Top PDF Pressure Distribution in Transtibial Prostheses Socket and the Stump Interface

Pressure Distribution in Transtibial Prostheses Socket and the Stump Interface

Pressure Distribution in Transtibial Prostheses Socket and the Stump Interface

The paper deals with the problem of a biomechanical solution for human locomotion after amputation of a lower limb. With an inappropriately designed transtibial prostheses socket, the interaction between the socket and the stump occurs, leading to increased friction and subsequent surface damage to the soft tissue. In individual types of transtibial prostheses, locations are defined which can be loaded and which cannot be loaded. On the basis of the study of the anterior side of the stump, three loadable and two non-loadable areas were monitored using the TACTILUS tactile pressure sensor (Sensor Products Inc., Madison, New Jersey, USA). Methods of measuring individual values were proposed for the purpose of sensing the pressure in the socket and the liner interface, the stump and the liner interface. Each method includes the methodological preparation of the patient, the preparation of the room, the preparation of the measuring system, and the subsequent method of data processing. In the submitted paper, 11 stumps were non-invasively monitored. The method of assessing the pressure exerted on the stumps was focused on the monitoring of the pressure distribution in the selected areas. The results obtained by the pressure measurements were statistically processed. In both cases of the pressure system placement, the p-value was higher than 0.05; therefore, we can state that the sets are equal.
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Interface pressure in transtibial socket during ascent and descent on stairs and its effect on patient satisfaction

Interface pressure in transtibial socket during ascent and descent on stairs and its effect on patient satisfaction

Four F-socket transducers 9811E (Tekscan, Inc., South Boston, USA) were attached to the posterior, anterior, lateral and medial compart- ments of the stump to obtain better insights on the pressure between the stump and socket. Medial, lateral and anterior sensors were at- tached at the mid patella level. The posterior sensor was positioned ap- proximately 1 cm above the posterior trim line of the socket. The residual limbs were covered with cellophane plastic wrap, and each transducer was attached to the cellophane plastic wrap with spray ad- hesive (Scotch Super Adhesive, 3M Corporate, St. Paul, USA) to ensure that the transducer was appropriately positioned on the stump. Each transducer was trimmed according to the contour of the stump. We enclosed 90% of the stump with these arrangements. Interface measure- ments were recorded using Tekscan software (version 6.51). Transduc- ers were positioned for equilibration and calibration inside a bladder and pressure of 100 kPa was applied according to the instructions of the manufacturer. We were aware of the limitations of the pressure measurement system employed, including hysteresis and drift. Inaccu- racies between individual cells have also been highlighted. However,
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A comparison between the dimensions of positive transtibial  residual limb molds prepared by air pressure casting and  weight-bearing casting methods

A comparison between the dimensions of positive transtibial residual limb molds prepared by air pressure casting and weight-bearing casting methods

Comparisons of comfort levels in both sockets showed a significant difference (p<0.05). The results showed that amputees were more satisfied with a tighter socket in the distal area and with more stump length in air pressure socket. These results are consistent with the results of Deutsch’s study (16). A probable reason of the ampu- tees’ higher satisfaction with air pressure casting can be attributed to uniform distri- bution of pressure on the residual limb, es- pecially in the circumferential areas and distal end of the residual limb. In a study by Tzeng et al (14), sensors were installed in a socket which was built through fluid pres- sure casting. It was concluded that pressure distribution in sockets cast through air pres- sure method is smoother than other casting methods. Other probable reasons that de- scribe why amputees find the sockets pre- pared by air pressure casting method more comfortable may include factors such as tight fitting of the sockets, no need to stockinet, less rotation movement of stump inside the socket, and no contact between the distal end of tibia and socket’s end as the socket cast is longer.
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Sensing and actuation technologies for smart socket prostheses.

Sensing and actuation technologies for smart socket prostheses.

