MXPA98007192A - Electrochirurgic device to avoid the capacitive coupling and formation of corrie trajectories - Google Patents

Abstract

A monopolar electrosurgical device suitable for cutting and coagulating tissue is described. The device includes a trocar unit (32) and a probe unit (34). The trocar unit (32) has an insulated portion (44) and a conductive guide portion (36). The conductive guide portion (36) defines a conduit with the probe unit (34) slidably received therein. The probe unit (34) includes a conductive probe (54) with a proximal end and a distal end. Surrounding the probe (54) is an insulating layer (58) extending from the distal end of the probe. A conductive shield (60) is connected to the insulating layer (58) and also surrounds the probe (54). The conductive shield (60) is electrically connected to the conductive guide portion (36) of the trocar unit (3).

Description

ELECTROQUIRURGICQ DEVICE TO AVOID CAPACITIVE COUPLING AND THE FORMATION OF CURRENT TRAJECTORS UNDESIRABLE FIELD OF THE INVENTION The present invention relates to electrosurgical devices and, in particular, to a monopolar electrosurgical device having a probe that extends through a trocar where the probability of capacitive coupling and the formation of undesirable current paths reduce to a minimum.

BACKGROUND OF THE INVENTION Systems that use high frequency electric current for the cutting and / or coagulation of human tissue are well known in the art. Normally, electrical current is applied to the preselected tissue using a probe. The probe is energized by an electrosurgical generator. The current emanating from the probe destroys the preselected tissue producing a high temperature region around the tip of the probe. The current flows back to the electrosurgical generator by means of a return electrode that is connected to the patient. Referring to Figure 1, a P15_6 / 98MX schematic view and an enlarged cross-sectional side view of a prior art system 10 for cutting and / or coagulating the tissue with a high frequency electric current. As stated above, the system 10 includes an electrosurgical generator 12, a return electrode 14 and a cylindrical electrode probe 16 that is slidably received within a sleeve or metal trocar cannula 18. The probe 16 is surrounded by material of insulation 20 extending from tip 22 of the probe and through sleeve 18 of the trocar. The probe 16 is connected by the conductor 24 to the output terminal of the generator 12. The generator 12 is of the conventional type and the return terminal of the generator is connected, via the conductor 26 to the return electrode 14. While the System 10 of the prior art is effective for cutting and / or coagulating human tissue, the use of this system can also cause several serious problems. For example, the conductive elements placed around the probe 16 may become charged. The load is caused by the current flowing through the probe 16 and a dielectric (i.e., insulation 20) that is placed between the probe and any other P1526 / 98MX conductive elements such as the metal trocar 18. The loading of the conductive elements around the probe is commonly known as capacitive effect. Correspondingly, the charged elements will dissipate their energy in the form of a leakage current. The current will flow through either a path in the patient's body or through any other easily available ground return path. As the leakage current flows through the patient's body, the current can cause serious damage. For example, the current of loaded trocar 18 can cause severe burns as it travels back through the patient's body and toward the return electrode 14. The resulting burns can vary from minor damage to the skin surrounding the area where the trocar 18 joins the patient, until severe burns in organs such as the intestines. Personnel who come in contact with any of the charged metal structures may also be burned as the leakage current passes through their body and into a potential ground. As indicated above, trocar 18 can accumulate a significant load. In this case, the energy inside the trocar will dissipate through the patient and anyone who comes into contact with it.

P1526 / 98MX Personnel coming into contact with trocar 18 also provides an alternate ground return path for the current that is emitted from tip 22 of the probe. Therefore, serious damage to the patient may occur since the current uses the alternative ground return path provided by the trocar 18"landed". Correspondingly, the present invention provides a device that overcomes or at least minimizes the aforementioned problems by reducing the likelihood of undesirable capacitive coupling and the formation of undesirable current paths.

SUMMARY OF THE INVENTION The present invention provides a monopolar electrosurgical device that minimizes the likelihood of capacitive coupling and the formation of undesirable alternating current paths while the high frequency electrical current is used in a surgical procedure to destroy a preselected tissue. The device that gives body to the present invention is especially suitable for directing the high-frequency electric current to the preselected regions within a patient. The coupling Capacitive P152S / 98MX of the conductive elements, such as the trocar, is minimized. In addition, the present device reduces the likelihood that the trocar will provide an alternating path for the return of the electric current supplied to the body of a patient. The electrosurgical device that embodies the present invention includes a trocar unit and a probe unit. The trocar unit has an isolated portion and a conductive guide portion. The conductive guide portion forms a conduit for the probe unit that is slidably received therein. The probe unit includes a conductive probe with a proximal end and a distal end. There is an insulating layer around the probe extending from the distal end of the probe. Attached to the insulating layer and also surrounding the probe is a conductive shield. The conductive shield is associated conductively with the conductive guide portion of the trocar unit.

