Reconstructive surgery and bionic limbs

7th December 2011

 

It’s with great heart that I read of the massive improvement in the quality of life offered to Matthew Newbury with one of the cutting edge advances in lower limb prosthetics. The Evening Standard covered it here

Here it seems, for the right money, a limb which is light yet sturdy and has the intelligence to sense movement and terrain can liberate an amputee from lumbering, weighty and painful alternatives. Many of us will have patients for whom this technology would be wonderful to offer but resources are such that private funding, personal injury settlements or generous benefactors are usually required to access this modern kit. .

What is the role of the plastic surgeon in restoring function to those with these severe injuries? Now more than ever we are very much part of the rehabilitation team in making early decisions about limb salvage procedures, maximising the viability of tissue threatened with early wound care, removal of devitalised and contaminate tissues (debridement) and release of the tight fibrous tissue encircling swelling muscles (fasciotomies) to relieve tissue pressure (compartment syndrome) and enable blood to flow – these are just the basics that require scrupulous attention to detail. 

The range of causes of limb injury vary from meningococcal disease and high velocity road traffic accidents to gunshot wounds. Our battlefield colleagues and those involved in the rehabilitation of injured servicemen sadly have a new wealth of experience in this area. Striking the balance between officiously striving to maintain a limb which is likely to be stiff, painful and clumsy may be made easier if assurances that access to these latest generation limbs was guaranteed.  

Decisions about levels of amputations require consultation with rehabilitation colleagues and inventive procedures with free tissue transfer to provide good quality cover, thereby avoiding loss of a joint. The photos of Mr Newbury show his remaining leg to have a number of skin grafts over presumed fasciotomy wounds and it is likely that this “good” leg has a degree of lack of mobility and function. In this example even more benefit will come from a “bionic” leg as it will enable more sharing of the load of walking, which might otherwise have been born by the “good” leg, adding to its stresses and strains.

Modern prosthetic limb manufacture is an extraordinary growth industry with sophistication at every level from bespoke cup/socket design to ensure a comfortable and accurate fit whatever the contour irregularities, supportive pylons in modern lightweight materials such as carbon fibre and now internal mechanisms which have gyroscopic devices and sensors. These sensors can send data about the weight being put through the joint, the movement of the leg and the angles at which it is moving sufficiently frequently that it can anticipate what will happen next, working in real time to respond to the wearer. So now we can have a joint with sufficient “proprioception” to move just like a real knee.  

Other advances in limb technology include approaches such as targeted muscle reinnervation, where nerves which used to control a muscle are redirected to an available muscle (for example, on the chest in the case of an upper limb amputation) and then sensors placed in association with that muscle send impulses to the limb to instruct it to do what the original target muscle used to do. It won’t be long before impulses directly from the severed nerves will be picked up in a useful enough fashion that a device will be made to work by just sending the usual messages to a now missing part.
 

 

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