Abstract:
The invention relates to an apparatus for high energetic ultrasound tissue shrinkage in a target area inside a living body from an outside surface or a body cavity of the living body. The apparatus comprises an ultrasound generator, a device to the applied against the skin or mucous membrane at the site of treatment, and a transducer connected with the ultrasound generator to emit generated therapeutic ultrasound energy through said device. Means are provided for cooling a contact surface of the device to be engaged with the skin or mucous membrane, and the device is made as an exchangeable product forming a heat exchange element between the device and the tissue.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The invention relates to method and apparatus for high energetic ultrasonic tissue in a target area inside a living body from the outside or a cavity of the living body.  
           [0003]    More particularly the invention relates to method and apparatus for eliminating or substantially reducing snoring and opening up or enlarging narrow airways and for tissue shrinkage in the head and neck region by non-invasive ultrasonic medical treatment.  
           [0004]    2. Description of the Prior Art  
           [0005]    Snoring is the result of several contributing factors such as narrow airways, enlarged tongue, deviated nasal septum, and enlarged turbinates or nasal polyps. Another reason can be a decrease in upper airway muscle tone, occurring during sleep. These conditions produce an increased airway resistance and a negative intraluminal pressure during inspiration resulting in traction and vibration of tissues in the upper airway. Most prone to vibrate is the soft tissue, including the tonsils, soft palate and uvula but also the tongue base. Snoring is associated with serious health risks. It may result in significant sleep disruption or fragmentation that may lead to daytime fatigue and sleepiness resulting in safety risks. It has been shown that habitual snoring is related to hypertension, hearts disease and stroke. During pregnancy snoring is a significant health risk both for the woman and for the child. Another serious condition associated with snoring is obstructive sleep apnea which leads to increased mortality.  
           [0006]    Several methods to treat snoring have been developed. Conservative, mechanical and pharmacological non-surgical methods such as weight reduction, alteration of sleep position, smoking cessation, and elimination of sedatives or alcohol intake during evening hours. Dental prosthetic and tongue retaining apparatuses are used with positive effect in some selective patients. Medical treatment of nasal allergies and endocrine problems can be helpful for certain patients.  
           [0007]    However, when snoring becomes loud, habitual and disruptive to others, the patients ought to be considered for a more advanced intervention. Uvulopalathopharyngoplasty (UPPP) is a conventional surgical method demanding general anesthesia which can be difficult in this group of patients wish narrow airways. The method of choice today is laser-assisted uvulopalatoplasty (LAUP). In local anesthesia the soft palate (velum palatinum) and the uvula are vaporized and ablated using a CO 2 -laser equipment. This type of operation can be performed in small offices as a single operation or sometimes have to be done in as much as 5 different stages. One drawback of this method is that tissues are actually cut away during the operation and that the risk for infection therefore cannot be excluded. Accordingly, the patients are treated with antibiotics postoperatively. Another major drawback is the heavy pain during several weeks with need for systematic pain medication and topical anesthetics. The patients are often unable to work for about two weeks after the operation.  
           [0008]    Another invasive method to treat snoring is to insert RF-electrodes as needles in the tissue to be treated (e.g. tongue, uvula, soft palate, turbinates). Through the needles electromagnetic energy is delivered which will diminish the tissue by heating.  
           [0009]    JP-A-05076538 describes an ultrasonic therapeutic apparatus for treating deceased tissue by heating with ultrasonic energy so as to destroy the deceased tissue, wherein means are provided for detecting the position of the target area and for focusing the ultrasonic energy on that area. A transducer for emitting ultrasound energy from an ultrasound generator is displaceably mounted in a water filled housing partly defined by a membrane which is engaged with the skin or mucous membrane at the treatment site. The position of the transducer is adjusted in relation to the housing and thus in relation to the membrane in order to accurately focus the emitted ultrasound energy on the target area to be treated so that an accurate treatment of the target area will be achieved while avoiding detrimental influence on surrounding tissue as well as skin and mucous membrane.  
           [0010]    U.S. Pat. No. 4,936,303 discloses a similar apparatus having a housing with a membrane which is engaged with the skin at the treatment site. In this case fluid is circulated through the interior of the housing over the inside surface of the membrane said fluid being temperature controlled to provide a constant surface temperature at the treatment site.  
         BRIEF SUMMARY OF THE INVENTION  
         [0011]    The primary object of the present invention is to provide method and apparatus for high energetic ultrasonic tissue shrinkage in a target area inside a living body from an outside surface or a cavity of the living body in order to achieve a fibrous tissue development and thereby shrinkage of the tissue under mucous membrane or skin in the head and neck region without destroying or adversely affecting tissue surrounding the target area.  
           [0012]    Another object of the invention is to provide an apparatus of the kind referred to which produces and controls cooling of the skin or mucous membrane at the treatment site.  
