Abstract:
An ultrasound surgical apparatus and associated methods of use enabling relatively pain-free wound debridement is provided. The apparatus is constructed from a tip mechanically coupled to a shaft. The shaft is mechanical coupled to an ultrasound transducer driven by a generator. The ultrasound tip possesses at least one radial surface, a cavity, or some other form of a hollowed out area, within at least one of the radial surfaces, and a cutting member at the opening of the cavity. A method of debriding a wound and/or tissue with the apparatus can be practiced by delivering ultrasonic energy released from the various surfaces of the vibrating tip to the wound and/or tissue prior to and/or while portions of the tip are scrapped across the wound and/or tissue.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
   This application is a continuation-in-part of U.S. patent application Ser. No. 11/741,726 filed Apr. 28, 2007, the teachings of which are hereby incorporated by reference, which is a continuation-in-part of U.S. patent application Ser. No. 11/449,220, filed Jun. 7, 2006, the teachings of which are hereby incorporated by reference. 
   This application is also a continuation-in-part of U.S. patent application Ser. No. 11/465,300 filed Aug. 17, 2006, the teachings of which are hereby incorporated by reference, which is a continuation-in-part of U.S. patent application Ser. No. 11/449,220, filed Jun. 7, 2006, the teachings of which are hereby incorporated by reference 

   BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates to an apparatus and method for debriding wounds and/or various tissues of the body such as, but not limited to, tumors, epithelial tissue, muscle, and/or cartilage with ultrasound energy. 
   2. Description of the Related Art 
   When confronted with wounded tissue, physicians and similar practitioners of medical arts have numerous devices and methods at their disposal. Treating the wound can be simply accomplished by placing a bandage on the wound as to prevent contaminants such as, but not limited, microorganisms and dirt from entering the wound. Exposing the wound to hyperbaric oxygen may also bring about a therapeutic effect. More persistent and/or chronic wounds can be treated with repeated administrations of negative pressure therapy. 
   Administering pharmaceuticals to the wound may also be utilized to treat wounded tissue. A therapeutic benefit may be obtained by preventing an infection from developing in the wounded tissue. Keeping the wound in an infection free state can be accomplished by administering various anti-microbial agents such as, but not limited to, antiseptics, antibiotics, antiviral agents, antifungal agents, or any combination thereof. Administering various growth factors to the wounded tissue may also elicit a therapeutic benefit by promoting the growth of new tissue. 
   In extreme situations, the practitioner may have to resort to surgery to treat the wounded tissue. Grafting transplanted and/or bioengineered tissue onto the wounded may be necessary with severe wounds. 
   More experimental treatments, such as exposing the wounded tissue to ultraviolet light, electricity, and/or ultrasound, are also available to the practitioner. For example, U.S. Pat. Nos. 6,478,754, 6,761,729, 6,533,803, 6,569,099, 6,663,554, and 6,960,173 teach methods and devices utilizing an ultrasound generated spray to treat wounded tissues. Methods and devices utilizing indirect contact with the wounded tissue via a liquid aerosol are disclosed in U.S. Pat. Nos. 7,025,735 and 6,916,296. As taught by U.S. Patent Applications 2004/0030254 and 2006/0241470, directly contacting the wounded tissue with an ultrasonically vibrating probe may also be utilized to elicit a therapeutic effect by debriding the wound. 
   SUMMARY OF THE INVENTION 
   Treating severe and/or chronic wounds can be especially difficult. Successful treatment often requires the repeated removal of necrotic and/or diseased tissue by surgical debridement. The painful nature of surgical debridement, however, results in poor patient compliance. In the case of an infected and/or inflamed wound, surgical debridement procedures may be even more painful. Instead of enduring the pain of the cure, the patient chooses to live with the wound. Allowing the wound to go untreated, the patient becomes at risk for developing an infection and/or other complications. As the complications increase in severity, the patient may experience a reduced quality of life. For instance, an untreated diabetic ulcer on a patient&#39;s foot may become so painful that patient has difficulty walking. 
   An ultrasound surgical apparatus and associated methods of use enabling relatively pain-free wound debridement is provided. The apparatus comprises a tip mechanically coupled to a shaft. The shaft is mechanically coupled to an ultrasound transducer driven by a generator. The ultrasound tip comprises at least one radial surface, a cavity or some other form of a hollowed out area within at least one of radial surfaces, and a cutting member at the opening of the cavity. 
