Patent Description:
In terms of RFA (Radiofrequency Ablation) electrode probes used for clinical purposes, at present unipolar electrode probe is the most commonly used type. However, such a unipolar electrode probe system has a large ablation range and therefore may easily burn the normal superficial skin when used to treat lesions right underneath the skin. The unipolar electrode probe system may also put patients having heart disease or carrying pacemakers, pregnant women, and fetuses at risk.

As an attempt to solve the aforementioned problems of the unipolar electrode probe, the bipolar electrode probe has been proposed for clinical uses. Nevertheless, the existing bipolar electrode probe still faces the following problems. First, the bipolar electrode probe is formed by coupling the active electrode, the insulation layer, and the passive electrode, but the mechanical strength may be weak at the junction and the probe may easily break during operation, or the cooling water inside may leak from the junction. Second, for the bipolar electrode probe, the length of the ablation region cannot be adjusted. Generally, the length of the conductive region of the bipolar electrode probe is designed to be about <NUM> and thus the bipolar electrode probe cannot be used to ablate a target tissue of <NUM> or shorter. Third, for the bipolar electrode probe, it is required to dispose electrically isolated conductive wires and solder joints inside. For this reason, the bipolar electrode probe has a complicated structure and is difficult to manufacture and be made compact.

In view of the above, how to design a bipolar electrode probe that has a simple structure and an adjustable ablation range is an issue that needs to be addressed in this field. Document <CIT> discloses a method and apparatus for treating an intraosseous nerve. The method includes positioning a hollow shaft through the cortical shell of a vertebral body and into a cancellous bone region of the vertebral body. The hollow shaft includes an annular wall having a longitudinal bore therein, a proximal portion and a distal portion, and a first window extending transversely through the annular wall. An electrosurgical probe is advanced within the longitudinal bore from the proximal portion toward the distal portion. The electrosurgical probe includes a first treatment element at a distal end of the probe, wherein the first treatment element being in electrical connection with a power supply. The first treatment element is slidably disposed within the longitudinal bore so that the first treatment element is advanced radially outward from the window and shaft to affect treatment of the intraosseous nerve within the cancellous bone region. Document <CIT> discloses an electrosurgical device having a tubular outer shaft and an inner shaft. The tubular outer shaft includes an axis and a distal end region. The distal end region includes a distal-most tip and a cutting edge defining a window in the outer shaft proximal along the axis to the distal-most tip. The inner shaft inner shaft coaxially maintained within the outer shaft such that the inner shaft is movable about the axis with respect to the outer shaft and wherein a portion of the inner shaft is exposed in the window of the outer shaft. A first electrode is disposed on the outer shaft in a region proximal along the axis to the window, and a second electrode is electrically isolated from the first electrode and disposed on the inner shaft. The second electrode is exposed in the window of the outer shaft.

The present invention is defined by appended claim <NUM>.

Preferred arrangements are disclosed in the dependent claims.

The disclosure provides a bipolar electrode probe, which includes: a conductive needle, an insulation layer, a conductive sleeve, and an insulation sleeve. The conductive needle has a longitudinal direction and a transverse direction perpendicular to the longitudinal direction. The insulation layer covers the conductive needle and has a first opening. The conductive sleeve covers the insulation layer and has a second opening. The insulation sleeve covers the conductive sleeve. When the bipolar electrode probe is turned on, a longitudinal electric field is formed from a front end of the conductive needle to the conductive sleeve along the longitudinal direction; and a transverse electric field is formed from the conductive needle to the conductive sleeve via the first opening and the second opening along the transverse direction.

To make the aforementioned more comprehensible, several embodiments accompanied with drawings are described in detail as follows.

<FIG> is a schematic view of an exploded state of a bipolar electrode probe according to an embodiment of the disclosure. <FIG> is a schematic view of a combined state of the bipolar electrode probe according to an embodiment of the disclosure. Referring to <FIG>, the bipolar electrode probe <NUM> includes: a conductive needle <NUM>, an insulation layer <NUM>, a conductive sleeve <NUM>, and an insulation sleeve <NUM> from the inside to the outside. Embodiments of the bipolar electrode probe <NUM> and embodiments of each component will be described hereinafter.

