Articulation control device and method of use

Abstract

The medical device (10) includes a handle (20) including actuators (52, 54), a shaft (30) extending from the handle and having a longitudinal axis, a cam (70) rotatably coupled to the handle, the cam including a first section (84) and a second section (86), where a distance between a radially outer surface of the first section and a center of the cam is different from a distance between a radially outer surface of the second section and the center of the cam, and an actuation wire (100a, 100b) extending from the cam to a distal end of the shaft. Rotation of the actuator rotates the cam, causing the actuation wire to wrap around the first and second sections to deflect the distal end of the shaft.

Description

[Technical field]

[0001] The present disclosure relates generally to medical devices and related methods of use. More specifically, in some embodiments, the present disclosure relates to controlling the articulation of an endoscope and / or a medical instrument independent of or associated with an endoscope using one or more actuators. [Background technology]

[0002] A scope may be used to access a target site within the body, one or more medical tools may be advanced through one or more lumens of the scope, and the scope and / or medical tool may be articulated to gain access to, diagnose, or treat the target site. The handle may include one or more articulation mechanisms (e.g., knobs, etc.) that may be coupled to actuation wires. Actuation of the articulation mechanism by a user may cause articulation of a portion of the scope and / or medical tool. Drawbacks of these endoscopic systems include, for example, increased tension felt by the user when the articulation mechanism is rotated to maximize flexion of the articulation member. For example, as the articulation mechanism is rotated, the actuation wires coupled to the articulation member wrap around the articulation mechanism and / or a member (e.g., a cam) attached to the articulation mechanism, increasing the tension felt by the user. This increased tension may cause hand fatigue, which may create difficulties in performing treatment. Additionally, conventional articulation mechanism designs may change the articulation response of the scope and / or medical tool as the articulation mechanism is rotated. This can decrease the responsiveness of the articulation joint as the angle of the articulation joint relative to the longitudinal axis of the scope increases. The present disclosure may solve one or more of these or other problems in the art. However, the scope of the disclosure is defined by the appended claims, rather than the ability to solve any particular problem. Summary of the Invention

[0003] According to one aspect, a medical device includes a handle including an actuator, a shaft extending from the handle and having a longitudinal axis, a cam rotatably coupled to the handle, the cam including a first section and a second section, where a distance between a radially outer surface of the first section and a center of the cam is different from a distance between a radially outer surface of the second section and the center of the cam, and an actuator wire extending from the cam to a distal end of the shaft, where rotation of the actuator rotates the cam and causes the actuator wire to wrap around the first section and the second section to deflect the distal end of the shaft.

[0004] The first section and the second section may define a travel path for the actuation wire, and the first section may have a first radius of curvature and the second section may have a second radius of curvature.

[0005] The radially outer surface of the first section may define a first curve having a first radius of curvature, which may be uniform from a first end of the first curve to a second end of the first curve, and the radially outer surface of the second section may define a second curve having a second radius of curvature, which may decrease in magnitude from the first end of the second curve to the second end of the second curve.

[0006] The cam may include a third section extending from the second section, and the first section, second section, and third section may form a continuous path.

[0007] The third section may include a linear radially outer surface, and the distance between the center of the cam and the linear radially outer surface may vary along the entirety of the third section. A distance between the radially outer surface of the second section and a centre of the cam may be greater than a distance between at least a portion of the radially outer surface of the third section and the centre of the cam.

[0008] The fourth section may extend from the third section, and a distance between a radially outer surface of the fourth section and a center of the cam may be equal to a distance between a radially outer surface of the first section and a center of the cam.

[0009] The first section and the second section may form a first path, and the second path may be formed on the cam in a plane parallel to the plane of the first path, and the second path may include a first portion having a first radius and a second portion having a second radius, and the first radius and the second radius may be unequal.

[0010] The first path and the second path may be parallel to the first path and the second path between the first path and the second path and may not be mirror images about a plane that bisects the cam. Rotation of the cam in a clockwise direction may cause the actuation wire to be wound onto a first path, and rotation of the cam in a counterclockwise direction may cause the second actuation wire to be wound onto a second path.

