JP2000513970A - Selectively insulated electrodes and methods of using such electrodes in hollow viscous tissue portions filled with physiological fluid - Google Patents

Abstract

SUMMARY OF THE INVENTION The present invention provides a method and apparatus for electrosurgically treating tissue in hollow viscous tissue containing a physiological fluid. According to one example of the above method, a surgical instrument 12 comprising a proximal end, a distal end, and an elongated shaft 16 having an active electrode 14 near the distal end is introduced into hollow viscous tissue to bring the active electrode into a physiologically viscous tissue. Place in fluid. Then, while converging the current generated from the active electrode, the current is caused to flow between the active electrode and the return electrode so that the current flows to a desired region of the tissue.

Description

DETAILED DESCRIPTION OF THE INVENTION Selectively insulated electrodes and methods of using such electrodes in hollow viscous tissue sections filled with physiological fluid Field of the invention The present invention relates generally to the field of electrosurgery, and more particularly to electrosurgery performed in hollow viscous tissue filled or expanded with a liquid. In one example of a particular embodiment, the invention relates to electrosurgery for cauterizing and resecting the endometrium. Background of the Invention Electrosurgery is widely used to treat various diseases of the uterus, such as abnormal uterine bleeding and infertility. Therapeutic procedures include hysterectomy, endometrial ablation, endometrial resection, submucosal fibroid ablation, submucosal fibroid resection, intramural fibroid resection, transmural myoma resection, cervical and cervical duct resection Other therapeutic procedures include nephrectomy (laparoscopy), prostatectomy (cystoscopy), ovariectomy, lung tissue and tumor removal (thoracoscopy), and the like. Of these electrosurgery, those dealing with uterine treatment are of particular interest. Menorrhagia or abnormal uterine bleeding is a frequent clinical problem encountered by gynecologists. A common method of treating such abnormal bleeding is hysterectomy. It is estimated that approximately 650,000 hysterectomies are performed each year in the United States. However, in particular, the development of new techniques and techniques for treating such abnormal bleeding in a relatively invasive manner has made the need for hysterectomy increasingly less desirable. For example, recent developments include employing hysteroscopic surgery using laser or high frequency electrosurgical energy to destroy or remove the endometrium and fibroid parts by direct visualization. Such an approach is effective in substantially reducing menstrual blood outflow and reducing secondary dysmenorrhea. For example, a typical device and method for performing both endometrial ablation and endometrial ablation are described in US Pat. No. 5,456,689, the disclosure of which is incorporated herein by reference. Included as Other exemplary ablation / cauterization devices are U.S. Ser. No. 08 / 322,680 filed on Oct. 13, 1994 (Attorney Docket No. 16944-001100) and co-filed Nov. 8, 1995. No. 60 / 008,225 (Attorney Docket No. 16944-001200), the entire disclosure of which is incorporated herein by reference. Such electrosurgical resection / cauterization devices are typically configured to employ a monopolar current when used in a hollow body cavity, such as the uterus. When using a monopolar current, the cutting or cauterizing surface usually consists of an active electrode and a conductive pad return electrode applied to the patient's skin. Therefore, the current flowing out of the active electrode is dispersed in a low-density current field that ends at the return electrode. The return electrode is large enough to reduce the current density to a level low enough that the skin is not damaged (burned) by the return current. However, even though the current density is small, the cutting current transmitted from the inner wall of the uterus to the return pad may be concentrated in vulnerable tissues such as the intestine, which may be caused by accidental contact with the outside of the uterus. Occur. Another problem with the use of electrosurgery in body cavities, such as the uterus, is that the body cavity must be sufficiently well visualized that the desired tissue can be visualized, and that there is enough room for successful manipulation of the surgical instrument. Is usually needed to be extended. Non-conductive fluids are commonly employed to dilate the uterus. Common non-conductive dilatation fluids include sorbitol, glycine, sorbitol-mannitol, or mannitol. However, such fluids can in some cases pose a danger to the patient. For example, if excessive amounts are absorbed into the patient's circulatory system, it can lead to pulmonary edema. In addition, such fluids are electrolyte-free, and if excessively absorbed, cause plasma dilution of electrolytes such as sodium, potassium, and the like. This can further result in heart disease. Also, such fluids transfer water to brain cells, causing cerebral edema. Finally, glycine is metabolized in the body and decomposed into ammonia. Such toxic substances can cause disturbance of consciousness, coma, or even death. To avoid the danger of such complications, the fluid loss (difference between the used inflation fluid and the fluid recovered from the surgery) is carefully monitored during surgery and the inflation pressure is required for visualization. Control to a minimum. Such an approach is described, for example, in U.S. Patent Application Serial No. 60 / 006,408, filed November 9, 1995, which is incorporated herein by reference (Attorney Docket No. 16944-000710). I have. The use of an electrolyte solution to dilate the uterus is commonly used in electrosurgery because it distributes the radiofrequency current in all directions and reduces the effect of coagulation or cutting at the tissue / electrode interface. I have been forgotten. Specifically, when high frequency current is used in an environment containing a non-conductive fluid, the current supplied to the active electrode is more directly into the tissue in contact with the electrode than the non-conductive fluid. Flows. Thus, the power is distributed throughout the body in a substantially hemispherical pattern. Further, because the current is sent through only a small portion of the active electrode, the current density at the active electrode is sufficient to ablate or coagulate tissue. On the other hand, when the non-conductive fluid is replaced with a conductive fluid, the power supplied to the active electrode is dispersed in a substantially spherical pattern. As a result, the current density at the active electrode is reduced such that effective ablation or coagulation cannot occur. Also, as the tissue coagulates, the impedance of the tissue increases. Therefore, if the surrounding fluid is conductive, little coagulation can occur because the current preferentially flows through the low impedance fluid over the high impedance tissue. Therefore, for these and other reasons, it is desirable to provide systems, methods, and devices that provide a more secure environment when used with electrosurgical techniques, particularly in combination with dilation fluids. Such systems, methods, and devices can reduce or eliminate the aforementioned risks associated with the use of the non-conductive expansion fluid described above. Further, such systems, methods, and devices can further prevent or reduce the possibility of unwanted current increases in