BRIEF DESCRIPTION OF THE DRAWINGS OR FIGURES In the accompanying drawings that are part of the specification, and in which similar numbers are used to designate similar parts throughout the specification: Figure 1 is a side view in section Transverse P1526 / 98MX increased and schematic illustrating a prior art system for cutting and / or coagulating tissue with high frequency electrical current; Figure 2 is an enlarged cross-sectional side view of an electrosurgical device in accordance with the present invention; Figure 3 is an enlarged and schematic cross-sectional side view illustrating the electrosurgical device of Figure 2 within a system for cutting and / or coagulating the tissue of a patient; Figure 4 is an enlarged cross-sectional side view of an electrosurgical device embodying the present invention; Figure 5 is an enlarged cross-sectional side view of a further embodiment of the present invention; Figure 6 is an enlarged cross-sectional side view of another electrosurgical device in accordance with the present invention. Figure 7 is an enlarged cross-sectional side view of an additional electrosurgical device in accordance with the present invention; Figure 8 is an enlarged cross-sectional side view of another electrosurgical device P1526 / 98MX in accordance with the present invention; and Figure 9 is an enlarged cross-sectional side view of another electrosurgical device embodying the present invention.

DETAILED DESCRIPTION OF THE MODALITIES PREFERRED EMBODIMENTS OF THE INVENTION The present invention provides a monopolar electrosurgical device that minimizes the likelihood of capacitive coupling and the formation of undesirable current paths, while using high frequency electrical current to destroy preselected tissue within a patient. The electrosurgical device includes a trocar unit and a probe unit. The trocar unit has an isolated portion and a conductive guide portion associated therewith. The probe unit is slidably received within a conduit defined by the conductive guide portion of the trocar unit. The probe unit includes a conductive probe with a proximal end and a distal end. Around the probe there is an insulating layer extending from the distal end of the probe to the proximal end of the probe. A conductive shield surrounds at least a portion of the probe and is part of the probe unit. The driver shield is part of a trajectory P1526 / 98MX conductive including the conductive portion of the trocar unit. Referring to the drawings and, particularly, to Figure 2, a monopolar electrosurgical device 30 includes a trocar unit 32 and a probe unit 34. The trocar unit 32 has a conductive guide 36 that is partially surrounded by an insulating layer 38. The conductive guide 36 can be made of a conductive material such as a metal or a metallic alloy. A typical construction material of the conductive guide 36 is stainless steel. Conversely, the insulating layer 38 is made of an insulating material such as a plastic material or a ceramic material having the appropriate dielectric properties. The conductive guide 36 is generally tubular in shape and has a proximal end 39 of the probe, an open distal end 40 and an open conduit 41 extending therebetween. The open distal end 40 of the guide 36 is tapered to form a pointed prong 42 around the opening of the conduit 41. Additionally, extending radially outwardly from the proximal end 39 of the guide probe 36 is a flange 43 surrounding to the open conduit 41. The insulating layer 38 envelops the external surface 44 of the conductive guide 36. The insulating layer 38 P1526 / 98MX extends from the open distal end 40 of the conductive guide 36 to the flange 43 and may also cover a portion of the flange 43. The insulating layer 38 generally conforms to the shape of the outer surface 44 and provides an end pointed or pointed 45 as well as a flanged end 46 that abuts the flange 43 of the conductive guide 36. As shown in Figure 2, the outer diameter 49 of the insulation flange 47 is smaller than the outer diameter 50 of the conductive flange 43. However, in other embodiments, the outer diameter of the insulation flange may be equal to, or greater than, the outer diameter of the conductive flange. Received slidably within conduit 41 of the trocar unit is probe unit 34. Probe unit 34 has a proximal end 52 and a distal end 53 which protrude respectively from the proximal end 39 of the probe and of the probe. sharpened end 45 of the trocar unit 32. Extending along the center of the probe unit 34 is a conductive probe 54. The probe 54 is of generally tubular construction, is made of a conductive material which may be a metal, a metal alloy or similar and has an electrode, such as a curved tip 56 protruding from distal end 53. The electrode of the probe P1526 / 98MX can have other forms, such as straight or blunt, as is well known in the electrosurgery technique. Around the probe 54 there is an insulating layer 58. The insulating layer 58 can be a plastic material, a ceramic material or a composite material having the appropriate dielectric properties. The insulating layer 58 is generally tubular in shape and covers the probe 54 substantially along its entire length from the distal end 53 to the proximal end 52. Thus, only the tip of the probe 56 and the proximal end 52 of the probe 54 project from below the insulating layer 58. Embedded within the insulating layer 58 of the probe, there is a