Patent Application
20140276201
This disclosure pertains to a detection system and method for determining the state of target tissue including the type of target tissue, the disease state of the target tissue, pathogen infection types and levels in the tissue, and biofilm presence to assist in the electrosurgical treatment of the target tissue, in particular, an electrosurgical treatment whereby an active electrode in the presence of plasma is directed to perforate and/or debride wound tissue, remove debris and pathogens from a wound bed, induce blood flow, and leverage the body's metabolic, vascular, molecular, and biochemical response to promote, stimulate, and stabilize the healing process.
Electrosurgical tissue treatment may be conducted on target tissue for a variety of reasons. The target tissue may be an organ or tissue structure requiring electrosurgical intervention or may be an infection field requiring surgical debridement or other electrosurgical intervention. Electrosurgical treatment may include removal of tumor tissue from organs or portions of the human body using energy-based surgical treatments such as laser ablation, cautery, plasma produced in liquid or gas plasma treatment applied to tumors as distinguished from the underlying organ or other tissue.
Similar treatment mechanisms may be applied to treatment of internal membranes such as those in otorhinolaryngological (ENT) applications. For example, sinuses may become infected severely enough to develop infection field biofilms that may be treated with electrosurgery. Ear, nose and throat infections are becoming more resistant to common treatment. This is due to the presence of biofilms which can be found in ear infections (with mucosal biofilms), as well as chronic sinusitis (also commonly related to biofilms). Biofilms have been demonstrated on tonsils, adenoids, and sinus locations and the biofilms interfere with the application of antibiotics. Electrosurgical removal of these biofilms in infected target treatment sites is advantageous for sterilization and promotion of healing.
Yet another example of electrosurgical treatment includes dermatological applications. One specific example of the use of electrosurgical treatment is treatment of chronic wounds. Wound healing is the body's natural response for repairing and regenerating dermal and epidermal tissue. Wound healing is generally categorized into four stages: 1) clotting/hemostasis stage; 2) inflammatory stage; 3) tissue cell proliferation stage; and 4) tissue cell remodeling stage. The wound healing process is complex and fragile and may be susceptible to interruption or failure, especially in the instance of chronic wounds. A wound that does not heal in a predictable amount of time and in the orderly set of stages for typical wound healing may be categorized as chronic.
Chronic wounds may become caught in one or more of the four stages of wound healing, such as remaining in the inflammatory stage for too long, and thereby preventing the wound healing process to naturally progress. Similarly, a chronic wound may fail to adequately finish one stage of healing before moving on to the next, resulting in interference between the healing stages and potentially causing processes to repeat without an effective end. By way of further example, during the stage of epithelialization in typical wound healing, epithelial cells are formed at the edges of the wound or in proximity to a border or rim surrounding the wound bed and proliferate over the wound bed to cover it, continuing until the cells from various sides meet in the middle. Affected by various growth factors, the epithelial cells proliferate over the wound bed, engulfing and eliminating debris and pathogens found in the wound bed such as dead or necrotic tissue and bacterial matter that would otherwise obstruct their path and delay or prevent wound healing and closure. However, the epithelialization process in chronic wounds may be short-circuited or ineffective as the epithelial cells, needing living tissue to migrate across the wound bed, do not rapidly proliferate over the wound bed, or in some instances do not adequately respond at all during this particular stage of wound healing. As such, a need arises with chronic wounds to sterilize the wound site, as well as to establish communication between healthy tissue and wound tissue to promote epithelialization, fibroblast and epithelial migration, and neovascularization, and to bridge the gaps (i.e., including but not limited to structural and vascular gaps) between vital tissue surrounding the wound bed and tissue on the periphery of and within the wound bed itself.
Certain chronic wounds can be classified as ulcers of some type (i.e., diabetic ulcers, venous ulcers, and pressure ulcers). An ulcer is a break in a skin or a mucus membrane evident by a loss of surface tissue, tissue disintegration, necrosis of epithelial tissue, nerve damage and pus. Venous ulcers typically occur in the legs and are thought to be attributable to either chronic venous insufficiency or a combination of arterial and venous insufficiency, resulting in improper blood flow and/or a restriction in blood flow that causes tissue damage leading to the wound. Pressure ulcers typically occur in people with limited mobility or paralysis, where the condition of the person inhibits movement of body parts that are commonly subjected to pressure. Pressure ulcers, commonly referred to as “bed sores,” are caused by ischemia that occurs when the pressure on the tissue is greater than the blood pressure in the capillaries at the wound site, thus restricting blood flow into the area.
For patients with long-standing diabetes and with poor glycemic control, a common condition is a diabetic foot ulcer, symptoms of which include slow healing surface lesions with peripheral neuropathy (which inhibits the perception of pain), arterial insufficiency, damage to small blood vessels, poor vascularization, ischemia of surrounding tissue, deformities, cellulitis tissue formation, high rates of infection and inflammation. Cellulitis tissue includes callous and fibrotic tissue. Thus, due to the often concomitant loss of sensation in the wound area, diabetic patients may not initially notice small, non-lesioned wounds to legs and feet, and may therefore fail to prevent infection or repeated injury. If left untreated a diabetic foot ulcer can become infected and gangrenous which can result in disfiguring scars, foot deformity, and/or amputation.