the body. Further, in certain aspects, it would be desirable to provide systems, methods, and devices that can perform effective ablation and coagulation in either conductive or non-conductive dilatation fluids. Summary of the Invention The present invention provides systems, methods and devices for enhancing patient safety in electrosurgical procedures. The systems, methods and devices of the present invention are particularly useful in electrosurgery in hollow, viscous organs, such as body cavities or tissues, including fluid-dilated or filled organs, such as the uterus and prostate. . In one embodiment, the present invention provides a method for treating a hollow viscous organ containing a physiological fluid, such as normal saline or lactated Ringer's solution. According to the method of the present invention, a surgical instrument comprising a proximal end, a distal end, and an elongated shaft having an active electrode located near the distal end is inserted into a hollow viscous organ. When inserted into the hollow viscous device, the active electrode is surrounded by a physiological fluid. At this time, an electric current flows between the active electrode and the return electrode, and the electric current concentrates on a desired region of the tissue. In this way, the current flows toward the tissue rather than diffusing into the physiological fluid, which can cut, dry or coagulate the tissue. In one aspect of the invention, the active electrode is at least partially insulated to concentrate current. This insulation of the electrodes is further advantageous in that it reduces the surface area of the electrodes and reduces the maximum power required for ablation. If desired, the active electrode may have a non-circular cross-sectional shape to form a region where current is concentrated. In one example of a particular embodiment, the current is concentrated by introducing a non-conductive fluid to a selected portion of the electrode. In this aspect, selected portions of the electrode surrounded by the non-conductive fluid are insulated, thereby concentrating the current emitted from the electrode. In another example embodiment, the invention comprises an elongated shaft having a proximal end and a distal end. Further, an active electrode is operatively mounted near the tip of the shaft. In addition, the device includes means for concentrating the current emitted from the active electrode, such that the current flows through the physiological fluid and into the tissue in a convergent pattern. In one aspect of the invention, the means for concentrating the current comprises an insulator that at least partially covers the active electrode. In another aspect, the means for concentrating the current is constituted by a certain region of the active electrode formed in a shape for concentrating the current. The means for concentrating the current may be constituted by a combination of an insulator covering at least a part of the active electrode and a region formed on the electrode. In still another embodiment, the insulator is formed of a non-conductive sheath, and the sheath moves on the electrode to selectively insulate a part of the electrode. In another method embodiment, the surgical instrument is introduced into the uterus. The surgical instrument comprises a proximal end and a distal end, an elongated electrode having an active electrode near the distal end, and a return electrode. The active electrode has a constant surface area selected to produce a current density sufficient to ablate or coagulate tissue. Also, an electrically conductive fluid is introduced into the uterus to dilate the uterus. Thereafter, the active electrode is activated and a magnetic field is formed around the active electrode. The active electrode preferably comprises a wire loop having a diameter in the range from about 3mm to about 12mm. If desired, the wire loop may include spurs or "stars" to enhance coagulation. Preferably, the return electrode is arranged at a selected fixed position on the base end side of the active electrode, and deforms into a non-spherical pattern in which the power generated in the active electrode converges, that is, rather than proceeds in a spherical pattern. Move in a direction that tends to converge on or toward the return electrode. In this embodiment, a higher current density occurs in the tissue surrounding the tissue-electrode interface. In a particularly preferred embodiment of the method of the present invention, the conductive fluid comprises an isotonic cleaning fluid. In another aspect of the method, the surgical instrument further comprises a morcellator, which can cut the tissue removed by the active electrode. In yet another aspect, the conductive fluid is preferably introduced into the body cavity through the elongate shaft. The return electrode can be formed in various forms, for example, a pad, a wire coil, the elongated shaft itself, a roller attached to the elongated shaft on the base end side of the active electrode. In this embodiment, current is dispersed from the active electrode through the conductive fluid to a return electrode attached to the surgical instrument. Placing this return electrode in the body cavity is advantageous in that it reduces power dissipation in the conductive fluid and increases the amount of current near the interface between the electrode and tissue. Furthermore, within the body cavity, the return electrode also helps prevent current concentration in the undesired area. In addition, the use of conductive fluids enhances patient safety and comfort by reducing changes in blood electrolyte balance and / or osmolarity. The present invention further provides a system for surgically treating tissue, particularly the interior of the uterus or prostate. The system consists of a surgical instrument having a proximal and distal end, an elongated shaft having an active electrode and a return electrode near the distal end. The system further comprises a conductive fluid, which is introduced into the body cavity and forms a conductive path between the active electrode and the return electrode within the body cavity. . The active electrode has a surface area selected to produce a current density sufficient to ablate or coagulate tissue. Further, the return electrode is arranged at a selected fixed position on the base end side of the active electrode, and is configured to deform into a non-spherical pattern in which the power generated in the active electrode converges. In an example of a preferred embodiment, the conductive fluid comprises an isotonic cleaning fluid. In another aspect, the surgical instrument preferably includes a morcellator for slicing the tissue removed by the active electrode. In yet another embodiment, a bore is provided in the elongate shaft and a suction source is provided for aspiration of the removed tissue through the elongate shaft. Further, in another aspect, the conductive fluid is introduced into the body cavity via an elongate shaft interior. The surgical instrument optionally includes an endoscope, the endoscope being operatively attached to the elongate shaft such that the active electrode can be viewed through the endoscope. Also, if desired, ultrasound can be used to visualize tissue in the body cavity. Preferably, the return electrode is operatively attached to the proximal end of the active electrode on the elongate axis and comprises a wire coil, a pad on the elongate axis, or the elongate axis itself. Preferably, the active electrode comprises a wire loop having a diameter ranging from about 3 mm to about 12 mm. Further, the present invention provides a surgical