Tether cutting device and method

Abstract

Devices and methods for cutting tethers are described herein. Devices described herein generally include a proximal handle, a catheter, an inner shaft, and a cutting blade disposed within a lumen of the catheter, wherein the cutting blade is movably disposed on the inner shaft. The proximal handle includes an actuation mechanism that controls movement of the device component. The methods described herein generally include advancing a tether cutting device on a tether, loading the tether through a catheter and an inner shaft, applying tension to the tether, and rotating and distally translating a cutting blade to cut the tether.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority to U.S. Provisional Patent Application No. 62 / 874,279, filed on July 15, 2019, the entire contents of which are incorporated herein by reference. Technical Field

[0002] The devices and methods described herein generally relate to the termination of a tether that has been deployed to a target site within a subject. More specifically, the devices and methods described herein relate to cutting such a tether after the tether has been secured. Background Art

[0003] Many types of medical procedures involve the use of tethers. For example, a tether can be used to bring two or more tissue regions together. The tether can then be fixed to maintain the compression or tension applied by the tether to the tissue region, and additional tethers can be cut or removed. However, it can be difficult to consistently cut the tether because the tether often needs to be cut at or near the target site in the subject's body, and the tethers used to fix the tissue are usually very strong. Current devices and methods for cutting tethers are often unreliable and may not completely cut the tether, or may cut the tether prematurely before the device is positioned. In addition, some devices or methods may cut the tether at more than one point, resulting in the formation of loose pieces of tether.

[0004] Therefore, it would be desirable to provide a device that can be easily and effectively placed at a target site, and a method to effectively cut a tether after the tether has been deployed and secured at the target site. It would be further desirable that such a method and device be efficient and reliable, and have a way to protect the tether from being cut before the operator is ready. In addition, it would be desirable that the device and method cut the tether in only one place, avoiding the need for the additional step of retrieving loose pieces of tether. Summary of the invention

[0005] Devices and methods for cutting tethers are described herein, such as tethers that have been used to tighten or compress tissue (e.g., by pulling two or more tissue sections or blocks together). Devices described herein generally include a catheter, an inner shaft, and a cutting blade. The inner shaft can be coaxial with the cutting blade, and both the inner shaft and the cutting blade can be coaxially arranged in the catheter lumen. For example, the inner shaft can be arranged in the lumen of the catheter, and the cutting blade can be arranged on the inner shaft. The catheter can include a proximal end, a distal end, a lumen passing therethrough, and a sidewall, wherein the sidewall includes a first opening and a second opening located distally of the first opening. The lumen of the catheter can terminate in a distal opening. The inner shaft can include a proximal end, a distal end, and a shaft lumen passing therethrough, wherein the inner shaft is arranged in the catheter lumen, proximal to the first opening. The cutting blade can be arranged on the inner shaft, and an actuating mechanism can be coupled to the cutting blade, and is configured to rotate and translate the cutting blade around the inner shaft.

[0006] In some variations, the inner shaft may be stationary within the lumen of the catheter. In other variations, the inner shaft may be movable within the lumen of the catheter. A lead screw may be coupled to the inner shaft, wherein rotation of the lead screw translates the inner shaft. An actuation mechanism may be coupled to the lead screw such that moving the actuation mechanism rotates the lead screw. In some variations, a gear mechanism may be coupled to the inner shaft, wherein rotation of the gears rotates and / or translates the inner shaft. In some variations, the distal end of the inner shaft may be blunt.

[0007] The tether cutting device described herein may also include a first configuration and a second configuration, in which the distal end of the blade is located proximal to the distal end of the inner shaft, and in the second configuration, the distal end of the blade is located distal to the distal end of the inner shaft. The device may include an actuating mechanism that is configured to move the blade between the first and second configurations to cut the tether. In some variations, the tether may extend across a portion of the catheter lumen into the lumen of the inner shaft. For example, a tether extending from the second opening, passing through the first opening and passing through the shaft lumen may partially extend across the lumen of the catheter. The cutting blade may rotate and translate longitudinally on the inner shaft to cut the tether. In some variations, the blade may be tubular.

[0008] The tether cutting device described herein may also include a proximal handle. The proximal handle may include an actuating mechanism to move the blade, for example, between the first and second configurations. The actuating mechanism may include a lead screw coupled to the blade, wherein rotation of the screw causes the blade to rotate and translate longitudinally. For example, the actuating mechanism may be configured to slide the blade along the length of the catheter at the same time and rotate the blade around the longitudinal axis of the catheter. In some variations, the actuating mechanism may be configured to move the blade bidirectionally distally and proximally within the catheter. In some variations, the blade may be held within the lumen of the catheter by the actuating mechanism.

[0009] Also described herein is a method for cutting a tether. The method may include advancing a tether cutting device on the tether, applying tension to the tether, and simultaneously rotating and translating a cutting blade of the tether cutting device distally to cut a portion of the tether that extends partially across the catheter lumen of the tether cutting device. In some variations, advancing the tether cutting device on the tether may also include loading the tether into various components of the device. The tether cutting device advanced on the tether may include a catheter, an inner shaft, and a cutting blade disposed on the inner shaft. The catheter may include an inner lumen and a sidewall, wherein the sidewall may include a first opening and a second opening distal to the first opening. The inner shaft may include an inner lumen of the shaft, and the inner shaft may be disposed within the inner lumen of the catheter. The device may also include a cutting blade disposed on the inner shaft. In some variations, the blade and the inner shaft may be coaxial. In some variations, the tether may extend from the second opening, pass through the first opening, and pass through the inner lumen of the shaft, so that a portion of the tether extends partially across the inner lumen of the catheter. In some variations, simultaneously rotating and translating the blade distally includes actuating an actuating mechanism coupled to the cutting blade. The actuation mechanism may be in the proximal handle. Rotating and distally translating the blade may include moving the blade from a first position to a second position.

[0010] The methods described herein may also include translating the blade proximally. In some variations, the method of cutting the tether may further include actuating the blade to move from a first position to a second position, wherein the distal end of the blade is located proximally of the distal end of the inner shaft, and in the second position, the distal end of the blade is located distally of the distal end of the inner shaft. In some variations, the blade may remain in the first position until actuated using an actuating mechanism. The method may also include adjusting the angle of the tether before cutting the tether. The tether extending from the first opening into the shaft lumen forms an angle relative to the longitudinal axis of the shaft lumen. The method may include adjusting the angle to a first preselected angle value before the tether cutting device is advanced on the tether, and adjusting the angle to a second preselected angle value before cutting the tether. In some variations, the second preselected angle value may be greater than the first preselected angle value. Adjusting the angle to the first preselected angle value may include translating the inner shaft proximally. Adjusting the angle to the second preselected angle value may include translating the inner shaft distally. In some variations of the methods described herein, the tether is a component of a cardiac implant that has been secured in the heart at an implantation site, and the method of cutting the tether can further include advancing a tether cutting device to the implantation site. The implant can be a valve repair device that includes an anchor secured to tissue and coupled to the tether. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] The drawings are primarily for illustrative purposes and are not intended to limit the scope of the inventive subject matter described herein. The drawings are not necessarily drawn to scale; in some cases, various aspects of the inventive subject matter disclosed herein may be exaggerated or enlarged in the drawings to facilitate understanding of different features. In the drawings, like reference numerals generally refer to like features (e.g., functionally similar and / or structurally similar elements).

[0012] Figure 1A and 1B A schematic representation of a variation of a tether cutting device is depicted; Figure 2A and 2B A variation of the tether cutting device is depicted; Figure 3A and 3B depicts a schematic side cross-sectional view of a variation of a tether cutting device; Figure 3C Depicted along Figure 3A A schematic front cross-sectional view of a variation of the tether cutting device taken along line 3C-3C; Figures 4A-4C depicts a perspective view of components of a variation of a tether cutting device; Figure 5A depicting a perspective view of a proximal handle of a tether cutting device; Figure 5B and 5C depicts a side partial cross-sectional view of components of a variation of a tether cutting device; Figure 5D-5G depicts a perspective view of components of a variation of a tether cutting device; Figure 6 A flow chart representation of a variation of a method for cutting a tether is depicted. DETAILED DESCRIPTION

[0013] The following description is not intended to limit the apparatus and methods described herein to these variations. The variations, configurations, implementations, example implementations, and examples described herein are optional and do not exclude the variations, configurations, implementations, example implementations, and examples they describe. The apparatus and methods described herein may include any and all permutations of these variations, configurations, implementations, example implementations, and examples.

[0014] Devices and methods for cutting tethers are described herein. A variation of a tether cutting device may include a catheter, an inner shaft, and a cutting blade. The inner shaft and the cutting blade may be coaxially arranged in the catheter lumen. The cutting blade may be movably arranged around the inner shaft (e.g., may be longitudinally translated and / or rotated on the inner shaft). The inner shaft may include a longitudinal lumen and may extend from a distal portion of the catheter to a proximal handle. In some variations, the tether may extend into the lumen of the inner shaft across a portion of the catheter lumen. For example, the tether may extend from an opening in the catheter sidewall into the lumen of the inner shaft and extend through the length of the inner shaft lumen to the proximal handle. When the device is advanced to a desired cutting position on the tether, the inner shaft may protect the tether from the influence of the cutting blade. The cutting blade may be capable of rotating and longitudinally translating on the inner shaft so as to contact and cut the tether. The simultaneous translation and rotation of the cutting blade may produce a shearing or cutting effect on the tether, which may promote consistent and reliable cutting of the tether. In some variations, a proximal handle of the tether cutting device may be coupled to the catheter, inner shaft, and proximal end of the cutting blade.

