Grooved Slider Electrode for a Resectoscope

1. Field of the Invention

The invention relates generally to an electrode having a slider element adapted for use with an endoscope for tissue ablation and more particularly relates to an electrode having a grooved slider for use in performing procedures, such as, for example, in the genitourinary tract on soft tissue, including bladder and prostrate, for hemostasis, incision, excision and ablation or in performing gynecological procedures such as endometrial ablation.

2. Description of the Prior Art

Use of resectoscopes to treat tissue in the genitourinary tract is well known. Typical of such resectoscopes are the devices disclosed in U.S. Pat. Nos. 5,151,101 and 4,955,884.

Resectoscopes used for transurethral resection of the prostrate (TURP) have four elements, a resectoscope sheath, sometimes referred to as a sheath or an outer sheath, a working element, an electrode and a telescope. The electrodes are operatively connected to a working element and a telescope is slideably inserted through the working element and into position along side of the electrode. Certain electrodes include an electrode stabilizer which is adapted to receive the telescope. The so assembled working element, telescope and electrode are removeably inserted into the sheath to perform a procedure.

In a typical urological procedure, the outer sheath, having an obturator and telescope inserted therein, is visually passed through the urethra to the vicinity of the prostrate and/or bladder neck. The electrode, which is also known as a resectoscope electrode, is typically in the form of a cutting loop located at the distal end of an electrode lead member.

An electrosurgical current, which may be either a coagulation current, a cutting current or some blend thereof is applied to the cutting loop. The energized cutting loop is moved across and cuts the tissue being treated. The cutting loop can also be used to coagulate the wound. In urological procedures, the peak voltage of the electrosurgical cutting currents are typically in the range of 225 volts to about 250 volts at a power level of between about 120 watts to about 200 watts.

A resectoscope electrode having a stabilized cutting loop for a resectoscope is described in U.S. Pat. 4,917,082.

The resectoscope electrode described in U.S. Pat. 4,917,082 is adapted for use with a urological endoscope or resectoscope. The electrode comprises an electrode lead, an electrode end and an electrode stabilizer. U.S. Pat. 4,917,082 discloses that the electrode may take the form of a coagulating electrode, knife electrode, retrograde knife electrode, punctate electrode or roller electrode having a smooth exterior surface.

Continuous flow resectoscopes which utilize a cutting loop electrode for urological procedures are well known in the art and an example of a continuous flow resectoscope is disclosed in U.S. Pat. No. 3,835,842.

An article entitled "THE USE OF THE RESECTOSCOPE IN GYNECOLOGY" by Richard A. Auhll which appeared at pages 91 through 99 of the Oct. 11, 1990 issue of Biomedical Business International (the "Auhll Reference") disclosed the use of a uterine resectoscope system in the form of a continuous flow resectoscope using an electrosurgical electrode for performing intrauterine procedures.

The Auhll Reference discussed three electrode structures, namely: (1) an electrosurgical cutting loop to treat fibroid tissues; (2) a roller ball having a-smooth exterior surface for endometrial ablation (which is cauterization of the endometrium); and (3) electrosurgical needle to cut through and destroy tissue producing intrauterine synechia. In gynecological procedures, the voltage of the electrosurgical cutting currents are typically in the range of 225 volts to about 250 volts at a power level of between 60 watts and 100 watts.

In order to increase the efficiency of treatment of the prostrate tissue generally, and the treatment of benign hypertrophy of the prostrate (BPH) in particular, several new procedures and devices have been developed. These procedures and devices include the use of a Nd:YAG laser for the coagulation and vaporization of prostate tissue generally referred to as abdominal tissue. In order to use Nd:YAG lasers for treatment of BPH, optical fibers capable of deflecting a Nd:YAG laser energy beam about 70.degree. to about 90.degree. to the axis of the optical fiber (generally known as side-firing fibers) have been developed.

