US20020072739A1 - Methods and devices for radiofrequency electrosurgery - Google Patents

Abstract

An electrically activated surgical device includes a probe body, an active element and a structure for selectively electrically insulating and/or physically isolating the active element from the patient's tissue when the device is in use. The probe body defines an outer surface, a proximal end, a distal end and a window defined within the outer surface near or at the distal end. The active element is electrically connected to a power source and is configured to selectively assume a non-deployed configuration and a variable deployed configuration in which the active element at least partially emerges from the window out of the probe body. The insulating structure selectively insulates the active element from the patient's tissue when the device is inserted therein. In operation, a physician inserts the probe into the tissue, insulates the active element from the tissue (either before, during or after insertion of the probe), energizes the insulated active element using for example, radiofrequency (RF) power from the power source, and only then exposes the energized active element to the tissue. By insulating the active element during the energizing thereof, little or no current applied to the active element is dissipated in the patient's tissue, thus decreasing the time required to energize the active element and enabling lower and safer power levels to be applied to the active element during the energizing thereof.

Description

BACKGROUND OF THE INVENTION
• 1. Field of the Invention[0001]
• The present invention relates primarily to the field of electrosurgery. In particular, the present invention relates to the field of radiofrequency (RF) electrosurgery, including RF cautery, RF dissection, RF fulguration or coagulation, RF desiccation or any other forms of RF-assisted electrosurgery.[0002]
• 2. Description of the Related Art[0003]
• Electrosurgery generally refers to the use of electrically energized surgical devices to operate upon a patient. Common electrosurgical devices include electrocautery devices in which a direct current (DC) is caused to flow through a wire loop. The resistance of the wire causes the loop to heat up, thereby enabling the cauterization of the tissue.[0004]
• More commonly, electrosurgical devices (whether monopolar or bipolar) utilize alternating current (AC) in the range of about 200 kHz to about 3.3 MHz (hereafter “RF”) that is applied to the patient via a RF electrode. Such RF electrosurgical instruments are typically used to dissect (cut), fulgurate (coagulate) or desiccate (dry out) tissue by selectively varying the power and duty cycle of the RF signal applied to the electrode of the electrosurgical instrument. When the RF electrosurgical instrument is monopolar, a large low impedance return (dispersive) electrode is affixed to the patient to provide the current return path to ground. A bipolar RF electrosurgical instrument has two electrodes, the active electrode and the return electrode. The flow of current occurs between these two electrodes, thus obviating the need for a large low impedance return electrode. An insulated RF generator is typically used to energize the RF electrode(s) of the RF electrosurgical instrument.[0005]
• The density of the current delivered to the active electrode may be affected by the impedance (a vector quantity consisting of the tissue's resistance and its reactance) of the tissue. The impedance of the tissue to which the electrodes are exposed has an important effect upon the functioning of RF electrosurgical devices. This is because the tissue becomes an integral part of the circuit comprising the RF generator, the active electrode, the patient's tissue, the return electrode and back to the RF generator to ground or a reference voltage. Therefore, a voltage controlled or limited RF generator (generally providing power between about 10 W and 200 W) is generally used, so that when the impedance of tissue rises, the current delivered to the active electrode safely decreases. The density and impedance of tissue affects the manner in which it is affected by the active electrode. Tissues with higher salt content and body fluids such as blood have a high conductance and therefore, lower impedance. Fatty tissues have a lower fluid content and generally exhibit relatively higher impedance than leaner tissues. Thus, for a given voltage, fatty tissue will dissipate less current than leaner tissue. Highly vascularized tissues, on the other hand, have very low impedance and tend to conduct current more efficiently than less vascularized tissues. Therefore, to achieve the same tissue effect, current must be applied to a RF electrode in contact with highly vascularized tissue for a longer period of time than would be the case if the RF electrode were in contact with comparatively less vascularized tissue. Alternatively, the initial power applied to the RF electrode may need to be momentarily increased to achieve the same tissue effect in a fixed period of time.[0006]
• FIGS.[0007]1-3 show a RFexcisional device100 that includes aprobe102, thedistal end108 of which includes a conductive ribbon orwire loop106 configured to bow out of and back into awindow104 defined within theprobe102. Theloop106 is connected to a RF power supply (not shown). Theloop106 is energized with RF energy and theprobe102 is rotated as shown at112 with theloop106 in an extended or deployed configuration, as shown in FIG. 3. As theprobe102 is rotated, a volume of revolution of tissue is cut by the RF-energizedloop106.
• However, when the[0008]loop106 is in contact with the tissue to be cut, the physician often must wait a relatively long period of time (several seconds or longer) between initial application of the RF power to theloop106 and the time at which the current density within theloop106 is high enough to cut (vaporize) the tissue. This is because the relatively low impedance of the interface between theloop106 and the patient's tissue shown at114 in FIG. 5 dissipates a substantial amount of the current delivered to theloop106. Highly vascularized tissue may also increase the current conduction (symbolized by the arrows emanating from theloop106 in FIG. 5) away from theloop106 and further delay the time at which theRF loop106 is able to cut through thetissue114. Indeed, until thetissue114 chars and the impedance thereof increases, the current density within theloop106 may not quickly reach that level at which theenergized loop106 is therapeutically effective.
• One solution to this problem is to initially increase or surge the power delivered to the[0009]loop106 to decrease the time required for the current density therein to reach the desired level. However, this is a less than optimal solution, as such an initial power surge may cause pain, excessive charring of thetissue114 at the initial cut site, and may present a safety risk to the patient, who is better served by maintaining power levels as low as practicable to achieve the objective of the procedure. Such initial power surges, moreover, require specialized RF generators that are configured to deliver such surges safely and on demand.
• What are needed, therefore, are improved methods and RF electrosurgical devices that do not suffer from the aforementioned disadvantages. More particularly, what are needed are RF electrosurgical devices that energize quickly, cut more efficiently and less painfully, reduce tissue charring at the initial cut site, and do not require an initial power surge from a specialized RF generator.[0010]
SUMMARY OF THE INVENTION
• It is, therefore, an object of the present invention to provide methods and RF electrosurgical instruments that do not suffer from the aforementioned disadvantages. It is also an object of the present invention to provide RF electrosurgical instruments that energize quickly, are safer, cut more efficiently and less painfully, reduce tissue charring at the initial cut site and do not require an initial power surge from a specialized RF generator.[0011]
• In accordance with the above-described objects and those that will be mentioned and will become apparent below, an electrosurgical device according to an embodiment of the present invention, includes a body, the body defining an outer surface, a proximal end, a distal end and a window defined within the outer surface; an electrically insulating layer and an active element, the active element being adapted to electrically connect to a power source and configured to selectively assume a non-deployed configuration in which the insulating layer electrically insulates the active element from a patient's tissue when the device is in use and a variable deployed configuration in which the active element at least partially emerges from the window out of the body to make contact with the patient's tissue.[0012]
