GB2356934A

GB2356934A - Medical transducer comprising a vacuum held flexible pad with measurement electrodes and strain gauges

Info

Publication number: GB2356934A
Application number: GB9928295A
Authority: GB
Inventors: Michael Parnham Travis
Original assignee: Individual
Current assignee: Individual
Priority date: 1999-12-01
Filing date: 1999-12-01
Publication date: 2001-06-06
Also published as: GB9928295D0

Abstract

A transducer pad combined with electrode connectors to measure movements of the muscle fibres and heart muscle and associated electrical signals generated by those movements. The multi-element design of the transducer pad enables multi-dimensional measurement and comparison. The whole device is retained on the muscle or heart by vacuum, thus avoiding intrusion into the muscle fibres and consequent trauma. Figure 1 provides a typical example and illustrates the component parts.

Description

2356934 MEASUREMENT SYSTEM FOR MUSCLE FIBRE & HEART MUSCLE MOTION AND

ELECTRICAL SIGNALS This invention relates to a measurement system which monitors the motions of muscle fibres, including the heart muscle, and their associated electrical signals.

Measurement of the dynamics of muscle fibres and their electrical signals provides important information to surgeons. Currently the dynamics can be measured by sonomicrometry or through instruments inserted into the muscles, but the former lacks the advantages achieved by direct physical contact and the trauma occasioned by the insertion of the latter can endanger the patient.

According to the present invention there is provided a flexible multielement strain-gauged pad transducer to measure the motions with electrode conductors to measure the corresponding electrical signals of the muscle, on which it is retainedby a vacuum, removing the need for intrusive penetrators such as tines or barbs.

A specific embodiment of the invention will now be described by way of example with reference to the accompanying drawings in which Figure IA shows a typical example of the invention as a three-element annular transducer, the pad of medical rubber, strain gauges for motion, contact electrodes signal conductors and vacuum line all being illustrated; and Figure IB illustrates the side view of the vacuum retention system, strain gauges to monitor motion and the electrical signal conductors.

As illustrated, the invention takes the form of an annular transducer pad 4. During use, the transducer is placed by the surgeon against that part of the muscle or heart which is to be monitored and it is retained there by vacuum applied to the orifice 3 through the vacuum line 7.

By the same application to the muscle or heart, the electrode conductor 2 is placed in position.

Whilst the unit is thus firmly and reliably held in place, natural movements of the muscle induce movement into the medical rubber pad 4, which in turn flexes and stresses the strain gauge bridge, producing an electrical output signal - directly proportional in amplitude and phase to the muscle's motion - which is transmitted along the signal cable 8. The direct electrical signal generated by those same natural movements of the muscle is simultaneously fed through the contact electrodes 2 located on the pad.

The mechanically-generated electrical signal can then be compared with the electrical signal detected by direct muscle contact and the evaluation of both will assist in diagnosing the muscle's condition.

As the three encapsulated strain bridges are wired separately, both individual x, Y and z outputs and summed X + Y + z outputs may be obtained for evaluation.

Q Key to Illustrations The numbered components illustrated in the figures are identified as follows:

1 strain gauges (motion) x, Y & z 2 electrode conductor 3 vacuum orifice 4 annular medical rubber pad terminal pad 6 electrode signal cable 7 vacuum pipe 8 bridge signal cable 9 electrode terminal pad.

Claims

I A multi-element strain-gauged flexible transducer pad to measure axial and radial motions with electrode conductors to measure the corresponding electrical signals of the muscle fibres and heart wall; such transducer pad being retained by a vacuum, removing the need for intrusive penetrations.
2 A multi-element strain-gauged transducer pad as claimed in Claim 1, wherein the elements of the transducer are in the form of encapsulated strain gauges.
3 A multi-element strain-gauged transducer pad as claimed in Claim 1, in which each transducer element is individually addressable to supply separate or surnmed information.
4 A multi-element strain-gauged transducer pad as claimed in Claim 2, whereof the transducer is made from medical rubber at the point of contact with the muscle.
A multi-element strain-gauged transducer as claimed in Claim 1, wherein retention is effected by means of a vacuum applied through vacuum lines to orifices set in the medical rubber pad.
6 A multi-element strain-gauged transducer pad as claimed in Claim 1, whereby both separate and summed data obtained through strain gauge techniques may be compared with data obtained directly from contact electrodes, together providing surgeons with diagnostic information previously not available.