Use of a direct contact laser fiber is discussed in an article entitled "TRANSURETHRAL EVAPORIZATION OF PROSTATE (TUEP) WITH ND:YAG LASER USING A CONTACT FREE BEAM TECHNIQUE: RESULTS IN 61 PATIENTS WITH BENIGN PROSTATIC HYPERPLASIA" by Perinchery Narayan, M.D., George Fournier, M.D., R. Indudhara, M.D., R. Leidich, M.D., K. Shinohara, M.D. and Alex Ingermann, M.D. which appeared at pages 813 through 820, in the June, 1994, Volume 43, Number 6, Issue of Urology (the "Narayan et al. Reference"). The Narayan et al. Reference discusses the use of laser surgery for BPH as a promising alternative to traditional TURP. The Narayan et al Reference discloses that in prostate surgery tissue evaporization referred to as Transurethral Evaporization of Prostate Tissue ("TUEP") was achieved by holding the laser fiber in contact with the area to be treated. The TUEP was performed using an Ultraline Laser Fiber manufactured by Heraeus LaserSonics, Milpitas, Calif. The Ultraline Laser Fiber uses a 600 .mu.m internal reflector fiber covered by a quartz glass cap that reflects the Nd:YAG beam at 80 degrees to the fiber axis. This fiber transmits a high-power density beam (spot size of 700 .mu.m and divergence of 17 degrees, giving a power density at 60 watts to 80 watts of 15,600 to 21,231 W/cm.sup.2) 1 mm from the fiber tip. A 23 French cystoscope (CIRCON ACMI, Stamford, Conn.) equipped with an 8 French laser bridge and a continuous flow system was used for the procedure.

The results as state in the Narayan et al. Reference was as follows:

" . . . Tissue evaporation was achieved by holding the laser fiber in contact with the area to be treated, and by dragging at a rate of 1 cm/20 seconds of laser energy delivery. At the beginning of each furrow dragging was commenced one bulling was seen indicating tissue evaporation. Dragging the fiber at a rate of 1 cm/20 seconds resulted in a furrow 5 to 7 mm deep with a 3 to 4 mm rim of coagulated tissue immediately next to it."

Another known prior art device for treatment of prostate tissue was presented at a poster session at the Society of Minimal Invasive Therapy ("SMIT") on Nov. 5, 1993. The poster session was entitled "TRANSURETHRAL VAPORIZATION OF THE PROSTATE (T.V.P.): NEW HORIZONS" by Irving M. Bush, M.D., Edward Malters, M.D. and Jan Bush, R.N. (the "Bush et al. Reference") disclosed the use of an improved scored ball loop produced by CIRCON ACMI Division of Circon Corporation, assignee of the present patent application, with a continuous flow resectoscope for providing transurethral desiccation (vaporization) of the prostrate.

The Bush et al Reference states as follows:

"T.U.D (transurethral desiccation of the prostate) was first described in 1874 by Bottini. Since 1966 we have used this visually controlled exact vaporization of the prostate in over 500 men with benign hypertrophy, cancer and bladder neck disease.

In the present method (T.V.P., transurethral vaporization of the prostate) a grooved ball electrode and pure electrosurgical cutting current is used to sculpt out the prostatic bed. T.V.P. has the advantage that it causes little or not bleeding, fluid absorption or electrolyte imbalance. Since the residual desiccated tissue (adequate for pathologic review) is removed at the end of the procedure, there is no slough or delayed bleeding (open vessels are closed without retraction). The patient can leave the hospital, voiding (76%) within the 23 hour observation time in most instances. A new improved scored ball loop (A.C.M.I.) to be used with a continuous flow resectoscope has become available.

T.V.P. is a short procedure without sphincter damage which preserves antegrade ejaculation and has a low (2-3%) subsequent procedure rate. Our experience with the last 100 consecutive patients will be detailed."

For purposes of background in electrosurgical treatment of tissue, there are three basic electrosurgical modes: (a) cutting (dissecting) where tissue is severed by a cutting electrode having a radio frequency ("R.F.") cutting current applied to the cutting electrode and the wounded tissue has a layer of coagulation of about 0.5 mm to about 1 mm beyond the cutting area; (b) fulguration where a ball electrode is positioned above the tissue to be treated and an R.F. arc coagulating current flashes from the ball electrode to the tissue to be treated coagulating the tissue; and (c) desiccation where a smooth ball electrode is held in direct contact with the tissue to be treated and a coagulating current of a selected magnitude is applied to the ball electrode vaporizing the tissue.

