Linear rotation mechanism for hemostasis clip device and other devices

A medical device includes a handle, a flexible member extending from a proximal end connected to the handle to a distal end, a rotation mechanism connected to the distal end of the flexible member, an end effector coupled to a distal portion of the rotation mechanism and a push member extending through the handle and flexible member and connecting to the rotation mechanism, the rotation mechanism being configured and dimensioned to convert axial movement of the push member into rotation of the end effector.

BACKGROUND

Pathologies of the gastro-intestinal (“GI”) system, the biliary tree, the vascular system and other body lumens are commonly treated through endoscopic procedures, some of which require active and/or prophylactic hemostasis to control internal bleeding. Specialized endoscopic devices are used to deliver the hemostasis devices (e.g., clips) to desired locations within the body and to position and deploy the hemostasis devices at the desired locations. Manipulation of the hemostasis device about a portion of target tissue is often difficult and may require extensive effort including attempts to rotate the hemostasis device relative to the target tissue to achieve proper positioning of the clip to ensure adequate sealing of a wound or other opening in tissue. However, when such a long flexible device is rotated, they tend to wind-up making it difficult or impossible to effectively transmit rotation to the hemostasis devices in a controlled manner.

SUMMARY OF THE INVENTION

The present invention is directed to a medical device comprising a handle, a flexible member extending from a proximal end connected to the handle to a distal end, a rotation mechanism connected to the distal end of the flexible member, an end effector coupled to a distal portion of the rotation mechanism and a push tube extending through the handle and flexible member and connecting to the rotation mechanism, the rotation mechanism being configured and dimensioned to convert axial movement of the push tube into rotation of the end effector.

DETAILED DESCRIPTION

The present invention may be further understood with reference to the following description and the appended drawings, wherein like elements are referred to with the same reference numerals. The present invention relates to a device enabling rotation of an end effector attached to a flexible endoscopic device. In one embodiment of the invention, the end effector is a device for applying one or more hemostatic clips. The exemplary device according to the invention permits rotation of the clip(s) to aid in positioning thereof relative to target tissue. Specifically, the exemplary device according to the invention is configured to rotate the clip(s) relative to an outer sheath encasing the clip(s). The rotation mechanism converts an axial force applied at a proximal actuator into a rotational force rotating the clip(s). It is noted that although the rotation mechanism disclosed herein has been described with respect to clipping devices, the rotation mechanism may also be designed to perform any of a variety of endoscopic procedures including, but not limited to, band ligation, injection therapy, thermal electrohemostasis, fine-needle aspiration, etc. and the end effector may comprises any opening/closing instrument selected from the group comprises a clip, combination therapy needle, biopsy forceps, scissors, graspers, clamps, etc. It should be noted that the terms “proximal” and “distal,” as used herein, are intended to refer to a direct toward (proximal) and away from (distal) a user of the device.

As shown inFIGS. 1-4, a device100according to an exemplary embodiment of the invention extends along a longitudinal axis103from a proximal end (not shown) including a handle102accessible to a physician or other user in an operative configuration to a distal end (not shown) comprising an end effector (not shown). In an operative configuration, the end effector (not shown) is inserted into a living body (e.g., through a naturally occurring bodily orifice, a percutaneous orifice, transluminal access, or the like) and advanced through the body (e.g., via a natural body lumen, a percutaneous orifice, transluminal access, or the like) to a site adjacent to target tissue. As indicated above, the end effector (not shown) according to this embodiment comprises a clip containing capsule101a proximal end of which is releasably attached to a bushing104which is coupled to a rotation mechanism, as will be described in greater detail later on. The rotation mechanism is further connected to a distal end of a flexible member106which is coupled to the handle102. The flexible member106according to this embodiment is formed as an elongated coil with a channel108extending therethrough and is sized and configured for insertion through a working channel of an endoscope (i.e., with an outer diameter less than an inner diameter of the working channel).

