Endoscopic instrument for tissue identification

Abstract

A method for identifying and treating tissue includes providing an electrosurgical treatment device including an electrode assembly. One or more electrical property values of target tissue are measured. The measured electrical property values of the target tissue are compared against electrical property values of known tissue types. A tissue type of the target tissue is identified. An energy delivery configuration of the electrosurgical treatment device is adjusted to the type of target tissue. The electrosurgical treatment device is activated to treat the target tissue.

Claims

1. A method for identifying tissue, the method comprising: contacting tissue with at least one jaw member of a pair of opposed jaw members; applying an electrical signal to the tissue through a first electrode coupled to the pair of opposed jaw members; receiving, through a second electrode coupled to the pair of opposed jaw members, an electrical signal emitted by the tissue in response to the electrical signal applied to the tissue; determining an electrical property of the tissue based on the electrical signal emitted by the tissue; and comparing the determined electrical property of the tissue with at least one known electrical property to identify a type of the tissue.

2. The method according to claim 1, further comprising adjusting a frequency of the electrical signal applied to the tissue through the first electrode based on the identified type of the tissue.

3. The method according to claim 1, further comprising adjusting a wave configuration of the electrical signal applied to the tissue through the first electrode based on the identified type of the tissue.

4. The method according to claim 1, further comprising identifying a condition of the tissue based on the comparison.

5. The method according to claim 1, further comprising controlling delivery of electrosurgical energy to the tissue via at least one of the pair of opposed jaw members based on the comparison.

6. The method according to claim 1, wherein determining the electrical property of the tissue includes determining an impedance of the tissue.

7. The method according to claim 1, wherein determining the electrical property of the tissue includes determining a conductance of the tissue.

8. The method according to claim 1, further comprising delivering electrosurgical energy to the tissue to treat the tissue and determining an electrical property of the treated tissue.

9. The method according to claim 1, wherein identifying the type of the tissue includes comparing the determined electrical property of the tissue with an electrical property of tissue that is adjacent the tissue to identify a type of the tissue.

10. The method according to claim 1, wherein the first electrode is coupled to a first jaw member of the pair of opposed jaw members and the second electrode is coupled to a second jaw member of the pair of opposed jaw members.

11. The method according to claim 1, wherein applying the electrical signal to the tissue includes applying the electrical signal when the pair of opposed jaw members are in a closed condition to grasp the tissue.

12. A method for identifying tissue, the method comprising: applying an electrical signal to tissue through a first electrode coupled to a pair of opposed jaw members; receiving, through a second electrode coupled to the pair of opposed jaw members, an electrical signal emitted by the tissue in response to the electrical signal applied to the tissue; determining an electrical property of the tissue based on the electrical signal emitted by the tissue; and comparing the determined electrical property of the tissue with at least one known electrical property to identify a type of the tissue.

13. The method according to claim 12, further comprising controlling delivery of electrosurgical energy to the tissue via at least one of the pair of opposed jaw members based on the comparison.

14. The method according to claim 12, wherein determining the electrical property of the tissue includes determining an impedance of the tissue.

15. The method according to claim 12, wherein determining the electrical property of the tissue includes determining a conductance of the tissue.

16. The method according to claim 12, further comprising adjusting at least one of a frequency or a wave configuration of the electrical signal applied to the tissue through the first electrode based on the identified type of the tissue.

17. The method according to claim 12, wherein the first electrode is coupled to a first jaw member of the pair of opposed jaw members and the second electrode is coupled to a second jaw member of the pair of opposed jaw members.

18. The method according to claim 12, wherein applying the electrical signal to the tissue includes applying the electrical signal when the pair of opposed jaw members are in a closed condition to grasp the tissue.

19. A method for identifying tissue, the method comprising: applying an electrical signal to tissue through at least one of a pair of opposed jaw members; receiving, through at least one of the pair of opposed jaw members, an electrical signal emitted by the tissue in response to the electrical signal applied to the tissue; determining an electrical property of the tissue based on the electrical signal emitted by the tissue; and comparing the determined electrical property of the tissue with at least one known electrical property to identify a type of the tissue.

