Endoscopic surgical tools

Abstract

An endoscopic surgical tool comprises: a housing having a proximal end and a distal end, the housing including a central axis and a first hole forming an opening arranged at the distal end; an insulator having a central opening and a second hole, the insulator being configured to extend distally from the housing along the central axis; and a knife arranged within the first hole and including a tip. The knife has a retracted position and an extended position, in which the knife extends distally from the first hole along the central axis, and in which the knife is retracted proximally along the central axis toward the proximal end. The endoscopic surgical tool comprises a force-applying element coupled to the knife, and when the knife is in the extended position, the force-applying element applies a force to the knife toward the retracted position. The endoscopic surgical tool according to the present application allows an operator or surgeon to quickly perform necessary surgery while preventing the knife from inadvertently perforating the GI tract.

Description

[0001] Citation of Related Applications

[0002] This application claims the benefit of and priority to U.S. Provisional Application No. 63 / 154,380, filed on February 26, 2021, the entire contents of which are incorporated herein by reference. Technical Field

[0003] The present invention generally relates to an endoscopic surgical tool for use during endoscopic submucosal dissection, and more particularly, to an endoscopic surgical tool for removing tumors or tissue during endoscopic submucosal dissection. Background Art

[0004] Endoscopic submucosal dissection (ESD) is a procedure to remove a tumor present in a patient's gastrointestinal (GI) tract. Current procedures to remove tumors in the GI tract require the use of a needle-like knife or a knife with an insulator at the end. However, switching between tools during surgery can be cumbersome and increase the length of the surgery, including the time the patient is under anesthesia. In addition, existing knives can include one or more of a surgical instrument with an uninsulated end that provides high-frequency treatment (also known as a needle-like knife) and a surgical instrument with an insulator at the end that provides high-frequency treatment (also known as a knife with an insulator at the end). However, during use, the needle-like knife may protrude from the insulator of the knife, causing perforation of the GI tract or intestine. Summary of the Invention

[0005] Problems to be solved by the invention

[0006] During surgery, prior art needle-like knives may protrude from the insulation of the knife, causing perforation of the GI tract or intestine.

[0007] Solutions for solving problems

[0008] In order to solve the above technical problems, the present invention provides an endoscopic surgical tool, which includes: a shell having a proximal end and a distal end, the shell including a central axis and a first hole forming an opening arranged at the distal end; an insulator including a central opening and a second hole, the insulator being constructed to extend distally from the shell along the central axis; a knife arranged in the first hole and including a tip, the knife having a retracted position and an extended position, wherein, in the extended position, the knife extends distally from the first hole along the central axis, and in the retracted position, the knife retracts proximally along the central axis toward the proximal end; and a force-applying element connected to the knife, and when the knife is in the extended position, the force-applying element applies force to the knife toward the retracted position.

[0009] Preferably, the housing comprises a plate and the force applying element couples the knife to the plate.

[0010] Preferably, the plate includes a plate aperture defining an opening sized and shaped to allow a portion of the knife to pass therethrough.

[0011] Preferably, the force applying element extends along the central axis and includes a first end coupled to the blade and a second end coupled to the plate.

[0012] Preferably, the plate is arranged proximate the proximal end of the housing.

[0013] Preferably, the plate is fixed relative to the rest of the housing and is arranged inside the housing.

[0014] Preferably, the distal end of the insulator comprises a groove extending proximally along the central axis.

[0015] Preferably, the knife comprises a cutting face and a distal portion, the distal portion being arranged between the tip and the cutting face.

[0016] Preferably, the insulator has an extended insulator position in which the insulator extends distally from the housing along the central axis, and the insulator in the extended insulator position causes the blade to be in the extended position.

[0017] Preferably, the knife comprises a shaft arranged between a first cutting edge and a second cutting edge, the first cutting edge having a length greater than the length of the second cutting edge.

[0018] Preferably, the endoscopic surgical tool is configured for use in a needle-like blade configuration and a blade configuration with an insulator at the distal end.

[0019] Preferably, the knife comprises a shaft and at least one cutting portion, the shaft being arranged along the central axis.

[0020] Preferably, the force applying element is a spring.

[0021] Preferably, the housing comprises a substantially flexible material.

[0022] Preferably, the terminal end is an electrode.

[0023] Preferably, the first aperture is sized and shaped to receive the insulator.

[0024] Preferably, the tip of the knife comprises a substantially concave outer surface.

[0025] Preferably, the insulator comprises a substantially concave outer surface.

[0026] The present invention also provides an endoscopic surgical tool, which includes: a housing, which includes a plate arranged near the proximal end and a first hole defining an opening arranged near the distal end, the housing also including a central axis substantially perpendicular to the plate; an insulator, which includes a central opening, a groove, and a second hole, the insulator being constructed to extend distally from the housing along the central axis; a knife, which is arranged in the first hole and includes an end, the knife having a retracted position and an extended position, in the extended position, the knife extends distally from the first hole along the central axis, and in the retracted position, the knife is retracted proximally along the central axis toward the proximal end, the size and shape of the end being made to sit in the groove of the insulator; and a force-applying element, which has a first end and a second end, the first end being connected to the knife and the second end being connected to the plate, and when the knife is in the extended position, the force-applying element applies force to the knife toward the retracted position.

[0027] The present invention also provides an endoscopic surgical tool, which includes: a shell, which includes a single sheath made of a substantially flexible material, the shell also including a plate arranged near the proximal end and a hole defining an opening arranged near the distal end, the shell also including a central axis substantially perpendicular to the plate, the plate including a plate hole; an insulator, which includes a central opening, a groove and an insulator hole, the insulator is configured to extend distally from the shell along the central axis, the insulator having an extended insulator position and a retracted insulator position, the extended insulator position being a condition in which the insulator extends distally from the shell, and the retracted insulator position being a condition in which the insulator is retracted proximally toward the proximal end; a knife, which includes a rod surrounded by a first cutting edge and a second cutting portion, the knife being arranged along The central axis is arranged in the hole, the knife includes an electrode, and the knife has a retracted position and an extended position, wherein in the extended position, the knife extends distally from the hole along the central axis, and in the retracted position, the knife is retracted proximally along the central axis toward the proximal end, the electrode is sized and shaped to be seated in a groove in the insulator, wherein the first cutting edge is arranged to pass through the plate hole and has a length greater than a length of the second cutting portion; and a spring having a first end and a second end, the first end being connected to the rod and the second end being connected to the plate along the central axis, when the knife is in the extended position and the insulator is in the extended insulator position, the spring applies a force to the knife toward the retracted position.