conductor 62 and a conductive shield 60 made of a conductive material, such as a metal or a metal alloy. The shield 60 is cylindrical and in this particular embodiment extends substantially over the entire length of the probe body 54 from the proximal end 52 to the distal end 53 of the probe. The shield 60 does not come into contact with the probe 54 due to the isolation 58 between the probe 54 and the shield. The lead 62 provides a conductive path from the shield 60 to the trocar unit 32 and to the return terminal of an electrosurgical generator. The conductor 62 is electrically connected to the P1526 / 98MX shield 60 and extends through the insulation 58 to the conductive guide portion 36 of the trocar unit 32. Turning now to Figure 3, the monopolar electrosurgical device 30 of Figure 2 is shown within a system 110 for cutting and / or coagulation of tissue 64 within a patient. As previously stated, the return electrode 14 is attached or connected to the patient and, via the lead 26, to the return terminal 13 'of the electrosurgical generator 12. In the same way, the lead 62 extending both from the trocar 32 as from the probe unit 34 and is operatively connected to the return terminal 13 of the electrosurgical generator 12. Finally, the output terminal 15 of the electrosurgical generator 12 is operatively connected, via the lead 24, to the electrode probe 54. The high frequency electric current produced by generator 12 passes through probe 54 and is emitted from tip 56 of the probe. The stream 68 then continues through the tissue 64 of the patient and towards the return electrode 14, where it travels back to the generator 12. As shown in Figures 2 and 3, the conductive guide 36 of the trocar 32 provides a path of controlled current return to generator 12 for P1526 / 98MX any leakage current because the trocar is connected, via the conductor 62, to the return terminal 13 of the generator. However, the conductive guide 36 does not provide an alternative return path for the main electrical current 68 emanating from the tip 56 of the probe 54 due to the insulation 38 between the conductive guide 36 and any tissue of the patient. Therefore, the insulation 38 also does not provide an undesirable and uncontrollable resistive current path between the probe 54 and the trocar unit 32. As previously indicated, the high frequency electrical current that passes through the probe 54 and the dielectric provided by the insulation 58 that surrounds the probe, it is generated in an electrostatic field 69 that is radiated radially along the entire length of the probe. This field 69 can cause capacitive coupling between the probe 54 and other conductive elements located around the probe. However, as the electrostatic field 69 emanates from the probe 54, the field energy is absorbed by the shield 60 and transported, via the conductor 62, to the return terminal 13 of the generator 12. Therefore, any conductive elements placed around the electrosurgical device 30 are not capacitively coupled because the field The electrostatic P152S / 98MX 69 emanating from the probe 54 is absorbed by the conductive shield 60. Any portion of the field 69 that can escape (ie, leak) from the shield 60 is radiated along the length of the probe unit 34. Correspondingly, any electrostatic field 70 due to leakage within the trocar conduit 41 strikes the conductive guide 36. In this way, this field energy is also absorbed by the conductive guide 36 and drained, via the conductor 62, towards the return terminal 13 of the generator 12. In this way, the trocar 32 does not become charged by the capacitive coupling because all the electrostatic energy hitting the trocar is drained to the return terminal 13 of the generator 12. Figure 4 shows another embodiment of the present invention. The electrosurgical device 130 includes a trocar unit 132 and a probe unit 134. The trocar unit 132 has a conductive guide 136 which is generally tubular in shape and has a probe proximal end 139, a distal end 172 and a bore 137 that extends between these. The conductive guide 136 is made of a conductive material, such as a metal or a metallic alloy. Extending radially outward from the proximal end 139 catheter receiver of the guide 136 there is a flange Conductive P_.526.98MX 143. Attached to the distal end 172 of the conductive guide 136 is an insulated guide 138. Like the conductive guide 136, the insulated guide 138 generally has a tubular shape and a proximal end 146, a pointed or pointed end 145 and a hole 148 that extends between them. The insulated guide 138 is made of a dielectric material such as a plastic or a ceramic. The pointed or pointed end 145 of the isolation guide 138 is tapered to form a sharp pointed tip 142 around the opening of the hole 148. In addition, at the proximal end 146 of the guide 138 the flange 147 is provided and extended to The outer diameter 149 of the insulated flange 147 is smaller than the outer diameter 150 of the conductive flange 143. The insulated guide 138 may also have cords 151 around the outside of the guide and adjacent to the flange 147 if These ropes can provide a means for securing the trocar unit 132 to the patient The bore 137 within the lead guide 136 and the bore 148 within the isolation guide 138 are axially aligned such that a conduit is provided. open 141 from the proximal end 139 catheter receiver of the trocar unit 132 to the sharpened end 145.