   When driven or otherwise activated by the generator, the ultrasonic transducer induces ultrasonic vibrations within the tip, causing ultrasonic energy to be released from the various surfaces of the tip. Directly contacting a wound and/or tissue with the vibrating tip causes the ultrasonic energy emanating from the various surfaces of the tip to enter the wound and/or tissue. The ultrasonic energy entering the wound and/or tissue reduces sensitivity to pain. Releasing ultrasonic energy into a wound and/or tissue is suspected, but not known, to change the permeability of cellular membranes to ions and/or other molecules within the extracellular environment. Changing membrane permeability may disrupt ionic and/or other chemical gradients relied upon by the cells to respond to painful stimuli. 
   When the transducer is activated, ultrasonic energy is also released from the walls of the cavity. Configuring the walls of the cavity as to form a parabola in at least two dimensions may focus the ultrasonic energy emanating from the walls of the cavity towards the focus of the parabola. If the focus of the parabola lies outside the cavity, then the ultrasonic energy emitted from the cavity may be concentrated towards a point below the surface of the wound and/or tissue to be treated. Concentrating the ultrasonic energy emitted from the cavity at a point below the surface of the wound and/or tissue may elicited a greater change in the membrane permeability of deep cellular structures such as, but not limited to, axons and somas, further decreasing the sensation of pain in the wound and/or tissue to be treated. 
   As to facilitate the transmission of ultrasonic energy from the walls of the cavity to a wound and/or tissue to be treated, the cavity may be filled with a coupling medium. Any fluid capable of conducting ultrasonic vibrations may be used as a coupling medium such as, but not limited to, saline, water, alcohol, corn oil, vegetable oil, or any combination thereof. When the tip is ultrasonically vibrated, cavitations may form within the coupling. Additionally or in the alternative, the coupling medium within the cavity may be atomized into a spray. If a piezoelectric transducer is used to induce the substructure formed by the shaft and tip, or just the tip if the shaft is omitted, to vibrate approximately in resonance, then the voltage of the electrical signal driving the transducer will largely control the degree to which the coupling medium is cavitated and/or atomized. At low voltages, the coupling medium within the cavity will be cavitated to a small degree. As the voltage increases, the amount of cavitations within the coupling medium is increased. Further increasing the voltage will eventually induce atomization of the coupling medium. Regardless of whether the coupling medium within the cavity is atomized and/or cavitated, the presence of a coupling medium within the cavity may couple the transmission of ultrasonic energy released from the walls of the cavity to the wound and/or tissue to be treated. 
   Ultrasonic energy released from tip into the wound and/or tissue reduces sensitivity to pain. Thus by releasing ultrasonic energy into the wound and/or tissue prior to and/or simultaneously with debridement, the tip reduces the discomfort experienced by the patient during debridement. Various degrees of debridement may be achieved by scrapping various portions of the surgical apparatus across the wound and/or tissue. For example, scrapping cutting members secured to the tip across the wound and/or tissue aggressively debrides diseased, necrotic, and/or other unwanted tissue. Cutting members may be located at the opening of the cavity and/or on the various surfaces of the tip. Ultrasonic energy released from the cutting members and/or the vibrations of the cutting members may fragment and/or emulsify the tissue being debrided, which may reduce the amount of force needed to be applied to cutting members to perform debridement. Furthermore, the ultrasonic energy released from and/or the vibrations of the cutting members permits aggressive debridement with a dull cutting edge. A moderate degree of debridement may be achieved by scrapping blunt edges within the tip across wound and/or tissue to be treated. Scrapping smooth surfaces of the tip across the wound and/or tissue to be treated may produce a mild debridement. 
   It should be noted and appreciated that other therapeutic benefits and/or mechanisms of actions, in addition to those listed, may be elicited by devices and methods in accordance with the present invention. The mechanisms of action presented herein are strictly theoretical and are not meant in any way to limit the scope this disclosure and/or the accompanying claims. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a perspective view of one embodiment of the surgical apparatus. 
       FIG. 2  depicts an embodiment of tip containing cutting edges affixed to a radial surface of the tip. 
       FIGS. 3   a - 3   c  illustrate embodiments of the apparatus depicting different possible configurations and orientations of the tip. 
       FIG. 4  illustrates an embodiment of the apparatus containing a distal surface. 
       FIG. 5  illustrates a cross-sectional view of one embodiment of the surgical apparatus. 
