The Duke of Cornwall Spinal Treatment Centre in conjunction with the
Department of Plastic Surgery and Department of Medical Physics and Biomedical
Engineering is providing a programme to restore the hand function of
tetraplegics. The programme has two main parts, tendon transfer and functional
electrical stimulation (FES).
When a muscle is paralysed, it is sometimes possible to duplicate its function by using a muscle that is not paralysed. This is done by detaching one end of the non-paralysed muscles tendon from its insertion to the bone and re-attaching it to the tendon of the paralysed muscle. For example, it is common for tetraplegics with spinal cord lesions at C4 or C5 to be able to flex their elbow but not straighten it. In such a case it is possible to use part of the non-paralysed deltoid muscle that extends the arm at the shoulder to provide elbow extension. Similarly, tetraplegics with spinal cord lesions of C6 or C7 who have poor hand function but have active muscles controlling their wrist and elbow can have their grip improved.
Surprisingly, it is not hard to adjust to the new use of the muscles.
Physiotherapy and Occupational therapy is given to help the candidate achieve
the full potential from the tendon transfer. The operations take between one
and four hours and require hospitalisation for one week.
Functional Electrical Stimulation. (FES).
***NB the Freehand program is currently suspended due to commercial difficulties at NeuroControl***
The Duke of Cornwall Spinal Treatment Centre is participating in a trial of the NeuroControl Freehand System for restoration of hand function for people with tetraplegia. The system, which has been developed over the past ten years, was developed at the Case Western Reserve University in Cleveland Ohio, in the USA, is now the subject of an international trial. It is designed to enable people with spinal cord lesions at C5 or C5/6 to achieve basic hand grip by means of electrical stimulation of the paralysed muscles. These subjects would not be suitable candidates for tendon transfer procedures alone.
The system consists of the following parts. Small electrodes are placed on the muscles and linked by cables under the skin to an implanted stimulator, located just below the shoulder. The stimulator is similar to a pace-maker. Power and control signals for the implant are passed through the skin by radio telemetry. The user wears a small transmitter coil against his skin, over the implanted stimulator. Additionally, the user wears a shoulder movement detector on the opposite shoulder. This allows him to open and close his hand by making small movements of his shoulder. The transmitter coil and shoulder movement detector are linked by cables to a control box which is carried on the wheel chair.
Two types of grip are possible. A key grip, used for holding small objects such as a key, fork or pen and a palmar grip for larger objects such as a cup or can. Users of the system are able to perform tasks such as writing with a pen, drinking from a glass, or eating with a fork, without any other aid or modification to the implements. This can significantly increase independence, allowing the user to be left without supervision for longer periods of time. At present there are over one hundred people using the system, eleven here in Salisbury.
Candidates for the system have no voluntary movement in the hand, they will have no wrist movement or weak wrist extension. They must have reasonable upper arm function being able to flex the elbow and have good shoulder movement on both sides. The candidates must be in otherwise good health and psychologically suitable for the procedure. A further requirement is that the paralysed muscles that control the hand can be excited by electrical stimulation. This is tested by using an external electrical stimulator. Candidates must be one year or more post injury.
The implant surgery takes approximately eight hours and the subject is hospitalised for one week.
In addition to the implant, it is common for some subjects to require tendon transfer surgery to augment the action of the implant. In some cases an additional operation is required, prior to implantation for tendon transfer surgery, requiring a similar stay in hospital.
It must be realised that while the subject is recovering from either the tendon transfer or implant operation, they are unable to use their arm, significantly increasing their dependence on carers for a period of several weeks. Candidates are required to perform exercises at home which can be time consuming. Additionally they will have to attend regularly as an outpatient for training and assessment.
The Freehand programme currently susspended due to commercial
dificulties at NeutoControl. We hope to continue this work in one shape or form
in the future but are not able to offer an alternative at the monment. For more
information please contact
Paul Taylor or
Julie Esnouf of the Department of Medical Physics and Biomedical
Engineering, Salisbury District Hospital, Salisbury, Wiltshire, SP2 8BJ, Tel.
01722 429121 / 429065