasive lumbar surgery.

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We performed this study to elucidate whether or not the extent of the bypass flow through superficial temporal artery-to-middle cerebral artery (STA-MCA) anastomosis could be indirectly estimated by measuring the blood flow velocity in the STA using duplex ultrasonography. We analyzed 32 patients (35 sides) who underwent STA-MCA bypass surgery for occlusive cerebrovascular disease. The flow velocities of the STA were measured by ultrasonography. For the patients who underwent the surgery unilaterally, the flow velocity ratios of the operated side to the contralateral side were calculated. The correlation between these flow velocity parameters and the extent of the bypass flow, which was graded based on the findings of cerebral angiography, was investigated. Both the affected STA flow velocity and the STA flow velocity ratio, particularly those in end-diastole, increased in patients with more extensive bypass flow. In patients with extensive, moderate and poor bypass flow, the end-diastolic flow velocities (EDV) of the operated STA were 32.0±17.4, 24.9±9.5 and 13.5±7.5 (cm/sec), respectively and the EDV ratios of the STA were 3.4±0.7, 2.2±0.5 and 1.3±0.4, respectively. The optimal threshold value of the EDV ratio of STA for the extensive group was 2.7 while that for the poor group was 1.6. With the obtained values, the sensitivity and specificity were 88.9% and 91.4% for the extensive group, and 95.8% and 95.0% for the poor group, respectively. The blood flow velocity in the operated STA appeared to be a highly sensitive parameter for predicting the extent of the bypass flow in patients undergoing STA-MCA anastomosis.

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A case of diploic epidermoid cyst in the left parietal bone is reported. A 33-year-old woman visited our hospital with a history of headache. A skull x-ray showed an osteolytic focal lesion in the left parietal bone. Computed tomography (CT) revealed a well-demarcated hypodense diploic mass and the bony destruction of both inner and outer tables. Magnetic resonance imaging (MRI) also revealed a mass with low signal intensity on the Tl weighted image and high signal intensity on the T2 weighted image, respectively. MRI with a Gadolinium-based contrast medium showed negative enhancement, essentially in the tumor, and dura mater attached directly to the tumor. To know the details of the shape and the size of the craniectomy in advance, a three-dimensional plaster-cast model of the skull that had the same form as the host bone was made before surgery using a computer-aided design in accordance with the patient's three-dimensional CT image data. At surgery, the tumor didn't show any adherence to the dura mater or even to periostper se. The diploic tumor was totally extirpated including the adjacent bone of the skull, and additionally a cranioplasty using hydroxyapatite ceramic was performed concurrently. A piece of hydroxyapatite ceramic was successfully implanted in the site of the bone defect and some trimming was performed using a device for drilling bone. In the report, we confirmed that a preoperatively designed ceramic model is crucial in the performance of cranioplastic surgery, particularly in the treatment of a cranial bone defect using hydroxyapatite ceramic.

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