Abstract:
An elongate access sheath comprises a proximal portion and a lumen. The proximal portion supports a control handle, a brake pad, a tension gear, and a locking trigger. A deflector filament extends through the lumen and is coupled to the tension gear. The tension gear includes an outside and an inner engagement portion. The brake pad comprises a slot and an outside engagement portion. The locking trigger includes a pin disposed within the brake pad slot. The control handle includes a lever and an engagement portion. Upward movement of the lever engages the engagement portion with the outside engagement portion of the tension gear to rotate the tension gear in a first direction and slides the deflector filament to bend the lumen distal portion. Translation of the locking trigger engages the brake pad and the tension gear to prevent rotation of the tension gear in an opposite second direction.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority from U.S. provisional application No. 61/895,566, filed on Oct. 25, 2013, the entirety of which is hereby fully incorporated by reference herein. 
    
    
     TECHNICAL FIELD 
     This disclosure relates to devices for the manipulation and guidance of medical tools within the body, in particular medical devices with a deflectable distal end. 
     BRIEF SUMMARY 
     An elongate access sheath comprises a distal portion, a proximal portion, and a lumen. The proximal portion supports a control handle, a brake pad, a tension gear, and a locking trigger. A deflector filament extends through the lumen and is coupled to the tension gear. The tension gear is rotatably mounted to the proximal portion and includes an outside engagement portion and an inner engagement portion. The brake pad is disposed within the hollow center of the tension gear and comprises a slot and an outside engagement portion. The locking trigger is attached to the tension gear and includes a pin that is disposed within the slot of the brake pad. The control handle includes a lever and an engagement portion. Upward movement of the lever causes the engagement portion to mesh with the outside engagement portion of the tension gear to rotate the tension gear in a first direction and slides the deflector filament within the lumen to bend the distal end. Translation of the locking trigger engages the brake pad and the tension gear to prevent rotation of the tension gear in an opposite second direction. 
     In one embodiment, an elongate access sheath comprises a distal portion, a proximal portion, and an elongate portion extending therebetween, the elongate portion defines a lumen therethrough, and the distal portion is bendable with respect to a longitudinal axis of the elongate portion. The proximal portion supports a control handle, a brake pad, and a tension gear. The deflector filament slidably extends through the lumen and is operatively coupled to the distal portion and the tension gear, wherein the at least one deflector filament is mounted so that rotation of the tension gear urges sliding movement within the lumen. The tension gear is rotatably mounted to the proximal portion and includes an outside engagement portion, wherein the outside engagement portion has teeth that are located on an outside engagement portion of the tension gear. The control handle comprises a lever portion and an engagement portion that comprises input teeth. The input teeth of the engagement portion are meshed with the outside engagement portion of the tension gear such that upward movement of the lever portion causes rotation of the tension gear in a first direction and sliding motion of the deflector filament within the lumen urges the distal portion to bend with respect to the longitudinal axis. 
     In another embodiment, an elongate access sheath comprises a distal portion, a proximal portion, and an elongate portion extending therebetween, the elongate portion defines a lumen therethrough, and the distal portion is bendable with respect to a longitudinal axis of the elongate portion. The proximal portion supports a control handle, a brake pad, a tension gear, and a locking trigger. The deflector filament slidably extends through the lumen and is operatively coupled to the distal portion and the tension gear, wherein the at least one deflector filament is mounted so that rotation of said tension gear urges sliding movement within said lumen. The tension gear is rotatably mounted to the proximal portion and includes an outside engagement portion and an inner engagement portion, wherein the outside engagement portion comprises teeth that are located on an outside engagement portion of the tension gear, and the inner engagement portion comprises teeth that are located upon a surface of a hollow center of said tension gear. The brake pad is disposed within said hollow center of said tension gear and comprises a slot and an outside engagement portion, wherein said opening is disposed vertically on said brake pad and an outside engagement portion is located on the outside engagement portion of the brake pad and aligned to engage the inner engagement portion of the tension gear. The locking trigger is attached to the tension gear and includes a body portion and a pin, wherein the pin is disposed within the slot of the brake pad. The control handle comprises a lever portion and an engagement portion that comprises input teeth, wherein the input teeth of the engagement portion are meshed with the outside engagement portion of said tension gear such that upward movement of the lever portion causes rotation of the tension gear in a first direction and sliding motion of the deflector filament within the lumen to urge the distal portion to bend with respect to the longitudinal axis, wherein translation of the locking trigger causes the pin to slide within the slot and urge engagement between the brake pad and the tension gear thereby preventing rotation of the tension gear in an opposite second direction, wherein the outside engagement portion prevents the rotation of the tension gear in an opposite second direction. 
