Patent Publication Number: US-2020276415-A1

Title: Steerable guiding sheath with rack and pinion deflection mechanism

Description:
CROSS-REFERENCE TO RELATED APPLICATION(S) 
     This application is a continuation of and claims priority to and the benefit of U.S. patent application Ser. No. 15/372,329 filed Dec. 7, 2016, now U.S. Pat. No. 10,653,860, the entire content of which is incorporated herein by reference. 
    
    
     FIELD OF INVENTION 
     This invention relates to a guiding sheath which is especially suitable for guiding electrophysiology catheter, in particular, a deflectable guiding sheath. 
     BACKGROUND 
     Guiding sheaths are well known for use in facilitating pathway for a treatment or diagnostic catheter. Catheterization of the human heart often necessitates having a catheter gain access to the heart chambers, via a femoral vein and the aorta. To provide variation in movement, guiding sheaths (much like the catheters that are passed through the guiding sheaths) may be steerable or deflectable with the use of one or more puller wires for improved maneuverability in the patient&#39;s vasculature. 
     Accordingly, there is a desire for a guiding sheath with improved deflection characteristics and smoother operation in deflection mechanisms of the control handle. 
     SUMMARY OF THE INVENTION 
     In some embodiments, a guiding sheath assembly comprises an elongated shaft and a control handle proximal of the shaft, the control handle having a longitudinal axis. The control handle includes a rotatable shaft, a pinion, and first and second shuttles. The shaft is configured for rotation about the longitudinal axis. The first shuttle configured for translation along the longitudinal axis in one direction in response to rotation of the rotatable shaft, wherein the first shuttle has a first plurality of teeth. The opinion is in engagement with the first plurality of teeth, and configured for rotation about an axis generally perpendicular to the longitudinal axis in response to the translation of the first shuttle. The second shuttle has a second plurality of teeth in engagement with the pinion and is configured for translation along the longitudinal axis in another direction opposite to the one direction in response to rotation of the pinion. The guiding sheath assembly also has a first puller wire extending along one side of the shaft and having a proximal end portion responsive to at least translation of the first shuttle in a proximal direction, and a second puller wire extending along another side of the shaft and having a proximal end portion response to at least translation of the second shuttle in the proximal direction. 
     In some embodiments, the control handle includes a control knob and the rotatable shaft being configured for rotation in response to rotation of the control knob. 
     In some embodiments, the rotatable shaft has an inner passage configured to receive a first distal portion of the first shuttle and a second distal portion of the second shuttle. 
     In some embodiments, the first and second distal portions are configured to form a cylindrical form when the first and second shuttles are laterally even with each other along the longitudinal axis. 
     In some embodiments, an inner surface of the inner passage is threaded and an outer surface of the first distal portion is threaded and engaged with the inner surface. 
     In some embodiments, the rotational shaft is rotationally and translationally coupled to the control knob. 
     In some embodiments, the rotational shaft is rotationally coupled to the control knob by a longitudinal ridge formed on an outer surface of the shaft. 
     In some embodiments, the rotational shaft is rotationally coupled to the control knob by a pin extending through a portion of the control knob and slot formed in the rotational shaft. 
     In some embodiments, the rotational shaft is rotationally and translationally coupled to the control knob at its distal end. 
     In some embodiments, the control handle includes a neutral indicator. 
     In some embodiments, the neutral indicator includes a first member on the first shuttle and a second member on the second shuttle, wherein the first and second members are configured for releasable engagement. 
     In some embodiments, the neutral indicator is configured to provide resistance to disengagement and re-engagement. 
     In some embodiments, the first neutral indicator includes a tapered projection, and the second neutral indicator includes a tapered recess. 
     In some embodiments, a guiding sheath assembly comprises an elongated shaft, and a control handle proximal of the shaft. The control handle has a longitudinal axis, and includes a control knob configured for rotation about the longitudinal axis, and a hollow rotatable shaft configured for rotation about the longitudinal axis in response to rotation of the control knob. The control handle also includes a first shuttle configured for translation along the longitudinal axis in one direction in response to rotation of the rotatable shaft, the first shuttle having a first plurality of teeth, a pinion in engagement with the first plurality of teeth, the pinion configured for rotation about an axis generally perpendicular to the longitudinal axis in response to the translation of the first shuttle, and a second shuttle having a second plurality of teeth in engagement with the pinion, the second shuttle configured for translation along the longitudinal axis in another direction opposite to the one direction in response to rotation of the pinion. The guiding sheath assembly further has a first puller wire extending along one side of the shaft and having a proximal end portion responsive to at least translation of the first shuttle in a proximal direction, and a second puller wire extending along another side of the shaft and having a proximal end portion response to at least translation of the second shuttle in the proximal direction. 
