Electrode replaceable high frequency electrotome

Abstract

The utility model provides a kind of electrode replaceable high-frequency electrotome, including handle, insulating sheath, connecting piece, jaw structure and electrode;The proximal end of insulating sheath is connected with handle, and the distal end of insulating sheath extends to form operating end, and the proximal end of connecting piece is connected with handle, and the distal end of connecting piece extends to the inside of insulating sheath;Jaw structure includes the insertion part of tubular and at least two jaw parts, and the proximal end of insertion part is fixedly connected with the distal end of connecting piece, and at least two jaw parts are fixedly connected with the distal end of insertion part, and are evenly distributed along the circumference of insertion part and extend to distal end, and the inside of jaw part is provided with the protrusion towards the axis of insertion part;The proximal end of electrode is provided with annular clamping groove, and the proximal end of electrode is inserted into insertion part from far to near, and at least two jaw parts are clamped with annular clamping groove by protrusion, and electrode is pulled out from insertion part from near to far, and protrusion can be disengaged with annular clamping groove. Realize one machine multiuse, reduce surgical cost.

Description

Technical Field

[0001] This utility model relates to the field of medical device technology, and in particular to a high-frequency electrosurgical unit with replaceable electrodes. Background Technology

[0002] A high-frequency electrosurgical unit (HFEMU) is an electrosurgical instrument that replaces mechanical scalpels for tissue cutting. It heats tissue by generating a high-frequency, high-voltage current at the tip of its effective electrode, achieving tissue separation and coagulation, thus achieving cutting and hemostasis. During use, a suitable neutral electrode plate is required. This plate is attached to a muscle-rich area of ​​the patient, guiding the current collected within the body back to the HFEMU and other instruments, forming a complete high-frequency circuit. This disperses the current during high-frequency surgery, reducing the risk of current concentration, safely collecting and delivering the current to the outside of the body, and protecting the patient's safety.

[0003] Currently, a single electrosurgical unit typically comes with a fixed electrode, and the electrode and the electrosurgical unit are integrated. During surgery, to meet the requirements of different surgical steps and diverse tissue types, it is often necessary to switch between electrosurgical units with different types of electrodes to work together to complete the procedure. This means that multiple electrosurgical units with different electrodes need to be used in a single operation, which can lead to high surgical costs for patients.

[0004] Therefore, there is an urgent need to provide a high-frequency electrosurgical unit with replaceable electrodes. Utility Model Content

[0005] (a) Technical problems to be solved

[0006] In view of the problems existing in the above-mentioned technology, the present invention provides solutions to at least some extent. Therefore, the purpose of the present invention is to propose a high-frequency electrosurgical unit with replaceable electrodes, enabling multiple uses and reducing surgical costs.

[0007] (II) Technical Solution

[0008] To achieve the above objectives, the main technical solutions adopted by this utility model include:

[0009] This utility model provides a high-frequency electrosurgical unit with replaceable electrodes, including a handle, an insulating sheath, a connector, a claw structure, and an electrode. The proximal end of the insulating sheath is connected to the handle, and the distal end of the insulating sheath extends to form an operating end. The proximal end of the connector is connected to the handle, and the distal end of the connector extends into the interior of the insulating sheath. The claw structure includes an insertion part and at least two claw parts. The insertion part is tubular, and the proximal end of the insertion part is fixedly connected to the distal end of the connector. At least two claw parts are fixedly connected to the distal end of the insertion part, and the at least two claw parts are evenly distributed along the circumference of the insertion part and extend to the distal end. The inner side of the claw parts is provided with a protrusion facing the axis of the insertion part. An annular groove is provided on the proximal sidewall of the electrode. The proximal end of the electrode is inserted into the insertion part from the distal end to the proximal end. The at least two claw parts engage with the annular groove through the protrusion. The electrode is pulled out from the insertion part from the proximal end to the distal end. The protrusion can disengage from the annular groove.