The handle102includes an elongated channel110extending therethrough divided into first110a, second110band third110csections open to one another. The first section110aextends from the proximal end109of the handle102distally a predetermined distance. The first section110ahas an outer diameter substantially equivalent to or greater than an outer diameter of a push tube112extending through the handle102. Specifically, the push tube112extends longitudinally through the handle102to the channel108and extends distally therepast a predetermined distance to a torque gear122, as will be described in greater detail below. A control wire111extends through the push tube112and distally therefrom to connect to an end effector (not shown). In an exemplary embodiment, the push tube112may be formed of one or more of Nitinol, PEEK, and any plastic material having similar mechanical properties including sufficient rigidity and flexibility. The second section110bextends distally from a distal end of the first channel section110aa predetermined distance and has an outer diameter greater than an outer diameter of the first section110a. In an exemplary embodiment, the outer diameter of the second section110bis substantially equivalent to or greater than an outer diameter of a push tube grip114permanently attached to an outer wall of the push tube112. The push tube grip114is formed as a substantially cylindrical element immovably gripping an outer wall of the push tube112. As those skilled in the art will understand, the push tube grip114may be attached to the push tube112by a weld, crimp, adhesive or other attachment mechanism. The push tube grip114is configured to be both rotatable and longitudinally movable within the second section110b. The push tube grip114maintains longitudinal alignment with the central longitudinal axis103by engagement with walls of the second section110b. In an exemplary embodiment, the second section110bis dimensioned so that the push tube grip114may move axially therewithin by approximately 19.05 mm, although any other length is also envisioned without deviating from the scope of the invention. The third section110cextends distally from a distal end of the second section110bto the distal end of the handle102. An outer diameter of the third section110cis configured and dimensioned to receive a portion of the flexible member106therein. The third section110calso comprises a flared crimp band116having a plurality of flared protrusions118configured to frictionally engage walls of the third channel section110c. In an operative configuration, the crimp band116is crimped onto the flexible member106to permanently affix the flexible member106to the handle102. It is noted, however that any other attachment mechanism may be used without deviating from the scope of the invention (e.g., welding, adhesive, etc.).

The flexible member106extends distally from the handle102by a length conforming to the requirements of a particular procedure. A distal end of the flexible member106is coupled to a rotational base120formed, for example, of Delrin or any other material with similar mechanical properties to provide a lubricious surface aiding in rotation of an end effector (not shown) coupled thereto. In one exemplary embodiment, the rotational base120may be coated with Teflon, silicone, graphite, melted polymer, or any other suitable biocompatible material having similar properties, as those skilled in the art will understand. The push tube112extends through the rotational base120and terminates at a torque gear122distal of the rotational base120. Specifically, a distal end of the push tube112in this embodiment is connected to the torque gear122via one or more of a weld, screw thread, cross pin, crimp and an adhesive although any other attachment means may be used without deviating from the scope of the invention. As shown inFIGS. 2-3, the torque gear122is housed within a substantially cylindrical and hollow torque converter126. A proximal end128of the torque converter comprises four slots130cut therein (e.g., laser-cut, stamped, etc.) and extending through a wall thereof. The proximal end128is positioned over a recessed groove132provided on a distal end of the rotational base120and crimped to form four crimp bands134with the crimp bands134configured to axially hold the rotational base120against the torque converter126while permitting rotation of the rotational base120relative thereto. It is noted that any number of sufficient crimp bands134is conceivable, including two, three, five, six, and so forth without deviating from the scope of the invention. The crimp bands134also permit pivotal deflection of the torque converter126relative to the rotational base120by approximately 10° relative to the central longitudinal axis103. It is noted, however, that the torque converter126may deflect relative to the rotational base at approximately 5-20° without deviating from the scope of the invention. In yet another embodiment, the torque converter126may deflect by approximately 0-20° or 0-30° to, for example, permit accommodation of an end effector (not shown) that does not pivot relative to a longitudinal axis. As those skilled in the art will understand, this deflection enhances flexibility of the device100aiding in insertion thereof to a target site in a body. As those skilled in the art will understand, an angularity of the torque converter may be influenced by one or both of a depth of the groove132and a height of the crimp bands134. Furthermore, the crimp bands134may have optimized cross-sectional profiles (e.g., triangular, arched, etc.) to influence the angularity. In an alternate embodiment (not shown), the groove123may instead be formed as one or more protrusions including a rib extending around a perimeter of the distal end of the rotational base120. In this embodiment, the crimp bands134may be formed as one or more grooves configured to receive the protrusions or rib and crimped thereover.

The torque gear122is formed as an elongated substantially cylindrical element having a first proximal cylindrical portion136with a first outer diameter. In an exemplary embodiment, the first outer diameter is smaller than an inner diameter of the rotation base120through which the torque gear122extends. The torque gear122also comprises a second cylindrical portion138having an outer diameter substantially equal to or less than the inner diameter of the torque converter126and larger than the inner diameter of the rotation base120. The second cylindrical portion138comprises first and second wings140extending radially outward from opposing walls thereof. The wings140according to this embodiment have a substantially rectangular cross-section and are configured to engage slots142machined into the torque converter126and extending along a length thereof. However, wings140may be optimized for movement within slots142, for example by having a substantially round profile. Furthermore, a contour area of each of the wings140may be minimized to reduce friction with the slots142. In one embodiment, the edges of the wings140may be substantially rounded. The torque converter126comprises a pair of elongated slots142extending proximally from a distal end thereof in a substantially helical pattern. In an exemplary embodiment, the slots142extend through the torque converter126. In another embodiment (not shown), the slots142may extend into a wall of the torque converter126by a limited depth configured to engage the wings. In yet another embodiment, only one slot142may be provided. Although the exemplary embodiment depicted inFIGS. 1-3is described with two helical slots142and two wings140, any number of wings and slots may be used without deviating from the scope of the invention. Furthermore, a length and curvature of the slots142may be modified to impart a desired rotation to an end effector, as will be described in greater detail below. Specifically, the slots142should be arranged over the torque converter126to minimize an amount of force required to convert axial translation into rotation, as those skilled in the art will understand.

