RU2289317C2 - Method for registering biomechanical properties of long tubular bones - Google Patents

Abstract

FIELD: medicine, traumatology, orthopedics.

SUBSTANCE: the present innovation deals with predicting lesions and diseases of long tubular bones. The method enables to study biomechanical properties of bones based upon the analysis of mechanic responses after standard stroke-type diagnostic impact. One should perform a dosed stroke in a certain point of a bone followed by receiving, enhancement and analysis of mechanical responses in other parts of this bone due to wide-strip seismographs followed by the analysis of the parameters obtained by the time of signals appearance, maximal amplitude, duration, frequency and degree of attenuating of mechanical impulse. Moreover, diagnostic sensors should be located along both sides against supposed pathological process, that is both from the opposite side and at the side of stroke impact. Then comes comparative analysis of the signal obtained against ideal exponent to detect the degree of soft tissues impact. The degree of fragments contact in case of fractures should be calculated by the decrease of signal's maximal amplitude obtained from a distant seismograph and, also, by the time and maximal amplitude of reflected signal from the nearest one. Mineral density and homogeneity of bony tissue should be detected according to the alteration in frequency and degree of attenuating of mechanical responses from different seismographs.

EFFECT: higher accuracy of diagnostics.

15 dwg

Description

The invention relates to medicine, namely to traumatology and orthopedics, and can find application in the diagnosis of injuries and diseases of long tubular bones.

A known method for the study of bone tissue based on ultrasonic echoostometry, which consists in installing on the surface of the diagnosed area of the emitter and the receiver-transducer of ultrasonic pulses, receiving, recording ultrasonic pulses and assessing the condition of the bone tissue, the emitter and the receiver-transducer are installed on one side of the diagnosed area , and as a diagnostic parameter take the half-wave duration of the transmitted pulse (RF Patent No. 2071274, A 61 V 8/00, 1997.)

The ultrasonic echoostometry method has a number of disadvantages, including:

- does not provide a sufficiently accurate topical diagnosis of the localization of pathological processes and osteoporosis;

- diagnostic information is largely dependent on the impedance of paraossal tissues;

- ultrasonic vibrations for bone tissue are subthreshold and quickly decay, which does not allow the full extraction of important diagnostic parameters;

- equipment for ultrasound is expensive, cumbersome, requires the presence of a functionalist and specially trained medical personnel, which makes it difficult to use during dynamic observation.

A known method for the diagnosis of degenerative-dystrophic changes in bone tissue based on the determination of the absorption coefficient of x-ray radiation on a computer tomograph (AS USSR No. 1680082 A 61 B 6/00).

The disadvantages of the method are:

- high radiation exposure to the patient and medical personnel;

- duration of the study;

- high energy intensity;

- the high cost of research, requiring the use of sophisticated equipment;

- the need for the presence of radiologists, specially trained medical personnel.

At the same time, it is known that mechanical load is an adequate load for bone tissue, for which it was created evolutionarily, and in pathological processes, the biomechanical properties of bones change primarily, which is effectively used in clinical practice (A.I. Anisimov, 1993). The most sensitive methods of non-invasive osteometry are those that are based on recording the nature of the propagation of sound vibrations in the bone tissue, which allows us to diagnose the biomechanical properties of bones in normal and pathological conditions, including fractures, osteoporosis, osteomyelitis, tumors, etc. However, all the described methods are based on a comparison of indicators of a healthy and affected limb, which is not applicable for bilateral lesions. With osteoporosis, the mechanical properties of bones in individuals of different age groups are compared, without regard to individual parameters. As the main diagnostic parameter, only the maximum signal amplitude is used, and the influence of soft tissues is not taken into account.

Closest to the proposed method are a method of recording the physiological parameters of the dentition and a method for diagnosing chewing function. The essence of the first method consists in the excitation of mechanical vibrations at one point of the dentition by means of a dosed shock in the middle of the lower jaw, the reception of responses in the form of transformed mechanical vibrations at other points of the system using measuring equipment inserted into the external auditory canal, after which the obtained parameters are compared between themselves and with the reference ones (RF Patent No. 2171788, 1998, A 61 B 8/00, A 61 C 19/04, 1999).