[0010] Optionally, the insertion part and at least two claw parts are both made of metal. When the at least two claw parts engage with the annular groove through the protrusion, the claw parts generate radial clamping force through their own elastic deformation, and the protrusion contacts the bottom surface of the annular groove. The connector is made of metal, with the proximal end of the connector for electrical connection to the power supply and the distal end of the connector for electrical connection to the insertion part. Alternatively, the connector includes a support body and a conductive wire embedded in the support body, with the first end of the conductive wire for electrical connection to the power supply and the second end of the conductive wire for electrical connection to the insertion part.

[0011] Optionally, the insertion part is made of metal, and a support surface perpendicular to the axis of the insertion part and facing the distal end is formed on the inner wall of the insertion part. A metal compression spring is fixedly connected to the support surface, and the metal compression spring is electrically connected to the support surface. When at least two claw parts are engaged with the annular groove through the protrusion, the metal compression spring abuts against the proximal end wall of the electrode, and the metal compression spring is compressed and deformed.

[0012] Optionally, the protrusion has a distal side facing the distal end and a proximal side facing the proximal end, the distal side extending from the claw portion toward the axis of the insertion portion and gradually inclined toward the proximal end, and the proximal side extending from the claw portion toward the axis of the insertion portion and gradually inclined toward the distal end.

[0013] Optionally, the protrusion is an arc-shaped protrusion extending circumferentially along the insertion part, and the cross-sectional shape of the arc-shaped protrusion is trapezoidal.

[0014] Optionally, the claw structure is located inside the insulating sheath, and an axially extending guide key is provided on the proximal outer wall of the electrode, while an axially extending guide groove is provided on the distal inner wall of the insulating sheath. The proximal end of the electrode is inserted into the insertion part, and the guide key is inserted into the guide groove to restrict the circumferential rotation of the electrode.

[0015] Optionally, both the electrode and the connector are tubular. The proximal end of the connector is used to communicate with the outlet of the water pump, and the proximal end of the insert is connected to the distal end of the connector. An annular mounting groove is provided on the outer peripheral wall of the proximal end of the electrode, and a sealing ring is installed in the annular mounting groove. The proximal end of the electrode is inserted into the insert, and the sealing ring is sealed to the inner wall of the insert.

[0016] Optionally, the proximal end of the connector located inside the handle can be driven to move linearly between a first position and a second position arranged sequentially from proximal to distal; when the connector is in the first position, after the proximal end of the electrode is inserted into the insert, the distal end of the electrode extends out of the insulating sheath.

[0017] Optionally, the high-frequency electrosurgical unit also includes an adapter tube, which is fixedly installed inside the handle. The adapter tube is used to communicate with the outlet of the water pump, and the proximal end of the connector is connected to the adapter tube. During the linear movement of the connector, the proximal end of the connector is always connected to the adapter tube.

[0018] Optionally, the electrode is one of a needle electrode, a blade electrode, a spherical electrode, a hook electrode, a ring electrode, and an insulated tip electrode.

[0019] (III) Beneficial Effects

[0020] The beneficial effects of this utility model are:

[0021] The high-frequency electrosurgical unit provided by this utility model, through the cooperation of the claw structure and the annular groove on the electrode, can realize the installation and removal of the electrode on the operating end of the high-frequency electrosurgical unit. Thus, during the operation, the doctor can change the electrode of the high-frequency electrosurgical unit according to the requirements of different surgical steps and tissue types to complete the operation, realizing multiple uses of one machine, greatly reducing the number of electrosurgical units used during the operation, and reducing the cost of surgery. Attached Figure Description

[0022] This utility model is described with reference to the following drawings:

[0023] Figure 1 This is a schematic diagram of the high-frequency electrosurgical unit according to Embodiment 1, wherein the connector is in the first position;

[0024] Figure 2 This is a structural schematic diagram of a high-frequency electrosurgical unit according to Embodiment 1, showing the distal cross-sectional structure of the shaft assembly and the connector in the first position;

[0025] Figure 3 yes Figure 2 Enlarged view of point A in the middle;

[0026] Figure 4 This is an exploded schematic diagram of the spherical electrode and claw structure according to Example 1;

[0027] Figure 5This is a schematic diagram of the hook-shaped electrode according to Example 1;

[0028] Figure 6 This is a schematic diagram of the blade-shaped electrode according to Example 1;

[0029] Figure 7 This is a schematic diagram of the needle electrode according to Example 1.