[0028] Effects of the Invention

[0029] In accordance with the present invention, endoscopic surgical tools allow an operator or surgeon to quickly perform necessary procedures while preventing the knife from inadvertently perforating the GI tract. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The following detailed description of embodiments of endoscopic surgical tools will be better understood when read in conjunction with the accompanying drawings of exemplary embodiments. It should be understood, however, that the invention is not limited to the precise arrangements and instrumentalities shown.

[0031] Figures 1A to 1C is an illustration of a prior art endoscopic surgical tool.

[0032] Figures 2A to 2B is an illustration of a prior art endoscopic surgical tool.

[0033] Figure 3 is a cross-sectional view of an exemplary endoscopic surgical tool according to an embodiment of the present invention shown in a partially extended position.

[0034] Figure 4 is shown in the retracted position Figure 3 Cross-sectional view of an endoscopic surgical tool.

[0035] Figure 5 is shown in the extended position Figure 3 Cross-sectional view of an endoscopic surgical tool.

[0036] Figure 6A yes Figures 3 to 5 Side view of an exemplary blade of an endoscopic tool.

[0037] Figure 6B yes Figures 3 to 5 Side view of an exemplary insulator and cutting surface of an endoscopic tool.

[0038] Figure 7A It is intercepted along the AA axis Figure 5 Cross-sectional view of an endoscopic surgical tool.

[0039] Figure 7B It is intercepted along the BB axis Figure 5 Cross-sectional view of an endoscopic surgical tool.

[0040] Figure 8 The operating line is shown Figure 3 Cross-sectional view of an endoscopic surgical tool.

[0041] Figure 9 is a diagram showing additional operating lines Figure 8 Cross-sectional view of an endoscopic surgical tool.

[0042] Figure 10A is shown in knife position Figure 3 Cross-sectional view of an endoscopic surgical tool.

[0043] Figure 10Bis shown in an intermediate state Figure 3 Cross-sectional view of an endoscopic surgical tool.

[0044] Figure 10C is shown as an insulator Figure 3 Cross-sectional view of an endoscopic surgical tool.

[0045] Figure 11A yes Figure 10A Cross-sectional view of an endoscopic surgical tool.

[0046] Figure 11B yes Figure 10A An open stereoscopic view of an endoscopic surgical tool.

[0047] Figure 12A yes Figure 10B Cross-sectional view of an endoscopic surgical tool.

[0048] Figure 12B yes Figure 10B An open stereoscopic view of an endoscopic surgical tool.

[0049] Figure 13A yes Figure 10C Cross-sectional view of an endoscopic surgical tool.

[0050] Figure 13B yes Figure 10C An open stereoscopic view of an endoscopic surgical tool. DETAILED DESCRIPTION

[0051] Reference Figures 1A to 2B Existing endoscopic surgical tools have been used to perform endoscopic submucosal dissection (ESD) and remove tumors. Figures 1A to 1C As shown, a known endoscopic surgical tool 1 may include a sheath 3, a blade 5, and an insulator 11. The insulator 11 includes a hole 9 and the blade 5 may extend through the hole 9 of the insulator 11. The user may use the endoscopic surgical tool 1 in one of two configurations: a needle-like blade configuration ( Figure 1B and Figure 2A ) and a knife structure with an insulator at the end ( Figure 1C and Figure 2B For example, the user can use the endoscopic surgical tool 1 in a needle-like blade configuration, wherein the blade 5 protrudes through the hole 9 of the insulator 11 and the insulator 11 remains within the sheath 3. The needle-like blade configuration can be used for slow and careful surgery to allow for precise cutting and resection. The user can use the endoscopic surgical tool 1 in an insulator-tipped blade configuration, wherein the blade 5 and insulator 11 are fully extended at the distal end of the endoscopic surgical tool 1.

[0052] In some embodiments, the distal end 7 of the blade 5 is disposed within an insulator 11, and the insulator 11 is used to prevent the blade 5 from perforating tissue. A blade configuration with an insulator distal end can be used for rapid surgery. In practice, for example, during rapid dissection, the blade 5 and / or distal end 7 of an endoscopic surgical instrument 1 used in the insulator distal end configuration may inadvertently extend through the insulator 11, resulting in accidental perforation of tissue or the GI tract. For example, when the endoscopic surgical instrument 1 is in the insulator distal end configuration and is used hastily or for rapid dissection, the endoscopic surgical instrument 1 may have an increased risk of GI tract perforation compared to using the endoscopic surgical instrument 1 more slowly in the insulator distal end or needle-like blade configuration. Regardless of how the distal end 7 is moved, the blade 5 may inadvertently extend through the insulator 11 and may perforate tissue or the GI tract. GI tract perforation may cause severe pain, sepsis, internal bleeding, or other injuries.

[0053] Reference Figures 2A to 2B , the endoscopic surgical tool 1 may include a sheath 3. The sheath 3 may include an inner layer 3a and an outer layer 3b. The inner layer 3a may be arranged within the outer layer 3b to provide protection to the blade 5 and provide rigidity to the endoscopic surgical tool 1. The inner layer 3a and the outer layer 3b may also provide a housing for the internal wires and components of the endoscopic surgical tool 1. In some embodiments, the sheath 3 including two layers (the inner layer 3a and the outer layer 3b) causes the endoscopic surgical tool 1 to be substantially rigid, which prevents the endoscopic surgical tool 1 from bending when passing through an endoscope arranged in an inner cavity such as the GI tract. For example, the sheath 3 including two layers (the inner layer 3a and the outer layer 3b) stiffens the endoscopic surgical tool 1, thereby reducing and / or inhibiting bending of the endoscope into which the endoscopic surgical tool 1 is inserted.

[0054] An exemplary embodiment of the present invention provides an endoscopic surgical tool. An embodiment of the present invention provides an exemplary endoscopic surgical tool 200, such as Figures 3 to 9 In use, the endoscopic surgical tool 200 can assist in removing tumors located within the GI tract. Specifically, the endoscopic surgical tool 200 can be used to cut and remove tumors located along the GI tract during procedures such as ESD procedures. The endoscopic surgical tool 200 may include a needle-like blade configuration (also known as a double-blade configuration). Figure 3 ) and also known as insulated tip (IT) blade structure with an insulator at the end ( Figure 5 ).For example, Figure 3 The double-pole structure can be that when the knife is extended, the insulator is still arranged in the housing. Figure 5The blade configuration having an insulator at the distal end can be such that the distal end of the blade is disposed within a recess in the insulator when the insulator and blade are extended away from the housing. The needle-like blade configuration can be used to slowly and precisely remove tissue, such as a tumor, while the blade configuration having an insulator at the distal end can be used to quickly and sweepingly remove tissue or a tumor. For example, compared to a blade configuration having an insulator at the distal end, a needle-like blade configuration without an insulator in the extended position allows an operator or surgeon to visualize a portion of a tumor or tissue that needs to be dissected and removed that is located along the GI tract. The needle-like blade configuration allows the operator or surgeon to slowly dissect the tissue or tumor, which is crucial when bleeding is expected, such as during an ESD procedure.

