Classifications

• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B8/00—Diagnosis using ultrasonic, sonic or infrasonic waves
  • A61B8/08—Detecting organic movements or changes, e.g. tumours, cysts, swellings
  • A61B8/0875—Detecting organic movements or changes, e.g. tumours, cysts, swellings for diagnosis of bone

Definitions

• the present invention essentially relates to the use of ultrasound for the detection and localization of a bone area, as well as a method and a device for detecting and localizing a bone area by ultrasound. More particularly, the invention uses ultrasound to detect and locate a fracture and, according to a preferred application, this fracture localization and detection is used in the context of shock wave fracture therapy.
• Document WO88 / 09190 already discloses a method and a device for the medical treatment of the pathological condition of the bones using shock waves.
• the apparatus used consists in practice of a lithotriptor comprising a device generating shock waves using a truncated ellipsoidal reflector, the shock waves being generated at the first internal focus of the truncated ellipsoid and focused at the second external focus where is located the target to be treated. Detection and localization is done using an X-ray generator arranged extremely precisely relative to the generator.
• Other similar documents are constituted by EP-A-0324 163 and EP-A-0 324 711 by describing the use of lithotriptor for the treatment of fracture in particular by induction of bone growth.
• the methods and devices described in the prior art relating to the pathological treatment of bones do not really describe a method for automatic detection and localization of the bone area to be treated.
• the technique used is that of X-rays which has the disadvantage of subjecting the patient to doses of X-ray irradiation which are undesirable and which can lead to side effects.
• the irradiation dose may be important since several detection and localization tests are required during shock wave therapy.
• the object of the present invention is therefore to solve the new technical problem consisting in providing a solution which makes it possible to carry out the detection and localization of bone area in complete safety, that is to say without the use of rays. X or similar harmful radiation.
• the present invention also aims to solve the new technical problem stated above by the implementation of a solution which makes it possible to carry out an automatic detection and localization of the bone area to be treated, which advantageously allows subsequently to apply this method and this device in an extremely simple manner in shock wave therapy.
• the present invention solves these new technical problems for the first time, in a particularly simple manner, usable on an industrial scale.
• the present invention relates to the use of ultrasound for the detection and localization of a determined bone area, in particular a fracture, or a bone affection such as a pseudo-arthritis.
• the present invention also provides a method for detecting and locating a determined bone area, in particular a fracture or a bone condition such as pseudo-arthritis, characterized in that at least one ultrasonic transducer element which is used to detect and locate said determined bone area.
• this is characterized in that it comprises: a ) the provision of at least one ultrasonic transducer element, chosen from a range of ultrasonic frequencies which makes it possible to have sufficient resolution of the detected echoes to determine the presence of said bone area; b) the transducer element and / or a bone support element including said bone area is relatively displaced, so that the transducer element passes over said bone area; c) transmitting ultrasonic signals to said transducer element during this movement; d) the echoes reflected by the transmitted signals are detected and compared with a reference echo until a modification of the echo is detected, for example a reduction in the level of the echo or a delay in its appearance , or the appearance of a secondary echo, constituting a sign of the presence of said determined bone area; and e) the position of said bone area is recorded.
• the method according to the invention is characterized in that it comprises: a) the provision of at least one ultrasonic transducer element, preferably mounted movable in space in the directions X, Y, Z, this transducer element being chosen from a range of ultrasonic frequencies which allows sufficient resolution of the echoes detected to determine the presence of said bone area; b) said transducer element and / or a bone support element including said bone area is relatively displaced in a direction substantially perpendicular to the longitudinal direction of said bone to be observed; c) transmitting ultrasonic signals to said transducer element during this displacement and analyzing the level and / or the time of appearance of the echoes obtained; d) the maximum amplitude and / or the minimum time for the echo to appear on the bone area of interest is sought in this analysis in order to determine a generator of the bone; e) then moving said transducer element or said bone support element, perpendicular to its initial direction to follow said bone generator thus determined while continuing to transmit ultra
• the ultrasonic transducer element is moved step by step.
• the distance between the transducer element and the surface of the bone is determined from the time of appearance of the echo with respect to the transmission signal.
• the coordinates in space of said bone area are recorded and the coordinates are recorded as the coordinates of a target point which must be placed in coincidence with the focal point of a generator. shock waves.