[0030] [Explanation of Labels in the Attached Image]

[0031] 1: Handle;

[0032] 2: Insulating sheath;

[0033] 3: Connectors;

[0034] 41: Insertion part; 42: Claw part; 43: Protrusion; 45: Support surface;

[0035] 5: Electrode;

[0036] 51: Annular slot; 52: Annular mounting slot;

[0037] 6: Sealing ring;

[0038] 7: Ceramic sleeve. Detailed Implementation

[0039] To better explain and facilitate understanding of this utility model, a detailed description of its specific embodiments is provided below with reference to the accompanying drawings. In this document, "near" refers to the side closer to the operator, and "far" refers to the side closer to the patient. The directional terms "upper," "lower," "front," "back," "left," and "right" used in this document are... Figure 1 The orientation is taken as a reference, where the direction from near to far is also the direction from back to front.

[0040] Example 1

[0041] like Figures 1 to 4 As shown, this embodiment provides a high-frequency electrosurgical unit with replaceable electrodes. The high-frequency electrosurgical unit includes a handle 1 and a shaft assembly connected sequentially from near to far.

[0042] The shaft assembly includes an insulating sheath 2, a connector 3, a claw structure, and an electrode 5. The proximal end of the insulating sheath 2 is connected to the handle 1, and the distal end of the insulating sheath 2 extends to form an operating end. The proximal end of the connector 3 is connected to the handle 1, and the distal end of the connector 3 extends into the interior of the insulating sheath 2. The claw structure is located inside the insulating sheath 2 and includes an insertion part 41 and at least two claw parts 42. The insertion part 41 is tubular, and the proximal end of the insertion part 41 is fixedly connected to the distal end of the connector 3. At least two claw parts 42 are fixedly connected to the distal ends of the insertion part 41, and at least two claw parts 42 are evenly distributed along the circumference of the insertion part 41 and extend distally. The inner side of the claw part 42 is provided with a protrusion 43 facing the axis of the insertion part 41.

[0043] An annular groove 51 is provided on the proximal sidewall of electrode 5. During the process of inserting electrode 5 into insertion part 41 through the cavity formed by at least two claw portions 42, electrode 5 can expand all claw portions 42 outward to move into insertion part 41 until protrusion 43 falls into an annular groove 51, realizing the engagement of electrode 5 with the claw structure and completing the installation of electrode 5 on the claw structure. During the process of pulling electrode 5 out of insertion part 41 from near to far, protrusion 43 can disengage from an annular groove 51, and then electrode 5 can expand all claw portions 42 outward to move towards the proximal end until electrode 5 is completely detached from the claw structure, realizing the disassembly of electrode 5 from the claw structure.

[0044] With this configuration, the high-frequency electrosurgical unit can be installed and removed from the high-frequency electrosurgical unit through the cooperation of the claw structure and the annular groove 51 on the electrode 5. Thus, during the operation, the doctor can replace the electrode 5 of the high-frequency electrosurgical unit according to the requirements of different surgical steps and tissue types to complete the operation, realizing multiple uses of one machine, greatly reducing the number of electrosurgical units used during the operation, and reducing the cost of surgery.

[0045] It should be noted that in this embodiment, all claw portions 42 are elastic elements.

