Tatsuya Seguchi

Description and first clinical application of AirWay Scope for tracheal intubation.

We have developed a novel airway apparatus, AirWay Scope, which we have used in the orotracheal intubation of 10 consecutive patients requiring general anesthesia before neurosurgical procedures. The characteristic shape of the introducer (INTLOCK), the tube guiding function and the sighting device of the AirWay Scope has possibility to facilitate tracheal intubation. Here, we report the first clinical application of this system and describe potential advantages of the apparatus.

Prediction of Functional Outcome in Acute Cerebral Hemorrhage Using Diffusion Tensor Imaging at 3T: A Prospective Study

BACKGROUND AND PURPOSE: Early evaluation of the pyramidal tract is a prerequisite in patients with intracerebral hemorrhage (ICH) in order to decide the optimal treatment or to assess appropriate rehabilitation. The aim of this study was to evaluate and predict the neuromotor and functional outcome of an ICH by using diffusion tensor imaging (DTI) in the acute phase. MATERIALS AND METHODS: Eighteen patients with a hemiparetic supratentorial ICH were prospectively studied with DTI within 2 days after onset. A region-of-interest-based analysis was performed for the fractional anisotropy (FA) of the pyramidal tract in the cerebral peduncles. The degree of paresis was assessed at day 0 and day 28 by paresis grading (PG). The functional outcome was evaluated by the modified Rankin Scale (mRS). RESULTS: The FA in the affected side was significantly lower compared with that of the unaffected side (P = .001) with the mean diffusivity remaining unchanged (P = .50). The ratio of the FA (rFA) in the affected side to the unaffected side was significantly correlated with the PG at day 0 and 28 and the mRS score at day 28 (P = .002, r = −0.674; P < .001, r = −0.767; and P = .002, r = −0.676). The rFA for the good and poor outcomes based on the PG was significantly different (P < .001). The cutoff point of the rFA for the good and poor outcomes was set at 0.85 (sensitivity, 100%, specificity, 100%). CONCLUSIONS: We conclude that DTI can evaluate the motor deficit quantitatively and may predict the functional outcome in patients with an ICH who were scanned within 2 days after the ICH onset.

Anatomical study of the trigeminal and facial cranial nerves with the aid of 3.0-tesla magnetic resonance imaging.

OBJECT Neuroimages often reveal that the trigeminal or facial nerve comes in contact with vessels but does not produce symptoms of trigeminal neuralgia (TN) or hemifacial spasm (HFS). The authors conducted this study to determine how often the trigeminal and facial nerves came in contact with vessels in individuals not suffering from TN or HFS. They also investigated the correlation between aging and the anatomical measurements of the trigeminal and facial nerves. METHODS Between November 2005 and August 2006, 220 nerves in 110 individuals (60 women and 50 men; mean age 55.1 years, range 19-85 years) who had undergone brain magnetic resonance (MR) imaging for other reasons were studied. The lengths, angles, ratio, and contact points were measured in each individual. A correlation between each parameter and age was statistically analyzed. RESULTS The mean (+/- standard deviation) length of the trigeminal nerve was 9.66 +/- 1.71 mm, the mean distance between the bilateral trigeminal nerves was 31.97 +/- 1.82 mm, and the mean angle between the trigeminal nerve and the midline was 9.71 +/- 5.83 degrees . The trigeminal nerve was significantly longer in older patients. Of 220 trigeminal nerves, 108 (49.0%; 51 women and 57 men) came in contact with vasculature. There was 1 contact point in 99 nerves (45%) and 2 contact points in 9 nerves (4.1%). Contact without deviation of the nerve was seen in 91 individuals (43 women and 48 men), and mild deviation was noted in 17 individuals (8 women and 9 men). There was no moderate or severe deviation in any individual in this series. The mean length of the facial nerve was 29.78 +/- 2.31 mm, the mean distance between the bilateral facial nerves was 28.65 +/- 2.22 mm, the angle between the nerve and midline was 69.68 +/- 5.84 degrees , and the vertical ratio at the porus acusticus was 0.467 +/- 0.169. Of all facial nerves, 173 (78.6%; 101 in women and 72 in men) came in contact with some vasculature. Contact without deviation was seen on 64 sides (in 37 women and 27 men), mild deviation on 98 sides (in 57 women and 41 men), and moderate deviation on 11 sides (in 7 women and 4 men). There was no severe deviation of the facial nerve in this series. The proximal length of the facial nerve, interval, angle, and ratio against the age were significantly shorter or smaller in the older individuals. CONCLUSIONS The findings in asymptomatic individuals in this study will help in deciding which findings observed on MR images may cause symptoms. In addition, the authors describe the variations of normal anatomy in older individuals. Knowledge of the normal anatomy helps to hone the diagnostic practices for microvascular decompression, which may increase the feasible results on such surgery.