• The active element may include one of a ribbon and wire, said one of ribbon and wire being adapted to selectively bow out of the window when transitioning from the non-deployed configuration to the deployed configuration. A tissue collection means may be attached thereto or trail behind the active element, as disclosed in co-pending and commonly assigned U.S. patent application Ser. No. 09/565,611 filed on May 4, 2000 and/or commonly assigned U.S. Pat. No. 6,022,362 filed on Sept. 3, 1998, the disclosure of each being incorporated herein by reference in its entirety.[0013]
• The active element may be configured to carry tissue ablation, dissection, fulguration, cautery, desiccation, hyperthermia or hypothermia, for example. The thickness of the insulating layer may be selected within a range of about 0.1 mm to about 5 mm, for example. The power source may include a RF power source. The window may be disposed near the distal end of the body or at the distal end thereof. The active element may be ring-shaped and may include a trailing tissue collection means attached thereto adapted to collect tissue cut by the ring-shaped active element. The insulating layer may include an electrically insulating sliding door mounted within the body, the sliding door being configured to selectively cover at least a portion of the window. The sliding door may be configured to slide between a variable first position in which at least a portion of the active element is exposed to the patient's tissue through the window and a second position in which the sliding door electrically insulates the active element within the body from the patient's tissue. The insulating layer may include a layer of air and the window may be configured to maintain the layer in the non-deployed configuration. The insulating layer may include an electrically insulating outer sleeve configured to selectively slide over the outer surface of the body, the outer sleeve being configured to at least partially cover the active element to electrically insulate the active element from the patient's tissue and uncover the active element to expose the active element to the patient's tissue. The insulating layer further may include an electrically insulating sheath disposed around at least a portion of the device body, the insulating sheath defining a cutaway portion aligned with the window and defining one or more raised portions configured to prevent the patient's tissue from prolapsing into the window when the active element is in its non-deployed configuration. The insulating layer may include an insulating sleeve disposed at least partially around the active element, the insulating sleeve being configured to controllably slide over the active element to selectively electrically insulate the active element from the patient's tissue and expose the active element thereto when the device is in use. The body may be shaped as a non-coring needle. The insulating layer may include a layer of air and the device body may define one or more raised portions adjacent the window, the raised portion(s) maintaining the layer of air between the active element and the patient's tissue when the active element is in its non-deployed state. Suction means may be included within the body for controllably removing fluids from the operative site within the patient's tissue.[0014]
• The present invention may also be viewed as a method of treating tissue using a probe, the probe including an active element that may be extendable out of and retractable back into a window defined in the probe, the active element being electrically connected to a power source, comprising the steps of: inserting the probe into the tissue; electrically insulating the active element from the tissue; energizing the active element using power from the power source, and exposing the energized active element to the tissue.[0015]
• The power source may be adapted to supply RF power to the active element. The insulating step may include a step of maintaining an electrically insulating layer between the active element and the tissue. The probe further may include an electrically insulating sliding door and the insulating step may include a step of sliding the door across the window. The method may further comprise the step of inducing hyperthermia or hypothermia and necrosis in the tissue exposed to the active element. The probe further may include an electrically insulating outer sleeve adapted to slide over an outer surface of the probe and the insulating step may include a step of sliding the outer sleeve over the window. The probe further may include an insulating sheath around at least a portion of the probe body, the insulating sheath including at least one raised portion adjacent the window and the insulating step may include a step of maintaining the active element retracted within the window. The insulating step may include a step of maintaining the active element retracted within the window. The probe further may include an insulating sleeve adapted to slide over the active element and the insulating step may include a step of sliding the insulating sleeve over the active element. The insulating step may include a step of creating or maintaining a layer of air between the active element and the tissue. The probe further may include an inflatable balloon disposed adjacent the window, and the insulating step further may include a step of inflating the balloon to create a layer of air between the tissue and the active element.[0016]
• The present invention is also an electrosurgical device, comprising a device body, the body defining a proximal end and a distal end; an active element coupled to the body, the active element being adapted to be controllably energized from a power source; and means for selectively electrically insulating and exposing the active element from and to a patient's tissue when the device is in use.[0017]
• The active element may be configured to selectively assume a non-deployed configuration in which the active element is recessed within the body and a variable deployed configuration in which the active element at least partially emerges from the body. The active element may be configured to carry out tissue ablation, dissection, fulguration, cautery, desiccation, hyperthermia and/or hypothermia, for example. The active element may be configured to be energized by a RF power source, for example. The device body may define a window disposed near the distal end of the body, and the active element may be configured to selectively retract into and extend from the window. A window may be defined within the body and the insulating means may include an electrically insulating sliding door mounted within the body, the sliding door being configured to selectively cover at least a portion of the window. The sliding door may be configured to slide between a variable first position in which at least a portion of the active element is exposed through the window and a second position in which the sliding door electrically insulates the active element from the patient's tissue. The insulating means may be integral with the window and the window may be configured to prevent tissue from prolapsing therein and making physical and/or electrical contact with the active element when the active element is in a non-deployed configuration. The insulating means may include an electrically insulating outer sleeve configured to selectively slide over the outer surface of the body, the outer sleeve being configured to at least partially cover the active element and electrically insulate the active element from the patient's tissue when the device is in use and the active element is in a non-deployed configuration. The insulating means may include an electrically insulating sleeve disposed at least partially around the active element, the insulating sleeve being configured to controllably slide over the active element to selectively electrically insulate the active element from the patient's tissue and expose the active element thereto when the device is in use. The insulating means may be integral with the body and may define one or more raised portions, the raised portion(s) being configured to prevent tissue from making physical and/or electrical contact with the active element until the active element is deployed. The insulating means may include an electrically insulating sheath disposed over the body, the insulating sheath defining at least one raised portion configured to prevent the patient's tissue from coming into contact with the active element until the active element is deployed. The active element may be shaped as a ring and the insulating means may be integral with the distal end of the body, the ring-shaped active element being configured to be recessed away from the distal end of the body until fully energized.[0018]