[0046] Preferably, the insertion part 41 and at least two claw parts 42 are both made of metal. When the at least two claw parts 42 are engaged with the annular groove 51 by the protrusion 43, the claw parts 42 generate radial clamping force through their own elastic deformation, and the protrusion 43 contacts the bottom surface of the annular groove 51. The connector 3 is made of metal, with its proximal end for electrical connection to a power source and its distal end for electrical connection to the insertion part 41. In this way, the connector 3, the insertion part 41, the claw parts 42, and the electrode 5 form a conductive path for supplying electrical energy to the electrode 5. The radial clamping force of the claw parts 42 can provide a stable contact pressure between the protrusion 43 and the bottom surface of the annular groove 51 to form a stable low-resistance conductive path. Furthermore, the friction during the insertion and removal of the electrode 5 can remove the oxide layer or contaminants from the contact surface between the protrusion 43 and the annular groove 51, maintaining conductivity.

[0047] Of course, using metal for connector 3 is only a preferred option. It is conceivable that connector 3 includes a supporting body and a conductive wire embedded in the supporting body. The first end of the conductive wire is used for electrical connection with the power source, and the second end of the conductive wire is used for electrical connection with the insertion part 41, which can also stably transmit electrical energy to the electrode 5 through connector 3. The supporting body is generally made of plastic.

[0048] More preferably, a support surface 45 perpendicular to the axial direction of the insertion part 41 and facing the distal end is formed on the inner wall of the insertion part 41. A metal compression spring (not shown in the figure) is fixedly connected to the support surface 45, and the metal compression spring is electrically connected to the support surface 45. When at least two claw parts 42 are engaged with the annular groove 51 through the protrusion 43, the metal compression spring abuts against the proximal end wall of the electrode 5, and the metal compression spring is compressed and deformed. In this way, a conductive path can be formed between the insertion part 41 and the electrode 5 by the metal compression spring. The redundant conductive design further ensures the electrical conductivity stability between the claw structure and the electrode 5. The compression deformation of the metal compression spring can provide a stable contact pressure between the proximal end wall of the electrode 5 and the metal compression spring, ensuring good conductivity between the insertion part 41 and the electrode 5.

[0049] More preferably, the number of claw portions 42 in the claw structure is 2 to 6. Specifically, in this embodiment, the number of claw portions 42 is 4. Specifically, in this embodiment, the protrusion 43 is located at the distal end of the claw portion 42.

[0050] Preferably, the protrusion 43 has a distal side facing the distal end and a proximal side facing the proximal end. The distal side extends from the claw portion 42 toward the axis of the insertion portion 41 and gradually slopes toward the proximal end, while the proximal side extends from the claw portion 42 toward the axis of the insertion portion 41 and gradually slopes toward the distal end. This shape of the protrusion 43 facilitates the insertion of the electrode 5 into the cavity formed by at least two claw portions 42 and the outward expansion of all the claw portions 42, while the proximal side facilitates the disengagement of the protrusion 43 from the annular groove 51.

[0051] More preferably, in this embodiment, the protrusion 43 is an arc-shaped protrusion 43 extending circumferentially along the insertion portion 41, and the cross-sectional shape of the arc-shaped protrusion 43 is trapezoidal. Optionally, the cross-sectional shape of the arc-shaped protrusion 43 is triangular or semi-circular.

[0052] Preferably, both the electrode 5 and the connector 3 are tubular. The proximal end of the connector 3, located inside the handle 1, is connected to the outlet of the water pump. The proximal end of the insertion part 41 is connected to the distal end of the connector 3. An annular mounting groove 52 is formed on the outer peripheral wall of the proximal end of the electrode 5, and a sealing ring 6 is installed in the annular mounting groove 52. The proximal end of the electrode 5 is inserted into the insertion part 41, and the electrode 5 is connected to the insertion part 41. The sealing ring 6 is sealed to the inner wall of the insertion part 41. In this way, the high-frequency electrosurgical unit has a water injection function. On the one hand, water can be injected under the mucosa to make the tissue swell and facilitate tissue dissection. On the other hand, water can be sprayed after electrosurgical cutting of tissue to flush out blood clots and expose bleeding points, which facilitates electrocoagulation hemostasis.