Example chronic wound beds 110 of a diabetic foot ulcer are illustrated in
Typically, ulcer treatment is dependent upon its location, size, depth, and appearance to determine whether it is neuropathic, ischemic, or neuro-ischemic. Depending on the diagnosis, antibiotics may be administered and if further treatment is necessary, the symptomatic wound bed area is treated more aggressively (e.g., by surgical debridement using a scalpel, scissors, or other instrument to cut necrotic and/or infected tissue from the wound, mechanical debridement using the removal of dressing adhered to the wound tissue, or chemical debridement using certain enzymes and other compounds to dissolve wound tissue) to remove unhealthy wound tissue and induce blood flow and to expose healthy underlying structure. Often, extensive post-debridement treatment such as dressings, foams, hydrocolloids, genetically engineered platelet-derived growth factor becaplermin and bio-engineered skins and the like may also be utilized.
Additionally, several other types of wounds may progress to a chronic, non-healing condition. For example, surgical wounds at the site of incision may progress inappropriately to a chronic wound bed or may progress to pathological scarring such as a keloid scar. Trauma wounds may similarly progress to chronic wound status due to infection or involvement of other factors within the wound bed that inhibit proper healing. Burn treatment and related skin grafting procedures may also be compromised due to improper wound healing response and the presence of chronic wound formation characteristics. In various types of burns, ulcers, and amputation wounds, skin grafting may be required. In certain instances, patients with ischemia or poor vascularity may experience difficulty in the graft “taking” resulting in the need for multiple costly skin grafting procedures.
Various methods exist for treatment of chronic wounds, including antibiotic and antibacterial use, surgical or mechanical debridement, irrigation, topical chemical treatment, warming, oxygenation, and moist wound healing, which remain subject to several shortcomings in their efficacy. Electrosurgical treatment such as electrosurgical debridement provides added benefits, but is still fraught with some difficulty. Determining the level or type of infection or presence of biofilms and infection is difficult to assess during electrosurgical treatment. This is especially true because the electrosurgical treatment removes and alters the target tissue by volumetric dissociation of the target tissue, biofilms, and pathogens present in the wound bed. Progress of the electrosurgical treatment in removal of target tissue is similarly difficult to assess by a surgeon to ensure removal of only desired targeted tissue and not healthy tissue or tissue of a type that is different from the target tissue. Location of biofilms, infection, or tissue types within a patient space of the wound bed or treatment site is also difficult to assess during electrosurgical treatment. Post-debridement treatment may also depend on the state of the wound tissue after electrosurgical treatment. Tissue or pathogen analysis may take hours or days which is untenable during an ongoing electrosurgical treatment. Accordingly, there remains a need for new and improved systems and methods for use in detecting and determining the type and state of target tissue during the treatment of target tissue, such as wounds, that address certain of the forgoing difficulties.
It will be appreciated that for simplicity and clarity of illustration, elements illustrated in the Figures have not necessarily been drawn to scale. For example, the dimensions of some of the elements are exaggerated relative to other elements. Embodiments incorporating teachings of the present disclosure are shown and described with respect to the drawings presented herein, in which:
Certain terms are used throughout the following description and claims to refer to particular system components. As one skilled in the art will appreciate, companies that design and manufacture electrosurgical systems may refer to a component by different names. Similarly, companies that develop and manufacture compound analysis systems may also refer to components by different names. This document does not intend to distinguish between components that differ in name but not function.
In the following discussion and in the claims, the terms “including” and “comprising” are used in an open-ended fashion, and thus should be interpreted to mean “including, but not limited to . . . . ” Also, the term “couple” or “couples” is intended to mean either an indirect or direct connection. Thus, if a first device couples to a second device, that connection may be through a direct connection or through an indirect electrical connection via other devices and connections.
Reference to a singular item includes the possibility that there are plural of the same items present. More specifically, as used herein and in the appended claims, the singular forms “a,” “an,” “said” and “the” include plural references unless the context clearly dictates otherwise. It is further noted that the claims may be drafted to exclude any optional element. As such, this statement serves as antecedent basis for use of such exclusive terminology as “solely,” “only” and the like in connection with the recitation of claim elements, or use of a “negative” limitation. Lastly, it is to be appreciated that unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.
“Active electrode” shall mean an electrode of an electrosurgical wand which produces an electrically-induced tissue-altering effect when brought into contact with, or close proximity to, a tissue targeted for treatment, and/or an electrode having a voltage induced thereon by a voltage generator.
“Electrosurgical treatment” shall mean any energy-based volumetric dissociation of tissue by proximity of the energy-based treatment application whether plasma based, transmission based, thermal or cautery based, fluid jet systems and including treatment from monopolar or bipolar active electrodes or other instrument generating a plasma-based treatment in fluid such as Coblation® technology, gas-based plasma treatment of tissue, surgical laser ablation, other ablation due to energy application, and cauterization tools of any typical shape used in surgical applications.
“Fragmentation” shall mean volumetric alteration of tissue by application of treatment whether that is “electrosurgical treatment” or non-electrosurgical treatment with tissue treatment systems including, motorized or mechanical tissue treatment systems, or conventional treatment with scalpel, scissors, or other instruments to cut target tissue such as necrotic and/or infected tissue. Additional examples include treatment of target tissue such as wound tissue with mechanical debridement using the removal of dressing adhered to target tissue such as wound tissue or chemical treatment of target tissue using certain enzymes and other compounds to dissolve target tissue.