instrument comprising an elongated shaft having a proximal end and a distal end. An active electrode is operatively mounted near the tip of the shaft. Further, a passive return electrode is operatively mounted at a location on the elongate axis spaced from the active electrode. The active electrode has a surface area selected to produce a current density sufficient to ablate, coagulate or evaporate tissue. Furthermore, the return electrode is arranged at a certain position selected such that the power generated at the active electrode is dissipated to a larger surface area compared to the active electrode. Preferably, the passive return electrode is formed on an elongate axis or is constituted by the elongate axis itself. Preferably, the active electrode comprises a wire loop having a diameter ranging from about 3 mm to about 12 mm. The wire loop may optionally include a spur or "star" that rotates to promote tissue coagulation. In another embodiment, the present invention provides a method for surgically treating a uterus. The method comprises introducing a surgical instrument comprising an elongated shaft having a proximal end and a distal end into the uterus. The surgical instrument further includes an activation electrode disposed near the distal end and having a cutting portion and a coagulation portion or a drying portion. In addition, fluid is introduced into the uterus to dilate the uterus. Thereafter, current flows between the active electrode and the return electrode. To ablate the tissue, a cut of the activation electrode is moved along or through the tissue. Also, the coagulated or dried portion of the active electrode contacts the tissue to coagulate or dry the tissue. In this way, both ablation and coagulation or drying can be performed on the same electrode. For example, the electrode can be pulled through tissue to remove tissue fragments. The electrode can then be coagulated back into the rest of the tissue. Also, in some cases, the tip of the electrode can be used for cutting and the subsequent surface can be used for solidification. In another aspect of the method, the active electrode comprises a wire loop having a diameter in a range from about 3mm to 12mm. The active electrode is at least partially insulated so that the power generated at the active electrode diverges from the non-insulated portion of the active electrode to form a constant convergence pattern. In yet another aspect, the active electrode has a constant cross-section, the cross-section having a major axis and a minor axis, wherein the major axis is longer than the minor axis. In such a configuration, the tissue is cut by the electrode moving in the tissue substantially parallel to the long axis. To coagulate or dry the tissue, the active electrode is placed in the short axis region relative to the tissue. In some cases, the amount of power supplied to the electrode and / or the type of waveform generated at the electrode may change depending on whether cutting or coagulation occurs. For example, a sinusoidal waveform may be used for cutting and an attenuated waveform for coagulation. The active electrode has an elliptical or hexagonal cross section as an example. In another aspect of the invention, the fluid used to dilate the uterus is conductive. Alternatively, the fluid may be non-conductive. Further, in an additional aspect, the elongate shaft can also be used as a return electrode. In this embodiment, both the active and return electrodes are inserted into the uterus. Alternatively, the feedback electrode can be constituted by a diffusive pad. In this embodiment, the diffusible pad is placed on the patient's skin outside the uterus. The present invention further provides another embodiment of a method for surgically treating a uterus. According to this method, a surgical instrument consisting of an elongated shaft having a proximal end and a distal end and an active electrode near the distal end is inserted into the uterus. In addition, conductive or non-conductive fluid is introduced into the uterus to an extent sufficient to dilate the uterus. Thereafter, current is passed between the active electrode and the return electrode, causing the active electrode to move along or through the tissue. At least a portion of the active electrode is insulated, so that the power generated at the active electrode is formed into a constant convergence pattern to ablate the tissue. In another aspect of the method, the active electrode comprises a wire loop having a diameter in a range from about 3mm to 12mm. In yet another aspect, the insulator covers about 10% to about 90% of the active electrode. In another aspect, the active electrode has a cross-sectional shape having a major axis and a minor axis, and the major axis is equal to or longer than the minor axis. When cutting tissue, the cut portion moves in the tissue substantially parallel to the long axis. When the tissue is coagulated or dried, the coagulated part or the dried part comes into contact with the tissue. As a result, both ablation and coagulation or drying can be performed with the same electrode. In yet another embodiment, the invention provides a surgical instrument comprising an elongated shaft having a proximal end and a distal end. Further, an active electrode is operatively mounted near the tip of the elongated shaft. The active electrode has a high current density region for ablating the tissue as it moves along or within the tissue. The active electrode also has a relatively low current density region for coagulating or drying the tissue when in contact with the tissue. In yet another aspect of the present invention, the active electrode is at least partially insulated, and the power generated at the active electrode diverges from the non-insulated portion of the active electrode to form a concentrated pattern. It is configured as follows. In another aspect, the active electrode comprises a wire loop having a diameter in a range from about 3 mm to about 12 mm. Further, in another aspect, the active electrode has a cross-sectional shape having a major axis and a minor axis, and the major axis is longer than the minor axis. The high current density region is located near the long axis, and the low current density region is located near the short axis. Preferably, the cross-sectional shape of the active electrode is elliptical or hexagonal. Further, in another aspect, the device further comprises a return electrode. In one embodiment, the return electrode is a diffusive pad that is placed outside the patient. Alternatively, the elongate shaft can be used as the return electrode. In yet another embodiment of the present invention, there is provided a surgical instrument comprising an elongated shaft having a proximal end and a distal end. An active electrode is operatively mounted near the tip of the elongated shaft. At least a portion of the active electrode is insulated so that the power generated at the active electrode forms a constant divergence pattern. In one embodiment, the device includes an insulator covering about 10% to about 90% of the active electrode. In yet another aspect, the active electrode comprises a wire loop having a diameter ranging from about 3 mm to about 12 mm. In yet another aspect, the active electrode of the device coagulates the tissue when placed in contact with the tissue with a high current density region for ablating the tissue when moving along or through the tissue. Or it has a relatively low current density region for drying. BRIEF DESCRIPTION OF THE FIGURES FIG. 1 illustrates an example of a system suitable for performing electrosurgical treatment of tissue in an environment having a conductive fluid according to the present invention. FIG. 2 is a side view of one example of an electrosurgical device suitable for the system of FIG. FIG. 3 is a side view of a main body portion of the device in FIG. 2 from which a sheath portion is removed. FIG. 4 is a side view of the sheath of the device of FIG. FIG. 5 is a side view of the handle portion of the device of FIG. FIG. 6 is a diagram illustrating an alternative embodiment of the apparatus of FIG. 2 having a coil as a return electrode according to the present invention. FIG. 7 illustrates an alternative embodiment of the morcellation shaft of the device of FIG. 2 having a return electrode pad on the upper side in accordance with the present invention. FIG. 8 illustrates a roller ball having an active electrode and a return electrode usable in a non-conductive fluid according to the present invention. FIG. 9 illustrates the device of FIG. 2 used in electrosurgical treatment of a uterus dilated with a conductive fluid in accordance with the present invention. 