The disadvantages of the method are that the diagnostic conclusion about the presence of pathological changes in the bone tissue is made by the presence of asymmetry of the signal time and its amplitude-frequency characteristic from the right and left half of the study area, which cannot be used, for example, with combined bilateral lesion. In addition, the diagnostic information is not completely extracted due to the fact that the signal is analyzed as a whole; isolated changes in the amplitude and frequency of the signals are not considered in case of violations of the integrity and mineral density of bone tissue. In addition, the disadvantage of this method is that the time of occurrence of a mechanical response is recorded by measuring the time interval from the moment of exposure to the appearance of the response, which is technically difficult to implement and leads to high measurement errors.

The essence of the method for diagnosing chewing function is to excite mechanical vibrations at one point of the dentition by means of a dosed shock in the middle part of the lower jaw, receive responses in the form of transformed mechanical vibrations at other points of the system using measuring equipment, and the mechanical responses to the components are decrypted maximum amplitude, average amplitude, frequency and pulse duration (RF Patent No. 2210309, A 61 V 5/103, 10/00, 2000).

The disadvantage of this method is that the responses are not analyzed by the degree of attenuation of the pulse, while this is one of the informative parameters. In addition, the effect of soft tissues is not evaluated, possibly because in the maxillofacial region they have a slight effect on the nature of the curve, the recording range is limited only to the study of a single mechanical response, and the signals reflected from the sites of integrity and pathological bone changes are not studied. . In connection with the above, the application of these methods is limited to the maxillofacial region and is not very informative with respect to long tubular bones.

The aim of the present invention is to improve the accuracy of diagnosis of biomechanical properties of long tubular bones based on the analysis of additional parameters of mechanical responses.

The goal is realized by the fact that according to the method for recording the biomechanical properties of long tubular bones, mechanical vibrations are excited at a single point in the system by means of a metered impact, followed by the reception, amplification and analysis of mechanical responses in other parts of the system using measuring equipment, after which the mechanical responses are analyzed by travel time, maximum amplitude, frequency and pulse duration, comparing the obtained indicators with each other and with the reference ones, mechanical responses are recorded both from the nearest and from the remote seismic receiver with respect to the point of mechanical impact, the speed of sound propagation along the bone is determined based on the difference in the time of the appearance of the responses, after which an additional analysis of the mechanical responses is performed according to the degree of attenuation, the presence of reflected waves, analysis of the magnitude of the influence of soft tissues is carried out by comparing the received signal with an ideal exponent; in case of fractures, the displacement of fragments is analyzed from below If the maximum amplitude of the mechanical response from the remote geophone is compared with the reference, as well as the time and amplitude-frequency characteristics of the reflected signal from the nearest geophone, the degree of soft tissue interference is calculated as the difference between the amplitudes between the direct signal from the nearest geophone, the reflected signal from the nearest geophone and the signal from a remote seismic receiver, bone mineral density is determined by measuring the frequency and degree of attenuation of mechanical responses, s a decrease in the signal frequency and the degree of attenuation at all seismic receivers compared with the reference one is regarded as osteoporosis, a different degree of attenuation of mechanical responses at the same frequency at the nearest and distant geophones indicates the heterogeneity of bone tissue, in addition, the localization of the pathological focus or fracture site is determined by the time interval between mechanical responses of the direct and reflected signal from the nearest geophone.

Studies on patent and scientific and technical sources of information have shown that the proposed method is not known and does not follow explicitly from the studied prior art, i.e. meets the criteria of "novelty" and "inventive step".

The method is as follows.