     In some embodiments, a control handle for use in controlling deflection of a medical guiding sheath shaft, includes a control knob configured for rotation about a longitudinal axis of the control handle, and a hollow rotatable shaft configured for rotation about the longitudinal axis in response to rotation of the control knob. The control handle also includes a first shuttle configured for translation along the longitudinal axis in one direction in response to rotation of the rotatable shaft, wherein the first shuttle has a first plurality of teeth. The control handle further includes a pinion in engagement with the first plurality of teeth, wherein the pinion is configured for rotation about an axis generally perpendicular to the longitudinal axis in response to the translation of the first shuttle. The control handle also includes a second shuttle having a second plurality of teeth in engagement with the pinion, the second shuttle configured for translation along the longitudinal axis in another direction opposite to the one direction in response to rotation of the pinion, wherein the first and second shuttles are configured to respectively act first and second puller wires extending along the guiding sheath shaft. 
     In some embodiments, distal ends of the first and second shuttles extend into a proximal portion of the rotatable shaft. 
     In some embodiments, an inner surface of the rotatable shaft is threaded and an outer surface of the first shuttle is threaded for rotationally coupling the rotatable shaft and the first shuttle. 
     In some embodiments, the first shuttle is directly responsive to rotation of the rotatable shaft and the second shuttle is directly responsive to rotation of the pinion. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       These and other features and advantages of the present invention will be better understood by reference to the following detailed description when considered in conjunction with the accompanying drawings. It is understood that selected structures and features have not been shown in certain drawings so as to provide better viewing of the remaining structures and features. 
         FIG. 1  is a top plan view of a guiding sheath including a control handle, in accordance with an embodiment of the present invention. 
         FIG. 2  is a longitudinal cross-sectional view of a control handle of  FIG. 1 . 
         FIG. 3  is an exploded view of the control handle of  FIG. 1 , with a housing removed. 
         FIG. 4  is a longitudinal cross-sectional view of a distal portion of the control handle of  FIG. 1 , including a control knob. 
         FIG. 5  is a perspective view of the control handle of  FIG. 1 , with the housing removed. 
         FIG. 6A  is a top plan view of a neutral indicator with first and second members engaged, in accordance with one embodiment of the present invention. 
         FIG. 6B  is a top plan view of the neutral indicator of  FIG. 6A  with the first and second members disengaged. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to  FIG. 1 , in some embodiment embodiments of present invention, a guiding sheath assembly  10  includes an elongated and flexible sheath  12 , and a control handle  16  proximal of sheath  12 . The sheath  12  includes a proximal section  13  and a distal deflection section  14 . The control handle  16  may be connected to an electrical connector  17  for transmitting electrical signals, as sensed by one or more ring electrodes carried on the sheath  12 , including, for example, the deflection section  14 . Also attached to the control handle  16 , as shown in  FIG. 1 , is a hemostatic valve  18  adapted to receive a catheter (not shown) that can be advanced through a center lumen  22  of the guiding sheath assembly  10  (fix  FIG. 1 ). The hemostatic valve  18  also has side port  21  terminating in a luer hub, such as a two-way stop cock  23 , for connection to one or more fluid sources (not shown) for providing fluid into and through the lumen  22  of the guiding sheath assembly  10 . 
     As shown in  FIG. 2  and  FIG. 3 , the control handle  16  includes an elongated, generally cylindrical main body  24  with a narrower distal portion or stem  25 , and a distal rotational control knob  26  mounted on the distal portion stem  25 . The main body  24  has an outer shell-half member formed to define an interior volume V and whose edges  51  meet along a longitudinal seam. The distal stem  25  of the main body has a smaller outer diameter D 1  compared to the outer diameter D 2  of a proximal portion of the main body  24 . The control knob  26  is configured for rotation by a user&#39;s thumb and forefinger when the user is grasping the main body  24  of the control handle  16 . To enable deflection of the deflection section  14  of the guiding sheath  12  via first and second puller wires  30 A and  30 B, the control handle  16  includes in its interior volume V a rotatable shaft  31 , first and second shuttles  32 A and  32 B, and a pinion  34 . The rotatable shaft  31  is responsive to the control knob  26  in driving first shuttle  32 A to move linearly along a longitudinal axis  55  in a first direction, and the pinion  34  couples the second shuttle  32 B to the first shuttle  32 A such that the second shuttle  32 B moves linearly along the longitudinal axis in a second direction opposition to the first direction. With proximal ends of the first and second puller wires  30 A and  30 B anchored, or at least coupled, to the first and second shuttles  32 A and  32 B, respectively, such coupled and opposite translational movement of the first and second shuttles actuate the first and second puller wires for bi-directional deflection of the deflection section  14  of the guiding sheath  12 . 