P1526 / 98MX Extending within the trocar duct 141, there is a conductive strip 135 that serves as a contact with the conductive shield 160 described later. The conductive strip 135 is made of a resilient conductive metal and is attached or connected to the conductive guide 136. The conductive strip 135 extends from the conductive portion 136 to the insulated guide 138 of the trocar unit 132. Received within the conduit 141 of trocar, is the probe unit 134. The probe unit 134 has a proximal end 152 and a distal end 153 protruding respectively from the probe proximal end 139 and the sharpened end 145 of the trocar unit 132. Extending to length of the center of the probe unit 134 is a conductive probe 154. The probe 154 is generally of tubular construction, is made of a conductive material, such as for example a metal or a metal alloy and has a curved tip electrode 156 protruding from the distal end 153. Around the probe 154 there is an insulating layer 158. The insulating layer 158 can be a plastic material or a ceramic material. The insulating layer 158 is generally tubular in shape and covers the probe 154 from the distal end 153 to the proximal end 152. In this way, only the tip 156 of the probe and the proximal end 152 of the probe 154 project from the insulation 158.

P1526.98MX Partially embedded within the isolation probe 158 is a conductive shield 160 made of a suitable conductive material. The shield 160 is cylindrical in shape and extends from within the trocar unit 132 to the distal end 153 of the probe. The shield 160 is partially embedded within the insulation 158, such that it does not contact the probe 154. However, an exposed portion 161 of the shield projects or protrudes from the insulation 158 and is contained within the trocar conduit 141 adjacent to the Proximal end 152 of the probe unit 134. Pressing against the exposed portion 161 of the shield 160 and in electrical contact therewith is a conductive strip 135. As the probe unit 134 slides within the trocar duct 141, the strip 135 it remains in electrical contact with the shield 160. Correspondingly, the conductive strip 135 provides a conductive path from the shield 160 to the conductive portion 136 of the trocar unit 132. Additionally, a conductor 162 connects the conductive portion 136 of the unit of trocar 132 with the return terminal of an electrosurgical generator. During preparation for use in an electrosurgical procedure, the trocar 132 is connected to a patient in such a way that the flange 147 meets the P1526 / 98MX patient. In addition, the return electrode, such as electrode 14 of Figure 3 is connected to both the patient and the return terminal of the electrosurgical generator. In the same way, the conductor 162 extending from the trocar unit 132 is connected to the return terminal of the generator. Finally, the output terminal of the generator is connected to the electrode probe 154. During the electrosurgical procedure, the high frequency electric current produced by the generator is passed through the probe 154 and is emitted from the tip 156 of the probe. However, the electric current emanating from the tip 156 of the probe 154 can not use the conductive guide 136 as a resistive return path, due to the isolation 138 between the conductive guide and the patient. Therefore, an undesirable path of resistive current from the probe 154 to the trocar unit 132 can be avoided. The high frequency electric current passing through the probe 154 and the dielectric provided by the insulation 158 surrounding the probe , results in an electrostatic field that is radiated radially along the entire length of the probe. However, as the electrostatic field emanates from probe 154, it strikes conductor shield 160.