• The present invention is also an electrosurgical device adapted for insertion into tissue, comprising: a device body; a RF energizable active element disposed within the device body, and an insulating structure. The device body and/or the insulating structure may be configured to insulate the active element from the tissue until the active element is sufficiently energized to be therapeutically effective when the active element is brought into contact with the tissue.[0019]
BRIEF DESCRIPTION OF THE DRAWINGS
• FIG. 1 is a top view of the distal end of an expandable loop excisional device.[0020]
• FIG. 2 is a side view of the distal end of the excisional device of FIG. 1, in which the loop is in its non-extended (non-deployed) configuration.[0021]
• FIG. 3 is a side view of the distal end of the excisional device of FIG. 1, in which the loop is in its extended (deployed) configuration.[0022]
• FIG. 4 is a cross-sectional view of the excisional device of FIG. 2, taken along cross-sectional lines AA′.[0023]
• FIG. 5 shows the excisional device of FIG. 4 in which the loop is in contact with tissue, to illustrate the current dissipation occurring at the loop-tissue interface.[0024]
• FIG. 6 shows an embodiment of a RF electrosurgical device, according to an embodiment of the present invention.[0025]
• FIG. 7 shows the distal end of the RF electrosurgical device of FIG. 6, in which the active element thereof is in its non-extended (non-deployed) configuration.[0026]
• FIG. 8 shows the distal end of the RF electrosurgical device of FIG. 7, in which the active element thereof is in its extended (deployed) configuration.[0027]
• FIG. 9 is a cross-sectional view of the excisional device of FIG. 7, taken along cross-sectional lines BB′.[0028]
• FIG. 10 shows the excisional device of FIG. 9 and illustrates the absence of active element-tissue interface when the RF electrosurgical device of the present invention is initially inserted in tissue and RF power applied to the active element.[0029]
• FIG. 11 shows another embodiment of a RF electrosurgical device, according to the present invention.[0030]
• FIG. 12 shows the distal end of the RF electrosurgical device of FIG. 11, in which the active element thereof is in a non-extended (non-deployed configuration).[0031]
• FIG. 13A shows the distal end of the RF electrosurgical device of FIG. 11, in which the active element thereof is in a first illustrative extended (deployed configuration).[0032]
• FIG. 13B shows the distal end of the RF electrosurgical device of FIG. 11, in which the active element thereof is in a second illustrative extended (deployed configuration).[0033]
• FIG. 14 is a cross-sectional view of the excisional device of FIG. 12, taken along cross-sectional lines CC′. FIG. 15 shows the excisional device of FIG. 14 and illustrates the absence of active element-tissue interface when the RF electrosurgical device of the present invention is initially inserted in tissue and RF power is applied to the active element.[0034]
• FIG. 16 is a top view of another embodiment of an electrosurgical device according to the present invention.[0035]
• FIG. 17 shows a side view of the distal end of the electrosurgical device of FIG. 16, in which the active element thereof is in its non-deployed configuration.[0036]
• FIG. 18 shows the electrosurgical device of FIG. 17, in which the active element thereof is in its deployed configuration.[0037]
• FIG. 19 shows a side view of another embodiment of an electrosurgical device according to the present invention, in which the active element thereof is in its non-deployed configuration.[0038]
• FIG. 20 shows the electrosurgical device of FIG. 19, in which the active element thereof is in its deployed configuration.[0039]
• FIG. 21 is a top view of the distal end of an electrosurgical device according to a still further embodiment of the present invention.[0040]
• FIG. 22A is a side view of the device of FIG. 21, in which the inflatable balloon(s) thereof has (have) been inflated to create an insulating layer between the active element and the patient's tissue.[0041]
• FIG. 22B is a front view of the device of FIG. 22A, in which the balloons are in their inflated configuration.[0042]
• FIG. 23 is a side view of the device of FIG. 21, after deflation of the balloon(s) and deployment of the active element.[0043]
• FIG. 24 shows a top view of the distal end of an electrosurgical device according to another embodiment of the present invention.[0044]
• FIG. 25 shows a side view of the device of FIG. 24.[0045]
• FIG. 26 shows the device of FIG. 25, after the outer sleeve thereof has been slid away from the window from which the active element is deployed.[0046]
• FIG. 27 is a flowchart of a method for carrying out an electrosurgical procedure according to an embodiment of the present invention.[0047]
• FIG. 28 is a top view of an electrosurgical device, according to another embodiment of the present invention.[0048]
• FIG. 29 is a side view of the distal portion of the device of FIG. 28, showing the active element thereof in its non-extended and sheathed state.[0049]
• FIG. 30 is a side view of the distal portion of the device of claim 28, showing the active element thereof in its extended and unsheathed state.[0050]
• FIG. 31 is a cross-sectional view of the electrosurgical device of FIG. 29, taken along cross-sectional lines DD′.[0051]
• FIG. 32 is a top view of an electrosurgical device, according to another embodiment of the present invention.[0052]
• FIG. 33 is a side view of the distal portion of the device of FIG. 32.[0053]
• FIG. 34 is a side view of the distal portion of the device of FIG. 32, in which the active element is in its extended state.[0054]
• FIG. 35 is a cross-sectional view of the electrosurgical device of FIG. 33, taken along cross-sectional lines EE′.[0055]
• FIG. 36 shows a cross-sectional view of another embodiment of the electrosurgical device of FIG. 33, taken along cross sectional lines EE′[0056]
• FIG. 37 shows another electrosurgical device, according to yet another embodiment of the present invention.[0057]
• FIG. 38 is a perspective side view of the distal portion of the electrosurgical device of FIG. 37, in which the electrosurgical ring is in its non-extended state.[0058]
• FIG. 39 is a perspective side view of the distal portion of the electrosurgical device of FIG. 37, in which the electrosurgical ring is in its extended state.[0059]
DESCRIPTION OF THE INVENTION
• FIGS.[0060]6-10 show an embodiment of a RFelectrosurgical device200, according to the present invention. As shown therein, thedevice200 includes aprobe body202, theprobe body202 defining an outer surface, aproximal end230, adistal end208 and a window204 (shown in dashed lines in FIGS. 7 and 8) defined within the outer surface near thedistal end208. Theprobe200 includes anactive element206. Theactive element206 may include, for example one or more wires and/or loops, or any other therapeutically effective RF element effective to cut, dissect, fulgurate and/or desiccate tissue (for example) using RF power. Theactive element206 may be electrically connected to a power source, such as theRF power source240. Adistal RF element210 may also be mounted to thedistal end208 of theprobe body202, to facilitate penetration of theprobe200 into the patient's tissue. Thedistal RF element210 may also be independently electrically connected to theRF power source240. According to the present invention, theactive element206 may be configured to selectively assume a non-deployed configuration (FIG. 7) and a variable deployed configuration (FIG. 8). In the variable deployed configuration (FIG. 8), theactive element206 at least partially emerges from thewindow204 out of theprobe body202. The deployment of theactive element206 may be controlled by the physician by means of anactuator236, such as the thumb wheel shown in FIG. 6 or other actuation means. By turning theactuator236 with his or her thumb, the physician causes theactive element206 to slide within aguide326 defined within theprobe202. As the distal end of theactive element206 is attached to thedistal end208 of theprobe200, theactive element206 bows out of thewindow204, the degree of bowing and deployment out of thewindow204 being controlled by theactuator236.