     In another embodiment, an elongate access sheath provides for an engagement between said brake pad and said tension gear to form a ratchet. The ratchet is formed from the outside engagement portion of the brake pad that is comprised of angled teeth and the outside engagement portion of the tension gear that is comprised of angled teeth, wherein the angled teeth are angled in an opposite second direction to restrict movement of the tension gear when the brake pad and the tension gear are engaged. The ratchet formed allows further rotation of the tension gear in a first direction upon additional upward movement of the lever portion while preventing rotation of the tension gear in an opposite second direction. 
     In another embodiment, an elongate access sheath comprises a distal portion, a proximal portion, and an elongate portion extending therebetween, the elongate portion defines a lumen therethrough, and the distal portion is bendable with respect to a longitudinal axis of the elongate portion. The proximal portion supports a control handle, a brake pad, a tension gear, and a locking trigger. The deflector filament slidably extends through the lumen and is operatively coupled to the distal portion and the tension gear, wherein the at least one deflector filament is mounted such that rotation of said tension gear urges sliding movement within the lumen. The tension gear is rotatably mounted to the proximal portion and includes an outside engagement portion and an inner engagement portion, wherein the outside engagement portion comprises teeth that are located on an outside engagement portion of the tension gear. The brake pad is disposed within the hollow center of the tension gear and comprises a slot and a friction portion, wherein the opening is disposed vertically on the brake pad and the friction portion is located on the outside engagement portion of the brake pad and aligned to engage the inner engagement portion of the tension gear. The locking trigger is attached to the tension gear and includes a body portion and a pin, wherein the pin is disposed within the slot of said brake pad. The control handle comprises a lever portion and an engagement portion that comprises input teeth, wherein the input teeth of the engagement portion are meshed with the outside engagement portion of the tension gear such that upward movement of the lever portion causes rotation of the tension gear in a first direction and sliding motion of the deflector filament within the lumen to urge the distal portion to bend with respect to the longitudinal axis, wherein translation of the locking trigger causes the pin to slide within the slot and urge engagement between the brake pad and the tension gear thereby preventing rotation of the tension gear in an opposite second direction. 
     In another embodiment, a method of deflecting the distal end of a lumen of an elongate access sheath which includes a control handle, a tension gear, and a deflector filament attached proximally to the tension gear and distally to the lumen. The method includes the steps of actuating the control handle in an upward direction, wherein the actuating causes the control handle to engaged the tension gear and to cause rotation of the tension gear in a first direction. Further, sliding the filament in a proximal direction to urge the distal end to bend with respect to the longitudinal axis. 
     In another embodiment, a method of deflecting the distal end of a lumen of an elongate access sheath that further includes a brake pad and a locking trigger. The method further includes the steps of translating the locking trigger to bring the brake pad in contact with the locking trigger. Further, the locking trigger is prevented from moving in a second direction which prevents the deflector filament from returning to a configuration along the longitudinal axis. 
     Other systems, methods, features and advantages of the invention will be, or will become, apparent to one with skill in the art upon examination of the following figures and detailed description. It is intended that all such additional systems, methods, features and advantages be within the scope of the invention, and be encompassed by the following claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings are included to provide a further understanding of the claims, are incorporated in, and constitute a part of this specification. The detailed description and illustrated examples described serve to explain the principles defined by the claims. 
         FIG. 1 a    is a perspective view of an embodiment of the deflectable access sheath. 
         FIG. 1   b  is a cross-sectional side view of the deflecting mechanism of the deflectable access sheath of  FIG. 1   a.    
         FIG. 2 a    is a cross-sectional view of the deflecting mechanism of the deflectable access sheath of  FIGS. 1 a   - 1   b.    