[0053] Preferably, the proximal end of the connector 3 located within the handle 1 can be driven to move linearly between a first position and a second position arranged sequentially from proximal to distal; when the connector 3 is in the first position, the distal end of the electrode 5 inserted into the insertion part 41 extends out of the insulating sheath 2. This gives the electrode 5 of the high-frequency electrosurgical unit a telescopic function, allowing adjustment of the electrode 5's working depth as needed.

[0054] More preferably, the high-frequency electrosurgical unit also includes an adapter tube, which is fixedly installed inside the handle 1. The adapter tube is used to communicate with the outlet of the water pump. The proximal end of the connector 3 is slidably connected to and communicates with the adapter tube. During the linear movement of the connector 3, the proximal end of the connector 3 is always in communication with the adapter tube. In this way, the adapter tube ensures that the connector 3 and the outlet of the water pump are always in communication without affecting the linear movement of the connector 3.

[0055] Preferably, electrode 5 is a spherical electrode 5 (e.g., Figure 4 (as shown), hook electrode 5 (as shown) Figure 5 As shown), blade-shaped electrode 5 (as shown) Figure 6 As shown), needle electrode 5 (as shown) Figure 7 (as shown), one of the ring electrode 5 and the insulated tip electrode 5.

[0056] Specifically, in this embodiment, the shaft assembly further includes a ceramic sleeve 7. The proximal end of the ceramic sleeve 7 is inserted into the distal end of the insulating sheath 2 and fixedly connected to the insulating sheath 2. The distal end of the ceramic sleeve 7 extends out of the insulating sheath 2. After the proximal end of the electrode 5 is inserted into the insertion part 41, the distal end of the electrode 5 extends out of the ceramic sleeve 7. Since the insulating sheath 2 is generally made of plastic with a low melting point, by setting the ceramic sleeve 7, the poor thermal conductivity of the ceramic sleeve 7 is utilized to reduce the heat transfer from the electrode 5 to the insulating sheath 2, preventing the insulating sheath 2 from deforming due to heat.

[0057] Example 2

[0058] The main difference between this embodiment and Embodiment 1 is:

[0059] A guide key extending axially is provided on the proximal outer wall of electrode 5, and a guide groove extending axially is provided on the distal inner wall of insulating sheath 2; the proximal end of electrode 5 is inserted into the insertion part, and the guide key is inserted into the guide groove to restrict the circumferential rotation of electrode 5. In this way, the installation stability of electrode 5 is further ensured.

[0060] The remaining contents are the same as in Example 1, and will not be repeated here.

[0061] In the description of this utility model, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this utility model, "a plurality of" means two or more, unless otherwise explicitly specified.

[0062] In this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in this utility model can be understood according to the specific circumstances.

[0063] In this utility model, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "beneath" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0064] In the description of this specification, the terms "one embodiment," "some embodiments," "embodiment," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0065] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make modifications, alterations, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A high-frequency electrosurgical unit with replaceable electrodes, characterized in that, It includes a handle (1), an insulating sheath (2), a connector (3), a claw structure, and an electrode (5); The proximal end of the insulating sheath (2) is connected to the handle (1), the distal end of the insulating sheath (2) extends to form the operating end, the proximal end of the connector (3) is connected to the handle (1), and the distal end of the connector (3) extends into the interior of the insulating sheath (2). The claw structure includes an insertion part (41) and at least two claw parts (42). The insertion part (41) is tubular. The proximal end of the insertion part (41) is fixedly connected to the distal end of the connector (3). At least two claw parts (42) are fixedly connected to the distal end of the insertion part (41). Moreover, at least two claw parts (42) are evenly distributed along the circumference of the insertion part (41) and extend to the distal end. The inner side of the claw part (42) is provided with a protrusion (43) facing the axis of the insertion part (41). An annular groove (51) is provided on the proximal sidewall of the electrode (5). The proximal end of the electrode (5) is inserted into the insertion part (41) from far to near. At least two claws (42) are engaged with the annular groove (51) through protrusions (43). The electrode (5) is pulled out from the insertion part (41) from near to far. The protrusions (43) can disengage from the annular groove (51).