[0015] A variation of the method for cutting a tether may include passing the tether through a tether cutting device so that the tether extends from an opening in the catheter sidewall into the lumen of an inner shaft disposed within the catheter lumen, and simultaneously rotating and translating a cutting blade disposed on the inner shaft to contact and cut the portion of the tether extending between the sidewall opening and the inner shaft lumen. In some variations, the method may include advancing the tether cutting device on the tether and keeping the tether under tension before cutting the tether. Optionally, in some variations, the inner shaft may move proximally within the catheter lumen, which may help reduce the catheter tracking force and facilitate the advancement of the catheter. The method may also include using an actuating mechanism to control the translation and rotation of the cutting blade to cut the tether. The simultaneous translation and rotation of the cutting blade may allow the cutting blade to apply a shear force to cut the tether, which may facilitate reliable cutting of the tether. The cutting blade may translate so that it moves from a first position to a second position, in which the distal end of the cutting blade is proximal to the distal end of the inner shaft, and in which the distal end (e.g., a sharp edge) of the cutting blade is distal to the distal end of the inner shaft. Optionally, in some variations, the inner shaft can be advanced distally (e.g., closer to but preferably not distal to the proximal-most opening in the catheter sidewall), which can provide a more effective cutting angle between the tether and the cutting blade prior to translating the cutting blade to contact the tether.

[0016] Device The tether cutting device described herein generally includes a proximal handle attached to a catheter assembly, which includes a catheter, an inner shaft and a cutting blade. The inner shaft and the cutting blade can be coaxially arranged in the inner cavity of the catheter. The proximal handle can include one or more actuating mechanisms, which are configured to control the movement of various components of the device (such as a cutting blade and / or an inner shaft). The cutting blade can be movably arranged on the inner shaft in the catheter lumen. The actuating mechanism can allow the operator to rotate and translate the cutting blade around the inner shaft at the same time. The inner shaft can be configured to protect the tether from being cut by the catheter. When the cutting blade is in a first position, wherein the sharp portion of the cutting blade is near the distal end of the inner shaft, the inner shaft can hold the tether on the distal side of the sharp portion so that the tether will not be cut. In order to cut the tether, the operator can actuate the cutting blade to move the cutting blade to a second position, in which the sharp portion of the cutting blade is distal to the distal end of the inner shaft. When the cutting blade moves from the first position to the second position, the cutting blade can contact and cut the tether.

[0017] Figure 1AA schematic diagram of a variation of a tether cutting device (100) is depicted. The tether cutting device (100) may include a proximal handle (102) attached to a catheter assembly (110), the catheter assembly including a catheter (104), an inner shaft (106), and a cutting blade (108). The cutting blade (108) and the inner shaft (106) are coaxially disposed within the lumen of the catheter (104). The tether may extend across a portion of the catheter lumen, for example, from an opening in the side wall of the catheter (104) to the lumen of the inner shaft (106). In some variations, the tether may be maintained under tension outside the proximal handle, which may facilitate cutting the tether. The proximal handle (102) may include one or more actuating mechanisms (112) to control various components of the device, such as movement of the cutting blade (108) within the catheter lumen. For example, the actuating mechanism may be coupled to the cutting blade (108) and configured to move it from its first position in a first configuration to its second position in a second configuration. In some variations, a safety tab may be coupled to the actuation mechanism (112) to prevent the actuation mechanism from moving, and / or to prevent the cutting blade from moving, until the operator is ready to cut the tether. The safety tab helps protect the tether from being cut prematurely by keeping the cutting blade stationary in the lumen of the catheter until the tether is ready to be cut. Optionally, the proximal handle may include an additional actuation mechanism (112) configured to control the movement of the inner shaft (106) within the catheter lumen. The proximal handle (102) may also include various ports (107) to allow various devices and / or materials to leave and enter through the catheter. For example, the proximal handle may include a port through which the tether may pass to leave the catheter at the proximal end. The proximal handle may also include various flushing ports that allow the operator to introduce fluids such as saline solution into various components of the device. For example, the proximal handle may include ports for delivering fluids to the catheter lumen, the inner shaft, and / or the cutting blade. Any of the above ports may allow for the introduction of fluids (eg, saline, contrast media, drugs) and / or the introduction of devices (eg, implant delivery devices, catheters, imaging devices) into the lumen of any or all components of the catheter assembly.

[0018] Figure 1Bis a schematic depiction of an example of a tether passing through a tether cutting device. As shown, the tether cutting device may include a catheter (106) having a proximal end, a distal end, a catheter lumen (132) and an opening (151) in its side wall, an inner shaft (106), and a cutting blade (108) disposed on the inner shaft (106). The catheter lumen (132) may extend between a proximal end and a distal end. The inner shaft (106) may include a proximal end, a distal end, and an inner shaft lumen (144) extending between the proximal end and the distal end. The cutting blade (108) may include a proximal end, a distal end, and a cutting blade lumen (109) extending between the proximal end and the distal end. The cutting blade (108) may be slidably disposed around the inner shaft (106). The inner shaft (106) may be disposed in the cutting blade lumen (109), and the cutting blade (108) may be disposed in the catheter lumen (132) so that the catheter, the inner shaft, and the cutting blade are coaxially oriented. That is, the central longitudinal axes of each of the catheter, the inner shaft, and the cutting blade are substantially aligned with each other. In some variations, the catheter may include two or more side wall openings. The tether (118) may extend across a portion of the catheter lumen (132) between the side wall opening (151) and the inner shaft lumen (144). The tether (118) may extend through the entire length of the inner shaft lumen to the proximal handle ( Figure 1B ). The cutting blade may be capable of rotating and translating longitudinally on the inner shaft in order to contact and cut the tether.

[0019] The tether cutting device may include a first configuration and a second configuration. In the first configuration, the cutting blade may be retained in a position proximal to the distal end of the inner shaft. Figure 1B As depicted, the sharp portion (e.g., the distal-most end) of the cutting blade is located proximal to the distal end of the inner shaft (106). In this first configuration, the sharp portion of the cutting blade does not contact and / or cut the portion of the tether (118) extending between the inner shaft lumen (144) and the sidewall opening (151). This can help reduce the risk of inadvertently cutting the tether, for example, when the tether cutting device is advanced to a desired cutting position on the tether. In a second configuration, the cutting blade (108) may be located distal to the distal end of the inner shaft (106). When the cutting blade (108) is translated distally from a first position in the first configuration (i.e., a position proximal to the distal end of the inner shaft) to a second position in the second configuration (i.e., a position distal to the distal end of the inner shaft), it can contact and cut the tether (118). That is, when the cutting blade (108) moves distally, it can contact and cut the portion of the tether (118) extending between the sidewall opening (151) and the inner shaft lumen (144). In some variations, the cutting blade (108) may be simultaneously rotated and translated distally when the device transitions from the first configuration to the second configuration. Rotating and longitudinally translating the cutting blade may provide shearing forces that facilitate reliable and complete cutting of the tether.

[0020] although Figure 1B The variation of the tether cutting device depicted in has one sidewall opening in the catheter, but optionally, in some variations, the catheter may further include an opening at the distal end and a second sidewall opening. The second sidewall opening may be distal to the first sidewall opening. In some variations, the tether may pass into the catheter lumen through the distal opening, pass out of the catheter lumen through the second sidewall opening, and return to the catheter lumen through the first sidewall opening. As described above, the tether may then pass from the first sidewall opening and into the lumen of the inner shaft so that it passes through a portion of the catheter lumen. The tether may then extend proximally along the entire length of the inner shaft to the proximal handle of the tether cutting device and may exit the handle at the tether port.

[0021] Figure 2A and 2B An exemplary tether cutting device (200) is depicted. The tether cutting device (200) may include a proximal handle (202) attached to a catheter assembly (210) comprising a catheter, an inner shaft, and a cutting blade. The catheter includes an opening (214) at a distal end (216). An operator may pass a tether through the distal opening (214) at the distal end (216) of the catheter. The proximal handle (202) may include an actuating mechanism (212) for controlling movement of device components. For example, the actuating mechanism (212) may be used to control movement of the cutting blade within the lumen of the catheter. A safety tab (220) may be removably coupled to the actuating mechanism to prevent premature movement of one or more device components (such as a cutting blade). The proximal handle (202) may further include one or more ports to allow a device or substance to enter and exit the device. For example, a tether port (222) may allow a tether to exit the proximal handle. The proximal end of the tether extending through the port (222) may be held under tension by various mechanisms. For example, the proximal end of the tether may be attached to a weight. The proximal handle (202) may also include various flushing ports for introducing fluids into various components of the device. For example, the external flushing port (224) may be in fluid communication with the catheter, the internal flushing port (226) may be in fluid communication with the inner shaft, and the cutting blade flushing port (228) may be in fluid communication with the cutting blade.