10A to 10C are three schematic cross-sectional views of an alternative active electrode configuration. FIG. 11 is a perspective view of a particularly preferred active electrode according to the present invention. FIG. 12A is a cross-sectional view of the active electrode of FIG. 12B and FIG. 12C are diagrams showing a cross-sectional form of an electrode different from FIG. 12A. FIG. 13A is a top view of an alternative active electrode according to the present invention. FIG. 13B is a cross-sectional view of the electrode taken along a line BB in FIG. 13A. FIG. 13C is a side view of the electrode of FIG. 13A. FIG. 14A is a top view of another alternative active electrode configuration according to the present invention. FIG. 14B is a cross-sectional view of the electrode taken along a line BB in FIG. 14A. FIG. 14C is a side view of the electrode of FIG. 14A. FIG. 15A is a top view illustrating a further alternative active electrode configuration according to the present invention. FIG. 15B is a cross-sectional view of the electrode taken along a line BB in FIG. 15A. FIG. 15C is a side view of the electrode of FIG. 15A. 16A-16C are top views illustrating alternative electrode configurations having a movable non-conductive sheath. FIG. 17 is a top view showing the configuration of another alternative electrode having a non-conductive sheath and a bore for guiding a non-conductive fluid to a portion of the electrode. 18A and 18B are top views illustrating yet another alternative electrode configuration having a non-conductive deployable sheath that passes a non-conductive fluid over a portion of the electrode. FIG. 19 is a top view illustrating yet another alternative electrode configuration having a visualization device around which a plurality of holes for transferring a non-conductive fluid to a portion of the electrode are provided. FIG. 20 is a top view illustrating yet another alternative electrode configuration having a visualization device and an outer tube that transfers a non-conductive fluid to a portion of the electrode. Detailed description of specific embodiments The present invention provides methods, systems and devices for electrosurgical treatment of tissue. These methods, systems and devices are preferably used to treat tissue in a body cavity or organ that has been filled or expanded with an inflation fluid. Although useful in a variety of body cavities or organs, the present invention has the greatest utility in endosurgical electrosurgical treatment, including urology, heart disease, radiology, gynecology, laparoscopy, etc. The present invention can be usefully used in the field. The expansion medium is preferably composed of a conductive fluid such as a saline solution, Ringer's lactate solution, etc., which does not significantly change the electrolyte balance in blood. In such an embodiment, the risk of cerebral edema and other risks that may occur if the expansion medium enters the bloodstream can be significantly reduced or eliminated. However, in some cases, it may be possible to use a non-conductive fluid. In one preferred embodiment, the device according to the present invention has an active electrode, such as an electrosurgical cutting wire or loop, and is described in U.S. Patent Application Ser. No. 60 / 008,225, referenced above. It is possible to have a cutting spur or a cutting star. Furthermore, the device according to the invention has a "passive" return electrode that can be mounted on an electrosurgical instrument, which itself can also be present in a body cavity. Preferably, the return electrode has a surface area substantially greater than the surface area of the active electrode such that the current density level at the return electrode is substantially smaller than the (current density level) at the active electrode. Further, the return electrode is preferably arranged at a predetermined position on the base end side of the active electrode. With such an arrangement, the power generated from the active electrode is dispersed in a constant pattern, and the dispersed power is Rather than traveling in a spherical pattern, it propagates in a direction toward the return electrode. In this way, a very concentrated current is generated at the interface between the active electrode and the tissue, allowing cutting and cauterization at the active electrode. High current density at the electrode-tissue interface can also be obtained by reducing the size of the active electrode. Preferably, the active electrode comprises a wire loop having a diameter of about 3 mm to about 12 mm. The current that diffuses into the conductive extension liquid collects at the return electrode. By increasing the surface area of the return electrode, the return current will have a sufficiently low current density and will not cut, coagulate, or otherwise harm tissue within the body cavity. The present invention also provides systems and methods for treating viscous organs such as cavities and torso containing physiological fluids. According to the present invention, an instrument comprising an elongated shaft having a proximal end and a distal end is inserted into a viscous organ. The active electrode located near the tip is surrounded by a physiological fluid within the viscous organ. The current flows between the active electrode and the return electrode while converging the current from the active electrode toward the tissue in a constant focusing pattern. The active electrode can be at least partially insulated to concentrate the current in the desired area. In this way, the non-insulating portion of the active electrode can be directed to concentrate the current on a desired region. In addition, the isolation reduces the maximum power required for ablation. The active electrode may have a non-circular cross-sectional shape. In this way, current concentrates on the electrode area used for cutting and coagulating tissue. The active electrode may have a combination of an insulating portion and a non-circular cross-sectional shape to concentrate current. A specific device 10 for treating electrosurgical tissue will now be described with reference to FIG. Apparatus 10 has a surgical instrument 12 for electrosurgically treating tissue, and is described in further detail below. Briefly, surgical instrument 12 has an active electrical species 14 that can be used for cutting and / or cauterizing tissue, and a morcellator shaft 16 having a morcellator 18 spaced from active electrode 14. The drive unit 20 is provided for rotating the morcellator shaft 16. The drive unit 20 includes various control devices including