• In the non-deployed configuration, the[0061]active element206 is recessed within theprobe body202 to define an insulating layer212 (a layer of air, for example) with respect to the outer surface of theprobe body202. The recessedactive element206 and/or the presence of the insulatinglayer212 enables theactive element206 to be energized without contacting the patient's tissue. Indeed, by avoiding contact with the patient's tissue during the energizing of theactive element206, the current delivered to theactive element206 is not dissipated by the patient's tissue that would otherwise be in contact therewith but for the presence of the insulatinglayer212. According to the present invention, after theactive element206 is energized, theactive element206 may be deployed to (for example) cut, ablate or coagulate (depending upon the application) the patient's tissue without the physician having to wait for the tissue impedance to rise sufficiently (while the patient's tissue heats up and/or chars) to enable the current density within theactive element206 to reach the desired level for the procedure to be carried out. FIGS. 9 and 10 show a cross-sectional view of theprobe200, taken along the cross-sectional lines BB′of FIG. 7. As shown therein, to electrically insulate theactive element206 from the patient's tissue (reference214 in FIG. 10), thewindow204 defined within theprobe body202 may be shaped and/or dimensioned so as to prevent thetissue214 through which theprobe200 is inserted from prolapsing therein. As shown, thewindow204 is configured to define an electrically insulatinglayer212 between theactive element206 and the patient'stissue214 when theactive element206 is in its non-deployed (retracted) configuration. Toward that end, thewindow204 may define a steep aspect ratio, in which the depth of thewindow204 is greater than its width.
• FIGS.[0062]11-15 show aprobe300 according to another embodiment of the present invention. Reference numerals that are identical to those shown in FIGS.6-10 denote identical structures. For the sake of brevity, the description of those identical structures will not be explicitly repeated here. In FIGS.11-15, the insulating layer that electrically insulates theactive element206 from the patient'stissue214 includes a slidingdoor216 disposed within theprobe body202. The slidingdoor216 may be made of an electrical insulator or other substantially non-conductive material or materials. The slidingdoor216 is configured to selectively cover at least a portion of thewindow204 to electrically insulate theactive element206 of thedevice300 from the patient'stissue214 until theactive element206 is fully energized and/or until the physician chooses to expose theactive element206 to the patient'stissue214. The physician, according to the present invention, may cause the slidingdoor216 to slide and expose theactive element206 by means of a sliding door actuator such as a manual thumb wheel, as shown at356. It is understood that other means of acting upon the slidingdoor216 and/oractive element206 may be employed, as the present invention is not limited to thumb wheel actuators, as shown at356 and236. According to the present invention, the slidingdoor216 is configured to slide between a variable first position in which at least a portion of the active element is exposed through the window (as shown in FIGS. 13A and 13B) and a second position (shown in FIGS. 11, 12,14 and15) in which the slidingdoor216 insulates theactive element206 within theprobe body202. As shown in FIGS. 13A and 13B, the slidingdoor216 may be caused to expose a selectable portion of theactive element206 to the patient'stissue214. In so doing, the slidingdoor216 may affect the shape of the deployed active element: if the slidingdoor216 is fully or near fully retracted as shown in FIG. 13A, a greater portion of theactive element206 may emerge from thewindow204 than is the case wherein the slidingdoor216 is only partially retracted and only exposes a portion of thewindow204, as shown in FIG. 13B. This may enable the physician to control the extent of deployment and the shape of the extendedactive element206. FIGS. 14 and 15 show the slidingdoor216 as it covers thewindow204, thereby electrically insulating theactive element206 from the patient'stissue214. The slidingdoor216 may be guided within theprobe body202 by means of, for example, internal guides or rails218. Using this configuration, the physician may apply RF power to theactive element206 and begin the intended RF procedure (cutting, ablating, coagulating, etc.) sooner than would otherwise be the case if the de-energized active element were energized while in contact with the patient'stissue214. The layer ofair213 between theactive element206 and the slidingdoor216 may be reduced or eliminated altogether, as the slidingdoor216 electrically insulates and physically isolates theactive element206 from the patient'stissue214. The slidingdoor216, for that purpose, is preferably formed of non-conductive material, such as a non-conductive plastic or ceramic, for example.
• FIGS.[0063]16-18 show another embodiment of the present invention. As shown therein, theelectrosurgical device400 includes aproximal end260, adistal end208, aprobe body202, anactive element actuator236 and a slidingdoor actuator356, as described above. The distal tip of the probe body defines anopening290 that is aligned with aninternal lumen282 defined within theprobe body202. The exemplaryactive element218 shown in FIGS.16-18 includes an elongated conductive stem that is distally terminated by a conductive bulb. However, any electrically active element may be used in conjunction with or in place of the active element depicted in FIGS.16-18. Theactive element218 may be electrically coupled to theRF power source240. The bulb may be used, for example, to induce hyperthermia and/or necrosis in thetissue214 with which it comes into contact. In that case, the duty cycle of the RF current applied to theactive element218 may be adjusted to be, for example, 50%-25%, so as to induce substantial heating in thetissue214 in contact with theactive element218. In this embodiment, the insulating layer separating theactive element218 from the patient'stissue214 when theactive element206 is in its non-deployed configuration may include a sliding and electrically insulatingdoor220 mounted within theprobe body202. The slidingdoor220 may be configured to slide axially in the distal and proximal directions (away from and toward the physician, respectively, when thedevice400 is in use) when the slidingdoor actuator356 is actuated. The distal end of the slidingdoor220 may be advantageously configured to cover (see FIG. 17) theopening290 during insertion of thedevice400 into the patient'stissue214 and during the energizing of theactive element218. After thedevice400 has been inserted up to the targeted site within the patient'stissue214 and theactive element218 has been energized, the physician may actuate the slidingdoor actuator356 to retract the slidingdoor220 away from theopening290, in theproximal direction294. Thereafter, the energizedactive element218 may be advanced in thedistal direction296 into the target area of the patient'stissue214 to begin treatment thereof, as shown in FIG. 18. Alternatively, the slidingdoor220 may be retracted before theactive element218 is energized. Thereafter, theactive element218 may be energized without dissipating current into the surroundingtissue214, as theactive element218 is still recessed and electrically insulated from the patient's tissue by anair layer215. The shape and/or size of theopening290 and/or the thickness of theair layer215 may also prevent the patient'stissue214 from prolapsing into theopening290, thereby further insulating theactive element218. As shown in FIGS. 16 and 17, theactive element218 is fully insulated from the patient'stissue214 by the slidingdoor220 until theactive element218 is appropriately energized, thereby preventing any disadvantageous dissipation of RF current into thetissue214 upon the application of RF current to theactive element218.