           [0013]    A further object of the invention is to provide an apparatus of the kind referred to which is particularly well suited for treatment of the uvula and the soft palate adjacent the uvula at each side thereof in order to eliminate or substantially reduce snoring. By exposure of the uvula and the soft palate to high energetic ultrasound fibrous tissue development will be achieved and thereby shrinkage of the tissue under the mucous membrane, which has a comparable effect as removal of said tissue by surgery (UPPP or LAUP) since the vibrating tissue mass will be reduced.  
           [0014]    A still further object of the invention is to provide an apparatus of the kind referred to which allows focusing of the ultrasound energy to be adjusted in dependence of the location of the target area so that the ultrasound energy always will be focused on the target area.  
           [0015]    Said objects are achieved according to the invention by the apparatus according to claim  1  and the method according to claim q.  
           [0016]    In order to effect the treatment in a user friendly manner the exchangeable unit provides both a sterility barrier and a contact surface cooling the treatment site.  
           [0017]    The diagnostic part of the invention has also the possibility of controlling the result after each therapeutic pulse, in order to produce a well adjusted energy dose for creating shrinkage of the targeted tissue. The controlling system analyses the backscattered ultrasound signals from the area around the focus point. The analysis can be based on the amount of backscattered harmonics, Doppler-shift and the difference between echoes from positive and negative pulses of either diagnostic or therapeutic ultrasound energy from untreated tissue.  
           [0018]    Preferred embodiments of the invention are defined in the dependent claims.  
           [0019]    The invention will be described in more detail below with reference to the accompanying drawings showing illustrative embodiments of the invention. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWING  
       [0020]    [0020]FIG. 1 is a side view of a first embodiment of the apparatus of the invention,  
         [0021]    [0021]FIG. 2 is a plan view of an instrument forming part of the apparatus in FIG. 1 to be held by the operator the instrument being shown in a straight condition,  
         [0022]    [0022]FIG. 3 is a plan view of the instrument in FIG. 2 in a bent condition,  
         [0023]    [0023]FIG. 4 is a partial side view of the instrument in FIGS. 2 and 3, which is intended for multiple use,  
         [0024]    [0024]FIG. 5 is a side view of the part of the instrument shown in FIG. 4 with an element intended for one way use mounted thereon,  
         [0025]    [0025]FIG. 6 is an end view of the instrument,  
         [0026]    [0026]FIG. 7 is a cross sectional view taken along line A-A in FIG. 6,  
         [0027]    [0027]FIG. 8 is a cross sectional view taken along line B-B in FIG. 6,  
         [0028]    [0028]FIG. 9 is a cross sectional view taken along line C-C in FIG. 6,  
         [0029]    [0029]FIG. 10 is a partial cross sectional view according to FIG. 7 showing the instrument in a different adjusted position than that in FIG. 7,  
         [0030]    [0030]FIG. 11 is a side view of a second embodiment of the instrument of the invention,  
         [0031]    [0031]FIG. 12 is a plan view of the instrument in FIG. 11,  
         [0032]    [0032]FIG. 13 is an enlarged cross sectional view taken along line D-D in FIG. 11,  
         [0033]    [0033]FIG. 14 is an enlarged cross sectional view taken along line E-E in FIG. 12,  
         [0034]    [0034]FIG. 15 discloses different shapes of the transducer head in side view, and  
         [0035]    [0035]FIG. 16 is a block diagram of a control unit forming part of the apparatus of the invention, and  
         [0036]    [0036]FIG. 17 is a time diagram of the procedure applied when using the apparatus, 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0037]    The apparatus of the invention disclosed in FIGS.  1  to  3  comprises a control unit  10  and an instrument  11  to be held by the operator, which is connected with the control unit by a flexible hose  12  containing electric wiring and fluid conduits. The instrument forms a handle  13  and a stem  14  projecting from the handle. An ultrasonic transducer head  15  is provided at the free end of the stem, facing axially from the end.  
         [0038]    Referring also to FIGS.  4  to  10  the stem  14  comprises a series of individual elements  16  which are kept in mutual engagement at concave and convex surfaces by a helical tension spring  17  extending through the elements and being attached at the ends of the spring to end elements  16 A and  16 B. End element  16 A is connected with transducer head  15  while end element  16 B is connected with a bushing  18  which has outside threads  19  and is formed integral with or is attached to the handle  13 .  