In an operative configuration, axial movement of the push tube112and the torque gear122is translated to rotation of the end effector (not shown) due to engagement of the wings140with the slots142. Specifically, since the torque gear122is unable to rotate independently of the flexible member106, axial movement of the push tube112in a distal direction causes the torque converter126and any components attached to a distal end thereof, to rotate. In one embodiment, a distal end144of the torque converter126is permanently attached to the bushing104via a weld, crimp, or other fixation method, as those skilled in the art will understand. The bushing104may be further connected to a capsule101housing a clip or other end effector which, consequently, rotates therewith. The exemplary device according to the invention permits rotation of the torque converter126and end effector independently of the flexible member106and handle102, thus avoiding complications due to winding-up along the length of the flexible member. Specifically, as shown inFIG. 4, the rotational base120comprises a guide rib121located on an inner wall thereof and configured to mate with a guide groove123provided on an outer wall of the torque gear122. This mating arrangement compels alignment between the torque gear122and the rotational base120attached to the flexible member106facilitating engagement of the wings140with the slots142to permit a conversion of axial movement of the push tube112into rotation.

In accordance with an exemplary method of the invention, an end effector is attached to the capsule101and the flexible member106is inserted through an endoscope until a distal end of the device100comprising the end effector (not shown) extends from the distal end of the endoscope exposed to a target portion of tissue. The device according to the invention is configured to prevent unwanted axial movement of the push tube112when the push tube112has been moved to a desired position. Specifically, the push tube112is configured such that a neutral axis thereof is maintained along its central longitudinal axis regardless of a curvature thereof. In contrast, the flexible member106, which is formed of a coil, is configured such that its neutral axis deviates from a central longitudinal axis thereof when curved during insertion, permitting the flexible member106to adjust a length thereof to aid in insertion through tortuous anatomy. This configuration allows a length of the flexible member106to adjust during insertion through the body while preventing unwanted movement of the push tube112. In another embodiment (not shown), the handle102may comprise a locking mechanism (not shown) configured to lock an axial position of the push tube112relative to the flexible member106. The locking mechanism may be formed as a ratchet pinion, gears, ratchet, etc.

In some embodiments, the end effector (not shown) or any part of the device100may have an endoscopically visible marker (e.g., radiopaque, etc.) to provide visual feedback of an orientation thereof within the body. Once the end effector (not shown) has been positioned at a target location, a physician or other user moves the push tube112distally via an actuation mechanism (not shown) on the handle102. In an exemplary embodiment, distal movement of the push tube grip114by approximately 6.35 mm within the second section110bis sufficient to rotate the end effector (not shown) a complete cycle as dictated by the wings140and slots142. As those skilled in the art will understand, a remaining length of the second section110bis provided to permit axial movement of the push tube grip114therewithin when the device100is inserted through tortuous anatomy. Specifically, as noted above, an overall length of the flexible member106is changed when bent to permit insertion through tortuous anatomy. Since the push tube112and push tube grip114maintain a constant effective length, movement of the push tube grip114within the second section110benhances flexibility of the flexible member106. Once the end effector has been rotated to a desired orientation relative to the target tissue, the control wire111extending through the device100is actuated to move the end effector to perform a desired operation (e.g., clip tissue, etc.) Specifically, the control wire111may operably move the end effector (e.g., a clip) between a closed configuration wherein first and second arms are separated from one another by a first distance and an open configuration wherein the first and second arms are separated from one another by a second distance greater than the first distance. In addition, the whole device100may still be rotated to provide further rotation to the end effector separately from the rotation provided by the torque converter126.

It will be understood by those of skill in the art that individual features of the embodiments described above may be omitted and or combined to form alternate embodiments. Furthermore, it will be understood by those skilled in the art that various modifications can be made in the structure and the methodology of the present invention, without departing from the spirit or scope of the invention. For example, although the present invention has been described with respect to a clipping device, the exemplary system and method may also be used to perform biopsy procedures or any other medical procedure wherein improved rotation of a component is required in combination with a function of opening/closing a device, extending/retracting a device into tissue, etc., as those skilled in the art will understand. Furthermore, although the present invention has been described with respect to a removable capsule101, the exemplary rotation drive mechanism according to the invention may also be used with a biopsy tool or any other medical device non-removably attached to the rotation drive mechanism. Furthermore, the torque converter126may be formed as a part of an end-effector in an embodiment wherein the end-effector is permanently attached to the device100. It is therefore respectfully submitted that the exemplary rotation drive mechanism according to the invention may be employed in any other medical device requiring precise rotational control without deviating from the spirit and scope of the invention. Thus, it is intended that the present invention cover the modifications and variations of this invention provided that they come within the scope of the appended claims and their equivalents.