• the coordinates to be recorded are those of the point on the surface closest to the transducer element.
• ultrasonic transducer elements are used, in particular that one divides into two groups of transducer elements arranged at a known predetermined angle and all of the transducer elements are moved until the values for the delay of appearance of the echo on the identical bone are obtained, which makes it possible to place the bone in the median plane defined by the two groups of transducer elements.
• an ultrasonic transducer element is used, monocrystal or with sectoral scanning, or of the "strip" type.
• an ultrasonic transducer element is used emitting ultrasonic waves at a frequency between 3 MHz and 10 MHz, ideally between 5 and 7 MHz.
• the present invention also provides an apparatus for detecting and locating a determined bone area, in particular a fracture or a bone condition such as a pseudo-arthritis, characterized in that it comprises: a) at least one ultrasonic transducer element chosen from an ultrasonic frequency range which makes it possible to have sufficient resolution of the echoes detected to determine the presence of said determined bone area; b) means for moving said transducer element and / or a bone support element including said bone area, so that the transducer element passes over said bone area; c) means making ultrasonic signals emit to said transducer element during this movement as well as means for detecting echoes emitted by reflection; d) means for processing the detected signals capable of comparing them with detected signals serving as a reference, and determining a modification of the echo, for example a reduction in the level of the echo or a delay in its appearance, or the appearance of a secondary echo, constituting a sign of the presence of said bone area; and e) means for calculating and recording
• the invention provides an apparatus for detecting and locating a determined bone area, in particular a fracture or a bone condition, such as a pseudo-arthritis, characterized in that it comprises: a) at least one ultrasonic transducer element chosen from an ultrasonic frequency range which makes it possible to have sufficient resolution of the echoes detected to determine the presence of said determined bone area; b) means for moving said transducer element and / or a bone support element including said bone zone, in space in the directions X, Y, Z; above said bone area; c) means for transmitting signals to the transducer element during this movement as well as means for detecting echoes emitted by reflection; d) means for processing the detected signals capable of analyzing them to determine the level and / or the time of appearance to define a bone generator which will be followed to locate said bone area itself; e) means for controlling the means of displacement of the transducer element and / or of said bone support element, in space in the directions X, Y, Z
• control means comprise a computer device controlling the speed and the direction of movement of the ultrasonic transducer element and / or of the bone support element, preferably in function of initially programmed data, as well as echo data collected by the transducer element.
• the computing device calculates the distance between the position of the transducer element in space and the surface of the bone from the time of appearance of the echo and constitutes the abovementioned means of calculation and recording of the position of the bone area.
• the coordinates recorded are those of the point on the surface closest to the transducer element.
• the device comprises several ultrasonic transducer elements, in particular distributed in at least two groups of transducer elements arranged at a predetermined angle known, and operating simultaneously in transmission-reception, which makes it possible to position the bone in a median plane defined by the two groups of transducer elements.
• the coordinates in space of a point on the surface of said bone area closest to the transducer element are transmitted by the computer device as coordinates of a target point which must coincide with the focal point of a shock wave generator; preferably, the computing device controls a displacement of the shock wave generator in space so that its focal point coincides with this target point.
• the characteristics of the ultrasonic transducer element are as described above in the context of the method.
• ultrasonic transducer with sector scanning or of the "strip" type is advantageous in that it makes it possible to suppress the displacement of the transducer elements in the phase of detection of the desired bone area or to possibly build an ultrasound image without displacement of the transducer.
• the detection and localization apparatus comprises several transducer elements.
• these transducer elements are distributed into at least two groups of transducer elements arranged between them at a known angle and operating simultaneously in transmission-reception, which makes it possible to position the bone in a median plane defined by Both groups of transducer elements.
• the set of transducer elements is mounted on a mobile system whose movements in space are coded with respect to a fixed reference.
• This fixed reference may be constituted by an element integral with the device supporting the patient, easily detectable by ultrasound, for example, a particular geometric shape.