• FIGS.[0064]19-20 show a still further embodiment of the present invention. As shown therein, theelectrosurgical device500 includes aprobe body202 defining aproximal end230, adistal end208 and aninternal lumen217. Theproximal end230 includes anactive element actuator236, as described above. Anactive element218 is configured to slide within theinternal lumen217, as controlled by theactive element actuator236. Most any RF active element may be used within theelectrosurgical device500. For simplicity's sake, however, the stem and bulbactive element218 of FIGS.16-18 is again used here, it being understood that this embodiment is not limited thereby. As shown in FIGS.19-20, thedistal end208 of theprobe body202 may be shaped as a non-coring needle. As shown in FIG. 19, theactive element218 may be recessed within theinternal lumen217 of the probe body to define an electrically insulatinglayer219. Thelayer219 may also physically isolate theactive element218 from the patient's tissue when the active element is in its non-deployed state, as shown in FIG. 19. When thedevice500 is properly positioned within the patient (as verified, for example, through the use of ultrasound) and theactive element218 energized, theactive element actuator236 may be used to advance the energizedactive element218 in thedistal direction296 until theactive element218 emerges from thedistal opening292 and extends to the desired length, as shown in FIG. 20. The insulating layer219 (FIG. 19) between theactive element218 and theopening294 defined in the distal end of the probe body202 (and/or the tissue214) prevents any of the RF current applied to theactive element218 from dissipating into the patient'stissue214 during the energizing of theactive element218.
• Some or all of the through[0065]holes938 may be utilized for the delivery of a fluid to the patient during the procedure, such as antibiotic agents, analgesic agents or most any pharmaceutical agent. Such agents may be administered to the patient from theport942. Alternatively, theport942 may be coupled to suction and some or all of the throughholes938 may be utilized to suction out the operative site of smoke, blood or other bodily fluids during or after the operative procedure. Alternatively still, more than oneport942 may be provided in theproximal portion902 and more than oneinternal lumen940 may be defined along the length of theprobe500. The additional lumen may be in fluid communication with selected throughholes938. By this structure, both delivery of a pharmaceutical agent and suctioning may be provided within asingle probe500. It is to be understood that any of the devices according to the present invention may incorporate all or a portion of the structures referenced by938,940 and942 or like structures to provide suctioning and/or fluid delivery functionality.
• FIGS.[0066]21-23 shows the distal portion of a still further embodiment of the present invention. As shown therein, thedevice600 defines adistal end208, awindow204 and anactive element206, as described above. Thedevice600 also includes one or moreinflatable balloons602. As best shown in FIG. 21, at least onesuch balloon602 may advantageously be disposed in close proximity to and may be co-extensive with thewindow204 from which theactive element206 emerges and deploys. FIG. 22A shows thedevice600 in a configuration wherein theactive element206 is in its non-deployed configuration and theballoons602 are in their inflated configuration. For example, theballoons602 may be inflated with CO₂(for example) from a CO₂reservoir (not shown) located within or without thedevice600. FIG. 22B shows a front view of the device of FIG. 22A and illustrates the insulatinglayer212 between theactive element206 and thetissue214 created by the inflation of theballoons602. Finally, FIG. 23 shows a side view of thedevice600 in a configuration wherein theactive element206 is deployed and theballoons602 deflated, rendering them (preferably) flush or substantially flush with the outer surface of thedevice600. In operation, thedevice600 may be advanced through the patient'stissue214 until the target area is reached. The balloon or balloons602 may then be inflated, thereby creating the insulatinglayer212 between theactive element206 and thetissue214. Theactive element206 may then be energized with RF current from a RF power supply, such as shown at240 in FIG. 16, for example. After energizing theactive element206, theballoon602 orballoons602 may be deflated and the active element deployed, as described above. Once again, initially electrically insulating theactive element206 from thetissue214 advantageously prevents current from dissipating into thetissue214 during the energizing of theactive element206. Thereafter, theactive element206 may be brought into contact with the patient'stissue214 when theactive element206 has been energized to a therapeutically effective level.
• FIGS.[0067]24-26 show the distal portion of a still further embodiment of the present invention. As shown therein, theelectrosurgical device700 includes aprobe body202, awindow204 defined within theprobe body202 near thedistal end208 thereof, and anactive element206 within thewindow204, as previously described. To electrically insulate theactive element206 during the energizing thereof using a RF power source (such as shown at240 in FIG. 16), an electrically insulatingouter sleeve702 is fitted over theprobe body202. Theouter sleeve702 is configured to slide over and/or against the outer surface of theprobe body202 in the proximal and axial directions. Upon energizing theactive element206, theouter sleeve702 may advantageously be maintained in a position wherein it preventstissue214 from coming into contact with theactive element206. After theactive element206 is energized, the physician may retract theouter sleeve702 by sliding it in theproximal direction294. By fully retracting theouter sleeve702, the physician may expose the entireactive element206 to thetissue214. However, by only partially retracting theouter sleeve702, as shown at702A, the physician may advantageously change the extent of deployment and/or shape of the active element, as shown at206A.
• It should also be noted that the active element in FIGS.[0068]6-26 may also include a device to cause hypothermia and subsequent necrosis in the patient's tissue; i.e., to freeze the patient's tissue in contact with the active element. Indeed, by energizing such an active device while it is electrically insulated and/or physically isolated from the patient'stissue214, the temperature of the active element will drop to the intended low temperature faster than if the active element were initially in contact with the patient'stissue214, especially if the tissue is highly vascular (and thus able to transport heat efficiently).
• FIG. 27 is a flowchart of a method of carrying out an electrosurgical procedure, according to the present invention. Step SI calls for the insertion of a RF electrosurgical device, such as shown in FIGS.[0069]6-26, into the patient's tissue. Advantageously, ultrasound (or any other radiological) guidance may be employed to guide the device to the targeted site within the patient's tissue. Step S2 calls for electrically insulating (and/or physically isolating) the active element (such as shown at206,218) of the RF device from the surrounding tissue. The insulating step S2 may be carried out either before, during or after step S1, but should be carried out before step S3 that is, before energizing the active element. Insulating and/or electrically isolating the active element may entail ensuring the presence of an insulating layer (preferably about 0.1 mm to about 5 mm in thickness) by maintaining the active element recessed within the probe body, in its retracted, non-deployed configuration and/or sliding a sliding door (216,220) over the active element, inflating a balloon or balloons602 and/or maintaining anouter sleeve702 over the active element. Alternatively, any means of creating an insulatinglayer212 and/or insulating the active element from the surrounding tissue during the energizing thereof may be employed within the scope of the present invention. Step S4 calls for exposing at least a portion of the energized active element to the patient's tissue and step S5 calls for carrying out the intended procedure, such as cutting, ablation, coagulation, etc.