Before the examination, the patient undergoes a standard anthropometric study, including measurement of height, body weight, limb length, length of individual segments, the circumference of a healthy and affected limb at different levels. The obtained parameters are entered into a computer database. Then, the meaning of the study is explained to the patient, after which one or a group of wide-band geophones is installed at certain points that are palpated under the skin. For example, for the femur it is a large trochanter, epicondyles, for the lower leg, the condyles of the tibia, part of its diaphysis, head of the fibula, ankles. For the bones of the forearm, the ulnar process of the ulna, the styloid processes, part of the diaphysis of the radius and ulna. For the humerus, the head and epicondyle. In this case, the seismic receivers are located on both sides of the alleged pathological process, for example, the seismic transducer located on the lateral epicondyle of the thigh, while the blow is applied to the medial epicondyle, is conventionally designated as “the closest”, and the seismic receiver located on the greater trochanter of the femur is designated as “ remote". Figure 10 (a is the nearest geophone, in - the remote geophone). Then produce a standard dosed stroke, after which the reception, amplification and analysis of mechanical responses is carried out, followed by their interpretation according to the following parameters:

- response time (t ₁ );

- pulse duration (t ₂ );

- maximum signal amplitude (A _max );

- signal frequency (sin (x));

- degree of attenuation of the signal (e ^-x ).

The process of analyzing the curves is shown in Figs. 4, 5, 6. The signal appearance time is the time between the appearance of the response between the nearest and remote geophones t ₁ in Fig. 4, which, at a known distance, allows one to calculate the propagation velocity of a mechanical impulse over a bone site, for example, the distance between the geophones, equal to 35 cm, the time between responses A and B≈0.00023 sec is fixed, then the speed will be 0.35 m / 0.00023 sec ≈1521.73 m / s. Maximum amplitude - the distance between the maximum and minimum point of the signal. Duration - the time from the appearance to the complete attenuation of the signal. Frequency — response time divided by the number of positive and negative critical inflection points of FIG. 5. FIG. 6 shows an analysis of the degree of signal attenuation by measuring the maximum deviation of all amplitudes from the midline. Fig.7 is a curve showing the degree of attenuation of the mechanical response shown in Fig.6. Subsequently, the obtained parameters from the nearest and distant geophones are compared not only with a healthy limb and with reference ones, which were obtained by examining healthy persons of the corresponding gender, age and constitution, but also among themselves, which is more informative, since there are no two identical people and the anthropometric parameters of the limbs in one person under normal conditions and with pathologies may also not coincide, therefore, in the proposed method, the geophones are located within the same bone.

In the study of bones deprived of soft tissues, the mechanical responses approach the ideal exponent of Fig. 1, therefore, the magnitude of the influence of soft tissues is estimated by comparing the signal with the ideal exponent, constructed on the basis of the data on the maximum amplitude, frequency, and degree of attenuation, by substituting them in formula: f (x) = A _max e ^-x sin (x), Fig.2.

Figure 9 shows the calculation of the curve "C", characterizing the influence of soft tissues on the mechanical response, by subtracting the received signal "B" from the ideal exponent "A" shown in Fig. 8, which, after comparing the obtained parameter with a healthy limb, will make it possible to judge the presence of pathology in the soft tissues, for example, such as edema.

Normally, after a diagnostic shock, the signals from all sensors located at the test points have the form of a decaying exponent shown in Fig. 3. The maximum amplitude of the signal from a remote seismic receiver is at least 95% of the nearest one.

In fractures, the relationship between the size of the contact between the fragments and the decrease in the maximum amplitude of the mechanical response from a distant geophysic in comparison with a healthy limb is determined.

Normally, after an impact, responses from all sensors are recorded only once, since the mechanical impulse passes well through the articular surfaces (Andreev V.N. 1982), however, when examining damaged bones, when the sensors are located on the side of the impact, in addition to the naturally expected first response, after a certain period of time, the appearance of a response reflected from the fracture line, which was taken as an additional diagnostic parameter and is conventionally designated as the reflected signal "C" - 11. In this case, the time of its appearance and the maximum amplitude (Amax2), the frequency response and the degree of deformation in relation to the first signal “A”, which is designated as a direct signal, are analyzed, which makes it possible to judge the contact area of the fragments and the degree of soft tissue interposition. In this case, the effect of soft tissue interposition is calculated by the formula Int.m / mk = A-B-C. “A” is the direct signal of the nearest geophone, “B” is the response from the remote geophone, “C” is the reflected signal from the nearest geophone. For example, when fragments are displaced along the length, the maximum amplitude of the response from the distant geophone is less than 10% of the direct signal from the nearest geophone, while the maximum amplitude of the reflected signal from the nearest geophone reaches 80% of the direct. When the fragments are shifted by 50% in width, the maximum amplitude of the response from the remote geophone is about 30% of the direct signal from the nearest geophone, and the maximum amplitude of the reflected signal from the nearest geophone is approximately 20% of the direct FIG.