As mentioned earlier, the stiffness of the matrix polymer influenced the performance of FBG sensors for stress measurements. Different matrix materials were investigated by Al-Fakih et al. [83] for attaining the most efficient and accurate stress measurements at the residual limb-prosthesis interface. The results revealed that harder and thicker matrix materials exhibit higher sensitivity and accuracy when used in the socket. In a sperate study conducted by the same group [84], FBG elements were embedded in a thin layer of epoxy-based sensing pad for in-socket stress measurements. The FBG-instrumented epoxy pad was embedded in a silicone polymer to form an in situ pressure sensor. The performance of the FBG-epoxy sensor was tested by inserting and inflating a heavy-duty balloon into the socket using compressed air to simulate the similar condition of a transtibial amputee’s patellar tendon bar. The sensors exhibited a sensitivity of 127 pm/N with full-scale output hysteresis of ~ 0.09. This study validated the reliability of FBG-based pressure sensors for in situ pressure measurement. However, like many piezoresistive pressure sensors, most FBG-based pressure sensors could only measure normal stresses. Zhang et al. [85] reported a soft polymer-based FBG (PFBG) for simultaneously measuring shear and normal stresses. The sensor was fabricated with one horizontal and another inclined PFBG embedded in a soft polydimethylsiloxanes (PDMS) matrix. The proposed sensor was tested by simultaneously applying normal and shear forces. The measured pressure sensitivity was found to be 0.8 pm/Pa within the range of 2.4 kPa, and its shear stress sensitivity was reported to be 1.3 pm/Pa for a full range of 0.6 kPa.
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Systematic review of effects of current transtibial prosthetic socket designs—Part 2: Quantitative outcomes

Systematic review of effects of current transtibial prosthetic socket designs—Part 2: Quantitative outcomes

The current review also revealed that variability exists in interface pressure measurements between vari- ous studies, perhaps because of differences in prosthetic componentry, prosthetic alignment, pressure measure- ment equipment, and position of sensors [33]. Neverthe- less, trends indicate that TSB sockets result in fewer pressure problems than PTB sockets [17]. In a PTB socket, the popliteal area experiences the highest pres- sure, followed by the patellar tendon and the anterior dis- tal tibia region. In a TSB socket, however, the pressure distribution depends on the liner used: pin lock liners show a so-called “milking effect” with high positive pressures occurring at the proximal region of the residual limb and negative pressure occurring at the distal area of the residual limb. This possibly causes the fluids to draw into the limb with each step taken [27,30,41]. The high pressure area for Seal-In liners seems to be typically over the middle part of the residual limb due to the five seals around the outer surface of the liner [30]. The thickness of the liner could be effective in reducing interface pres- sure over bony prominences, as shown by Boutwell et al. [33]. Apart from accuracy and repeatability of the pres- sure measurement tools and related procedures, the main challenge with the studies on interface pressure measure- ment is the lack of knowledge about the pressure levels for an ideal socket fit. Although studies have been con- ducted to measure residual limb load tolerance thresholds on limited regions of the residual limb, more research is required in this area [54–55]. For example, exploring
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Clinical implication of interface pressure for a new prosthetic suspension system

Clinical implication of interface pressure for a new prosthetic suspension system

Prosthesis is suspended through application of pressure at various sites of stump. This can considerably affect the comfort during ambulation. The pin/lock users experi- ence traction at the distal stump during the swing phase [11]. Simultaneously, proximal tissues bear high compression that may interrupt the fluid stream. This phenomenon may cause vein problems and edema. It can also result in the color change and skin thickening, especially at the distal area of the residual limb [11]. This study conjectured that increased contact area with the HOLO system may decrease the stretch. Signifi- cant differences were observed at different stump surfaces (Table 2). Less peak pres- sures were seen at the proximal and distal residual limb on all surfaces with the HOLO system during the swing phase of gait. This was compatible with the results of Beil and Street [11] Beil and Street [11] reported more uniform interface pressure with a suction system [11]. The current research is in line with their findings as the distribution of pressure with the pin/lock was less uniform in comparison to the HOLO system; yet HOLO is not a suction system. Similar to the suction system, the residual limb had higher contact with the socket in the new system compared with the pin/lock suspen- sion. High contact between the socket and stump could produce more uniform pres- sure. In HOLO, the pressure was mostly concentrated at the middle of the residual limb; similar to the Seal-In liner [27]. This might be due to the location of the Velcro in the new system compared with the seal area in the Seal-In system. This was compat- ible with the findings of Ali et al. [27].
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Interface pressure in transtibial socket during ascent and descent on stairs and its effect on patient satisfaction

Interface pressure in transtibial socket during ascent and descent on stairs and its effect on patient satisfaction