[0022] In some variations, a proximal handle coupled to the catheter assembly can be configured to allow an operator to control the operation of the tether cutting device. Any suitable mechanism can be used to couple the catheter assembly to the proximal handle. For example, the catheter, inner shaft, and cutting blade can be held in place within the proximal handle by a friction fit. In another example, the immovable components (such as the catheter and / or inner shaft) can be soldered or molded to the proximal handle. In another example, the immovable components can be secured to the proximal handle using screws, brackets, or pins. The proximal handle can have a housing defining a substantially hollow internal body. Various components of the tether cutting device can be housed within the internal body of the proximal handle. The handle can have a proximal portion comprising one or more contours configured to allow an operator to easily grasp the handle. For example, the proximal portion of the housing can have one or more convex curves (e.g., Figure 2B The housing may further include one or more notches to provide comfortable placement of the fingers on the handle. The handle may be made of any suitable material. The proximal handle may also include various ports to accommodate the entry and exit of various devices and / or substances through the components of the tether cutting device. For example, the proximal handle may include a port through which the tether exits the handle (e.g., Figure 2A-2B The proximal handle may also include various flush ports that allow an operator to introduce liquids (such as saline solution) into various components of the device. For example, an external flush port may be in fluid communication with the catheter lumen to allow an operator to flush liquids through the catheter lumen. An internal flush port may be in fluid communication with the inner shaft to allow an operator to flush liquids through the inner shaft lumen. A cutter flush port may be in fluid communication with the lumen of the cutting blade to allow an operator to flush liquids through the cutting blade lumen. Various flush ports (e.g., Figure 2B The ports (224, 226, 228) depicted in the drawings can allow liquids such as saline solution, contrast media, drugs, or any suitable liquid to enter or leave the device. In addition, any of the above ports can also allow devices (such as implant delivery devices, catheters, imaging devices, or any suitable devices) to be introduced into the lumen of any component of the catheter system.

[0023] The housing of the proximal handle may include one or more openings to accommodate various components, such as buttons, turntables, wheels, ports and / or structures that can be used to control the operation of the device. For example, the housing may include an opening that is configured to accommodate an actuating mechanism so that the operator can control the actuating mechanism while gripping the proximal handle. A portion of the actuating mechanism may extend out of the opening in the housing, and another portion may be contained within the inner body. The actuating mechanism may be in the form of a rotatable wheel that may rotate to move the cutting blade. However, the actuating mechanism may include any suitable configuration, such as a rotatable sphere, a flat rectangular band or a rectangular or cylindrical recess. In addition, the actuating mechanism may include any suitable cross-section, including an oval, a triangle, a square or a rectangle. The actuating mechanism does not need to be moved by rotation, but may be moved in any suitable manner, including sliding, pulling or pushing. For example, the actuating mechanism may be in the form of a flat removable belt or a belt that is coupled to the cutting blade so that when the operator slides the belt, the inner shaft moves in a corresponding manner. Alternatively or additionally, the actuating mechanism may be in the form of a sliding notch coupled to the cutting blade so that when the operator slides the notch, the cutting blade moves in a corresponding manner. The actuating mechanism may also be in the form of a switch or button so that pushing the switch or button may be used to promote the movement of the cutting blade. The actuating mechanism may be used to promote the movement of the cutting blade in any suitable manner.

[0024] In one variation, the actuating mechanism can be coupled to the cutting blade within the inner body of the proximal handle. The actuating mechanism can be coupled to a lead screw, and the lead screw can be coupled to the cutting blade so that when the actuating mechanism rotates, the lead screw causes the cutting blade to move. The actuating mechanism can be coupled to the lead screw in any suitable manner, including the manner discussed below. The lead screw can be coupled to the cutting blade in any suitable manner. For example, the lead screw can be fixedly attached to the cutting blade such as by molding or soldering. The lead screw can facilitate the movement of the cutting blade in any suitable manner. For example, the threads on the outer surface of the lead screw can interact with the nut so that when the actuating mechanism rotates the lead screw, the threads of the lead screw interact with the inner surface of the nut, moving the positioning screw forward, thereby moving the cutting blade forward. As described below, various mechanisms can be used instead of the lead screw to facilitate the movement of the cutting blade.

[0025] Various mechanisms, such as gears, rack and pinion, slider crank mechanism, cam and roller, friction wheel, pulley or any other suitable mechanism can be used to actuate the cutting blade. These mechanisms can directly actuate the cutting blade, or they can engage with a lead screw or other similar device attached to the cutting blade to facilitate the movement of the cutting blade. Although the following example describes a cutting blade that interacts with various mechanisms to translate and / or rotate the cutting blade, a similar configuration is applicable to the modification in which the cutting blade is connected to the lead screw, and the lead screw can interact with any mechanism described below in a similar manner. For example, a gear can be used for translating and rotating the cutting blade. In a modification of the device described herein, the actuating mechanism can be connected to a gear, and the gear can be connected to a thread or notch surface on the cutting blade. Moving or rotating the actuating mechanism rotates the gear, and the gear engages with a thread or notch on the cutting blade surface to move it forward and / or rotate it. For example, the cutting blade can include a spiral thread extending around and along a portion of the proximal end. When the projection of the actuating mechanism engages the thread, the cutting blade can move forward and rotate. In another variation, the cutting blade may include a notch, a notch or a projection around the circumference. When the actuating mechanism engages the notch / notch / projection aligned circumferentially, the cutting blade may rotate around the axis. In another variation, the cutting blade may include a notch, a notch or a projection along the length of the cutting blade, so that when the projection of the actuating mechanism engages the notch / projection / notch of the cutting blade, the cutting blade moves forward. A rack and pinion mechanism may also be used for translating and / or rotating the cutting blade. For example, the actuating mechanism may be coupled to a gear or act as a gear so that when a user moves or turns the actuating mechanism, it engages a notch or a thread on the cutting blade, thereby converting the rotary motion of the actuating mechanism into a linear and / or rotary motion of the cutting blade. A slider crank mechanism may also be used for translating and / or rotating the cutting blade. For example, the actuating mechanism may be coupled to a rotating crank so that when the actuating mechanism moves, the crank rotates. The crank may be coupled to a rod, and the rod is coupled to the cutting blade so that the rotation of the crank causes the rod and the cutting blade to slide forward (or backward, depending on the direction of rotation). Cam and roller mechanisms can also be used to rotate and / or translate the cutting blade. For example, an actuating mechanism can act as or be coupled to a cam that rotates about an axis. When the cam rotates, it can engage and turn a roller that is coupled to the cutting blade to rotate and / or translate the cutting blade. A friction wheel can also be used to rotate and / or translate the cutting blade. For example, the actuating mechanism can be a friction wheel and can be coupled to a second friction wheel having a different orientation. The second friction wheel can be frictionally or otherwise coupled to the cutting blade so that rotation of the second friction wheel translates and / or rotates the cutting blade. A pulley system can also be used to rotate and / or translate the cutting blade. For example, the actuating mechanism can be coupled to one or more pulleys that are coupled to the cutting blade so that rotation of the actuating mechanism pulls a rope or string connecting the pulleys, and the pulleys translate and / or rotate the cutting blade.The electronic actuation mechanism may also be used to control the movement of various components of the device, including the cutting blade. For example, the actuation mechanism may act as an on / off switch for an electrical circuit. The electrical circuit may be electronically connected to the cutting blade such that the on / off switch causes the cutting blade to rotate and / or translate the blade.

[0026] As discussed above, the tether cutting device described herein may include one or more actuating mechanisms to control one or more aspects of the movement of the cutting blade. An actuating mechanism can control the rotation and translation (e.g., simultaneously) of the cutting blade. However, in another modification, the mobile actuating mechanism may only cause the rotation of the cutting blade. Similarly, the mobile actuating mechanism may only cause the cutting blade to move proximally or distally. Multiple actuating mechanisms may be used to control the movement of the cutting blade, each actuating mechanism being coupled to the cutting blade in any suitable manner so that the rotation and translation of the cutting blade are controlled by a separate actuating mechanism. In a modification, an actuating mechanism may be coupled to the blade so that the movement of the actuating mechanism is converted into linear motion, and a separate actuating mechanism may be coupled to the blade so that the movement of the actuating mechanism controls the rotational motion. For example, a first actuating mechanism may be coupled to a gear, and the gear may be coupled to a rod and a crank so that rotating the gear causes the linear motion of the blade. The second actuating mechanism can be connected to a gear, and the notch, breach or thread on the outer surface of the gear engagement lead screw or cutting blade is so that the cutting blade is rotated around the axis that the rotating gear causes the rotary motion of the blade. Any suitable mechanism can be used to control the rotation and translation motion of the cutting blade individually, including those mechanisms discussed above about controlling the simultaneous rotation and translation. In addition, the near side and distal movement of the cutting blade can be controlled by a separate mechanism. For example, the first actuating mechanism can be connected to a first one-way gear that only translates the blade distally. The second actuating mechanism can be connected to a second one-way gear that only translates the blade proximally. Any suitable mechanism can be used to control the near side and distal translation of the cutting blade individually, including those discussed above.