2. The high-frequency electrosurgical unit with replaceable electrodes according to claim 1, characterized in that, The insert (41) and at least two claws (42) are both made of metal. When the at least two claws (42) engage with the annular groove (51) through the protrusion (43), the claws (42) generate radial clamping force through their own elastic deformation, and the protrusion (43) contacts the bottom surface of the annular groove (51). The connector (3) is made of metal. The proximal end of the connector (3) is used to be electrically connected to the power supply, and the distal end of the connector (3) is electrically connected to the insertion part (41); or, the connector (3) includes a support body and a conductive wire embedded in the support body. The first end of the conductive wire is used to be electrically connected to the power supply, and the second end of the conductive wire is electrically connected to the insertion part (41).

3. The high-frequency electrosurgical unit with replaceable electrodes according to claim 1 or 2, characterized in that, The insertion part (41) is made of metal. A support surface (45) perpendicular to the axis of the insertion part (41) and facing the far end is formed on the inner wall of the insertion part (41). A metal compression spring is fixedly connected to the support surface (45), and the metal compression spring is electrically connected to the support surface (45). When at least two claws (42) engage with the annular groove (51) via the protrusion (43), the metal spring comes into contact with the proximal end wall of the electrode (5), and the metal spring is compressed and deformed.

4. The high-frequency electrosurgical unit with replaceable electrodes according to claim 1, characterized in that, The protrusion (43) has a distal side facing the distal end and a proximal side facing the proximal end. The distal side extends from the claw portion (42) toward the axis of the insertion portion (41) and gradually slopes toward the proximal end. The proximal side extends from the claw portion (42) toward the axis of the insertion portion (41) and gradually slopes toward the distal end.

5. The high-frequency electrosurgical unit with replaceable electrodes according to claim 4, characterized in that, The protrusion (43) is an arc-shaped protrusion (43) extending circumferentially along the insertion part (41), and the cross-sectional shape of the arc-shaped protrusion (43) is trapezoidal.

6. The high-frequency electrosurgical unit with replaceable electrodes according to claim 1, characterized in that, The claw structure is located inside the insulating sheath (2). A guide key extending along the axial direction is provided on the outer wall of the proximal end of the electrode (5), and a guide groove extending along the axial direction is provided on the inner wall of the distal end of the insulating sheath (2). The proximal end of the electrode (5) is inserted into the insertion part (41), and the guide key is inserted into the guide groove to restrict the circumferential rotation of the electrode (5).

7. The high-frequency electrosurgical unit with replaceable electrodes according to claim 1, characterized in that, Both the electrode (5) and the connector (3) are tubular. The proximal end of the connector (3) is used to communicate with the outlet of the water pump. The proximal end of the insert (41) is connected to the distal end of the connector (3). An annular mounting groove (52) is provided on the outer peripheral wall of the proximal end of the electrode (5). A sealing ring (6) is installed in the annular mounting groove (52). The proximal end of the electrode (5) is inserted into the insert (41), and the sealing ring (6) is sealed to the inner wall of the insert (41).

8. The high-frequency electrosurgical unit with replaceable electrodes according to claim 7, characterized in that, The proximal end of the connector (3) located in the handle (1) can be driven to make linear motion between the first position and the second position arranged sequentially from proximal to distal; when the connector (3) is in the first position, after the proximal end of the electrode (5) is inserted into the insert (41), the distal end of the electrode (5) extends out of the insulating sheath (2).

9. The high-frequency electrosurgical unit with replaceable electrodes according to claim 8, characterized in that, It also includes a transfer tube, which is fixedly installed inside the handle (1). The transfer tube is used to connect with the outlet of the water pump. The proximal end of the connector (3) is connected to the transfer tube. During the linear movement of the connector (3), the proximal end of the connector (3) is always connected to the transfer tube.

10. The high-frequency electrosurgical unit with replaceable electrodes according to claim 1, characterized in that, The electrode (5) is one of the following: needle electrode, blade electrode, spherical electrode, hook electrode, ring electrode and insulated tip electrode.

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