“Chronic wound tissue” shall mean wound tissue that does not heal in an orderly set of stages and in a predictable amount of time, including but not limited to wound tissue attributable to diabetic ulcers, venous ulcers, pressure ulcers, surgical wounds, trauma wounds, burns, amputation wounds, irradiated tissue, tissue affected by chemotherapy treatment, and/or infected tissue compromised by a weakened immune system, or any combination of the above.
“Physiological tissue types” shall mean any type of human tissue, diseased or healthy, that may be subject to electrosurgical treatment including but not limited to epidermal, dermal and sub-cutaneous layers of skin, other epithelial tissue, mucus membrane tissue, sinus tissue, connective tissues, fat tissues, musculo-skeletal tissues, cartilages, connector structure, membranes, brain and nervous system tissue, brain and nervous system membranes, ophthalmic, organ tissues such as liver, renal, prostate, uterine, pulmonary, tonsil, adenoid, bladder, gall bladder, gastro-intestinal, esophageal, spleen, reproductive, vascular and cardiac organ tissue, tumor tissue, infection site tissue infected by a variety of pathogens, and other tissues.
Where a range of values is provided, it is understood that every intervening value, between the upper and lower limit of that range and any other stated or intervening value in that stated range is encompassed within the invention. Also, it is contemplated that any optional feature of the inventive variations described may be set forth and claimed independently, or in combination with any one or more of the features described herein.
All existing subject matter mentioned herein (e.g., publications, patents, patent applications and hardware) is incorporated by reference herein in its entirety except insofar as the subject matter may conflict with that of the present invention (in which case what is present herein shall prevail). The referenced items are provided solely for their disclosure prior to the filing date of the present application. Nothing herein is to be construed as an admission that the present invention is not entitled to antedate such material by virtue of prior invention.
In the drawings and description that follows, like parts may be marked throughout the specification and drawings with the same reference numerals, respectively. The drawing figures are not necessarily to scale. Certain features of the invention may be shown exaggerated in scale or in somewhat schematic form and some details of conventional elements may not be shown in the interest of clarity and conciseness. The present invention is susceptible to embodiments of different forms. Specific embodiments are described in detail and are shown in the drawings, with the understanding that the present disclosure is to be considered an exemplification of the principles of the invention, and is not intended to limit the invention to that illustrated and described herein. It is to be fully recognized that the different teachings of the embodiments discussed below may be employed separately or in any suitable combination to produce desired results.
Electrosurgical apparatus and systems adaptable for use with the present method include any energy-based electrosurgical treatment of target tissue. Electrosurgical treatment and associated instrument systems are defined above and may include ablation due to energy transmission, generation of a plasma in a liquid, gaseous plasma generation, and thermal or cautery systems. Additionally volumetric dissociation via surgical fluid jets, such as VersaJet® water jet systems, are considered “electrosurgical treatment” for purposes described herein. Some portion of the embodiments of the present methods include compound analysis techniques applied to gases sampled from target tissue treatment sites.
The tissue compound analysis portion of the embodiments of the present methods may result from gaseous sampling collected from treatment sites not yet subjected to electrosurgical treatment or subjected to treatment from non-electrosurgical systems. Example non-electrosurgical systems include tissue treatment with motorized or mechanical tissue treatment systems, or conventional treatment with scalpel, scissors, or other instruments to cut target tissue such as necrotic and/or infected tissue. Additional examples include treatment of target tissue such as wound tissue with mechanical debridement using the removal of dressing adhered to target tissue such as wound tissue or chemical treatment of target tissue using certain enzymes and other compounds to dissolve target tissue.
The tissue compound analysis portion of the embodiments of the present methods may also result from gaseous sampling collected from treatment sites in situ during electrosurgical treatment or from treatment sites after electrosurgical treatment to determine the state of the target tissue and the progress of treatment. In several embodiments described herein, the state of the target tissue or wound tissue may indicate several characteristics about the target tissue. Analysis of gaseous samples collected from the target tissue may include identification and distinction of the physiological type of tissue present in some embodiments. This analysis is useful in determination of what layer or tissue is being removed or treated or whether tumor tissue or healthy tissue is being treated. Indication of target tissue state in other embodiments relate to the healthy or diseased state of the tissue based on contrast with analysis of known healthy samples or correlative comparison with known diseased state tissue analysis. In other embodiments, determination of target tissue state may indicate the presence of specific types and concentration levels of pathogens or the presence or non-presence of biofilms. In yet other embodiments, determination of the target tissue state may indicate whether a target tissue has been subject to electrosurgical treatment or not.
The assignee of the present invention developed Coblation® electrosurgical technology. Coblation® is an electrosurgical treatment technology that shall serve as an example embodiment electrosurgical treatment for many of the invention embodiments discussed herein. It is understood that other electrosurgical treatment systems and methods as defined above may be employed as well. Similarly, in certain embodiments, the non-electrosurgical treatment systems and methods may also apply to the invention embodiments described herein.
