Classifications

• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B5/00—Measuring for diagnostic purposes; Identification of persons
  • A61B5/45—For evaluating or diagnosing the musculoskeletal system or teeth
  • A61B5/4519—Muscles
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B5/00—Measuring for diagnostic purposes; Identification of persons
  • A61B5/103—Detecting, measuring or recording devices for testing the shape, pattern, colour, size or movement of the body or parts thereof, for diagnostic purposes
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B5/00—Measuring for diagnostic purposes; Identification of persons
  • A61B5/103—Detecting, measuring or recording devices for testing the shape, pattern, colour, size or movement of the body or parts thereof, for diagnostic purposes
  • A61B5/11—Measuring movement of the entire body or parts thereof, e.g. head or hand tremor, mobility of a limb
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B5/00—Measuring for diagnostic purposes; Identification of persons
  • A61B5/45—For evaluating or diagnosing the musculoskeletal system or teeth
  • A61B5/4528—Joints
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B9/00—Instruments for examination by percussion; Pleximeters
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B9/00—Instruments for examination by percussion; Pleximeters
  • A61B9/005—Electric apparatus for detecting reflex action, e.g. monitoring depth of anaesthesia

Definitions

• This invention relates to methods of and appa ⁇ ratus for investigating or examining muscles and/or joints.
• apparatus for investigating muscles and/or joints comprising a pulse-generating device to be positioned in contact with a body under investigation to apply a force pulse or pulses to the body, first sensing means providing a first output representative of the reaction of the body to the force of the applied pulse or pulses, second sensing means providing a second output representative of the acceleration of the body resulting from the applied pulse or pulses, and pro ⁇ cessing means arranged to use said first and second outputs to provide a third output which is based upon a combination of the information in both first and second outputs and which is representative of muscle tone and/or joint yield.
• the first sensing means comprises a force transducer providing an electrical waveform output
• the second sensing means comprises an accel ⁇ erometer providing an electrical waveform output
• the pulse-generating device produces a pulse having a slowly rising leading edge.
• the processing means comprises computer means arranged to divide one of said first and second outputs by the other, thereby to produce said third output.
• Fig. 1 is a block schematic diagram of a first embodiment of apparatus in accordance with the invention
• Fig. 2 is a schematic illustrationof an alter- native system for generating the force pulses
• Fig. 3 is a schematic diagram of a further system for generating the force pulses
• Fig. 4 is a schematic diagram illustrating an alternative embodiment in which the transducers are separated
• Fig. 5 is a waveform diagram showing typical force and acceleration waveforms when the apparatus of the present invention is used on soft tissue.
• Fig. 6 is an equivalent waveform diagram showing typical force and acceleration waveforms when the apparatus of the present invention is used on hard muscle or joints.
• the apparatus is shown as comprising a sensing "gun” or probe which is indicated generally at 10.
• the sensing gun shown in the drawing is designed to be hand-held during use.
• the gun comprises a body portion 12 which serves as a housing for a spring-loaded piston 13 attached to a piston rod 14 which functions as a plunger.
• the piston/piston rod assembly is provided with latch means within the housing 12 so that the piston and piston rod can be "cocked” for subsequent release by the actuation of a trigger mech ⁇ anism 16.
• the plunger 14 In response to actuation of the trigger mechanism 16 the plunger 14 is displaced axially out ⁇ wardly of the housing 12 with a stroke which is pre ⁇ ferably of the order of k inch (6mm).
• the force pulse which is generated by the act ⁇ uation of the plunger 14 should advantageously have a slowly rising pulse waveform, and is preferably part of a sinusoidal waveform.
• the force pulse generated by the plunger 14 preferably has a duration of about 0.2 sec- onds and a peak amplitude values of the order of 1 Newton.
• these figures are to be considered as examples only and the force pulse parameters may vary from the figures given and may indeed be selected in dependence upon the particular patient or upon the particular tissues or joints to be examined. In carrying out the investigation in accordance with the invention one is seeking to determine the compliance of tissue and the yield of joints. A force pulse with a slowly rising leading edge is considered to be most advantageous for this purpose. Additionally, the force pulse amplitude should not be too great, otherwise one creates such dis ⁇ tortion within the body that muscle mobility and joint yield cannot readily be determined.