         [0039]    An open-ended socket  20  is closed at one end by a flexible and resilient membrane  21  to be applied against a surface of the human body. At the other end socket  20  is connected to a flange  22 . A collar  23  integral with the flange forms an inside annular bead  24  which is snapped over an outside annular bead  25  on a socket  26 . Thus, socket  20  with membrane  21  can be separated from bushing  18  in order to be thrown away after use or be sterilized before it is used again. Socket  26  has inside threads  27  engaging the outside threads  19  of bushing  18 . Transducer head  15  comprises a piezo-electric crystal  28  forming a concave surface  29  which faces membrane  21  and is connected with two wires  30  which are extended through spring  17  and hose  12  to control unit  10  for the supply of electric current exciting crystal  28 . Socket  20  forms two axial passages  31 , FIGS. 6 and 7, connected to hoses  32  which are extended through hose  12  to control unit  10 . A fluid, water or air, can be circulated through passages  31  and the space defined by the concave surface  29  and membrane  21  in order to cool the crystal and the membrane as well as the body surface against which the membrane is applied during operation of the apparatus, but also to expand membrane  21  (see FIG. 8) for adjustment of the distance between the crystal and said body in order to focus the ultrasound energy emitted by the crystal, on the target area to be treated in the human body. Adjustment of the distance between the crystal and the body surface is effected by varying the pressure of the circulating fluid. An O-ring  33  seals said space defined by the concave surface  29  and the membrane  21 , against the interior of the stem. Optical fibers  34 A and  34 B are extended through axial passages  35  formed by socket  20 , FIGS. 6 and 8, and through hose  12  to transmit to the control unit  10  signals representative for the temperature of the membrane  21 . Fiber  34 A projects light against the back surface of the membrane  21 , which can be covered by a temperature sensitive paint that changes color in dependence of the temperature thereof, and the reflected light the color of which is thus dependent of the temperature of the membrane is transmitted to the control unit by fiber  34 B for processing in the control unit and indication of the temperature of the membrane.  
         [0040]    The temperature of membrane  21  also can be measured by other techniques known per se. E.g. a thermistor, resistor or a thermoelement can be integrated with the membrane.  
         [0041]    Socket  20  also forms axial passages  36 , FIGS. 6 and 9, which are connected to a vacuum pump in control unit  10  by conduits in hose  12  in order to provide a suction force on the surface against which the membrane is applied in order to keep the tissue thereof attracted against the membrane during operation of the apparatus.  
         [0042]    Socket  26  can be screwed on bushing  18  for supplementary adjustment of the distance between the body surface to which the membrane  21  is applied, and the crystal  28  as illustrated in FIG. 10. By this adjustment the relative position of socket  20  and crystal  28  is changed. As an alternative, means can be provided for displacement of crystal  28  in relation to socket  20  which in that case is fixedly mounted.  
         [0043]    Referring to FIG. 16 the control unit  10  comprises a transmitter  101  for generating diagnostic ultrasound energy (low intense) which is transmitted by the crystal (transducer)  28 , and a transmitter  102  for generating therapeutic (high intense) ultrasound energy which is also transmitted by the crystal  28 . The two transmitter curcuits can also be constructed as a single circuit. By means of the apparatus described the ultrasound energy is transmitted to tissue T to be treated from the crystal via the membrane  29  which is applied against an outside surface of the tissue. A receiver  103  including a wideband amplifier with controlled amplification is provided for receiving and amplifying ultrasound echo signals. The receiver  103  is connected to a analogue/digital converter  104  for converting signals received by the receiver from analogue form to digital form in order to facilitate subsequent signal processing. Output signals from the receiver are transmitted via the converter to an analyzer  105  and to a calculator  106 . The analyzer  105  can be an FFT (fast Fourier transform) analyzer or a Doppler analyzer or correlating echoes from negative and positive transmitted ultrasound pulses. A single analyzer of one or a combination of the types mentioned can be provided. The output signal from the analyzer (or each analyzer) is transferred to a complex comparing curcuit here called “a comparator”  107  wherein the signal is compared with a reference earlier stored. The comparator  107  is operatively connected with the transmitter  102 . When a comparison indicates that the input signal equals a pre-set reference value the comparator shuts of the transmitter  102 . A display  108  is connected to the calculator  106  and the comparator  107 .  
         [0044]    When the apparatus described is to be used for treatment of a patient the membrane  21  of the instrument  11  is applied against an outside front surface A of the tissue T. By means of diagnostic ultrasound signal pulses generated by the transmitter  101  and transmitted by the crystal  28  via the membrane  21  ultrasound echoes generated by ultrasound energy being reflected at the front and back surfaces A and B, respectively, of the tissue are received by the receiver  103  and are processed in the calculator  106  in order to determine the thickness of the tissue T. The echoes are also transmitted to the comparator  107  via an analyzer  105  of the FFT type for analysis of harmonics in the echo signals or to an analyzer  105  of the Doppler type for analysis of “movements” in the target area, or analysis of echoes from transmitted positive and negative pulses, or to a combination of analyzers of one and the other type, respective, and the output signal(s) from the analyzer(s) is received by the comparator  107 .  