The conductive needle <NUM> has a longitudinal direction x and a transverse direction y perpendicular to the longitudinal direction x. The insulation layer <NUM> covers the conductive needle <NUM> and has a first opening <NUM>. The conductive sleeve <NUM> covers the insulation layer <NUM> and has a second opening <NUM>. The insulation sleeve <NUM> covers the conductive sleeve <NUM>. When the bipolar electrode probe <NUM> is turned on, a longitudinal electric field E1 is formed from a front end of the conductive needle <NUM> to the conductive sleeve <NUM> along the longitudinal direction x. A transverse electric field E2 is formed from the conductive needle <NUM> to the conductive sleeve <NUM> via the first opening <NUM> and the second opening <NUM> along the transverse direction y. In another embodiment, the insulation sleeve <NUM> is movable along the longitudinal direction x, so as to adjust an ablation range of the bipolar electrode probe <NUM> (which will be described later).

It should be noted that, in the region where the transverse electric field E2 is generated, a small longitudinal electric field may be formed from the conductive needle <NUM> to the conductive sleeve <NUM> via the first opening <NUM> and the second opening <NUM> along the longitudinal direction x, but the influence thereof may be ignored and thus is not discussed here. Moreover, in an embodiment, the conductive needle <NUM> serves as an active electrode while the conductive sleeve <NUM> serves as a passive electrode, for example, but the disclosure is not limited thereto. In other embodiments, the conductive needle <NUM> may serve as the passive electrode and the conductive sleeve <NUM> may serve as the active electrode.

Referring to <FIG>, the bipolar electrode probe <NUM> has a front ablation region and a rear ablation region. Specifically, the longitudinal electric field E1 at the front is for ablating a front section of the target tissue, and the transverse electric field E2 at the rear is for ablating a rear section of the target tissue. An embodiment of the structure of the bipolar electrode probe <NUM> will be described hereinafter.

<FIG> is a schematic view of the bipolar electrode probe according to an embodiment of the disclosure. <FIG> shows the longitudinal direction x, the transverse direction y, and a direction z perpendicular to the longitudinal direction x and the transverse direction y. <FIG> is a schematic cross-sectional view taken along the plane I of <FIG>. Referring to <FIG> and <FIG>, the area of the first opening <NUM> is smaller than the area of the second opening <NUM>, such that a portion of the insulation layer <NUM> is exposed by the second opening <NUM>, and the exposed region of the insulation layer <NUM> has a longitudinal insulation distance dx and a transverse insulation distance dy.

Referring to <FIG>, <FIG>, in an embodiment, in the region of the transverse electric field E2, the longitudinal insulation distance dx is from a front end of the second opening <NUM> to a front end of the first opening <NUM> along the longitudinal direction x. The transverse insulation distance dy is from one end of the second opening <NUM> to one end of the first opening <NUM> on the same side along the transverse direction y. The longitudinal insulation distance dx is to ensure the longitudinal isolation distance between the conductive needle <NUM> and the conductive sleeve <NUM>, so as to prevent a large current from flowing through the tissue due to a short isolation distance. If the isolation distance between the conductive needle <NUM> and the conductive sleeve <NUM> is too short, a large current may flow through the tissue to cause the temperature to rise too quickly and result in coking in a short time, and the ablation range will be only about <NUM> of the probe surface. Such a small ablation range is inadequate for clinical use.

In addition, as shown in <FIG>, the transverse insulation distance dy ensures the transverse isolation distance between the conductive needle <NUM> and the conductive sleeve <NUM>, so as to maintain a current path that is sufficient for generating the transverse electric field E2 and prevent reduction of the ablation range due to a short current path.

Referring to <FIG>, in an embodiment, in the region of the transverse electric field E2, a ratio of the area of the conductive needle <NUM> exposed by the first opening <NUM> to the area of the conductive sleeve <NUM> in the region outside the second opening <NUM> is <NUM>:<NUM> to <NUM>:<NUM>.