[0055] In fact, when using the endoscopic surgical tool 200 in the needle-like blade configuration, the operator or surgeon can proceed slowly to prevent the blade from inadvertently perforating the GI tract. In contrast, the blade configuration with an insulator at the distal end allows the operator or surgeon to quickly remove tumors or tissue without worrying about inadvertent perforation of the GI tract. For example, the insulator disposed at the distal end of the blade prevents the blade from inadvertently perforating the GI tract, allowing the operator or surgeon to quickly perform the necessary surgery.

[0056] like Figures 3 to 5 As shown, endoscopic surgical tool 200 may include a housing 202, a blade 204, an insulator 210, a biasing element 216, and a plate 218. Housing 202 may include an imaginary axis, central axis 205, extending along the central length of housing 202. Housing 202 may also include an opening or aperture 219, a proximal end 220, and a distal end 222. Proximal end 220 may be disposed opposite distal end 222. Blade 204 may be disposed within housing 202 along central axis 205 and insulator 210 may be located adjacent to the distal end of blade 204. Blade 204 may be disposed through insulator 210 and may include a tip 206. Insulator 210 and blade 204 may be configured to extend distally along central axis 205 away from housing 202 and opening 219 and to retract proximally along central axis 205 toward housing 202 and opening 219. In some embodiments, the opening 219 is disposed at the distal end 222 and the plate 218 is disposed proximate the proximal end 220 .

[0057] In some embodiments, the knife 204 may include a shaft 212, a cutting surface 207, and a distal portion 211. The knife 204 may include cutting edges 214a and 214b that may surround the shaft 212. In some embodiments, the cutting edges 214a and 214b include the cutting surface 207. In some embodiments, the knife 204, including the distal portion 211 and the cutting surface 207, is configured to cut and / or cauterize tissue. For example, the distal portion 211 and the cutting surface 207 may be configured to be heated or receive an electrical current to cauterize tissue, may include a blade or sharp edge to cut tissue, or may include a laser or other element capable of cutting and / or cauterizing tissue. The cutting surface 207 may be configured to extend from the proximal end of the distal portion 211 to the proximal end, and the distal portion 211 may be disposed between the tip 206 and the cutting surface 207. For example, the shaft 212 and the cutting edges 214a, 214b may extend from the proximal end of the distal portion 211 to the proximal end. However, the distal portion 211 may include a rod 212 and / or cutting edges 214a, 214b. In one embodiment, the distal portion 211 includes an integral cutting edge rather than the rod 212 and cutting edges 214a, 214b. The knife 204 may be configured to extend through the insulator 210 along the central axis 205 via the hole 208. In some embodiments, the insulator 210 is disposed within the housing 202 and is configured to extend distally away from the housing 202 along the central axis 205. For example, the insulator 210 may be disposed adjacent to the distal end 222 of the housing 202 and may be disposed within and extend through the opening 219 of the housing 202. The plate 218 may be disposed within the housing 202 adjacent to the proximal end 220. In some embodiments, the force applying element 216 is configured to couple the knife 204 to the plate 218.

[0058] In some embodiments, the housing 202 can include an opening 219 at the distal end 222. The opening 219 can allow the blade 204 and the insulator 210 to be selectively extended away from the housing 202 along the central axis 205 and retracted into the housing 202. For example, the blade 204 and the insulator 210 can be disposed within the interior 226 of the housing 202 along the central axis 205 and can be configured to extend distally through the opening 219. For example, the blade 204 can have an extended position and a retracted position. In the extended position ( Figure 5 ), the knife 204 can extend distally from the opening 219 along the central axis 205, and in the retracted position ( Figures 3 and 4 ), the blade 204 can be retracted proximally along the central axis 205 toward the proximal end 220. In some embodiments, the insulator 210 has an extended insulator position and a retracted insulator position. In the extended insulator position ( Figure 5 ), the insulator 210 can extend distally from the opening 219 along the central axis 205 and in the retracted position ( Figure 3), the insulator 210 can be retracted proximally along the central axis 205 toward the proximal end 220 and can be arranged within the housing 202.

[0059] In some embodiments, the housing 202 is made of polytetrafluoroethylene (PTFE). However, the housing 202 can be made of other materials, such as polymers, copolymers, rubber or vinyl. The housing 202 can be made of biocompatible materials. In some embodiments, the housing 202 is made of non-conductive materials. The housing 202 can have an inner diameter between about 1.5 mm and about 3.0 mm, an outer diameter between about 1.5 mm and 3.5 mm, a wall thickness between about 0.05 mm and 0.5 mm, and a length between about 500 mm and 3000 mm. In some embodiments, the housing 202 is made of PTFE with a thickness of about 0.45 mm. However, the housing 202 can have a thickness between 0.1 mm and 0.5 mm. In some embodiments, the size and shape of the housing 202 can be set to any desired length. For example, the housing 202 can be longer to allow the endoscopic surgical tool 200 to enter the GI tract more deeply to remove tissue or tumors in the deeper parts of the GI tract.

[0060] In some embodiments, the housing 202 is generally flexible to allow the endoscopic surgical tool 200 to navigate the GI tract. The housing 202 can include a single sheath of non-rigid material that allows the endoscopic surgical tool 200 to bend around the curvature of the GI tract. For example, the housing 202 can include a flexible material that forms a single sheath. However, the housing 202 can include more than one sheath of material. In some embodiments, the housing 202 is coupled to an actuator (not shown) to allow a user or surgeon to control the endoscopic surgical tool 200. The actuator can be configured to extend and retract the blade 204 and the insulator 210. For example, the actuator can be configured to extend one or both of the blade 204 and the insulator 210 and to lock the blade 204 and the insulator 210 into a desired position.