         FIG. 2 b    is a cross-sectional view of the deflecting mechanism of the deflectable access sheath of  FIG. 2 a    where the locking trigger is shown transparent to better see the connections of the gear locking system. 
         FIG. 3  is a cross-sectional side view of the sheath housing of a deflectable access sheath. 
         FIG. 4 a    illustrates a side view of the tension gear of the deflecting mechanism in  FIGS. 2 a   - b.    
         FIG. 4 b    illustrates a perspective view of the tension gear of the deflecting mechanism in  FIGS. 2 a   - b.    
         FIG. 5 a    illustrates a side view of the brake pad of the deflecting mechanism in  FIGS. 2 a   - b.    
         FIG. 5 b    illustrates a perspective view of the brake pad of the deflecting mechanism in  FIGS. 2 a   - b.    
         FIG. 6 a    illustrates a side view of the control handle of the deflecting mechanism in  FIGS. 2 a   - b.    
         FIG. 6 b    illustrates a perspective view of the control handle of the deflecting mechanism in  FIGS. 2 a   - b.    
         FIG. 7 a    illustrates a side view of the locking trigger of the deflecting mechanism in  FIGS. 2 a   - b.    
         FIG. 7 b    illustrates a perspective view of the locking trigger of the deflecting mechanism in  FIGS. 2 a   - b.    
         FIG. 8 a    shows a partial cross-sectional side view of the deflectable access sheath before the deflector filament is retracted in a proximal direction. 
         FIG. 8 b    shows a partial cross-sectional side view of the deflectable access sheath as the deflector filament is retracted in a proximal direction. 
         FIG. 9 a    show the engagement of the locking mechanism before the locking trigger is translated in a downward direction. 
         FIG. 9 b    show the engagement of the locking mechanism after the locking trigger is translated in a downward direction. 
         FIG. 10  shows a side view of the locking mechanism as the brake pad engages with the tension gear. 
         FIG. 11 a    shows a partial side view of the deflectable access sheath before the locking trigger is actuated by the user. 
         FIG. 11   b  shows a partial side view of the deflectable access sheath after the locking trigger is actuated by the user. 
         FIG. 12 a    shows a side view of an alternative embodiment of the deflecting mechanism. 
         FIG. 12 b    shows a transparent alternate side view of an alternative embodiment of the deflecting mechanism. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The embodiments described in this disclosure will be discussed generally in relation to the use of deflectable sheaths in the manipulation and guidance of operating and imaging tools in urological procedures such as lithotripsy, but the disclosure is not so limited and may be applied to the use of other deflectable medical devices in procedures in other vasculature or other body vessels or lumens. 
     In the present application, the term “proximal” refers to a direction that is generally closest to the operator of the device during a medical procedure, while the term “distal” refers to a direction that is furthest from the operator of the device. 
     The present deflectable access sheath operates to allow the controlled deflection of the distal end of the deflectable access sheath away from a linear conformation. In particular, the deflectable access sheath may provide for a locking mechanism that locks the angle of the deflectable end of the deflectable access sheath. This locking mechanism allows for better control and use of the device during the procedure and allows the user to perform various other procedures during the ureteroscopy. The locking mechanism can be released to allow for the increased deflection of the deflectable end or for the deflectable end to return to a linear conformation. 
     The deflectable access sheath may further allow the deflection of the deflectable end while the deflectable access sheath is in a locked position. In one example, a ratcheting mechanism allows the incremental deflection of the deflectable end. Each incremental deflection is locked into place by the locking mechanism. This ratchet aspect allows the user on-the-spot modification of the deflection angle of the deflectable end. 
     Once the desired angle of the distal end of the deflectable access sheath is achieved, accessories and/or other medical devices, such as laser fibers, optical fibers, wire guides, stone-breakers, and/or stone removal tools, can be inserted through the working channel and used for that particular procedure. 
     The present device provides a handle design that allows the user to access the sheath closer to hip-level which allows the user to transfer more torque to twist the device and grip power to actuate the device. This results in less fatigue of the user. The handle design of the present device is more fully described with reference to U.S. application Ser. No. 29/461,908 (filed Jul. 29, 2013) and commonly assigned to the assignee of this application, which is hereby incorporated by reference in its entirety. 
