Brief is based on interdisciplinary approach which is
Brief History/Reference core of the field
Prosthesis is an ancient Greek word which means attachment. It is an artificial replacement for the deprived part of the human body. Prosthetics fulfil the functionality of missing part of body as much as possible. This is the technology under healthcare and rehabilitation. It is based on interdisciplinary approach which is taken care by prosthetist and an interdisciplinary team of health care professionals including psychiatrists, surgeons, physical therapists, and occupational therapists. In the modern era Robotics has become the most important part of smart prosthetics. An artificial leg was made from iron and bronze. This discovery dates to 300 B.C. and was unearthed at Capua, Italy, in 1858.
Prosthetics has always been a part of human race since 424 B.C. From the ancient pyramids to world war I, prosthetic field has deformed in to an advanced example of human being’s vision to do better. The ambiguous road to the computerized leg began in about 1500 B.C. and has been evolving ever since. During the dark ages (476 to 1000) we got little improvements in prosthetics other than hand hook and peg leg by adding gyrating internal functions with springs and gears.
From the era of year 1400s to 1800s the new prospective of art, philosophy, science and medicine turned out to be the rebirth in the history of prosthetics. These were generally made of iron, steel, copper and wood.
From 1540’s to 1600, Amboise Pare, a French army barber introduced various new designs of prosthetics and outlined various amputation surgery methods., hence fourth he came to be known as father of modern amputation surgery. In between 17th and 19th centuries in 1696, diverse advancements were casted by people like Pieter Verduyn and James Potts. The first non-locking below-Knee Prosthesis was developed by Pieter Verduyn which afterwards became the blueprint of current joint and corset devices. The famous “Anglesey leg” was designed by James Potts from wooden shank and socket This era witnessed many improvements with ankle amputation which concealed tendons to simulate natural looking movement. This did not involve of amputating at the thigh or adding interior spring but still gave a smooth appearance. Douglas Bly invented and patented the Doctor Bly’s anatomical leg which in 1858 was considered “the most complete and successful invention in artificial limbs over that particular period. In 1863 first aluminium prosthesis was introduced.
Hanger, Selpho, Palmer and A.A. Marks transformed prosthetics field with continuous refinements in mechanisms and materials of the devices of the time. During world war 1 there was not much improvisation going on in this technology but the surgeon General of the army at that time realized the importance of this technology and he led to the formation of American orthotic &Prosthetic Association (AOPA). Use of lighter material, Patient-moulded devices, use of microprocessors, computer chips, and robotics all these valuable additions over a period made prosthetic technology more realistic with more functionality to match up with the natural behaviour of human limbs rather than just mechanical hardware.
Prosthetics technology is playing very important role in the healthcare sector for centuries but where can we take it in the future that’s the real question. Prosthetics are mostly responsible to provide basic mobility, improved functionality or social acceptance which can be in multiple forms E.G. peg legs, glasses and contact, fake arms, glass eyes etc. in terms of human body prosthetics technology can be divided into three sectors such as visual, arms, leg. Although there is no functionality replacement for human eye. When it comes to glass eyes it serves no function and glasses/contacts only serve to improve existing usually impaired eyesight. Prosthetics technology in arms has been improved dramatically. Artificial Legs are very common but there are many issues the comfort and effectiveness of a prosthesis are largely governed by how well it fits onto the remaining part of the patient’s own limb, which is called their residual limb. The connecting part of a prosthesis is called the socket and is carefully melded around a plaster cast taken from the residual limb. The fit of a socket must be precise otherwise it may generate discomfort for the residual limb, tissue damage and perhaps even making it impossible to wear by the patient. More precisely fitting sockets, called customised sockets, can now be made by 3D scanning a patient’s residual limb with lasers and cutting-edge techniques such as 3D printing are also now being used. In the case of the residual limb losing volume, the use of socks (liners) to compensate for the lack of contact or pressure on the prosthetic is normally adopted. Another issue that may happen is when patients have their first socket, they experience some swelling around their residual limb which will ultimately atrophy their remaining muscles causing them to shrink down the bones and creating discomfort inside their residual limb. Additionally, inadequate suction, causing the prosthesis to rotate or move up and down, is a common fitting problem due to limb shrinkage. Therefore, to be able to develop new prosthetic technology that will reduce internal discomfort an understanding and correlation of these areas of high pressure and volume changing must be evaluated and addressed. Analysis of pressure, friction, temperature, moisture (sudation problems) while using the prosthetics in day to day life is a challenging task. By gathering these real-time information, two main outcomes are key to the patient and the prosthetist: (1) the patient will know the state of their residual limb throughout the day and (2) prosthetist will know the exact cause of the patient’s discomfort pain during their day-to-day activities. This research work will focus on (1) designing a circuit and sensing system which can give the real-time analysis of conditions inside the socket and (2) integrating smart/soft robotics material within rigid prosthetic material to make a hybrid flexible auto-adjusted socket which will be adaptive in different working environments to give the full range of motions to patients.