[0061] Reference Figure 3 and Figure 4 , the endoscopic surgical tool 200 may include a blade 204 disposed within a housing 202 along a central axis 205. In practice, when the endoscopic surgical tool 200 is in the needle-like blade configuration ( Figure 3 ) or a knife structure with an insulator at the end ( Figure 5), the blade 204 is utilized. The blade 204 can be used to cut / cauterize desired tissue and / or tumors. For example, the blade 204 can be used to cauterize a tumor found along the GI tract by placing the blade 204 adjacent to the tumor and cauterizing the tumor, allowing the tumor to be peeled off and removed from the GI tract. The endoscopic surgical tool 200 can utilize cauterization to prevent bleeding and hemorrhage within the GI tract. However, the blade 204 can be configured to only cut tissue without cauterizing.

[0062] Reference Figure 3 and Figure 5 , the blade 204 may include a cutting face 207, a distal portion 211, and a tip 206. The tip 206 may be disposed at a distal end of the distal portion 211 of the blade 204 and may have a length between approximately 0.25 mm and 2.5 mm. The distal portion 211 may be disposed adjacent to the tip 206 and may be disposed between the tip 206 and the cutting face 207. The cutting face 207 may be disposed adjacent to the distal portion 211. The distal portion 211 of the blade 204 may be used when the endoscopic surgical tool 200 is in the needle-like blade configuration. When the endoscopic surgical tool 200 is in the needle-like blade configuration, the insulator 210 may remain disposed within the housing 202 and the distal portion 211 may extend through the aperture 208 of the insulator 210, away from the insulator 210 and the housing 202. The distal portion 211 can be extended away from the insulator 210 and the housing 202 so that the tip 206 and the distal portion 211 are exposed, which allows the distal portion 211 to contact and cut / cauterize the desired tissue. In the needle-like blade configuration, the cutting surface 207 can remain disposed within the insulator 210 and the housing 202, while the distal portion 211 and the tip 206 extend out of the housing 202. In the insulator-tipped blade configuration, the tip 206 and the distal portion 211 can be disposed within the insulator 210, which can extend away from the opening 219 and the housing 202. Furthermore, in the insulator-tipped blade configuration, the cutting surface 207 can be exposed to allow the cutting surface 207 to contact and cut / cauterize the desired tissue.

[0063] Reference Figures 3 to 5In some embodiments, the cutting surface 207 is connected to the distal end of the insulator 210. The cutting surface 207 can include a rod 212, which can be surrounded by cutting edges 214a, 214b. The cutting edges 214a, 214b can include blades, wires, sharp corners, conductive materials for cauterization, or other surfaces configured to cut through tissue. The rod 212 can be arranged along the central axis 205 of the housing. The cutting edges 214a, 214b can completely surround the rod 212 along its circumference, such that the cutting edges 214a and 214b form a cylinder around the rod 212 to form the cutting surface 207. The cutting edges 214a, 214b can completely surround the rod 212 to form a smooth and clean cutting and cauterizing surface around the perimeter or circumference of the cutting surface 207. In some embodiments, the cutting edges 214a, 214b can be coupled together circumferentially around the rod 212. 218. However, the cutting face 207 can include a single, integral cutting edge that surrounds the rod 212. The cutting edges 214a, 214b can be coupled or integral so that only one of the cutting edges 214a or 214b needs to be coupled to a wire that provides electrical current to the cutting face 207 and / or the blade 204. In some embodiments, the cutting edge 214a of the cutting face 207 is longer than the cutting edge 214b of the cutting face 207. For example, the cutting edge 214a can extend completely downward for most of the length of the housing 202 and through the plate 218, while the cutting edge 214b can only partially extend downward for the length of the housing 202 and terminate before the plate 218.

[0064] In some embodiments, the cutting surface 207 includes more than two cutting edges. For example, the cutting surface 207 can include three, four, five, six, or more than six cutting edges. In some embodiments where the cutting surface 207 includes more than two cutting edges, each cutting edge can have a portion adjacent to the distal end 222 that is wider than a portion adjacent to the proximal end 220. Each cutting edge 214a, 214b having a wider portion adjacent to the distal end 222 than a narrower portion adjacent to the proximal end 220 allows the cutting surface 207 to have a continuous circumference, preventing gaps from being generated along the circumference or perimeter of the cutting surface 207.

[0065] In some embodiments, cutting edge 214a extends through plate 218 to be connected to a power source in order to provide electric current to cutting edge 214a and / or cutting edge 214b. For example, cutting edge 214a can extend through plate 218 to be connected to a power source, and cutting edge 214a can be electrically connected to cutting edge 214b or contact with cutting edge 214b so that cutting edge 214b is also connected to a power source. In some embodiments, cutting edges 214a, 214b comprise conductive material to allow knife 204 to cauterize tissue. In some embodiments, end 206 is an electrode arranged at the distal end of knife 204 to allow high-frequency current to flow through knife 204, thereby allowing knife 204 to be used for cauterization.

[0066] In a preferred embodiment, the blade 204 comprises stainless steel. For example, the shaft 212 and the cutting edges 214a, 214b may comprise stainless steel. However, the blade 204 may comprise other conductive materials. In some embodiments, the blade 204 is configured to extend from and retract into the housing 202 through the aperture 208 of the insulator 210, which may be disposed within the housing 202. For example, the distal portion 211 of the blade 204 may be configured to partially extend from the housing 202 through the insulator 210. Figure 3 ), the distal portion 211 and the cutting surface 207 can completely extend out of the housing 202 together with the insulator 210 ( Figure 5 ), and when the insulator is disposed adjacent to the opening 219 of the housing 202, the distal portion 211 and the cutting face 207 can be retracted into the insulator 210 ( Figure 4 The distal portion 211 of the knife 204 can partially extend out of the housing 202 so that the endoscopic surgical tool 200 is in a needle-like knife configuration ( Figure 3 ), thereby allowing the distal portion 211 to contact the desired tissue. For example, the blade 204 can be partially extended, thereby allowing the distal portion 211 and the tip 206 of the blade 204 to be exposed to the desired tissue. The distal portion 211 of the blade 204 can partially extend out of the housing 202, while the insulator 210 remains disposed within the housing 202.