     As described more fully below with regard to  FIGS. 1-3 , the sheath handle assembly  100  has a control handle  120  that accomplishes the above functions. The sheath handle assembly  100  is composed of four main parts—a sheath housing  110 , a control handle  120 , a locking trigger  150  and a gear locking system  160  that is composed of a tension gear  130  and a brake pad  140 . 
     In operation, the sheath housing  110  is held by the user and the control handle  120  is compressed in an upward direction. This upward compression translates into a clockwise rotational movement of the tension gear  130 . The movement of the tension gear  130  translates into the longitudinal movement of the tension wire  170  which causes deflection of the distal end of the sheath handle assembly  100  (not pictured here). The locking trigger  150  is actuated by a downward movement that engages the gear locking system  160 . This engagement brings the outer teeth of the brake pad  140  in contact with the inner teeth of the tension gear  130 . Subsequent compression of the control handle  120  results in the incremental movement of the tension wire  170  as defined by the inner teeth of the tension gear  130 . This provides for incremental adjustment of the deflection of the distal end of the sheath handle assembly  100  (not pictured here), while preventing the return of the distal end to a linear configuration. 
       FIGS. 1-3  illustrate an embodiment of the sheath handle assembly  100 .  FIGS. 4-7  illustrate components of an embodiment of the sheath handle assembly  100 .  FIGS. 8 a - b    illustrate the sheath handle assembly  100  as it is operated by a user to deflect the distal end of the sheath handle assembly  100 .  FIGS. 9-11  illustrate the sheath handle assembly  100  as the gear locking system  160  is actuated.  FIGS. 12 a - b    illustrate an alternative embodiment of the gear locking system  160  of  FIG. 1 . 
       FIGS. 1 a - b    show the multiple components of the sheath handle assembly  100  as they are interconnected.  FIG. 1 a    provides a proximal view of the sheath handle assembly  100  with sheath housing  110 , control handle  120 , and a portion of the locking trigger  150 . Connected to the distal end of the sheath handle assembly  100  is a lumen with a deflectable end (not pictured here) that will be further discussed in  FIGS. 8 a - b   .  FIG. 1 b    shows a cross-sectional view of the sheath handle assembly  100  that includes a sheath housing  110 , a control handle  120 , a gear locking system  160  which is made up of the tension gear  130  and the brake pad  140 , a locking trigger  150 , and a tension wire  170 . Each of the individual components of the sheath handle assembly  100  will be described in further detail below. 
       FIGS. 2 a - b    provide enlarged cross-sectional views of the locking mechanism  200  of the sheath handle assembly  100  and the interconnections of the various components of the sheath handle assembly  100 . The locking mechanism  200  includes the control handle  120 , the gear locking system  160  which is made up of the tension gear  130 , the brake pad  140 , and the locking trigger  150 . 
       FIG. 3  provides a cross-sectional view of the sheath housing  110  with receptors built into the inside of the sheath housing  110  to provide for the containment and controlled movement of the various components in the sheath handle assembly  100  as described in  FIGS. 1-2 . The control handle  120  is rotatably connected to the sheath housing  110  through a pin that is inserted through the control handle  120  and fits into the handle slot  310 . The pin connected through the handle slot  310  allows the control handle  120  rotational movement about the pin. The movement of the control handle  120  is further controlled by a pin that fits into handle movement slot  320  of the sheath housing  110 , described in further detail below. 
     The locking trigger  150  and the tension gear  130  is rotatably connected to the sheath housing  110  by a pin that is connected through the slot  330  of the sheath housing  110 . As will be described in further detail, the pin at slot  330  fits through the tension gear locking trigger  150  which is disposed about the tension gear  130 . 
     The brake pad  140  is connected to the sheath housing  110  through a pin that is rotatably connected to the sheath housing  110  through a pin that is inserted through the brake pad  140  and fits into the brake slot  340  of the sheath housing  110 . The pin connected through the brake slot  340  allows the brake slot  340  rotational movement about the pin. As will be discussed further, movement of the locking trigger  150  rotates the brake pad  140  to bring it in contact with tension gear  130 . 