• FIGS.[0070]28-31 represent different views of anelectrosurgical device800, according to another embodiment of the present invention. Considering now FIGS.28-31 collectively, thedevice800 includes aproximal end260, adistal end208 and may include adistal RF element210, as described above. Thedevice800 includes anactive element206, which may include one or more wires and/or loops, or any other therapeutically effective RF element effective to cut, dissect, fulgurate, induce hyper or hypothermia (from a different power source) and/or to desiccate tissue using RF power. Theactive element206 may be electrically coupled to a power source, such as theRF power source240. The embodiment illustrated in FIGS.28-31 is configured to selectively electrically insulate and/or physically isolate theactive element206 from the patient'stissue214. Indeed, theactive element206 may be selectively insulated and/or isolated from the patient'stissue214 by means of aninsulating sleeve802 that is configured to at least partially surround and at least partially cover theactive element206, as most clearly shown in the cross-sectional view of FIG. 31. The insulatingsleeve802 is further configured to slide over theactive element206 and to loosely cover theelement206, as shown in FIG. 29. When theactive element206 is fully energized, thesleeve802 may be retracted in the proximal direction (toward the physician) using an appropriate actuator such as the insulatingsleeve actuator357 for example, thereby exposing theactive element206 to the patient's tissue and enabling deployment of theactive element206, as shown in FIG. 30. The insulating andretractable sleeve802 may include or be formed of a flexible material, such as a silicone elastomer (such as polydimethyl siloxane, for example). During the procedure, theactive element206 may be retracted within thewindow204 defined within the probe body and the insulatingsleeve802 advanced in the distal direction (i.e., toward the distal end208). This may enable the operator to remove any char that may have adhered to theactive element206 without, however, removing theprobe800 from the patient.
• FIGS.[0071]32-36 show a still further embodiment of the present invention, in which theactive element206 of theelectrosurgical device900 is initially electrically insulated from the patient'stissue214 not by an insulating sleeve, but by an external sheath902 (FIGS.32-35) or by the configuration or topology of the probe body200 (FIG. 36). Considering FIGS.32-35 collectively, this embodiment of theelectrosurgical device900 of the present invention includes aprobe body202 defining aproximal end260 and adistal end208. Thedevice900 includes anactive element206, which may include one or more wires and/or loops, or any other therapeutically effective element effective to cut, dissect, fulgurate, or induce hyper or hypothermia. Theactive element206 may be electrically coupled to a power source, such as theRF power source240. Thedevice900 may also include adistal RF element210. As shown, thedevice900 may also include an insulatingsheath902 disposed over at least a portion of theprobe body202. According to the present invention, thesheath902 may include acutaway portion910 that may be aligned with and expose theunderlying window204 defined within theprobe body202. As shown in FIG. 33, when theactive element206 is in its retracted position, the insulatingsheath902 electrically insulates theactive element206 from the patient'stissue214, whereas thesheath902 does not interfere with theactive element206 when theactive element206 is in its extended configuration, as shown in FIG. 34. Suction may be advantageously employed here to clear the operative site from electrically conductive bodily fluids and/or smoke. As shown most clearly in the cross-sectional view of FIG. 35, thesheath902 may have a generally circular cross section, and may include one or more raisedportions906 adjacent to thewindow204 and substantially aligned therewith. The raised portion(s)906 enable theactive element206, in its retracted position, to be electrically insulated from the patient'stissue214 by an insulatinglayer904 measuring about 0.1 mm to about 5 mm in thickness, for example. In this manner, theactive element206 may be fully energized by theRF power source240 before being brought into contact with the patient's tissue, with the accompanying advantages discussed above. Thesheath902 may cover all or only a portion of theprobe body202.
• FIG. 36 shows another embodiment of the present invention, wherein the probe body alone is shaped so as to insulate the[0072]active element206 from the patient'stissue214 until theactive element206 is fully energized. As shown therein, theprobe body202 may include one or more locally raisedportions907 adjacent to thewindow204 from which theactive element206 extends. The raised portion(s)907 (raised about 0.5 mm to about 5 mm away from the outer surface of the probe body, for example) may be defined along the long sides of thewindow204 or around the entire perimeter thereof. The raised portion(s)907 need not be continuous, as long as they serve to effectively electrically insulate thetissue214 from theactive element206 until theactive element206 is fully energized. As shown in FIG. 36, thetissue214 is separated from the non-extendedactive element206 by the insulating (air)layer904 by the raisedportions907 of theprobe body202 which prevent thetissue214 from prolapsing into thewindow204 and coming into contact with theactive element206 until the physician chooses to extend theactive element206 and begin cutting the patient'stissue214.
• Any geometry of the[0073]sheath902 and/or probebody202 and/or active element that forms an insulating layer between the active element and the patient's tissue when the active element is in its non-deployed state falls into the scope of the present invention. Likewise, any structure that prevents thetissue214 from prolapsing into thewindow204 or that generally prevents theactive element206 from coming into contact with the tissue until theactive element206 is fully energized also falls within the scope of the present invention.
• The present invention, moreover, is not limited to any particular active element. Indeed, although the embodiments of the present invention are herein illustrated with an extendible loop active element, the present invention is not so limited. An important aspect of the present invention is the electrical insulation and/or physical isolation of the active element of an electrosurgical device from the patient's tissue until the active element is fully energized. This aspect is again illustrated in FIGS.[0074]37-39, in which the active element is shown as having a ring shape and the probe body little more than a hollow cannula. Theelectrosurgical device1000 shown in FIGS.37-39 includes aprobe body1002 that defines aproximal end260 and adistal end1012. Anactive element actuator236 is configured to extend and retract a ring-shapedRF element1006 from and back into thedistal end1012 of theprobe body1002. The ring-shapedactive element1006 is electrically coupled to theRF power source240 and mechanically coupled to theactuator236 by means ofrod1004 or by other means known to those of skill in this art. FIG. 38 shows thedistal end1012 of theprobe body1002 and the ring-shapedactive element1006 in its retracted position. In accordance with the present invention, theactive element1006 is electrically insulated from the patient's tissue (not shown) by virtue of its recessed position (recessed by a distance of about 0.1 mm to about 5 mm, for example) within theprobe body1002. Suction may be employed to maintain the recess clear of bodily fluids. This enables the physician to insure that theactive element1006 is fully energized before theactive element1006 is deployed or extended (see FIG. 39) out of thedistal end1012 of theprobe body1002 and comes into contact with the patient's tissue. As shown in FIG. 39, a mesh orother membrane1010 may be attached to and trail theactive element1006 to collect tissue cut by theactive RF element1006. This mesh may be expandable, to enable the collection of a relatively large mass of tissue. Likewise, the ring-shapedactive element1006 may itself be expandable in diameter or deformed in shape so as to enable collection of large or irregularly shaped lesions or specimens.
• While the foregoing detailed description has described preferred embodiments of the present invention, it is to be understood that the above description is illustrative only and not limiting of the disclosed invention. Those of skill in this art will recognize other alternative embodiments and all such embodiments are deemed to fall within the scope of the present invention. Thus, the present invention should be limited only by the claims as set forth below.[0075]

