Simulated Fingers & Hands

Image Sources: http://bme240.eng.uci.edu/students/10s/slam5/Pictures/Pressure%202.jpghttp://cdn-static.zdnet.com/i/story/60/20/001213/wrobo02.jpghttp://2.bp.blogspot.com/-2jwXtRGp-7o/UOWuHFjigdI/AAAAAAAAAOc/ITFsCK9uCZI/s1600/isella_robot_arm1.jpghttp://i0.wp.com/www.baltimorefishbowl.com/wp-content/uploads/2013/01/johns_hopkins_APL_prosthetic_arm.jpeg?resize=500%2C357

By: NISCHAL RAI

Biomechatronics An applied interdisciplinary science that integrates

mechanical elements, electronics and parts of biological organisms

Includes aspects of biology, mechanics and electronics

Incorporates robotics and neuroscience Aims to develop devices that interact with human

muscle, skeleton and nervous system Simulated fingers and hands are a branch of

Biomechtronics

History First recorded illustration of prosthetic replacement appears in

the Rig-Veda, a religious text written in Sanskrit, compiled between 3,500 and 1,800 B.C. in India.[1]

In 1504, the Iron Hand of knight Götz von Berlichingen was constructed by an armourer and with the help of gearwheels the fingers could be revolved and fixed at a certain position.[2]

In 1909, D. W. Dorrance invented a split hook that was anchored to the opposite shoulder and could be opened with a strap across the back and closed by rubber bands.[3]

In 1915, Sauerbruch's hand was devised by a German surgeon Ernst Ferdinand Sauerbruch in collaboration with Aurel Stodola Slovak physicist, turbine engineer and professor of mechanics which was controlled and powered directly from surgically prepared muscles of the residual limb.[4]

Fig: The Iron Hand of Götz von Berlichingen

Fig: Sauerbruch’s hand

Image Sources: http://www.maximumpc.com/files/u134761/gotz.jpghttp://www.deutsches-museum.de/fileadmin/Content/TRASH/sauerbruchhand_weiss.jpg

Importance ofSimulated Fingers & Hands

Helps regain human motor control that was lost or impaired by trauma, disease or birth defects.

Minimises the disadvantages of disabilities.

Allows disabled people to become more independent.

Image Sources: http://www.wired.com/images_blogs/gadgetlab/2009/11/arms_2a.jpghttp://www.touchbionics.com/media/56932/i-limb_digits_food_prep.jpg

Types of Simulated Fingers & Hands

Mind-controlled: movement of the prosthetic is driven solely by the electrical impulses of the brain

Myoelectric: detects electrical changes in the muscles of the stump and converts them into movements

Body-powered/Cable-controlled: controlled by cables connecting the prosthetic limbs elsewhere on the body

Hybrid: combines two types of control in the same prosthesis

Image Source: http://images.gizmag.com/inline/thought_controlled_permanent_prosthetic_arm-2.jpg

MechanismSimple Body-powered Prosthetic Arm

Image and information sources: http://rehabeasy.blogspot.co.uk/2008/10/bionic-arm-mechanism.htmlhttp://www.wired.com/wiredscience/2012/03/ff_prosthetics/all/?pid=3424&viewall=true

Extending the arm or flexing the shoulder pulls a cable attached to a harness on the user’s back.

As the cable tightens, it opens a split hook at the end of the arm and reversing the move closes the hook.

This prosthetic arm also provides a sensory feedback-force which gets felt by the user’s body.

Mind-controlled Prosthetic Arm

Materials used in Simulated Hands &

Fingers In the past iron, steel, copper and wood were the

major materials used.

At the present, following materials used serve specific purposes: Titanium: lightweight, provides longer life and

durability Aluminium: lightweight and durable Thermoplastics sockets: lightweight and give

prosthesis recipients extended comfort at the site the prosthesis is fitted

Carbon fibre: forms lightweight pylon and gives amputees a sense of life in their limbs

Recent Innovations

A company called ‘i-limb’ has a product called the ‘i-digits’ which provide personalized electronic digits for people who have loss up to five fingers.

However, the patient must pass a selection criteria to be considered.

Each prosthetic is unique to fit the hand of the patient. It is battery powered. The interface material is silicone to avoid damage done to the

skin and tissue. The ‘i-digit’ is controlled using myoelectrodes or force-sensing

resistors (FSR's).[11] The electrodes can sense muscle contraction. This contraction is filtered and processed to tell the fingers to open or close.[11]

The prosthetic can be covered with a silicon material to match the colour and appearance of the patient's skin.

i-limb

Image source: http://www.touchbionics.com/media/2197/i-limb-digits_coverings_match2.jpg

Recent Innovations

Developed by ‘Didrick Material’.