     The sheath housing  110  of  FIG. 3  also provides for other connections that allows for the actuation of the locking trigger  150 . The actuating braking slot  360  provides for the protrusion of the locking mechanism actuator (not pictured here) to protrude from the sheath housing  110  so that it is visible to the user. The distal end of the locking trigger  150  fits into the locking trigger indicator slot  350  which limits the extent of the movement of the distal end of the locking trigger  150 . The locking trigger pin indicator  380  allows for the distal end of the locking trigger indicator slot  350  to be visible when the locking trigger  150  is actuated. The locking trigger  150  is prevented from moving by the locking trigger protrusion  370  which keeps the proximal end of the locking trigger  150  in either the non-actuated or actuated position. 
       FIGS. 4-7  illustrate the individual components of an embodiment of the sheath handle assembly  100 . 
       FIGS. 4 a - b    provide a side and perspective view of the tension gear  130  of the gear locking system  160  of  FIGS. 1 b  and 2 a - b   . In the present embodiment, the tension gear  130  has an outer surface  420  and an inner surface  410 . The tension gear  130  is rotatably connected to the sheath housing  110  through the opening  405  which is disposed about a pin that is connected to slot  330  of  FIG. 3 . 
     The outer surface  420  includes an outer engagement portion  470  and a portion for engaging the tension wire  170  of  FIG. 1   b . The outer engagement portion  470  is comprised of more than one tooth  440  and more than one tooth receiving end  445 . This outer engagement portion  470  engages a series of teeth on a portion of the control handle  120  which cause the outer engagement portion  470  to rotate when the control handle  120  is actuated. The outer surface  420  also includes a filament anchor  430  which protrudes from the outer surface  420 . The tension wire  170  of  FIG. 1 b    is attached to the filament anchor  430  at the filament connection  480  and rests in the filament receptor  490 . The filament receptor  490  is disposed between the filament anchor  430  and one end of the outer engagement portion  470 . The length of the filament receptor  490  is at least equal to the length of the tension wire  170  needed to cause the maximum deflection of the lumen. 
     The inner surface  410  has an inner engagement portion  460  that is composed of teeth to engage the teeth portion of the brake pad  140  shown in  FIGS. 5 a - b   . The inner engagement portion  460  includes more than one sawtooth  450  and more than one sawtooth receiving end  455 . As will be discussed below, when the inner engagement portion  460  is engaged, a ratcheting device is created. The shape of the sawtooth  450  and the sawtooth receiving end  455 , provide for movement in a single direction and restricts movement in a counterclockwise direction at each sawtooth  450 . 
       FIGS. 5 a - b    provide a side and perspective view of the brake pad  140  of the gear locking system  160  of  FIGS. 1 b  and 2 a - b   . In the present embodiment, the brake pad  140  has an outer surface  510  and two points of connection to the sheath housing  110 —an opening  520  and a slot portion  530  that define and restrict the movement of the brake pad  140 . 
     The brake pad  140  is rotatably connected to the sheath housing  110  through the opening  520  which is disposed about a pin that can be fit into the brake slot  340 . As will be further described below, the slot portion  530  is disposed about a pin that fits into the locking trigger  150 . When the locking trigger  150  is actuated in either an upward or downward direction, the brake pad  140  is rotated a limited distance as defined by the slot portion  530 . 
     The outer surface  510  of the brake pad  140  includes a ratchet portion  540  for engaging the inner engagement portion  460  of the tension gear  130 . The ratchet portion  540  is comprised of more than one tooth  550  and more than one tooth receiving end  560 . As described above, the shape of the tooth  550  and the tooth receiving end  560  act as a ratchet against the inner surface  410  of the brake pad  140 . When the ratchet portion  540  of the brake pad  140  is brought into contact with the inner surface  410  of the tension gear  130 , the tension gear  130  is allowed to move in a single direction, but the tooth  550  and the tooth receiving end  560  interact with the sawtooth  450  and sawtooth receiving end  455  of the tension gear  130  to prevent movement of the tension gear  130  in a counterclockwise direction at each sawtooth  450  and sawtooth receiving end  455  of the tension gear  130 . 
       FIGS. 6 a - b    provide a side and perspective view of the control handle  120  of  FIGS. 1 b  and 2 a - b   . In the present embodiment, the control handle  120  has a lever portion  650 , an engagement portion  620  on the outer surface  610  and two points of connection to the sheath housing  110 —an opening  660  and a slot portion  670  that define and restrict the movement of the control handle  120 . 
