Development of an Evaluation System for Magnetic Resonance Imaging Based Three-Dimensional Modeling of a Transfemoral Prosthetic Socket Using Finite Elements

Recent technologies have suggested the utilization of three-dimensional (3D) printingtechnology to enhance the fabrication accuracy of prosthetics. Accordingly, simulations are used toobtain precise parameters for subject-specified prosthetic socket. This study proposes an evaluationsystem to measure the accuracy of a subject-specific 3D transfemoral residuum model duringthe interaction with the socket in conjunction with the application of finite element methods.The proposed system can be used in future validations of socket fabrication. The evaluation isbased on the measurement of the residuum’s soft tissue deformation inside two types of prostheticsockets. In comparison with other studies, the 3D models were constructed with magnetic resonanceimages (MRI) with the aid of computer-aided design (CAD) software. The measurement of soft tissuedeformation was conducted based on the measurement of the volumetric value of fat, muscle andskin in the pre- and post-donning phases. The result yielded a promising correlation coefficient valuebetween the simulation and the experiment in the soft tissue deformation evaluation. The relationof the muscle–fat ratio in the residuum is extremely important in the determination of the abilityof the prosthetic to deform. The environment during the socket fitting session was similar to thatdefined by the set boundary conditions in simulations. In view of the promising results of thisstudy, the evaluation system proposed herein is considered reliable and is envisaged to be used infuture research

Drug retention and discontinuation reasons between seven biologics in patients with rheumatoid arthritis -The ANSWER cohort study-

The purpose of this study was to evaluate the retention and discontinuation reasons of seven biological disease-modifying antirheumatic drugs (bDMARDs) in a real-world setting of patients with rheumatoid arthritis (RA). 1,037 treatment courses with bDMARDs from 2009 to 2016 [female, 81.8%; baseline age, 59.6 y; disease duration 7.8 y; rheumatoid factor positivity 81.5%; Disease Activity Score in 28 joints using erythrocyte sedimentation rate (DAS28-ESR), 4.4; concomitant prednisolone 43.5% and methotrexate 68.6%; Bio-naïve, 57.1%; abatacept (ABT), 21.3%; tocilizumab (TCZ), 20.7%; golimumab (GLM), 16.9%; etanercept (ETN), 13.6%; adalimumab (ADA), 11.1%; infliximab (IFX), 8.5%; certolizumab pegol (CZP), 7.9%] were included in this multi-center, retrospective study. Drug retention and discontinuation reasons at 36 months were estimated using the Kaplan-Meier method and adjusted by potent confounders using Cox proportional hazards modeling. As a result, 455 treatment courses (43.9%) were stopped, with 217 (20.9%) stopping due to inefficacy, 113 (10.9%) due to non-toxic reasons, 86 (8.3%) due to toxic adverse events, and 39 (3.8%) due to remission. Drug retention rates in the adjusted model were as follows: total retention (ABT, 60.7%; ADA, 32.7%; CZP, 43.3%; ETN, 51.9%; GLM, 45.4%; IFX, 31.1%; and TCZ, 59.2%; P < 0.001); inefficacy (ABT, 81.4%; ADA, 65.7%; CZP, 60.7%; ETN, 71.3%; GLM, 68.5%; IFX, 65.0%; and TCZ, 81.4%; P = 0.015), toxic adverse events (ABT, 89.8%; ADA, 80.5%; CZP, 83.9%; ETN, 89.2%; GLM, 85.5%; IFX, 75.6%; and TCZ, 77.2%; P = 0.50), and remission (ABT, 95.5%; ADA, 88.1%; CZP, 91.1%; ETN, 97.5%; GLM, 94.7%; IFX, 86.4%; and TCZ, 98.4%; P < 0.001). In the treatment of RA, ABT and TCZ showed higher overall retention, and TCZ showed lower inefficacy compared to IFX, while IFX showed higher discontinuation due to remission compared to ABT, ETN, GLM, and TCZ in adjusted modeling.Ebina K., Hashimoto M., Yamamoto W., et al. (2018) Drug retention and discontinuation reasons between seven biologics in patients with rheumatoid arthritis -The ANSWER cohort study-. PLoS ONE 13(3): e0194130. doi: 10.1371/journal.pone.0194130

EXPERIMENTAL CONSIDERATION ON THE FACTORS WHICH CAUSES VARIATION IN FITTING SURFACE EMG INTERFACE

Electricalmyography or myoelectric signal is used to voluntarily control current commercial electric prosthetic modules in the upper limb prosthetics. One of the technological questions that are rarely discussed is the assessment of fitting or tuning the EMG sensors to gain suitable and robust control signal. Such methods are mostly neglected by laboratory researchers because workable signals can be obtained through trial and error for short-period experiments, and for clinical use, humans are more adaptable then machines. However, the reliability of the interface is a key feature for promising everyday use of a device, and therefore, an assessment strategy and a design method for assembling a durable myoelectrically controlled prosthetic arm is expected. Furthermore, quantitative data is advisable for product design which requires robustness in long life use. In this paper, we applied a Quality Engineering technique [1] to investigate the factors in installing EMG sensors for generating activation (ON/OFF) control signal. Eight influential factors on fitting surface EMG electrodes for prosthetic hand control were selected based on heuristics and De Luca’s relation diagram [2], and a multifactor experiment was conducted as a pilot test on a single ablebodied subject

Networked Multimodal Sensor Control of Powered 2-DOF Wrist and Hand

A prosthetic limb control system to operate powered 2-DOF wrist and 1-DOF hand with environmental information, myoelectric signal, and forearm posture signal is composed and evaluated. Our concept model on fusing biosignal and environmental information for easier manipulation with upper limb prosthesis is assembled utilizing networking software and prosthetic component interlink platform. The target is to enhance the controllability of the powered wrist’s orientation by processing the information to derive the joint movement in a physiologically appropriate manner. We applied a manipulative skill model of prehension which is constrained by forearm properties, grasping object properties, and task. The myoelectric and forearm posture sensor signals were combined with the work plane posture and the operation mode for grasping object properties. To verify the reduction of the operational load with the proposed method, we conducted 2 performance tests: system performance test to identify the powered 2-DOF wrist’s tracking performance and user operation tests. From the system performance experiment, the fusion control was confirmed to be sufficient to control the wrist joint with respect to the work plane posture. Forearm posture angle ranges were reduced when the prosthesis was operated companying environmental information in the user operation tests