20. The method according to claim 19, further comprising contacting the tissue with at least one of the pair of opposed jaw members.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Various embodiments of the subject instrument are described herein with reference to the drawings wherein:

(2) FIG. 1A is a left, perspective view of an endoscopic bipolar forceps including a multi-electrode assembly for measuring tissue impedance according to an embodiment of the present disclosure;

(3) FIG. 1B is a left, perspective of an open bipolar forceps including a multielectrode assembly for measuring tissue impedance according to an embodiment of the present disclosure;

(4) FIG. 2 is a schematic illustration of an electrosurgical system including the endoscopic bipolar forceps of FIG. 1A;

(5) FIG. 3 is an enlarged front view of a jaw member including the multielectrode assembly;

(6) FIG. 3A is an enlarged view of the indicated area of detail of FIG. 3;

(7) FIG. 4 is a side elevational view of the jaw member of FIG. 3;

(8) FIG. 5 is an enlarged front elevational view of an alternate embodiment of a jaw member including another multi-electrode assembly for measuring tissue impedance;

(9) FIG. 5A is an enlarged view of the indicated area of detail of FIG. 5;

(10) FIG. 6 is a side elevational view of the jaw member of FIG. 5;

(11) FIG. 7 is an enlarged front elevational view of yet another jaw member the present disclosure including yet another multi-electrode electrode assembly;

(12) FIG. 7A is an enlarged view of the indicated area of detail of FIG. 7;

(13) FIG. 8 is a side elevational view of the jaw member of FIG. 7;

(14) FIG. 9 is a perspective view of an alternate embodiment of an electrosurgical instrument extending through a working channel of an endoscope;

(15) FIG. 10 is an enlarged side view of the electrode assembly of the endoscopic device of FIG. 9;

(16) FIG. 11 is an enlarged end view of an alternate embodiment of an electrode assembly;

(17) FIG. 12 is an enlarged end view of another embodiment of an electrode assembly;

(18) FIG. 13A is a side view of another embodiment of an electrode assembly; and

(19) FIG. 13B is an enlarged distal end view of the electrode assembly of FIG. 13A.

DETAILED DESCRIPTION

(20) Referring now to FIGS. 1-4, an embodiment of an electrosurgical instrument according to the present disclosure is shown generally as bipolar forceps 100. Bipolar forceps 100 include a housing 120, a handle assembly 130, a rotating assembly 180, a trigger assembly 170 and an end effector assembly 110 that mutually cooperate to grasp, seal and divide tubular vessels and vascular tissue. Although the following disclosure focuses predominately on discussion of a bipolar forceps 100 for use in connection with endoscopic surgical procedures, an open forceps 100 are also contemplated for use in connection with traditional open surgical procedures and are shown by way of example in FIG. 1B. For the purposes herein, the endoscopic version is discussed in detail; however, it is contemplated that open forceps 100 also include the same or similar operating components and features as described below.

(21) Bipolar forceps 100, 100 are substantially identical in form and function to bipolar forceps 10, 10 described in detail in commonly owned, U.S. Patent Publication No. 2007-0062017, the entire contents of which is hereby incorporated by reference herein. Thus, the form and function of bipolar forceps 100, 100 will be discussed only to the extent necessary to describe the improvement thereto. The aspects of the present disclosure may be incorporated into any suitable electrosurgical instrument.

(22) Turning now to FIGS. 1A and 2, forceps 100 includes a shaft 112 that has a distal end 114 dimensioned to mechanically engage the end effector assembly 110 and a proximal end 116 that mechanically engages housing 120. In the drawings and in the descriptions that follow, the term proximal, as is traditional, will refer to the end of the forceps 100 that is closer to the user, while the term distal will refer to the end which is further from the user.

(23) As seen in FIG. 1A, handle assembly 130 includes a fixed handle 160 and a movable handle 140. Fixed handle 160 is integrally associated with housing 120 and handle 140 is movable relative to fixed handle 160. Rotating assembly 80 is preferably attached to a distal end of housing 120 and is rotatable approximately 180 degrees in either direction about a longitudinal axis A.