(Scotch Super Adhesive, 3M Corporate, St. Paul, USA) to ensure that the transducer was appropriately positioned on the stump. Each transducer was trimmed according to the contour of the stump. We enclosed 90% of the stumpwith these arrangements. Interface measurements were recorded using Tekscan software (version 6.51). Transducers were positioned for equilibration and calibration inside a bladder and pressure of 100 kPa was applied according to the instructions of the manufacturer. We were aware of the limitations of the pressure measurement system employed, including hysteresis and drift. Inaccuracies
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Interface pressure between socket and residual limb in prosthesis with seal-in X5 and dermo liner during level ground, stairs, and ramp walking /Sadeeq Ali

Interface pressure between socket and residual limb in prosthesis with seal-in X5 and dermo liner during level ground, stairs, and ramp walking /Sadeeq Ali

To determine the quality of transtibial prosthesis, prosthetic training is given to the patient by a therapist (Fig. 2.36).The significance of good gait training cannot be overstated. Several new amputees think that learning to walk with their prosthesis will be simple, and that seeing a physical therapist for strengthening and gait training is not necessary. These new amputees should understand that walking with prosthesis may not be as simple as they believe. In reality, most new amputees require months of practice with their prostheses. Most of the time, repetitive gait training and specific alterations are necessary before a person’s gait becomes even, steady, and, most importantly, secure. In addition, a patient normally takes three months to nine months to regain the power and flexibility in their leg. Amputees, therapists, and prosthetists will work as a team to ensure that the rehabilitation is as quick and successful as possible. Gait analysis, a helpful analytical tool, is the systematic study of amputee locomotion, more specifically as a study of human motion, which uses the eye and the brain of observers, augmented by instrumentation for measuring body movements, body mechanics, and muscular activity. Gait analysis is used to assess, plan, and treat individuals with conditions affecting their ability to walk (Whittle, 2003).
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Assessment of a pressure-cast socket for transtibial prostheses in under-resourced environments

Assessment of a pressure-cast socket for transtibial prostheses in under-resourced environments

In the current study, the majority of the high pressures were seen at locations in the proximities of the bony prominences of the tibial crest and fibular head, which are more likely to experience skin breakdown [17]. Previous studies have quantified the regional load-bearing ability of the residual limb., Zhang and Lee applied gradually increasing forces using a 12 mm diameter indenter to different regions of the residual limb surface of eight people with unilateral transtibial amputation [187]. Tolerable pressures at the distal tibia and fibular head were quantified as 600 ± 150 kPa and 820 ± 240 kPa respectively [187]; values much greater than any seen in the current study. Zhang and Lee recorded the subjective pain thresholds of the participants, which does not equate to the physiological tolerance of the different sites to pressure. Further, the loads were not applied in a cyclic manner as in gait. There is a wealth of literature exploring the relationships between applied pressure and tissue breakdown, however these generally concern the development of pressure sores among populations who are immobilised or neurologically impaired [17, 184-186]. Such relationships are likely not directly transferable to prosthetic users due to the different anatomical locations, loading durations and loading frequencies studied. Although there is insufficient data in the literature to evaluate the likelihood of tissue breakdown for the values herein, significant differences and medium to very large effects in loading duration were seen between the HighSCS and LowSCS participants for both the region and the MPL data. Such results indicate that loading durations may be important in understanding wearer comfort, and potentially skin at risk of breakdown, and should be included in further studies of socket interface pressures.
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Clinical investigation of the interface pressure in the trans tibial socket with Dermo and Seal In X5 liner during walking and their effect on patient satisfaction

Clinical investigation of the interface pressure in the trans tibial socket with Dermo and Seal In X5 liner during walking and their effect on patient satisfaction

Two transtibial prostheses were made for each subject, one with the Dermo liner with shuttle lock (Icelock-200 series) and another with the Seal-In X5 linerwith valve (Icelock Expulsion, Valve 551). All the prostheses were fabricated with Flex-Foot Talux (Ossur, Reykjavik, Iceland). One registered prosthetist fabricated all the prostheses to avoid alterations due to manufacturing, alignment and fitting. A total surface bearing (TSB) socket was fabricated for all the subjects (Staats and Lundt, 1987). In order to become familiar with their new prosthetic devices, the subjects practiced walking in the motion analysis laboratory (Biomedical
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An experimental animal model of aseptic loosening of hip prostheses in sheep to study early biochemical changes at the interface membrane

An experimental animal model of aseptic loosening of hip prostheses in sheep to study early biochemical changes at the interface membrane