a drive cable output 22 for connection to a drive cable 24, a direction control switch 26, a start / stop switch 28, an LED readout switch 30, and a speed control switch 32. The device 10 further includes an electrosurgical generator (ESU) 34 that supplies high frequency current to the active electrode 14. The ESU 34 has a start switch 36 and a power control switch 38. Current is supplied to active electrode 14 via line 40, while line 42 provides a return path to ESU 34. Referring now to FIGS. 2 and 3, the structure of surgical instrument 12 will be described in further detail. As previously described, surgical instrument 12 has an active electrode and a morcellator shaft 16. The active electrode 14 is formed in the form of a wire loop that is electrically connected to the wire 40 (see FIG. 1). Wire loops can be rotated to enhance the effect of coagulation when insulated, as described in co-pending application Ser. No. 60 / 008,225, such as posts, stars, cylinders and the like. May be provided as needed. Preferably, electrode 14 has a diameter in the range of about 3 mm to about 12 mm. The morcellator shaft 16 has a lumen extending therethrough so that tissue removed by the morcellator 18 can be suctioned from the lumen. The surgical instrument 12 also has a handle 44 that is easily grasped by the surgeon. The sheath 46, which is preferably non-conductive, provides a protective cover for the morcellator shaft 16. The morcellator shaft 16 is attached to a resector body 48 having a thumb ring 50. The thumb ring 50 and the handle 44 cooperate to move the active electrode 14 in the axial direction. More specifically, a return spring 52 is disposed between the handle 44 and the thumb ring 50 to urge the thumb ring 50 away from the handle 44. As the surgeon pushes thumb ring 50 toward the handle, active electrode 14 moves forward. As the surgeon relaxes his hand, the thumb ring 50 is slowly released from the handle 44 by a return spring that slowly returns the active electrode 14 toward the handle 44. A telescope 54 is preferably provided so that the active electrode can be seen during surgery. As best shown in FIG. 5, the handle 44 has a scope base 56 that holds a telescope 54. An ultrasonic transducer is optionally used along with telescope 54 (and optionally in place of telescope 54) to expose tissue within the body cavity. The use of ultrasound is described in co-pending application Ser. No. 08 / 322,680, previously incorporated by reference. As shown in FIG. 2, an optical cable is provided so that the body cavity can be illuminated, and the light source is connected to the telescope 54. As shown in FIG. 3, the surgical instrument 12 uses a morcellator shaft 16 as a return electrode. The power generated at the tip of the electrode 14 by extending the electrode from the shaft 16 is dispersed outwardly into the uterine tissue in a converged non-spherical pattern. As indicated by phantom lines, the current flowing from the proximal portion of the active electrode passes through the conductive medium in a substantially direct line concentrated throughout the morcellator shaft 16. As described above, when the amount of power dispersed in the conductive irrigation solution is reduced and the electrode 14 is moved proximally in the tissue, the proximal portion in contact with the tissue cuts or coagulates the tissue. To have a sufficient current density. Due to the large surface area of the morcellator shaft 16, the current density of the morcellator shaft 16 is at a safe level such that contact of the morcellator shaft 16 with tissue does not damage the tissue. The morcellator shaft 16 is made of a conductive material such as stainless steel, and is electrically connected to the return line 42 (see FIG. 1). Surgical instrument 12 can also be configured such that sheath 46 functions as a passive return electrode. However, the sheath 46 is preferably non-conductive to maximize patient safety. As best shown in FIGS. 2 and 4, the surgical instrument 12 has an irrigation connector 58 for introducing a conductive medium into a body cavity. By using the inflow valve 60, the amount of fluid flowing into the body cavity can be controlled. When the body cavity is sufficiently inflated, the inflow valve 60 is closed to maintain the fluid pressure in the body cavity. As shown in FIG. 2, since the liquid tube 62 is provided on the surgical instrument 12 and communicates through a liquid to an inner hole portion provided in the morcellator shaft 16, the minced tissue is removed from the body cavity. Can be sucked from. Further, a cock valve having a handle 65 is provided to prevent fluid flow through the tube 62. Referring now to FIG. 6, another embodiment of the surgical instrument will be described. Surgical instrument 64 is essentially the same as the surgical instrument of FIG. 2 except for the configuration of the passive return electrode. More specifically, the surgical instrument 64 has a return electrode 66 configured in the form of a wire coil. The return electrode 66 is held in a non-conductive housing that attaches to the utensil opposite the cleaning connector 58. The feedback line 42 is connected to the feedback electrode 66 to complete an electric circuit. With this configuration, the current from the active electrode flows to the return electrode 66 via the conductive body in the sheath. Referring to FIG. 7, another embodiment of the morcellator shaft 70 for use with the surgical instrument 12 is described. The molcerator shaft 70 differs from the molcerator shaft 16 of FIG. 3 only in that the shaft 70 has a dispersion pad 72 attached to the shaft near the active electrode 14; Are the same. Preferably, pad 72 is located within about 5 mm to about 50 mm of electrode 14. The feedback line 42 is electrically connected to the distribution pad 72, and the distribution pad 72 can function as a passive feedback electrode. In this way, the current flowing from the active electrode is dispersed through the conductive medium and collects at the distribution pad 72 at a sufficiently low current density to provide a safe working environment. Further, the distance between the pad 72 and the electrode 14 is selected such that forces dispersed in the conductive inflation fluid are concentrated on the pad 72 to form a convergent aspheric dispersion pattern. Thus, a high level current is supplied to the tissue / electrode. Another embodiment of the active electrode 74 will be described with reference to FIG. The active electrode 74 is configured in contact with a roller 76, which also has a return electrode 78. The electrode 74 and the electrode 78 are separated by an insulating spacer. The surface areas of the active electrode 74 and the return electrode 78 are substantially equal, and the current densities of both the active electrode 74 and the return electrode 78 are substantially the same. To treat the tissue, the roller 76 is rotated along the tissue to ablate the tissue where the electrodes 74 and 78 contact. Roller 76 is preferably used in a non-conductive expansion medium. Roller 76 is suitably mounted on a shaft (not shown) and can provide a source of irrigation and aspiration similar to that previously described with respect to surgical instrument 12. Another electrosurgical device used with conductive media includes a pair of proximal needle electrodes. Such devices operate in a bipolar fashion, with current flowing between the two needles. A ball can optionally be provided on each of the needles to adjust the depth of the needle in the tissue. Referring now to FIG. 9, a specific method for performing resection / cauterization of the endometrium using the surgical