scholarly journals Accuracy Verification of Magnetic Resonance Imaging (MRI) Technology for Lower-Limb Prosthetic Research: Utilising Animal Soft Tissue Specimen and Common Socket Casting Materials

2012 ◽  
Vol 2012 ◽  
pp. 1-10 ◽  
Author(s):  
Mohammad Reza Safari ◽  
Philip Rowe ◽  
Arjan Buis
Keyword(s):  
Surface Area ◽  
Cross Sections ◽  
Lower Limb ◽  
Residual Limb ◽  
Cross Sectional ◽  
Prosthetic Socket ◽  
Semiautomatic Segmentation ◽  
Segmented Images ◽  
Cad Cam ◽  
Volume Measurements

Lower limb prosthetic socket shape and volume consistency can be quantified using MRI technology. Additionally, MRI images of the residual limb could be used as an input data for CAD-CAM technology and finite element studies. However, the accuracy of MRI when socket casting materials are used has to be defined. A number of six, 46 mm thick, cross-sections of an animal leg were used. Three specimens were wrapped with Plaster of Paris (POP) and the other three with commercially available silicone interface liner. Data was obtained by utilising MRI technology and then the segmented images compared to corresponding calliper measurement, photographic imaging, and water suspension techniques. The MRI measurement results were strongly correlated with actual diameter, surface area, and volume measurements. The results show that the selected scanning parameters and the semiautomatic segmentation method are adequate enough, considering the limit of clinical meaningful shape and volume fluctuation, for residual limb volume and the cross-sectional surface area measurements.

A New Proposed Method to Reverse Engineer a Residual Limb for Prosthetic Socket - Procedure, Advantages and Challenges

2016 ◽  
Vol 852 ◽  
pp. 558-563
Author(s):  
Divya Singh ◽  
Richa Pandey
Keyword(s):  
Lower Limb ◽  
Present Model ◽  
Body Part ◽  
Cad Model ◽  
Residual Limb ◽  
Reverse Engineer ◽  
Prosthetic Socket ◽  
Human Body Part ◽  
Cad Cam ◽  
Lower Limb Amputees

A prosthetic replaces any missing human body part visibly and also aims to resume the normal functionality of the part. Reverse engineering extracts information from a present model or available design and develops a new model using advanced CAD tools. Nowadays the reverse engineered part can be combined with rapid prototyping by various software and integration of CAD-CAM platforms. In this paper, a new method to reverse engineer the residual limb information for lower limb amputees, in order to use it for analyzing and developing a prosthetic socket by scanning and developing a CAD model is proposed. Along this are discussed, the advantages and challenges. This work falls in the emerging field of interdisciplinary engineering, combining medical and advanced mechanical engineering on a humanitarian platform

scholarly journals Three-dimensional Capsular Volume Measurements in Multidirectional Shoulder Instability

2018 ◽  
Vol 21 (3) ◽  
pp. 134-137
Author(s):  
Yong Cheol Jun ◽  
Young Lae Moon ◽  
Moustafa I Elsayed ◽  
Jae Hwan Lim ◽  
Dong Hyuk Cha
Keyword(s):  
Rotator Cuff ◽  
Surface Area ◽  
Three Dimensional ◽  
Volume Measurement ◽  
Control Group ◽  
Two Dimensional ◽  
Cross Sectional ◽  
Volume Measurements ◽  
Glenoid Surface ◽  
3D Software

BACKGROUND: In a previous study undertaken to quantify capsular volume in rotator cuff interval or axillary pouch, significant differences were found between controls and patients with instability. However, the results obtained were derived from two-dimensional cross sectional areas. In our study, we sought correlation between three-dimensional (3D) capsular volumes, as measured by magnetic resonance arthrography (MRA), and multidirectional instability (MDI) of the shoulder.METHODS: The MRAs of 21 patients with MDI of the shoulder and 16 control cases with no instability were retrospectively reviewed. Capsular areas determined by MRA were translated into 3D volumes using 3D software Mimics ver. 16 (Materilise, Leuven, Belgium), and glenoid surface area was measured in axial and coronal MRA views. Then, the ratio between capsular volume and glenoid surface area was calculated, and evaluated with control group.RESULTS: The ratio between 3D capsular volume and glenoid surface area was significantly increased in the MDI group (3.59 ± 0.83 cm³/cm²) compared to the control group (2.53 ± 0.62 cm³/cm²) (p < 0.01).CONCLUSIONS: From these results, we could support that capsular volume enlargement play an important role in MDI of the shoulder using volume measurement.