[0067] In practice, the operator or surgeon can utilize an actuator (not shown) to control the extension of the blade 204. For example, during use of the endoscopic surgical tool 200 in the needle-blade configuration, the operator or surgeon can engage the actuator to extend the blade 204 so that only the distal portion 211 and the tip 206 extend away from the opening 219 and the housing 202, thereby being exposed. In some embodiments, the tip 206 of the blade 204 extends between 1.5 mm and 2 mm away from the insulator 210 in the needle-blade configuration. Figure 3 ), resulting in a distal portion 211 of between 1.5 mm and 2 mm. For example, in a needle-like blade configuration, the blade 204 may extend only to expose the distal portion 211 and the tip 206, with the cutting surface 207 and the remainder of the blade 204 disposed within the insulator 210, which is disposed within the housing 202. When in the needle-like blade configuration, the distance between the tip 206 and the insulator 210, and therefore the length of the distal portion 211, may be between 0.5 mm and 3 mm, between 0.75 mm and 2.5 mm, and between 1 mm and 2 mm. In some embodiments, the length of the insulator 210 is between 3 mm and 4 mm. However, it may be between 2 mm and 5 mm, between 2.5 mm and 4.5 mm, or between 3 mm and 3.5 mm.

[0068] In some embodiments, the blade 204 is disposed through the insulator 210. The insulator 210 may include a hole 208 defined by an opening and a central aperture 215 disposed along the central axis 205, and the blade 204 may be configured to travel through the central aperture 215 and into and out of the hole 208. For example, the blade 204 may be configured to pass through the hole 208 and the central aperture 215 when extending from and retracting into the housing 202. In practice, when in the needle-like blade configuration, the distal portion 211 of the blade 204 may partially extend beyond the housing 202 and the insulator 210 ( Figure 3 ). In some embodiments, the insulator 210 has a maximum diameter of approximately 5 mm. However, the insulator 210 may have a maximum diameter between 0.5 mm and 5 mm, between 1 mm and 3.5 mm, or between 1.5 mm and 3 mm. In addition, the insulator 210 may have a length of approximately 5 mm. However, the insulator 210 may have a length between 0.5 mm and 5 mm, between 0.75 mm and 3 mm, between 1 mm and 2.5 mm, or between 1.5 mm and 2 mm. In some embodiments, the insulator 210 comprises a non-conductive material such as ceramic. However, the insulator 210 may comprise PTFE, a polymer, a copolymer, rubber, or other non-conductive material. The insulator 210 may be made of an insulating material or may be made of a conductive or non-conductive material with an insulating coating. In some embodiments, the outer surface of the insulator 210 may be substantially smooth to allow the insulator 210 to contact tissue without damaging or causing damage to the tissue.

[0069] In some embodiments, the insulator 210 includes a recess 224. The recess 224 can be sized and shaped to receive the tip 206 when the blade 204 is in the retracted position or when the insulator 210 is distally extended along the blade 204 away from the opening 219. For example, the insulator 210 can be distally extended with the blade 204 locked in a fixed position, causing the insulator 210 to travel distally along the blade 204 and / or along the central axis 205. The recess 224 can be disposed at the distal end of the insulator 210 and can extend proximally from the distal end of the insulator 210 along the central axis 205. In some embodiments, the blade 204 can be in the retracted position and disposed within the insulator 210, which can initially be disposed within the housing 202. For example, the tip 206 can be disposed within the recess 224 such that when the insulator 210 is distally extended, the tip 206 and the blade 204 also extend distally.

[0070] Reference Figures 3 to 5, the radius of the groove 224 can be greater than the radius of the tip 206 and the depth can be greater than the length of the tip 206. For example, the tip 206 can have a radius between approximately 0.25 mm and 1.5 mm and a length between approximately 0.10 mm and 0.5 mm. In some embodiments, the groove 224 has a depth of approximately 0.5 mm or greater. For example, the groove 224 can have a depth between 0.2 mm and 2.5 mm, between 0.5 mm and 2 mm, or between 1 mm and 1.5 mm, or greater than 0.5 mm. The groove 224 can be configured to prevent the blade 204 from further retracting into the housing 202 by preventing the tip 206 from moving proximally once the tip 206 is disposed within the groove 224. For example, the diameter of the groove 224 can be greater than the central opening 215, thereby preventing the tip 206 from retracting proximally past the groove 224. In some embodiments, the tip 206 of the blade 204 is disposed within the recess 224 and the insulator 210 is extended distally, such that the insulator 210 distally pushes the tip 206 and the blade 204. For example, when the tip 206 of the blade 204 is disposed within the recess 224, the extension of the insulator 210 may cause the blade 204 to extend due to the insulator 210 pushing against the tip 206 of the blade 204. The placement of the tip 206 within the recess 224 may cause the distal portion 211 to be positioned with the central opening 215. For example, in a blade configuration with an insulator at the tip, when the insulator 210 is extended distally away from the housing 202, the tip 206 may be disposed within the recess 224 and the distal portion 211 may be disposed within the central opening 215 of the insulator 210, resulting in the cutting surface 207 being exposed and able to contact the desired tissue.

[0071] Reference Figure 6A and Figure 6B , the size and shape of the insulator 210 can be made to accommodate a portion of the blade 204. For example, the distal portion 211 of the blade 204 can be disposed within and extend through the central opening 215 of the insulator 210. In some embodiments, the distal portion 211 has a diameter D1 and the shaft 212 has a diameter D2. The diameter D1 can be between approximately 0.2 mm and 0.8 mm, and the diameter D2 can be between approximately 0.05 mm and 0.5 mm. The diameter D1 can be larger than the diameter D2. The diameter D1 can be approximately 0.4 mm. However, the diameter D1 can be between 0.1 mm and 2 mm, between 0.3 mm and 0.6 mm, or between 0.5 mm and 1 mm. In some embodiments, the diameter D1 of the distal portion 211 is the same as the diameter of the cutting surface 207. In some embodiments, the diameter D2 of the shaft 212 plus the thickness of the cutting edges 214a, 214b is equal to the diameter D1. Figure 6B, the central opening 215 can have a diameter D3, which can be larger than diameter D1. For example, diameter D3 can be larger than diameter D1 by delta Δ. Diameter D3 can be between approximately 0.25 mm and 0.75 mm. In some embodiments, the endoscopic surgical tool 200 has a diameter D4. Diameter D4 can be equal to diameter D2 plus delta Δ to ensure that there is sufficient space for the cutting face 207 to move longitudinally along the central axis 205 through the central opening 215. For example, diameter D4 can be smaller than diameter D3 of the central opening 215. In some embodiments, diameter D4 is between approximately 0.05 mm and 0.5 mm. In some embodiments, delta Δ is between approximately 0.01 mm and 0.05 mm. Delta Δ can allow clearance between the cutting face 207 and the interior of the central opening 215 to allow for the addition of, for example, an adhesive (such as glue or adhesive) at its natural length when the insulator 210 is in the retracted position. When the insulator 210 is in the extended insulator position, the force applying element 216 can become extended. In the extended position, the force applying element 216 provides a biasing force on the blade 204 and the tip 206, pulling the blade 204 and the tip 206 toward the proximal end 220.