Cerebral aneurysm clips in the 3-tesla magnetic field. Laboratory investigation.

OBJECT The aim of this study was to evaluate cerebral aneurysm clips, and to know in more detail the characteristics of currently available clips in the 3-T magnetic field. METHODS According to the protocol recommended by the American Society for Testing and Materials (ASTM), the authors conducted quantitative evaluation for displacement force and qualitative evaluation for torque in 52 aneurysm clips and 48 samples of raw materials in the 3-T environment. RESULTS The largest displacement force occurred near the bore opening, and the force was directed to the isocenter. Deflection angles of all objects in this study were within 45°. The translational force in the peripheral position in the bore was larger than that in the center, and the translational force in the magnetic field was proportional to the weight of the objects. The proportion coefficients varied depending on the metallic materials. In the titanium alloy, the deflection angle was also detected to be approximately 2°, although no response was observed in titanium in a previous report. This behavior was similar to that of the Elgiloy and Phynox materials in the 1.5-T environment. No difference was observed among the groups of shapes (straight, bent, and fenestrated). The amount of torque that occurred was dependent on the clips or materials loop and bent shape. The torque on the titanium was perpendicular to the torque on the other materials (which was perpendicular to the magnetic field). CONCLUSIONS Care must be taken with patients near the bore opening while moving them to the center of the magnets bore on the MR imaging table. Although all the clips examined in this study met the ASTM requirements, the titanium alloy clips are preferable in the 3-T environment for safetys sake. Suitably sized clips should be selected for the aneurysm size, because the translational force increases proportionally to the objects weight.

Overdrainage of cerebrospinal fluid caused by detachment of the pressure control cam in a programmable valve after 3-tesla magnetic resonance imaging

The authors report a rare case of overdrainage of the CSF caused by the malfunction of a Codman-Hakim programmable valve (CHPV) following a 3-T MR imaging procedure. Nine years ago this 72-year-old woman underwent ventriculoperitoneal shunt placement with a CHPV system for hydrocephalus due to subarachnoid hemorrhage. The postoperative course was uneventful and the system functioned well. A radiograph obtained immediately after 3-T MR imaging revealed that the pressure control cam in the valve system was detached from the base plate. Intracranial hypotension syndrome occurred several hours after the MR imaging study, and a CT scan revealed a decrease in ventricle size. A revision of the system promptly resolved the symptoms, and a postoperative CT scan revealed that the ventricle size was restored to normal. Examination of the extracted valve showed a Y-shaped crack in the plastic housing as well as detachment of the white marker and cam from the base plate. A reduction in the power of the flat spring to press the valve ball led to CSF overdrainage because of a loss of support by the cam. Because the patient had incurred no head injury during the day and radiographic studies of the system 5 years previously had shown detachment of the white marker, damage to the system might have been caused by a past impact. These facts may indicate that the antimagnetic performance of the system could have decreased due to a previous impact and that the strong magnetic force in a 3-T MR imaging environment might have caused detachment of the cam.

Local brain herniation after partial membranectomy for organized chronic subdural hematoma in an adult patient: Case report and review of the literature

Objective: Local brain herniation after removal of chronic subdural haematoma is extremely rare, especially in adult patients. This study reports a case of local brain herniation after partial membranectomy for organized chronic subdural haematoma. Case report: A 77-year-old man presented with dysarthria and dysphasia caused by local brain herniation of the right frontal lobe through a defect of the inner membrane. The herniated brain was detected by magnetic resonance (MR) imaging. The patient underwent a craniotomy to release the herniated and strangulated brain, which were consistent with the MR imaging findings. The patient recovered fully within 1 month after surgery. Conclusions: To date, five cases of brain herniation through the internal subdural membrane have been reported as complications of chronic subdural haematomas. All but one case occurred in the paediatric population. Urgent surgery should be performed, even if an adult patient suffers from local brain herniation, for preservation of brain function. This is the sixth reported case of brain herniation through a defect of the inner membrane and the second reported case in the adult population.