• the transducer elements are in a fixed position and to place the bone, therefore the patient, on a mobile device. And it is also possible, thanks to the use of transducer elements with focusing line, to provide the transducer elements and the patient support means mounted on systems which remain fixed although these do not offer the maximum of Freedom for the practitioner. Thanks to the use of ultrasonic transducer elements, therefore of ultrasound means, the invention makes it possible to overcome the constraints linked to radiation, in particular X-rays, to have information quickly exploitable by electronic means and simple computer systems which thus make it possible to control in real time the apparatus for generating shock waves without resorting to complex image processing, as well as automating the therapy process and considerably reducing the duration of the treatment.
• the present invention also relates, according to a fourth aspect, an apparatus for generating shock waves focused at a focal point to be brought into coincidence with a target point, comprising control means controlling a movement of the wave generator. of shock in space so that its focal point coincides with the target point, characterized in that the control means determine the coordinates of the target point as being those of a point in a determined bone area to be treated, said coordinates of the point of said bone area being obtained by the use of at least one ultrasonic transducer element, in particular by the implementation of the method or of the detection and localization apparatus previously described.
• the shock wave generating apparatus is characterized in that it comprises a shock wave generator chosen from the group consisting of truncated ellipsoidal reflector filled with a liquid such as the water, closed or not by a membrane, a focused hemispherical dome element, focused magnetostrictive elements.
• the shock wave generation apparatus is characterized in that the above-mentioned transducer element is integrated or mechanically linked to the generator of focused shock waves, so that the movements are simultaneous.
• FIG. 1 is a schematic view of a device for detecting and locating a specific bone area, in particular a bone fracture or condition, such as a pseudo-arthritis, applied, in a mode of preferred embodiment, in an apparatus for generating shock waves;
• FIG. 2 shows an alternative embodiment of the detection device constituted by a single crystal ultrasonic transducer element according to the invention
• - Figure 3 shows an alternative embodiment of the detection device consisting of an ultrasonic transducer element with sectoral scanning
• - Figure 3a shows an alternative embodiment of the detection device constituted by a transducer of the "strip" type
• - Figure 4 shows an alternative embodiment of the detection device consisting of transducer elements distributed in at least two groups of transducer elements arranged at a predetermined angle relative to the vertical;
• - Figure 5 shows in 5a an example of displacement of a transducer element along the Y axis relative to a bone,
• Figure 5b represents the echo level obtained as a function of the displacement in the Y direction and
• Figure 5C represents the delay of appearance of the echo as a function of the displacement in the direction Y;
• FIG. 6 represents the ultrasonic emission, interface echo, bone reflection and parasitic reflection curves, as well as the observation window including the maximum echo level
• FIG. 7 shows in 7a a stepwise movement of the ultrasonic element in X and Y and in 7b the corresponding reflected sound echo;
• FIG. 8 shows schematically the acoustic field of an ultrasonic transducer element with the focusing area and in the vicinity of the determined bone area, for example here a fracture;
• FIG. 9 represents a preferred embodiment according to which the transducer element is integrated or mechanically linked to the generator of focused shock waves, so that the displacements are simultaneous.
• a device for detecting and locating a bone area 4 on a bone 6 of a patient is represented by the general reference number 10.
• This device is characterized in that that it comprises at least one ultrasonic transducer element 12.
• This ultrasonic transducer element 12 is chosen from a range of ultrasonic frequencies which makes it possible to have sufficient resolution of the echoes detected to determine the presence of the bone area 4.
• the apparatus is characterized in that it comprises means 14 for moving the transducer element 12 in space in the directions X, Y, Z.
• These displacement means comprise means coding in Cartesian coordinates X, Y, Z and / or in polar coordinates R, theta, phi.
• This device also includes means 16 for transmitting signals to the transducer element 12 as well as means for detecting echoes emitted by reflection, integrated in an electronic device well known to those skilled in the art.
• the apparatus according to the invention also or advantageously comprises means 18 for processing the detected signals, capable of comparing these with detected signals serving as a reference, and comprising means for determining the distance separating the transducer element from the surface of the bone from the time of appearance of the echo reflected by the bone, when the processing means note a variation in the level of echo, for example a reduction or a delay in its appearance, or else L appearance of a secondary echo, constituting a sign of the presence of the bone area 4.
• the apparatus according to the invention also advantageously comprises means 20 for controlling the means of displacement 14 of the transducer element 12 in the space according to directions X, Y, Z, including in particular the data transmitted by the processing means 18, for example by the presence of a computer device.