(24) Turning briefly to FIGS. 3 and 4, end effector assembly 110 includes first and second jaw members 212, 214. First and second jaw members 212, 214 are operably connected to handle 140 (FIG. 1A). First and second jaw members 212, 214 are configured to approximate towards one another upon activation of handle 140. First and second jaw members 212, 214 cooperate to grasp and seal target tissue therebetween.

(25) As best seen in FIGS. 1A and 2, forceps 100 also include an electrical interface or plug 300 that connects the forceps 100 to a source of electrosurgical energy, e.g., a generator 10, and a processing unit 20. Generator 10 and processing unit 20 may be combined to form a single generator/processing unit 30. For ease of disclosure, further references to processing unit 20 may also be applicable to generator/processing unit 30. Generator 10 may be one of many sold by Valleylaba division of Tyco Healthcare LP, located in Boulder Colo., used as a source of electrosurgical energy, e.g., FORCE EZ Electrosurgical Generator, FORCE FX Electrosurgical Generator, FORCE 1C, FORCE 2 Generator, SurgiStat II. One such system is described in commonly-owned U.S. Pat. No. 6,033,399 entitled ELECTROSURGICAL GENERATOR WITH ADAPTIVE POWER CONTROL, the entire contents of which is hereby incorporated by reference herein. Other systems have been described in commonly-owned U.S. Pat. No. 6,187,003 entitled BIPOLAR ELECTROSURGICAL INSTRUMENT FOR SEALING VESSELS, the entire contents of which is hereby incorporated by reference herein.

(26) Generator 10 and/or generator/processing unit 30 may include various safety and performance features including isolated output, independent activation of accessories, and the Valleylab REM Contact Quality Monitoring System, which may substantially reduce the risk of burns under the patient return electrode. The electrosurgical generator may include Valleylab's Instant Response technology features that provide an advanced feedback system that senses changes in tissue 200 times per second and adjusts voltage and current to maintain appropriate power.

(27) Processing unit 20 is operably connected to an electrode assembly 50 (FIG. 3). As will be discussed in further detail below, electrode assembly 50 may be mounted on a distal end of forceps 100. Processing unit 20 operates in a manner similar to known tissue impedance measuring devices. Briefly, a predetermined energy signal is produced by processing unit 20 and applied to the target tissue (not explicitly shown) through electrode assembly 50. The resultant electrical response of the tissue to the signal may then be measured and converted into an impedance value. By comparing the tissue impedance measurements with known tissue impedance measurements processing unit 20 may determine the type of tissue being in contact with electrode assembly 50.

(28) The electrical current produced by processing unit 20 may vary depending on the type of tissue being identified. Processing unit 20 may configured to produce AC and/or DC current. Processing unit 20 may be configured to generate an electrical signal having a frequency ranging from RF (100 kHz) upwards of microwaves (low MHz to GHz). Depending on the application processing unit 20 may produce a signal of constant frequency, or may instead perform a frequency sweep. Bipolar forceps 100 may include more than one electrode assembly 50 connected to processing unit 20 for measuring tissue impedance. As will be discussed in further detail below, the one or more electrode assemblies 50 may include different electrode configurations depending on the tissue type and/or signal frequency being tested. Processing unit 20 may include any suitable methods of increasing the accuracy and consistency of the tissue electrical property measurements, e.g. filters and multi-frequency readings.

(29) Processing unit 20 may operate in a number of modes. Processing unit 20 may be configured to alert a user when electrode assembly 50 has contacted a specific tissue type. In this manner, a user would set processing unit 20 to scan for a particular tissue type. Processing unit 20 would produce an electrical signal configured for best identifying the tissue type. The electrical signal produced by processing unit 20 may be manually determined by the user or may instead be automatically determined by processing unit 20. The electrical signal produced may include a specific frequency or range of frequencies and/or may include a specific signal configuration. Electrode assembly 50 may be placed in contact over a portion of tissue. As electrode assembly 50 contacts tissue of the target type, as determined by processing unit 20 by comparing the electrical property measurements with known electrical property measurements of like tissue, processing unit 20 may alert the user. The alert may be audio and/or visual. An audio and/or visual indicator 22, 24 (FIG. 2) may be included in/on processing unit 20 and/or bipolar forceps 100.