P1526 / 98MX Consequently, the field energy is absorbed by the shield 160 and transported, by the conductive strip 135, the conductive guide 136 and the conductor 162, to the return terminal of the generator. Therefore, any of the conductive elements placed around the electrosurgical device 130 will not be capacitively coupled because the electrostatic field emanating from the probe 154 is absorbed by the conductive shield 160. Additionally, any portion of the field that comes in contact with the guide conductor 136 is absorbed by the guide and drained by the conductor 162, towards the return terminal of the generator. Therefore, the trocar 132 does not become charged by the capacitive coupling, because all the electrostatic leakage energy is drained to the return terminal of the generator. Turning to Figure 5, an enlarged cross-sectional side view of another embodiment of an electrosurgical device 230 in accordance with the present invention is provided. The electrosurgical device 230 is similar to the electrosurgical device 130 shown in Figure 4, with the exception of the lid 274 connected to the conductive portion 236 of the trocar unit 232. In Figure 5, in the numbers of the 200 series, the two last digits represent the elements Structural P_.526.98MX that have a function similar to those described above and have numbers with the same last two digits. The lid 274 is disc-shaped with a hole 276 extending through its center. Located around the periphery of the cap 274 is an indented portion 278 that is threaded and engages the complementary cords 279 located around the trocar conduit 241 and adjacent the proximal end 239 of the probe. As shown in Figure 5, the bore 276 of the cap has a diameter that is smaller than that of the cylindrical shield 260. Therefore, through the bore 276 only the probe 254 and the surrounding insulation 258 can slide. cap 274 prevents exposed portion 261 of shield 260 from protruding from trocar conduit 241. In addition, the cap 274 prevents the proximal end 252 of the probe unit from extending too far away from the trocar unit 232. In this way, the electrical connection between the strip contact 235 and the exposed portion 261 of the shield 260 can be retained all the time during the use of the electrosurgical instrument. Referring to Figure 6, an enlarged cross-sectional side view of another is depicted P1526 / 98MX embodiment of an electrosurgical device 330 in accordance with the present invention. The device 330 includes a trocar unit 332 and a probe unit 334. The trocar unit 332 has a conductive guide 336 that is partially surrounded by an insulating layer 338. The conductive guide 336 is made of a conductive material, how can a metal or a metal alloy. Conversely, the insulating layer 338 is made of an insulating material such as a plastic, a ceramic or a composite. The conductive guide 336 is generally tubular in shape and has a proximal catheter end 339, an open distal end 340 and an open conduit 341 extending therebetween. Additionally, there is a flange 343 extending radially from the proximal end 339 that receives the guide probe 336. Partially enclosing the outer side 344 of the guide rail 336 and advancing inside the conduit 341 of the trocar is the insulating layer 338. The portion of the insulating layer 338 on the exterior 344 of the guide 336 extends over the open distal end 340 of the guide 336 and to the flange 343. Similarly, the portion of the insulating layer 338 within the conduit 341 is extends from the open distal end 340 of the guide and toward the proximal end 339 of the probe. Correspondingly, P152S / 98MX the insulating layer 338 is a tubular sheath with a tapered end 345 and a flanged end 346 abutting the flange 343 of the conductive guide 336. As shown in Figure 6, the outer diameter 349 of the flange 344 347 insulation is less than the outer diameter 350 of the conductive flange 343. The insulating layer 338 may also have ropes 351 around the exterior and adjacent to the flange 347. As stated above, the cords may provide a means for attaching the trocar unit 332 to a patient if desired. That portion of the insulation material 338 that extends within the trocar conduit 341 defines a channel 382 that allows access into the conduit 341 to the conductive guide 336. In this way, the channel 382 extends from the open distal end 340 and towards the proximal end of the guide probe 336. Connected to the conductive guide 336 and extending from the channel 382 and to the trocar conduit 341 there is a conductive strip 335. The conductive strip 335 is made of a resilient conductive metal and can being, as shown in Figure 6, connected to the conductive guide 336 at spaced intervals along the strip. Received inside trocar conduit 341 is P1526 / 98MX the probe unit 334. The probe unit 334 has a proximal end 352 and a distal end 353 which, respectively, project or protrude from the proximal end 339 of the probe and the sharpened end 345 of the unit of trocar 332. The conductive probe 354 extends along the center of the probe unit 334. The probe 354 is generally tubular in construction, made of a conductive material such as a metal or a metallic alloy, and it has a curved electrode tip 356 protruding from the distal end 353. An insulating layer 358 surrounds the probe 354. The insulating layer 358 may be a plastic material or a ceramic material. The insulating layer 358 is generally tubular in shape and surrounds the distal portion of the probe unit 334. However, the probe tip 356 of the probe remains exposed. Partially embedded within the insulation 358 of the probe, there is a conductive shield 360 made of a conductive material such as a metal or a metallic alloy. The probe 360 is substantially cylindrical, may be a solid layer or a wire