     The control handle  120  is rotatably connected to the sheath housing  110  through the opening  660  which is disposed about a pin that can fit into the handle slot  310 . The range of movement of the control handle  120  is limited by the slot portion  670 . A pin fits into the handle movement slot  320  of the sheath housing  110  and the slot portion  670  is disposed about this pin. When the lever portion  650  of the control handle  120  is pulled in an upward direction, the rotational movement of the control handle  120  is limited by the length of the slot portion  670 . Any or all embodiments of the lever portion  650  may be provided with gripping features that provide secure and/or ergonomic gripping of the handles by the user. Any or all of the handles may further be provided with a mechanism or ability to provide the user with tactile feedback while gripping and/or operating the handle. 
     The engagement portion  620  lies on the outer surface  610  of the control handle  120 . Engagement portion  620  is composed of more than one input tooth  630  and more than one input tooth receiving end  640 . As will be discussed, the input tooth  630  and the input tooth receiving end  640  of the engagement portion  620  interact with the more than one tooth  440  and more than one tooth receiving end  445  of the outer engagement portion  470  of the tension gear  130  to cause the tension gear  130  to rotate. When the gear locking system  160  is not engaged, actuating of the lever portion  650  causes the engagement portion  620  of the control handle  120  to interact with the outer engagement portion  470  of the tension gear  130  and rotation of the tension gear  130  in a clockwise direction when the lever portion  650  is compressed upwards and rotation of the tension gear  130  in a counterclockwise direction when the lever portion  650  is released. 
       FIGS. 7 a -7 b    provide a side and perspective view of the locking trigger  150 . In the present embodiment, the locking trigger  150  is composed of elements that control the movement of the locking trigger  150  and elements that actuate the gear locking system  160 . The locking trigger  150  has a locking mechanism actuator  710 , a tension gear engagement slot  720 , a brake pad engagement slot  730 , a locking trigger movement pin  740  and a distal pin  750 . 
     The locking trigger  150  is rotatably connected to the sheath housing  110  through the tension gear engagement slot  720  which is disposed about a pin that connects to the slot  330  of the sheath housing  110 . The locking trigger  150  is disposed about the tension gear  130  such that the pin that fits into slot  330  of the sheath housing  110  fits through both the tension gear engagement slot  720  and the opening  405  of tension gear  130 . The brake pad engagement slot  730  is operatively connected to the brake pad  140  by a pin that extends through the slot portion  530  of the brake pad  140 . The pin is connected on either end to the brake pad engagement slot  730  of the locking trigger  150 . 
     The locking mechanism actuator  710  provides the user with control of the movement of the locking trigger  150  and the engagement of the gear locking system  160 . The locking mechanism actuator  710  protrudes from the sheath housing  110  at the actuating braking slot  360  to allow the user to actuate the locking mechanism actuator  710  in the actuating braking slot  360 . Before the gear locking system  160  is engaged, the pin connected to the brake pad engagement slot  730  is adjacent to the slot top portion  532  of the brake pad  140 . The user can engage the gear locking system  160  by actuating the locking mechanism actuator  710  which moves the locking trigger  150  so that the pin connected to the brake pad engagement slot  730  is now adjacent to the slot bottom portion  534  of the brake pad  140 . The movement brings the brake pad  140  in contact with the tension gear  130 . As discussed above, this engages the gear locking system  160  and creates a ratcheting movement. The brake pad  140  allows movement of the tension gear  130  in a clockwise direction, but prevents the tension gear  130  from moving in a counterclockwise direction. As will be discussed below, when the gear locking system  160  is engaged, subsequent movement in a clockwise direction is limited in increments by the sawtooth  450  on the tension gear  130 . 
     The locking trigger  150  is prevented from moving—whether in its actuated state or non-actuated state—by the locking trigger protrusion  370  of  FIG. 3 . When the locking mechanism actuator  710  is actuated to engage or disengage the gear locking system  160 , the locking trigger movement pin  740  moves above and below either end of the locking trigger protrusion  370  of  FIG. 3  which protrudes above the surface of the sheath housing  110 . This protrusion prevents the locking trigger movement pin  740  from migrating, and therefore keeps the gear locking system  160  from unintentionally engaging or disengaging. 