(30) Identifying tissue type by comparing the electrical property measurements of the tissue with electrical property measurements from known tissue type requires the availability of electrical property measurements of known tissue. These measurements may not always be available, or may vary depending on the environment in which the target tissue is situated. For example, tissue located within the digestive tract and exposed to digestive enzymes may have different electrical property measurements from tissue exposed to air. When implementing the comparative technique described above, knowledge of the electrical property of the tissue exposed to digestive enzymes would be of little use when compared to the electrical properties of tissue exposed to air. When electrical property measurements of known tissue are not available, the type of tissue may be determined by comparing the electrical property measurements of the target tissue with the electrical property measurements of the surrounding tissue. Since fat exhibits different electrical properties from muscle, and muscles exhibits different electrical properties that connective tissue, by comparing the relative electrical property measurements of different tissue types within the same environment, i.e. saturated in digestive enzymes, or exposed to air, the differences in the relative electrical property measurements of the various tissues may be used to distinguish the various tissue types. Another example is the difference between a suspicious mass and the surrounding normal tissue may be used to determine its nature as benign or malignant.

(31) Alternatively, processing unit 20 may be configured to determine the type of tissue in contact with electrode assembly 50. In this manner, processing unit 20 produces an electrical signal spanning a wide range of frequencies and/or wave configurations. The range of frequencies and/or wave configurations may be limited by the user. As before, the tissue electrical property measurements (magnitude and/or phase) are compared against electrical property measurements for known tissue. Once processing unit 20 has determined the type of tissue the user may be alerted. The alert may be audio and/or visual.

(32) Once the type of tissue is known, whether through visual inspection or tissue impedance measurements, the condition of the tissue may also be determined. Using techniques similar to that described above, the condition of the tissue may also be determined. Knowing the type of tissue being examined is not necessary; however, it permits a user to limit the frequency range and/or signal configuration of the electrical signal applied to the tissue, thereby reducing the time for a result. The condition of the tissue may be determined by comparing the electrical property measurements with electrical property measurements of tissue of a known condition. In addition, the condition of the tissue may be determined by comparing the electrical property measurements of portions of the same tissue. Processing unit 20 may provide the user with an audio and/or visual alert as to the condition of tissue in contact with electrode assembly 50.

(33) Tissue has many electrical properties and there are many known methods for measuring these electrical properties. Although the following discussion will relate to a four-electrode method of measuring tissue impedance, other methods of measuring tissue electrical properties have been contemplated by the present disclosure. In the four-electrode method, four equidistant electrodes are placed in contact with or penetrate into the tissue to be tested. In one procedure utilizing the four-electrode method, a sinusoidal voltage is applied to the tissue across two electrodes and the resultant sinusoidal current flow through the tissue is measured. The magnitude of the tissue impedance may be determined as the ratio of the root-mean-square (RMS) voltage and the current values. The phase angle of the tissue impedance may be determined as the delay in radians of the peak sinusoidal current with respect to the peak sinusoidal voltage. By comparing the resulting impedance values with known values for various body tissue, the tissue type may be determined. It should be appreciated that the aspects of the present disclosure should not be limited to the methods of determining tissue impedance disclosed herein. Any suitable method for measuring tissue electrical properties may be incorporated into the embodiments of the present disclosure.

(34) Turning now to FIGS. 3-8, various embodiments of opposing jaw members including one or more multi-electrode assemblies that operate in a manner as discussed above are shown. Referring initially to FIGS. 3-4, end effector 110 of bipolar forceps 100 includes an electrode assembly 50. Electrode assembly 50 is mounted on a distal end 212b of first jaw member 212. As will be discussed below, alternate embodiments of bipolar forceps 100 may include a plurality of electrode assemblies mounted at various locations on first and/or second jaw members 212, 214. Electrode assembly 50 includes four electrodes 51, 52, 53, 54. In the illustrated embodiment, electrodes 51, 52, 53, 54 form substantially planar members having a substantially similar size and configuration. Electrodes 51, 52, 53, 54 are spaced an equidistance apart and may be formed of a metal, an alloy or other suitable material. Electrodes 51, 52, 53, 54 of electrode assembly 50 are operably connected to processing unit 20 (FIG. 3).

