Classifications

• • G—PHYSICS
  • G10—MUSICAL INSTRUMENTS; ACOUSTICS
  • G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
  • G10K15/00—Acoustics not otherwise provided for
  • G10K15/04—Sound-producing devices
  • G10K15/06—Sound-producing devices using electric discharge
• • G—PHYSICS
  • G10—MUSICAL INSTRUMENTS; ACOUSTICS
  • G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
  • G10K11/00—Methods or devices for transmitting, conducting or directing sound in general; Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
  • G10K11/18—Methods or devices for transmitting, conducting or directing sound
  • G10K11/26—Sound-focusing or directing, e.g. scanning
  • G10K11/28—Sound-focusing or directing, e.g. scanning using reflection, e.g. parabolic reflectors

Definitions

• Shock wave generation device provided with an ellipsoidal reflector
• the invention essentially relates to a method of manufacturing a device for generating shock waves for the remote destruction of targets, preferably constituted by concretions, such as renal or biliary lithiasis, said shock waves being little or not sensitive by the patients, thus allowing a treatment without anesthesia, truncated ellipsoidal reflector and apparatus of generation of shock waves comprising application.
• This device comprises a shock wave generator device formed by a truncated ellipsoidal reflector 80 comprising a cavity 81 constituting a reflection chamber for shock waves of the same truncated ellipsoidal shape.
• a shock wave generator device formed by a truncated ellipsoidal reflector 80 comprising a cavity 81 constituting a reflection chamber for shock waves of the same truncated ellipsoidal shape.
• One of the two focal points of the ellipsoid is placed in the chamber opposite the truncated part, this chamber being filled with a liquid for transmitting shock waves 83, for example an oil.
• This chamber is closed by a membrane referenced 37 in FIG. 1.
• the actual shock wave generating device usually comprises two electrodes 12, 13, arranged at least partially inside the chamber 81, these two electrodes being arranged to generate a discharge or electric arc at the focal point 14 located in the Opposite the truncated part.
• Means 10, 11 are also provided for instantly selectively delivering an electrical voltage to the two electrodes 12, 13 thereby causing discharge or electric arc between the electrodes thereby generating shock waves in said liquid contained in the chamber (see Figure 3 and column 7, line 51 to column 9, line 39).
• an electric power generator 10 is provided, in particular a battery 34, selectively supplying a transformer 33 and a capacitor 11 (see column 5, line 64 to column 6, line 26).
• This capacitor can be charged up to a voltage of 15,000 volts and have a capacitance of 1 microfarad, to generate the arc or electric discharge between the electrodes selectively at determined intervals (column 9, lines 7 to 9 and 24 to 27).
• the value of the applied voltage and the size of the capacitor depend on the nature of the intended use, depending on whether the year wishes to destroy tissue or simply stimulate it (column 9, lines 27 to 29).
• This device is used in the medical field, in particular for destroying tissue (see column 3, lines 30 to 64).
• This device can also be used for the exploration or stimulation of various parts of the nervous system (column 3, lines 65 to 74).
• This device can also be used for extra-corporal lithotripsy.
• any anesthesia presents a significant risk for the patient while its implementation requires significant and expensive equipment as well as highly qualified personnel to exercise the necessary surveillance.
• the present invention is therefore based on the results of research which has been carried out with a view to reducing the treatment and hospitalization time of patients in order to improve their comfort by destroying the targets, in particular lithiasis (lithotripsy) without anesthesia.
• a main object of the present invention is to solve the new technical problem consisting in providing a solution allowing treatment of patients using shock waves, without anesthesia.
• the present invention also aims to solve the new technical problem consisting in the supply of a solution making it possible to carry out treatments with shock waves for the destruction of targets constituted by concretions, such as renal and biliary lithiasis. , this treatment still being usually known as "lithotripsy", without anesthesia.
• the present invention also aims to solve the new technical problem consisting in providing a solution making it possible to reduce the duration of treatment with shock waves by requiring only medical supervision of the patients for a few hours. .