Claims (42)

What is claimed is:

1. An electrosurgical device, comprising:

a body, the body defining an outer surface, a proximal end, a distal end and a window defined within the outer surface;

an electrically insulating layer, and

an active element, the active element being adapted to electrically connect to a power source and configured to selectively assume a non-deployed configuration in which the insulating layer electrically insulates the active element from a patient's tissue when the device is in use and a variable deployed configuration in which the active element at least partially emerges from the window out of the body to make contact with the patient's tissue.

2. The device ofclaim 1, wherein the active element includes one of a ribbon and wire, said one of ribbon and wire being adapted to selectively bow out of the window when transitioning from the non-deployed configuration to the deployed configuration.

3. The device ofclaim 1, wherein the active element is configured to carry out at least one of tissue ablation, dissection, fulguration, cautery, desiccation, hyperthermia and hypothermia.

4. The device ofclaim 1, wherein a thickness of the insulating layer is selected within a range of about 0.1 mm to about 5 mm.

5. The device ofclaim 1, wherein the power source includes an RF power source.

6. The device ofclaim 1, wherein the window is disposed one of near the distal end of the body and at the distal end thereof.

7. The device ofclaim 6, wherein the active element is ring-shaped and includes a trailing tissue collection means attached thereto adapted to collect tissue cut by the ring-shaped active element.

8. The device ofclaim 6, wherein the insulating layer includes an electrically insulating sliding door mounted within the body, the sliding door being configured to selectively cover at least a portion of the window.

9. The device ofclaim 8, wherein the sliding door is configured to slide between a variable first position in which at least a portion of the active element is exposed to the patient's tissue through the window and a second position in which the sliding door electrically insulates the active element within the body from the patient's tissue.

10. The device ofclaim 6, wherein the insulating layer includes a layer of air and wherein the window is configured to maintain the layer of air between the active element and the patient's tissue when the active element is in the non-deployed configuration.