• a force transducer 18 Adjacent to the end of the gun remote from the end of the plunger 14 which contacts the patient, there is provided a force transducer 18 which measures the force exerted by the plunger against the body as the plunger moves forward. This of course is representative of the reaction force exerted by the body on the end of the plunger.
• the force transducer 18 may comprise a load cell, a strain guage, or other transducer mechanism appropriate to measure forces of the magnitude involved here.
• the transducer 18 may be a mini ⁇ ature quartz force transducer suitable for measuring dynamic and quasistatic forces. The force to be re ⁇ corded acts on the quartz element within the transducer.
• the longitudinal piezoelectric effect which is produced causes an elec ⁇ trostatic charge to be generated in the quartz element.
• the transducer 18 is connected by an output lead 20a to a charge amplifier 22a.
• the output signals from the force transducer 18 are transformed into proportional output voltages in the charge amplifier 22a.
• the accelerometer 24 is preferably a miniature konic accelerometer, although other forms of accelerometer could be used as alternatives.
• An accel ⁇ erometer having a low resonant frequency is preferred. With force pulses having parameters of the order of magnitude referred to above, accelerations of the order of 1 g will be generated.
• the accelerometer 24 is connected by an output cable 20b to a second charge amplifier 22b where the output signal from the accel- erometer is similarly transformed into a proportional output voltage.
• the outputs of the charge amplifiers 22a and 22b are fed to an analogue-to-digital converter 26, the digital output of which is fed to a computer 28.
• the computer 28 can incorporate or be connected to any appropriate measuring /recording/display apparatus or instruments 29.
• the sensing gun or probe 10 is preferably pro ⁇ vided with a depth control adjustment mechanism, in ⁇ dicated schematically at 30' in Fig. 1, whereby the axial stroke of the piston rod 14 can be adjusted.
• the force transducer 18 and accelerometer 24 may alternatively be positioned on the plunger 14 itself, externally of the housing, instead of at the trigger end of the gun ' .
• the body-contact end of the plunger 14 may be provided, if appropriate, with a resilient end cap, for example of rubber.
• the accelerometer 24 may be replaced by any equivalent device which will satisfactorily measure the acceleration and damping waveforms generated by the reaction of the muscle and/or joint to the imposed force pulse.
• An optical detector mechanism could for example be used. It should be understood that the reference herein to "acceleration" includes also deceleration, as occurs when damping takes place.
• sensing gun shown in Fig. 1 is designed to be hand-held against the patient undergoing examination, one can alternatively arrange for the gun to be fixed or clamped in position so that one avoids any errors arising from movement of the operator. If the gun is to be a hand-held instrument then it should be heavy in order to increase its inertia.
• Fig. 2 shows an alternative to the trigger mech ⁇ anism 16 for generating the force pulses.
• a cam 30 is controlled as to its rotation by a spring 32.
• cam 30 is mounted on a central shaft 34.
• a cam follower 36 in the form of a tappet is positioned so that it is struck by the cam 30 in its rotational movement. Rotation of the cam follower 36 initiates a linear dis- placement of the plunger 14.
• the force pulse waveform can thus be chosen by suitable choice of the cam profile and of the force of the spring 32 which determines the speed of rotation of the cam. If the cam 30 is detach ⁇ able, one can select any one of a plurality of cams. A double-acting cam can be used to cancel out kickback of the plunger. By providing the individual cams with different profiles one can select the force pulse shapes, depending upon the condition of the patient and the nature of the tissues and/or joints to be ban- gated.
• Fig. 3 shows yet another method of generating the necessary force pulse.
• the plunger 14 is displaced by the action of a solenoid mechanism 38 which is driven by an output waveform from a waveform generator 40.
• the waveform generator 40 may be triggered to produce an output initiating pulse by operation of a push-button 42.
• Fig. 4 is a diagrammatic representation of an alternative embodiment, in which the accelerometer 24 is not mounted on the gun 10 but is separate from it. With this arrangement the force transducer 18 which is still coupled to the plunger 14 remains as part of the sensing gun, but the accelerometer 24 is in the form of a separate unit which can be positioned as appropriate on the skin of the patient. When the plunger is actu ⁇ ated, the force pulse is transmitted through the tissue and/or joint and the damping wave is picked up by the accelerometer 24.