       FIGS. 6   a - 6   b  illustrate an embodiments of the surgical apparatus in which the coupling medium within the cavity is cavitated and atomized. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   As illustrated by the embodiment depicted in  FIG. 1 , the surgical apparatus comprises a surgical substructure  101  attached to an ultrasound transducer  102  driven by an electrical signal produced by generator  103 . As ultrasound transducers and generators are well known in the art, they need not, and will not for the sake of brevity, be described in detail herein. However, generator  103  should be capable of producing an electrical signal of a sufficient voltage to drive transducer  102  to induce substructure  101 , or tip  105  if shaft  104  is omitted, to vibrate approximately in resonance, with the amplitude of the vibrations being between approximately 1 micron and approximately 100 microns. Surgical substructure  101  may be capable of vibrating approximately in resonance at a frequency between approximately 15 kHz and approximately 3 MHz. Preferably, substructure  101  should be capable of vibrating approximately in resonance at a frequency of approximately 30 kHz. 
   Surgical substructure  101  is comprised of shaft  104  and tip  105 . As illustrated by the embodiment depicted in  FIG. 1 , shaft  104  contains a proximal surface  106  opposite a distal surface  107  and at least one radial surface  108  extending between proximal surface  106  and distal surface  107 . The proximal surface  106  of shaft  104  is mechanically coupled to transducer  102 . Distal surface  107  of shaft  104  is likewise mechanically coupled to tip  105 . Mechanically coupled to transducer  102  and tip  105 , shaft  104  transmits ultrasonic vibrations generated by transducer  102  to tip  105 . Shaft  104  may be mechanically coupled to transducer  102  by mechanically attaching (for example securing with a threaded connection), adhesively attaching, and/or welding it to transducer  102 . Alternatively, shaft  104  and transducer  102  may be a single piece. Likewise, shaft  104  may be mechanically coupled to tip  105  by mechanically attaching (for example securing with a threaded connection), adhesively attaching, and/or welding it to tip  105 . Alternatively, shaft  104  and tip  105  may be a single piece. As to facilitate the mechanical attachment of shaft  104  to tip  105 , tip  105  may, but need not, posses a shaft  117  or equivalent extension providing a point of attachment. 
   As illustrated by the embodiment depicted in  FIG. 1 , tip  105  comprises radial surfaces  109  and  110 , a cavity  111  containing an opening  112  within the radial surface  109 , and a cutting member  113  at opening  112 . Though not illustrated, it would be possible for radial surface  110  to extend to opening  112  such that cavity  111  would open in radial surface  110 . Providing a smooth edge that may be scrapped across a wound and/or tissue, radial surface  110  enables mild debridement. A moderate degree of debridement may be achieved by scrapping blunt edge  116  formed by the intersection of radial surfaces  109  and  110  across the wound and/or tissue to be treated. Scrapping cutting member  113  over a wound and/or tissue permits aggressive debridement. Though the particular cutting member  113  illustrated in  FIG. 1  is formed by sharpening a region of radial surface  109  into an edge, the cutting member at the opening of the cavity need not be so fashioned. The cutting member may be a separate piece secured to a surface of tip  105  into which cavity  111  opens. 
   Aggressive debridement may also be achieved by scrapping a cutting member attached to at least one of the surfaces of the tip across the wound and/or tissue to be treated.  FIG. 2  depicts an embodiment of tip  105  containing cutting edges  201  and  202  affixed to radial surface  110 . As illustrated, cutting member  201  is sharpened into an edge, while cutting member  202  is sharpened into a point. Though sharpened to some degree, cutting members  113 ,  201 , and  202  need not be so sharp as to cut and/or debride in the absence of ultrasonic vibrations. A plurality of cutting members may be attached to a surface of tip as to give the surface a rough and/or jagged appearance. Furthermore, cutting members attached to the surfaces of tip comprising a sharpened edge may run in any direction, and need not run the length of the surface to which they are attached. 
   Tip  105 , as illustrated in  FIGS. 1 and 2 , may contain a region  114  that is wider than the shaft  104  in two dimensions (y and z) oriented orthogonal to the longitudinal axis  115  of shaft  104 . Though not illustrated, it should be readily appreciated by those of ordinary skill in the art that tip  105  may be constructed as to possess a region wider than shaft  104  in only one dimension oriented orthogonal to longitudinal axis  115 . Furthermore, tip  105  may also be constructed as to lack any region wider than shaft  104  in a dimension oriented orthogonal to the longitudinal axis  115 . 
