Bionic Arms

IntroductionThe Manufacture of BionicArmsThe Drawbacks of BionicArmsFuture Outlook

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IntroductionWhy do you need a bionic arm? Some people are born with limbloss (congenital limbdeficiency), while others maylose limbs due to infections,trauma, cancer, or complicationsthat arise in blood vessels. Thenonprofit Amputee Coalitionestimates about 2 millionamputees in the U.S., and thatnumber is expected to nearlydouble to 3.6 million by 2050. Vascular disease, includingdiabetes and peripheral arterydisease, accounts for 54% of allamputations in the U.S. Othermajor causes are trauma (45%) andcancer (less than 2%). Amputation presents bothphysical and emotionalchallenges. The

Basic artificial limbs havebeen used since 600 B.C. Theyprovide very little or nofunctionality and are simplyworn to give a naturalappearance of a limb.Traditional upper-limbprostheses use cables and

loss of a leg or arm can impacta person’s ability to walk orbalance correctly. Even thesimplest daily tasks can turninto a challenge for them. Anamputation is a traumaticexperience, causing the victimto relive the memories thatcaused the accident. Around 30%of people with limb lossexperience depression and/oranxiety. Many individuals alsosuffer from issues regardingbody image and how othersperceive them.

Implanting an artificial limbthat replaces a missing bodypart can be an optimal choicefor amputees. Its goal is toreplace as much function of theoriginal limb as possible. Atthe very least, a prostheticshould help an amputee takecare of necessary dailyactivities such as eating,walking, and getting dressed ontheir own.

What is the function of bionicarms?

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as living organisms or parts ofliving organisms. A bionic limbgives the user much morecontrol and movement throughthe use of sensors andcomputers that respond to boththoughts and muscle movement.This functionality takes muchof the workload off of theuser’s body and acts moresimilar to a real limb.Ultimately, bionic limbsprovide much more ease andfunctionality when compared totraditional prosthetic limbsand require less effort fromthe user.

AI technologies applied tobionic armsArtificial intelligence (AI) isevolving rapidly in healthcare.

harnesses attached to theindividual and rely on bodymovements to manipulate cablesthat control the prosthetic limb.This can be physically tiring,cumbersome, and unnatural.Functional prosthetics aretypically available in both body-powered and electrically poweredforms, with the electricallypowered option relying onbatteries and motors to powermovements. This type ofprosthetic will react based ondetected muscle movements in theresidual limb or upper body.

The term ‘bionics’ was first usedin the 1960s. It combines theprefix ‘bio’—meaning life—withthe ‘nics’ of electronics.Bionics is the study ofmechanical systems that function

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Boosting clinicaleffectiveness byimproving quality,safety, and efficiencyExtending access andexpanding service Supporting patientengagementProviding affordablecare through optimizingworkflows

Digital HealthInformation: Machine learning/deep

learningNatural languageprocessingAI assistance and voicetechnologyMedical robots

Powered Automation:

Human-machine Partnership in Healthcare

Source: Artificial intelligence in healthcare: An essential guide for health leaders

the ultimate goal is toproduce a refined prostheticthat amputees can wear intheir daily lives.

The Manufacture ofBionic ArmsA number of bionic arms arenow available which arebeginning to mimic some of thefunctionality of theoriginally lost limbs. Othersare still at the research anddevelopment stage but areshowing great promise. Thefollowing is a briefintroduction and manufacturingprocess for several differenttypes of prosthetic arms.

External Prosthetic LimbsMyoelectric limbs use abattery and electronic systemto control movements. Eachprosthesis is custom made,attaching to the residual limbusing suction technology. Oncethe device has been securelyattached, it uses electronicsensors to detect even thesmallest traces of muscle,nerve, and electrical activityin the remaining limb. Thismuscle activity is transmittedto the surface of the skinwhere it is amplified and sent

The AI technologies can be usedas powerful tools and partners toenhance, extend, and expand humancapabilities, delivering thetypes of care patients need, atthe time and place they needthem. Humans and AI can form apartnership to improve clinicaleffectiveness (ie, quality,safety, and efficiency), access,and affordability of care.Medical robots equipped with AItechnology can help with surgicaloperations, rehabilitation,social interaction, assistedliving, and more.