[0027] The proximal handle may also include a safety tab that is removably connected to the actuating mechanism. The safety tab may be used to keep the actuating mechanism stationary, thereby preventing movement of the device components. Various configurations of the safety tab are described below. In some variations, the safety tab is removably connected to the proximal handle, which is configured to hold the cutting blade in place. The safety tab may physically interfere with the actuating mechanism to prevent it from rotating, thereby preventing the cutting blade from moving. For example, the actuating mechanism may include a series of protrusions, and the safety tab may be inserted into the proximal handle between two protrusions of the actuating mechanism to prevent the actuating mechanism from moving.

[0028] Any suitable mechanism can be used to prevent the actuator from rotating. For example, the safety tab can include a small cylindrical or rectangular pin that fits into corresponding openings in the actuator and the proximal handle. Inserting the pin-shaped safety tab into the proximal handle and the actuator can prevent the actuator from rotating. In addition, any suitable mechanism can be used to keep the cutting blade in place in the catheter lumen until the operator is ready to move the blade to cut the tether. In some variations, the tether cutting device can use a stopper mechanism to prevent the lead screw from rotating, using a mechanism that prevents the lead screw from contacting the cutting blade, or using a mechanism that prevents the cutting blade from moving. In one variation, the stopper mechanism can be used to prevent the lead screw from rotating. For example, the safety tab can pass through the proximal handle and be inserted into the groove of the lead screw side wall so that the lead screw can no longer rotate. In another variation, the lead screw can be moved in the proximal handle so that the operator can control whether the lead screw contacts the cutting blade to control whether the cutting blade can move. For example, the lead screw can be held in a first position by the proximal handle, in which the lead screw does not contact the cutting blade, so that the cutting blade cannot move. The cutting blade can include a thread, or can be friction-fitted in the inner body of the proximal handle, so that it will not move unless the lead screw engages it. The lead screw can be held in place by the proximal handle by any suitable mechanism, including friction fit, thread, or a safety tab as described above about preventing the lead screw from moving. The operator can move the lead screw to a second position, in which the lead screw contacts the cutting blade to allow the cutting blade to move. The operator can move the lead screw from the first position to the second position in any suitable manner. For example, the operator can push or rotate the lead screw to a suitable position, or can remove the safety tab so that the moving lead screw contacts the cutting blade. In a further variation of the device described herein, a mechanism can be used to prevent the cutting blade from rotating. For example, as described above with respect to the lead screw, the cutting blade can include a groove in the side wall. The safety tab can be inserted through the proximal handle and inserted into the groove to prevent the cutting blade from rotating and / or translating. It should be understood that any suitable mechanism may be employed to interfere with the movement of the actuating mechanism, lead screw and / or cutting blade. In some variations, two or more mechanisms described herein may be combined to prevent movement of the cutting blade.

[0029] In one variation, the inner shaft is fixed within the lumen of the catheter. The inner shaft can remain stationary, for example, by coupling the inner shaft to the proximal handle of the tether cutting device using a friction fit of the inner body of the proximal handle. The inner shaft can also remain stationary by coupling the inner shaft to the housing of the proximal handle. The inner shaft can be coupled to any surface of the proximal handle using any suitable mechanism, including adhesives, soldering, brazing, bonding, fusion, hooks, screws, hinges, friction or interference fits, chucks, flared connections, or handles. Alternatively or additionally, the inner shaft may be able to move within the lumen of the catheter. For example, the inner shaft may be able to move distally and proximally within the lumen of the catheter.

[0030] The movement of the inner shaft can be promoted by an actuating mechanism. The actuating mechanism can be wheel-shaped so that the user promotes the movement of the inner shaft by turning the actuating mechanism. However, the actuating mechanism can include any suitable configuration, can have any suitable cross-section, and can be moved in any suitable manner, as described above with reference to the actuating mechanism, to control the cutting blade. The actuating mechanism does not need to be moved by rotation, but can be moved in any suitable manner, including sliding, pulling or pushing. For example, the actuating mechanism can be in the form of a flat movable belt or belt, so that the user slides the belt to move the inner shaft. Alternatively, the actuating mechanism can be in the form of a sliding recess so that the user slides the recess to promote the movement of the inner shaft. The actuating mechanism can also be in the form of a switch or button so that pushing the switch or button can be used to promote the movement of the inner shaft. The actuating mechanism that controls the movement of the inner shaft in the catheter lumen can be partially contained in the proximal handle of the tether cutting device. The inner shaft actuating mechanism can protrude through the opening in the inner shaft housing so that the operator can engage the actuating mechanism. The actuating mechanism can control the movement of the inner shaft in any suitable manner. For example, the actuation mechanism may be coupled to a lead screw, the rotation of which results in proximal or distal translation of the inner shaft. Any suitable mechanism (such as a gear, rack and screw, rack and pinion, slider crank mechanism, cam and roller, crank and rod, friction wheel, pulley, or any other suitable mechanism) may be used to actuate the inner shaft. As described above, when these mechanisms are used to facilitate movement of the inner shaft, the operation of these mechanisms relative to the movement of the cutting blade also applies to the operation of these mechanisms.

[0031] A variation of a tether cutting device with a movable inner shaft may also include a safety mechanism to hold the inner shaft stationary within the lumen of the catheter until the operator is ready to move the inner shaft. The mechanism may include an inner shaft safety tab coupled to the actuating mechanism, wherein the safety tab operates to physically interfere with the movement of the actuating mechanism, thereby preventing the movement of the inner shaft. For example, the actuating mechanism may include a series of protrusions, and the inner shaft safety tab may be inserted into the proximal handle and between two protrusions of the actuating mechanism to prevent the actuating mechanism from moving. However, any suitable mechanism may be used to prevent the movement of the actuating mechanism, including those described above with reference to the safety tab, to prevent the cutting blade actuating mechanism from rotating and / or translating the cutting blade.

[0032] In some variations of the tether cutting device described herein, the cutting blade can simultaneously rotate and translate about the inner axis to cut the tether. The simultaneous rotation and translation can allow the cutting blade to apply a shearing force or a cutting force on the tether so that the cutting blade can effectively cut through a sturdy surgical tether. However, in other variations of the tether cutting device, the cutting blade can not simultaneously rotate and translate. In one example, the device can include a blade that can only translate. In another example, the rotation and translation can be controlled by different mechanisms.

[0033] In some variations, the cutting blade can be translated both proximally and distally in the lumen of the catheter with similar or identical friction and tracking forces. That is, the operator can move the cutting blade both proximally and distally in the lumen of the catheter with substantially equal effort. The ability to easily advance and withdraw the cutting blade can allow for greater flexibility in manipulating the blade and can facilitate repositioning of the cutting blade. For example, the operator can advance the catheter, begin to actuate the blade, but then realize that the catheter should be repositioned. The bidirectional translation of the tether cutting device allows the operator to move the blade proximally in the lumen back to its more proximal position and reposition the catheter. In addition, the ability to translate the blade both proximally and distally gives the operator more than one opportunity to cut the tether in the event of a failure. For example, if the blade fails to successfully cut the tether, the operator can reposition the cutting blade and repeat the cutting process.

[0034] Figure 3A An exemplary variation of a tether cutting device (300) is shown, which includes a catheter (304), a cutting blade (308), and an inner shaft (306). The catheter includes a proximal end, a distal end (316), a lumen (332) extending between the proximal end and the distal end, and a distal opening (314). The distal portion of the catheter (304) can taper toward the distal opening (314). The cutting blade (336) includes a proximal end ( Figure 3A The inner shaft includes a proximal end (not shown), a distal end (336), and an inner lumen (338) extending between the proximal and distal ends. Figure 3A The inner shaft (306) and the cutting blade (308) are coaxially disposed within the catheter lumen (332). In this variation, the inner shaft (306) is disposed within the cutting blade lumen (338). This concentric arrangement is Figure 3C As further described in the figure, the figure is along Figure 3A Cross-sectional view taken along line 3C-3C. Figure 3C Depicted is an inner shaft (306) disposed within a cutting blade (308), and a cutting blade (308) disposed within a catheter (304). The cutting blade (308) may be movable around the inner shaft (306) within a lumen (332) of the catheter. Figure 3A The side wall (348) of the catheter includes a first opening (350) and a second opening (352). The second opening (352) is distal to the first opening (350). Figure 3A In the embodiment of the present invention, the first opening (350) and the second opening (352) are aligned circumferentially along the side wall (348) of the catheter, and the length of the catheter (354) is spaced therebetween. However, in some variations of the tether cutting device described herein, the first opening and the second opening may not be aligned circumferentially, but may be offset from each other so that each opening is located at a different circumferential position on the catheter. In addition, the length of the catheter (354) between the openings may be any suitable length. The tether (318) may pass into the lumen (332) of the catheter (304) through the distal opening (314), pass out of the lumen (332) of the catheter (304) through the second opening (352), and return to the lumen (332) of the catheter (304) through the first opening (350). The tether (318) can then extend from the first opening (350) into the lumen (344) of the inner shaft (306) such that the tether (318) extends across a portion of the catheter lumen (332) at an angle (α1) that is sufficiently shallow to facilitate low tracking forces when advancing the cutting device to or withdrawing it from a target site.

