Bio-Medical Materials and Engineering - Volume 31, issue 6

Authors: Miyata, Ryuji | Matsumoto, Shuji | Miura, Seiji | Kawamura, Kentaro | Uema, Tomohiro | Miyara, Kodai | Niibo, Ayana | Hoei, Takashi | Ogura, Tadashi | Shimodozono, Megumi

Article Type: Research Article

Abstract: BACKGROUND: Gait analysis, such as portable gait rhythmogram (PGR), provides objective information that helps in the quantitative evaluation of human locomotion. OBJECTIVE: The purpose of this study was to assess the reliability of PGR in post-stroke patients. METHODS: Two raters (A and B) examined 48 post-stroke patients. To assess intra-rater reliability, rater A tested subjects on three separate occasions (Days 1, 2, and 3). To assess inter-rater reliability, raters A and B independently tested participants on the same occasion (Day 3). RESULTS: There was no significant systematic bias between test occasions or raters. Intraclass …correlation coefficient values were 0.93–0.97 for intra-rater reliability at both the comfortable speed and maximum speed, and 0.97–0.98 (comfortable speed) and 0.97–0.99 (maximum speed) for inter-rater reliability. The standard error was 1.25–1.49 (comfortable speed) and 1.62–1.77 (maximum speed) for intra-rater investigation, and 1.04–1.32 (comfortable speed) and 0.91–1.26 (maximum speed) for inter-rater investigation. At the 90% confidence level, the minimum detectable change ranged from 2.9–4.1%, and the error of an individual’s score at a given time point ranged from ±2.1–2.9%. CONCLUSIONS: Based on this excellent reliability of the PGR in post-stroke patients, it can be recommended as a simple test of gait analysis in this population. Show more

Keywords: Acceleration, gait analysis, portable gait rhythmogram, reliability, stroke

DOI: 10.3233/BME-206007

Citation: Bio-Medical Materials and Engineering, vol. 31, no. 6, pp. 329-338, 2020

Authors: Kamangar, Sarfaraz | Anjum Badruddin, Irfan | Anqi, Ali E. | Ahamed Saleel, C. | Tirth, Vineet | Yunus Khan, T.M. | Anas Khan, M. | Mallick, Z. | Salman Ahmed, N.J.

Article Type: Research Article

Abstract: BACKGROUND: The left coronary artery commonly known as LCA gets divided into two branches, such as the left circumflex (LCX) and left anterior descending (LAD) at a particular angle. This angle is varies from person to person. The present computational study contributes remarkable expertise about the influence of this angle variation on the hemodynamic parameters in the presence of 80% area stenosis at the LAD branch. OBJECTIVE: This study aimed to compare the effect of the bifurcation angle on hemodynamic parameters in the left coronary artery with 80% stenosis. METHOD: Computational models of left coronary bifurcation …angles of 30°, 60°, 90°, 120° were developed to understand the flow behavior of left coronary artery branches. The 80% area stenosis (AS) is considered at the LAD branch immediate to bifurcation. RESULTS: Measurements of pressure, velocity and wall shear stress were carried out corresponding to various bifurcation angles. It was found that the drop-in pressure increases as the angle increases from narrow to wider. A slight elevation in the velocity at the stenosis was observed. In addition, the obtained results further reveal a recirculation region immediately after the plaque, which leads to more deposition of plaque in the flow obstructed area. It is known that the shear stress at the arterial wall across the stenosis increases as the angle of bifurcation increases from narrow to wider. CONCLUSIONS: The bifurcation of the left coronary artery and size of the stenosis have a notable impact on the pressure and wall shear stress. These two factors should be given due consideration by cardiologists to assess the complexity of stenosis in the LCA branches. Show more

Keywords: Wall shear stress, atherosclerosis, stenosis, hemodynamic

DOI: 10.3233/BME-201107

Citation: Bio-Medical Materials and Engineering, vol. 31, no. 6, pp. 339-349, 2020

Authors: Horii, Tsunehito | Tsujimoto, Hiroyuki | Kageyama, Susumu | Yoshida, Tetsuya | Kobayashi, Kenichi | Takamori, Hideki | Minato, Hiroshi | Ueda, Jo | Hagiwara, Akeo | Ichikawa, Hiroshi | Kawauchi, Akihiro