Coblation® involves the application of a high frequency voltage difference between one or more active electrode(s) and one or more return electrode(s) to develop high electric field intensities in the vicinity of the target tissue. The high electric field intensities may be generated by applying a high frequency voltage that is sufficient to vaporize an electrically conductive fluid and form a vapor layer over at least a portion of the active electrode(s) in the region between the tip of the active electrode(s) and the target tissue. The electrically conductive fluid may be a liquid or gas, such as isotonic saline, Ringers' lactate solution, blood, extracellular or intracellular fluid, delivered to, or already present at, the target site, or a viscous fluid, such as a gel, applied to the target site.
When the conductive fluid is heated enough such that atoms vaporize off the surface faster than they recondense, a gas is formed. When the gas is sufficiently heated such that the atoms collide with each other causing a release of electrons in the process, or, the electric field is intense enough to promote the release of electrons from nearby surfaces, an ionized gas or plasma is formed (the so-called “fourth state of matter”). Generally speaking, plasmas may be formed by heating a gas and ionizing the gas by driving an electric current through it, or by shining radio waves into the gas. These methods of plasma formation give energy to free electrons in the plasma directly, and then electron-atom collisions liberate more electrons, and the process cascades until the desired degree of ionization is achieved. A more complete description of plasma can be found in Plasma Physics, by R. J. Goldston and P. H. Rutherford of the Plasma Physics Laboratory of Princeton University (1995), the complete disclosure of which is incorporated herein by reference. Plasma based electrosurgical treatment systems, methods and technology are illustrated and described in commonly owned U.S. Pat. Nos. 6,296,638, 6,589,237; 6,602,248 and 6,805,130 and U.S. patent applications such as U.S. Patent Publication No. 2009/0209958, the disclosures of which are herein incorporated by reference.
In one exemplary embodiment illustrated in
In the presently described embodiment, an active electrode is an electrode that is adapted to generate a higher charge density relative to a return electrode, and hence operable to generate a plasma in the vicinity of the active electrode when a high-frequency voltage potential is applied across the electrodes, as described herein. Typically, a higher charge density is obtained by making the active electrode surface area smaller relative to the surface area of the return electrode.
Power supply (26) comprises selection means (28) to change the applied voltage level. The power supply (26) can also include a foot pedal (32) positioned close to the user for energizing the electrodes (16a, 16b). The foot pedal (32) may also include a second pedal (not shown) for remotely adjusting the voltage level applied to electrodes (16a, 16b). Also included in the system is an electrically conductive fluid supply (36) with tubing (34) for supplying the probe (10) and the electrodes with electrically conductive fluid. Details of a power supply that may be used with the electrosurgical probe of the currently embodiment is described in commonly owned U.S. Pat. No. 5,697,909, which is hereby incorporated by reference herein.
As illustrated in
As will be appreciated, the above-described electrosurgical system and apparatus can applied to wound tissue treatment and equally well applied to a wide range of electrosurgical procedures including open procedures, intravascular procedures, urological, laparoscopic, arthroscopic, thoracoscopic or other cardiac procedures, as well as dermatological, orthopedic, gynecological, otorhinolaryngological, spinal, and neurologic procedures, oncology and the like. Several types of physiological tissue, as defined above, may be treated, both healthy and diseased. However, for several presently-described system embodiments and method embodiments, the electrosurgical treatments are discussed as relating to treat various forms of breaks in skin tissue and chronic surface tissue wounds, including but not limited to skin ulcers, mucus membrane ulcers, foot ulcers including diabetic foot ulcers, cellulitic tissue, venous ulcers, pressure ulcers, surgical wounds, trauma wounds, burns, amputation wounds, wounds exacerbated by immune compromised disease, and wounds associated with radiation and chemotherapy treatments.
The electrosurgical treatment system probe of the presently-described embodiment generates a gas or liquid based plasma in the vicinity of a treatment site. As the density of the plasma or vapor layer becomes sufficiently low (i.e., less than approximately 1020 atoms/cm3 for aqueous solutions), the electron mean free path increases to enable subsequently injected electrons to cause impact ionization within the vapor layer. Once the ionic particles in the plasma layer have sufficient energy, they accelerate towards the target tissue. This ionization, under these conditions, induces the discharge of plasma comprised of energetic electrons and photons from the vapor layer to the surface of the target tissue. Energy evolved by the energetic electrons (e.g., 3.5 eV to 5 eV average energy, with higher-energy electrons in the “tail” of the energy distribution function) can subsequently collide with a molecule and break its bonds, dissociating a molecule into free radicals, which then combine into final gaseous or liquid species. Often, the electrons are accelerated by the electric fields or absorb the radio wave energy by inverse Bremmstrahlung processes, and, because of their small mass do not equilibrate with the heavier ions and, therefore, are hotter than the ions. Thus, the electrons, which are carried away from the tissue towards the return electrode, carry most of the plasma's heat with them, allowing the ions to break apart the tissue molecules in a substantially non-thermal manner. Thus, the target tissue is fragmented. Among the byproducts of this type of ablation are volatile organic compounds (VOCs) and other gases released by the target tissue fragmentation. VOCs emitted from target tissue indicate presence of pathogens, levels of pathogens, presence of biofilms, and indicate types of physiological tissue as discussed below.