Normally, the frequency of the analyzed signal reflects the bone mineral density and depends on gender and age (A.I. Anisimov, V.I. Karptsov, 1993). With osteoporosis, there is a significant decrease in the frequency of signals from all sensors on all limbs, up to 85% of the reference. With systemic osteosclerosis, for example, with marble disease, there is an increase in the frequency of the signal compared with the norm, by an average of 10%, Fig.13.

The degree of signal attenuation reflects the uniformity of the bone tissue and is normally the same in all areas of the bone. With focal changes in the bone tissue in the form of focal osteoporosis, for example with osteomyelitis, there is a decrease in the degree of attenuation on the sensors from the side opposite to the impact, compared with a healthy limb, Fig. 14. With focal osteosclerosis, for example with bone-forming tumors, there is an increase in the degree of signal attenuation on the sensors from the side opposite to the strike, compared with a healthy limb, Fig. 15. Moreover, the localization of the pathological focus or fracture site is determined by the time interval between the mechanical responses of the direct and reflected signal from the nearest geophone - t ₃ in Figs. 11, 12, 14, 15.

The method improves the accuracy of diagnosis of biomechanical properties of long tubular bones by analyzing additional parameters of mechanical responses, which allows differential diagnosis of various pathologies with the ability to accurately determine the topical localization. The method is easily reproducible, non-invasive, does not require preliminary examination, does not bear radiation exposure, has no contraindications, which allows the possibility of use at all stages of medical care both independently and in combination with routine examination methods, as in outpatient practice during initial diagnosis, and in stationary conditions for dynamic observation during treatment.

Literature:

1. RF patent No. 2071274, A 61 B 8/00, 1997.

2. A.S. USSR No. 1680082 A61 B 6/00, 1988.

3. RF patent №2141788, 1998, A 61 B 8/00, A 61 C 19/04, 1999.

4. RF patent No. 2210309, A 61 B 5/103, 10/00; 2000.

5. A.I. Anisimov, V.N. Karptsov Osteometry, functional assessment of bone tissue, S.-P. 1993. Appendix.

Claims (1)

A method for recording the biomechanical properties of bones, including the excitation of mechanical vibrations at a single point in the skeletal system by means of a dosed shock, the subsequent reception of mechanical responses by broadband geophones, amplification of the obtained mechanical responses and analysis of the propagation parameters of a mechanical pulse using measuring equipment, characterized in that the broadband geophones are located on both sides of the pathological focus so that the closest of them is closer to the point mechanically about the impact, register the time difference between the appearance of mechanical responses A and B, respectively, at the nearest and distant geophones, and the parameters for analysis are the speed of propagation of mechanical pulses along the bone, their degree of attenuation and the presence of the reflected response C with the determination of the time of its appearance and maximum amplitude , as well as the frequency response of this signal, while the analysis of the magnitude of the influence of soft tissues is performed by comparing the received signal of the mechanical response with the exponent obtained in the study of bones deprived of soft tissues, the amount of displacement during fractures is determined by reducing the maximum amplitude of the mechanical response from a distant geophone as compared to a reference indicator, which is used as the amplitude of the mechanical response from the nearest geophone or parameters obtained in the study of a healthy limb , the degree of influence of soft tissue interposition is calculated by the difference of the signals of mechanical responses (A-B-C), when determining the mineral of bone tissue values, use the values of the frequency and degree of attenuation of the mechanical responses at the geophones, with a uniform decrease in which osteoporosis is diagnosed compared to the reference indicators, the heterogeneity of the bone tissue is determined by the difference in the frequency and degree of attenuation of the mechanical responses at the nearest and distant geophones, and the localization of the pathological focus or location the fracture is determined by the time interval between the mechanical response A at the nearest geophone and the response reflected from it FROM.

Images