scholarly journals Developing an Analogue Residual Limb for Comparative DVC Analysis of Transtibial Prosthetic Socket Designs

Materials ◽  
2020 ◽  
Vol 13 (18) ◽  
pp. 3955
Author(s):  
Kathryn Rankin ◽  
Joshua Steer ◽  
Joshua Paton ◽  
Mark Mavrogordato ◽  
Alexander Marter ◽  
...  
Keyword(s):  
Injury Risk ◽  
Load Transfer ◽  
Tissue Injury ◽  
Volumetric Strain ◽  
Image Correlation ◽  
Residual Limb ◽  
Prosthetic Socket ◽  
Strain Estimation ◽  
Design And Manufacture

Personalised prosthetic sockets are fabricated by expert clinicians in a skill- and experience-based process, with research providing tools to support evidence-based practice. We propose that digital volume correlation (DVC) may offer a deeper understanding of load transfer from prosthetic sockets into the residual limb, and tissue injury risk. This study’s aim was to develop a transtibial amputated limb analogue for volumetric strain estimation using DVC, evaluating its ability to distinguish between socket designs. A soft tissue analogue material was developed, comprising silicone elastomer and sand particles as fiducial markers for image correlation. The material was cast to form an analogue residual limb informed by an MRI scan of a person with transtibial amputation, for whom two polymer check sockets were produced by an expert prosthetist. The model was micro-CT scanned according to (i) an unloaded noise study protocol and (ii) a case study comparison between the two socket designs, loaded to represent two-legged stance. The scans were reconstructed to give 108 µm voxels. The DVC noise study indicated a 64 vx subvolume and 50% overlap, giving better than 0.32% strain sensitivity, and ~3.5 mm spatial resolution of strain. Strain fields induced by the loaded sockets indicated tensile, compressive and shear strain magnitudes in the order of 10%, with a high signal:noise ratio enabling distinction between the two socket designs. DVC may not be applicable for socket design in the clinical setting, but does offer critical 3D strain information from which existing in vitro and in silico tools can be compared and validated to support the design and manufacture of prosthetic sockets, and enhance the biomechanical understanding of the load transfer between the limb and the prosthesis.

scholarly journals Developing a control framework for self-adjusting prosthetic sockets incorporating tissue injury risk estimation and Generalized Predictive Control

2021 ◽  
Author(s):  
Florence M Mbithi ◽  
Joshua Steer ◽  
Andrew J Chipperfield ◽  
Alexander Dickinson
Keyword(s):  
Predictive Control ◽  
Lower Limb ◽  
Injury Risk ◽  
Tissue Injury ◽  
Risk Estimation ◽  
Soft Tissue Injury ◽  
Estimation Method ◽  
Generalized Predictive Control ◽  
Prosthetic Socket ◽  
Interfacial Pressure

Purpose: To perform activities of daily living (ADL), people with lower limb amputation depend on the prosthetic socket for stability and proprioceptive feedback. Poorly fitting sockets can cause discomfort, pain, limb tissue injuries, limited device usage, and potential rejection. Semi-passively controlled adjustable socket technologies exist, but these depend upon the user’s perception to determine safe interfacial pressure levels. This paper presents a framework for automatic control of an adjustable transtibial prosthetic socket that enables active adaptation of residuum-socket interfacial loading through localized actuators, based on soft tissue injury risk estimation. Method: Using finite element analysis, local interfacial pressure vs. compressive tissue strain relationships were estimated for three anatomical actuator locations, for tissue injury risk assessment within a control structure. Generalized Predictive Control of multiple actuators was implemented to maintain interfacial pressure within estimated safe and functional limits. Results: Controller simulation predicted satisfactory dynamic performance in several scenarios, based on previous related studies. Actuation rates of 0.06 – 1.51kPa/s with 0.67% maximum overshoot, and 0.75 – 1.58kPa/s were estimated for continuous walking, and for a demonstrative loading sequence of ADL, respectively. Conclusion: The developed platform could be useful for extending recent efforts in adjustable lower limb prosthetic socket design, particularly for individuals with residuum sensory impairment.

scholarly journals Predictive prosthetic socket design: part 2—generating person-specific candidate designs using multi-objective genetic algorithms