   Radial surfaces  109  and  110  of the illustrated embodiment of tip  105  form a multidimensional parabola. As such, the illustrated embodiment of tip  105  is characterized by a general paraboloid structure. As illustrated by the embodiments depicted in  FIGS. 3   a  and  3   b , the plane  301  of opening  112  need not be parallel to the longitudinal axis  115  of shaft  104 . It is also possible, as illustrated by the embodiment depicted in  FIG. 3   c , for the radial surfaces of the tip to form a two dimensional parabola. If the two dimensional parabola is extended in a third dimension, as illustrated in  FIG. 3   c , tip  105  may be characterized by a general vaulted configuration. 
   It should be appreciated from  FIG. 3   c  that the tip of the surgical apparatus may be comprised of more than two radial surfaces. Tip  105  may also contain a distal surface  401 , as illustrated by the embodiment depicted in  FIG. 4 . In the depicted embodiment, opening  112  of cavity  111  extends from distal surface  401  to radial surface  109 . The depicted cutting member  402  at the opening of cavity  111  is formed by sharpening a region of radial surface  109  and distal surface  401 . As with the embodiment depicted in  FIG. 1 , cutting member  402  may be a separate piece secured to radial surface  109 , distal surface  401 , and/or any other surface into which cavity  111  opens. Furthermore, the cutting member however fashioned and/or formed need not extend onto an additional surface from that on which it originates. 
     FIG. 5  illustrates a cross-sectional view of one embodiment of the surgical apparatus. As illustrated, wall  501  of cavity  111  may form a multidimensional parabola such that cavity  111  is characterized by a general paraboloid configuration. It is also possible, as illustrated in  FIG. 3   c , for the walls of cavity  111  to form a two dimensional parabola extended in a third dimension such that cavity  111  is characterized by a general vaulted configuration. In the embodiment illustrated in  FIG. 5 , the plurality of cutting members  502  encircling opening  112  of cavity  111  enables aggressive debridement. Moderate debridement may be achieved by scrapping the blunt edge provided the by the intersection of the inner surface of channel  503 , located at the base of cavity  111 , and radial surface  110  across the wound and/or tissue to be treated. 
   As to facilitate the transmission of ultrasonic energy emanating from the wall  501  of cavity  111  when a wound and/or tissue is debrided with a cutting member, edge, and/or surface at opening  112 , cavity  111  may be filled with a coupling medium  504 . Filling cavity  111  with coupling medium  504  may be made possible by delivering coupling medium  504  through channel  505 , which contains an opening within radial surface  108  of shaft  104  and runs through a portion of the shaft  104  before opening within wall  501  of cavity  111 , and/or channel  506 , which extends through transducer  102  and shaft  104  before opening into cavity  111 . In addition to filling cavity  111  with coupling medium  504 , channel  505  and/or  506  may used to extract coupling  504  and/or debris accumulating in cavity  111  during debridement such as, but not limited to, fragmented and/or emulsified tissue. 
   As depicted in  FIG. 6   a , cavitations  601  may be formed in coupling medium  504  if the generator driving transducer  102  produces an electrical signal of a sufficient voltage. If the voltage of the electrical signal is further increased, coupling  504  will atomize into spray  602 . If the walls of cavity  111  form a parabola in at least two dimensions, atomized spray  602  and/or the ultrasonic energy emanating from the walls of cavity  111  may be focused towards focus  603  lying outside cavity  111 . Positioning focus  603  outside cavity  111  may enable the ultrasonic energy emitted from the walls of cavity  111  to be concentrated towards a point below the surface of the wound and/or tissue being treated. Focus  603  may also be positioned within cavity  111  or in the plane of opening  112 . 
   It should be appreciated that elements described with singular articles such as “a”, “an”, and/or “the” and/or otherwise described singularly may be used in plurality. It should also be appreciated that elements described in plurality may be used singularly. 
   Although specific embodiments of apparatuses and methods have been illustrated and described herein, it will be appreciated by those of ordinary skill in the art that any arrangement, combination, and/or sequence that is calculated to achieve the same purpose may be substituted for the specific embodiments shown. It is to be understood that the above description is intended to be illustrative and not restrictive. Combinations of the above embodiments and other embodiments as wells as combinations and sequences of the above methods and other methods of use will be apparent to individuals possessing skill in the art upon review of the present disclosure. 
   The scope of the claimed apparatus and methods should be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled.