A method and a device for recording mechanical oscillations in soft biological tissues

METHOD AND APPARATUS FOR RECORDING SOFT BIOLOGICAL TISSUES - MYOMETER

TECHNICAL FIELD

The invention is within the field of medical technology and is intended for repeated non-invasive monitoring of the mechanical properties of soft biological tissues. The method and device are used to evaluate the effectiveness of massage techniques and the impact of physiotherapeutic procedures on tissues, to quantify the level of pathological processes, to determine the genetic prerequisites of organs, to monitor tissue tone during surgical operations, to evaluate soft tissue status in forensic medicine.

BACKGROUND OF THE INVENTION

The mechanical properties of soft biological tissues are used as a source of information to assess the functional status of tissues and organs for the following reasons.

The intensity of the metabolic processes in biological tissues depends on the influence of the internal and external environment, resulting in a change in the mechanical properties of the tissues.

Physical activity, for example, causes hypertrophy in skeletal muscle, inactivity produces atrophy. Many neurological diseases and traumas result in significant changes in muscle tone. The latter is characterized by muscle stiffness and damping properties. The stiffness depends on the pressure in the muscle, the damping on the elastic properties of the morphological structures of the muscle. The human propulsion apparatus is constructed in such a way that two antagonistic muscle groups are always involved in the rotation of the body part around the joint axis. Agonists exert a motive force on the joint axis, while antagonists are stretched out. What is antagonistic is important for the energy of movement and movement

EE 03374 ΒΙ mechanical energy required for stretching, which in turn is composed of two parts: the resistance force due to the tonic stress of the antagonist and its cross-section, and the resistance due to the damping properties of the antagonist over the same path that depends on the speed of stretching. The tone of the skeletal muscle depends on the intensity of the efferent innervation on the one hand and the cellular tone on the other. Both effects can increase the mechanical stress on the body wraps or fascias. In turn, the elasticity of collagen filaments in the muscle envelopes affects the dissipation capacity of the mechanical energy of biological tissue. Thus, on the one hand, changes in the mechanical properties of biological tissues may be the cause of trauma or pathological processes, but on the other hand, changes in mechanical properties of skeletal muscle may determine the success of surgery, physiotherapeutic procedure, massage, therapeutic or medical effects.

It follows from the above that the mechanical properties of biological tissues contain information on the level of function of the tissues and allow the prediction of the consequences of altering the mechanical properties of biological tissues.

Attempts have been made to determine the mechanical properties of soft biological tissues by various devices and methods. A more general disadvantage of those used to date is that the methods themselves alter the mechanical properties of the tissue under study, or the duration of the measurement process is so great that the living entity being measured can intentionally alter the mechanical properties of the tissue during measurement. For example, a device for measuring muscle tone, comprising two cuffs, one of which is fitted with an accelerometer and the other is subjected to a mechanical influence (NL certificate no.

150573, A 61B 5/05, Fedorov VL, Galysev FM, 1961). In this case, the attachment of the cuffs to the muscle causes an increase in blood flow and, consequently, a change in muscle tone. The measurement depends on how long the cuffs have been on the muscle.

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Of the known methods, the method closest to the present invention for measuring the mechanical properties of soft biological tissues is the so-called. a method of quenching oscillations, the nature of which is to exert an external mechanical influence on biological tissue as a shock and to record the mechanical response of biological tissue in the form of an oscillation graph (FennW.O., Garwey

PHJClin., Invest. 1934, 13, p. 383-397; Vajn A., Method of zatuhajuscih kolebanij pri diagnostike funcionalnogo capitalization skeletnyh mysc. Sb. Nuacnyh trudov. Metody vibracionnoj diagnostiki reologiceskih harakteristik mjagkih materialov i biologiceskih tkanej.- Gorky, 1989, s. 116125).

Several devices have been constructed to implement the extinguishing oscillation method, but their construction has not allowed for metrologically correct results. The major drawbacks have been the impracticality of the technique of mechanically acting on biological tissue and the disadvantages of recording the mechanical response of biological tissue. The self-oscillation plot of biological tissue obtained in this way contains information about either the elasticity of the measuring device itself, or the signal is too weak to obtain metrologically correct characteristics of the mechanical properties of biological tissues.