(35) In operation, electrodes 51, 52, 53, 54 of electrode assembly 50 are placed in contact with the tissue to be identified. First and second jaw members 212, 214 may be in an open or closed condition. Processing unit 20 produces an electric signal that is directed into the target tissue through outer electrodes 51, 54. Processing unit 20 may be configured to continuously produce a signal, or instead bipolar forceps 100 may include a button or lever 122, 124 mounted on housing 120 (FIG. 1A) and/or processing unit 20 (FIG. 2) for activating processing unit 20. As discussed above, depending on the application, the electric signal may be of a specific frequency or range of frequencies and of any configuration. The respective portion of tissue disposed between outer electrode 51 and inner electrode 52, and outer electrode 54 and inner electrode 53 functions to complete a circuit path therebetween. These portions of tissue produce characteristic tissue responses based on the signals delivered to electrodes 51, 52, 53, 54 by processing unit 20. The resulting tissue response is acquired by inner electrodes 52, 53. Also, as discussed above, the measurements of the tissue response may be used to calculate the tissue impedance. By comparing the tissue impedance values of the target tissue with impedance values of known tissue, the type of tissue being contacted (e.g., lung, liver, muscle, etc.) may be determined.

(36) As discussed above, once the tissue type has been determined, either through visual inspection, by comparing tissue electrical property measurements or with another suitable method, the condition of the tissue may also be determined. By directing an electric signal of a frequency or range of frequencies configured for the particular tissue type being tested and measuring the resultant impedance values, the condition of the tissue may be determined. For example, healthy tissue may be distinguished from cancerous tissue. Additionally, the stage of development of the cancer may also be determinable using the tissue impedance measurements.

(37) Once the tissue type and condition of the tissue have been identified, bipolar forceps 100 may operate as a conventional bipolar vessel sealer. The energy delivery configuration of generator 10 may be adjusted in accordance with the identified tissue type being sealed. The closure pressure of first and second jaw members 212, 214 may also be adjusted in view of the type of tissue being sealed and/or the condition of the tissue being sealed. While four electrodes, 51, 52, 53, 54 are shown as forming a part of multielectrode assembly 50, any suitable number of electrodes may be used either greater than or less than four in forming multi-electrode assembly 50.

(38) Turning now to FIGS. 5-6, in an alternate embodiment of an end effector of the present disclosure, end effector 220 includes electrode assembly 150 mounted on a distal end 212b of first jaw member 212. Alternately, electrode assembly 150 may be mounted on distal end 214b of second jaw member 214. Electrode assembly 150 includes electrodes 151, 152, 153, 154. Electrodes 151, 152, 153, 154 include piercing or penetrating members 151a, 152a, 153a, 154a, respectively, for penetrating the target tissue to be identified. By using piercing members 151, 152, 153, 154 to penetrate the tissue a relatively truer or more accurate tissue impedance measurement may be obtained. Piercing members 151a, 152a, 153a, and 154a may be of any suitable dimension and of any suitable configuration. In an alternate embodiment, electrodes 151, 152, 153, 154 and/or piercing members 151a, 152a, 153a, 154a may be selectively retractable and/or extendable.

(39) With reference now to FIGS. 7-8, in another embodiment of an end effector of the present disclosure, end effector 310 includes electrode assembles 250, 350, 450, and 550. Electrode assemblies 250, 550 are each substantially similar to electrode assemblies 50, 150 described hereinabove, and will therefore only be described as relates to the differences therebetween. Electrode assembly 250 or 550 includes an array of electrodes 251a-d, 252a-d, 253a-d, 254a-d arranged in any suitable configuration (e.g. rectilinear) and in any suitable quantity. Electrodes 251a-d, 252a-d, 253a-d, 254a-d of electrode assembly 250 are each operably connected to processing unit 20 (FIG. 2). Processing unit 20 may be configured to selectively apply electric signals through any or all of electrodes 251a-d, 252a-d, 253a-d, 254a-d in a manner similar to that described above to determine impedance of a target tissue. The rectilinear array of electrode assembly 240 enables a user to select the electrode configuration best suited for measuring and identifying tissue of a particular type.