[0011] Rotation of the actuator through an angle between 0 and 180 degrees may be configured to deflect a portion of the shaft at a smaller angle relative to the longitudinal axis of the shaft than rotation of the actuator between 180 and 360 degrees.

[0012] The cam may include a recess, and a diameter of a proximal portion of the actuation wire may be larger than a diameter of a distal end of the actuation wire, and the proximal portion of the actuation wire may be configured to be received by the recess.

[0013] The actuator may be keyed to the cam and movement of the actuator may be configured to move the cam. The locking mechanism may be rotatable about the same axis as the cam, and the locking mechanism may be configured to move from a first position to a second position, and the cam may be rotatable when the locking mechanism is in the first position and the cam may not be rotatable when the locking mechanism is in the second position.

[0014] The apparatus may further include a second actuator and a second cam keyed to the second actuator, the second cam may include a path having a first radius and a second radius, and the first radius and the second radius may be different.

[0015] According to another aspect, a medical device may include a handle including an actuator, a shaft extending from the handle and having a longitudinal axis, and a cam rotatably coupled to the handle, the cam including a first section and a second section defining a path of travel for an actuator wire, a radially outer surface of the first section having a first radius of curvature and a radially outer surface of the second section having a second radius of curvature different from the first radius of curvature, and actuation of the actuator causes the actuator wire to wrap around the radially outer surfaces of the first and second sections to bend the shaft.

[0016] The pathway may further include a third section extending from the second section, and the first section, second section, and third section may form a continuous pathway.

[0017] The cam may further include a second path parallel to the first path, and the first path and second path may be rotationally offset about a central axis of the cam. According to another aspect, a method includes inserting a shaft of an insertion device into a body through an opening; advancing the insertion device so that a distal end of the insertion device is adjacent a target site; rotating a first control mechanism in a first direction about a rotation axis; and deflecting the shaft from a position parallel to a longitudinal axis of the shaft based on the rotation, wherein a torque on the first control mechanism is gradually decreased as the first control mechanism rotates in the first direction.

[0018] Continued rotation of the first control mechanism in the first direction may cause an increasing torque on the first control mechanism. [Brief description of the drawings]

[0019] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate various exemplary embodiments and, together with the description, serve to explain the principles of the disclosed embodiments. [Figure 1] 1 is a schematic diagram of a medical system according to one embodiment. [Diagram 2] FIG. 2 is a schematic diagram of a handle of the endoscopic system of FIG. 1 in accordance with one embodiment. [Diagram 3] 2 is a schematic end view of a cam member of the endoscopic system of FIG. 1 in accordance with one embodiment. [Figure 4] FIG. 4 is a side view of the cam member of FIG. 3 according to one embodiment. [Diagram 5] 5 is a cross-sectional view of the cam member taken along line 5-5 of FIG. 4 according to one embodiment. [Figure 6] 6 is a cross-sectional view of the cam member taken along line 6-6 of FIG. 4 according to one embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] The present disclosure is described with reference to exemplary medical systems and medical tools for accessing a target site, for example, from different directions and / or different angles at the distal end of an endoscope. This may provide improved medical tool functionality and / or assist a medical professional in gaining improved access to a target site to perform a medical procedure. However, it should be noted that reference to any particular device and / or any particular procedure is provided for convenience only and is not intended to limit the present disclosure. Those skilled in the art will recognize that the concepts underlying the disclosed devices and application methods may be utilized in any suitable device or procedure, medical or otherwise. The present disclosure can be understood with reference to the following description and the accompanying drawings, in which like elements are referred to with the same reference numerals.