A method and apparatus for immediate non-invasive monitoring of instantaneous fluctuations in viscoelasticity properties of living tissue is known (U.S. Patent No. 4,580,574, A

61 B 10/00, B.Gavish, 1986) using ultrasound. A device for measuring the mechanical properties of soft biological tissues is known (U.S. Pat. No. 1517939, A 61 B 5/10, Godin EA, Cernys VA and Stengold ES, 1988).

A common disadvantage of the foregoing is that (a) the patient may intentionally change the tone of the muscle during the measurement, since the patient is fixed to the measuring apparatus during the measurement procedure;

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(b) the installation of peripheral biological tissues in the apparatus limits the possibilities for testing; (c) the repeatability of the measurements is of low accuracy.

Of the known devices, the closest embodiment of the present invention is a device for measuring the biomechanical characteristics of biological tissues (NL Certificate No.

782 537, A 61 B 5/05, G 01 N 3/30, A.Vain, L.-H.Humal,

1992). Said device consists of a handle body 10 on which is mounted a rotatable two-lever arm with two electromechanical transducers and a wheel-shaped impact nozzle at one end and the impact nozzle actuator at its other end. The device is provided with an elastic member disposed between the housing and the two-lever lever and a recorder.

The disadvantage of the prototype is, firstly, the presence of an elastic element, which limits the recording of the eigenvalues ​​of the biological tissue below the oscillation frequency of the elastic element and complicates signal processing, thereby reducing the accuracy of the measurement results. It is also difficult to find a resilient element with stable mechanical properties in the construction of the device which retains its mechanical properties over a longer period of time.

Secondly, when using a resilient member, it is important to what extent the resilient member is deformed prior to the mechanical impulse given by the impact nozzle actuator. If the deformation of the elastic member is small and there is also a small force to force the impactor against biological tissue, the relatively high impulse impulse drive impulse may lose contact with the biological tissue under investigation after disengaging the impactor drive and analysis of such a graph will give false results. Third, it has been found that at relatively high compressive forces of the elastic member, biological tissue is not followed by significant deformation or oscillation of the tissue after the impulse drive pulse.

EE 03374 B1 After disengaging the impactor drive after impact. In addition, at high compressive forces, the creep and relaxation properties of biological tissues complicate the measurement procedure and reduce measurement accuracy.

SUMMARY OF THE INVENTION

The object of the present invention is to provide a method and apparatus for recording soft biological tissue self-oscillation, wherein the resulting bio-tissue self-oscillation graph allows calculating mechanical properties of biological tissue, improving accuracy of the measuring process, The invention enables soft biological tissue monitoring to be performed repeatedly, non-interferingly and non-invasively.

The essence of the method contemplated is to apply an external mechanical impact to the biological tissue by means of a punch, and to record the mechanical response of the biological tissue in the form of an oscillation graph. However, prior to exerting mechanical impact on the biological tissue with a percussion tip, in contrast to known techniques, a planar means of affixing a band marker to the target area of ​​the biological tissue and securing the perforator to the biological tissue without damaging the biological tissue. The impact nozzle is then rigidly connected to said planar means for producing a rigid mechanical impact and for recording the mechanical response of biological tissue.

A corresponding device for recording soft biological tissue self-oscillation - myometer - includes an additional rigid planar means for marking the biological tissue study area and for rigid and permanent attachment of the impact tip to the tissue without damaging the biological tissue.

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The length of the impact nozzle is variable at its constant weight, for example by means of a bayonet joint.

LIST OF DRAWINGS

FIG. 1 - Soft biological tissue oscillation graph;

FIG. 2 - device for recording soft biological tissue self-oscillation - myometer.

FIG. 1 hr_t - the point at which the mechanical action of the impactor on the tissue begins by the impactor drive, · t₂ - the impactor actuator is deactivated and the biological tissue begins to oscillate freely;

t₃ - the mechanical action on the impact nozzle by the elastic deformation force of the biological tissue begins;

t₄ - the movement of the percussion tip ends and the second period of oscillation begins;

t_k- operating time of the impactor actuator;

t_d - Duration of first mechanical impact of soft biological tissue;

t \ is the time for recovery of deformation of the first mechanical action of soft biological tissue;

a_x - Maximum acceleration due to mechanical action of soft biological tissue, a₂ - Maximum acceleration of the impact nozzle exit due to mechanical action of soft biological tissue;

v - nozzle speed graph;

s - trajectory trajectory over time;

Δ-s is the static deformation of soft biological tissue induced by the force of the impact force.