(40) With continued reference to FIGS. 7-8, electrode assemblies 350, 450 are positioned on an inner surface of first and second jaw member 312, 314, respectively, e.g., on a tissue contacting surface thereof. Electrode assemblies 350, 450 operate in a manner substantially similar to electrode assemblies 250, 550 described hereinabove. By including electrode assemblies 350, 450 on an inner surface of first and second jaw member 312, 314, respectively, the type of tissue being grasped therebetween may be determined. Such identification of tissue may occur at any time prior to a sealing of the target tissue.

(41) Electrode assemblies 50, 150, 250, 350, 450, 550 may also be used post-sealing to determine if a proper seal has been formed. By measuring the impedance of a post-sealing tissue, and comparing the impedance measurements thereof with known values of properly sealed tissue processing unit 20 (FIG. 2) may alert a user of the condition of the post-sealing tissue. Alternatively, processing unit 20 may compare the post-sealing impedance measurements of the tissue with the pre-sealing impedance measurements thereof to determine if a proper seal has been affected.

(42) Referring now to FIGS. 9-12, another embodiment of the present disclosure is shown generally as endoscopic device 500. Briefly, endoscopic device 500 includes a housing 520 and an elongated tubular member 512 extending from the housing 520. Tubular member 512 defines a plurality of working channels or lumens 515a, 515b, 515c extending therethrough. Proximal end 516 of tubular member 512 mechanically engages or is supported on or by housing 520. Tubular member 512 may be rigid, flexible and/or selectively rigid. Housing 520 may include a steering mechanism 580 for controlling or articulating distal end 514 of tubular member 512 in any suitable manner. Working channels or lumens 515a, 515b, 515c may be configured to receive an endoscope, electrosurgical instrument, snare or the like therethrough.

(43) As seen in FIG. 9, an electrode assembly 650 extends through working channel or lumen 515a of tubular member 512. As seen in FIG. 10, electrode assembly 650 includes a plurality of electrodes 650a mounted about a probe-like base or core member 600. Electrodes 650a may be axially spaced apart from one another along a length of core member 600. Electrode assembly 650 may include a cauterization and/or sealing tip 605 for treating tissue. As seen in FIG. 10, tip 605 may be sharpened, tapered and/or beveled.

(44) Electrode assembly 650 is operably connected to a processing unit 20(see FIG. 9). Processing unit 20 is substantially similar to processing unit 20 described hereinabove and thus will not be described in further detail herein. Additionally, processing unit 20 may include a drive mechanism 25 for advancing and retracting multi-electrode assembly 650 from within channel 515a of tubular member 512.

(45) Alternatively, as seen in FIGS. 11 and 12, base or core member 600 may include a flattened distal end surface 600a. Flattened distal end surface 600a may include multi-electrode assemblies of multiple configurations. As shown in FIG. 11, base member 600 may include a linear array of electrodes 750 provided on distal end surface 600a (e.g., an exemplary four electrodes being shown), or a grid-like or rectangular array of electrodes 850 provided on distal end surface 600a (e.g., an exemplary 44 rectangular array being shown) multi-electrode assembly 850. Electrode arrays 750, 850 operate in a manner similar to the multi-electrode assemblies or arrays described above and thus will not be described in further detail herein.

(46) With reference to FIGS. 13A and 13B, in yet another embodiment, base member 600 defines a sheath 602 that includes a coaxially electrode 950 extending a length thereof. In this manner, only a distal end 950a of electrode 950 is exposed. It is envisioned that distal end 950a of electrode 950 may form a pointed surface for penetrating tissue. Coaxially electrode 950 may be operably connected to a high frequency generator HFG capable of generating a signal between 30 MHz-30 GHz.

(47) While several embodiments of the disclosure have been shown in the drawings, it is not intended that the disclosure be limited thereto, as it is intended that the disclosure be as broad in scope as the art will allow and that the specification be read likewise. Therefore, the above description should not be construed as limiting, but merely as exemplifications of preferred embodiments. Those skilled in the art will envision other modifications within the scope and spirit of the claims appended hereto.