[0021] For ease of description, portions of the disclosed devices and / or their components are referred to as proximal and distal portions. It should be noted that the term "proximal" is intended to refer to the portion of the device closer to the user, and the term "distal" is used herein to refer to the portion further from the user. Similarly, extending "distally" indicates that the component extends in a distal direction, and extending "proximally" indicates that the component extends in a proximal direction. Furthermore, as used herein, the terms "about," "approximately," and "substantially" indicate a range of values ​​within + / - 10% of the stated or implied value. Furthermore, terms indicating the geometry of components / surfaces refer to exact and approximate shapes.

[0022] Referring to FIG. 1, a medical system 10 is shown according to one embodiment. The medical system 10 may include a handle 20, a shaft 30 (e.g., catheter, sheath, etc.) extending from a distal end of the handle 20, and a distal tip 40 at the distal end of the shaft 30. The handle 20 may include a number of ports 60, 62, 64 that may be fluidly connected to one or more lumens (not shown) that extend from a proximal end of the shaft 30 and may terminate at one or more openings (not shown) in the distal tip 40. A medical tool may be introduced through the one or more ports 60, 62, 64 and exposed from the openings (not shown) in the shaft 30 and / or distal tip 40 to perform one or more treatments on the target tissue. Alternatively or additionally, suction and / or fluid sources may be attached to one or more ports 60, 62, 64 to remove tissue or other matter by suction and / or introduce fluids to the target site. Alternatively or additionally, one or more of the ports 60, 62, 64 may be attached to a display or control device via an umbilicus (not shown). The umbilicus may include one or more wires that may connect to wires of an imaging device and / or illumination device (not shown) provided at the distal tip 40. Control signals and / or power may be provided to the imaging device or illumination device to control their operation.

[0023] The handle 20 may further include actuators 52, 54 (e.g., knobs) that may be pivotally coupled to the handle 20 by an axis A. A locking mechanism 56 may also be rotatably coupled to the handle 20 along the axis A and may rotate about the axis A from a first position to a second position. In the first position, the locking mechanism 56 may prevent rotation of the actuators 52, 54. When the locking mechanism 56 is in the second position, the actuators 52, 54 may be free to rotate about the axis A. It will be understood that more than one locking mechanism 56 may be coupled to the handle 20 such that each of the actuators 52, 54 includes a locking mechanism 56. The locking mechanism 56 may be any known locking mechanism for preventing rotation of the actuators (e.g., the actuators 52, 54 shown in FIG. 2) and may include a rotatable lever, a twisting device, or the like.

[0024] With reference to FIG. 2, the actuators 52, 54 are aligned along axis A. A cam 70 may be keyed to each of the actuators 52, 54, i.e., each actuator 52, 54 is coupled to a corresponding cam 70 (a single cam 70 is shown in FIG. 2 for ease of understanding). The cam 70 may be disposed within the housing 20a of the handle 20. As described herein, the first and second actuation wires 100a, 100b may be attached to the cam 70. The first and second actuation wires 100a, 100b may extend distally through the handle 20 into the shaft 30 and may be coupled at their distal ends to one or more locations, e.g., an articulation joint, of the shaft 30 and / or the distal tip 40. As described in more detail herein, rotation of one of the actuators 52, 54 about axis A, e.g., in a clockwise or counterclockwise direction, may rotate the cam 70 in the same direction. As the cam 70 is rotated, slack in either the first actuation wire 100a (e.g., when the cam 70 is rotated in a clockwise direction) or the second actuation wire 100b (e.g., when the cam 70 is rotated in a counterclockwise direction) may take up and begin to wrap around the cam 70, which may cause the distal tip 40 and / or a portion of the shaft 30 to bend relative to the longitudinal axis B.

[0025] According to one example, each actuator 52, 54 may be coupled to the cam 70 via a shaft. For example, a first shaft (not shown) may connect the actuator 52 to the first cam 70, and a second shaft (not shown) may connect the actuator 54 to the second cam 70. As described herein, the cam 70 and the actuator 52, 54 may share a common axis of rotation. In some examples, one or both of the first and second shafts may include a lumen such that one of the first or second shafts may be disposed within the lumen of the respective shaft. In other words, the first shaft may surround the second shaft, or the second shaft may surround the first shaft. In this manner, the first and second shafts may be coaxial. This allows the actuators 52, 54 and the respective cams 70 to be coaxial as well.