[0035] like Figure 3A As shown, the cutting blade (308) may have a first position in which the distal end (336) of the cutting blade (308) is proximal to the distal end (342) of the inner shaft (306). Figure 3A In the depicted first position, inner shaft (306) may protect tether (318) from being cut by cutting blade (308) by retaining the tether distal to the cutting blade. When cutting blade (308) is proximal to inner shaft (306), tether (318) cannot be cut by cutting blade (308). This arrangement may help protect tether (318) from being cut prematurely when cutting blade (318) is held in the first position.

[0036] Figure 3B A variation of the tether cutting device (300) is shown in which the cutting blade (308) has been changed from Figure 3A The first position described in the Figure 3B The second position is shown in Figure 3A , the distal end (336) of the cutting blade (308) is proximal to the distal end (342) of the inner shaft (306). Figure 3B In the embodiment of the present invention, the distal end (336) of the cutting blade (108) has been advanced through the distal end (342) of the inner shaft (306) to cut the tether, so that the distal end (336) of the cutting blade is distal to the distal end (342) of the inner shaft. The tether (318) forms a path traversed by the cutting blade (308) when the cutting blade (308) moves from the first position to the second position when extending between the first opening (350) and the inner cavity (344) of the inner shaft (306). In a variation of the device, the cutting blade (308) rotates and translates around the inner shaft simultaneously when it moves from the first position to the second position. The simultaneous rotation and translation can produce a shearing or cutting effect to effectively cut through the tether. The tether used in the surgical setting must be strong enough to hold the tissue mass together and can therefore be very difficult to cut. The cutting motion of the cutting blade (308) produced by the simultaneous rotation and translation can provide the benefit of allowing the cutting blade (308) to cut through very strong materials.

[0037] The devices and methods described herein may also provide the benefit of preventing the formation of loose pieces of tether after the tether has been cut. Figure 3A As depicted, the tether extends only across the portion of the catheter lumen (332) between the first opening (350) and the inner shaft (306). Thus, when the cutting blade (308) moves from the first position to the second position, the cutting blade (308) cuts the tether (318) at only one point along the length of the tether. This can provide the advantage of preventing the formation of loose pieces of tether. For example, if the tether extends completely across the lumen of the catheter, the cutting blade may contact the tether at more than one point. This may result in the formation of a piece of tether that is not attached to the target site or the proximal end of the tether. Loose pieces of tether are problematic because they may exit the catheter and enter the subject's body.

[0038] The devices and methods described herein may also provide the benefit of preventing the tether from falling out of the path of the cutting blade. Figure 3A and 3BIn the depicted arrangement, the tether can extend from the first opening (350) in the catheter and into the lumen (344) of the inner shaft. As the cutting blade (308) moves distally along the inner shaft (306) within the catheter lumen, it crosses the path of the tether (318) extending between the first opening (350) and the inner shaft lumen (344). In this arrangement, even if the tether (318) becomes slack, the cutting blade (308) will contact the tether (318) as the cutting blade (308) moves distally. Thus, Figure 3A and 3B The variation depicted in prevents the tether (318) from being able to escape the path of the cutting blade (308).

[0039] In some variations, the inner shaft can remain stationary within the lumen of the catheter. This can help simplify the operation and / or manufacture of the device, reduce operator error, and / or reduce the time required to operate the device. In addition, this can result in a lower risk of device failure associated with unintended movement of the inner shaft. In other variations, the inner shaft can be able to move within the lumen of the catheter. When the tether extends between the first opening of the catheter and the lumen of the inner shaft, the proximal and distal movement of the inner shaft can allow the operator to adjust the angle α1 of the tether (e.g., Figure 3A ). This ability to move the inner shaft can provide benefits such as allowing an operator to adjust the tracking force of the tether and / or facilitate cutting the tether. The inner shaft can have a predetermined range of motion within the catheter lumen, wherein the inner shaft can move proximally and distally within the range. The tether cutting device can have a retracted configuration in which the inner shaft moves proximally within the catheter lumen, and an extended configuration in which the inner shaft moves distally within the catheter lumen. When the inner shaft moves proximally into the retracted configuration, the angle between the tether and the inner shaft lumen (e.g., Figure 3A The angle α1 in the embodiment of the present invention can be reduced. The reduction in α1 can help reduce the amount of force (e.g., tracking force) used to advance the tether cutting device on the tether. The reduced tracking force can facilitate advancement of the catheter assembly on the tether. When the inner shaft moves distally into the extended configuration, the angle α1 increases. The increase in α1 can increase the portion of the tether that crosses the path of the cutting blade, which can facilitate cutting of the tether. Increasing α1 can also increase the tracking force, making it less likely that the tether cutting device will slip as the operator advances the cutting blade to contact and cut the tether.

[0040] Figure 4A An exemplary variation of the distal portion of a catheter (404) of a tether cutting device is depicted. Figure 4AAs depicted, the catheter (404) can be substantially cylindrical. However, in other variations, the catheter can be of any suitable shape. For example, the catheter can have a square, rectangular, oval, or triangular cross-section. The catheter can include an opening (414) located at the distal end (416). The opening can be configured to receive a tether. The catheter can have a distal tip portion (456) at the distal end (416). In some variations, the distal tip portion (456) can be tapered or have a generally conical profile. That is, in the tip portion, the circumference of the catheter narrows as it reaches the distal opening (414). The distal end (416) of the catheter (404) can have a non-damaged rounded edge (458). The rounded edge can prevent the catheter (404) from damaging the outer catheter through which the cutting catheter is advanced and / or injuring the patient when the catheter (404) is advanced to the target site. Furthermore, the rounded edges may prevent catheter ( 404 ) from partially or completely severing tether ( 418 ) in an undesirable location or at an undesirable time.

[0041] As described above, the conduit may include one or more openings in the conduit sidewall (448). For example, the conduit (404) may have a first opening (450) and a second opening (452), such as Figure 4A Depicted. The opening can be configured to receive a tether. The opening can be any suitable shape, such as oval, circular, rectangular, or square. The opening can also be any suitable size to allow the tether to pass through. The opening can also have rounded or smooth edges. The rounded or smooth edges can provide the benefit of preventing the opening from cutting or damaging the tether, such as, for example, during threading of the tether, and / or when the tether is tensioned, and / or when the catheter is advanced over the tether to a cutting position. The openings can be aligned with each other in any suitable manner. For example, the openings can be circumferentially aligned, such as Figure 4A However, the openings may have any suitable alignment. The spaces between the openings (454) may be any suitable distance. The spaces between the openings may include grooves or depressions (460), such as Figure 4AAs shown. The recess (460) can have a sufficient width to accommodate the tether. When the tether extends between the second opening (452) and the first opening (450), the recess (460) can provide the benefit of guiding the tether path. The recess (460) can have any suitable depth or width to accommodate the tether. An additional benefit of the recess (460) between the openings in the sidewall (448) of the catheter (404) is that when the cutting blade (408) is advanced to cut the tether, it can help keep the tether in place and under tension. For example, when the cutting blade contacts the tether, the recess can prevent the tether from moving laterally (for example, the rotation of the cutting blade can push the tether in a lateral direction, and the recess helps to help keep the tether stationary). Keeping the tether in place can facilitate the cutting of the tether. Alternatively or additionally, the catheter can include a tether lumen between the first and second openings, wherein the lumen can partially or completely enclose the tether extending between the first and second openings. In some variations, the lumen can be located within the thickness of the catheter sidewall. Alternatively, the conduit may not include a groove or recess between the first and second openings.

[0042] The catheter can be made of any suitable material, such as a polymer, plastic, metal, impregnated textile or cloth, natural or synthetic rubber, natural or synthetic fibers (including woven and / or braided fibers). The catheter can be flexible to facilitate easy movement of the catheter within the subject. The catheter need not have a consistent material in all parts of the catheter. For example, the catheter can be made of plastic at some locations and made of metal at other locations.

[0043] Figure 4B An inner shaft (406) is depicted positioned within a lumen (432) of a catheter (404). Figure 4B In the embodiment of the present invention, the distal end (442) of the inner shaft (406) is proximal to the first opening (450) in the catheter side wall (448). However, it should be understood that the distal end (442) of the inner shaft (406) can be located at any point within the catheter lumen (432). For example, the distal end (442) of the inner shaft (406) can be aligned with any point along the length of the first opening (450), or the distal end (436) of the inner shaft (406) can be distal to the first opening (450). For example, the distal end of the inner shaft (406) can be located between the first opening (450) and the second opening 452. In addition, the distal end (442) of the inner shaft (406) can be aligned with the second opening (452), or positioned distal to the second opening (452). Figure 4BThe inner shaft (406) is shown as having a circular cross-section, but it should be understood that the inner shaft (406) can be any suitable shape. For example, the inner shaft can have a square, rectangular, triangular or oval cross-section. In addition, the inner shaft (406) can be made of any suitable material. The inner shaft (406) can be flexible, or it can be rigid. In addition, as described above, the inner shaft (406) can remain stationary in the lumen (432) of the catheter (404), or it can be movable. For example, as described above, the inner shaft (406) can be able to move proximally and distally in the lumen (432) of the catheter. The distal end (442) of the inner shaft (406) can be blunt or rounded. The advantage of the inner shaft (406) with a blunt or rounded distal end is that it can prevent damage or accidental cutting of the tether. The rounded or blunt distal end (442) of the inner shaft (406) can protect the tether from being cut at an unexpected position or an unexpected time point.