The first use of electrosurgical generator for prostatic resection using only an R.F. cutting current was in 1931, and the electrosurgical generator was a McCarthy Surgical Unit Type 504A sold by the Complex Oscillator Corporation (the "McCarthy Surgical Unit"). The McCarthy Surgical Unit was a highly efficient vacuum tube generator producing sustained oscillation of high frequency.

The McCarthy Surgical Unit was capable of being used for numerous procedures including prostatic resection. The McCarthy Surgical Unit manual states the following with respect to prostatic resection:

"With the wide interest shown in the relief of prostatic encroachment by the intravesical route, we offer this apparatus as the only present day means for actuating some of the electrodes used for this purpose. The splendid action of this current in a liquid medium has eliminated the hazard of failure at the current source.

The method advocated by Dr. Joseph F. McCarthy, for whom this apparatus was designed, permits great flexibility and with proper technique, the entire prostatic urethra can be remodeled.

The Stern Resectoscope under the able guidance of Dr. T. M. Davis has been modified for greater durability and effectiveness. Other surgical methods that have required the use of high frequency currents have been spurred to new activity.

Here again the requirements have been fully and adequately met and an excess of power provided that will encourage continued research. Those engaged in this specialty are freed of the limitations imposed by generators hitherto available.

In the practice of urology the McCarthy Unit provides every modality. Every purpose which requires the use of high frequency current is served; fulguration of cysts, papillomata, tumors, etc., coagulation control of bleeding, resection and treatment.

The current supplied by the type 504-A unit although very efficacious in resection, shows no effect on delicate insulating materials, greatly prolonging the useful life of urological instruments and electrodes. The selective foot switch permits hemorrhage control with the same electrode used for resection, without the necessity of changing the controls on the apparatus."

The McCarthy Surgical Unit manual states that the McCarthy Surgical Unit can be used for coagulation as follows:

"The unit generates by one type of current, and the controls merely provide the means for adjusting its intensity. It has been established that the same current that shows such admirable cutting characteristics is also the most effective for coagulation. By virtue of its penetrating quality the time necessary for coagulating tumor masses or malignancies has been greatly reduced. Sections of coagulated areas show a tapering off into unaffected tissue that practically eliminates the possibility of secondary hemorrhage. Tumor masses show a remarkable shrinkage during application, proportional to their fluid content.

The technique used in coagulation with this type of current is the same as used for tissue destruction and for hemorrhage control. The electrode must be placed in contact with the area to be treated before the current is turned on. After treatment the current must be off before the electrode is removed. No attempt should be made to ply the area with sparks. In following this technique there is no possibility of carbonization, and no tissue can adhere to the electrode."

The McCarthy Surgical Unit utilized for coagulation and dissection a smooth ball shaped electrode having a 3/16 inch (4 mm) diameter.

The McCarthy Surgical Unit utilized a control panel having two dials. The first dial was referred to as the Range Selector (R.S.) having three ranges, a low, medium and high, each representing one third of the current output. The second dial was referred as the Current Intensity Control (C.I.C.) and provided smooth linear adjustment over each range. Thus, the Range Selector was a course adjustment and the Current Intensity Control was a fine adjustment. The only current produced by the McCarthy Surgical Unit was a cutting current. The maximum current was in the order of 2,600 milliamperes.

In the McCarthy Surgical Unit, for all operative work, dissection, coagulation, bladder fulguration, prostatic resection and the like, a plate electrode was placed under the patient and connected to an indifferent, terminal which is usually a ground terminal, to ground the patient.

In using the McCarthy Surgical Unit for prostatic resection, bleeding resulting from the removal and vaporization of tissue using high intensity cutting current was controlled by passing the same electrode over the same treated tissue area using a low intensity cutting current for providing coagulation of the treated tissue.

Typically, the resulting coagulation layer of the heated tissue had a thickness in the order of 0.5 mm to about 1 mm which appeared sufficient to stop bleeding.