[0026] The cam 70 may include a first side 70a and a second side 70b, as shown in FIGS. 3 and 4. The first actuation wire 100a (FIG. 2) may include a ferrule (not shown) at its proximal-most end. The ferrule may have a diameter larger than the diameter of the distal portion of the first actuation wire 100a. The ferrule may be seated within a slot 80 (e.g., a recess or opening) (FIG. 5) formed in the outer surface of the first side 70a. Seating the ferrule within the slot 80 may secure the first actuation wire 100a relative to the cam 70. A portion of the first actuation wire 100a may be received by a recess 82 (FIG. 5) to allow the first actuation wire 100a to extend from the slot 80 into the recess 82 and wrap around all or a portion of the circumference of the cam 70. The second side 70b of the cam 70 may have a similar configuration. For example, a slot 80' may be formed in the outer surface of the second side 70b of the cam 70, and a ferrule (not shown) of the second actuation wire 100b may be received in the slot 80'. The ferrule may have a diameter larger than the diameter of the distal portion of the second actuation wire 100b. A portion of the second actuation wire 100b may be received by a recess 82' (FIG. 6) to allow the second actuation wire 100b to extend from the slot 80' and wrap around all or a portion of the circumference of the cam 70 in a direction opposite to that of the first actuation wire 100a.

[0027] 3 and 4, the first wire path 76 may be formed closer to a first side 70a of the cam 70, and the second wire path 78 may be formed closer to a second side 70b of the cam 70. For example, wall 72a may define an outermost surface of the cam 70 on the first side 70a, wall 72b may define an outermost surface of the cam 70 on the second side 70b, and wall 72c may be formed between the first wire path 76 and the second wire path 78. According to one example, the first wire path 76 may be a circumferential slot and may be formed between or defined by walls 72a and 72c, each of which may extend radially further than the outermost surface of the first wire path 76. The second wire path 78 may also be a circumferential slot and may be formed between walls 72b and 72c or may be defined by walls 72b and 72c, each of which extends radially further than the outermost surface of the second wire path 78.

[0028] A cross section of the first side 70a along line 5-5 of FIG. 4 is shown in FIG. 5. The first wire path 76 may include one or more sections, such as a first section 84, a second section 86, a third section 88, and a fourth section 90. The first section 84 may include a curved radially outermost surface extending from the recess 82 to the second section 86. The second section 86 may include a curved radially outermost surface extending from the first section 84 to the third section 88. The third surface 88 may include a straight radially outermost surface extending from the second section 86 and terminating at an end opposite the second section 86. The fourth section 90 may include a curved radially outermost surface extending from the third section 88 and terminating at the recess 82. In other embodiments, each of the first section 84, second section 86, third section 88, and fourth section 90 may include curved and / or straight portions. The first wire path 76 may include less than four sections, such as, for example, one, two, three, five, six, or more sections, or may include more than four sections, and the shapes of the sections may be curved and / or straight. It will be understood that the first section 84, second section 86, third section 88, and fourth section 90 may form a single continuous path along the first wire path 76. Alternatively, openings or cuts along the first wire path 76 may be formed to reduce material without impairing the ability of the actuation wire to wind on and off the first path 76 as described herein. It will also be appreciated that any of sections 84, 86, 88, or 90 may be formed from a plurality of linear sections, which may form a generally circular surface.

[0029] As will be described in more detail, the distance from the center C of the cam 70 to each point along the radially outermost surface of each of the first section 84, the second section 86, the third section 88, and the fourth section 90 may be constant or may vary. For example, the distance between the center C of the cam 70 and a point on one or more of the first section 84, the second section 86, the third section 88, and / or the fourth section 90 may vary over one or more portions of each section. For example, as shown in FIG. 5, the distance between the surface of the second section 86 and the center C may decrease from the first section 84 to the third section 88.