By means of this molecular dissociation (rather than thermal evaporation or carbonization), the target tissue structure is volumetrically removed through molecular disintegration of larger organic molecules into smaller molecules and/or atoms, such as hydrogen, oxygen, oxides of carbon, hydrocarbons and nitrogen compounds. This molecular disintegration completely removes the tissue structure, as opposed to dehydrating the tissue material by the removal of liquid within the cells of the tissue and extracellular fluids, as is typically the case with electrosurgical desiccation and vaporization. Further, because the vapor layer or vaporized region has relatively high electrical impedance, it minimizes current flow into the electrically conductive fluid. A more detailed description of these phenomena, termed Coblation®, can be found in commonly assigned U.S. Pat. Nos. 5,683,366 and 5,697,882, the complete disclosures of which are incorporated herein by reference.
In certain embodiments of the present method, the applied high frequency voltage can be used to fragment tissue in several ways, e.g., current can be passed directly into the target site by direct contact with the electrodes such to heat the target site; or current can be passed indirectly into the target site through an electrically conductive fluid located between the electrode and the target site also to heat the target site; or current can be passed into an electrically conductive fluid disposed between the electrodes to generate plasma for treating the target site. In accordance with the present method, the system of
In various embodiments of the present method, the electrically conductive fluid possesses an electrical conductivity value above a minimum threshold level, in order to provide a suitable conductive path between the return electrode and the active electrode(s). The electrical conductivity of the fluid (in units of milliSiemens per centimeter or mS/cm) is usually be greater than about 0.2 mS/cm, typically greater than about 2 mS/cm and more typically greater than about 10 mS/cm. In an exemplary embodiment, the electrically conductive fluid is isotonic saline, which has a conductivity of about 17 mS/cm.
It is understood that tissue fragmentation may be accomplished in other embodiments via any electrosurgical treatment or non-electrosurgical treatment in substitution or addition to the liquid plasma embodiment described above. Any electrosurgical treatment or non-electrosurgical treatment may be used prior to the gaseous sampling and analyzer phases of the system illustrated in
In various embodiments of electrosurgical treatment methods described herein, including the exemplary Coblation® method, the electrosurgical treatment and compound analysis system (8) removes ablation by-products and/or any excess electrically conductive fluid from the surgical treatment site such as a wound bed. In an example embodiment, removal of electrosurgical by-products may be via aspiration. Alternatively, for other electrosurgical treatment or non-electrosurgical treatment techniques, a gas such as VOC may be sampled for exposure to an analyzer. As depicted in the embodiment of
An example type of gas that may be sampled either during electrosurgical treatment, or from emissions from a target tissue site before, after or during electrosurgical treatment includes the volatile organic compounds (VOCs) referenced above. The VOCs sampled by the gaseous sampling instrument (40) may contain a signature combination of molecules that help identify the state of tissue in the target tissue site such as a wound bed. As described in additional detail below, analysis can provide a level of correlation to gas samples from tissue with known tissue status to provide diagnostic identification with varying degrees of certainty. The presence of certain VOC combinations (or other gases) may result from and indicate the electrosurgical treatment itself, for example Coblation® treatment in the present embodiment. Other VOCs or combinations of VOCs indicate physiological tissue type such as the categories of physiological tissue types described above. VOCs emitted from target tissues or generated during electrosurgical or other treatment may also indicate state of the tissue. The state of the tissue may include the presence of infection, biofilm, damaged tissue (e.g., necrotic), disease states, and tumor tissue based on VOCs or combinations of VOCs present. The level of VOCs present may also indicate levels of infection in a particular target tissue. Thus, sampling and analysis of VOCs can provide important diagnostic information before, during, and after the time of treatment of a target tissue to assist in the treatment administered.
Aspiration lumens (42) and (44) may also aspirate small pieces of tissue that are not completely disintegrated by the high frequency energy, or other fluids at the target site, such as blood, mucus, and other body fluids. Accordingly, the various embodiments of the present system include one or more aspiration lumen(s) (42) and (44) in the shaft, or on another instrument, coupled to a suitable vacuum source (not shown) for aspirating fluids from the target treatment site. In various embodiments, the gaseous sampling instrument (40) may also include one or more aspiration active electrode(s) (not shown) coupled to the aspiration lumen for inhibiting clogging during aspiration of tissue fragments from the surgical site.
The gaseous sampling instrument (40) provides separation of the solid pieces of tissue and liquid fluids from the gases to be sampled with a solid and liquid by-product trap (46). The aspiration vacuum draws the ablation by-product through the aspiration lumens (42) or (44) to the solid/liquid by-product trap (46). Gases to be sampled by the system rise to the headspace of the solid/liquid by-product trap (46) or are released from solution into the headspace by passing an inert gas such as nitrogen through the solid/liquid by-product in the trap (46). The aspirated gases are available for removal separate from the solid or liquid by-product in the trap (46) headspace via sampling aperture (48).
In certain embodiments, only gases may be sampled, such as the aspiration of those gases emitted from target tissue sites such as a wound bed. Gases may also be all that is sampled from other tissue fragmentation systems; whether electrosurgical treatments or non-electrosurgical treatments. Exposure to analyzer sensors, such as various “electronic nose” systems described below, may not necessarily require aspiration. In these cases, since no solid or liquid by-product is aspirated, a solid/liquid by-product trap (46) may not be required. Instead, the sampling aperture (48) may be in fluid communication with the headspace over the target tissue via an aspiration lumen (42) or (44). Alternatively, an analyzer sensor may be in fluid communication directly with the headspace over the target tissue with a sampling aperture (48) comprising a sampling interface structure with the analyzer sensor.
