To validate the corticospinal tract (CST) and arcuate fasciculus (AF) illustrated by diffusion tensor imaging (DTI), we used CST- and AF-tractography integrated neuronavigation and monopolar and bipolar direct fiber stimulation. Methods: Forty seven patients with brain lesions adjacent to the CST and AF were studied. During lesion resection, direct fiber stimulation was applied to the CST and AF to elicit motor responses (fiber-MEP) and the impairment of language-related functions to identify the CST and AF. The minimum distance between the resection border and illustrated CST was measured on postoperative images. Results: Direct fiber stimulation demonstrated that CST- and AF-tractography accurately reflected anatomical CST functioning. The cortical stimulation to the gyrus, including the language-fMRI activation, evoked speech arrest, while the subcortical stimulation close to the AF reproducibly caused "paranomia" without speech arrest. There were strong correlations between stimulus intensity for the fiber-MEP and the distance between eloquent fibers and the stimulus points. The convergent calculation formulated 1.8mA as the electrical threshold of CST for the fiber-MEP, which was much smaller than that of the hand motor area. Validated tractography demonstrated the mean distance and intersection angle between CST and AF were 5mm and 107°, respectively. In addition, the anisotropic diffusion-weighted image (ADWI) and CST-tractography clearly indicated the locations of the primary motor area (PMA) and the central sulcus and well reflected the anatomical characteristics of the corticospinal tract in the human brain. Discussion: DTI-based tractography is a reliable way to map the white matter connections in the entire brain in clinical and basic neuroscience. By combining these techniques, investigating the cortico-subcortical connections in the human central nervous system could contribute to elucidating the neural networks of the human brain and shed light on higher brain functions.

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Surgical resection of opercular gliomas imposes a major challenge for neurosurgeons due to their close vicinity to functionaly important language and motor areas. Recent advances in intraoperative functional brain mapping and neuronavigation systems can help reduce neurological complications and maximize surgical resection of tumors located in the frontoparietal opercular region. The authors report their experience with opercular gliomas, with an emphasis on preservation of the subcortical function. Potential methods used to avoid damaging the subcortical motor pathway include widely splitting the sylvian fissure and identifying early the upper limiting sulcus of insula and the middle cerebral artery-M2 branches to define the inferior resection plane, removing the tumor by "en bloc" fashion through the preparation of the sulci, and dissecting the medial aspect of the tumor in a superior to inferior direction along the corticospinal fiber tract.

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In skull base surgery, knowledge of the techniques used to avoid postoperative cerebrospinal fluid (CSF) leakage is important. CSF leakage can lead to critical infection problems such as meningitis and extradural abscess. It is important to avoid CSF leakage into the subcutaneous surgical cavity and other areas, e.g. rhinorrhea. If subcutaneous fluid collects in spaces, including drilled air cells, then the risk of infection increases. Risks of CSF leakage are classified as dural level and extradural level. Different approaches to the skull base also have different risk levels. We emphasize four techniques for avoiding postoperative CSF leakage: watertight dural closure, filling of dead spaces, external compression, and lumbar drainage. For some surgical approaches, not all of these techniques can be used. In these cases, it is necessary to ensure that the appropriate technique is effectively applied. Skull base surgery is becoming a standard neurosurgical technique. The surgeon who is permitted to open the skull base must be able to close it and reconstruct it reliably. The skull base surgeon must have a knowledge and mastery of the techniques of skull base reconstruction, and must always be aware of the need to prevent CSF leakage.

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There is a potential risk of sacrificing the cortical vein during neurosurgical operations, particularly in the interhemispheric or subtemporal approach. An impaired cortical vein might cause cerebral venous circulatory disturbances resulting in postoperative venous infarction. In this article, we reviewed the clinical features of venous infarction from our experiences, and describe how to prevent venous problems associated with the neurosurgery. We have encountered 8 cases (0.3%) with symptomatic postoperative venous infarction during the past 5 years. We found 2 types: severe onset (severe type; 5 cases) and gradual onset (mild type; 3 cases). The former needs immediate treatment from the intraoperative period onward, and the prevention of the ongoing venous thrombosis is essential in the latter. In order to prevent postoperative venous complications, we should take into account (1) the selection of surgical approach considering the cerebral venous system (especially dangerous venous structures), (2) the techniques required to preserve veins during the operation, (4) a safe method for vein the sacrifice, and (3) the treatment of postoperative venous infarction, in various operative strategies.