2019 ◽  
Vol 19 (4) ◽  
pp. 1347-1360 ◽  
Author(s):  
J. W. Steer ◽  
P. A. Grudniewski ◽  
M. Browne ◽  
P. R. Worsley ◽  
A. J. Sobey ◽  
...  
Keyword(s):  
Load Transfer ◽  
Expert Knowledge ◽  
Mechanical Design ◽  
Fine Tuning ◽  
Shape Optimisation ◽  
Residual Limb ◽  
Prosthetic Socket ◽  
Fibula Head ◽  
Optimisation Methods ◽  
Numerical Optimisation

AbstractIn post-amputation rehabilitation, a common goal is to return to ambulation using a prosthetic limb, suspended by a customised socket. Prosthetic socket design aims to optimise load transfer between the residual limb and mechanical limb, by customisation to the user. This is a time-consuming process, and with the increase in people requiring these prosthetics, it is vital that these personalised devices can be produced rapidly while maintaining excellent fit, to maximise function and comfort. Prosthetic sockets are designed by capturing the residual limb’s shape and applying a series of geometrical modifications, called rectifications. Expert knowledge is required to achieve a comfortable fit in this iterative process. A variety of rectifications can be made, grouped into established strategies [e.g. in transtibial sockets: patellar tendon bearing (PTB) and total surface bearing (TSB)], creating a complex design space. To date, adoption of advanced engineering solutions to support fitting has been limited. One method is numerical optimisation, which allows the designer a number of likely candidate solutions to start the design process. Numerical optimisation is commonly used in many industries but not prevalent in the design of prosthetic sockets. This paper therefore presents candidate shape optimisation methods which might benefit the prosthetist and the limb user, by blending the state of the art from prosthetic mechanical design, surrogate modelling and evolutionary computation. The result of the analysis is a series of prosthetic socket designs that preferentially load and unload the pressure tolerant and intolerant regions of the residual limb. This spectrum is bounded by the general forms of the PTB and TSB designs, with a series of variations in between that represent a compromise between these accepted approaches. This results in a difference in pressure of up to 31 kPa over the fibula head and 14 kPa over the residuum tip. The presented methods would allow a trained prosthetist to rapidly assess these likely candidates and then to make final detailed modifications and fine-tuning. Importantly, insights gained about the design should be seen as a compliment, not a replacement, for the prosthetist’s skill and experience. We propose instead that this method might reduce the time spent on the early stages of socket design and allow prosthetists to focus on the most skilled and creative tasks of fine-tuning the design, in face-to-face consultation with their client.

Anatomical and Surgical Risk Factors Affecting the Internal Mechanical Conditions in the Transtibial Residuum

2009 ◽  
Author(s):  
Sigal Portnoy ◽  
Ziva Yizhar ◽  
Noga Shabshin ◽  
Yaakov Itzchak ◽  
Anat Kristal ◽  
...  
Keyword(s):  
Risk Factors ◽  
Soft Tissues ◽  
Tissue Injury ◽  
Muscle Flap ◽  
Well Being ◽  
Internal Stresses ◽  
Residual Limb ◽  
Skin Damage ◽  
Prosthetic Socket ◽  
Superficial Skin

Transtibial amputation (TTA) patients face ongoing morphological changes in their residual limb. The residuum volume changes due to weight gain or loss, diurnal edema, and muscle atrophy. Consequently, the TTA prosthetic-user is fitted with a new prosthetic socket approximately every four years. Despite new innovations in socket and liner materials and design, contemporary prosthetics are not yet equipped to confront these changes. The TTA residual limb is therefore subjected to high superficial and internal stresses which may cause injury. Appending the hazardous condition of natural volume change of the residuum is the initial geometrical state of the truncated bones. The primary surgical considerations in TTA are the tibial length, the bevelment of the distal end of the tibia and the location of the surgical scar. These risk factors may significantly affect the well being of the TTA residuum. Previous studies assumed that the criteria for a well-fitted socket were low interface stresses. However, while interface stress measurements may help prevent superficial skin damage, knowledge of the internal stress distribution can prevent the formation of deep tissue injury (DTI) [1]. While superficial pressure ulcers are visually detected, DTI is concealed under the skin and spreads to its surroundings in the soft tissues of the residuum. If this latent wound is ignored, the skin will rupture to reveal a massive injury to skin, fat and muscle tissues, clinically termed as a type IV pressure ulcer. Our purpose was to evaluate the effect of the following risk factors on the internal mechanical condition of the TTA residuum: shorter tibial lengths (thicker muscle flap tissue), milder tibial end bevelments, different mechanical properties of the muscle flap (simulating both variance between patients or flaccid versus contracted muscle) and superficial scarring in inferior and anterior locations on the skin.