     The distal end of the locking trigger  150  and the distal pin  750  is housed in the locking trigger indicator slot  350  of the sheath housing  110 . When the locking mechanism actuator  710  has been actuated to engage the gear locking system  160 , the distal pin  750  moves so that it rests in the locking trigger pin indicator  380  of the sheath housing  110 . The locking trigger pin indicator  380  is an opening in the sheath housing  110  that allows the distal pin  750  to be visible from outside the sheath housing  110 . When the locking mechanism actuator  710  has been actuated to engage the gear locking system  160 , the visibility of the distal pin  750  at the locking trigger pin indicator  380  provides the user with a visual cue that the gear locking system  160  has been engaged. 
     The sheath handle assembly  100  functions to deflect the distal end of the lumen attached to the distal end of the sheath handle assembly  100 .  FIGS. 8 a -8 b    illustrate the lumen  820  and the deflectable end  810  as it is deflected away from a linear position. As seen in  FIG. 8 a   , the control handle  120  can be compressed to bring it closer to the body of the sheath housing  110 . The engagement portion  620  of the control handle  120  interacts with the outer engagement portion  470  of the tension gear  130  to turn the tension gear  130  in a clockwise direction. The proximal end of the tension wire  170  is attached to the filament anchor  430  of the tension gear  130  and the distal end of the tension wire  170  is attached to the lumen  820 . As the tension gear  130  moves in a clockwise direction, the tension wire  170  moves in a proximal direction which causes the deflectable end  810  to deflect away from the linear configuration. As seen in  FIG. 8 b   , the deflectable end  810  can deflect in a single direction away from the linear configuration. When the control handle  120  is released so that it moves in a direction away from the sheath housing  110 , the tension gear  130  moves in a counterclockwise direction. The attached tension wire  170  then moves in a distal direction which causes the deflectable end  810  of the lumen  820  to return to a linear configuration. 
     The angle of deflection of the deflectable end  810  can be held in place, or adjusted in increments by engaging the gear locking system  160 .  FIGS. 9-11  illustrate the sheath handle assembly  100  as the gear locking system  160  is engaged. 
       FIG. 9 a    illustrates a cross-section of the sheath handle assembly  100  before the gear locking system  160  is engaged. As can be seen, before the gear locking system  160  is engaged, the pin in the brake pad engagement slot  730  of the locking trigger  150  is located adjacent to the slot top portion  532  of the slot portion  530  of the brake pad  140 . In this configuration, the ratchet portion  540  of the brake pad  140  has not engaged the inner engagement portion  460  of the tension gear  130 . This allows the control handle  120  to move freely in either direction—to turn the tension gear  130  in a clockwise or a counterclockwise direction (depending on whether the control handle  120  is being compressed or released). This movement slides the tension wire  170  in either a proximal or distal direction to cause the deflectable end  810  of the lumen  820  of  FIG. 8 b    to either deflect away from linear or to return to its linear configuration. 
       FIG. 9 b    illustrates a cross-section of the sheath handle assembly  100  after the gear locking system  160  is engaged. The locking mechanism actuator  710  is actuated in a downward direction. This movement causes the pin in the brake pad engagement slot  730  to move downward so that it lies adjacent to the slot bottom portion  534  of the slot portion  530  of the brake pad  140 . This causes the brake pad  140  to rotate about the pin in the opening  520  so that the ratchet portion  540  of the brake pad  140  is brought in contact with the inner engagement portion  460  of the tension gear  130 . 
     The distal pin  750  moves upward so that it comes in contact with the locking trigger pin indicator  380 . As mentioned above, this serves as an indicator to the user that the gear locking system  160  is engaged. The distal pin  750  may be colored differently than the sheath housing  110  or have some marking to provide a visual indicator to the user. 
     The locking trigger movement pin  740  interlocks with the locking trigger protrusion  370  to prevent unintentional movement of the locking trigger  150 . The locking trigger protrusion  370  is sloped to allow sliding of the locking trigger movement pin  740  into either configuration. However, without external force, the locking trigger movement pin  740  cannot move into another configuration. 