[0072] In an alternative embodiment, the rod 212 can extend through the plate 218 and the force applying element 216 can be coupled to the proximal side 243 of the plate 218 such that the force applying element 216 is coupled to the rod 212 adjacent the proximal side 243 of the plate 218. For example, the force applying element 216 can be coupled to the proximal side 243 of the plate 218 such that the force applying element 216 extends to the proximal end 220 and is configured to urge the rod 212 toward the proximal end 220. The force applying element 216 being coupled to the proximal side 243 of the plate 218 and configured to urge the rod 212 toward the proximal end 220 can prevent the blade 204 and the tip 206 from inadvertently extending through the insulator 210.

[0073] Reference Figures 3 to 5 , the endoscopic surgical tool 200 can be configured to be in a needle-like knife configuration ( Figure 3 ) and a knife structure with an insulator at the end ( Figure 5 ). When the distal portion 211 and the tip 206 of the blade 204 extend out of the insulator 210 and away from the opening 219, the endoscopic surgical tool 200 can be in the needle-like blade configuration. For example, the needle-like blade configuration can be when the blade 204 extends distally from the opening 219 while the insulator 210 is still disposed within the housing 202. In the needle-like blade configuration, the distal portion 211 of the blade 204 is prevented from retracting into the housing 202 via an actuator (not shown). In practice, in order to move from the needle-like blade configuration ( Figure 3 ) to the end with an insulator blade structure ( Figure 5), an actuator (not shown) is used to extend the insulator 210. The insulator 210 can be extended away from the opening 219 so that the tip 206 of the knife 204 becomes arranged in the groove 224 of the insulator, as shown in FIG. Figure 4 As shown in FIG. 2 , the tip 206 can contact and become disposed within the groove 224 because the insulator 210 extends away from the opening 219 and the housing 202 without the distal portion 211 of the blade 204 extending or retracting, causing the groove 224 of the insulator 210 to contact the tip 206. As the insulator 210 continues to extend distally away from the opening 219, the insulator 210 pushes the tip 206 distally away from the opening 219, causing the blade 204 to extend distally together with the insulator 210, as shown in FIG. Figure 5 shown.

[0074] In some embodiments, the force-applying element 216 applies a biasing force to the tip 206 and blade 204 such that the tip 206 remains in the recess 224 when the insulator 210 is extended away from the opening 219 and the housing 202. For example, the biasing force of the force-applying element 216, which pulls the tip 206 toward the proximal end 220, acts in opposition to the force of the insulator 210, which extends the tip 206 distally away from the opening 219. In some embodiments, when the insulator 210 is distally extended, the biasing force of the force-applying element 216 is less than the force of the insulator 210 on the tip 206, allowing the insulator 210 to extend distally while the tip 206 is still being forced toward the proximal end 220. The insulator 210 can be locked in the extended position during use, and the biasing force of the force-applying element 216 on the tip 206 of the blade 204 causes the tip 206 to be drawn into the recess 224, thereby preventing the tip 206 and blade 204 from being inadvertently extended.

[0075] In some embodiments, when the insulator 210 is extended away from the opening 219 to be in the locked and extended position, the force-applying element 216 coupled to the plate 218 and the rod 212 becomes extended. The extension of the force-applying element 216 causes a biasing force to pull the rod 212 toward the proximal end 220. The biasing force of the force-applying element 216 pulling the rod 212 toward the proximal end 220 causes the tip 206 of the blade 204 to remain within the recess 224.

[0076] Reference Figures 3 to 5 as well as 7A to 7B, the force-applying element 216 can be coupled to a plate 218. The plate 218 can comprise a hard or rigid material, such as metal, steel, resin, or polymer. The plate 218 can be circular and disposed within the interior 226 of the housing 202. However, the plate 218 can be rectangular, oval, square, triangular, semicircular, or any other desired shape. In some embodiments, the plate 218 has a diameter substantially the same as the inner diameter of the housing 202. In some embodiments, the plate 218 extends around the entire inner circumference of the housing 202 and can have a diameter smaller than the outer diameter of the housing 202. However, the plate 218 may extend around only a portion of the inner circumference of the housing 202. For example, the plate 218 may extend only between 10° and 345°, between 45° and 300°, between 90° and 270°, between 120° and 225°, or between 180° and 200°. The plate 218 can be disposed within the housing 202 such that the plate 218 is substantially perpendicular to the central axis 205. In some embodiments, the plate 218 has a thickness between approximately 0.5 mm and 5 mm. The thickness of the plate 218 can be sized so as not to interfere with the bending of the endoscopic surgical tool 200. In some embodiments, the plate 218 is configured to secure and stabilize the cutting surface 207, including the rod 212 and the cutting edges 214a, 214b, thereby preventing unintentional lateral movement.

[0077] In some embodiments, the plate 218 includes a plate opening or plate hole 230. The plate 218 can include more than one plate opening 230. For example, the plate 218 can include two, three, four, five, or six plate openings 230 arranged around the plate 218. In some embodiments, the plate 218 can include more than one plate opening 230 to allow multiple cutting edges to extend through the plate 218. In some embodiments, the endoscopic surgical tool 200 includes multiple cutting edges and more than one cutting edge can be arranged to extend through more than one plate opening 230. In some embodiments, the plate 218 can have more than one plate opening 230 and each plate opening 230 can be equidistant from an adjacent plate opening 230.

[0078] In some embodiments, the plate opening or plate hole 230 is sized and shaped to allow more than one cutting edge 214a, 214b to pass through the plate 218. In a preferred embodiment, the plate 218 only allows one of the cutting edges 214a or 214b to pass through to allow the force applying element 216 to couple to the plate 218. For example, allowing both cutting edges 214a, 214b, each spanning halfway around the plate 218, to pass through the plate 218 would result in a hole along the central axis 205 at point 231 where the force applying element 216 couples to the plate 218. Therefore, to allow the force applying element 216 to couple to the plate 218 at point 231, the plate 218 includes only one plate opening 230 configured to allow one of the cutting edges 214a or 214b to pass through the plate 218. However, the plate 218 may include a plurality of plate openings 230 configured to allow a plurality of cutting edges to be disposed through the plate while still maintaining points 231 for coupling the force applying element 216 to the plate 218 .