Referring to <FIG>, in the region of the transverse electric field E2, the area of the conductive needle <NUM> is L1×W1, wherein L1 is a length of the conductive needle <NUM> along the longitudinal direction x and W1 is a length of the conductive needle <NUM> in a circumferential direction; moreover, the area of the conductive sleeve <NUM> is L2×W2, wherein L2 is a length of the conductive sleeve <NUM> along the longitudinal direction x and W2 is a length of the conductive sleeve <NUM> in the circumferential direction. In an embodiment, the area of the conductive needle <NUM> may be equal to the area of the conductive sleeve <NUM>, so as to generate the transverse electric field E2 uniformly. In other embodiments, when the ratio of the area of the conductive needle <NUM> to the area of the conductive sleeve <NUM> in the region of the transverse electric field E2 is set to <NUM>:<NUM> to <NUM>:<NUM>, the transverse electric field E2 may be generated uniformly.

In addition, referring to <FIG>, in an embodiment, a ratio of the area of a conductive region where the longitudinal electric field E1 exists to the area of a conductive region where the transverse electric field E2 exists is <NUM>:<NUM> to <NUM>:<NUM>. Thereby, the front ablation region (the longitudinal electric field E1) and the rear ablation region (the transverse electric field E2) of the bipolar electrode probe <NUM> may be set to a proper ratio.

Further, referring to <FIG>, in the region of the transverse electric field E2, the longitudinal insulation distance dx and the transverse insulation distance dy define an insulation area, and the area of the conductive needle <NUM> exposed by the first opening <NUM> and the area of the conductive sleeve <NUM> outside the second opening <NUM> define a conductive area, and a ratio of the insulation area to the conductive area is <NUM>:<NUM> to <NUM>:<NUM>.

As shown in <FIG>, in the region of the transverse electric field E2, the insulation area is the area of the insulation layer <NUM> that exists in the region of the longitudinal insulation distance dx and the transverse insulation distance dy. In the region of the transverse electric field E2, the conductive area is a sum of the area L1×W1 of the conductive needle <NUM> and the area L2×W2 of the conductive sleeve <NUM>. Through calculation, it is obtained that the ratio of the insulation area to the conductive area is <NUM>:<NUM> to <NUM>:<NUM>. With this setting, the transverse electric field E2 is generated uniformly, so as to perform uniform ablation.

<FIG> are schematic views showing that the insulation sleeve moves back and forth along the longitudinal direction according to another embodiment of the disclosure. Referring to <FIG>, relative to the conductive needle <NUM>, the insulation layer <NUM>, and the conductive sleeve <NUM> disposed at fixed locations, the insulation sleeve <NUM> is configured to be movable back and forth along the longitudinal direction x. As shown in <FIG>, when the insulation sleeve <NUM> moves toward the front end of the bipolar electrode probe <NUM>, the larger transverse electric field E2 changes to a smaller transverse electric field E2'.

In other words, the range of the transverse electric field E2 (ablation region) may be adjusted by moving the insulation sleeve <NUM> back and forth along the longitudinal direction x. When ablating a superficial tissue of the epidermis, the insulation sleeve <NUM> may be moved to completely close the transverse electric field E2 and to only use the longitudinal electric field E1 for ablation, so as to prevent burning the epidermis of the patient. In addition, when the insulation sleeve <NUM> is moved toward the front end of the bipolar electrode probe <NUM>, the range of the transverse electric field E2 is reduced to achieve a smaller ablation region; on the other hand, when the insulation sleeve <NUM> is moved toward the rear end of the bipolar electrode probe <NUM>, the range of the transverse electric field E2 is increased to achieve a larger ablation region.

In the disclosure, even if the insulation sleeve <NUM> moves back and forth in the longitudinal direction x, the strength of the transverse electric field E2 in the transverse direction y remains uniform. Therefore, the ablation region is maintained uniform in the transverse direction y.

In the embodiments of <FIG>, the number of the first openings <NUM> may be equal to the number of the second openings <NUM>. The number of the first openings <NUM> is one or more, and the number of the second openings <NUM> is one or more. Thereby, an electrode pair is formed (as shown in <FIG>). In other embodiments, however, the number of the first openings <NUM> and the number of the second openings <NUM> may be two, three, four, five, six, and so on, respectively.