         [0045]    With reference to FIG. 17 which illustrates diagrammatically a typical sequence for effecting a non-invasive ultrasonic medical treatment according to the invention the several steps being marked on a time axis. Initially the thickness of the tissue between surfaces A and B is defined between positions  1  and  2 . Echoes are received when the ultrasound passes through the front surface A and when the ultrasound passes through the back surface B. The distance between the surfaces is calculated in the calculator  106  on the basis of the time period between the echoes and the frequency of the ultrasound. The target area F to be treated usually is located substantially midway between the first and second surfaces. On the basis of the result of the measurement the distance between the crystal  28  and the membrane  21  applied against the tissue surface A is now adjusted in order to focus ultrasound energy emitted by the crystal  28  on the target area F located centrally in the tissue. This can be done by adjusting the pressure of the circulating fluid in order to expand the membrane  21  more or less and/or by adjusting the relative axial position of socket  26  and crystal  28 . The pressure of the fluid is adjusted on control unit  10 . Then, therapeutic ultrasound energy generated by the transmitter  102  is transmitted from the crystal  28  via membrane  21  and is focused on the target area for treatment of the tissue in said area.  
         [0046]    Parameters of the treatment such as ultrasound intensity, temperature of the circulating fluid, etc are set on control unit  10 .  
         [0047]    Therapeutic ultrasound pulses are emitted from the apparatus for about 1.3 seconds and then there is a pause for a period of 8.7 seconds. This can also be scaled down by approximately a factor of 10. During the pause the result of the treatment is checked by using backscattered echoes from both the therapeutic and the diagnostic ultrasound pulse between end of pulse  2  and after the “analyzing-pulses” positions  3  and  4 . Depending on the result the non-invasive treatment is repeated according to the procedure described for 1 to 10 minutes until the desired amount of fibrous tissue in the target area has been developed which is indicated by the comparison made in the comparator. When the signal received by the comparator  107  equals a preset value which indicates that the desired amount of fibrous tissue has been developed by the treatment by means of therapeutic ultrasound, the transmitter  102  is shut off by a signal emitted by the comparator.  
         [0048]    A switch  38  is provided on handle  13  of instrument  11  for turning the apparatus on and off, and thus the therapeutic treatment can be interrupted at any time according to the judgement of the operator. Also light emitting diodes  39  are provided on the handle to indicate different phases of the treatment effected by means of the apparatus.  
         [0049]    Socket  20  including membrane  21  and flange  22  with collar  23  which during the treatment performed by means of the apparatus come into contact with the patient, should be constructed as an exchangeable unit for either one way use to be discarded after each use, or for sterilization after each use said unit being detached from the instrument at snap attachment  24 ,  28 . The remainder of the instrument which does not contact the patient should be constructed for multiple use.  
         [0050]    Referring now to FIGS.  11  to  15  in the drawings the instrument  11  disclosed therein comprises a handle  13  provided with switch  38  and indicators  39  and adapted to be connected to the control unit  10  by hose  12 . In this case the transducer head  15  is not facing axially from the end of the stem  14  but in the transverse direction thereof. The stem comprises a multiple lumen flexible hose  40  of silicone rubber receiving in a central lumen  41  thereof a metal maintain a shape which has been imparted to it.  
         [0051]    The transducer head comprises a bottom element  43  which is permanently attached to the hose  40 , and a cover element  44  which is connected by a snap connection  45  to the bottom element and forms together with the bottom element a sealed space enclosing the ultrasound crystal  28 . Element  44  in this case is a substantially rigid element forming a plane surface  44 A to be applied against a body surface, and thus does not allow the focusing of the emitted ultrasound energy to be adjusted in the manner described with reference to membrane  21 . However, such adjustment can be effected by attaching to the bottom element cover elements  44  of different axial lengths. It is also possible to replace the element  44  forming a plane surface  44   a  by an element forming a convex surface  44 B or an element forming a semi-spherical surface  44 C, FIG. 15. The wires  30  for connecting the crystal with the control unit are extended through lumens  46  and  47  in hose  40 . Lumens  48  and  49  form passages for supplying cooling fluid to the crystal space and draining cooling fluid therefrom. A lumen  50  receives a temperature sensor  51 , and a lumen  52  forms a suction passage for the purpose mentioned above.  
         [0052]    Cover element  44  is sealed to a flexible tubular sheath  53  which is extended over the hose  40  forming the stem of the instrument. The cover element and the sheath should form a unit for one way use to be detached at snap connection  45  and be discarded after each treatment of a patient. Said unit prevents hose  40  and bottom element  43  including details mounted therein, from contacting the human body during operation of the apparatus.  
         [0053]    Preferred embodiments have been described in order to illustrate the invention but it is obvious to the man skilled in the art that these embodiments are examples only and that modifications thereof can be made without departing from the scope of the invention as defined in the claims.