[0044] As described above, the inner shaft (406) may include an inner cavity. The inner cavity of the inner shaft (406) may be configured to accommodate a tether. The inner shaft lumen may have any suitable diameter. For example, the diameter of the inner shaft lumen may closely follow the width of the tether, so that when the tether is contained in the inner shaft lumen (406), there is almost no extra space. However, the diameter of the inner shaft lumen may also be much larger than the width of the tether. The inner shaft (406) may be held in the lumen (432) of the catheter in any suitable manner. The inner shaft (406) may also be connected to the proximal handle in any suitable manner. For example, the inner shaft (406) may be molded to the surface of the proximal handle. In another variation, the inner shaft (406) may be held in place in the hollow inner body of the proximal handle by friction. For example, the inner shaft may be held in the inner body of the proximal handle by frictionally fitting the proximal portion of the inner shaft (406) contained in the inner body to the inner surface of the proximal handle.

[0045] Figure 4CA cutting blade (408) is depicted that is located within the lumen (432) of the catheter (404) and disposed on the inner shaft (406). As described above, the cutting blade (408) can be movably disposed around the inner shaft (406) in any suitable manner. For example, the cutting blade (408) can be capable of rotating and moving distally and proximally around the inner shaft (406) within the lumen (432) of the catheter (404). The distal end of the cutting blade (408) can have a sharp edge suitable for cutting a tether. The cutting blade can include a distal portion having a sharp edge and a proximal portion having a flexible shaft. The cutting blade (408) can be made of any suitable material. For example, the cutting blade can be made of stainless steel, metal, liquid crystal polymer, natural or synthetic gemstone or ceramic. In some variations, the cutting blade can be made of a heated material such as a nickel-chromium alloy and / or any conductive material and heated with electrical energy. A cutting blade comprised of any of the listed materials may also be combined with an energy output, such as radio frequency (RF), vibration energy, or laser-based energy, to facilitate cutting of the tether. The cutting blade may also be made of one or more materials. For example, the sharp edge of the cutting blade may be made of metal, while the body of the cutting blade may be made of plastic, and / or a braided or woven polymer and / or metal alloy. In some variations, the cutting blade may include a distal portion made of a rigid material, such as metal, and a proximal portion made of a flexible material, such as a flexible plastic or rubber. For example, in some variations, the cutting blade may include a sharp distal end made of metal and a flexible shaft made of flexible plastic. As Figure 4C As depicted, the cutting blade (408) has a circular cross-section, but the cutting blade may be any suitable shape. For example, the cutting blade may have an oval, square, rectangular, or triangular cross-section.

[0046] In the device described herein, the cutting blade can be moved to any suitable distance in the catheter lumen. For example, it is possible to move the cutting blade along the entire length of the catheter. However, it is also possible that the cutting blade may only be moved a certain distance in the catheter lumen. For example, the lead screw in the proximal handle that controls the movement of the cutting blade may only have enough threads to move the cutting blade a certain distance within the catheter length. It may also be the case that the lead screw engages with the threads on the cutting blade, and the cutting blade may only have enough threads to move a certain distance along the length of the catheter. In another variation, there may be a mechanism to prevent the cutting blade from moving past a certain point in the catheter lumen. Any suitable mechanism can be used to prevent the cutting blade from moving. For example, the cutting blade may include a notch on the outer surface, and the catheter may include a groove on the inner surface of the catheter side wall, which is configured to accommodate the notch or otherwise engage with the notch. The groove may be a complete opening in the catheter side wall, or it may be a groove or depression / recess in the catheter side wall. The notch on the cutting blade and the groove in the catheter can be arranged so that the notch cannot move out of the slot, but can slide along the slot. Therefore, the length of the groove can correspond to the distance that the cutting blade can move in the catheter lumen. In another variation, the catheter may include a notch, and the cutting blade may include a groove, which is used to limit the movement of the cutting blade as described above. In another variation, the catheter may include a protrusion on the inner surface of the side wall. The protrusion can extend into the lumen of the catheter so that when the distal end of the cutting blade contacts the protrusion, it can no longer advance in the lumen of the catheter. The protrusion can be at any suitable position along the length of the catheter, such as at or near the distal end. In another variation, the distal tip of the catheter can be tapered so that the cutting blade can no longer fit through the catheter lumen due to the reduction in the diameter of the catheter. Therefore, the cutting blade is prevented from moving beyond the point of the catheter lumen, at which point the diameter of the catheter is equal to or less than the diameter of the cutting blade. An advantage of providing a mechanism for stopping the cutting blade is that limiting the movement of the blade can prevent the blade from damaging the portion of the tether cutting device. For example, if the blade can move along the entire length of the catheter lumen, it may contact and damage the side wall of the catheter.

[0047] like Figure 5AAs shown, the tether cutting device may include a proximal handle (502). The proximal handle (502) may allow an operator to control the operation of the tether cutting device and control the movement of various components, such as the cutting blade and / or the inner shaft. The proximal handle (502) may include a housing (562) that defines a substantially hollow internal body. The housing (562) may include one or more openings to accommodate various components, such as buttons, dials, wheels, ports, and / or structures that can be used to control the operation of the device. For example, the housing (562) may include an opening (566) that is configured to accommodate an actuation mechanism (512) such that an operator can control the actuation mechanism (512) while grasping the proximal handle (502). Figure 5A In a variation of , the actuation mechanism (512) may include a rotatable disk (e.g., a wheel-shaped element or a turntable) having a series of protrusions (584) disposed around the outer circumference of the disk. Figure 5A The wheel-shaped actuation mechanism (512) depicted in the variation can be rotated by an operator to facilitate movement of the cutting blade. As described above, the actuation mechanism can include any suitable configuration, such as any suitable mechanism described herein.

[0048] The proximal handle may also house a safety tab (520) that is removably coupled to the actuation mechanism (512). Figure 5A A safety tab (520) inserted into an opening (568) in a proximal handle (502) is depicted. The safety tab opening (568) in the proximal handle (502) can allow the safety tab (520) to contact the actuating mechanism (512) to prevent the actuating mechanism (512) from moving until the safety tab (520) is removed. The proximal handle (502) can also include various ports to allow various objects to enter and exit through a catheter, an inner shaft, or a cutting blade. For example, the proximal handle (502) can include a tether port (570) located at the distal end to allow the tether to exit through the proximal handle. The tether port (570) that allows the tether to exit the proximal handle (502) can allow the tether to remain under tension outside the device. For example, one or more weights can be attached to the proximal portion (e.g., proximal end) of the tether that extends out of the tether port (570) to place the tether under tension. Various mechanisms can be used to keep the proximal portion of the tether under tension. For example, the operator may simply hold the tether while it is cut. The tether cutting device may also have a mechanism to hold the tether under tension, such as a hook, a handle, a pulley or any suitable mechanism to hold the tether under tension.

[0049] The proximal handle (502) may also include various flushing ports that allow the operator to introduce fluids into the various components of the device. For example, an external flushing port (572) may be in fluid communication with the catheter lumen to allow the operator to flush liquids through the catheter. An internal flushing port (574) may be in fluid communication with the inner shaft lumen to allow the operator to flush liquids through the inner shaft. A cutter flushing port (576) may be in fluid communication with the cutting blade lumen to allow the operator to flush liquids through the cutting blade. Various flushing ports may allow liquids to enter or leave the device. As described above, any port herein may also allow various devices and / or materials to enter and leave the tether cutting device.

[0050] Figure 5B and 5C is a side partial cross-sectional view of a tethered cutting device (500) illustrating examples of various mechanisms that may be used to control the movement of the cutting blade. Figure 5B As shown, an actuation mechanism (512) in a proximal handle (502) of a tether cutting device (500) can be coupled to a lead screw (578) housed within an inner body (564) of the proximal handle (502). The lead screw can be coupled to a cutting blade such that movement of the lead screw facilitates movement of the cutting blade. The lead screw can be coupled to the cutting blade in any suitable manner, such as by a friction fit of the cutting blade within an opening in the lead screw, fixedly attaching the proximal end of the cutting blade to the distal end of the lead screw (e.g., using an adhesive, soldering, or molding), or any other attachment mechanism. Figure 5B and 5C In a variation of the present invention, a lead screw (578) is coupled to the cutting blade (508) such that rotation of the lead screw is converted into rotation of the cutting blade (508) within the catheter lumen and proximal or distal (depending on the direction of screw rotation) movement (e.g., longitudinal translation).

[0051] exist Figure 5B and 5C In the embodiment of the present invention, when the user turns the actuator (512), the lead screw (578) rotates because the actuator is coupled to the lead screw via a friction fit of the lead screw (578) within the opening of the actuator (512). As described below, the opening of the actuator can be configured to conform to one or more surfaces of the lead screw to facilitate movement of the lead screw when the actuator is turned. The lead screw can interact with a nut in the proximal handle to facilitate longitudinal movement of the lead screw. For example, as Figure 5B and 5CAs shown, the lead screw (512) extends through the nut (579) such that when the actuation mechanism rotates the lead screw, threads on the lead screw engage with the inner surface of the nut to move the lead screw proximally or distally within the proximal handle (depending on the direction of rotation). The nut may include threads on the inner surface that engage with threads on the lead screw such that rotation of the lead screw causes the threads of the nut to engage with the threads of the lead screw to translate the lead screw distally or proximally. Thus, when the user rotates the actuation mechanism (512), the lead screw (578) moves from the proximal handle to the distal handle. Figure 5B The first position depicted is moved to Figure 5C The second position depicted. The nut and lead screw combination may facilitate longitudinal movement of the cutting blade in any suitable manner.

