A pressure and shear sensor system for stress measurement at lower limb residuum/socket interface

Abstract

A sensor system for measurement of pressure and shear at the lower limb residuum/socket interface is described. The system comprises of a flexible sensor unit and a data acquisition unit with wireless data transmission capability. Static and dynamic performance of the sensor system was characterised using a mechanical test machine. The static calibration results suggest that the developed sensor system presents high linearity (linearity error ≤3.8%) and resolution (0.9kpa for pressure and 0.2kpa for shear). Dynamic characterisation of the sensor system shows hysteresis error of approximately 15% for pressure and 8% for shear. Subsequently, a pilot amputee walking test was conducted. Three sensors were placed at the residuum/socket interface of a knee disarticulation amputee and simultaneous measurements were obtained during pilot amputee walking test. The pressure and shear peak values as well as their temporal profiles are presented and discussed. * Corresponding Author: Piotr Laszczak, Engineering Materials Research Group, Faculty of Engineering and the Environment, University of Southampton, SO17 1BJ, Southampton, UK; Email, P.Laszczak@soton.ac.uk; Phone, 07513362435 Preprint submitted to Medical Engineering and PhysicsMarch 1, 2016In particular, peak pressure and shear of approximately 58kPa and 27kPa, respectively, were recorded. Their temporal profiles also provide dynamic coupling information at this critical residuum/socket interface. These preliminary amputee test results suggest strong potential of the developed sensor system for exploitation as an assistive technology to facilitate socket design, socket fit and effective monitoring of lower limb residuum health.Abstract word count: 200

Implications of Multi-asperity Contact for Shear Stress Distribution in the Viable Epidermis – An Image-based Finite Element Study

“…bed-or wheel chair-ridden patients) as well as for prosthetics wearers where optimising comfort at the stump-prosthetic interface and preventing pressure ulcers is critical [17,48,49]. These experimental techniques and tools offer vast opportunities to be complemented by computational studies to gain a more mechanistic understanding of the interplay between the physical factors that contribute to primary skin injuries and that can ultimately evolve into more serious conditions such as chronic wounds [5,9,50].…”

Device-related pressure ulcers: SECURE prevention

“…98 In addition, technologies are available that sense interface pressure, shear, temperature and humidity. 161,162 Incorporating these technologies into medical devices will help avoid DRPU.…”

“…Sensor technologies and mechanisms that alert health professionals when excessive forces occur between skin and a device 161 or when tissues show an in ammatory response to the applied forces are another promising route for bioengineers to follow. An Future research and guidelines for product development example is pressure and shear sensing to measure stress at the limb residuum or socket interface for prosthetics.…”

“…An Future research and guidelines for product development example is pressure and shear sensing to measure stress at the limb residuum or socket interface for prosthetics. 161…”

“…Sensing and analysis technologies for pressure, shear stress and other biomechanical markers 93,94,161,162,166 and measures are already available or in development, as are biocapacitance examinations based on measurements of extravasated tissue uid (an early marker of in ammation). 134 Ultrasound can also be used to assess physiological changes in tissue.…”