scholarly journals A framework for measuring the time-varying shape and full-field deformation of residual limbs using 3D digital image correlation

2019 ◽  
Author(s):  
Dana Solav ◽  
Kevin Mattheus Moerman ◽  
Aaron M. Jaeger ◽  
Hugh M. Herr
Keyword(s):  
High Resolution ◽  
Digital Image Correlation ◽  
Digital Image ◽  
Soft Tissues ◽  
Low Cost ◽  
Image Correlation ◽  
Time Varying ◽  
Residual Limb ◽  
Full Field ◽  
Prosthetic Socket

Effective prosthetic socket design following lower-limb amputation depends upon the accurate characterization of the shape of the residual limb as well as its volume and shape fluctuations. Objective: This study proposes a novel framework for the measurement and analysis of residual limb shape and deformation, using a high-resolution and low-cost system. Methods: A multi-camera system was designed to capture sets of simultaneous images of the entire residuum surface. The images were analyzed using a specially developed open-source three-dimensional digital image correlation (3D-DIC) toolbox, to obtain the accurate time-varying shapes as well as the full-field deformation and strain maps on the residuum skin surface. Measurements on a transtibial amputee residuum were obtained during knee flexions, muscle contractions, and swelling upon socket removal. Results: It was demonstrated that 3D-DIC can be employed to quantify with high resolution the time-varying residuum shapes, deformations, and strains. Additionally, the enclosed volumes and cross-sectional areas were computed and analyzed. Conclusion: This novel low-cost framework provides a promising solution for the in-vivo evaluation of residuum shapes and strains, as well as the potential for characterizing the mechanical properties of the underlying soft-tissues. Significance: These data may be used to inform data-driven computational algorithms for the design of prosthetic sockets, as well as of other wearable technologies mechanically interfacing with the skin.

Healing effects of curcumin nanoparticles in deep tissue injury mouse model.

2020 ◽  
Vol 18 ◽  
Author(s):  
Zirui Zhang ◽  
Shangcong Han ◽  
Panpan Liu ◽  
Xu Yang ◽  
Jing Han ◽  
...  
Keyword(s):  
Wound Healing ◽  
Mrna Expression ◽  
Tissue Injury ◽  
Inflammatory Cells ◽  
Pcr Analysis ◽  
Protective Effects ◽  
Deep Tissue ◽  
Deep Tissue Injury

Background: Chronic inflammation and lack of angiogenesis are the important pathological mechanisms in deep tissue injury (DTI). Curcumin is a well-known anti-inflammatory and antioxidant agent. However, curcumin is unstable under acidic and alkaline conditions, and can be rapidly metabolized and excreted in the bile, which shortens its bioactivity and efficacy. Objective: This study aimed to prepare curcumin-loaded poly (lactic-co-glycolic acid) nanoparticles (CPNPs) and to elucidate the protective effects and underlying mechanisms of wound healing in DTI models. Methods: CPNPs were evaluated for particle size, biocompatibility, in vitro drug release and their effect on in vivo wound healing. Results : The results of in vivo wound closure analysis revealed that CPNP treatments significantly improved wound contraction rates (p<0.01) at a faster rate than other three treatment groups. H&E staining revealed that CPNP treatments resulted in complete epithelialization and thick granulation tissue formation, whereas control groups resulted in a lack of compact epithelialization and persistence of inflammatory cells within the wound sites. Quantitative real-time PCR analysis showed that treatment with CPNPs suppressed IL-6 and TNF-α mRNA expression, and up-regulated TGF-β, VEGF-A and IL-10 mRNA expression. Western blot analysis showed up-regulated protein expression of TGF-β, VEGF-A and phosphorylatedSTAT3. Conclusion: Our results showed that CPNPs enhanced wound healing in DTI models, through modulation of the JAK2/STAT3 signalling pathway and subsequent upregulation of pro-healing factors.

scholarly journals Stamina-Enhancing Effects of Human Adipose-Derived Stem Cells

2021 ◽  
Vol 30 ◽  
pp. 096368972110354
Author(s):  
Eun-Jung Yoon ◽  
Hye Rim Seong ◽  
Jangbeen Kyung ◽  
Dajeong Kim ◽  
Sangryong Park ◽  
...  
Keyword(s):  
Physical Activity ◽  
Stem Cells ◽  
Locomotor Activity ◽  
Tissue Injury ◽  
Male Rats ◽  
Adipose Derived Stem Cells ◽  
Sprague Dawley ◽  
Serum Triglycerides

