Brussels, 06 Jul 2006
UK researchers have made a breakthrough in the design of prosthetic appendages.
False limbs have traditionally been limited in use because they have no firm contact to the skeleton, and therefore are not as perfect as they could be. This can give rise to pressure sores and pain through rubbing. When prosthetic limbs have been physically attached, the 'fit' has been improved, but there is a risk of infection.
'To develop skin- penetrating, bone-anchored amputation prostheses, can lead to opportunist invasion by microorganisms and subsequent infection, which can jeopardize the life of the individual,' reads a new paper, published in the Journal of Anatomy, outlining the new designs. The researchers looked to nature for an adequate solution to the problem, examining deer antlers.
'Antlers are subject to extreme loading during the rutting season and yet the skin-bone barrier remains intact,' reads the paper, published in the Journal of Anatomy.
The new technique secures a titanium rod directly to the bone. Prosthetic limbs can then be attached to the rod. The Intraosseous Transcutaneous Amputation Prosthesis (ITAP) allows the skin to form a 'tight seal between the implant and the host tissues, for use in amputation prosthetics,' eliminating the chances of infection.
The team worked in conjunction with company Stanmore Implants to test the new designs. Dr Paul Unwin, Managing Director of Stanmore Implants Worldwide, spoke to the BBC about the new technology. 'The mobility of tissue is a big factor; you don't want the tissue to rip away from the piece of metal, so you need a structure under the skin that will allow the dermal tissues to attach into the metal,' he said.
'What we had seen in the deer antlers was that it is very much to do with the structure and shape of the bone, and the porosity of the bone,' he said. 'The tissue attaches in with long fibres, and it is like anchors attaching directly into it.'
These features give the antler both its stability and its resistance to infection, and have been transferred to the new implants. Tests on fingers and thumbs have been encouraging, and tests on larger limbs will begin shortly. Assuming they will be successful, the team believes that commercial applications could begin in five years, giving those who have lost limbs almost completely natural movement. Ongoing research into muscular control, also at UCL, in conjunction with this technology could soon give rise to the first 'bionic' limbs.
UCL Bio-Medical Engineering department
An account of the new developments in the Journal of Anatomy