<FIG> is a schematic view of the bipolar electrode probe according to another embodiment of the disclosure. <FIG> is a schematic cross-sectional view taken along the plane O of <FIG>. <FIG> is a schematic cross-sectional view taken along the plane P of <FIG>. <FIG> is a schematic cross-sectional view taken along the plane Q of <FIG>. In a bipolar electrode probe <NUM>, identical components are represented by identical reference numerals as shown in <FIG>, and therefore detailed descriptions thereof are not repeated hereinafter. Referring to <FIG> and <FIG>, in this embodiment, the number of the first openings <NUM> is four and the number of the second openings <NUM> is four, so as to form four electrode pairs (as shown in <FIG>).

<FIG> is a partially enlarged view of the bipolar electrode probe of <FIG>. Referring to <FIG>, similarly, in the bipolar electrode probe <NUM>, the region exposed by the insulation layer <NUM> has the longitudinal insulation distance dx and the transverse insulation distance dy. The longitudinal insulation distance dx is to ensure the longitudinal isolation distance between the conductive needle <NUM> and the conductive sleeve <NUM> in the longitudinal direction, so as to prevent a large current from flowing through the tissue due to a short isolation distance. In addition, the transverse insulation distance dy is maintained to ensure the transverse isolation distance between the conductive needle <NUM> and the conductive sleeve <NUM>, so as to maintain a current path that is sufficient for generating the transverse electric field E2 and prevent reduction of the ablation range due to a short current path.

<FIG> is a partially enlarged view of the bipolar electrode probe of <FIG>. Similar to the description of <FIG>, as shown in <FIG>, in the region of the transverse electric field E2, the area of the conductive needle <NUM> may be equal to the area of the conductive sleeve <NUM>, so as to generate the transverse electric field E2 uniformly. In another embodiment, when the ratio of the area of the conductive needle <NUM> to the area of the conductive sleeve <NUM> is set to <NUM>:<NUM> to <NUM>:<NUM>, the transverse electric field E2 may be generated uniformly.

<FIG> is a schematic view of the bipolar electrode probe according to another embodiment of the disclosure. Components identical to those in the above embodiments of <FIG> are represented by identical reference numerals, and therefore detailed descriptions thereof are not repeated hereinafter. Referring to <FIG>, a bipolar electrode probe <NUM> of this embodiment may further include: an infusion member <NUM> disposed at the rear ends of the insulation layer <NUM> and the conductive sleeve <NUM>. The infusion member <NUM> is disposed to allow a liquid substance L to pass through a gap between the insulation layer <NUM> and the conductive sleeve <NUM> to be outputted from the first opening <NUM> and the second opening <NUM>.

Referring to <FIG>, the liquid substance L enters the gap between the insulation layer <NUM> and the conductive sleeve <NUM> in the direction indicated by the arrow and flows out from the first opening <NUM> and the second opening <NUM> at the front to be infused into the target tissue. In an embodiment, the liquid substance L may be: an anesthetic drug for easing pain in the ablation region or physiological saline for increasing the volume of ablation. When the bipolar electrode probe <NUM> is used for ablation on an air-related organ (e.g., lungs), infusion of physiological saline facilitates the ablation and solves the problem of poor ablation effect resulting from that gas cannot effectively transfer current and heat.

The infusion member <NUM> may further include sealing members <NUM> disposed at a junction between the infusion member <NUM> and the insulation layer <NUM> and a junction between the infusion member <NUM> and the conductive sleeve <NUM>, so as to properly assemble the infusion member <NUM> to the bipolar electrode probe <NUM> and enable the liquid substance L to be properly inputted into the inlet of the infusion member <NUM>, and then through the gap between the insulation layer <NUM> and the conductive sleeve <NUM>, to be outputted to the target tissue from the first opening <NUM> and the second opening <NUM>.

As shown in <FIG>, the infusion member <NUM> is assembled to the bipolar electrode probe <NUM> that has four first openings <NUM> and four second openings <NUM>; however, the infusion member <NUM> may also be assembled to the bipolar electrode probe <NUM> that has one first opening <NUM> and one second opening <NUM>, as shown in <FIG>.