     When the gear locking system  160  is engaged, the shape of the teeth on the inner engagement portion  460  of the tension gear  130  and the teeth on the ratchet portion  540  of the brake pad  140  are sloped in a direction that prevent movement of the tension gear  130  in a counterclockwise direction. However, because of the sloped direction of the teeth, the control handle  120  can still be incrementally compressed to allow movement of the tension gear  130  in a clockwise direction. The angle of deflection of the deflectable end  810  can be secured at each increment on the inner engagement portion  460  as represented by each individual sawtooth  450 . 
     When the gear locking system  160  is disengaged, the locking mechanism actuator  710  is actuated in a upward direction which causes the pin in the brake pad engagement slot  730  to move upward so that it lies adjacent to the slot top portion  532  of the slot portion  530  of the brake pad  140 . When the gear locking system  160  is disengaged, the angle of deflection of the deflectable end  810  is no longer maintained and the control handle  120  is able to move freely. The tension gear  130  is able to move in both a clockwise and counterclockwise direction to either deflect the deflectable end  810  of the lumen  820  or to return the deflectable end  810  back into a linear configuration. 
       FIG. 10  provides an enlarged side view of the gear locking system  160  when it is engaged and the ratchet portion  540  of the brake pad  140  is in contact with the inner engagement portion  460  of the tension gear  130 . 
       FIGS. 11 a - b    provide a partial side view of the sheath handle assembly  100  before and after the gear locking system  160  has been engaged.  FIG. 11 a    shows the locking mechanism actuator  710  of the locking trigger  150  positioned within the actuating braking slot  360  before the gear locking system  160  is engaged.  FIG. 11   b  shows the locking mechanism actuator  710  of the locking trigger  150  within the actuating braking slot  360  after the gear locking system  160  is engaged.  FIGS. 11 a - b    also show the locking trigger pin indicator  380  which is visible to the user to indicate whether the gear locking system  160  is engaged. 
       FIGS. 12 a - b    provide a side view and a partial bottom view (wherein the friction tension gear  1210  is transparent for better viewing) of an alternate embodiment of the gear locking system  160 . The friction gear locking system  1200  of  FIGS. 12 a  and  b    is the same as the gear locking system  160  except the friction tension gear  1210  does not have any teeth on the surface of its inner surface  1220  and the friction brake pad  1250  does not have any teeth to engage the friction tension gear  1210  on its outer surface  1260 . 
     The friction tension gear  1210  has all the features of the tension gear  130  except for the inner engagement portion  460  of  FIGS. 4 a - b   . The friction tension gear  1210  pictured in  FIGS. 12 a - b    has an inner surface  1220  and an outer surface  1230 . The inner surface  1220  has a filament receptor  1280  that the tension wire  170  of  FIG. 1 b    rests upon. The outer surface  1230  has a chamfered edge  1240  that provides the friction tension gear  1210  with a better grip of the friction brake pad  1250  that it interacts with. 
     The friction brake pad  1250  has all the features of the tension gear  130  except it lacks the ratchet portion  540  of  FIGS. 5 a - b   . The friction brake pad  1250  pictured in  FIGS. 12 a - b    has an outer surface  1260  with a friction pad  1270  disposed partially over the outer surface  1260 . The friction pad  1270  may be composed of any soft elastomeric material such as rubber, polyisoprene, or thermoelastomers. 
     The friction gear locking system  1200  has the same function as the gear locking system  160  except that, in place of teeth, when the friction gear locking system  1200  is engaged, the friction pad  1270  of the outer surface  1260  is brought in contact with the chamfered edge  1240  of the inner surface  1220  of the friction tension gear  1210 . The friction force between the friction pad  1270  of the friction brake pad  1250  and the chamfered edge  1240  of the friction tension gear  1210  prevents the friction tension gear  1210  from moving in a counterclockwise direction. This embodiment does not have the discrete increments of the gear locking system  160  and therefore does not offer ratcheting. However, it provides for greater flexibility in controlling the deflectable end  810  of the lumen  820 . 
     While particular elements, embodiments, and applications of the present invention have been shown and described, it is understood that the invention is not limited thereto because modifications may be made by those skilled in the art, particularly in light of the foregoing teaching. It is therefore contemplated by the appended claims to cover such modifications and incorporate those features which come within the spirit and scope of the invention.