instrument 11 will be described. First, the sheath 46 is introduced into the uterus U via the cervix C with a crater (not shown). Next, the obturator is removed, and the morcellator shaft 16 is passed through the sheath 46 until the active electrode 14 and the molcer 18 are exposed in the uterus U. Next, the inflow valve 60 is opened, and the conductive cleaning fluid is supplied from the cleaning connector 58. The inflation liquid is filled into the uterus U until the uterus U is sufficiently expanded. Next, a current is supplied to the active electrode 14, and thereafter, the handle 44 and the thumb ring 50 are operated to move the active electrode 14 as described above. The active electrode 14 is moved along and through the tissue to remove and / or cauterize the endometrial surface. All excised tissue is cut into small pieces with a morcellator 18. Also, the small pieces are removed through the tube 62 through the morcellator shaft 16. Once fluid has been withdrawn from tube 62, new fluid is infused so that uterus U maintains its expanded configuration. To monitor the fluid volume in the uterus U, a flow device as described in U.S. Patent Application Serial No. 60 / 006,408, previously incorporated by reference, may be used. If the uterus is expanded with a conductive fluid, the body can absorb the conductive fluid more safely, and a safer working environment can be obtained. In addition, by using the morcellator shaft 16 as a return electrode, the current flowing from the active electrode 14 is dispersed by the conductive fluid, and as a route to the dispersed electrode disposed on the cortical layer, a surrounding organ or tissue such as the intestine is used. A superb operating environment is provided to the uterus to gather on the shaft 16 rather than spread. If the shaft 16 inadvertently contacts tissue, the current density is low enough that it does not damage such tissue. In addition, by using an active electrode with a relatively small surface area and a return electrode close to the active electrode, a high level of current is generated at the active electrode, thereby effectively removing the rough sheath surrounded by the conductive medium. It can be excised and / or coagulated. Another active electrode focuses the current in a conductive or non-conductive physiological fluid such that the electrode has electrosurgical function. The electrodes are configured to allow ablation or coagulation of the tissue based on the orientation of the electrode relative to the tissue or based on a set power and / or type of power waveform. The electrodes are divided into a high current density region used to ablate tissue and a low current density region used to coagulate tissue so that ablation and coagulation procedures can be performed using the same electrode. Is formed. Excision is performed when the high current density region contacts the tissue, and coagulation is performed when the low current density region contacts the tissue. By controlling the amount of insulator provided on the electrode and / or by changing the shape of the electrode, the active electrode can have both high and low current density regions. 10A to 10C are conceptual diagrams showing the configuration of an electrode for focusing a current. FIG. 10A is a conceptual diagram illustrating a cylindrical wire 102 or a simple active electrode 100 that includes a conductive portion 110 and a non-conductive portion 112. Non-conductive portion 112 has a larger area than conductive portion 110 such that exposed surface portion 106 has an area less than half the total surface area of wire 102. By using a non-conductive portion, current flows through only the exposed surface 106 of the conductive portion 110. In this way, rather than diffusing into the fluid in the cavity or sinus, the function of the electrosurgery is used to focus the current so that it passes through the tissue. In addition, reducing the surface area of the electrode, ie, the area of the exposed surface 106, can increase the current density, thereby reducing the maximum power required to treat tissue ablation or coagulation. . FIGS. 10B and 10C are schematic diagrams showing the active electrode 100 of FIG. 10A flattened by 25% and 50%, respectively. FIGS. 10B and 10C are diagrams showing the use of insulation and electrode shapes to control the discharge pattern. When the wire 102 is flattened, a cross section in which the major axis is longer than the minor axis is formed. When the active electrode is flattened, the current is concentrated at both ends of the long axis, and the current concentration is controlled by the degree of flatness. With such an arrangement, body tissue can be ablated by moving the electrode along or through the tissue, generally in a direction parallel to the long axis where the cross-sectional current density is greatest. Coagulation or drying of body tissue can be performed by moving the active electrode in a direction parallel to the long axis of the cross section while bringing the tissue into contact with the low current density region of the electrode. In this manner, when a portion of the exposed surface region 106 with low current density contacts body tissue, coagulation or drying can occur without ablation of the tissue. As a result, the same active electrode can be used to ablate or dry body tissue, depending on which portion of the exposed surface area 106 contacts the tissue. Further, it is possible to adjust the electrosurgical function by changing the amount of power supplied to the electrodes and / or the type of waveform. FIG. 11 is a diagram illustrating a preferred embodiment of an active electrode that can be used in any of the devices described herein. The active electrode 120 preferably has a diameter of about 0.5 mm. 005 inches to about 0. A 100-inch round wire 122 is provided. The active electrode 120 has a loop portion 123 partially insulated by an insulating material 124. Insulation 124 preferably covers about 10% to about 90% of the total wire surface. Since the loop portion 123 is only partially insulated, the surface 126 of the active electrode 120 is exposed. The exposed surface 126 of the loop 123 is used for ablation, coagulation and / or desiccation, as described below. FIG. 12A is a side sectional view of the active electrode 120. As current passes through wire 122, current is released from exposed surface 126. Because the wires are selectively insulated, the current flowing out of the exposed surface 126 is concentrated or directed at the tissue to be ablated. In this manner, the electrodes 120 can be used in conductive media while focusing current on tissue rather than dissipating current into the media. The exposed surface 126 can be ablated simply by moving it along or through tissue. In addition, selective insulation can also reduce the peak power required for the ablation process due to the reduced surface area of the wire. In the case of an application that requires coagulation or drying of the tissue, the amount of current flowing through the electrode 120 can be reduced. That is, the body tissue can be agglomerated or dried by lowering the power and bringing the exposed surface 126 into contact with the body tissue. FIGS. 12B and 12C show the electrode 120 with 25% and 50% planarization, respectively. The active electrode 120 can be flattened at another ratio (%). When the active electrode 120 is flattened, a long axis and a short axis are formed. In such an arrangement, the current tends to concentrate near both ends of the long axis. Thus, the exposed surface 126 will have both cuts and solidified or dried sections. Since the current density is