• the present invention also aims to solve the new technical problem consisting in the supply of a solution making it possible to carry out the treatments with shock waves, without anesthesia, while maintaining the pressure value.
• peak shock waves at values equivalent to the peak pressure values usually used or necessary to obtain the disintegration of targets, and in particular concretions, such as in particular renal and biliary lithiasis, thereby ensuring equivalent destruction efficiency.
• the present invention provides a method of manufacturing a device generating shock waves for the remote destruction of targets, for example constituted by concretions, such as renal, biliary lithiasis, said waves shock being little or not sensitive by patients, allowing treatment without anesthesia, characterized in that it consists in manufacturing a device generating shock waves emitting shock waves having an average energy density value less than approximately 0.23 joule / cm 2 at least in a plane perpendicular to the axis of symmetry, or focal axis, of the emitting device, which is intended to correspond substantially to the position of the patient's skin to be subjected to shock waves.
• the average energy density of the shock waves is between 0.01 joule / cm 2 and 0.23 joule / cm 2 and even better between 0.02 joule / cm 2 and 0.15 joule / cm
• the capacity of this is reduced.
• capacitor at a Capacitance value less than or equal to 500 nanofarads.
• this value of capacitance of the capacitor is between 50 nanofarads and 500 nanofarads, even better, between 60 and 200 nanofarads.
• an ellipsoidal reflector for generating shock waves is produced having a ratio of small diameter (b) to large diameter (a) (b) / (a)> 0.60, even better between 0.60 and 0.85.
• this ratio (b) / (a) is approximately equal to 0.64, while, according to another particular embodiment, this ratio (b) / (a) is approximately equal to 0.75.
• the reduction of this capacitance is carried out in combination with the values of the aforementioned ratio (b) / (a) of the ellipsoidal reflector with the aid of which are reflected. shock waves generated by the shock wave generating device.
• This combination indeed makes it possible to deliver shock opals of reduced energy density, little or not sensitive by the patient.
• the invention also relates to an apparatus for generating shock waves equipped with a device for generating shock waves produced by the aforementioned method, that is to say with a capacitor having The capacity value previously defined, preferably equipped with a truncated ellipsoidal reflector having a ratio (b) / (a) as defined above.
• the invention also relates to a truncated ellipsoidal reflector per se intended to generate shock waves which are little or not sensitive by the patients, characterized in that it has a ratio (b) / ( a) equal to approximately 0.64 or approximately 0.75.
• a completely surprising or unexpected result of the invention lies in the fact that this reduction or elimination of the sensitivity of the shock waves is obtained while maintaining the peak pressure values of the shock waves at values equivalent to the previously used peak pressure values which are necessary for the decay of concretions, such as in particular renal or biliary lithiasis.
• FIG. 1 shows atically an ellipsoidal reflector forming part of an apparatus for generating shock waves with the essential part of the electrical power supply connection of the electrodes including in particular a capacitor;
• FIG. 2 shows schematically in axial section a truncated ellipsoidal reflector according to the present invention.
• an apparatus for generating shock waves in a liquid 2, for example water, for the remote destruction of targets, such as concretions, for example lithiases renal, biliary, comprises a device 4 generating shock waves by electrical discharge between at least two electrodes 6, 8 arranged at least in part in a chamber 10 here shown in ellipsoidal shape being defined by a truncated ellipsoidal reflector 12 filled with liquid 2.
• the shock wave generator device of truncated ellipsoidal shape
• the electrodes 6, 8 can be mounted on a device for advancing 'electrodes as described in the prior application FR-A-2 598 074 which is here incorporated by reference and which is therefore not described in more detail.
• the electrodes 6, 8 are advantageously supplied intermittently from a source of electric current 22 by a connector 14 for supplying electric current.
• This connector 14 for supplying electrical current to the electrodes 6, 8 comprises in particular a capacitor 18 capable of storing a voltage of 0 to 20,000 volts, interposed for example on the conductor 20 for supplying electrical current to the electrode 8 from the electric current source 22, combined with a high voltage transformer 24, and leading to a sliding contact or else to a contact nut, ensuring permanent electric contact with the electrode 8 or with an element electrode holder as described in Applicants' prior applications.