The area ABC equals the rate of deformation v of the soft biological tissue_d.

EXAMPLE OF CARRYING OUT THE METHOD

First, palpation determines the measurable region of the biological tissue to be examined, in the case of peripheral muscle

EE 03374 B1, for example, a tendon. Before exerting a mechanical impact on the biological tissue with a percussion tip, a rigid, flat means of marking the target area of ​​the biological tissue with the biological tissue without damaging the biological tissue is applied to the surface of the biological tissue (eg by adhesive, vacuum, etc.). The percussion tip is then rigidly connected to said bandage marker during the time of mechanical action and recording of the mechanical response of the biological tissue. For example, an adhesive, a vacuum or the like is used to rigidly attach the impact tip to the bandage marker. mechanical coupling, a mechanical impulse is applied to the area provided with a communications marker, a single pulse of external force lasting a few milliseconds and terminating with a sudden release (rapid release) of the impact nozzle. After the external force pulse has stopped, the impact tip remains in a rigid connection with the tissue measured through the bandage marker and follows the oscillation of the tissue during recovery. After the elastic deflection of the measuring bandage from the impact tip has finished, it shall be disconnected. To measure the next area to be examined, the impact tip is connected to the next communications marker. The measurement procedure described above is short-term and has no effect on tissue metabolic processes and does not elicit neurological reactions by the subject being measured. After the measurement process, the band markers can be removed.

The soft biological tissue self-oscillation graph obtained in this way contains information that can be used to calculate the parameters of the mechanical properties of the tissue, such as the logarithmic decrement of the period of self-oscillation and the rate of damping of the oscillation.

EXAMPLE OF USE OF THE DEVICE

A device for recording soft biological tissue self-oscillation, FIG. 2, consists of a housing 1 with a handle and a two-lever arm with a rotatable attachment

EE 03374 B1 with electromechanical transducer 3 and shutter 4, electromechanical transducer 5, impact nozzle 6, hinge 7, impact nozzle actuation: solenoid 8 and anchor 9, recorder 10, switch 11 for controlling the measuring process, and means for marking and perforating the region of the biological tissue - communication marker 12.

While holding the device handle, the punch 6 is placed on a bandage 12 attached to a biological tissue. The punch is rigidly connected to the bandage using, for example, adhesive, vacuum, or the like. mechanical coupling. After pressing the switch 11, the shutter 4 is rotated to the electromechanical sensor 5 by rotating the housing of the device. When the shutter 4 closes the electromechanical sensor 5, the solenoid 8 of the electromagnet is energized and the anchor 9 is pulled on the solenoid 8 within a predetermined time, and the impact tip with the bandage is applied to the tissue under investigation. At the end of the tensile time, the actuator of the percussion device is deactivated and the biological tissue together with the bandage marker and the percussion nozzle performs a free extinguishing oscillation depending on the elastic properties of the soft biological tissue under investigation. Self-oscillation is recorded by calculating tissue mechanical as indicated by the recorder 10, an indicator. After switch 11 and which characteristics are pressed numerically, the device goes to the start of measurement and the procedure can be repeated. The measurement procedure can also be controlled by computer. This allows rapid and repeated recording of self-oscillation of biological tissues.

The length of the impact nozzle 6 is variable at its constant weight, for example by means of a bayonet joint.

The measurement results in a quiescent oscillation graph that reflects the short-term (a few milliseconds) deformation (mechanical properties) of biological tissue, followed by the free-oscillatory nature (includes mechanical characteristics such as stiffness and

EE 03374 B1). It takes no more than 0.5 seconds to obtain this graph, after which the measurement can be repeated.

The use of the proposed method and apparatus enables the accuracy of the measuring procedure to be increased by replacing the impact tip of the elastic member used in the prototype with a non-invasive rigid connection in the test area;

- examination of tissue at any position of the object;

expand the field of application by changing the length of the punch and changing its position;

using a large range of soft tissue deformation rates due to rigid attachment of the impact nipple to the test tissue without inducing pain sensation or changes in tissue blood flow, while providing a stable, undistorted, self-warping curve due to continuous contact;

reduce the time required for testing by pre-affixing the bandage markers to the target area to connect the punch; increase the accuracy (repeatability) of measurement results.