S.C.O.T. implications theory suggest that dominant social events and figures will impact prosthetic technology in the next 20 years. This theory mainly responsible for funding given to researchers and experimentation, societal demand which involves war casualties and congenital disorders which could lead to medical advancements that physically restore body parts instead of humans fabricating them. Another important responsibility is contributing research advancements related to surgical advancements and engineering materials.
An ethical issue of prosthetics is based on important factor and that is affordability. Many of the people who wants prosthetics they can’t afford it because its cost more than 100,000 dollars for smart prosthetics. As prosthetics is not a onetime investment because we must replace it in 3-4 years. Also, we should replace the prosthetics limb more often. consistence use of prosthetics makes them worn out and dirty.so the people who make prosthetics could change this situation by using cheaper material but without compromising performance. In the health sector, the code of ethics represents the safety and rights of the people. Engineers must be very careful to meet the expectations of the most important aspects of ethics which are human rights. All the subjects in robotics engineering deals with the humans on some level. so, safety must be taken into consideration when we are dealing with artificial organs, prosthetics to improve the world in a safe, ethical, and honest way. In the field of prosthetics there are bio-medical engineer’s wo works on human body through different approaches. Interpreting the signals from the brain that receive input from nerves throughout the body, while others focus on the signals that the brain sends back to the body’s nerves and muscles to produce a reaction to the information received by the brain. Furthermore, other areas are responsible for the connection of the prosthetic limb to the human body and its nerves.
Electrical engineers and software engineers are responsible for developing and designing the electronics circuits and algorithms to process the signals and make the system autonomous with feedback control loop. It consists of converting received brain signals into computer-readable discrete signals to get the mechanical functionality. In this way the prosthetics gains the natural limb like functionality. The ideal prosthetic limb should follow these cognitive commands and respond without delay to get the natural feeling motion which s eventually the end goal of biomechanics specialists. It is extremely challenging to produce a natural, fluid movement out of a mechanical device because of material limitations as compare to natural human limb.
Finally, battery design is another most imp part of prosthetics because of power consumption of the artificial limb must be efficient otherwise the artificial limb usability will be very limited by time. Battery experts must make sure that the battery should be small enough to be perfectly fit the size of artificial limb and should not occupy extra space otherwise limb will get bigger in size. The charging intervals of battery while using should be comfortable so that at least with one charge a patient can use it to his single day. Sensors play utmost important role when it comes to response time from feedback control loop which eventually leads to better functionality of artificial limb. Humans feel different sensations through different ways in order to make any particular function possible. These sensations can be touch, temperature, pressure, friction and the speed and direction of movement. The purpose of implementing sensors in to the limb is to get more human like working in day to day life. Formerly, by adding sensors and feedback control loop we can narrow down the gap between the human and use of artificial prosthetic limb.
The reason behind involving multidisciplinary approach for artificial prosthetic limb is to fill up the gap between human and technology while keeping safety at highest priority. The significant achievement of regular motion with the use of mechanical device connected to a person’s nervous system, mechanical prosthetics have proven advantageous which can go a long way for the health of the amputee robotic legs. The mechanical movements produced by the prosthetic are much closer to the natural movements experienced in walking, stepping up stairs and other day to day activities. This means that the movement looks fluent and easy and minimizes the stress of movements from non-robotic prosthetics on the joints. This can save joints from excess casualty over time, and can make a more intelligent amputee. Furthermore, with the robotic capabilities of these enhanced prosthetics patient can have more functionality while using it in day to day life. These advanced robotic prosthetics are removing the limitations of disabled people with spinal cord injuries due to their speed of performing the movements. We want prosthetics which can do all the things which natural human limbs can do.
Since, this technology is getting brand new developments but no matter how much close we get to make it perfect we have no clue if it is long lasting and durable. After many testes, the materials are losing their quality after the long use by patients. This is the biggest challenge to be overcome before making this product available for public. Batteries should also be tested to minimize the overheating issues so that patients should not get harmed because of raising temperatures in their limb.
Economic & Industrial impact
The product of this calibre makes it costly and that’s why it should be durable Because of cost customers will obviously expect that this should be the one-time investment without losing efficiency of functionality over a period of time. We also want to make these products available to more customers. The cost of each prosthetic limb is so great, that only a very wealthy individual could afford one. Those wealthy individuals must also be amputees, and so this means there is only a small market for these products.
With all the benefits that come with an advanced robotic limb like the one we are creating, we want all amputees to be able to obtain our product in order to greatly improve the quality of their lives. Currently this is not an option. Amputees come in all shapes and sizes, with no two individuals having the same body measurements. This means that each product must be customized to fit the patient and individually connected to the central nervous system of that patient which is expensive and inefficient. Finally, another drawback that has been in discussion is if this product may give an unfair advantage to the patient. The materials our prosthetic is made from metals, unlike the natural human body. Could this possibly give someone an unfair advantage in using the prosthetic limb as opposed to using the natural body? Our overall goal in creating this product is to give normal, life-like function and sensation back to an amputee who has lost those aspects. However, we have not recreated a pain sensation, and this could possibly lead to the patient with the prosthetic being able to do more than could naturally be done with a natural limb. Combined with the materials that are stronger than skin and bones, having an artificial limb could potentially be better than keeping a natural appendage.