Subperiosteal expansion and cortical remodeling of the human femur and tibia with aging

Science ◽  
1982 ◽  
Vol 217 (4563) ◽  
pp. 945-948 ◽  
Author(s):  
CB Ruff ◽  
WC Hayes
Keyword(s):  
Cross Sections ◽  
Lower Limb ◽  
Torsional Rigidity ◽  
American Southwest ◽  
Cross Sectional ◽  
Human Femur ◽  
Second Moments

Increases with aging in subperiosteal dimensions and second moments of area (measures of bending and torsional rigidity) in femoral and tibial cross sections are documented in an archeological sample from the American Southwest. Significant differences between cross-sectional sites and between sexes in the pattern of cortical remodeling with age are also present. These differences appear to be related to variations in the stress or strain levels in different regions of the femur and tibia which result from in vivo mechanical loadings of the lower limb.

scholarly journals A Sensor Array for the Measurement of Relative Motion in Lower Limb Prosthetic Sockets

Sensors ◽  
2019 ◽  
Vol 19 (12) ◽  
pp. 2658
Author(s):  
Veronika Noll ◽  
Sigrid Whitmore ◽  
Philipp Beckerle ◽  
Stephan Rinderknecht
Keyword(s):  
Pilot Study ◽  
Relative Motion ◽  
Lower Limb ◽  
Sagittal Plane ◽  
Functional Model ◽  
Transverse Plane ◽  
Residual Limb ◽  
Test Rig ◽  
Prosthetic Socket ◽  
Dynamic Gait

The relative motion between residual limb and prosthetic socket could be a relevant factor in quantifying socket fit. The measurement of these movements, particularly in dynamic gait situations, poses a challenging task. This paper presents the realization of a measurement concept based on multiple optical 2D-motion sensors. The performance of the system was evaluated on a test rig considering accuracy and precision as well as accomplished measurement frequency and reliability of the system. Additionally, results of a pilot study measuring the relative motion between residual limb and prosthetic socket at seven specific locations of one individual with transtibial amputation during straight level walking are presented. The sensor functionality of the array was confirmed and the test rig experiments were comparable to the previously tested functional model ( e r r rel = 0.52 ± 1.87 %). With a sampling frequency of 1.3 kHz to be distributed among the number of sensor units, the developed system is suitable for investigating the relative movement between residual limb and prosthetic socket in dynamic gait situations. Results of the pilot study show the majority of relative motion occurring during the second half of the gait cycle. The measured relative motions show the residual limb sinking deeper into the socket, extending in the Sagittal plane and rotating internally in the Transverse plane during stance phase. Data captured during swing phase indicate a lower limb extension in the Sagittal plane as well as an external rotation in the Transverse plane.

scholarly journals Relationships between specific surface area and pore size in electrospun polymer fibre networks

2009 ◽  
Vol 7 (45) ◽  
pp. 641-649 ◽  
Author(s):  
S. J. Eichhorn ◽  
W. W. Sampson
Keyword(s):  
Cell Proliferation ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Cross Sections ◽  
Strong Influence ◽  
Polymer Networks ◽  
Polymer Scaffolds ◽  
Polymer Fibre ◽  
Cross Sectional

From consideration of the extent of contact between fibres in electrospun polymer networks, we provide theory relating the specific surface area of the network to the characteristic dimensions of interfibre voids. We show that these properties are strongly influenced by the cross-sectional morphologies of fibres. Whereas porosity has a strong influence on pore dimensions, in the range of porosities typically obtained in real networks, its influence on specific surface area is weak. By considering reference geometries of collapsed ribbons and fibres with circular cross sections, we demonstrate that at a given network porosity, fibre parameters that increase the specific surface area reduce the characteristic dimensions of voids. The implications of the theory, mainly in the context of cell proliferation on electrospun polymer scaffolds, are discussed; the theory has relevance also to future applications of these materials in composites.

scholarly journals Self-reported prosthetic sock use among persons with transtibial amputation

2013 ◽  
Vol 38 (4) ◽  
pp. 321-331 ◽  
Author(s):  
Krittika D’Silva ◽  
Brian J Hafner ◽  
Katheryn J Allyn ◽  
Joan E Sanders
Keyword(s):  
Management Strategies ◽  
Limb Loss ◽  
Self Report ◽  
Diurnal Changes ◽  
Residual Limb ◽  
Limb Volume ◽  
Cross Sectional Survey ◽  
Cross Sectional ◽  
Transtibial Amputation ◽  
Prosthetic Socket