[0030] According to one example, the first section 84 may extend from the recess 82 approximately 50 percent around the circumference of the cam 70. The distance between the center C and a point along the radially outermost surface of the first section 84 may be constant along the entirety of the first section 84. This constant distance may increase the torque felt by a user when an actuation mechanism coupled to the cam 70 rotates to wind an actuation wire (e.g., actuation wire 100a) onto the first section 84. This constant distance may provide increased control of the articulation joint as compared to when the actuation wire is wound onto the second section 86 and the third section 88. For example, as described herein, a small amount of rotation of the cam 70 as the articulation wires wind on and off the first section 84 may provide improved steering control of the articulation joint than the same amount of rotation of the cam 70 as the articulation wires wind on and off the second section 86 or the third section 88. In some examples, the distance between a point along the radially outermost surface of the first section 84 and the center C of the cam 70 may be greater than conventional cam devices, which may improve steering control of the actuation joint at low rotation angles. The distance between the surface of each of sections 84, 86, 88, and 90 and the center C may be about 0.100 inches to about 0.500 inches. The angular distance of the first section 84 (e.g., the circumferential distance around the cam 70) can be from about 90° to about 150°, the angular distance of the second section 86 can be from about 70° to about 130°, the angular distance of the third section 88 can be from about 10° to about 70°, and the angular distance of the fourth section 90 can be from about 50° to about 110°.

[0031] 5, the second section 86 may be curved. The distance between a point along the radially outermost surface of the second section 86 and the center C of the cam 70 may decrease from the end of the first section 84 toward the beginning of the third section 88. This decreasing distance may reduce the amount of tension a user feels when the user rotates the corresponding actuator 52, 54. As discussed above, the responsiveness of the articulation joint may also decrease based on this decreasing distance.

[0032] The third section 88 may include a linear radially outermost surface such that the distance between the third section 88 and the center C may decrease from the intersection of the second section 86 and the third section 88 toward the center of the third section 88, and then increase from the center of the third section 88 toward the end of the third section 88. This decreased distance relative to the distance between the center C and the first section 84 may reduce the amount of tension felt by the user when the cam 70 and associated actuation mechanism are rotated about axis A in FIG. 2. The fourth section 90 may include a curved radially outermost surface. In some examples, the distance from all points along the fourth section 90 may be the same distance from the center C of the cam 70 as a point along the first section 84. In some embodiments, the rotation of the cam 70 may be terminated such that the actuation wire does not wrap around the fourth section 90. In other embodiments, the actuation wire is wrapped around the fourth section 90. As discussed above, the responsiveness of the articulation joint when the actuation wire is disposed along the third section 88 may be reduced relative to the responsiveness of the articulation joint when the actuation wire is wound on and off the first section 84. For example, the first section 82 may extend approximately half (e.g., 180 degrees) of the circumference of the cam 70. In this case, rotation of the cam 70 from 0 degrees to 180 degrees may deflect the shaft 30 at a smaller angle relative to the longitudinal axis A than when the cam 70 is rotated between 180 degrees and 360 degrees.

[0033] A cross section of the second side 70b along line 6-6 of FIG. 4 is shown in FIG. 6. The second wire path 78 of the second side 70b may include sections similar to the first wire path 76, such as a first section 84' that may include a curve with a constant radius, a second section 86' that may include a curve with a decreasing radius, a third section 88' that may be a straight line, and a fourth section 90' that may include a curve with a radius that is the same as or different from the radius of the curve of the first section 84'. However, it will be understood that the first section 84', second section 86', third section 88', and fourth section 90' are not limited to these orientations and may include one, two, three, five, six, or more sections, similar to the first wire path 76. Also, the distance between the section of the first wire path 76 and the center C of the cam 70 and the distance between the section of the second wire path 78 and the center C of the cam 70 may be the same or different. The first wire path 76 and the second wire path 78 may include the same number of sections, as shown in Figures 5 and 6, or may have a different number of sections. It will be understood that the first section 84', the second section 86', the third section 88', and the fourth section 90' may form a single continuous path along the second wire path 78. Alternatively, openings or cuts along the second wire path 78 may be formed to reduce material without impairing the ability of the actuation wire to wind on and off the first path 76, as described herein. It will also be understood that any of the sections 84', 86', 88', or 90' may be formed from multiple straight sections, which may form a generally circular surface.

