Most cases of optic hypothalamic pilocytic astrocytoma (OHPA) develop during childhood, so few cases of histologically verified OHPA have been described in adolescents and young adults (AYA). To elucidate the clinical features of OHPA with histological verification in AYA, we reviewed the clinical and radiological finding of OHPA treated at our institute from January 1997 and July 2017. AYA are aged between 15 and 39 years. The clinical courses of 11 AYA patients with optic hypothalamic glioma (OHG) without neurofibromatosis type 1 were retrospectively reviewed. About six patients were diagnosed in childhood and followed up after 15 years of age, and five patients developed OHPA during AYA. Histological diagnosis, verified at initial presentation or recurrence, was pilocytic astrocytoma in 10 and pilomyxoid astrocytoma in one. After initial treatment including debulking surgery and/or chemotherapy, tumor progression occurred 16 times in seven patients as cyst formation, tumor growth, and intratumoral hemorrhage. Five of 10 patients suffered deterioration of visual function during AYA. One of 10 cases had endocrinopathies requiring hormone replacement at last follow-up examination. In conclusion, histological diagnoses of OHG before and in AYA were pilocytic astrocytoma or pilomyxoid astrocytoma. Both pediatric and AYA-onset OHPA demonstrate high incidences of tumor progression and visual dysfunctions in AYA, so that long-term follow up is essential after the completion of treatment for pediatric and AYA-onset OHPA. The optimal timing of debulking surgery and radiation therapy should be established to achieve the long-term tumor control and to preserve the visual function.

Mechanical thrombectomy using a retrograde approach is performed for tandem occlusion of the internal carotid artery (ICA). In our patient, a guiding catheter was easily passed by the stenosed lesion despite severe stenosis at the ICA origin. Therefore, we aimed to recanalize the occlusion of the terminal ICA without angioplasty for the stenosed lesion. When contrast was injected, a massive extravasation of contrast from the C2 portion of the ICA was observed. It was speculated that the bleeding was caused by rupture of an aneurysm at that site due to increased intra-arterial pressure caused by the contrast injection to a blind alley, which was created by a wedged guiding catheter at severe stenosis at the ICA origin and the occlusion of the terminal ICA. Our simulation experiment using a silicon vascular model in this situation demonstrated that the elevation of intra-arterial pressure in such blind alley reached over 50, 100, and 200 mmHg by injection of contrast from a microcatheter, a 4-Fr inner catheter, and a 9-Fr balloon-guiding catheter, respectively. When a retrograde approach is planned for tandem occlusion of the ICA, even when the proximal lesion is easily passed, prior angioplasty for the proximal lesion should be considered to avoid wedging by catheter.

Carotid artery stenosis is elicited by atherosclerosis and is the main cause of cerebral thrombosis. Flow-mediated endothelial vasodilation (FMD) can be measured noninvasively to assess vascular endothelial function related to atherosclerosis. The pulse wave velocity (PWV) is used to evaluate the vascular media involved in atherosclerosis. We investigated the relationship between these measurements in 75 consecutive patients with atherosclerotic cerebral thrombosis. They were assigned to three equal groups based on the severity of carotid artery stenosis on ultrasonograms. Group 1 had no stenosis, group 2 manifested moderate stenosis (<60%), and group 3 presented with severe stenosis (≥60%). We compared the FMD and PWV among the three groups. The PWV was significantly lower in group 1 than the other two groups. The FMD was significantly lower in group 3; it was significantly lower in group 2 than group 1. There was an inverse correlation between the FMD and the severity of carotid artery stenosis. Our findings show that for assessing the severity of carotid artery stenosis, the FMD is more useful than the PWV.

The nasal cavity is the exclusive surgical corridor for endoscopic endonasal surgery; however, it is sometimes too narrow to allow extensive surgical maneuvering. Here we show the technique of submucosal inferior turbinectomy (SIT) to widen this surgical corridor. Its effectiveness is evaluated quantitatively by comparing pre- and intraoperative magnetic resonance images. Between March 2015 and October 2018, we performed endoscopic endonasal resection of 57 skull base tumors with 3T intraoperative magnetic resonance imaging (iMRI). Among these resections, cases with previous endonasal surgery and cases for which the iMRI did not cover the entire nasal cavity were excluded. Finally, six cases with and 19 cases without SIT were included in the subsequent retrospective analysis. We measured the dimensions of the narrowest area in inferior nasal cavity on pre- and intraoperative coronal plane gadolinium (Gd)-enhanced T1-weighted MR images using dedicated software, and compared them. The incidence rates of postoperative nasal complaints at outpatient clinics were also compared. Considerable widening of the inferior nasal cavity could be achieved with the SIT, which was statistically significant compared with those without the SIT (111.1 ± 56.5% vs. 39.4 ± 59.4%, respectively; P = 0.0093). In terms of the incidence rate of postoperative nasal complaints at 6 months, there was no statistical difference between the groups (33.3% vs. 15.8%, respectively; P = 0.35). SIT is effective for widening the surgical corridor while keeping nasal function and is especially helpful for lower clivus and laterally extended skull base lesions.

Biomechanical analysis was performed to evaluate the effectiveness of mastering ukemi in preventing severe head injury in judo. One judo expert (tori) threw another judo expert (uke) with a skilled break-fall (ukemi) four times. We obtained kinematic data of uke with a digital video camera. Both translational and rotational accelerations were measured with a six-degree-of-freedom sensor affixed to uke’s forehead. When Osoto-gari was performed, uke fell backward and his arm made contact with the tatami; the translational and rotational accelerations rose to peak values. The peak resultant translational and rotational accelerations were respectively 10.3 ± 1.6 G and 679.4 ± 173.6 rad/s² (mean ± standard deviation). Furthermore, when comparing the values obtained for the judo experts with those obtained using an anthropomorphic test device (ATD: the POLAR dummy) that did not perform ukemi, both the peak resultant translational (P = 0.021) and rotational (P = 0.021) accelerations of uke were significantly lower than those for the ATD, whose head struck the tatami. Additionally, there was no significant difference among the three axis directions for either translational (a_x: 7.4 ± 0.2, a_y: 8.5 ± 2.1, a_z: 7.2 ± 0.8 G) or rotational (α_x: 576.7 ± 132.7, α_y: 401.0 ± 101.6, α_z: 487.8 ± 66.6 rad/s²) acceleration. We confirmed that performing correct ukemi prevented the elevation of head acceleration by avoiding head contact with the tatami when a judoka is thrown by Osoto-gari. Judoka should therefore undertake intensive practice after they have acquired ukemi skills.

Handling surgical microscopes with one hand requires force, especially when gripping the operating handle (OH) to swing the optic axis toward the surgeon and when moving it laterally or medially. These physical issues may be attributable to the non-ergonomic handling of the OH. To optimize the ease of OH handling, we applied ergonomic criteria to the positioning of the OH, i.e. holding the OH at as little ulnar deviation as possible and at abduction to strengthen the grip and ease arm rotation. Of eight male surgeons holding the OH of a mechanically counterbalanced surgical microscope, the OPMI Neuro/NC4 (Carl Zeiss AG), in ergonomics-based positions, six experienced reduced fatigue in the upper extremity. All reported that their hold on the microscope was firm when it unexpectedly became unbalanced. Ergonomics-based OH positioning, i.e. placing the involved muscles in the optimal length-tension relationship, may generate sufficient force for moving the microscope efficiently and reduce arm fatigue.