mesh and extends from adjacent the distal end 353 of the probe 354 into the trocar conduit 341. Therefore, the shield 360 is embedded within the insulation 358, so that it does not contact the P1526 / 98MX probe 354 but only an exposed portion 361 of shield 360 protrudes or projects from insulation 358 within conduit 341 of the trocar. The exposed portion 361 is contained within the conduit 341 of the trocar and is generally located in the central portion of the probe unit 334. Pressing against the exposed portion 361 of the shield 360 is the conductive strip 335. The strip 335 remains in electrical contact with the shield 360 as the probe unit 334 slides within the trocar conduit 341. Correspondingly, the conductive strip 335 provides a conductive path from the shield 360 to the conductive portion 336 of the trocar unit 332. Additionally, a lead 362 connects the conductive portion 336 of the trocar unit 332 to the return terminal of a trocar 332. electrosurgical generator. As with the other modalities described above, before the device 330 is used in an electrosurgical procedure, the trocar 332 is connected or attached to a patient in such a way that the isolation 338 is located between the patient and the conductive guide 336. In addition , the patient's return electrode is in electrical contact with the patient and is also electrically connected to the generator's return terminal P1526 / 98MX electrosurgical. In the same way, the conductor 362 extending from the trocar unit 332 is connected to the return terminal of the generator. Finally, the output terminal of the generator is connected to the electrode probe 354. During the electrosurgical procedure, the high frequency electric current produced by the generator is passed through the probe 354 and is emitted from the tip 356 of the probe. However, for the electric current emanating from the tip 356 of the probe 354, the conductive guide 336 is not available as a resistive return path due to the isolation 338 located between the conductive guide 336 and the patient. However, the high frequency electrical current passing through the probe 354 and the dielectric provided by the insulation 358 surrounding the probe results in an electrostatic field that is radially emitted substantially along the entire length of the probe. However, as the electrostatic field emanates from the probe 354, it hits the conductive shield 360. Consequently, the field energy is absorbed by the shield 360 and transported, via the conductive strip 335, the conductive trocar portion 336 and the conductor 362 , to the return terminal of the generator. Therefore, any P1526 / 98MX conductive elements placed around the electrosurgical device 330 will not become capacitively coupled because the electrostatic field emanating from the probe 354 is absorbed by the conductive shield 360. Additionally, any portion of the field that comes into contact with the Conductive guide 336 is absorbed by the guide and drained, via conductor 362, towards the return terminal of the generator. Therefore, trocar 332 will not become charged by capacitive coupling because all electrostatic energy is drained to the return terminal of the generator. Referring to Figure 7, an enlarged cross-sectional side view of a further embodiment of an electrosurgical device 430 according to the present invention is depicted. The device 430 includes a trocar unit 432 and a probe unit 434. The trocar unit 432 has a conductive guide 436 that is partially surrounded by an insulating layer 438. The conductive guide 436 is made of a conductive material such as can be a metal or a metallic alloy. Conversely, the insulating layer 438 is made of an insulating material such as a plastic or a ceramic. The conductive guide 436 is generally tubular and P1526 / 98MX has a proximal end 439 catheter receiver, an open distal end 440 and an open conduit 441 extending therebetween. The open distal end 440 of the guide 436 is tapered or sharpened to form a pointed tip 442 around the opening of the conduit 441. The flange 443 extends radially outwardly from the probe proximal end 439 of the guide 436 probe. insulator 438 encloses the outer surface 444 of the conductive guide 436, extends from the open distal end 440 of the conductive guide 436 to the flange 443. Correspondingly, the insulating layer 438 generally conforms or adapts to the shape of the outer surface 444 including the sharpened end 445 and a flanged end 446 abutting the flange 443 of the conductive guide 436. As shown in Figure 7, the external diameter 449 of the insulation flange 447 is smaller than the external diameter 450. of the conductive tab 443. Received within the conduit 441 of the trocar unit is the probe unit 434. The probe unit 434 has a proximal end 452 and an end or distal 453 which protrude or protrude, respectively, from the proximal end 439 probe receiver and the sharpened end 445 of the trocar unit 432. Extending along the center of the probe unit 434 is a probe Conductive P1S26 / 98MX 454. The probe 454 has a generally tubular construction, is made of a conductive material such as a metal, a metallic alloy or the like, and has a curved electrode tip 453 projecting or protruding from the distal end 453. Surrounding the probe 454 is an insulating layer 458. The. insulating layer 458 can be a plastic material or a ceramic material having the appropriate dielectric properties. The insulating layer 458 extends from the distal end 453 of the probe unit 434 substantially to the proximal end 452. In this way, only the tip 456 of the probe and the proximal end 452 of the probe 454 project or protrude from the insulation 458. Embedded within the insulation 458 of the probe is a conductive shield 460 made of conductive material. The shield 460 is