Gas sampled from the solid/liquid trap may also be passed through a hydrocarbon moisture trap (50) to remove moisture and prevent contamination of the next stages of the compound analyzer (60). Another description of related aspiration system embodiments can be found in commonly owned U.S. Pat. No. 6,190,381, the complete disclosure of which is incorporated herein by reference for all purposes.
The compound analyzer (60) of the disclosed electrosurgical treatment and compound analysis system (8) receives the gas sampled from the gaseous sampling instrument (40) via a connector and tubing. In an embodiment, the sample gas includes VOCs as described above. The compound analysis system may include one or more compound analysis phases to generate a compound analysis profile. In the example embodiment shown in
Another alternative embodiment of the compound analyzer (60) includes “electronic nose” systems. Electronic noses are sensitive instruments that detect VOCs and may be used as an alternative compound analyzer (60) to the GC-MS system described in the present embodiment. These instruments are designed to test and discriminate among VOCs without having to identify the individual chemical species present in the volatile mixture. They have an added benefit in that they are portable and have software to sort out the various signatures of sniffed VOCs to provide a compound analysis profile.
There are a range of “electronic nose” sensor technologies including conducting-polymer sensors, metal oxide sensors, metal-oxide silicon field-effect sensors, piezoelectric crystals, optical sensors, and electrochemical sensors. Use of these “electronic noses” have some common operational steps where an electronic sensor array picks up a signal from the sampled VOCs, the information is preprocessed, and then pattern recognition software is applied to identify what bacteria are associated with the detected VOCs. This identification may result from a “learning” process whereby VOCs are analyzed from a known compound or a combination of compounds and the resulting analysis is stored in a library. An extensive library will allow identification of a wide range of compounds.
Examples of three types of electronic nose are: AromaScan A32S® from Osmetech Inc., Libranose 2.1® from Technobiochip Inc., and PEN3® from Airsense Analytics. The AromaScan A32S® from Osmetech Inc. is an organic matrix-coated polymer-type 32 sensor array. AromaScan sensor responses are measured as a percentage of electrical resistance changes to current flow in the sensors, relative to a baseline resistance. The type of polymer can be varied to customize the sensor response.
The Libranose 2.1 from Technobiochip Inc. has eight chemical quartz microbalance sensors. These microbalance sensors are ultrasensitive and capable of measuring small changes in a mass on a quartz crystal. The crystals are oscillated with a voltage and the resonant frequency is sensed. VOCs may be identified depending on the mass sensed.
The PEN3 from Airsense Analytics uses ten metal oxide semiconductor sensors. The metal oxide semiconductor sensors are doped semiconductors that sense the oxygen exchange between the VOCs and the metal coating material of the sensor upon proximity of the VOC molecular gas with the sensor.
Returning to the GC-MS compound analyzer (60) illustrated in
The capillary column (66) is connected at the proximate end of the GC phase (62) to the MS phase (70) of the compound analyzer (60) of the example embodiment. In the example embodiment, the separated gas sample is received at the MS phase (70) from the capillary column (66) of the GC phase (62). The MS phase (70) includes an ionizer (72) to capture and ionize the gaseous molecular components of the gas sample as they arrive from the capillary column (66). The ionizer may be an electron-impact ionization source in one embodiment or other ionization methods to ionize the gaseous sample (e.g., VOCs). A focuser (74) accelerates the portions of ionized gas sample into the deflector (76) and detector (78) of the MS phase (70) of the compound analyzer embodiment (60). The deflector (76) includes charged plates to create an electric and/or magnetic field that separate the ionized portions of the gaseous sample as they arrive at the MS phase (70) by mass-to-charge ratios. These separated ionized components are then detected at the detector (78) and data counts (intensity) and retention time are reported to a computer processing system (84) via data port (80) connected. The data port (80) is connected to an input port (82) on the computer processing system (84) via a cable, wireless connection, infrared connection, or other data connection. The computer processing system (84) then processes and prepares the data received from the detector (78).
In the example embodiment, compound analysis profiles (86) of the gaseous sample are developed and displayed as a function of intensity level (e.g., in nanograms) per retention time (e.g. in minutes) by the computer processing system (84). In alternative embodiments, compound analysis profiles derived from “electronic nose” systems may be used although they may not specifically identify each individual compound. Instead, these systems can take a broader analysis of a plurality of signature VOCs to determine a qualitative tissue state. The compound analysis profiles (86) may also include a table describing the detected compounds according to charge-to-mass ratios and retention times commonly measured by the compound analyzer (60) of the present embodiment. A determination of intensity levels for one or more compounds may also be provided in the compound analysis profiles.
Comparison between the compound analysis profile (86) measured in the gas sample and a database of known compound analysis profiles stored in a database (not shown) may be made by the computer processing system (84) as well. Correlation of profile data measured from the gaseous sample and known compound analysis profiles may be made to yield an estimation of the composition of the sampled target tissue from which the VOC or other gas sample was collected. For example, if a measured compound analysis profile (86) from the gas sample taken from a wound bed is found to correlate 85% with the signature compounds of a known compound analysis profile of an MRSA infected wound, then the computer processing system (84) may provide a diagnosis of the wound bed tissue corresponding to an 85% correlation to MRSA infection. A measure of comparative correlation provides a measure of certainty in the diagnosis made with the VOC compound analysis. Intensity levels of peaks or combinations of peaks that are signatures to MRSA may also provide data to relate potential infection levels or concentrations in pathogen colony forming units (CFU).