Unlike the ‘i-digit’ it is not electronic and does not require a power source.[9]

Made from surgical steel and is lightweight

Are able to bend naturally with the movements from residual fingers.[9]

It is body powered meaning that the movements of the prosthetic fingers are determined by the movements of the residual finger

This makes it user friendly and does not require any training

Each ‘x finger’ is independent which allows for more articulation control, claimed to be able to grip golf clubs and play musical instruments.[10]

A silicone cover can be applied to match the appearance of the user’s skin

Costs are estimated to be $1000 per digit.[10]

X-Finger

Image Sources: http://www.wired.com/images/article/full/2007/07/xfinger_full.jpghttp://www.asme.org/getmedia/6129d14e-06ff-4e39-84fd-031af5689cf1/everyday_prosthetic_fingers-Bioengineering-hero.jpg.aspx?width=680

Issue Aid vs. Enhancement:

“Bionic hand for 'elective amputation' patient”[5]

-Neil Bowdler, BBC News If people with minor damages to their hands undergo amputation and replace their

hands with simulated hands for better function today, then will people with healthy hands undergo amputation if technologically advanced simulated hands with extraordinary features are developed in the future? Will it devalue natural hands and life?

Image Source: http://news.bbcimg.co.uk/media/images/52822000/jpg/_52822586_jex_1049675_de27-1.jpg

Cost Transradial, below the elbow, prostheses cost between £4,000 and £5,500.[6]

Transhumeral, below the shoulder, prostheses cost between £6,500 and £10,000.[6]

Body-powered prostheses cost approximately £4,500 and Myoelectric prostheses cost approximately £10,000.[7]

Repair costs are approximately £500 annually and the prostheses need replacing every 4 to 5 years.[8]

References [1]VANDERWERKER, E.E., 2013. A Brief Review of the History of Amputations and Prostheses. ICIB 1976 Vol. 15, Num. 5, p.15-16. Retrieved April

12, 2013, from http://www.acpoc.org/library/1976_05_015.asp

[2]Prosthetic Arm through the Ages. 2013. Retrieved April 12, 2013 from http://www.medica-tradefair.com/cipp/md_medica/custom/pub/content,oid,23173/lang,2/ticket,g_u_e_s_t/~/Prosthetic_Arms_through_the_Ages.html

[3]Made How: Artificial Limb. 2013. Retrieved April 12, 2013, from http://www.madehow.com/Volume-1/Artificial-Limb.html

[4]Whonamedit?: Sauerbruch’s hand. 2013. Retrieved April 12, 2013, from http://www.whonamedit.com/synd.cfm/3966.html

[5]BOWDLER, N., 2011. Bionic hand for ‘elective amputation’ patient. BBC News Science & Environment. Retrieved April 12, 2013, from http://www.bbc.co.uk/news/science-environment-13273348

[6]SWEENEY, E., 2005. Cost of prosthetics stirs debate. The Boston Globe. Retrieved April 12, 2013, from http://www.boston.com/business/globe/articles/2005/07/05/cost_of_prosthetics_stirs_debate/

[7]BAGLEY, A., JAMES, M., SELF, B.P., COLEMAN R. & DENARO B., 2013. DETERMINING USAGE OF A JUVENILE MYOELECTRIC PROSTHETIC ARM. ACPOC News 2002 Vol. 8, Num. 4, p.17-18, 20, 22, 24, 25. Retrieved April 12, 2013, from http://www.acpoc.org/library/2002_04_017.asp

[8]MARTIN, C.W., 2011. Upper Limb Prostheses. WorkSafeBC Evidence-Based Practice Group, p. 6. Retrieved April 12, 2013, from http://www.worksafebc.com/health_care_providers/Assets/PDF/UpperLimbProstheses2011.pdf

[9]‘X Fingers prosthetic designed to replace lost digits’- cnet retrieved 21/04/13 at http://news.cnet.com/8301-17938_105-20071697-1/x-fingers-prosthetic-designed-to-replace-lost-digits/

[10]‘Mechanical Fingers Give Strength, Speed to Amputees’- Wired retrieved 21/04/13 at http://www.wired.com/gadgets/miscellaneous/news/2007/07/xfinger

[11]Touch Bionics, retrieved 21/04/13 at http://www.touchbionics.com/products/active-prostheses/i-limb-digits/technical-information/