substantially cylindrical and extends from adjacent the distal end 453 of the probe 454 into the passageway 441 of the trocar. - The shield 460 is embedded within the insulation 458 in such a way that the shield does not protrude from the insulation and is not in electrical contact with the probe 454. Attached or connected to the shield 460 there is a conductor 462. The conductor 462 extends through the 458 insulation and also electrically connects to the P1526 / 98MX conductive guide portion 436 of the trocar unit 432. Correspondingly, the conductor 462 provides a conductive path from the shield 460 to the trocar unit 432. The lead 462 also connects to the return terminal of the electrosurgical generator. As with the other modalities described above, before the device 430 is used in an electrosurgical procedure, the trocar 432 is connected to a patient, such that the patient 447 rests or leans against the patient and provides this the isolation 438 between the patient and the conductive guide 436 is in addition. In addition, the patient return electrode is connected both to the patient and to the return terminal of the electrosurgical generator. In the same way, the conductor 462 extends from the shield 460 and the trocar unit 432 is connected to the return terminal of the generator. Finally, the output terminal of the generator is connected to probe 454 of the electrode. During the electrosurgical procedure, the high frequency electrical current produced by the generator is passed through the probe 454 and is emitted from the tip 456 of the probe. The conductive guide 436 is not available as a resistive return path for the electric current emanating from the P1526 / 98MX tip 456 of probe 454 due to insulation 438 located between conductive guide 436 and the patient. The high frequency electrical current passing through the probe 454 and the dielectric provided by the insulation 458 around the probe results in an electrostatic field that is radiated radially along the entire length of the probe. However, as the electrostatic field emanates from the probe 454, it hits the conductive shield 460. Consequently, the field energy is absorbed by the shield 460 and transported, via the conductor 462, to the return terminal of the generator. Therefore, any conductive elements located around the electrosurgical device 430 will not become capacitively coupled, as long as the electrostatic field emanating from the probe 454 is absorbed by the conductive shield 460. Additionally, any portion of the field which comes into contact with the conductive guide 436 will be absorbed by the guide and drained, via the conductor 462, towards the return terminal of the generator. Therefore, trocar 432 will not become charged as a result of capacitive coupling because all electrostatic energy is drained to the return terminal of the generator. Referring to Figure 8, the device P1526 / 98MX electrosurgical 530 is similar to the electrosurgical device 430 shown in Figure 7, with the exception that the insulating layer 538 also covers the outer surface 544 of the guide 536 and thus encloses the conductive guide 536. From this In this manner, the duct 541 of the trocar is insulated to the flange 543. The portion of the insulating layer 538 within the duct 541 begins at the odistal end 540 of the guide and extends toward the proximal end 539 of the probe. The insulating layer 538 is generally tubular with a tapered end 545 and a flanged end 546 adjacent the flange 543 of the conductive guide 536. Turning now to Figure 9, the electrosurgical device 630 is similar to the electrosurgical device 430 shown in the Figure 7, with the exception of a thermistor regulator 684 temperature sensitive within the insulation 658 that is electrically connected to the shield 660 and extends from the shield to the proximal end 652 of the electrode 654. The regulator 684 has substantially the same configuration that the shield 660. The regulator 684 is made or manufactured of a semiconductor composition that shows a decrease in resistance with an increase in temperature, i.e. it has a coefficient of P1526 / 98MX negative resistance to temperature and, thus, becomes more conductive as the probe heats up during use. Regulator 484 may be constructed of a semiconductor carbon composition made from carbon powder mixed with a phenolic binder that is hot molded or a material having a similar conductivity profile as a function of temperature. Connected along the length of the regulator 684 is the lead 662 which provides a conductive path to release the energy absorbed by the regulator 684. The regulator 684 provides an additional means to absorb the electrostatic energy emanating from the 654 probe. , the regulator 684 becomes more conductive and, in this way, absorbs more electrostatic energy, as the temperature of the probe unit 634 increases due to the increase in the amount of electrical current that passes through the 654 probe. FIGS. 1-9, it is preferred that the electrostatic energy emanating radially from adjacent the proximal end of the probe to the distal end be absorbed by the conductive trocar, the shield or both. Correspondingly, the probe unit should not extend so far from the trocar passageway that the P152S / 98MX electrostatic energy can escape freely through a gap or opening between the conductive trocar and the shield. Therefore, as shown in Figures 1-9, the shield always extends within the conduit provided by the conductive guide portion of the trocar. It will be readily apparent from the above detailed description of the invention and from the illustrations thereof that numerous variations and modifications may be made without deviating from the true spirit and scope of the novel concepts or principles of this invention.