• the transducer element 12 is integrated or mechanically linked to an apparatus 30 for generating shock waves focused at a focal point F, in particular to the focused generating device 32, for example a truncated ellipsoid 32 emitting the waves of shock in an internal focal point F1 which are focused on the external focal point F, which is well known to those skilled in the art, as shown in FIG. 9.
• the means 20 for controlling the means of movement 14 of the transducer element 12, for example comprising a computer device, also control the movement in space in the directions X, Y, Z of the shock wave generator 32 which also includes means for coding in Cartesian coordinates X, Y, Z and / or polar coordinates R, theta, phi.
• the control means 20, comprising a data processing device are common to the detection and localization apparatus and to the shock wave generation apparatus, which constitutes an important advantage of the invention.
• the coding of the position coordinates in space of the ultrasonic transducer element 12 and of the shock wave generator 32 are carried out with respect to a fixed reference.
• This fixed mark is for example constituted by an element integral with the device supporting the patient, easily detectable by ultrasound, for example a particular geometric shape.
• the transducer element 12 can be a single crystal (focal point 24) as shown in FIG. 2, or with sector scanning (focal line 26) as shown in FIG. 3, or of the "strip" type. (focal line 26 bis) as shown in Figure 3a.
• FIG. 5a shows the displacement of an ultrasonic transducer element 12 along the axis Y on the surface of the skin 8 of a member of a patient containing a bone 6 to be observed.
• FIG. 5b shows on the ordinate the level N of reflected echo as a function of the displacement along the axis Y, the closest position S of the bone corresponding to the maximum reflected echo.
• FIG. 5c represents the delay of appearance of the echo as a function of the displacement along the axis Y and it is observed that the nearest point S corresponds to a shortest delay of appearance.
• FIG. 6 represents over time the sound level of the emission signal and of the interface echoes, of reflection on the bone and parasites, symbolizing the observation window which is the space of time observed to detect the reflection echo on the bone 4.
• FIG. 7 represents the step-by-step displacement of the ultrasonic element 12 by the displacement means 14 controlled by the control means 20 by a distance Dx along the axis of the abscissae X and by a distance DY on the axis ordinates Y (figure 7a).
• FIG. 7b presents the level or the delay of the sound echo reflected during the preceding displacements dx and dy.
• a partial enlarged view at the desired bone area 4 for example constituted by a fracture 5 defining a fracture of the bone 6 with a width l and a depth for example equal to h, thus that the focusing zone, for example 24 of the transducer element 12. It is observed that it is advantageous that the focusing zone 24 provides sufficient resolution of the fracture 5 and is here for example of a dimension less than the Width l the fracture caused by the fracture 5.
• this method is according to a preferred embodiment variant, carried out as follows:
• the transducer element 12 is automatically moved, by means of its support means 14 in a direction substantially perpendicular to the longitudinal direction of a bone 6 to be observed.
• the position in space of the transducer element 12, that is to say in practice of the support means 14 are transmitted to the means 16 and to the processing means 18.
• the means 16 cause signals to be emitted.
• At least two groups of transducer elements are used which form a known angle between them (2oc). These two groups of transducer elements 12a, 12b operate simultaneously in transmission-reception. The delay for the appearance of the echo on the bone during a movement similar to that described above is determined for a single group of transducer elements for each group. When the two appearance delays have an identical value, the bone is then located in the median plane defined by the two groups of transducer elements 12a, 12b.
• This variant of the method according to the invention ensures both the detection of the bone 6 and its positioning relative to the detection device defined by the transducer elements 12 mounted on the support means 14.
• the means 16 and the means 18 ensure the electronic processing of the electrical signals transmitted by the transducer elements 12 to result in the determination of the maximum levels and the time periods for the appearance of the maximum reflected echoes and transmit this information to the control means 20 which usually include a computer device which in turn controls the displacement in space of the support means 14 and therefore of the transducer elements 12.
• the transducer element 12 After determining the generator of the bone in the Longitudinal direction of the bone, the transducer element 12 is displaced by displacement of its support means 14 controlled by the control means 20 according to this generator, for example parallel or coinciding with the axis X.
• the transducer element 12 After having displaced the transducer element 12 in the direction Y, perpendicular to the longitudinal axis of the bone in the direction X, the transducer element 12 is now moved parallel to the longitudinal direction of the bone, in the X direction.