A novel, new and unique electrode for a resectoscope for performing urological, gynecological and laparoscopic procedures is disclosed and taught by the present invention. In the preferred embodiment, the electrode comprises an electrode lead member having an elongated conductor member having a first end and a second end with an insulative cover extended therebetween. The first end of the electrode member has a protruding electrode which is adapted to be electrically connected to an electrosurgical generator. The second end of the electrode member terminates in an active member.

The electrode includes an electrode support member operatively connected to the loading member and includes an elongated semi-rigid bifurcated arm terminating in a conductive core spaced a predetermined distance from the active member. The electrode support member has a grooved slider having a central opening extending therethrough for fixedly mounting the grooved slider on the conductive core.

Also, a method for treating tissue is shown. The method comprises the steps of: (i) inserting a sheath having a visual obturator into a urethra; (ii) removing the visual obturator leaving the outer sheath in the urethra; (iii) inserting into a resectoscope working element a telescope and an electrode wherein the electrode has an electrode lead member which includes an elongated conductor member having a first end and a second end with an insulative cover extended therebetween wherein said first end has a protruding electrode adapted to be electrically connected to an electrosurgical generator and wherein said second end terminates in an active member and having an electrode support having an elongated semi-rigid bifurcated arm terminating in a conductive core spaced a predetermined distance from the active member and wherein the electrode support member has a grooved slider having a central opening extending therethrough for fixedly mounting the grooved slider on the hub; (iv) passing the resectoscope working element having the telescope and electrode mounted thereon into the sheath and visually positioning the grooved slider in the proximity of the tissue to be treated; (v) irrigating through the sheath the tissue to be treated with an irrigation fluid; and (vi) applying an electrosurgical cutting current to said grooved slider at a selected voltage level of between about 200 volts to about 300 volts and moving the grooved slider having an electrosurgical cutting current applied thereto over the tissue to be treated to ablate the tissue.

Each of the known prior art devices and method have certain disadvantages.

In performing TURP procedures, a urological procedure using state-of-the-art cutting loop electrodes, the potential of undesirable side effects on the patient such as retrograde ejaculation, incontinence and the required use of a foley catheter for a relatively long period of time, say in the order of 4 to 5 days or more, are becoming objectionable.

The use of laser fibers for treatment of prostatic tissue appears to have less traumatic effect on the patient. However, the efficiency of the procedure in terms of quantities of tissue removed, the technique for using the laser fibers, energy required in joules for vaporizing tissue and the resulting depth of the coagulated layer of tissue are deemed to be short comings to the potential long term use of laser fibers for laser prostatectomy.

The use of scored roller electrode in a resectoscope for treatment of prostatic tissue using cutting current R.F. signals appeared to show that a scored roller ball electrode would successfully vaporize prostatic tissue. However, the removal rate of tissue, the time required for completion of a procedure and the depth of the layer of coagulated tissue appeared to require significant improvement to increase the efficiency of the procedure relative to a laser fiber used for a similar procedure.

Therefore, the problem with the known prior art devices is that the operable power levels in terms of watts are higher than desired using a standard roller ball or a scored roller ball, the size of the craters of vaporized tissue formed in a unit of time is below the desired time verses vaporization results of tissue treatment, the time required to produce trenches of vaporized tissue is longer than desired and the thickness of remaining coagulated tissue is thinner than desired and requires additional coagulating time to develop a sufficient thick coagulate layer of tissue in the area of the treated vaporized tissue.

The grooved slider electrode of the present invention overcomes several of the problems associated with prior and electrodes and devices. The preferred embodiment of the present invention is in the form of a grooved slider which is fixedly attached to the conductive core. In the preferred embodiment, the treating surface has a plurality of raised rails which are capable of vaporizing tissue.

One advantage of the present invention is that the electrode having the grooved slider can be used with standard urological and gynecological resectoscopes.