[0079] In some embodiments, the length of cutting edge 214a is greater than cutting edge 214b to allow cutting edge 214a to extend through the plate opening 230 of plate 218. For example, the length of cutting edge 214b can be between about 2mm and about 5mm, and the length of cutting edge 214a can be between about 4mm and about 10mm. The size and shape of plate opening 230 can be made to allow cutting edge 214a or 214b to pass through. For example, the shape of plate opening 230 can be semicircular. However, plate opening 230 can be rectangular, triangular, oval or any other desired shape. In some embodiments, plate opening 230 is arranged on plate 218 away from central axis 205. In some embodiments, plate opening 230 extends around plate 218 less than 360 °. For example, the plate opening 230 can extend between 10° and 345°, between 45° and 300°, between 90° and 270°, between 120° and 225°, or between 180° and 200° around the plate 218. In some embodiments, the plate opening 230 extends between 30° and 330° around the plate 218. The plate opening 230 can have a length sized and shaped to receive one of the cutting edges 214a or 214b. In some embodiments, the length of the plate 218 is between approximately 0.01 mm and 0.05 mm.

[0080] Reference Figure 7A and Figure 7B , a cross-sectional view of an endoscopic surgical tool 200 is shown. Figure 7A Shown along Figure 5 A cross-sectional view of the plate 218 taken along the AA axis, Figure 7B Shown along Figure 5FIG20 is a cross-sectional view of plate 218 taken along the BB axis. The AA axis is adjacent to opening 219 and distal end 222, and the BB axis is adjacent to point 231 and proximal end 220, where force-applying element 216 is coupled to plate 218. At the AA axis, both cutting edges 214a and 214b are present. However, at the BB axis and adjacent to point 231, cutting edge 214b is no longer present to allow force-applying element 216 to couple to point 231. If both cutting edges 214a and 214b were to pass through plate opening 230, then because cutting edges 214a and 214b form a cylinder around rod 212, cutting edges 214a and 214b would form a hole at point 231. This would prevent force-applying element 216 from coupling to plate 218 at point 231.

[0081] Reference Figure 8 , the endoscopic surgical tool 200 may include a wire that provides current to the blade 204. Figure 8 In one embodiment shown, the endoscopic surgical tool 200 can include a single operating wire 234. The operating wire 234 can be welded to the cutting edge 214a via a weld 232. The operating wire 234 can be configured to supply current from a power source (not shown) through the cutting edge 214a to the cutting edge 214b to allow current to flow through the knife 204, enabling the knife 204 to cut and burn tissue. In some embodiments, the cutting surface 207 is connected to the distal end of the operating wire 234. The operating wire 234 can be configured to provide current to the knife 204, regardless of whether the endoscopic surgical tool 200 is in a needle-like knife configuration or a knife configuration with an insulator at the end.

[0082] In some embodiments, as Figure 9 As shown, the endoscopic surgical tool 200 may include more than one operating wire. For example, the endoscopic surgical tool 200 may include an operating wire 236 and an operating wire 238. The operating wire 236 may be coupled to the cutting edge 214a to provide current from a power source (not shown) to the cutting face 207 through the cutting edge 214a. In addition, the operating wire 238 may be coupled to the plate 218 and may be configured to provide current to one or more of the cutting face 207 and the distal portion 211 via, for example, the force applying element 216. However, the endoscopic surgical tool 200 may include as many operating wires as desired. For example, the endoscopic surgical tool 200 may include three, four, five, six, seven, eight, or more than eight operating wires.

[0083] Reference Figure 3 as well as 10A to 13BThe endoscopic surgical tool 200 may include a second insulator 240. The second insulator 240 may include an inner surface 240a and an outer surface 240b, and may have a proximal end 240c and a distal end 240d. The proximal end 240c of the second insulator 240 may be inside the housing 202. The distal end 240d of the second insulator 240 may be adjacent to or flush with the distal end 222 of the housing 202. The inner surface 240a of the second insulator 240 may have a cross-section with a smaller diameter at the distal end 240d than at the proximal end 240c.

[0084] The endoscopic surgical tool 200 may further include a connecting element 242 and one or more protrusions 244. The connecting element 242 may surround the force applying element 216 and may be inserted into the inner surface 240a of the second insulator 240.

[0085] 10A to 13B The structure allows switching between the above-mentioned needle-like knife structure ("knife state") and the structure of the knife 204 with the insulator 210 at the tip 206 ("insulator state") by advancing and retracting the operating wire 234. Figure 10A The knife state is shown, wherein the operating wire 234 is fully retracted and the force applying element 216 is in a balanced state. Figure 10B An "intermediate state" between the blade state and the insulator state is shown. Figure 10C The insulator state at the end is shown. Figure 10C In the insulator state shown, the operating wire 234 is fully extended and the force applying element 216 is in a compressed state.

[0086] exist Figure 10A as well as Figures 11A to 11B In the example of the knife state shown in FIG, the treatment tool 200 can be used in a needle-like knife configuration. The insulator 210 can be connected to the distal end of the cutting surface 207. The proximal end of the cutting surface 207 can be connected to the proximal end of the connecting element 242. The connecting element 242 can be connected to the operating wire 234. The circumferential surface of the connecting element 242 may include one or more elongated openings 242a corresponding to the one or more protrusions 244. The interior of the connecting element 242 can accommodate the force-applying element 216. The proximal end of the force-applying element 216 can be connected to the interior of the connecting element 244.

[0087] exist Figure 10B and 12A to Figure 12B In the intermediate state shown in the example, the operating wire 234 can be partially advanced / retracted. The force applying element 216 can be in a balanced state. One or more protrusions 244 can contact the proximal end 240c of the second insulator 240. The insulator 210 can be separated from the distal end 240d of the second insulator 240. Figure 10B as well as FIG. 12A to FIG. 12BThe example shows that the operating wire 234 can advance until the one or more protrusions 244 contact the proximal end 240c of the second insulator 240. The diameter of the proximal end of the through hole in the second insulator 240 (for example, the diameter of the inner surface 240a adjacent to the proximal end 240c of the second insulator 240) can be smaller than the one or more protrusions 244, thereby providing an upper internal obstruction portion 240e. Therefore, when the operating wire 234 advances, after the one or more protrusions 244 contact the proximal end 240c of the second insulator 240, the one or more protrusions 244 may not advance further. Therefore, the knife 204 may not advance further. However, by moving the one or more protrusions 244 through the opening 242a provided in the connecting element 242, the connecting element 242 can advance further.