Background: Daily changes in the shape and size of the residual limb affect prosthetic socket fit. Prosthetic socks are often added or removed to manage changes in limb volume. Little has been published about how persons with transtibial amputations use socks to manage diurnal changes in volume and comfort. Objectives: To investigate prosthetic sock use with a customized, self-report questionnaire. Study design: Cross-sectional survey. Methods: Persons with transtibial amputation reported number, thickness, and timing of socks used over a 14-day period. Results: Data from 23 subjects (16 males and 7 females) were included. On average, socks were changed less than once per day (0.6/day) and ply increased over the day (4.8–5.5 ply). Subjects wore prostheses significantly longer (15.0–14.1 h, p = 0.02) and changed socks significantly more often (0.6/day–0.4/day, p = 0.03) on weekdays compared to weekends. Participants were also divided into two subgroups: those who used socks to manage limb volume and those who used socks for socket comfort. Sock use did not differ (p > 0.05) between subgroups. Conclusions: Sock changes are infrequent among persons with lower limb loss. Initial, verbal reports of sock use were often inconsistent with data measured by logs. Tools (e.g. sock logs or objective instruments) to better understand sock-use habits among persons with limb loss are needed. Clinical relevance Knowledge of prosthetic patients’ sock use may help practitioners enhance volume management strategies or troubleshoot fitting issues. Results showed that subjects generally added socks to account for volume loss, and end-of-day sock thickness frequently exceeded 5 ply. Use of sock logs in clinical practice may facilitate improved residual limb health.

scholarly journals Characterising Residual Limb Morphology and Prosthetic Socket Design Based on Expert Clinician Practice

Prosthesis ◽  
2021 ◽  
Vol 3 (4) ◽  
pp. 280-299
Author(s):  
Alexander Dickinson ◽  
Laura Diment ◽  
Robin Morris ◽  
Emily Pearson ◽  
Dominic Hannett ◽  
...  
Keyword(s):  
Computer Aided Design ◽  
Principal Component ◽  
Population Based ◽  
Digital Design ◽  
Residual Limb ◽  
Design Features ◽  
Prosthetic Socket ◽  
Expert Clinician ◽  
Cad Cam ◽  
Successful Design

Functional, comfortable prosthetic limbs depend on personalised sockets, currently designed using an iterative, expert-led process, which can be expensive and inconvenient. Computer-aided design and manufacturing (CAD/CAM) offers enhanced repeatability, but far more use could be made from clinicians’ extensive digital design records. Knowledge-based socket design using smart templates could collate successful design features and tailor them to a new patient. Based on 67 residual limb scans and corresponding sockets, this paper develops a method of objectively analysing personalised design approaches by expert prosthetists, using machine learning: principal component analysis (PCA) to extract key categories in anatomic and surgical variation, and k-means clustering to identify local ‘rectification’ design features. Rectification patterns representing Total Surface Bearing and Patella Tendon Bearing design philosophies are identified automatically by PCA, which reveals trends in socket design choice for different limb shapes that match clinical guidelines. Expert design practice is quantified by measuring the size of local rectifications identified by k-means clustering. Implementing smart templates based on these trends requires clinical assessment by prosthetists and does not substitute training. This study provides methods for population-based socket design analysis, and example data, which will support developments in CAD/CAM clinical practice and accuracy of biomechanics research.

Balanced cross sections

1969 ◽  
Vol 6 (4) ◽  
pp. 743-757 ◽  
Author(s):  
C. D. A. Dahlstrom
Keyword(s):  
Surface Area ◽  
Cross Section ◽  
Cross Sections ◽  
Geological Environment ◽  
Simple Test ◽  
Cross Sectional ◽  
Mountain Belt ◽  
Sectional Plane ◽  
Bed Thickness ◽  
Better Than

Post-depositional concentric deformation produces no significant change in rock volume. Since bed thickness remains constant in concentric deformation, the surface area of a bed and its length in a cross-sectional plane must also remain constant. Under these conditions, a simple test of the geometric validity of a cross section is to measure bed lengths at several horizons between reference lines located on the axial planes of major synclines or other areas of no interbed slip. These bed lengths must be consistent unless a discontinuity, like a décollement, intervenes. Consistency of bed length also requires consistency of shortening, whether by folding and (or) faulting, within one cross section and between adjacent cross sections.The number of possible cross-sectional explanations of a set of data is reduced by the fact that, in a specific geological environment, there is only a limited suite of structures which can exist. This imposes a set of local "ground rules" on interpretation. When these local restrictions are coupled with the geometric restrictions which follow from the law of conservation of volume, it is often possible to produce structural cross sections that have a better-than-normal chance of being right.The concept of consistency of shortening can be extrapolated to a mountain belt as a whole, thereby indicating the necessity for some kind of transfer mechanism wherein waning faults or folds are compensated by waxing en echelon features. These concepts are illustrated diagrammatically and by examples from the Alberta Foothills.