The femora and the joint capsule of each operated limb were collected immediately after sacrifice of the animals. The bones were put on ice until further processing. Trans- verse bone sections were made of the femur with a special bone saw (Exakt System, Norderstedt, Germany). In order to get a good distribution and random selection of tissue samples throughout the femoral shaft, the sections were made according to five different regions. These regions were delineated with the aid of the same radiographic template used to determine the femoral implant size (R1 to R5) as described before (Fig 1). To facilitate sectioning of the bone slices, the femoral metal component within the cement mantle was carefully removed in a retrograde fashion. The first cut in the femur was placed immediately below the distal tip of the implant as measured by the template (Region 1-R1). Then, the femoral metal compo- nent was mobilized by placing an intramedullary Stein- mann pin on the distal aspect of the stem while cautiously tapping with a hammer on the tip of the pin until the implant was freed from the cement mantle without break- ing or loosening the bone cement itself. From each bone region, another bone slice was cut and split in half longi- tudinally such that the bone cement could be carefully removed and the interface membrane between the bone and the cement was exposed.
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Roll pressure distribution in strip rolling

Roll pressure distribution in strip rolling

A technique has been developed in which the pressure distribution and roll separating load are determined from consideration of the elastic deformation of the rolls during operation. By interrupting a rolling pass before completion, the shapes of the deformed rolls are imparted to the workpiece surface. Accurate measurement of the imparted profiles at several sections across the width of the workpiece allows the extent of the elastic deformation of the roll to be determined. An analytical solution based on solid body contact theory was used to determine the pressure distribution responsible for the elastic deformation along each section. The solution incorporates experimentally determined parameters and functions relating to specific mill-stands and schedules.
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Review Socket Programming

Review Socket Programming

Sockets are interfaces that can "plug into" each other over a network. Once so "plugged in", the programs so connected communicate. This article discusses only simple aspects of stream inet sockets (don't worry about exactly what that is right now). For the purposes of this article, a "server" program is exposed via a socket connected to a certain /etc/services port number. A "client" program can then connect its own socket to the server's socket, at which time the client program's writes to the socket are read as stdin to the server program, and stdout from the server program are read from the client's socket reads. This is one subset of socket programming, but it's perhaps the easiest to master, so this is where you should start.
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Design Of A Mechanism For A Robotic Transtibial Prosthesis

Design Of A Mechanism For A Robotic Transtibial Prosthesis

As showed in Fig. 1, the mechanical design was modeled using Autodesk Inventor Professional which is an extensively complete CAD software. The foot design is similar to the one developed by Dobson, Wei, and Ren and it consists of: An ABS plastic sole (that can be manufactured with 3D printers) with cavities for pressure sensors which measure the weight of the amputee and serve to detect the current subphase of the stance phase in which the user is. A designed universal joint (DUJ) which is divided in an upper and a lower part, containing 2 crossed stainless steel shafts for IE and DP turns, and some pieces of rubber to counteract the impacts and limit the movements. An ABS plastic plate (that can be 3D printed) which is assembled to the sole and the DUJ. The DUJ is connected to the lower support of the serial elastic actuators (SEAs). Each SEA consists of: Two springs (one for dorsiflexion and one for plantarflexion). An inner stainless steel bar which guides both springs. A stainless steel tube which encapsulates the springs and the guide above mentioned. Two commercial MiSUMi UNCA14 universal jointsset pin (CUJ) with 26000 N of static tensile failure load. A block of linear movement which connects the upper CUJ and the nut. An SKF SH 12,7x12,7 R precision rolled ball screw. Two ball bearings which hold the ball screw. A Maxon motor DCX35L GB KL 12V of 77.7 mNm nominal torque and 6A nominal current. A Maxon gearhead GPX37 LN of reduction 3.9:1 and maximum intermittent torque of 2.3 Nm. A rigid coupling between the ball screw and the motor. The structure
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Stereotactic body radiation therapy for patients with recurrent pancreatic adenocarcinoma at the abdominal lymph nodes or postoperative stump including pancreatic stump and other stump

Stereotactic body radiation therapy for patients with recurrent pancreatic adenocarcinoma at the abdominal lymph nodes or postoperative stump including pancreatic stump and other stump

Notes: each patient had sBrT beam angle, cross-sectional, sagittal, and coronal images taken, and red and purple lines indicate gTV and PTV, respectively. (A) a 64-year-old female treated for a solitary recurrent pancreatic adenocarcinoma at the stump. sBrT was performed using six fractions of 42 gy prescribed to the 72% isodose line. (B) A 55-year-old male treated for a solitary recurrent pancreatic adenocarcinoma at the abdominal lymph node. SBRT was performed using five fractions of 45 Gy to the 75% isodose line.

