Upper limb prosthesis

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prostheses (artifical devices use to support missing limb or body part)

Transcript of Upper limb prosthesis

  • 1. Rabia Mustafa shah KING EDWARD MEDICALUNIVERSITY

2. Prior to antiseptic surgery and antimicrobial drugs many amputations of the limb were caused by fractures . Although amputations of the upper limb may be presumed to have occurred from very early times the first record of an artificial device used for an upper limb amputation is thought to have come from the second Punic war 218- 201 BC 3. 6000 to 10,000 major amputations of upper limb occur every year in united states . Upper limb amputations with hand loss is extremely devastating , upper limb traumatic amputations occur twice as frequently as traumatic amputations of lower limb 4. 1- trauma Trauma is undoubtedly the largest producer of upper limb amputations and can include fractures , electrical , thermal burns , frostbite and machine injuries 2 - Tumor Significant improvements in cancer detection and treatment in recent decades are believe to have resulted in gradual decline in upper limb amputations 3- Disease Major limb amputations have been reported for vascular complications secondary to infections produced by drugs injected into back of hand or into wed spaces of digits. 5. Partial hand amputations may be considered to be any number of amputations involving any or all of digits or the radial or ulnar border of the hand. 6. The wrist disarticulation level amputation is usually performed when the partial hand residual limb is without thumb or fingers and when the motions afforded by the wrist and palm of the hands has virtually nothing to oppose it. 7. According to Taylor s a long trans radial amputation is defined as 8 to 10 inches from the centre of lateral Epicondyle to the end of the residual limb 8. . Amputation at the level of elbow disarticulation is performed for a variety of reasons. 9. The long or standard trans humeral amputation is defined as one of 50 to 90% of the length of a normal humeurs and is usually the level of choice for amputation above the elbow . 10. Shoulder disarticulation may be defined as any amputation of the arm from approximately 30% of the humeurs through the shoulder joint 11. Shoulder disarticulation is usually performed because of tumor . In the forequarter the clavicle and scapula are usually sacrificed as well as the entire length of the humeurs and the rest of the arm. 12. 1. Body powered prosthesis 2. Electrically powered prosthesis (Myoelectric prosthesis) 3. Hybrid prosthesis 4. Activity specific prosthesis 13. Body-powered prostheses represent a common type of prosthesis. These body-powered devices are durable , often weigh less than their electrical counterparts. Their mechanics depend on proprioceptive feedback through the harness system. Disadvantages of a body-powered prosthesis revolve around the restrictive nature of its design. The harness, which is required for functionality and suspension, limits the range of motion and functional envelope of the individual. 14. The functional envelope refers to the range of motion around a persons body in which he or she can operate the prosthesis without limiting or affecting the function of the contralateral limb. When a patient uses a prosthesis outside the functional envelope, it becomes difficult to operate a terminal device without having to use gross body motion. Long-term use of a body-powered prosthesis can accelerate shoulder issues and anterior muscle imbalances and lead to nerve entrapment within the contralateral axilla. 15. The electrically powered prosthesis provides more grip force and enhanced functional envelope, while reducing or eliminating the overall harnessing necessary with a body-powered prosthesis. 16. Many different designs are available. The term Myoelectric commonly is associated with electrical prostheses even though other electrical control modalities. These include Myoelectrodes, switches, slider-type input devices ( linear, transducers, or potentiometers) and force-sensing resistors (or touch pads). 17. Myoelectrodes collect and filter surface electromyogram signals generated through muscle contractions and convert those signals into a form that can influence electrical motors. Muscle sites are based primarily on the level of amputation and socket design. It typically include the anterior deltoid, biceps, wrist flexors, posterior deltoid, infraspinatus, teres major, triceps, and wrist extensors. 18. Any muscle that plays a reverse action or postural role should be evaluated carefully to avoid unwanted muscle contraction. A common example would be use of the trapezius for a Myoelectric control site. Another area of concern is using a muscle for Myoelectric control that is in close proximity to cardiac muscle. 19. A variety of motions are possible through different kinds of switching devices. Many switches are activated by pulling a cable or pressing a button. Switches are designed to perform multiple functions and come in many presentations. Harness-type switches rely on some type of pull to move the switch. 20. Depressing the switch with a chin, phocomelic finger, residual limb, or contralateral hand moves another type of switch, often referred to as a push switch. A push switch may be placed distal to the axilla on the inner side of the persons forearm on a transradial level amputee and activated by humeral abduction. More advanced switches are found in multiposition types of applications 21. Slider-type input devices convert distance, speed, or force into proportional movement of a prosthetic limb. As a result, feedback enhances proprioception. Slider-type input devices come in two varieties , the linear type of potentiometer is a input device that translates linear motion or into proportional function. Examples of this input device is the Linear Potentiometer. The second variety is the force-sensing type , such as Motion Control. 22. Some electrical prostheses employ a force- sensing Resistor . These types of input devices consist of a force-sensing resistor matrix. The amputee activates the force-sensing resistor by moving the shoulder complex, a phocomelic finger, residual humeral neck, or other residual anatomy. It reduces the incidence of phantom limb pain Special care is require in force-sensing resistors , Improper installation results in premature failure and greater expense and can produce uncomfortable perspiration, moisture, and uneven shear force. 23. The hybrid prosthesis combines the benefits of body-powered and electrical styles. This type of design allows simultaneous control of the elbow and terminal device and most commonly is simplified with the use of a body-powered elbow , electrical terminal device and wrist. In some cases, an amputee may choose a fully conventional system with an electronic wrist, but not usually as the first option. 24. The last prosthetic option is that of the activity- specific prosthesis. This type of prosthesis is designed for a specific activity where more typical prosthetic options are not sufficient. Patients use this custom device successfully for activities such as gardening, weightlifting, and skydiving. These special prostheses allow patients to resume meaningful activities and help life return to normal in a tangible way. These devices also physically show to the amputees family and friends that he or she is capable of doing many diverse activities 25. Current advances in upper limb technology can be divided into five categories, Treatment protocol Prosthetic interface Microprocessor technology Terminal devices 26. This process involves fitting the patient within 2 to 3 days, then following the patient consistently through occupational therapy This close interaction allows clinicians to evaluate better the interface, component choice , use and therapeutic issues. 27. A major determining factor of whether a patient will use a prosthesis comfortably is the design of prosthetic interface. One type of interface method is beginning to be used more frequently in upper limb prosthetics the roll-on suction suspension liner. This design helps provide a positive type of suspension, while eliminating suspension harnessing, which allows the incorporation of more functional control harnessing. Roll-on liners can be used with all type of prostheses, including Myoelectric prostheses 28. A suction-type design is used to stabilize the residual limb at the contours of Epicondyle. The transradial anatomic contoured socket contours the muscles of the residual limb and maintains a suspension that incorporates the benefits of the mediolateral and anterior-posterior contours of the residual limb. 29. Currently, microprocessor technology influences terminal device control wrist and elbow functions, and other options, such as shoulder joint locking and unlocking, remote on-and-off control, and sensory feedback. The microprocessor enhances input characteristics to produce the desired output optimizing prosthetic function and increasing overall ease of use. 30. Two breakthroughs in terminal device technology have had a significant impact on the future of electronic prostheses. The first is the introduction of water/dust resistant components. These new components function better in the real world and have fewer moisture-related problems. The second major development is that of speed.