Another advantage of the present invention is that the grooved slider may have a variety of geometrical shapes such as, for example, planar base having a support surface and a treating surface wherein the treating surface includes a connecting member having a central opening for receiving the conductive core and for rigidly attaching the slider electrode to the conductive core and wherein the treating surface has a plurality of spaced raised rails. The spaced raised rails may be in form of a plurality of spaced parallel rails. Also, the slider electrode can be in form of a sawtooth member. Alternatively, the treating surface could be in the form of a plurality of substantially parallel conically shaped teeth having a selected height and spaced formed therebetween. Another configuration is to form the treating surface into two sections, each of which have a different member of parallel rails and elongated spaces therebetween. It is desirable for the electrode configuration to have a large number of high current density areas.

Another advantage of the present invention is that the use of ridges, sawtooth teeth or conically shaped teeth having areas which maximize R.F. current concentration facilitate reduced power requirement, lower power settings on the electrosurgical generator and improved efficiency.

Another advantage of the present invention is that the protruding rails or teeth may have polished surfaces which minimize tissue sticking or adhesion. Thus, as the grooved slider is moved over tissue during treatment, the absence of tissue adhering to the surface of the protruding rails or teeth is desirable to maintain efficiency of vaporization.

Another advantage of the present invention is that the structure of the grooved slider is atraumatic in the non-energized mode.

Another advantage of the present invention is that the grooved slider may be used in urological procedures, gynecological or other procedures requiring tissue vaporization.

Another advantage of the present invention is that the grooved slider can be used with a resectoscope in performing a prostatectomy for treatment of BPH of the prostate.

These and other advantages of the invention will be readily apparent when considered in light of the detailed description hereinafter of the preferred embodiment and of the drawings which include the following figures:

FIG. 1 is a top, front and left side perspective view of a grooved slider electrode for use with a resectoscope;

FIG. 2 is a top view of a grooved slider shown in FIG. 1 having a treating surface formed of a plurality of spaced rails;

FIG. 3 is a front elevational view of a grooved slider shown in FIG. 1;

FIG. 4 is a right side elevational view of the grooved slider of FIG. 2;

FIG. 5 is a front elevational view of another embodiment of a grooved slider having raised rails in the form of substantially rectangular cross-section rails having a selected height and elongated slots formed therebetween;

FIG. 6(a) is a right side elevational view of the grooved slider of FIG. 4;

FIG. 6(b) is a right side elevational view of an eccentric grooved slider having a treating surface similar to that of the grooved slider of FIG. 5;

FIG. 7 is a front elevational view of another embodiment of a grooved slider having raised rails in the form of substantially triangular cross-section rails having a selected height and elongated slots formed therebetween;

FIG. 8(a) is a right side elevational view of the grooved slider of FIG. 7;

FIG. 8(b) is a right side elevational view of an eccentric grooved slider having a treating surface similar to that of the grooved slider of FIG. 8(a);

FIG. 9 is another embodiment of a grooved slider wherein the electrode is in the form of a sawtooth member having a plurality of spaced, triangular shaped slots having a selected depth forming a treating surface having at lease two spaced ridges;

FIG. 10 is a right side elevational view of the grooved slider of FIG. 9;

FIG. 11 is a front elevational view of another embodiment of a grooved slider having a treating surface in the form of single, elongated slot defining a trough having raised side rails;

FIG. 12(a) is a right side elevational view of the grooved slider of FIG. 11;

FIG. 12(b) is a right side elevational view of an eccentric grooved slider having a treatment surface similar to that of the grooved slider of FIG. 11;

FIG. 13 is a front elevational view of another embodiment of a grooved slider wherein the electrode is in the form of a plurality of spaced parallel teeth;

FIG. 14 is a right side elevational view of the grooved slider of FIG. 13;

FIGS. 15, 16 and 17 illustrate another embodiment of a grooved slider having a treating surface in the form of a plurality of spaced substantially parallel conically shaped teeth having a selected height and spaces formed therebetween.

FIGS. 18, 19, 20(a) and 20(b) illustrate another embodiment of a grooved slider having a treating surface in the form of two sections wherein a first section has two parallel rails having selected heights and elongated slots formed therebetween and a second section has three parallel rails having a selected height and elongated slots formed therebetween;

FIG. 21 is a schematic diagram of an electrosurgical generator operatively connected to a resectoscope;

FIG. 22 is a chart showing parameters for vaporization;

FIG. 23 is a block diagram of a method for using the grooved slider electrode in a urological procedure; and

FIG. 24 is a diagrammatic representation of a trough formed in a patient tissue using a grooved slider of the preferred embodiment.