greatest at both ends of the major axis, the electrode 120 is moved along or through tissue substantially parallel to the major axis. Further, the electrode 120 is used for coagulating or drying the tissue simply by applying the low current region of the electrode 120 to the tissue and moving the electrode substantially parallel to the long axis. 13A through 13C show another electrode configuration 130 that can be used with any of the devices described herein. That is, the electrode 130 includes a pair of shaped fingers 132 and 134 that enable the electrode 130 to operate in a bipolar manner. As shown in FIG. 13B, the finger portions 132 and 134 are formed and are insulated by an insulator 136 to converge the current in a manner similar to the electrode configuration already described herein. preferable. In this manner, electrode 130 can be used for both physiological and non-conductive fluids. By further shaping and insulating the electrodes, the electrodes 130 can be used for both cutting and coagulating body tissue, as already described in the alternative embodiments above. Thus, the finger portions 132 and 134 can be shaped and selectively insulated in a manner similar to that described in the alternative embodiments above. A particular advantage of using the electrode configuration 130 is that the use of multiple fingers increases the number of cutting edges, thereby increasing the effective cutting or drying surface area of the electrode. It is. As in the embodiments described above, the exposed surface area of finger portions 132 and 134 can be adjusted to adjust the current density at the electrode surface. Alternatively, finger 132 and finger portion 134 can be electrically connected and act as a single electrode. In this case, the fingers 132 and 134 can be used in connection with the distribution pad or other return electrode as described in the above embodiment. Although two fingers are shown in the figure, additional fingers may be provided to further increase the number of cutting or drying ends. For example, in FIGS. 14A to 14C, the electrode configuration 140 includes four finger portions 142, 144, 146 and a finger portion 148. However, the number of fingers can be virtually any, depending on the particular application and the required surface area. As in the embodiment of FIG. 13, the finger portions of the electrode arrangement 140 may be shaped into a predetermined shape to focus current, as described above, and / or selectively insulated by an insulator 149. preferable. 15A-15C illustrate another electrode 150 that can be used with any of the surgical instruments described herein. The electrode 150 is configured to work in a bipolar manner in either a physiological fluid or a non-conductive fluid. The electrode 150 has a U-shaped tip 152, which is separated by an insulator 154. That is, in this embodiment, half of the electrode 150 acts as an active electrode and the other half acts as a return electrode. Also, as shown in FIG. 15B, the electrode 150 is preferably selectively insulated by an insulator 156, as in the previous embodiment, to focus the current to enhance the electrosurgical function. In any of the embodiments shown in FIGS. 13 to 15, a stiffening bridge may be placed between some or all of the fingers. By doing so, the bridge increases the physical integrity of the electrode. The bridge may or may not be electrically insulated. In such an aspect, the location and material of the electrical hooking and fridge allows this embodiment to operate in the previously described monopolar, focused monopolar or bipolar modes. 16A-16C illustrate yet another embodiment of an electrode 160 that can be used with any of the surgical devices described herein and that is particularly useful in hollow viscous tissue filled with a conductive medium. FIG. The electrode 160 includes a movable non-conductive sheath 162 that can move around the electrode 160 to selectively change the exposed portion of the electrode 160. In this aspect, the user can selectively insulate the electrode 160 by simply moving the sheath 162 in the distal direction as shown in FIGS. 16B and 16C. That is, by changing the exposed surface area of the electrode 160, the current can be converged as described above to enhance the electrosurgical function. The sheath 162 is preferably configured to be able to move onto the electrode 160 from outside the patient. With such a configuration, the user can change the exposed area of the electrode 160 at any time while performing a certain treatment. Non-conductive materials that can be used for the sheath portion 162 include a thermoplastic substance, a thermosetting substance, and siloxane. FIG. 17 illustrates another embodiment of an electrode 164 that includes a deployable sheath 166 useful in a conductive medium, similar to the sheath 162 of the electrode 160 as described above. The electrode 164 further includes a central hole and a plurality of openings 168 through which a non-conductive fluid, such as glycine, can be introduced as indicated by arrow 170. Thus, the sheath 166 can be used to adjust the surface area of the electrode 164, as described above, and non-conductive fluid can be introduced only to selected portions of the electrode 164. This non-conductive fluid has a selective insulating action to converge the current and enhance the electrosurgical function in a manner similar to that described above. 18A and 18B show yet another embodiment of the electrode 172, which comprises a deployable non-conductive sheath 174 similar to the sheath in the previous embodiment. Further, the sheath portion 174 includes at least one lumen, as indicated by arrow 176, through which non-conductive liquid can pass when introduced into a portion of the electrode. In such an embodiment, the sheath portion 174 is used to change the exposed area of the active electrode and introduce a non-conductive fluid into a portion of the electrode 172 to focus the current and enhance electrosurgical function. Also used for things. FIG. 19 is a diagram illustrating yet another embodiment of an electrode 178 having a vision system 180. Preferably, the vision system 180 comprises an elongate scope, allowing the user to view the electrodes 178 from outside the patient while performing the procedure. At least one lumen is provided near the viewing system 180 (ie, around the viewing system). The lumen passes through such that a non-conductive fluid is introduced into at least a portion of the electrode 178, as indicated by arrow 179. Therefore, the electrodes 178 are selectively insulated, as described above, to converge the current. As shown in FIG. 20, electrode 178 can be modified to include an outer tube 182 that supplies a non-conductive fluid to electrode 178 as shown by arrow 179. As described above, embodiments configured to supply a non-conductive liquid to the active electrode preferably further include a pump, compressor, tank, etc. for supplying the surgeon with pressurized fluid. Also, a solenoid valve or other actuator may be provided to control the painting of the non-conductive fluid pressurized so that the non-conductive fluid can be dispersed on the electrodes. That is, the solenoid valve is connected to a generator for electrosurgery so that when power is supplied to the electrode, a non-conductive fluid can be supplied to the electrode by driving the solenoid valve. Although the present invention has been described in detail, it should be understood that certain modifications or changes are possible. That is, the scope and spirit of the present invention are not limited to the above description, but are defined by the following claims.