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Quantification of Transhumeral Prosthetic Socket Residual Limb Interface Movement Using Motion Capture and a Slip Detection Sensor

Quantification of Transhumeral Prosthetic Socket Residual Limb Interface Movement Using Motion Capture and a Slip Detection Sensor

Current literature focusing on the prosthetic socket is limited by measurement techniques and modeling assumptions, leading to a limited understanding of the forces and motions occurring between the residual limb and prosthesis and how they can be used to influence socket design and fitting. Prosthetic socket fitting and prescription would benefit from an elegant method for comparing socket designs. This dissertation focuses on the development and implementation of a 3D motion capture model and a Slip Detection Sensor to quantify rotations and translations at the prosthetic socket-residual limb interface. The 3D motion capture model defines the residual limb bone position inside the prosthetic socket which allows for measurement of the movement occurring at the prosthetic socket interface. The Slip Detection Sensor is an optoelectronic sensor embedded into the prosthetic socket wall to measure the amount of socket slip occurring between the socket wall and the residual limb skin surface. The motion capture model and Slip Detection Sensor were used to measure motion at the socket interface of transhumeral amputees during activities of daily living. Data were collected on six transhumeral amputees in the University of South Florida’s (USF) motion analysis laboratory. One of the participants completed the collection procedures twice using two different suspension systems (pin locking versus no pin locking) within the same socket.
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Breast Prostheses

Breast Prostheses

Whatever type of surgery you have had, you will not be able to wear anything that puts pressure on your scar and the surrounding area for 6 to 8 weeks. When your scar has fully healed you might need to have further treatment such as radiotherapy, which can make your skin tender and sensitive for a while. You may find it more comfortable to wear your temporary prosthesis until this sensitivity has gone completely. You might decide to carry on using your temporary prothesis for leisurewear or at night.

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Socket Programming

Socket Programming

2. N ETWORK PROGRAMMING WITH SOCKETS : The Internet has been very popular in the past few years. With its popularity still growing, increased demand for Internet network software has grown as well. One of the greatest advantages to developing Internet software with Java is in its robust networking support built into the core language. The java.net package provides us with classes representing URLs, URL connections and sockets. Combined with the java.io package, we can quite easily write sophisticated platform-independent networking (Internet) applications. Network programming makes use of socket for Interprocess Communication. Due to which Network programming is also termed as socket programming. In Socket programming using Java, BSD style Socket to Interface with TCP/IP services is used. BSD Socket Interface provides facilities for Interprocess Communication. BSD Socket Interface supports different domain, the UNIX Domain, the Internet Domain and the NS Domain. Java Basically supports the Internet Domain to maintain cross platform. In Internet Domain, the BSD Socket Interface is built on the top of either TCP/IP or UDP/IP or the raw Socket. Socket Programming is important to understand how internet based interprocess communication work but not at the level program developed but at a higher level that is compiled to set of Socket Programs. Here sockets can also be termed as network socket or Internet socket since communication between computers is based on Internet protocol.
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Wear of knee prostheses

Wear of knee prostheses

of the tribology and wear of polyethylene in knee joint replacements and is based on research carried out over the last decade. In particular, it describes new scientific findings and knowledge about the different variables that control degradation and wear of polyethylene in the knee and that contribute to failure of knee prostheses. It focuses on the needs of high-demand patients with long life expectancies, such as active patients in their early 50s, who walk or run up to two million steps every year, 3

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Review Article Simple ligation versus stump invagination for the appendix stump: a systematic review and meta-analysis

Review Article Simple ligation versus stump invagination for the appendix stump: a systematic review and meta-analysis

Abstract: Aim: To evaluate the clinical efficacy and safety of simple ligation (SL) and stump invagination (SI) to treat the appendix stump. Methods: The Cochrane Library, Embase, Pubmed, Web of science, VIP, and Wanfang data- bases were searched systematically to identify relevant randomized controlled trials (RCTs) and quasi-RCTs. The study quality was assessed and the relevant data was extracted. Inter-study heterogeneity was assessed using the Cochran Q test, the I 2 test, and the Galbraith figure. The source of heterogeneity was determined using subgroup and

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