[0052] Figure 5D and 5E Exemplary variations of actuation mechanisms (512) and lead screws (578) coupled to actuation mechanisms (512) are shown. Figure 5D As depicted, the actuation mechanism includes a protrusion (584) and an opening (513), which can be configured to engage with a lead screw (578). That is, the opening (513) of the actuation mechanism (512) can be configured to match the dimensions of the outer surface of the lead screw (578). For example, Figure 5D The actuation mechanism depicted in FIG. 5 includes two flat surfaces (516) and two curved surfaces that are configured to mirror the surfaces of the lead screw. This may provide the benefit of improved engagement of the actuation mechanism (512) with the lead screw (578). However, the opening of the actuation mechanism may be configured in any suitable manner to have any combination of curved or flat surfaces. Figure 5E As shown, the lead screw (578) can extend through the opening (513) of the actuation mechanism (512). Figure 5E In the embodiment of the present invention, the actuator (512) is frictionally fitted to the lead screw (578) so that when the actuator rotates, it also rotates the lead screw. Figure 5E The lead screw (578) in includes two flat surfaces that are configured to mate with two flat surfaces of the actuating mechanism (512). However, the lead screw may include any suitable configuration suitable for fitting within an opening of the actuating mechanism. The actuating mechanism may be coupled to the lead screw in any suitable manner. For example, in some embodiments, the lead screw may not extend through an opening in the actuating mechanism. Instead, a protrusion on the actuating mechanism may interact with a thread or protrusion on the surface of the lead screw such that when the actuating mechanism rotates or moves, the protrusion on the actuating mechanism engages with the thread / protrusion on the lead screw. In another variation, the actuating mechanism may be in physical contact with the surface of the lead screw such that friction allows movement of the actuating mechanism to affect movement of the lead screw.

[0053] As described above, a mechanism (eg, a safety tab) may be used to hold the cutting blade in a stationary position within the catheter lumen until the operator is ready to cut the catheter. Fig. 5F and 5G Depicted are two views of a variation of a safety tab (520) that may be used to prevent the actuation mechanism (512) from rotating, thereby preventing the cutting blade from moving within the lumen of the catheter. Figure 5A , 5F In the arrangement shown in 5G, the safety tab (520) can be inserted into the opening (568) in the proximal handle and located between the two protrusions (584) of the actuating mechanism. When inserted between the two protrusions (584), the safety tab (520) physically interferes with the rotation of the actuating mechanism. In this arrangement, the operator can remove the safety tab (520) from the opening (568) in the proximal handle (502) to allow the cutting blade to move.

[0054] It should be understood that any suitable mechanism can be used to prevent the actuating mechanism from moving. For example, the safety tab can include a small cylindrical or rectangular pin that fits into the opening in the actuating mechanism and the proximal handle. Inserting the pin-shaped safety tab through the proximal handle and into the actuating mechanism can prevent the actuating mechanism from rotating. In addition, any suitable mechanism can be used to keep the cutting blade in the proper position in the catheter lumen until the operator is ready to move the blade to cut the tether. Alternatively or additionally, the tether cutting device can have a stopper mechanism that prevents the lead screw from rotating, a mechanism that prevents the lead screw from contacting the cutting blade, and / or a mechanism that prevents the cutting blade from moving. In a variation, the stopper mechanism can be used to prevent the rotational movement of the lead screw. For example, a safety tab or pin can pass through the proximal handle and be inserted into the groove in the side wall of the lead screw so that the tab / pin interferes with the rotation of the lead screw.

[0055] In another variation, the lead screw can be moved in the proximal handle so that the lead screw has a first position and a second position, in which the lead screw does not contact the cutting blade, and in the second position, the lead screw contacts the cutting blade. In the first position, the lead screw cannot move the cutting blade because the lead screw and the cutting blade do not contact. The cutting blade may include a thread, or may be friction-fitted in the inner body of the proximal handle so that it will not move unless it is engaged by the lead screw. The lead screw may be held in the first position by the proximal handle, which may be by any suitable mechanism, including a friction fit, a thread, or a safety tab that prevents the lead screw from moving as described above. In the second position, the cutting blade may move when the lead screw moves because the cutting blade contacts the lead screw. The operator may move the lead screw to contact the cutting blade in any suitable manner. For example, the operator may push or rotate the lead screw into position, or may remove the safety tab so that the moving lead screw contacts the cutting blade. In some variations, a mechanism may be used to prevent the cutting blade from rotating. For example, as described above about the lead screw, the cutting blade can include a slot in the side wall. A safety tab can be inserted through the proximal handle and inserted into the slot to prevent the cutting blade from rotating and / or translating. It should be understood that any suitable mechanism can be used to interfere with the movement of the actuating mechanism, the lead screw and / or the cutting blade. In addition, the mechanism for preventing the cutting blade from moving described herein can be used alone or in combination.

[0056] method Various methods of cutting the tether are also described herein. Figure 6600 may include advancing (602) a tether cutting device on a tether, applying tension (604) to the tether, and simultaneously rotating and translating (606) a cutting blade distally to cut the tether. Typically, an operator of the tether cutting device may advance a catheter assembly including a catheter, an inner shaft, and a cutting blade on the tether. In some variations, the operator may apply tension to the tether while advancing the catheter assembly on the tether (in addition to applying tension while rotating and translating the cutting blade to cut the tether). The tension may be applied to the tether in any suitable manner, such as the manner described below. The tether may be connected to a target site in a subject's body (e.g., as part of an implantable device). In some variations, advancing the catheter on the tether may include loading the tether into the tether cutting device. The operator may use a loading tool (e.g., a lasso) to facilitate loading the tether into the device. The loading tool may include a loop at one end through which the tether may be passed. Then, the tool can be pulled through the lumen of the catheter to pass the tether through the tether cutting device. Loading the tether can first include passing the tether into the catheter lumen through the distal opening of the catheter, and passing the catheter lumen through the second opening in the catheter side wall. Then, loading the tether through the device can include passing the tether back into the lumen of the catheter from the second opening in the catheter side wall through the first more proximal opening in the catheter. Loading the tether can then include passing the tether from the first opening, and passing the lumen of the inner shaft. This loading step can cause a portion of the tether to extend partially across the lumen of the catheter from the first opening in the catheter side wall to the lumen of the inner shaft. The tether can pass through the inner shaft, enter the proximal handle, and pass out from the proximal handle through the tether port.

[0057] After the tether is loaded into the device, the operator can apply tension to the tether. An advantage of the method of applying tension to the tether is that the tether under tension is easier to cut than a loose tether. The operator can apply tension to the tether in any suitable manner. For example, the operator can attach a weight to the proximal end of the tether to apply tension to the tether. In some variations, the operator can cover the portion of the tether located on the proximal side of the catheter assembly on the sterile rod. One or more weights can be clamped to the proximal end of the tether to apply tension. Any suitable weight can be used to apply tension to the tether. For example, a weighted hemostat (or other surgical tool) can be clamped to the tether. In another variation of the method described herein, the operator can simply keep the tether under tension. In another variation of the method described herein, the operator can pull the tether into a mechanism under tension and attach the tether to the tether cutting device, such as a hook, a groove, a notch or any other suitable mechanism, so that the tether is kept under tension. The operator may also utilize a mechanism of the tether cutting device designed to apply tension to the tether, such as a pulley, wheel, spool or hook, or any other suitable mechanism, to apply tension to the tether.

[0058] During operation of the device, the operator can advance the catheter along the tether at any suitable point. For example, the operator can complete all threading steps of loading the tether into the device, and then advance the catheter to the target site. In another variation, the operator can only complete a subset of the threading steps of loading the tether, and then partially advance the catheter along the tether to complete the loading of the tether into the device. For example, the operator can thread the tether into the catheter lumen through the distal opening, pass the tether out of the catheter lumen through the second opening in the catheter sidewall, and then partially advance the catheter along the tether before passing the tether through the rest of the tether cutting device. In a further variation, the operator can complete the loading of the tether, advance the tether cutting device to the target site, partially actuate the blade of the tether cutting device, and then further advance the tether cutting device along the tether. For example, the operator can start to actuate the blade and realize that the device has not been correctly positioned, prompting the operator to further advance the tether cutting device before completing the actuation of the cutting blade to cut the tether.