Stamina-enhancing effects of human adipose derived stem cells (hADSCs) were investigated in young Sprague-Dawley rats. Ten-day-old male rats were transplanted intravenously (IV) or intracerebroventricularly (ICV) with hADSCs (1 × 106 cells/rat), and physical activity was measured by locomotor activity and rota-rod performance at post-natal day (PND) 14, 20, 30, and 40, as well as a forced swimming test at PND 41. hADSCs injection increased the moving time in locomotor activity, the latency in rota-rod performance, and the maximum swimming time. For the improvement of physical activity, ICV transplantation was superior to IV injection. In biochemical analyses, ICV transplantation of hADSCs markedly reduced serum creatine phosphokinase, lactate dehydrogenase, alanine transaminase, and muscular lipid peroxidation, the markers for muscular and hepatic injuries, despite the reduction in muscular glycogen and serum triglycerides as energy sources. Notably, hADSCs secreted brain-derived neurotrophic factor (BDNF) and nerve growth factor in vitro, and increased the level of BDNF in the brain and muscles in vivo. The results indicate that hADSCs enhance physical activity including stamina not only by attenuating tissue injury, but also by strengthening the muscles via production of BDNF.

scholarly journals Tissue stress from laparoscopic grasper use and bowel injury in humans: establishing intraoperative force boundaries

2021 ◽  
Vol 3 (1) ◽  
pp. e000084
Author(s):  
Amanda Farah Khan ◽  
Matthew Kenneth MacDonald ◽  
Catherine Streutker ◽  
Corwyn Rowsell ◽  
James Drake ◽  
...  
Keyword(s):  
Small Bowel ◽  
Tissue Injury ◽  
Ex Vivo ◽  
Gastrointestinal Surgery ◽  
Convenience Sample ◽  
Thickness Change ◽  
Novel Device ◽  
Significant Difference ◽  
Laparoscopic Grasper

ObjectivesWe aim to determine what threshold of compressive stress small bowel and colon tissues display evidence of significant tissue trauma during laparoscopic surgery.DesignThis study included 10 small bowel and 10 colon samples from patients undergoing routine gastrointestinal surgery. Each sample was compressed with pressures ranging from 100 kPa to 600 kPa. Two pathologists who were blinded to all study conditions, performed a histological analysis of the tissues. Experimentation: November 2018–February 2019. Analysis: March 2019–May 2020.SettingAn inner-city trauma and ambulatory hospital with a 40-bed inpatient general surgery unit with a diverse patient population.ParticipantsPatients were eligible if their surgery procured healthy tissue margins for experimentation (a convenience sample). 26 patient samples were procured; 6 samples were unusable. 10 colon and 10 small bowel samples were tested for a total of 120 experimental cases. No patients withdrew their consent.InterventionsA novel device was created to induce compressive “grasps” to simulate those of a laparoscopic grasper. Experimentation was performed ex-vivo, in-vitro. Grasp conditions of 0–600 kPa for a duration of 10 s were used.ResultsSmall bowel (10), M:F was 7:3, average age was 54.3 years. Colon (10), M:F was 1:1, average age was 65.2 years. All 20 patients experienced a significant difference (p<0.05) in serosal thickness post-compression at both 500 and 600 kPa for both tissue types. A logistic regression analysis with a sensitivity of 100% and a specificity of 84.6% on a test set of data predicts a safety threshold of 329–330 kPa.ConclusionsA threshold was discovered that corresponded to both significant serosal thickness change and a positive histological trauma score rating. This “force limit” could be used in novel sensorized laparoscopic tools to avoid intraoperative tissue injury.

Mandibular Implant-Supported Overdenture: An In Vitro Comparison of Ball, Bar, and Magnetic Attachments

2013 ◽  
Vol 39 (3) ◽  
pp. 302-307 ◽  
Author(s):  
V. Manju ◽  
T. Sreelal
Keyword(s):  
Stress Distribution ◽  
Strain Gauge ◽  
Load Transfer ◽  
Implant Surface ◽  
Transfer Characteristics ◽  
Ball Bar ◽  
Different Types ◽  
Dial Gauge ◽  
In Vitro Comparison

In an implant-supported overdenture, the optimal stress distribution on the implants and least denture displacement is desirable. This study compares the load transfer characteristics to the implant and the movement of overdenture among 3 different types of attachments (ball-ring, bar-clip, and magnetic). Stress on the implant surface was measured using the strain-gauge technique and denture displacement by dial gauge. The ball/O-ring produces the optimal stress on the implant body and promotes denture stability.

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