• the power supply connector 14 advantageously comprises an intermediate device 28 for closing the electrical circuit between the electrodes 6, 8 intermittently, preferably Spark Gap type, interposed in the example shown on the other supply conductor 30 of the other electrode 6.
• one of these conductors 20 or 30 is connected to earth T as symbolized in FIG. 1.
• This intermediate device 28 is advantageously constituted by a housing 32 in which two intermediate electrodes 34, 36 are arranged at a distance, this distance being sufficient to interrupt the electric circuit.
• This electric circuit is closed by the generation of spark plugs from a spark generating element 38, for example a spark plug, of the automotive spark plug type or the like.
• a spark generating element 38 for example a spark plug, of the automotive spark plug type or the like.
• a device is produced which generates shock waves which are little or not sensitive by the patients, thus allowing treatment without anesthesia.
• the manufacturing process consists in reducing the average energy density of shock waves at least in the region of penetration of said waves in the body at the cutaneous level to an average energy density value of shock waves which is little or no sensitive by patients.
• this value of energy density it is preferred to reduce this value of energy density to a value between 0.01 and 0.23 joule / cm. even better between 0.02 and 0.15, particular values being approximately equal to 0.04-0.05.
• FIG. 2 which represents in enlarged axial section a truncated ellipsoidal reflector 12 according to the invention, with the electrodes 6, 8 removed, the hearth F1 has been represented or the shock waves are generated by means of a discharge electric between the electrodes 6, 8 and the second focal point F2 situated outside the truncated ellipsoidal reflector 12 and which will then be brought into coincidence with the target to be destroyed, in particular a concretion such as a renal or biliary lithiasis .
• a concretion such as a renal or biliary lithiasis
• the first zone is the lower part defined by F1 DAC said lower zone.
• the other zone is the upper part defined by F1 DFEC, called the upper zone.
• FIG. 1 shows the point G which symbolically corresponds to the position of the patient's skin to be subjected to treatment with shock waves.
• This point G makes it possible to define a plane perpendicular to the focal axis which can be defined by the Letters J, I, G, H, K.
• the first focusing area is defined by F2 DAC and includes the areas reflected on the DAC wall, ie 50% of reflected energy.
• the second zone is peripheral to the first zone, is defined by (F2 FD) (F2 EC), therefore constitutes a zone of revolution and includes The waves reflected on the wall FD or EC, or 30% of the energy reflected.
• intersection of the first zone with the plane perpendicular to the focal axis passing through the point G is a circular section S1.
• intersection of the second zone with the surface in G is an annular section of surface S2.
• the energy density appearing mainly on the surface S1 as well as on the surface S2 is therefore reduced so that this energy density is less than a sensitivity threshold of the patient, at the skin level, symbolized here by the point G and by the plane perpendicular to the focal plane passing through the point G, defined here by the points J, I, G, H, K.
• the average energy density of the shock waves is reduced below the average energy density value causing sensitivity for the patients by providing that the discharge capacitor 18 has a Capacitance less than or equal to 500 nanofarads.
• the capacitance of the capacity 18 is between 50 nanofarads and 500 nanofarads, an even more preferred range being between approximately 60 nanofarads and 200 nanofarads.
• this reduction in energy density is favored by manufacturing a truncated ellipsoidal reflector 12 whose ratio of the small diameter (b) to the large diameter (a) (b) / (a)> 0.60.
• this ratio (b) / (a) is between 0.60 and 0.85.
• this ratio (b) / (a) is approximately equal to 0.64. According to another particularly advantageous embodiment, this ratio (b) / (a) is approximately equal to 0.75.
• Capacitance values are used in combination with the ellipsoidal reflectors designed according to the invention, that is to say having a ratio (b) / (a) > 0.60, which makes it possible to obtain a considerable increase in the results and a certain and reproducible obtaining of shock waves of reduced energy density according to the invention.