[0034] As shown in FIG. 4, the first side 70a and the second side 70b of the cam 70 may be parallel to each other or may be inverted with respect to each other. In other words, the first wire path 76 and the second wire path 78 may not be mirror images with respect to a plane between the first wire path 76 and the second wire path 78 and parallel to the first wire path 76 and the second wire path 78. The first wire path 76 and the second wire path 78 may be offset by about 20 degrees as shown in FIG. 4. In this case, the cam 70 can control the right / left deflection of the shaft 30 and / or the distal tip 40. The offset of the first wire path 76 and the second wire path 78 may allow the actuation wire coupled to one wire path, e.g., the first wire path 76, to be in a relaxed state while the actuation wire coupled to the other wire path, e.g., the second wire path 78, is in a tensioned state. The offset of the first wire path 76 and the second wire path 78 may allow for machining of the cam 70 and / or may prevent the actuation wire from migrating from one path to another during use. In another example, the first wire path 76 and the second wire path 78 are not radially offset from one another. According to one example, the first wire path 76 may extend in a first direction, e.g., a clockwise direction, around the cam 70, while the second wire path 78 may extend in an opposite direction, e.g., a counterclockwise direction, around the cam 70. Rotation of the cam 70 in a first direction (e.g., a clockwise direction) may cause the first actuation wire to be wound onto the first wire path 76 and / or the second actuation wire to be unwound from the second wire path 78. Rotation of the cam 70 in a second direction opposite to the first direction (e.g., a counterclockwise direction) may cause the first actuation wire to be unwound from the first wire path 76 and / or the second actuation wire to be wound onto the second wire path 78.

[0035] A method of operation of the medical system 10 may be described. The medical system 10 may be inserted into the body through an opening (e.g., an incision) or through a natural orifice. The distal tip 40 may be advanced to a target site by pushing the shaft 30 distally. As the shaft 30 is pushed distally, the medical system 10 may follow one or more serpentine paths. A user may rotate the actuator 52 in a clockwise or counterclockwise direction, which may deflect the distal tip 40 in a first plane, e.g., up and down relative to the longitudinal axis B, and the actuator 54 may be rotated in a clockwise or counterclockwise direction, which may deflect the distal tip 40 in a second plane, e.g., left and right relative to the longitudinal axis B. As the actuators 52, 54 are rotated, the articulation mechanism (e.g., wires) may be wound by the corresponding cam 70 in the direction in which the actuators 52, 54 are turned. For example, by rotating an actuator keyed or coupled to cam 70, actuation wire 100a begins to unwind and wrap around first section 84. The user may have improved control over the articulation of shaft 30 and / or distal tip 40 at this stage, although the torque felt by the user may increase as articulation wire 100a continues to wrap onto first section 84.

[0036] Continued rotation of the actuator 52 may cause the actuation wire 100a to wrap around the second section 86. As the actuation wire 100a wraps around the second section 86, the control over the actuation of the shaft 30 and / or the distal tip 40 may decrease, but the torque felt by the user may also decrease. Continued rotation of the actuator 52 may cause the actuation wire 100a to wrap around the third section 88. As the actuation wire 100a wraps around the third section 88, the control over the actuation of the shaft 30 and / or the distal tip 40 may increase, but the torque felt by the user may also increase. It will be appreciated that the actuator 52 and / or actuator 54 may be rotated multiple times both clockwise and / or counterclockwise during a procedure. Thus, the torque felt by the user and the control over the shaft 30 and / or the distal tip 40 may continue to change during rotation based on the position of the actuation wire on the respective cam 70.