In an alternative embodiment, the computer processing system may compare the compound analysis profile (86) from a gas sample from a wound bed with that of a gas sample emitted from known healthy tissue of a similar type to the wound (e.g., a contra-lateral foot without a chronic wound). Comparison of the healthy tissue may be used to determine the disease state of the wound bed based on the correlation of gas samples from the wound bed contrasted with those gathered from the known healthy tissue. Further compound analysis processing embodiments by the computer processing system (84) to assist in treatment diagnoses are discussed below.
Examples of one embodiment of an electrosurgical treatment apparatus that can be used to fragment and treat tissue in accordance with the present method are illustrated in
In addition, the shape of the electrode at the distal end of the instrument shaft will also depend on the size of the chronic wound tissue surface area or other target tissue treatment site. For example, the electrode may take the form of a pointed tip, a solid round wire, or a wire having other solid cross-sectional shapes such as squares, rectangles, hexagons, triangles, star-shapes, or the like, to provide a plurality of edges around the distal perimeter of the electrodes. Alternatively, the electrode may be in the form of a hollow metal tube or loop having a cross-sectional shape that is round, square, hexagonal, rectangular, or the like. The envelope or effective diameter of the individual electrode(s) ranges from about 0.05 mm to 6.5 mm, preferably from about 0.1 mm to 2 mm. Furthermore, the electrode may in the form of a screen disposed at the distal end of the shaft and having an opening therethrough for aspiration of excess fluid and ablation byproducts.
With reference to
With reference to
Referring now to
Referring now to
Referring now to
In a typical procedure involving treatment of a chronic wound according to an embodiment of the present method, it may be necessary to use a series of electrosurgical treatments in combination with compound analysis to determine progress and next steps for treatment of the wound. For example, in a first step, an electrode of the type illustrated in either
Typically, during debridement procedures that utilize an electrode configuration of the type illustrated in
Applicants believe that the presently-described methods of treatment, VOC sample collection, and compound analysis for wound tissue utilizing the above-referenced electrosurgical devices, gas sample collection devices, and analyzer devices evokes a more organized and coordinated healing response than is typically associated with wound treatments. Specifically, the application of high frequency voltage and resulting plasma to wound tissue for debridement, in conjunction with analysis of pre-treatment, in situ, or post-treatment tissue status using compound analysis techniques to gases such as VOCs retrieved from the treatment site provides critical information relating to progress of electrosurgical treatment. This permits diagnosis for more accurate next steps of treatment of the wound.
The voltage difference applied between the return electrode(s) and the return electrode is high or radio frequency, typically between about 5 kHz and 20 MHz, usually being between about 30 kHz and 2.5 MHz, preferably being between about 50 kHz and 500 kHz, more preferably less than 350 kHz, and most preferably between about 100 kHz and 200 kHz. The RMS (root mean square) voltage applied will usually be in the range from about 5 volts to 1000 volts, preferably being in the range from about 10 volts to 500 volts depending on the active electrode size, the operating frequency and the operation mode of the particular procedure or desired effect on the tissue (e.g., contraction, coagulation, cutting or ablation).
Typically, the peak-to-peak voltage for ablation or cutting of tissue will be in the range of from about 10 volts to 2000 volts, usually in the range of 200 volts to 1800 volts, and more typically in the range of about 300 volts to 1500 volts, often in the range of about 500 volts to 900 volts peak to peak (again, depending on the electrode size, the operating frequency and the operation mode). Lower peak-to-peak voltages will be used for tissue coagulation or collagen contraction and will typically be in the range from 50 to 1500, preferably from about 100 to 1000, and more preferably from about 120 to 600 volts peak-to-peak.
Streptococcus
pyogenes
E. coli +
pseudomonas
E. coli +
pseudomonas
E. coli +
pseudomonas
Streptococcus
pyogenes
Streptococcus
pyogenes
In Tables 2A and 2B (below), corresponding data relating to the compound analysis profiles, including retention time peaks (530), shown in
As can be seen in Table 2A, limited change occurred between the compound analysis profiles of
With reference to
At (630), the gaseous by-product sample is injected into an analyzer, such as GC-MS analysis or an analyzer utilizing an electronic nose system such as those described above for detecting VOCs. The detector of the analyzer system provides data relating to the components of the gaseous by-product sample to a processing system for determination of a compound analysis profile at (635). The processor may then make a comparison at (640) to correlate the measured compound analysis profile with a database of known compound analysis profiles. Correlative analysis may be done at (645) to provide an estimate of the match with the known profiles. For example, a range of correlation between the compound analysis profile of data table entries (or peaks) of the measured gaseous by-product sample may be made. The correlation range may reflect a determination of how close to a 100% match the compound analysis profile of the measured sample is to the known compound analysis profile signatures. The known compound analysis profiles correspond to tissue status characteristics such as tissue types, pathogens, and biofilms. The percentage correlation provides an indication of certainty of the diagnostic match.
