[Carotid Artery Stenting in a Tortuous Artery Results:A Case Report].

BACKGROUND: After carotid artery stenting(CAS)in a tortuous artery, the geometrics and elongation of the carotid artery sometimes change. It is not clear whether these changes induce post stent re-stenosis. We report a case of re-stenosis that occurred two years after CAS in a tortuous artery that required carotid endarterectomy with removal of the stent. CASE PRESENTATION: CAS was performed on a 78-year-old male who presented with symptoms of severe stenosis of a tortuous internal carotid artery. Eighteen months after stenting, the echogram revealed moderate stenosis at the distal end of the stent. Six months later, this developed into severe stenosis. Carotid angiography showed that the end of the stent was touching the wall of the internal carotid artery, and blood was passing through the stent wall. A re-CAS was difficult to perform;hence carotid endarterectomy with removal of the stent was performed successfully. He was discharged without any new neurological deficits. CONCLUSION: CAS on a tortuous carotid artery sometimes results in changes to the geometry and elongation of the artery. Potentially, this can lead to changes in the positional relationship between the stent and the artery, alteration of the wall shear stress and re-stenosis. Careful follow-up is needed after CAS on a tortuous artery.

A non-adhesive solid-gel electrode for a non-invasive brain-machine interface.

A non-invasive brain-machine interface (BMI) or brain-computer interface is a technology for helping individuals with disabilities and utilizes neurophysiological signals from the brain to control external machines or computers without requiring surgery. However, when applying electroencephalography (EEG) methodology, users must place EEG electrodes on the scalp each time, and the development of easy-to-use electrodes for clinical use is required. In this study, we developed a conductive non-adhesive solid-gel electrode for practical non-invasive BMIs. We performed basic material testing, including examining the volume resistivity, viscoelasticity, and moisture-retention properties of the solid-gel. Then, we compared the performance of the solid-gel, a conventional paste, and an in-house metal-pin-based electrode using impedance measurements and P300-BMI testing. The solid-gel was observed to be conductive (volume resistivity 13.2 Ωcm) and soft (complex modulus 105.4 kPa), and it remained wet for a prolonged period (>10 h) in a dry environment. Impedance measurements revealed that the impedance of the solid-gel-based and conventional paste-based electrodes was superior to that of the pin-based electrode. The EEG measurement suggested that the signals obtained with the solid-gel electrode were comparable to those with the conventional paste-based electrode. Moreover, the P300-BMI study suggested that systems using the solid-gel or pin-based electrodes were effective. One of the advantages of the solid-gel is that it does not require cleaning after use, whereas the conventional paste adheres to the hair, which requires washing. Furthermore, the solid-gel electrode was not painful compared with a metal-pin electrode. Taken together, the results suggest that the solid-gel electrode worked well for practical BMIs and could be useful for bedridden patients such as those with amyotrophic lateral sclerosis.