<FIG> is a table of comparison between the bipolar electrode probe of <FIG> and the conventional unipolar electrode probe used for ablating the target tissue. Referring to <FIG>, when a target length for ablation of the target tissue is <NUM>, it is known that the unipolar electrode probe forms an ablation region of <NUM> in the longitudinal direction and an ablation region of <NUM> in the transverse direction; on the other hand, the bipolar electrode probe <NUM> according to the embodiments of the disclosure forms an ablation region of <NUM> in the longitudinal direction and an ablation region of <NUM> in the transverse direction, which at least achieves an ablation effect similar to the unipolar electrode probe.

Referring to <FIG> again, when the target length for ablation of the target tissue is <NUM>, it is known that the unipolar electrode probe forms an ablation region of <NUM> in the longitudinal direction and an ablation region of <NUM> in the transverse direction; on the other hand, the bipolar electrode probe <NUM> according to the embodiments of the disclosure forms an ablation region of <NUM> in the longitudinal direction and an ablation region of <NUM> in the transverse direction, which at least achieves an ablation effect similar to the unipolar electrode probe. It is known from the above that the length of the ablation region formed by the unipolar electrode probe in the longitudinal direction is <NUM>, which exceeds the target length <NUM> and the operation accuracy drops. However, the length of the ablation region formed by the bipolar electrode probe <NUM> of the disclosure in the longitudinal direction is <NUM>, which is close to the target length <NUM> and achieves favorable operation accuracy.

Referring to <FIG> again, when the target length for ablation of the target tissue is <NUM>, it is known that the unipolar electrode probe forms an ablation region of <NUM> in the longitudinal direction and an ablation region of <NUM> in the transverse direction; on the other hand, the bipolar electrode probe <NUM> according to the embodiments of the disclosure forms an ablation region of <NUM> in the longitudinal direction and an ablation region of <NUM> in the transverse direction, which at least achieves an ablation effect similar to the unipolar electrode probe.

Claim 1:
A bipolar electrode probe (<NUM>, <NUM>, <NUM>), comprising:
a conductive needle (<NUM>) having a longitudinal direction (x) and a transverse direction (y) perpendicular to the longitudinal direction (x);
an insulation layer (<NUM>) covering the conductive needle (<NUM>) and having at least a first opening (<NUM>);
a conductive sleeve (<NUM>) covering the insulation layer (<NUM>) and having at least one second opening (<NUM>); and
an insulation sleeve (<NUM>) covering the conductive sleeve (<NUM>), wherein the insulation sleeve (<NUM>) is configured to be movable back and forth along the longitudinal direction (x),
wherein a needle end portion of the conductive needle (<NUM>) is exposed from distal ends of the insulation layer (<NUM>), the conductive sleeve (<NUM>) and the insulation sleeve (<NUM>),wherein when the bipolar electrode probe (<NUM>, <NUM>, <NUM>) is applied with power and a voltage is applied between the conductive needle (<NUM>) and the conductive sleeve (<NUM>) at a rear end of the bipolar electrode probe (<NUM>, <NUM>, <NUM>), a longitudinal electric field (E1) is formed from a front end of the conductive needle (<NUM>) to the conductive sleeve (<NUM>) along the longitudinal direction (x), and
a transverse electric field (E2, E2') is formed from the conductive needle (<NUM>) to the conductive sleeve (<NUM>) via the at least one first opening (<NUM>) and the at least one second opening (<NUM>) along the transverse direction (y);
wherein the bipolar electrode probe (<NUM>, <NUM>, <NUM>) has: a front ablation region, where the longitudinal electric field (E1) is formed, and a rear ablation region, where the transverse electric field (E2, E2') is formed;
wherein a tip of the insulation layer (<NUM>) is protruding distally from the conductive sleeve (<NUM>);
wherein the conductive sleeve (<NUM>) is protruding distally from the insulation sleeve (<NUM>);
wherein
in a region of the transverse electric field (E2, E2'), a longitudinal insulation distance (dx) exists between a front end of the at least one second opening (<NUM>) and a front end of the at least one first opening (<NUM>) along the longitudinal direction (x); and
a transverse insulation distance (dy) exists between an end of the at least one second opening (<NUM>) and an end of the at least one first opening (<NUM>) on a same side along the transverse direction (y).