[0037] Although the embodiment has been described in connection with an actuation mechanism attached to the handle 20 for deflecting the shaft 30 and / or distal tip 40, it will be understood that any medical device used in conjunction with or separate from the medical system 10 may include the cam 70 described herein, and the cam 70 may be used to deflect a portion of the medical device or to reduce torque associated with rotation of the actuation device.

[0038] It will be apparent to those skilled in the art that various modifications and variations can be made to the disclosed device without departing from the scope of the present disclosure. For example, variations in the torque felt by the user, changes in the control of the shaft and / or distal end, and the number of actuation mechanisms may be modified based on the desired medical treatment. Other embodiments of the present disclosure will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. It is intended that the specification and examples be considered as exemplary only, with the true scope and spirit of the invention being indicated by the following claims.

Claims

1. a handle including an actuator; a shaft extending from the handle and having a longitudinal axis; a cam rotatably coupled to the handle, the cam including a first section and a second section, the distance between a radially outer surface of the first section and a center of the cam being different from the distance between a radially outer surface of the second section and the center of the cam; an actuation wire extending from the cam to a distal end of the shaft, wherein rotation of the actuator rotates the cam and causes the actuation wire to wrap around the first section and the second section to deflect the distal end of the shaft.

2. 2. The device of claim 1, wherein the first section and the second section define a path of travel for the actuation wire, the first section having a first radius of curvature and the second section having a second radius of curvature.

3. 3. The apparatus of claim 2, wherein the radially outer surface of the first section defines a first curve having the first radius of curvature, the first radius of curvature being uniform from a first end of the first curve to a second end of the first curve, and the radially outer surface of the second section defines a second curve having the second radius of curvature, a magnitude of the second radius of curvature decreasing from the first end of the second curve toward the second end of the second curve.

4. The apparatus of claim 1 , wherein the cam includes a third section extending from the second section, the first section, the second section, and the third section forming a continuous path.

5. 5. The apparatus of claim 4, wherein the third section includes a linear radially outer surface, and the distance between the center of the cam and the linear radially outer surface varies along an entirety of the third section.

6. 6. The apparatus of claim 5, wherein a distance between the radially outer surface of the second section and the center of the cam is greater than a distance between at least a portion of the radially outer surface of the third section and the center of the cam.

7. 5. The apparatus of claim 4, further comprising a fourth section extending from the third section, wherein a distance between a radially outer surface of the fourth section and the center of the cam is equal to a distance between the radially outer surface of the first section and the center of the cam.

8. 2. The apparatus of claim 1, wherein the first section and the second section form a first path and a second path is formed on the cam in a plane parallel to the plane of the first path, the second path including a first portion having a first radius and a second portion having a second radius, the first radius and the second radius being unequal.

9. 9. The apparatus of claim 8, wherein the first path and the second path are parallel to the first path and the second path between the first path and the second path and are not mirror images about a plane that bisects the cam.

10. 9. The device of claim 8, wherein clockwise rotation of the cam causes the actuation wire to wrap onto the first path and counterclockwise rotation of the cam causes a second actuation wire to wrap onto the second path.

11. 2. The device of claim 1, wherein rotation of the actuator through an angle between 0 and 180 degrees is configured to deflect a portion of the shaft at a smaller angle relative to the longitudinal axis of the shaft than rotation of the actuator from 180 to 360 degrees.

12. The device of claim 1 , wherein the cam includes a recess, a diameter of a proximal portion of the actuation wire is larger than a diameter of a distal end of the actuation wire, the proximal portion of the actuation wire being configured to be received by the recess.

13. The apparatus of claim 1 , wherein the actuator is keyed to the cam such that movement of the actuator moves the cam.

14. 2. The apparatus of claim 1, further comprising a locking mechanism rotatable about the same axis as the cam, the locking mechanism configured to move from a first position to a second position, the cam being capable of rotating when the locking mechanism is in the first position and the cam being unable to rotate when the locking mechanism is in the second position.

15. A second actuator; and and a second cam keyed to the second actuator, the second cam including a path having a first radius and a second radius, the first radius and the second radius being different.

Images