• the transducer element 12 leaves the generator and the level of the echo decreases.
• the generator of the bone is then found by searching in an identical manner to the previous step, The maximum of the signal for a perpendicular movement in the direction Y.
• the monitoring of the generator of the bone is then ensured by searching for each displacement along the X (D) axis, the maximum level of the echo when moving in the direction Y (D) y
• the tracking of the bone generator is obtained by searching for each step D, the displacement D which makes it possible to obtain on each group of elements transducers 12a, 12b The same delay in the appearance of the echo on the bone. In these conditions.
• the bone is refocused in the median plane defined by the two groups of transducer elements 12a, 12b. It is observed that the same means 16, 18 and 20 make it possible to carry out the phase of detection and monitoring of the generator of the bone. When monitoring the bone generator, we will detect and locate the bone area sought.
• the detection and localization of the desired bone area and the detection of the desired area is based on the discontinuity of the bone medium at the level of the area of interest 4, which causes a transient disturbance of the ultrasound signal.
• this disturbance results in a delay in appearance "t" linked to the dimension "h” of the bone discontinuity, resulting for example from a fracture 5 as well as 'to the decrease in level "L” linked to the various reflections and transmissions in the cortex of bone 6, or to the appearance of secondary echo.
• Optimizing the axial and azimuthal resolution characteristics leads to the choice of the most suitable transducers.
• the means 16, 18 and 20 make it possible to detect the discontinuities of the electrical signals.
• the invention naturally makes it possible to analyze the signal of a single transducer 12 or of several transducer elements in order to search for bone discontinuities.
• This bone discontinuity can also be constituted by osteoarthritis or pseudo-arthritis.
• the desired bone area is detected, it will be located as follows.
• the bone discontinuity being detected as described above, the positioning information of the transducer element 12, and the delay in the appearance of the echo on the bone obtained by the processing means 18 are transmitted to the control means 20 including a computer device where they are stored in memory. These data are then processed by computer to deduce the position in space of the desired bone area.
• the control means 20 control the displacement of the shock wave generator 32 so that its target focus F is adequately disposed with respect to the bone area 4 to carry out its treatment with shock waves.
• This shock wave treatment can be carried out as described in the aforementioned documents.
• the apparatus methods according to the invention can be implemented on any type of shock wave generator because it is completely independent of the technology chosen for the generation of shock waves.
• control means 20 comprise a computer device managing all the systems used and in particular also controlling the shock wave generator in its positioning and in the triggering. of the waves themselves, which makes it possible to automate the therapy process and considerably reduce the duration of treatment. Thanks to the method and to the apparatus according to the invention, it is possible to carry out the treatment of pseudo-arthritis without resorting to open surgery, to accelerate the consolidation of fractures of the limbs or bones without resorting to open surgery. It is also possible to loosen prostheses or remove prosthetic cements.
• the bone area sought may be either a fracture, or areas of osteoarthritis or pseudo-arthritis, or a prosthesis, or a prosthetic cement, which increases the universality of the method and of the apparatus according to the invention.
• ultrasonic transducer elements emitting in a frequency range between 3 and 10 MHz, ideally between 5 and 7 MHz.
• the invention includes all the technical means constituting technical equivalents of the means described as well as their various combinations.
• the support means 14 of the transducer elements 12 can be integral with the shock wave generator and thus constitute only one mobile assembly.
• the invention is applicable to any device for generating shock waves. It may in particular be a shock wave generator chosen from the group consisting of truncated ellipsoidal reflector filled with a liquid such as water, closed or not by a membrane, an element in a focused hemispherical dome, focused magnetostrictive elements.

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• 1990
  • 1990-03-27 FR FR9003916A patent/FR2660186A1/fr not_active Withdrawn
• 1991
  • 1991-03-21 WO PCT/FR1991/000228 patent/WO1991014400A1/fr not_active Application Discontinuation
  • 1991-03-21 EP EP91907251A patent/EP0568529A1/de not_active Ceased
  • 1991-03-25 IL IL97662A patent/IL97662A0/xx unknown
  • 1991-03-26 US US07/675,210 patent/US5235981A/en not_active Expired - Fee Related

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