In the perspective view of the grooved roller electrode of FIG. 1 shown generally as 20. The structure of the electrode is for use with a resectoscope. The electrode 20 includes an electrode lead member 22 having an elongated conductor member 26 having a first end 30 and a second end 32. An insulative cover 34 extends between the first end 30 and the second end 32.

The first end 30 has a protruding electrode 38 which is adapted to be electrically connected to an electrosurgical generator. The second end 32 terminates in an active member or a loading member shown generally as 40.

The active member 40 has an electrode support member, shown generally as 42, operatively connected to the loading member 40. The electrode support member 42 has an elongated semi-rigid bifurcated arm 46 which terminates in a conductive core 50 spaced a predetermined distance from the active member 40. The bifurcated arm 46 has an insulative covering formed thereon except in the portion thereof which forms the conductive core 50.

The electrode support member 42 has a grooved slider 48 having a central opening 54 extending therethrough for fixedly mounting the grooved slider 48 on the conductive core 50.

In the preferred embodiment, the electrode stabilizer 60 for stabilizing the grooved slider is proximate a distal region of a telescope mounted in a resectoscope working element. It is envisioned that the electrode 20 does not need the electrode stabilizer 60 in order to practice this invention. The distal end of a telescope is removeably supported by stabilizer 60. The stabilizer 60 has a pair of space resilient support arms 64 which define a hollowed out space 68 to receive a telescope.

The stabilizer 60 is made of a resilient and flexible dielectric material, generally an insulating material, and resiliently literally mount the electrode to a telescope and insulates the electrode 20 from a telescope.

FIGS. 2, 3 and 4 depict the preferred embodiment of a grooved slider 48 generally in the form of a planar base 58 having a support surface which includes a connecting member. The connecting member has a central opening 56 for receiving the conductive core 50 and for rigidly attaching the grooved slider to the conductive core 50. The grooved slider has a treating surface having a plurality of spaced raised rails 52. The typical depth of the rails 52 would be in the order of 0.012 inches (3 mm) and the width of the slots therebetween would be in the order of 0.015 inches (4 mm). The diameter of the support base would be in the order of 0.115 inches to about 0.160 inches (3 to 4.5 mm).

FIG. 5 illustrates another embodiment of a grooved slider 70 having a trapezial front view with a connecting member 72 at the top thereof and a treating surface located on the bottom thereof having raised rails 76. In this embodiment, the treating surface raised rails 76 are in the form of substantially rectangular cross-sectional rails having a selected height and having elongated slots 74 formed therebetween. Raised side rails 78 are formed along the edges of the treating surface.

The grooved slider 70 has a central opening 80 which is adapted to receive and be fixedly attached to the conductive core 50 as shown in FIG. 1.

The right side elevational view of FIG. 6(a) illustrates that the grooved slider 70 of FIG. 5 is symmetrical and has a central opening 80 which is adapted to be fixedly attached to the conductive core 50 as shown in FIG. 1.

FIG. 6(b) illustrates a right side elevational view of an eccentric of a grooved slider similar to that of FIG. 5 which is shown as 70. The grooved slider has a top 72, a central opening 80 and a treating surface which is similar to that shown on FIG. 5.

FIG. 7 illustrates another embodiment of a grooved slider 90 raised rails in the form of substantially triangular cross-sectional rails having a selected height and having elongated slots 94 formed therebetween. Raised side rails 98 are formed along the edges of the treating surface.

The grooved slider 90 has top 92 defining a central opening 100 which is adapted to receive and be fixedly attached to the conductive core 50 as shown in FIG. 1.

FIG. 8(a) illustrates in a side elevational view the grooved slider 90 of FIG. 7. The grooved slider 90 as illustrated in FIG. 7 is symmetrical and has a top 72 and a central opening 100.