Proceeding to (650), a diagnosis correlation with the known compound analysis profile is provided to assist with determination of future treatment action, if any. It provides an indication of wound tissue status relatively concurrently with the electrosurgical treatment. At (655), intensity levels of signature peaks or table entries may also diagnose infection levels for pathogens present at the treatment site.
Referring now to
When correlating pre-treatment compound analysis profiles of gas samples to known compound analysis profiles at (740), correlation may be made based on known signatures of physiological tissue types, pathogen types, or biofilms. In one embodiment, correlative analysis for diagnosis may include a correlative range of the percentage match values with one or more a known compound analysis profiles. For example, a plurality of known compound analysis profiles for a given tissue status characteristic may be used as a known comparison basis rather than only one compound analysis profile. Thus, the measure compound analysis profile may be compared to a range of expected analysis values corresponding to a tissue state.
The correlation level and the corresponding tissue status are then provided at (745). The correlation level between the measured compound analysis profile data table entries (or peaks) and known compound analysis profile data shows how close that the measured profile is to a 100% match. This, in turn, provides a relative level of certainty that the measured VOCs emitted from the target tissue indicate a characteristic tissue type, pathogen, or biofilm at the target tissue. The above correlation and association with tissue status and characteristics is a diagnosis of the target tissue. The diagnosis assists with determination of the outcome of current treatment and the course of future treatment action, if any. In the described embodiment, the correlative diagnosis provides an indication of wound tissue status relatively concurrently with the electrosurgical treatment in situ or shortly before or after treatment. Similar to the method embodiment shown in
Proceeding to block (750) from block (735) begins a second pass through the method embodiment (700) of
Proceeding to block (760) begins the third pass of the method embodiment (700). At (760), an aspiration lumen and a sampling aperture gathers a post-treatment emitted gaseous sample from a target tissue location after electrosurgical treatment, or alternatively non-electrosurgical treatment. The flow then proceeds back to block (730) where the post-treatment emitted gaseous sample is injected into an analyzer for determining a compound analysis profile at (735). This compound analysis profile of the post-treatment emitted gaseous sample is compared to known compound analysis profiles at (740) for correlation and diagnosis as described above. The post-treatment compound analysis profile may also be compared to a pre-treatment or in situ measurement compound analysis profiles at (745) to contrast the profiles and determine progress of the electrosurgical treatment. In another embodiment, a comparison may be made with a previous post-treatment emitted gaseous sample from an earlier round of electrosurgical treatment to assess ongoing progress of the rounds of electrosurgical treatment. In yet another embodiment, comparison may be made with a control sample of healthy tissue gases at (745) to determine differences and ongoing disease state of the treated tissue, if any. The third pass of the method embodiment 700 may end at this point.
An alternative embodiment includes optical navigation and detection systems. Optical navigation systems use a pair of fixed position cameras that interact with an instrument such as an electrosurgical device having three or more LEDs positioned on the instrument. The LEDs are tracked with about the same accuracy as the electromagnetic systems. Tracking and display software monitors the target tissue zones (830) and instrument location relative to patient space for the treatment site or wound bed (110).
Referring now to
Proceeding to (910), molecular gaseous samples for each target tissue zone may be gathered and sampled pre-treatment, in situ during treatment, or post-treatment according to several methods and techniques described above. At (915), the molecular gaseous samples associated with each target tissue zone are injected into a compound analyzer to determine compound analysis profiles for each tissue target zone. Alternatively, the molecular gases may be exposed to an electronic nose compound analyzer embodiment. A computer processor system may then compare the compound analysis profiles for each target tissue zone with known compound analysis profiles. Alternatively, comparison may be made with other measured pre-treatment, in-situ, or post-treatment compound analysis profiles from the same or nearby target tissue zones. Proceeding to (925), the system may then map and display diagnostic results and correlations for each target tissue zone in the target tissue wound bed. At (930), the location of an electrosurgical treatment device, energy-based transmission target, or non-electrosurgical treatment device may be detected by the treatment site navigation system. The location of the electrosurgical treatment device, transmission target, or other device is displayed relative to the diagnostic map of the segmented target tissue bed zones. The location of the fragmentation treatment instrument in the wound bed and the current tissue state diagnosis at that and nearby locations will greatly assist treatment decisions. At decision diamond (935), it is determined whether re-mapping is needed for one or more target tissue zones. Remapping may be necessary due to treatment altering tissue at some target tissue zones. If repeat assessment is desired, the flow returns to block (910) to reassess the compound analysis profile for the zone from a current gaseous sample. If repeat assessment is not required, the method embodiment (900) ends.
While preferred embodiments of this disclosure have been shown and described, modifications thereof can be made by one skilled in the art without departing from the scope or teaching herein. The embodiments described herein are exemplary only and are not limiting. Because many varying and different embodiments may be made within the scope of the present inventive concept, including equivalent structures, materials, or methods hereafter thought of, and because many modifications may be made in the embodiments herein detailed in accordance with the descriptive requirements of the law, it is to be understood that the details herein are to be interpreted as illustrative and not in a limiting sense.
This application claims priority to U.S. provisional application No. 61/788,706, filed Mar. 15, 2013, entitled “SYSTEM AND METHOD FOR DETECTING TISSUE STATE AND INFECTION DURING ELECTROSURGICAL TREATMENT OF WOUND TISSUE”.
| Number | Date | Country | |
|---|---|---|---|
| 61788706 | Mar 2013 | US |