Article Type: Research Article

Abstract: BACKGROUND: To overcome the unfavorable issues associated with conventional anti-adhesive HA/CMC film, we developed an anti-adhesive thermally cross-linked gelatin film. OBJECTIVE: We tried to clarify the re-attachability of the film and the required properties concerning the film thickness, stiffness and anti-adhesion effect. METHODS: To determine the optimal thickness, 5 kinds of the thickness of gelatin film and the conventional film were analyzed by the tensile test, shearing test, buckling test and tissue injury test. Finally, using the optimal film thickness, we tried to clarify the anti-adhesion effect of the reattached film. RESULTS: The tensile …and shearing test showed gelatin films ≥30 μm thick had greater tensile strength and a smaller number of film fractures, than the conventional film. The buckling and tissue injury test showed gelatin films ≥60 μm thick had higher buckling strength and worse injury scores than the conventional film. The anti-adhesive effect of re-attached gelatin film using optimal thickness (30–40 μm) found the anti-adhesion score was significantly better than that of the control. CONCLUSIONS: Provided it has an optimal thickness, gelatin film can be reattached with enough physical strength not to tear, safety stiffness not to induce tissue injury, and a sufficient anti-adhesion effect. Show more

Keywords: Anti-adhesion, re-attachability, gelatin film, thermally cross-linked, tissue injury

DOI: 10.3233/BME-206009

Citation: Bio-Medical Materials and Engineering, vol. 31, no. 6, pp. 351-360, 2020

Authors: Hayashi-Sakai, Sachiko | Kobayashi, Taichi | Sakamoto, Makoto | Hayashi, Takafumi | Morise, Yusuke | Nikkuni, Yutaka | Takamura, Masaki | Sakai, Jun | Shimomura-Kuroki, Junko | Ike, Makiko | Nishiyama, Hideyoshi

Article Type: Research Article

Abstract: BACKGROUND: Lip closing functions have never been evaluated from the viewpoint of elastic properties. OBJECTIVES: The purpose of the present study was to investigate the behavior of the lower orbicularis oris muscle during a button-pull exercise to measure lip closing force and quantitatively evaluate its elastic properties using sonographic elastography. METHODS: Appropriate compression loads for elastography were randomly measured on one of three types of acoustic couplers on three examiners. Compression tests were performed on three types of acoustic couplers within the appropriate compression load. Using the acoustic coupler with the lowest elastic modulus, the strain …ratio of the lower orbicularis oris muscle during lip closing was measured, and elastography was performed on six males under tension loads of 0–8 N. RESULTS: The intraclass correlation coefficient (1, 3) for the tension load of 0 N was 0.81. Elastography showed that the strain ratio values increased significantly (p < 0.05) as the tension load increased. CONCLUSIONS: Combining the data obtained from lip closing test devices and sonographic elastography enabled the muscle performance to be evaluated objectively and accurately. Show more

Keywords: Lip closing function, lower orbicularis oris muscle, ultrasound, sonographic elastography, strain ratio, elasticity

DOI: 10.3233/BME-201101

Citation: Bio-Medical Materials and Engineering, vol. 31, no. 6, pp. 361-371, 2020

Authors: Shigematsu, Taiki | Otani, Tomohiro | Tomotake, Shotaro | Shiozaki, Shunya | Wada, Shigeo

Article Type: Research Article

Abstract: BACKGROUND: The braided stent is a widely accepted endovascular treatment device consisting of woven metal wires. One of the unsolved issues for the braided stent is the stent flattening phenomena when deployed into highly curved arteries. Although a recent computational study highlighted that the mechanical state of the stent inside the catheter before the deployment plays an essential role in causing stent flattening, there is no experimental observation for the stent inside the curved catheter. OBJECTIVE: We investigated braided stent shapes in curved catheter tubes with various curvatures by micro-computed tomography (CT). METHODS: A braided stent …was deployed into catheter tubes and set in rectangular cases with constant curvature. The three-dimensional shape of the stent was imaged by micro-CT, and its cross-sectional flatness was quantitatively assessed. RESULTS: Stent flattening occurred in cases of high curvatures of the outer side of the tube curvature, and the degree of flatness increased with increasing tube curvature. This demonstrates that stent flattening can be caused inside the highly curved catheter before deployment. CONCLUSIONS: This preliminary and first observational report provides new insight into the mechanism of stent flattening and emphasizes the importance of the geometrical and mechanical state of the stent inside the catheter. Show more

Keywords: Braided stent, stent flattening, micro-computed tomography (CT), endovascular treatment, cerebral aneurysm

DOI: 10.3233/BME-206011

Citation: Bio-Medical Materials and Engineering, vol. 31, no. 6, pp. 373-380, 2020