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Development of the cerebral veins does not parallel that of the cerebral arteries. Paired primary head veins that develop at both sides of the neural tube collect blood from the primitive dural plexuses. After the closure of the neural tube, initial choroidal drainage to the median vein of prosencephalon is transferred to the paired internal cerebral veins and the great vein of Galen. Dorsolateral enlargement of the cerebrum requires development of the tentorium cerebelli. The tentorial sinus within the tentorium initially receives blood transversely from the telencephalon, diencephalon, and mesencephalon, and transfers its role to the longitudinally formed basal vein (basal vein capture). Superficial cerebral veins (Sylvian, Trolard, and Labbe) establish enough cortical anastomoses to each other. Subsequently, the superficial Sylvian vein draining to the tentorial sinus is captured to the cavernous sinus to a variable degree following distal regression of the tentorial sinus. Variations of drainage patterns of the basal vein, cavernous sinus capture, collateral at the base of the brain (Trolard circle), and the development of transcerebral medullary veins provide various clinical pictures in cerebral venous pathologies. An understanding of the functional anatomy of the cerebral veins is essential for the interpretation of the pathophysiology of the cerebral venous diseases and for administering safer treatment.

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Study Design: A retrospective study of consecutive patients. Objective: To investigate the efficacy of sacroiliac joint block on sacroiliac joint pain as a treatment and a diagnostic procedure, and to define its coexistence with other lumbar diseases. Background: Sacroiliac joint (SJ) pain is a challenging condition accounting for 10〜20% cases of chronic low back pain. As SJ pain dose not have specific neuroimaging findings, diagnosis is typically made by SJ block. However, the efficacy of SJ block has not been fully reported. In addition, there are a few reports of SJ pain coexisting with other lumbar diseases. Method: SJ block was performed on 72 patients with suspected SJ pain as determined by neurological findings. SJ blocks were applied in the upper, middle and lower parts of the SJ with 0.2% Ropivacaine. The visual analogue scale (VAS) was recorded before and after the procedure. Coexisting lumbar diseases and past lumbar surgeries were also recorded by review of the patients medical records. Results: The average age of 72 patients was 62.1 years old (range 21〜88 years old). There were 39 males and 33 females. Forty-six patients (63.9%) had pain relief with a 52.4% improvement on VAS. SJ pain accounted for 14.1% of all patients with low back pain. Thirty-six patients (78.3%) had other lumbar diseases. Conclusions: SJ pain should be considered as one factor of chronic low back pain in patients with lumbar disease. SJ block is useful not only as a diagnostic but also as a treatment option.

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OBJECT: The aim of the present study is to assess whether a new technique of surgical microscope-based indocyanine green (ICG) videoangiography (VAG) to assess cortical blood flow is suitable for intraoperative confirmation of successful aneurysm clipping. CASE REPORT: We used a Carl Zeiss Surgical Microscope OPMI^[○!R] Pentero INFRARED 800 and FLOW 800 system (Carl Zeiss Co., Tokyo, Japan), in the case of a 61-year-old woman with an unruptured left middle cerebral artery aneurysm. FLOW 800 is a new tool to analyze video data subsequent its acquisition with ICGVAG. Images were excellent and enabled a real-time surgical assessment if the structures of interest were visible to the surgeon's eye under the microscope, including vessels, perforating arteries, or residual aneurysm neck. Blood flow intensity data were revealed relative to alterations in fluorescence intensity. CONCLUSIONS: ICGVAG and the FLOW 800 system provide simple, reliable, real-time and rapid intraoperative assessment of relative cortical perfusion. This technique may help to improve the quality of neurosurgical procedures.

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