FIG. 8(b) illustrates a right side elevational view of an eccentric grooved slider 90 which is similar to that of FIG. 7. The grooved slider 90 has a top 72, a central opening 100 and a treating surface which is similar to that shown in FIG. 7.

FIGS. 9 and 10 illustrate another embodiment of a grooved slider 110 wherein the electrode is in the form of a sawtooth member having a plurality of spaced, triangular shaped slots having a selected depth and vertex or ridge 106 forming a treating surface having at least two spaced ridges. Side conductors 104 are electrically connected to leads 102 which form part of the bifurcated arm 42 illustrated in FIG. 1.

FIG. 11 illustrates another embodiment of a grooved slider, shown generally as 120, having a treating surface in the form of a single elongated slot 124 defining a trough having raised side rails 128. The grooved slider 120 has a top 122 and an elongated opening 130 which extends axially through the grooved slider 120. the grooved slider 120 is adapted to be fixedly mounted on the conductive core 50 illustrated in FIG. 1.

FIG. 12(a) illustrates in a right wide elevational view that the grooved slider, shown generally as 120 of FIG. 5, is symmetrical and has a central opening 130 which is adapted to fixedly mount the grooved slider 120 to the conductive core 50 as shown in FIG. 1.

FIG. 12(b) illustrates a right side elevational view of an eccentrical of a grooved slider similar to that of FIG. 11. The grooved slider 120 has a top 122, a central opening 130 and a treating surface which is similar to that shown in FIG. 11.

FIGS. 13 and 14 illustrate another embodiment of a grooved slider 136 wherein the electrode is in the form of a plurality of spaced, parallel teeth 140 formed by coils of wire 140. The structure of the teeth and the slots forming a treating surface having at least two spaced ridges is similar to the electrode described in FIGS. 9 and 10.

FIGS. 15, 16 and 17 illustrate another embodiment of a grooved slider 150 having a treating surface in the form of a plurality of spaced, substantially parallel conically shaped teeth 154 having a selected height and spaces 156 formed therebetween. The grooved slider 150 has a connecting member having a top 72 and a central opening 158 which is adapted to receive and be fixedly attached to the conductive core 50 as shown in FIG. 1.

FIGS. 18, 19, 20(a) and 20(b) illustrate another embodiment of a grooved slider 160 having a treating surface in the form of two sections 162 and 164. The first section 162 has two parallel rails 168 having selected heights and elongated slots 170 formed therebetween. The second section 164 has three parallel rails 176 having selected heights and elongated slots 180 formed therebetween.

The grooved slider 160 is mounted by the surface opposite to the treating surface to the conductive core 30 of FIG. 1.

FIG. 21 is a schematic diagram of an electrosurgical generator 190 which is operatively connected to a resectoscope 194 including a working element. The electrosurgical generator 190 produces typical R.F. electrosurgical currents which may be a cutting current, a blend current or a loop current. A description of typical R.F. electrosurgical currents is set forth at pages 96 through 97 and page 100 of the Valleylab SSE4 Instruction Manual.

The electrosurgical current from the electrosurgical generator 190 is applied by the grooved slider electrode 20 and the grooved slider 48 to a patient tissue to be treated, shown by tissue 198.

A dispersive electrode or patient plate, shown as 202, is affixed to the patient, shown by arrow 196, usually by means of a conductive gel. The dispersive electrode 202 is electrically connected to an isolated terminal 206. In order to complete the electrical path back to the electrosurgical generator 190, the electrosurgical generator 190 is electrically connected to the isolated terminal 206.

Thus, the patient 196 is part of the electrically conductive path. As such, the areas of high concentration of R.F. electrosurgical current which form on the protruding ridges, such as, for example, ridges 52 of the grooved slider 48, result in areas of increased current density which electrically interact with the tissue being treated. During treatment, the grooved slider 48 is moved gently over the tissue allowing the grooved slider 48 to move without much pressure, not unlike moving a hot knife through butter, vaporizing the tissue forming a trough therein. This is discussed further in connection with FIG. 24. In this environment, the grooved slider 48 functions as an active electrode while the patient grounding plate functions as a dispersive electrode.