• Table I reports the reduction in the average energy density as a function of the shape of the ellipsoid used and the value of the capacitance of the discharge capacitor.
• an ellipsoidal reflector according to the present invention having a ratio (b) / (a)> 0.60, that is to say first here 0.64 and a capacitance less than or equal to 0.5 microfarad . here respectively 0.5 and 0.2 microfarad, the average energy density obtained in joule / cm 2 is respectively 0.13 and 0.05.
• the average pressure in megaPascal is 100, which is equivalent to 1000 bars, which is too high a pressure ”
• the Capacitance is reduced to a value of 0.2 microfarad, which gives rise to no surface sensitivity and the treatment can therefore be carried out without anesthesia , but possibly for the comfort of the patient with a slight analgesia.
• the pressure value is measured with a reference pressure sensor PCB119A02 which has a natural frequency of 500 kilohertz.
• This pressure sensor filters the rise times of the shock wave and delivers a constant value of 500 nanoseconds. It can likewise filter the decay of the wave at a value of 500 nanoseconds.
• the measured energy density is an average energy density which is obtained by averaging the energy densities obtained as a function of the distances. This energy density is obtained from the measured peak pressure (Pc).
• Table III the values are given.
• the reflected energy (RE) is indicated as a percentage
• the angle is the angle DF2A shown in Figure 2
• ⁇ is the angle FF2A, Figure 2.
• the angle / ⁇ gives the solid angle > o (/> defined by FF2E by revolution around the axis F1F2.
• the external solid angle of reflection defined by the solid angle of revolution FF2BCF2B-2 external equal to 2 minus ⁇ j , as well as the respectively internal and external energy coefficients defined in Table III.
• a further reduction of approximately 50% is obtained by choosing the ellipsoidal reflector according to the invention having a ratio (b) / (a) equal to 0.75, while maintaining an external energy coefficient practically similar to that of the ellipsoidal reflector according to the invention having a ratio (b) / (a) equal to 0.64.
• Another completely unexpected advantage of the invention resides in the fact that by modifying the shape of the ellipsoidal reflector so that it has a ratio (b) / (a) / 0.60, a finer focal spot is obtained. with a better energy concentration at the external focal point F2, which makes it possible to further reduce the risk of damage to the tissues surrounding the target to be destroyed, whether it is a tissue or a concretion, by better accuracy of shots.
• the frequency spectrum is composed of high frequency components due to the short rise time of the wave and low frequency components due to the return to equilibrium of the wave with a very large time constant in front of the wave rise time.
• the rise times with PVDF sensors are around 200ns.
• the time constants are of the order of 1 LIS.
• the low frequency components are very energetic and seem strongly perceptible by patients when the time constant of the wave becomes greater than 1.5 ⁇ us.
• the shock waves have a high frequency greater than 300 ki Lohertz while the shock waves, according to the prior art, having a low frequency and a high energy density, cause skin bonds. , which is clear from Table I below.
• the invention includes all the means constituting technical equivalents of the means described as well as their various combinations.
• shock waves which are little or not sensitive at the cutaneous level for the patient we mean waves of shock which, although they can be felt by the patient, are tolerable and do not require anesthesia, simply analgesia for the duration of the treatment to improve the comfort of the patient.

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• Physics & Mathematics (AREA)
• Engineering & Computer Science (AREA)
• Acoustics & Sound (AREA)
• Multimedia (AREA)
• Electrotherapy Devices (AREA)
• Surgical Instruments (AREA)

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• 1987
  • 1987-11-16 FR FR8715799A patent/FR2623080A1/fr not_active Withdrawn
• 1988
  • 1988-11-15 EP EP88910060A patent/EP0389531A1/de not_active Withdrawn
  • 1988-11-15 WO PCT/FR1988/000560 patent/WO1989005026A1/fr not_active Application Discontinuation
  • 1988-11-15 JP JP63509458A patent/JPH03500851A/ja active Pending
  • 1988-11-15 US US07/460,119 patent/US5233980A/en not_active Expired - Lifetime

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