P1526 / 98MX

Claims (23)

1. NOVELTY OF THE INVENTION Having described the present invention, it is considered as a novelty and, therefore, the content of the following CLAIMS is claimed as property: 1. An electrosurgical device comprising: a trocar unit having a conductive guide portion defining an open conduit with a proximal end receiving a probe and an isolated portion defining an open distal end; a probe unit slidably received within the conduit and having a conductive probe with a proximal end and a distal end, an insulating layer surrounding the probe and extending from the distal end, and a conductive shield connected to the layer insulator and surrounding the probe; and a means that connects conductively to the conductive shield in the probe with the conducting guide portion of the trocar.
2. 2. The electrosurgical device according to claim 1, wherein the shield is embedded within the insulating layer.
3. The electrosurgical device according to claim 1, wherein the shield includes a portion Exposed P1526 / 98MX extending from the insulating layer.
4. The electrosurgical device according to claim 1, wherein the conductive guide portion has an outer surface and disposed therein has an insulated portion.
5. The electrosurgical device according to claim 1, wherein the conductive guide portion has a distal end with an isolated portion attached thereto.
6. The electrosurgical device according to claim 1, further including a flange extending radially outward from the isolated portion.
7. The electrosurgical device according to claim 6, further including cords located in the isolated portion and adjacent to the flange.
8. The electrosurgical device according to claim 1, further including a cap attached to the conductive guide portion, the cap having an open bore and the probe extending therethrough.
9. The electrosurgical device according to claim 1, wherein the isolated portion extends into the open conduit.
10. 10. The electrosurgical device according to claim 1, wherein the isolated portion extends toward the open conduit with a etched channel within P1526 / 98MX the isolated portion.
11. The electrosurgical device according to claim 1, wherein the connecting means includes a conductive strip connected to the conductive guide portion.
12. The electrosurgical device according to claim 1, wherein the connecting means includes a conductor connected to the shield and the conductive guide portion.
13. The electrosurgical device according to claim 12, further including a temperature sensitive thermistor controller within the insulating layer and electrically connected to the conductor.
14. 14. An electrosurgical device comprising: a trocar unit having a conductive guide portion defining an open conduit and an isolated portion connected to the conductive guide portion; a probe unit slidably received within the conduit and having a cylindrical conductive probe, an insulating layer surrounds the probe and an integral cylindrical conductive shield to the insulating layer; and means for conductively connecting the conductive shield with the conductive guide portion.
15. 15. The electrosurgical device according to P1526 / 98MX claim 14, wherein the shield is completely embedded within the insulating layer.
16. The electrosurgical device according to claim 14, wherein the shield includes an exposed portion extending from the insulating layer.
17. The electrosurgical device according to claim 14, wherein the conductive guide portion has an external surface disposed therein having an isolated portion.
18. The electrosurgical device according to claim 14, wherein the conductive guide portion has a distal end with an isolated portion connected thereto.
19. 19. The electrosurgical device according to claim 14, which further includes a cap connected to the conductive guide portion, the cap has an open bore and the probe extends therethrough.
20. 20. The electrosurgical device according to claim 14, wherein the isolated portion extends toward the open conduit.
21. The electrochemical device according to claim 14, wherein the connecting means includes a conductive strip connected to the conducting guide portion.
22. 22. The electrosurgical device according to P1526 / 98MX claim 14, wherein the connection means includes a conductor connected to the shield and the conductive guide portion. The electrosurgical device according to claim 22, further including a temperature sensitive regulator within the insulating layer and connected to the conductor. P1526 / 98MX