[0088] If the operating line 234 is Figure 10B as well as FIG. 12A to FIG. 12B The intermediate state shown is moved forward. The insulator state can be achieved, such as Figure 10C as well as 13A to 13B As shown in the example of . When the operating wire 234 advances, the connecting element can advance until the distal end of the connecting element 242 contacts the narrowed portion of the inner surface 240a of the second insulator 240 near the distal end 240d of the second insulator 240 at the upper internal obstruction 240e. The contact at the upper internal obstruction 240e prevents the connecting element 242 from being pushed out of the distal end 240d of the second insulator 240, and the cutting edge 207 and the insulator 210 can continue to advance. When the connecting element 242 advances, the cutting edge 207 and the insulator can also advance until the force applying element 216 is in a compressed state. Therefore, the insulator 210 can advance further than the knife 204. Therefore, the end 206 can be enclosed within the groove 224 and laterally surrounded by the insulator 210. Figure 10C as well as 13A to 13B In the insulated state shown, the treatment tool 200 can be used as a blade 204 having a distal end 206 having an insulator 210 .

[0089] The treatment tool 200 can be reversed 10A to 13B The operation shown in FIG. 200 and being changed to the knife state from being in the insulating state. Reverse operation can be realized by at least retracting the operating wire 234 until the operating wire 234 is in the equilibrium length. Therefore, the disposal tool 200 can move from the insulating state to the intermediate state, and then move to the knife state.

[0090] Those skilled in the art will appreciate that changes may be made to the exemplary embodiments shown and described above without departing from the broad inventive concept thereof. Therefore, it will be understood that the invention is not limited to the exemplary embodiments shown and described, but is intended to cover variations within the spirit and scope of the invention as defined by the claims. For example, certain features of the exemplary embodiments may or may not be part of the claimed invention, and various features of the disclosed embodiments may be combined. The words "near," "far," "above," and "below" indicate directions in the accompanying drawings to which reference is made. Unless otherwise specified herein, the terms "a" and "the" are not limited to one element, but are to be understood to mean "at least one."

[0091] It should be understood that at least some of the drawings and descriptions of the present invention have been simplified to focus on elements relevant to a clear understanding of the present invention, while other elements that may also form part of the present invention and that will be understood by those of ordinary skill in the art have been eliminated for the purpose of clarity. However, because these elements are well known in the art and because they do not necessarily contribute to a better understanding of the present invention, a description of these elements is not provided herein.

Claims

1. An endoscopic surgical tool comprising: a housing having a first aperture extending along a longitudinal axis of the housing; an insulator configured to extend distally from the housing along a longitudinal axis of the housing; a knife extending through the first aperture and having a tube with a cutting surface at an outer surface of the tube, at least a portion of the tube being configured to protrude from the housing; a rod disposed within the tube and configured to move relative to the tube along a longitudinal axis of the housing; a wire extending along a longitudinal axis of the housing and having a distal end and a proximal end; a connector coupling a distal end of the wire to the tube; and a spring disposed between the proximal end of the rod and the connector and extending along the longitudinal axis of the housing, Wherein, when the connector is advanced, the tube and the insulator can be advanced until the spring is in a compressed state.

2. The endoscopic surgical tool according to claim 1, wherein The insulator is coupled to the tube.

3. The endoscopic surgical tool according to claim 2, wherein: The rod has an enlarged tip at a distal end of the rod, and a portion of the tube configured to protrude from the housing extends from the distal end of the housing toward the enlarged tip.

4. The endoscopic surgical tool according to claim 3, wherein: The insulator includes a groove at a distal end of the insulator, and the groove is sized and shaped to receive the enlarged tip.

5. The endoscopic surgical tool according to claim 3, wherein: The insulator has a first lumen, and the enlarged tip is movable within the first lumen in a longitudinal direction of the blade.

6. The endoscopic surgical tool according to claim 5, wherein: The housing has a second insulator at a distal end of the housing, The second insulator has a second inner cavity, and The tube is movable within the second lumen in a longitudinal direction of the knife.

7. The endoscopic surgical tool according to claim 6, wherein: The enlarged tip is configured to be received in the first lumen with the enlarged tip contacting the distal end of the tube.

8. The endoscopic surgical tool according to claim 2, wherein: The first aperture is sized and shaped to receive the insulator.

9. The endoscopic surgical tool according to claim 8, wherein The knife has a retracted position and an extended position, In the extended position, the knife extends distally from the first aperture, and in the retracted position, the knife is retracted proximally relative to the first aperture, and The spring urges the knife toward the proximal end of the housing when the knife is in the extended position.

10. The endoscopic surgical tool according to claim 1, wherein The rod has an enlarged tip at a distal end of the rod.

11. The endoscopic surgical tool according to claim 10, wherein: The tube has a distal end connected to the insulator, and the distal end of the tube is disposed between the enlarged tip and the distal end of the tube.

12. The endoscopic surgical tool according to claim 1, wherein At least a portion of the connector is formed in a tubular shape, and the spring is located inside the connector.

13. The endoscopic surgical tool according to claim 1, wherein The knife is configured to move relative to the housing along a longitudinal axis of the housing.

14. The endoscopic surgical tool according to claim 1, wherein The housing comprises a substantially flexible material.

15. The endoscopic surgical tool according to claim 1, wherein The blade is an electrode.

16. The endoscopic surgical tool according to claim 1, wherein the insulator is coupled to the tube, The rod has an enlarged tip at a distal end of the rod, and When the enlarged tip contacts the distal end of the tube, the outer peripheral surface of the enlarged tip is covered by the insulator.

17. An endoscopic surgical tool comprising: a housing comprising a single sheath formed of a substantially flexible material, the housing further comprising a plate disposed proximate a proximal end and an aperture defining an opening disposed proximate a distal end, the housing further comprising a central axis substantially perpendicular to the plate, the plate including the plate aperture; an insulator comprising a central opening, a groove, and an insulator hole, the insulator being configured to extend distally from the housing along the central axis, the insulator having an extended insulator position and a retracted insulator position, the extended insulator position being a condition in which the insulator is distally extended from the housing, and the retracted insulator position being a condition in which the insulator is proximally retracted toward the proximal end; a knife comprising a shaft surrounded by a first cutting edge and a second cutting portion, the knife being disposed within the aperture along the central axis, the knife including an electrode, and the knife having a retracted position and an extended position, wherein in the extended position the knife is distally extended from the aperture along the central axis, and in the retracted position the knife is proximally retracted along the central axis toward the proximal end, the electrode being sized and shaped to seat within the recess of the insulator, wherein the first cutting edge is disposed through the plate aperture and has a length greater than a length of the second cutting portion; and a spring having a first end coupled to the rod and a second end coupled to the plate along the central axis, the spring urging the knife toward the retracted position when the knife is in the extended position and the insulator is in the extended insulator position.

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