Fast-moving research on improvingbionic limbs is being conductedto improve people’s lives byrestoring both movement andfeeling. In 2020, thanks to a newimplant system, patients withmind-controlled arm prostheseswere able to experience asensation of touch. This news wasencouraging, but we still have alimited understanding of how ourbrain manages to do movementsexactly. Processing the amount ofdata running between our brainand limbs will require moreadvanced algorithms as technologyadvances. To fill this gap,attempts are being made toincorporate AI technology intobionic arms. For now, the AI-enabled artificial limb remainsin the testing stage, but the

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to microprocessors, which usethe information to control themovements of the artificiallimb. Based on the mental andphysical stimulus provided bythe user, the limb moves andacts as a natural appendage.By varying the intensity ofthe movement of their existingfunctional muscles the usercan control aspects such asstrength, speed, and grip inthe bionic limb. If musclesignals cannot be used tocontrol the prosthesis,switches with a rocker, pull-push, or touchpad can be used.Improved dexterity is achievedvia the addition of sensorsand motorized controls, thusenabling users to performtasks such as using a key toopen a door or getting cardsout of a wallet. An addedbonus of the myoelectric limbis that, same as traditionalbody-powered devices, it canbe made to replicate theappearance of a natural limb.

OsseointegrationOsseointegration (OI) is aprocess creating directcontact between living boneand the surface of a synthetic—often titanium‐based—implant.The procedure uses askeletally integrated titaniumimplant, connected through an

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opening (stoma) in the residuallimb to an external prostheticlimb.

The procedure requires twooperations. The first involvesthe insertion of titaniumimplants into the bone and,often, extensive soft-tissuerevision. The second stage,around six to eight weeks later,includes the refinement of thestoma and the attachment of thehardware that connects theimplant to the externalprosthetic limb. Gradually, boneand muscle begin to grow aroundthe implanted titanium on thebone end, creating a functionalbionic limb. The externalprosthesis can be easily attachedand removed from the abumentwithin a few seconds. Acontinuing development in thefield of OI is the introductionof products that use a porousmetal construction, such astitanium foam. Traditional OIdesigns intended for the femurwere not successful when appliedto the tibia as the proximaltibial bone structure is highlyspongy. However, with thedevelopment of titanium foamtechnology the application of OIhas now been expanded totranstibial amputees.

Mind-controlled bionic limbsThese are prostheses that canbe integrated with bodytissues, including the nervoussystem. They are highlyadvanced, able to respond tocommands from the centralnervous system and thereforeto more closely replicate

normal movement andfunctionality, while alsoinstantly triggering the desiredmovement with less ‘lag time’.There are several differentprocedures and technologiescurrently in the research anddevelopment phase.

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The illustration of OI arms

Source: An osseointegrated human-machine gateway for long-term sensory feedback and motor control of artificial limbs

Targeted muscle reinnervationA surgery called targetedmuscle reinnervation usesnerves remaining after anamputation, and the sameimpulses from the brain thatonce controlled flesh andblood, to control anartificial limb. The surgeryreattaches nerves that controlthe joints from the missingpart of the limb into muscletissue in the residual limb toallow a more natural thoughtprocess and control theprosthesis the same way asmyoelectric control.Effectively, the brainimpulses are linked to acomputer in the prosthesisthat directs motors to movethe limb. The procedureinvolved numerous steps overmany months.

The Drawbacks ofBionic Arm Many functional and imitativebionic arms are expensive, andthey have certain requirementsabout the recipient's physicalcondition so that it is noteasy for amputees to tailor asuitable bionic arm tothemselves. Occurrence andseverity of adverse eventswith bone-anchored bionic

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prostheses are yet to be fullyresolved. Bionic limbs canpotentially cause issues withimplant stability, bone fracture,breakage of the implant parts,and infection. All these adverseevents have several commonnegative effects, for instance,pain and disruption to thelifestyle because of thelimitation to the usage of theprosthesis for a prolongedduration.

The battery and motor inside themyoelectric arm make it heavy, itis expensive, and there is aslight time delay between theuser sending a command and thecomputer processing that commandand turning it into action. Adisadvantage of OI arms is thatthe area where the implant entersthe skin (called the “stoma”) hasto be cleaned twice daily withsoap and water. This iscomparable with brushing teeth.In some cases, the skin aroundthe stoma may become irritated.OI is an advanced technology thatthe recipients of it report thatit feels close to a real limb,but it can be costly (generallyover $80,000) and unsuitable formany types of an amputee.

Overuse syndrome is a commonproblem of bionic limbrecipients, where additionaland atypical amounts of time

and pressure are borne downthrough the intact limb. Overtime, this can and will causeearly degeneration of thelower back, hip, knee andankle resulting in discomfortand other complications. Thisbecomes even more important ifthere are injuries to theintact limb, which make iteven more critical that theprosthesis be designed toevenly bear the load andsmooth out every step inindividuals’ gait. Moreover,friction rashes are a frequentside-effect of wearing aprosthesis. When sweatdisrupts close liner adherenceto the skin, the sweat soakedouter layers of the skin willeasily abrade and develop arash or blisters, as early asafter a few hours. It may takedays for a rash or blisters toheal, during which theprosthesis should not be worn.Sweat may also lead todisruption of myoelectriccontrol as early as 10 mininto intensive manual labors.