Investigation of radiofrequency-induced temperature elevation of aneurysm clips in a 3.0-tesla magnetic resonance environment.

OBJECTIVEBurn injuries associated with excessive heating of medical metallic devices have been reported, but a definite mechanism for magnetic resonance imaging-induced heating remains unresolved. The aim of this study is to evaluate temperature elevation of metallic wires, aneurysm clips, and clips attached to metallic wires under 3.0-T magnetic resonance imaging. METHODSThe temperature of the metallic wires, the aneurysm clips, and the clips attached to the metallic wires was measured with a fiber optic thermometer sensor system. RESULTSAlthough the specific absorption rate was less than that observed during standard use, the temperature rapidly increased in the metallic wire. Furthermore, temperature elevation was observed when the clips were attached to metallic wires. On the other hand, not all clips showed obvious temperature elevation when they were placed alone in a 3.0-T magnetic resonance imaging environment. CONCLUSIONAneurysm clips, when placed alone in a 3.0-T magnetic resonance imaging environment, are confirmed to be safe during temperature elevation.

Surgery for ventral intradural thoracic spinal tumors with a posterolateral transpedicular approach

BackgroundSurgery for ventrally seated thoracic tumors requires an anatomically specific approach that is distinct from cervical or lumbar spinal cord surgery as the narrower spinal canal of the thoracic spinal cord makes it sensitive to surgical procedures. However, reports describing this operative technique are few. To obtain a wide operative field and minimize thoracic spinal cord retraction, we employed a posterolateral transpedicular approach in ventral-located tumors and investigated the efficacy and limitations of this technique.MethodEighteen patients with lesions (meningioma or neurinoma) located in the ventral intradural thoracic region were surgically treated between 2009 and 2014. The relationship among the clinical outcome, tumor location, and postoperative spinal alignment was analyzed.ResultsPostoperative neurological function improved in all patients, namely those with meningioma (p = 0.012) and schwannoma (p = 0.018). One patient who underwent removal of two facet joints suffered a postoperative compression fracture. Removal of two facet joints and pedicles resulted in a worsening of spinal alignment (p = 0.03), while this was not the case for the removal of one facet joint and pedicle (p = 0.72).ConclusionsThis case series clarified the benefits of the posterolateral transpedicular approach for resection of ventral intradural extramedullary tumors. Removal of one pedicle and facet joint seems to be more beneficial.

Calcified ectopic TSH-secreting pituitary adenoma mimicking craniopharyngioma: a rare case report and literature review

Among pituitary adenomas, which are relatively common brain tumors, elements of ectopic, thyroid-stimulating hormone (TSH) secretion, and intratumoral calcification are unusual. Here, we present an extremely rare case of a calcified ectopic TSH-secreting pituitary adenoma arising from the pars tuberalis mimicking craniopharyngioma based on neuroimaging findings. To our knowledge, this is the first case report of calcified ectopic TSH-secreting pituitary adenoma without symptoms of excessive thyroid hormone secretion.

Long Segment Spinal Dural Cyst: A Case Report

BACKGROUND Spinal meningeal cysts are a rare benign disease that can cause myelopathy. In most cases, spinal meningeal cysts consist of an arachnoid membrane. To the best of our knowledge, few articles have report on intradural spinal meningeal cyst consisting of dura mater. CASE DESCRIPTION A 58-year-old man presented to our institute with aggravation of clumsy hands and dysesthesia of the feet. Magnetic resonance imaging of the entire spine revealed a cystic lesion compressing the spinal cord posteriorly. Cyst fenestration and placement of the cyst-subarachnoid shunt was performed via an anterior approach. Postoperatively, the histopathologic results revealed that the cyst wall consisted of a dura mater-like membrane. The patients symptoms resolved without the appearance of any new neurologic deficits. CONCLUSIONS The etiology of spinal meningeal cysts remains unclear. Spinal meningeal cysts consisting of dura mater (spinal dural cysts) are extremely rare. Treatment with only decompression with laminectomy causes enlargement of the dural cyst later. Cyst fenestration and placement of a cyst-subarachnoid shunt for the spinal dural cyst resulted in the resolution of myelopathy and cyst shrinkage.