[0059] The operator can use the proximal handle to control the operation of the device. After the tether has been loaded into the tether cutting device, the operator can then use one or more actuators in the proximal handle to cut the tether. For example, the operator can move an actuator that controls the movement of the cutting blade to advance the blade within the catheter lumen and cut the tether. Figure 6In the variation shown, the operator can control the actuation mechanism that rotates and translates the cutting blade in the catheter lumen. In another variation, the operator can control a separate actuation mechanism to control the rotation and translation of the cutting blade. In order to use the actuation mechanism to move the cutting blade, the operator may need to deactivate a mechanism designed to keep the cutting blade stationary in the catheter lumen. For example, in order to move the cutting blade, the operator may need to remove the safety fin inserted into the proximal handle and connected to the actuation mechanism. In another variation, the operator can remove the safety fin connected to the cutting blade and / or the lead screw. In a further variation, the operator can only rotate or move the safety fin, rather than completely removing it from the proximal handle. After the operator has moved the cutting blade, the operator can replace the mechanism for keeping the blade stationary. For example, after the operator has cut the tether, the operator can use the safety fin to keep the blade in a stationary position in the catheter lumen while the device is extracted from the subject. In a variation, the cutting blade can be configured to move both distally and proximally in the lumen of the catheter. The operator can retract the cutting blade by moving the blade distally in the catheter lumen using an actuating mechanism. For example, the operator can move the cutting blade proximally by moving the actuating mechanism in one direction, and move the cutting blade distally by moving the actuating mechanism in the opposite direction. In another variation, the operator can actuate a separate actuating mechanism to move the cutting blade in the opposite direction. The advantage of the method in which the operator can move the cutting blade both distally and proximally is that the operator can move the cutting blade proximally to reposition the cutting blade in the catheter lumen.

[0060] Optionally, some variations may include translating the inner shaft to facilitate the cutting of the tether. For example, in a variation of the tether cutting device, in which the tether cutting device has a movable inner shaft, the operator can control the actuation mechanism to translate the inner shaft within the lumen of the catheter, for example, translating the inner shaft distally before actuating the cutting blade. For example, the inner shaft may have a predetermined range of movement, as well as a retracted position and an extended position within the range. The relative position of the inner shaft and the proximal sidewall opening of the catheter may affect the tracking force of the tether by changing the angle (e.g., angle α1) of the tether in the lumen of the catheter. The operator may adjust the angle of the tether by moving the inner shaft proximally or distally within the lumen of the catheter, and thus adjust the tracking force. For example, in order to reduce the tracking force, the operator may move the inner shaft proximally to a retracted position within the lumen of the catheter. The reduced tracking force may provide the benefit of making it easier for the operator to advance the catheter on the tether. Optionally, the operator may move the inner shaft distally to an extended position within the lumen of the catheter. Moving the tether distally within the catheter lumen can increase the portion of the tether in the path of travel of the cutting blade (i.e., so that a greater length of the tether is in contact with the blade), which can facilitate the cutting of the tether. In order to use the actuating mechanism to move the inner shaft, the operator can deactivate a mechanism designed to keep the inner shaft stationary within the catheter lumen. For example, the operator can remove a safety fin inserted into the proximal handle and connected to the actuating mechanism to move the inner shaft. In another variation, the operator can remove the safety fin connected to the cutting blade. In a further variation, the operator can only rotate or move the safety fin, rather than completely removing it. The operator may wish to maintain the position of the inner shaft within the catheter lumen at any point, such as after the operator has moved the inner shaft to the desired position. The operator can restart the safety mechanism to keep the inner shaft stationary, for example, by replacing the safety fin into the opening of the proximal handle of the tether cutting device. It should also be understood that in some variations of the tether cutting device, the operator will not move the inner shaft.

[0061] In some variations, the operator can check whether the tether has been successfully cut by the tether cutting device. For example, the operator can pull the proximal end of the tether and assess whether the tether has been cut. If the tether can be easily pulled, this may signal the operator that the tether has been completely cut. If there is still some tension in the tether, this may signal the operator that the tether has not been completely cut or not cut at all. If the tether is not completely cut (or not cut at all), the operator can retract the cutting blade, apply tension on the tether, and then advance the cutting blade distally again. Additionally, if it is suspected that the cutting blade and / or the inner shaft and / or any of its actuating mechanisms are damaged when the catheter is left in place, the operator can remove the cutting blade and / or the inner shaft and / or any of its actuating mechanisms, and replace the removed parts (e.g., cutting blade, inner shaft and / or actuating mechanism). For example, if a part of the device is damaged and should be replaced, this may be desired, but the operator prefers to keep the catheter in place when replacing the inner shaft and / or cutting blade. Because the tether can pass through the catheter, leaving the catheter in place when replacing other parts of the tether cutting device can provide such advantages, that is, by avoiding the need to pass the tether through the catheter again, the process of replacing parts is less troublesome. After the operator has confirmed that the tether has been successfully cut, the operator can retract the tether cutting device from the target site of the subject. The operator can use the proximal handle to pull the catheter assembly away from the target site and pull out the subject. Before retracting the device, the operator may wish to ensure that some elements of the catheter assembly (such as cutting blades and inner shaft) remain stationary in the catheter. As discussed above, when the device is retracted, the operator can utilize a mechanism such as a safety lug to keep the cutting blade and / or inner shaft in place.

[0062] Some variations of the methods described herein may include introducing a fluid or device into the lumen, inner shaft or cutting blade of a catheter. The proximal handle of the tether cutting device may include various ports to allow the operator to introduce a device and / or material into the tether cutting device. An outer port in communication with the catheter lumen fluid, an inner port in communication with the inner shaft lumen fluid, and a cutter port in communication with the cutting blade lumen fluid may allow the operator to introduce fluid into the catheter, inner shaft and cutting blade, respectively. For example, the operator may introduce a fluid such as saline solution, contrast agent, medicine or any suitable liquid into any component of the tether cutting device. The operator may also introduce one or more devices (such as an implant delivery device, a catheter, an imaging device or any other suitable device) into any component of the tether cutting device through various ports.

[0063] Although various inventive changes have been described and illustrated herein, various other means and / or structures may be used to perform functions and / or obtain results and / or one or more advantages described herein, and each such variation and / or modification is considered to be within the scope of the inventive changes described herein. More generally, all parameters, dimensions, materials, and configurations described herein are exemplary, and the actual parameters, dimensions, materials, and / or configurations will depend on the specific one or more applications taught by the present invention. There are many equivalents for the specific inventive changes described herein. Therefore, it should be understood that the aforementioned variations are given only as examples, and within the scope of the attached claims and their equivalents, the inventive variations may be practiced in a manner different from that specifically described and claimed. The inventive variations of the present disclosure are directed to each individual feature, system, article, material, kit, and / or method described herein. In addition, if two or more such features, systems, articles, materials, kits, and / or methods do not contradict each other, any combination of two or more such features, systems, articles, materials, kits, and / or methods is included within the scope of the invention disclosed herein.

[0064] In the claims, as well as in the above description, all transitional phrases, such as "comprises," "comprising," "carrying," "having," "containing," "involving," "maintaining," "consisting of," etc., are to be understood as open ended, i.e., meaning including, but not limited to. Only the transitional phrases "consisting of" and "consisting essentially of" are closed or semi-closed transitional phrases, respectively, as set forth in Section 2111.03 of the U.S. Patent Office Manual of Patent Examining Procedure.

Claims

1. A tether cutting device, comprising: a catheter comprising a proximal end, a distal end, a lumen therethrough, and a sidewall, wherein the sidewall comprises an opening; an inner shaft comprising a shaft lumen, wherein the inner shaft is disposed within the lumen of the catheter; A cutting blade disposed on the inner shaft; and An actuation mechanism is coupled to the cutting blade, the actuation mechanism being configured to rotate and translate the cutting blade about the inner shaft.

2. The device according to claim 1, wherein: The inner shaft is stationary within the lumen of the catheter.

3. The device according to claim 1, wherein: The inner shaft is movable within the lumen of the catheter.

4. The device of claim 3, further comprising a lead screw coupled to the inner shaft, wherein: Rotation of the lead screw translates the inner shaft.

5. The device of claim 4, further comprising an actuation mechanism coupled to the lead screw such that moving the actuation mechanism rotates the lead screw.

6. The device of claim 3, further comprising a gear mechanism coupled to the inner shaft, wherein: Rotation of the gear causes the inner shaft to translate.

7. The device of claim 1 further comprising a first configuration in which the distal end of the blade is proximal to the distal end of the inner shaft and a second configuration in which the distal end of the blade is distal to the distal end of the inner shaft.

8. The device according to claim 7, wherein: The actuation mechanism is configured to move the blade between the first and second configurations to cut the tether.

9. The device according to claim 1, wherein: The distal end of the inner shaft is blunt.

10. The device according to claim 1, wherein: The blade is tubular.

11. The device according to claim 1, wherein: The inner shaft is coaxial with the blade.

12. The device of claim 1 further comprising a proximal handle.

13. The device according to claim 12, wherein: The proximal handle includes the actuation mechanism.

14. The device according to claim 1, wherein: The actuation mechanism includes a lead screw coupled to the blade, wherein rotation of the screw rotates and longitudinally translates the blade.

15. The device according to claim 1, wherein: The actuation mechanism is configured to simultaneously slide the blade along the length of the catheter and rotate the blade about the longitudinal axis of the catheter.

16. The device according to claim 1, wherein The actuation mechanism is configured to bi-directionally move the blade distally and proximally within the catheter.

17. The device according to claim 1, wherein: The blade is retained within the lumen of the catheter by the actuation mechanism.

18. The device according to claim 1, wherein: The lumen of the catheter terminates at a distal opening.

19. The device according to claim 1, wherein: A tether extending from the opening and into the shaft lumen extends partially across the lumen of the catheter.

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