• the arrangement can be such that the plunger 14 and accelerometer 24 are physically linked so that the two are moved over the patient as one, i.e. the plunger 14 and accelerometer 24 are maintained a con ⁇ stant distance apart, or alternatively the accelerometer 24 can be in the form of a roving probe which the operator can position as he wishes.
• the sensing gun or probe 10 is placed against a muscle and/or joint to be examined. This is so whether the gun is hand-held or is clamped in a fixed position.
• the firing of the gun will cause the piston rod 14 to move axially relative to the housing and thus to impart a single shock pulse to the patient.
• This force pulse preferably has a slowly rising leading edge and is preferably substantially sinusoidal in shape. Because the plunger 14 is in contact with the body surface, the body will react to the pulse.
• the force transducer 18 will measure the force imposed on the body and its output on lead 20a will represent the force pulse waveform, as shown at 50a and 50b in Figs. 5 and 6.
• the reaction of the body to the force pulse is determined by the accelerometer 24, whether this is monitoring the movement of the plunger
• the output of the accelerometer 24 on lead 20b will thus be an acceleration or damping waveform, for example of the type shown at 52a and 52b in Figs. 5 and 6.
• the reaction of the body modifies the basic force pulse and is what is measured by the force transducer 18; this reaction can thus be thought of as a mobility wave.
• Fig. 5 illustrates typical waveforms when a force pulse is applied to soft tissue
• Fig. 6 shows the equi- valent typical waveforms when the same pulse is applied to "hard" material, such a a joint or a hard muscle.
• the mobility wave 50b falls away from its peak more sharply.
• the accel ⁇ eration or damping wave. 52a, 52b is of substantially different form when one is considering soft tissue as compared with harder material.
• Fig. 5 in the case of soft tissue, there is an initial acceleration of the tissue in the direction away from the plunger 14, followed by an acceleration in the opposite direction, back towards the plunger.
• Fig. 6 in the case of harder material, as shown in Fig. 6, there is little or no initial acceleration in the direction away from the plunger, and the first indication is an accel ⁇ eration of the material in the direction back towards the plunger.
• the waveforms shown in Figs. 5 and 6 are by way of example only and that the actual waveforms in any particular case will vary, depending upon the shape of the generated force pulse, and the nature of the material to which the force pulse is applied.
• An important feature of the present inven ⁇ tion lies in using the computer 28 to produce an output which is based upon the interaction or interrelationship . of the two output waveforms 50 and 52. Analysis of the mobility waveform will give the operator a certain degree of information, and analysis of the damping waveform would also give the operator certain infor- mation. However, in accordance with the present inven- tion, it is use of these two waveforms jointly which • enables the operator to gain more definitive information about the condition of the muscle or joint being invest ⁇ igated. By the use of appropriate programmes in the computer 28, together with an appropriate data base, a comparison is made of two waveforms 50 and 52 and an output is produced which is representative of that comparison.
• an output either graphically, or numerically, or as a display or in some other way which will not only tell the operator the condition of a muscle or joint in relation to a predetermined standard but which can also be used for comparison purposes, for example by monitoring a patient's muscles or joints on a regular basis and comparing the results to indicate the improvement or deterioration in the muscles or joints.
• the present invention also includes other ways of processing the information from those two waveforms in order to produce a single output which is based upon information from both waveforms.
• the apparatus and method of the present inven ⁇ tion can be used not only on humans but also on animals.

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• 1984
  • 1984-12-12 GB GB848431323A patent/GB8431323D0/en active Pending
• 1985
  • 1985-12-11 GB GB08530527A patent/GB2168489B/en not_active Expired
  • 1985-12-11 WO PCT/GB1985/000572 patent/WO1986003393A1/en unknown
  • 1985-12-11 CA CA000497330A patent/CA1270908A/en not_active Expired - Lifetime
  • 1985-12-11 EP EP86900196A patent/EP0204800A1/de not_active Withdrawn

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