Leading research & Emerging technologies in this field
The Modular Prosthetic Limb (MPL), has taken the prosthetics technology to next level with its many advance capabilities which can support different uses as a prosthetics, human assistive device, or general robotic device. MPL promises to support patients with more enhanced, dexterous control of prosthetic arm and hand which includes the sense of touch. DARPA and APL are willing to work closely with prosthetic manufacturers and regulatory officials, exploring ways to transition this amazing technology to industry and make it less costly so that everyone can afford it. This tech is currently being in early clinical research phase and lost of testing is going on real patients. Technical advancements have been done in the following areas
(MPL – John Hopkins University Applied physics laboratory)
Previously any prosthetics limb is limited by flued motion because of lack of desired degrees of freedom but with this new update prosthetics has resulted in modular and stretchable limb with unprecedented degrees of freedom and controllable dexterity featuring.
§ Open system architecture bus structure
§ Open system principles for electronics and hardware components
§ Three-degrees-of-freedom shoulder
§ Integrated powerful elbow with active extension
§ Three-degrees-of-freedom wrist assembly
§ Articulated hand (10 actuated joints)
Fig 1.4 Fig 1.5 Fig 1.6
Fig 1.7 Fig 1.8
Ø Advanced actuation
§ Very-small-scale, powerful, and efficient integrated motors and transmissions
§ Microfluidics (full limb and dexterous hand applications for robotics)
§ Monopropellants, which are also applicable to robotics, particularly in extreme and austere environments (because of the unique catalytic system)
§ COBOT, a technology that has been demonstrated and can lead to many advanced applications (infinitely variable transmission with multiple independent outputs)
Image Credit: Johns Hopkins University Applied Physics Laboratory
Sensors are importantly responsible for collecting real time data collection, but size of sensors matters a lot in order to integrate them in to the limb while maintaining the compactness of prosthetics. So, there have been developments in the very small scale integrated sensors arena with potential applications to robotics.
Ø Socket technology
Prosthetics sockets have been always challenged with many different factors like sweating, air gaps, fitting issues and because of that soft tissues of the human limb got damaged because of consistent use of prosthetics and that’s leads to pain. Patients with amputee usually have complaints regarding their pain while using prosthetics even for 2 hours continuously so there are potential applications for technologies that improves suspension or secure attachments to the body, distribution of total weight, distribution of stabilization of dynamic forces, and heat dissipation for both military and civilian use.
Previously prosthetics have ben only made of metal or wood, but now soft smart materials have potential applications in contaminated environments.
Ø Virtual Integration Environment (VIE)
Prosthetics is fully functional when it consists of three main components hardware, sensors and communication. Communication interface between human body to send to mechanical movements of artificial limb is the most imp part of the artificial limb. Virtual Integration Environment is simplified, platform independent communication interface to the modular prosthetic limb. It completely changed the communicational approach with the integration of neuroscience and prosthetics research together. This change created common playing field that researchers and developers around the world can use to simulate and test new ideas. Visualizing and monitoring the performances of various designs approaches and pilot neural signal analysis algorithms is possible because of virtual integration environment. Simulating emerging mechatronics elements, train end- users to control real or virtual neuroprosthetic devices and configuring/customizing clinical/home devices are also important advantages with the use of VIE.
(John Hopkins VIE simulation- applied physics laboratory)
Ø Neural interface
Neural interface is responsible for eliminating the maximum gap between that robotic motion and fluid human like motion in prosthetic. Interfacing the human body’s nervous system for limb control and sensory feedback control made the system more precise. In electronics engineering there are different devices got explored and developed to acquire the electrical signals like EEG from many different locations from the human body specifically nerves and neuronal cells.
Photo courtesy of Blackrock Microsystems
Impact of prosthetics technology outside the field
Contributing research advancements for example, surgical advancements in both eye surgery and eye regeneration may eliminate the need for major operations like such as laser eye surgery and Lasik eye surgery. It may also happen that due to over-engineering of materials, glasses and contacts will become obsolete for eyes and likewise crutches for with the passage of years, this technology might be cheaply available to the society thereby providing many handicapped people the ability to perform all activities like education, leisure, play, social participation and sleep that required for daily living. This will not only reduce the dependency but will also enable them to work for their living. It will make large section of such people employed thereby eliminating disabilities by the end of the 21st century. The surgical and ethical issues in neuroprosthetics may get eliminated and as research advances, the sensory pathways may get restored in diseases like parkinson’s. this will again reduce the need of surgeries like neuroendoscopy, craniotomy and biopsy which include risks such as haemorrhage and infection.
Every year in the UK there are over 90,000 new cases of knee replacements and leg amputations happens. This is equivalent to approximately one every six minutes. Currently between 5-6000 major limb amputations are performed in the UK each year and 55% among them experience stress and pain. Artificial knee joints are most important when it comes to daily activities and if this technology is not efficient enough to give comfortable and adaptable behaviour to patients then there is a soft tissue damage problem in prosthetics socket and patients won’t be able to perform the daily activities comfortable and that will eventually hamper their lifestyle’s.