11. The device ofclaim 1, wherein the insulating layer includes an electrically insulating outer sleeve configured to selectively slide over the outer surface of the body, the outer sleeve being configured to at least partially cover the active element to electrically insulate the active element from the patient's tissue and uncover the active element to expose the active element to the patient's tissue.

12. The device ofclaim 1, wherein the insulating layer further includes an electrically insulating sheath disposed around at least a portion of the device body, the insulating sheath defining a cutaway portion aligned with the window, the insulating sheath defining at least one raised portion configured to prevent the patient's tissue from prolapsing into the window when the active element is in its non-deployed configuration.

13. The device ofclaim 1, wherein the insulating layer includes an insulating sleeve disposed at least partially around the active element, the insulating sleeve being configured to controllably slide over the active element to selectively electrically insulate the active element from the patient's tissue and expose the active element thereto when the device is in use.

14. The device ofclaim 1, wherein the body is shaped as a non-coring needle.

15. The device ofclaim 1, wherein the insulating layer includes a layer of air and wherein the device body defines at least one raised portion adjacent the window, the at least one raised portion maintaining the layer of air between the active element and the patient's tissue when the active element is in its non-deployed state.

16. The device ofclaim 1, further including suction means for controllably removing fluids from an excision site in the patient's tissue.

17. A method of treating tissue using a probe, the probe including an active element that is extendable out of and retractable back into a window defined in the probe, the active element being electrically connected to a power source, comprising the steps of:

inserting the probe into the tissue;

electrically insulating the active element from the tissue;

energizing the active element using power from the power source, and

exposing the energized active element to the tissue.

18. The method ofclaim 17, wherein the power source is adapted to supply RF power to the active element.

19. The method ofclaim 18, wherein the insulating step includes a step of maintaining an electrically insulating layer between the active element and the tissue.

20. The method ofclaim 17, wherein the probe further includes an electrically insulating sliding door and wherein the insulating step includes a step of sliding the door across the window.

21. The method ofclaim 17, further comprising the step of inducing hyperthermia and necrosis in the tissue exposed to the active element.

22. The method ofclaim 17, further comprising the step of inducing hypothermia and necrosis in the tissue exposed to the active element.

23. The method ofclaim 17, wherein the probe further includes an electrically insulating outer sleeve adapted to slide over an outer surface of the probe and wherein the insulating step includes a step of sliding the outer sleeve over the window.

24. The method ofclaim 17, wherein the probe further includes an insulating sheath around at least a portion of the probe body, the insulating sheath including at least one raised portion adjacent the window and wherein the insulating step includes a step of maintaining the active element retracted within the window.

25. The method ofclaim 17, wherein the insulating step includes a step of maintaining the active element retracted within the window.

26. The method ofclaim 17, wherein the probe further includes an insulating sleeve adapted to slide over the active element and wherein the insulating step includes a step of sliding the insulating sleeve over the active element.

27. The method ofclaim 17, wherein the insulating step includes a step of creating or maintaining a layer of air between the active element and the tissue.

28. The method ofclaim 17, wherein the probe further includes an inflatable balloon disposed adjacent the window, and wherein the insulating step further includes a step of inflating the balloon to create a layer of air between the tissue and the active element.

29. An electrosurgical device, comprising:

a device body, the body defining a proximal end and a distal end;

an active element coupled to the body, the active element being adapted to be controllably energized from a power source, and

means for selectively electrically insulating and exposing the active element from and to a patient's tissue when the device is in use.

30. The device ofclaim 29, wherein the active element is configured to selectively assume a non-deployed configuration in which the active element is recessed within the body and a variable deployed configuration in which the active element at least partially emerges from the body.

31. The device ofclaim 29, wherein the active element is configured to carry out at least one of tissue ablation, dissection, fulguration, cautery, desiccation, hyperthermia and hypothermia.

32. The device ofclaim 29, wherein the active element is configured to be energized by an RF power source.

33. The device ofclaim 29, wherein the device body defines a window disposed near the distal end of the body, the active element being configured to selectively retract into and extend from the window.

34. The device ofclaim 29, wherein a window is defined within the body and wherein the insulating means includes an electrically insulating sliding door mounted within the body, the sliding door being configured to selectively cover at least a portion of the window.

35. The device ofclaim 34, wherein the sliding door is configured to slide between a variable first position in which at least a portion of the active element is exposed through the window and a second position in which the sliding door electrically insulates the active element from the patient's tissue.

36. The device ofclaim 33 wherein the insulating means are integral with the window and wherein the window is configured to prevent tissue from prolapsing therein and making physical and/or electrical contact with the active element when the active element is in a non-deployed configuration.

37. The device ofclaim 29, wherein the insulating means includes an electrically insulating outer sleeve configured to selectively slide over the outer surface of the body, the outer sleeve being configured to at least partially cover the active element and electrically insulate the active element from the patient's tissue when the device is in use and the active element is in a non-deployed configuration.

38. The device ofclaim 29, wherein the insulating means includes an electrically insulating sleeve disposed at least partially around the active element, the insulating sleeve being configured to controllably slide over the active element to selectively electrically insulate the active element from the patient's tissue and expose the active element thereto when the device is in use.

39. The device ofclaim 29, wherein the insulating means are integral with the body and define at least one raised portion, the at least one raised portion being configured to prevent tissue from making physical and/or electrical contact with the active element until the active element is deployed.

40. The device ofclaim 29, wherein the insulating means includes an electrically insulating sheath disposed over the body, the insulating sheath defining at least one raised portion configured to prevent the patient's tissue from coming into contact with the active element until the active element is deployed.

41. The device ofclaim 29, wherein the active element is shaped as a ring and wherein the insulating means are integral with the distal end of the body, the ring-shaped active element being configured to be recessed away from the distal end of the body until fully energized.

42. An electrosurgical device adapted for insertion into tissue, comprising:

a device body,

an RF energizable active element disposed within the device body, and

an insulating structure, wherein at least one of the device body and the insulating structure is configured to insulate the active element from the tissue until the active element is sufficiently energized to be therapeutically effective when the active element is brought into contact with the tissue.

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