Multi-Indenter Device for in Vivo Biomechanical Tissue Measurement

Abstract

Biomechanical tissue properties have been hypothesized to play a critical role in the quantification of prosthetic socket production for individuals with limb amputation. In this investigation, a novel indenter platform is presented and its performance evaluated for the purposes of residual-limb tissue characterization. The indenter comprised 14 position- and force-controllable actuators that circumferentially surround a biological residuum to form an actuator ring. Each indenter actuator was individually controllable in position ( [Formula: see text] accuracy) and force (330 mN accuracy) at a PC controller feedback rate of 500 Hz, allowing for a range of measurement across a residual stump. Data were collected from 162 sensors over an EtherCAT fieldbus to characterize the mechanical hyperviscoelastic tissue response of two transtibial residual-limbs from a study participant with bilateral amputations. At five distinct anatomical locations across the residual-limb, force versus deflection data-including hyperviscoelastic tissue properties-are presented, demonstrating the accuracy and versatility of the multi-indenter platform for residual-limb tissue characterization.

Sockets for Limb Prostheses: A Review of Existing Technologies and Open Challenges

“…However standard threshold values for the stress interface distribution within a socket are not available yet, also because they depend dramatically on the status of the patient residual tissues and on the prosthesis features. A step forward could be achieved through the use of multi-indenting devices, able to characterize the hyperviscoelastic properties of residual limb tissues and to investigate pain thresholds and tolerances for different anatomical areas [58].…”

3D Ultrasound Imaging of Residual Limbs With Camera-Based Motion Compensation

“…Ultrasound imaging techniques, like those described in this paper, can acquire detailed morphological information of the bone, soft tissue, and external shape of the limb. As such, our approach provides an innovative and costeffective means to collect useful data to create biomechanical models and perform FEA of residual limb soft tissue [5], [33], [34], [38].…”

Simultaneous Stiffness Measurement Device for a Human Forearm

“…To resolve these aforementioned issues, researchers have been studying prosthetic sockets from the viewpoint of residual limb stiffness around the prosthetic socket [11]- [14]. The proposed measurement device offers useful information in making the customized sockets for amputees.…”

“…Stiffness measurement devices for human limbs have gradually been an interesting topic regarding advanced prosthesis. In recent studies on such devices, Petron et al [11] developed a multi-indenter device that has a total of fourteen indenters surrounding the measurement site. Eleven of these indenters were used to anchor the measurement site and the remaining three indenters were used to measure the stiffness of the human limb.…”

“…The proposed device is used to estimate the actual indentation force by measuring the angle between the normal direction of the measurement skin site and the force direction of the indenter. The aforementioned existing indenters have only one DoF [8]- [11], [17], [18], but the developed indenter has two active DoFs and a passive joint that allows vertical indentation onto the skin. Additionally, the measurement system suggested in [11] was uncomfortable when measuring the stiffness because the subject would have to move their own limb whenever the measurement site changed.…”