FIG. 22 shows a table of parameters for vaporization using the teachings of the invention. The procedure can be performed with the grooved slider in either air or liquid as a medium. As shown by the table of FIG. 21, air provides less electrical resistance such that an electrosurgical voltage of about 200 volts and a power level of between 160 watts to 240 watts will provide the desired cutting action. An electrical surgical voltage of about 300 volts in air produces charting resulting in a tissue layer having high resistance, which is undesirable.

In liquid and as shown by the table of FIG. 22, an electrosurgical voltage of about 300 volts and a power level of between 160 and 240 watts produces the desired cutting action while an electrosurgical voltage of about 400 volts to about 500 volts produces charring of the tissue.

A method for treating tissue can be performed using the grooved slider of the present invention. FIG. 23 illustrates the steps of the method. The method comprises the steps of inserting a sheath, which may be an outer sheath for a continuous flow resectoscope (CFR), having a visual obturator into a urethra as shown by 210.

The step of removing the visual obturator leaving the outer sheath in the urethra is shown by step 212. Step 214 provides for inserting into a resectoscope working element a telescope and an electrode wherein the electrode has an electrode lead member includes an elongated conductor member having a first end and a second end with an insulative cover extended therebetween wherein said first end has a protruding electrode adapted to be electrically connected to an electrosurgical generator and wherein said second end terminates in an active member and having an electrode support having an elongated semi-rigid bifurcated arm terminating in a conductive core spaced a predetermined distance from the active member and wherein the electrode support member has a grooved slider having a central opening extending therethrough for rotatably mounting the grooved slider on the conductive core.

Step 216 provides for passing the resectoscope working element having the telescope and electrode mounted thereon into the outer sheath and visually positioning the grooved slider in the proximity of the tissue to be treated.

Step 218 provides for irrigating through the outer sheath the tissue to be treated with an irrigation fluid. However, this step is not required if a non-continuous flow resectoscope is used.

Step 220 provides for applying an electrosurgical cutting current to the grooved slider at a selected voltage level of between about 200 volts to about 300 volts.

Step 220 also provides for moving the grooved slider having an electrosurgical cutting current applied thereto over the tissue to be treated to vaporize the tissue.

In the preferred embodiment, the method for treating prostate tissue comprises the step of irrigating through an instrument the prostate tissue to be treated and applying a high electrosurgical cutting current to grooved slider at a selected voltage level of between about 200 volts to about 300 volts, and moving the grooved slider having the electrosurgical cutting current applied thereto over a selected portion of prostate tissue to be treated to vaporize the tissue and form a trough having a coagulation layer of treated tissue of at least 2 mm.

FIG. 24 is a pictorial representation of a tissue area shown by 230, such as a prostate, wherein the grooved slider 48 supported by bifurcated arm 46 has formed a crater or trough 196 having side walls 232.

In utilizing the grooved slider electrode 48 a shown in FIG. 24, the velocity of movement of the grooved slider 48 in prostate tissue is approximately 5 mm/sec. The depth of the trough (height of sidewalls 232) is in the order of 3 mm.

The R.F. electrosurgical setting cooperates with the raised ridges or protrusions to form areas of increased current densities which generate sufficient current flow at the appropriate voltage levels to vaporize the tissue. The tissue surrounding the vaporized tissue becomes coagulated by the R.F. electrosurgical current at the boundary of the vaporized tissue resulting in a layer of necrosed tissue around the side walls 232 and trough 234. The thickness of the coagulated layer is in the order of about 1.5 mm to about 2 mm. Energy settings in the range of 160 watts to about 250 watts is desired, with the preferred power settings to be about 200 watts.

The preferred embodiment shown and described herein is directed for use in a urological procedure. This is an exemplary use and it is envisioned that the principle and teaching herein could be adapted for other procedures.

As an example, the electrode structure could be designed for use in a gynecological procedure with a gynecological resectoscope for performing endometrial ablation of the uterus or debulking myomas.

Also, various other configurations for the design of the grooved slider are envisioned and the preferred embodiment and species disclosed and described herein are exemplary and are not intended to restrict the inventor to the exemplary configuration disclosed herein.