Future OutlookAdvances have made theseartificial limbs morepractical and intuitive, buteven the most state‐of‐the-artprostheses cannot yet

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replicate the full functionalityof natural limbs. There is stillhuge room for improvement inthese technologies in the future.AI and machine learningtechnologies are incorporatedinto the new mind-controlledbionic arms. Currently, manyadvanced technologies are in thelaboratory stage and looking formarketing transitions, and thebiggest hurdle is its cost. Worldwide, access to prostheticcare is limited. The World HealthOrganization estimates that 30million people are in need ofprosthetic and orthotic devices —yet more than 75 percent ofdeveloping countries do not havea prosthetics and orthoticstraining program in place, oftenleading to poorer clinicalcoverage of patients. Even in theU.S, only 1/4 of upper-limbamputees use prosthetics.Applying 3D printing technologyto the manufacturing of bionicarms is a feasible way to solvethe cost problem in the future.

Technical development of bionicarms in the futureSeveral different procedures andtechnologies of mind-controlledbionic limbs are currently in theresearch and development phase. Researchers from Iceland havecreated a mind‐controlled

prosthetic leg that usesimplanted myoelectric sensor(IMES) technology. With thisadvanced technology, they nolonger need to think abouttheir movements because theirunconscious reflexes areautomatically converted intomyoelectric impulses thatcontrol their bionicprosthesis. Taking this a stepfurther, in 2015 researchersat the US Defense AdvancedResearch Projects Agency(DARPA) announced that theyhad given a paralyzed man theability to feel physicalsensations via a prostheticrobotic hand that had wiresdirectly connected to hisbrain.

The robotic arm beingdeveloped at Johns Hopkins APLhas 26 joints and 'load cells'in each fingertip to detectforce and the torque appliedto each knuckle. Sensors givefeedback on temperature andvibration and collect the datato mimic what the human arm isable to detect. Its responseto thought is proximate to anormal arm. The deviceattaches to the user via anosseointegration implant, asmall post that goes into thebone and protrudes through theskin. That orientation allows

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the device to clamp directly ontothe skeletal system, giving theuser a more natural understandingof how the limb is moving. Byattaching to the bone, theperception of weight is alsolower than traditional externalattachments.

A solution to decrease cost: 3Dprinting in biotic armsThe 3D printing design isbeginning to help create bionicarms that are a perfect custom-fit for the wear at a moreaffordable price. Driven by adeep desire to create affordablesolutions for people withdisabilities, the team ‘eBionics’of teenagers from Skopje, NorthMacedonia won the GlobalGeneration Unlimited Challenge2019/20 prize by developing a 3D-printed bionic arm 30 timescheaper than existingprosthetics. Their ‘VenusArm’ wasentirely 3D printed and usedmuscle sensors to allow forflexible movement that helped theuser in everyday life. In theirintroductory video, a young womanis shown using the bionic arm tooperate a sewing machine and evento drive a car. They also used animpression mold to create auniversal socket, which means itwill fit anyone, even growingchildren.

The Latest Technology andMaterials to Help Amputeeshttps://www.scheckandsiress.com/products-services/bionic-limbs-prosthetic-technology/

3D printing will make a greatcontribution to themanufacturing of bionic armsin the future. Prostheses cannow be created withanatomically correct shapesthat mirror the form of thewearer and can incorporatedetails such as accurate skincolor, freckles, birthmarks,hair, veins, tattoos,fingerprints, and fingernails.These life-like creations canbe made from PVC or a range ofsilicones and cover theprosthetic limb using avariety of methods, such asadhesive, stretchable skins,suction, form-fitting, or askin sleeve. In the future,bionic limbs will become moreand more common to providehigh-quality and inexpensiveservices for individuals inneed.

References

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Case-study of a user-drivenprosthetic arm design: bionichand versus customized body-powered technology in a highlydemanding work environmenthttps://www.ncbi.nlm.nih.gov/pmc/articles/PMC5751817/Teenagers develop 3D-printedbionic arm 30 times cheaperthan existing prostheticshttps://www.generationunlimited.org/stories/teenagers-develop-3d-printed-bionic-arm-30-times-cheaper-existing-prostheticsBionic limbshttps://www.science.org.au/curious/people-medicine/bionic-limbshe complete guide from theprosthetic experts at MCOPhttps://mcopro.com/blog/resources/arm-hand-prosthetics/Common Prosthetic Issueshttps://mcopro.com/amputee-resources/common-prosthetic-issues/The future of bionic limbshttps://researchfeatures.com/future-bionic-limbs/Facts About Limb Losshttps://www.sralab.org/research/labs/bionic-medicine/news/facts-about-limb-loss

How AI and machine learningare changing prostheticshttps://www.medtechdive.com/news/how-ai-and-machine-learning-are-changing-prosthetics/550788/Control Strategies andPerformance Assessment ofUpper-Limb TMR Prostheses: AReviewhttps://pubmed.ncbi.nlm.nih.gov/33802231/

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Bionic Arms