scholarly journals Selecting Appropriate 3D Scanning Technologies for Prosthetic Socket Design and Transtibial Residual Limb Shape Characterisation

2020 ◽  
Author(s):  
Alexander Dickinson ◽  
Maggie Donovan-Hall ◽  
Sisary Kheng ◽  
Ky Bou ◽  
Auntouch Tech ◽  
...  
Keyword(s):  
Surface Area ◽  
Cross Sections ◽  
Best Practice ◽  
Design Method ◽  
Continuing Professional Development ◽  
3D Scanning ◽  
Average Deviation ◽  
Prosthetic Socket ◽  
Plaster Casting

Introduction: Plaster casting and manual rectification represent the benchmark prosthetic socket design method. 3D technologies have increasing potential for prosthetic limb design and fabrication, especially for enhancing access to these services in lower and middle income countries (LMICs). However, the community has a responsibility to verify the efficacy of these new digital technologies. This study’s objective was to assess the repeatability of plaster casting in vivo, specifically for clinically-relevant residuum shape and landmark capture, and to compare this with three clinically-used 3D scanners. Materials and Methods: A comparative reliability assessment of casting and 3D scanning was conducted in eleven participants with established transtibial amputation. For each participant, two positive moulds were cast by a prosthetist and digitised using a white light 3D surface scanner. Between casts, each participant’s residuum was scanned. The deviation between scan volumes, cross-sections and shapes was calculated.Results: 95% of the clinically-relevant socket shape surface area had a deviation between manual casts &lt;2.87mm (S.D. 0.44mm). The average deviation by surface area was 0.18mm (S.D. 1.72mm). The repeatability coefficient of casting was 46.1ml (3.47%) for volume, and 9.6mm (3.53%) for perimeters. For all clinically-meaningful measures, greater reliability was observed for the Omega scanner, and worse for the Sense and iSense scanners, although it was observed that the Sense scanner performance was comparable to casting (95th percentile shape consistency). Conclusions: This study provides a platform to appraise new clinical shape capture technologies in the context of best practice in manual plaster casting, and starts the conversation of which 3D scanning devices are most appropriate for different types of clinical use. The methods and benchmark results may support prosthetists in acquiring and applying their clinical experience, as part of their continuing professional development.

scholarly journals Characterising Residual Limb Morphology and Prosthetic Socket Design based on Expert Clinician Practice

2021 ◽  
Author(s):  
Alexander Dickinson ◽  
Laura Diment ◽  
Robin Morris ◽  
Emily Pearson ◽  
Dominic Hannett ◽  
...  
Keyword(s):  
Computer Aided Design ◽  
Principal Component ◽  
Population Based ◽  
Digital Design ◽  
Residual Limb ◽  
Design Features ◽  
Prosthetic Socket ◽  
Expert Clinician ◽  
Cad Cam ◽  
Successful Design

Functional, comfortable prosthetic limbs depend on personalised sockets, currently designed using an iterative, expert-led process, which can be expensive and inconvenient. Computer aided design and manufacturing (CAD/CAM) offers enhanced repeatability, but far more use could be made from clinicians’ extensive digital design records. Knowledge-based socket design using smart templates could collate successful design features and tailor them to a new patient. Based on 67 residual limb scans and corresponding sockets, this paper develops a method of objectively analysing personalised design approaches by expert prosthetists, using machine learning: principal component analysis (PCA) to extract key categories in anatomic and surgical variation, and K-Means Clustering to identify local ‘rectification’ design features. Rectification patterns representing Total Surface Bearing and Patella Tendon Bearing design philosophies are identified automatically by PCA, which reveals trends in socket design choice for different limb shapes that match clinical guidelines. Expert design practice is quantified by measuring the size of local rectifications identified by k-means clustering. Implementing smart templates based on these trends requires clinical assessment by prosthetists and does not substitute training. This study provides methods for population-based socket design analysis, and example data, which will support developments in CAD/CAM clinical practice and accuracy of biomechanics research.

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