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Claims (1)

[Claims]   1. A method for treating hollow viscous tissue containing physiological fluid,   An outer shaft comprising a proximal end, a distal end, and an elongated shaft having an active electrode near the distal end. Surgical instruments are introduced into hollow viscous tissue with the active electrode surrounded by physiological fluid The process of   To pass the current between the active electrode and the return electrode while converging the current from the active electrode Passing the current through a desired area of the tissue. Law.   2. And moving the electrode around and within the tissue. At least a part of the active electrode is insulated, and the power generated at the active electrode is constant. The method of claim 1, wherein the tissue is ablated by being dispersed in a convergent pattern. .   3. The active electrode has a non-circular cross-sectional shape for converging current, The active electrode is geometrically elliptical, and the active electrode is 2. The method according to claim 1, comprising a drying portion.   4. A method of surgically treating the uterus,   Excised and coagulated or dry at proximal and distal ends and near the distal end Introduces into the uterus a surgical instrument consisting of an elongated shaft with an active electrode comprising Process and   Introducing fluid into the uterus with sufficient fluid to allow the uterus to dilate;   Passing a current between the active electrode and the return electrode;   The tissue is removed by moving the ablated portion of the active electrode around or within the tissue. Excision and assembly by contacting the coagulated or dry portion of the active electrode with tissue Coagulating or drying the fabric.   5. The active electrode comprises a wire loop and is at least partially isolated. By being green, the power generated at the active electrode is dispersed in a constant convergence pattern The method according to claim 4, wherein   6. The active electrode has a cross section including a major axis and a minor axis, the major axis is longer than the minor axis, and the tissue The step of moving the cut portion in moves the active electrode substantially parallel to the long axis. The step of contacting the tissue with the coagulation part or the drying part moves the active electrode near its short axis. A method as claimed in claim 2 or claim 4 comprising contacting the tissue by the side. Law.   7. A method for treating hollow viscous tissue containing physiological fluid,   Surgical hand comprising an elongated shaft having a proximal end, a distal end and an active electrode near the distal end Introducing a surgical instrument into hollow viscous tissue with the active electrode surrounded by physiological fluid About   A non-conductive fluid flows into a part of the active electrode while an electric current flows between the active electrode and the return electrode. Passing the flow and converging the current such that the current passes through a desired area of tissue A method comprising:   8. An elongated shaft having a proximal end and a distal end;   An active electrode operatively mounted near the tip,   The power from the active electrode is converged and the current is applied to physiological fluid and And means for flowing into tissue.   9. The means for converging the current is constituted by an insulating part, and the insulating part is Cover at least a portion of the active electrode or a certain area of the electrode formed for current concentration. The surgical instrument according to claim 8, which is overturned.   10. An elongated shaft having a proximal end and a distal end;   An active electrode operably mounted near the tip. High current density areas that ablate tissue as it moves around or within tissue Consists of a low current density region that coagulates or dries the tissue upon contact Surgical instruments.   11. The active electrode is constituted by a wire loop, and the wire loop is , So that the power generated at the active electrode is dispersed in a constant power convergence pattern. Are also partially insulated and located further outside the patient or outside the elongate axis. The surgical instrument according to claim 10, wherein the surgical instrument comprises a dispersive pad.   12. The active electrode has a cross section including a major axis and a minor axis, the major axis being longer than the minor axis, A current density region exists near the long axis and a low current density region exists near the short axis. The surgical instrument according to claim 1.   13. An elongated shaft having a proximal end and a distal end;   An active electrode operatively mounted near the tip of the shaft,   Since at least a part of the active electrode is insulated, the Surgical apparatus characterized in that the power to be turned is a constant converged power distribution pattern. Utensils.   14． The insulation comprises between about 10 percent and about 90 percent of the active electrode. 14. The method according to claim 13, wherein the active electrode comprises a wire loop. On-board equipment.   15. The active electrode has a cross section including a major axis and a minor axis, and the major axis is at least a minor axis. Equal length, ablation of tissue as active electrode moves around or within tissue High current density areas and low current density areas that coagulate or dry tissue when in contact with tissue 14. The surgical instrument of claim 13, wherein the surgical instrument comprises a zone.   16. An elongated shaft having a proximal end and a distal end;   An active electrode operatively mounted near the tip of the shaft;   Providing a flow of at least one non-conductive fluid to a portion of the active electrode; The current from the physiological fluid in a constant convergence pattern And a fluid supply mechanism configured to flow into tissue Appliances.   17． Further, a non-conductive sheath portion slidably supported on the active electrode is provided. And selectively covering the electrode by covering a certain portion of the electrode with the sheath. 17. The surgical instrument of claim 16, wherein the surgical instrument is insulated.   18. A method of surgically treating the uterus,   From the elongated shaft with the proximal, distal, active and return electrodes near the distal end Introducing a surgical instrument into the uterus, comprising:   The uterus is dilated so as to form a conductive pathway between the active and return electrodes. Introducing a conductive fluid into the   Contacting the active electrode with tissue inside the uterus;   The surface area of the active electrode will generate enough current density to ablate or coagulate tissue. Active electrode and return electrode while the active electrode is in contact with the tissue Flowing a current between   The tissue is excised and coagulated by moving the active electrode around and within the tissue. Solidifying or evaporating.   19. A wire wherein the active electrode has a diameter ranging from about 3 mm to about 12 mm The return electrode is located at a certain position on the proximal side with respect to the active electrode. And the power generated by the active electrode is a constant convergent non-spherical power dispersion pattern. 20. The method of claim 18, wherein the method is configured to perform   20. An isotonic wash in which the conductive fluid is introduced into the uterus via the elongate shaft The surgical instrument is provided with a morcellator; Step of minced tissue resected by the active electrode, Aspirating through said elongated shaft.   21. The return electrode can act on the proximal side of the elongate axis with respect to the active electrode Consists of an electrode pad, wire coil or elongated shaft attached to 19. The method of claim 18, wherein   22. A method of surgically treating internal tissue,   From the elongated shaft with the proximal, distal, active and return electrodes near the distal end Introducing a surgical instrument comprising:   Introduce a conductive fluid into the body tissue to create a current path between the active and return electrodes. Forming,   Contacting the active electrode with tissue within the body tissue;   Current density at which the surface area of the active electrode can ablate, coagulate or evaporate tissue When the active electrode is in contact with tissue, it is selected to be sized to produce Flowing a current between the active electrode and the return electrode while the   The tissue is excised and coagulated by moving the active electrode around and within the tissue. Solidifying or evaporating.   23. An elongated shaft having a proximal end and a distal end;   An active electrode operatively mounted near the tip of the shaft;   Passive return electrode operatively mounted at a fixed position on the shaft spaced from the active electrode Consisting of   Excision and coagulation of tissue when the surface area of the active electrode is in a conductive cleaning fluid Or it is selected to produce a current density sufficient to evaporate, The pole is located proximal to the active electrode and the power generated at the active electrode is Surgical instrument configured to have a converged non-spherical power distribution pattern Utensils.   24. The active electrode has an active surface and the passive electrode has a passive surface And the surface area of the active surface is smaller than that of the passive surface. 24. The surgical procedure according to claim 23, wherein an entirely higher power density occurs at the active surface. Appliances.   25. The passive return electrode is formed on the elongated axis, and the active electrode is Consisting of a wire loop having a diameter ranging from about 3 mm to about 12 mm 24. The device of claim 23, wherein said conductive fluid is an isotonic cleaning fluid.   26. The surgical instrument further dissects tissue removed by the active electrode And a tube hole is provided in the elongated shaft so that A conductive fluid can be introduced into the cavity, and further, through an elongated shaft A suction source for aspirating the removed tissue and operatively attached to the elongated shaft And a telescope, wherein said active electrode is visible by said telescope. 24. The surgical instrument according to 23.