     The rotatable shaft  31  has a main proximal section  36  with an outer diameter D 3 , a shorter distal section  37  with an outer diameter D 4 , and a step junction J therebetween between sections  36  and  37 . In the illustrated embodiment, the diameter D 3  is greater than the diameter D 4 , but it is understood that the two diameters may be generally equal or the diameter D 4  may be greater than the diameter D 3 . As better seen in  FIG. 2 , the rotatable shaft  31  is situated relative to main body  24  of the control handle  16  such that its proximal section  36  extends through both the main body  24  and the distal stem  25  of the control handle  16  and past a distal end of the distal stem  25 , with the junction J and the distal section  37  being distal of the distal stem  25  of the main body  24  so that the distal section  37  is not surrounded by the distal stem  25 . The rotatable shaft  31  is connected and affixed at its proximal end to the main body  24  by a proximal outer circumferential lip  38  that engages with an inner circumferential slot defined between circumferential flanges  40  formed in the interior volume V of the main body  24 . 
     With reference to  FIG. 4 , the rotatable shaft  31  is hollow having an interior passage  42 . The passage  42  is in communication with a distal inlet  44  whose diameter is merely slightly greater than the diameter of the guiding sheath  12 . The passage  42  is threaded and has a diameter to accommodate both the guiding sheath  12  and the shuttles  32 A and  32 B circumferentially surrounding the guiding sheath  12 , as discussed below in further detail. 
     The control knob  26 , which is mounted on the distal stem  25  of the main body  24  of the control handle  16  and the rotatable shaft  31 , has a main proximal portion  46  and a short distal end portion  47 . The control knob  26  is generally cylindrical with a longitudinal hollow interior that extends through its entire length. The hollow interior has a main proximal section  49 , a mid-section  49 ′ and a distal section  49 ″. The main proximal section  49  of the hollow interior is defined by a greater first radius R 1  and a greater first length L 1  to accommodate and circumferentially surround the guiding sheath  12  and the shuttles  32 A and  32 B. The distal section  49 ″ of the hollow interior is defined by a lesser second radius R 2 , where R 1 &gt;R 2 , and a shorter second length L 2 , where L 1 &gt;L 2 , to accommodate and circumferentially surround the guiding sheath  12  and the distal section  37  of the rotatable shaft  31 . The mid-section  49 ′ of the hollow interior is defined by a third radius R 3 , where R 1 &gt;R 3 &gt;R 2 , and a third length L 3 , where L 1 &gt;L 3 , to accommodate and circumferentially surround the guiding sheath  12  and the junction J of the rotatable shaft  31 . A friction-inducing cover  60  may be mounted on an outer surface of the control knob  26  for the user&#39;s ease and comfort in manipulating and rotating the control knob relative to the main body  24  of the control handle  16 . 
     To rotationally couple the rotatable shaft  31  to the control knob  26  (for common rotational movement of the rotatable shaft  31  and control knob  26 ), an outer surface of the distal section of the shaft has a longitudinal ridge  70  ( FIG. 3 ) that is received in and engages with a corresponding longitudinal recess  71  ( FIG. 4 ) formed an inner surface defining the hollow interior  49 ″ of the control knob  26 . To translationally affix the control knob  26  to the rotatable shaft  31  (for common translational movement of the control knob  26  and rotatable shaft  31 ) and hence the main body  24 , the outer surface of the shaft  31  also has one or more linear slots  74  oriented perpendicularly to the longitudinal axis of the rotatable shaft  31 . Each slot  74  is aligned with a respective hole  76  ( FIG. 5 ) formed through a side of the distal end portion  47  of the control knob  26 , so that a respective pin  77  may be inserted into the hole  76  and the slot  74  to couple the control knob  26  and the rotatable shaft  31  for common translational movement. 
     It is understood that other embodiments of the guiding sheath assembly may provide a rotatable shaft  31  with an exposed portion for direct manipulation by a user, without the control knob  26 . 
     As shown in  FIG. 3  and  FIG. 5 , the shuttles  32 A and  32 B have a similar construction to each other, with the understanding that each is generally a mirror image of the other, although the first shuttle  32 A is driven by the rotatable shaft  31  and second shuttle  32 B is driven by the first shuttle  32 A via the pinion  34  situated between them. Each shuttle  32 A and  32 B has a respective elongated body having a distal portion  80 A and  80 B with a C-shaped end cross-section, and a respective proximal rack portion  90 A and  90 B with a respective plurality of teeth  92 A and  92 B arranged longitudinally. The first and second shuttles are arranged to face each other and engage the pinion  34  such that the distal portions  80 A and  80 BC together can form a cylindrical form with an outer circumferential surface that fits within the threaded passage  42 , and an inner circumferential surface that defines a passage  93  for the guiding sheath  12  to pass through. As shown in  FIG. 5 , the rack portion  90 A and  90 B of each shuttle faces each other with the pinion  34  in between so that the teeth  92 A and  92 B of each rack portion can engage with teeth of the pinion  34  which is mounted for rotation about an axis perpendicular to the longitudinal axis  55  of the control handle  16 . 
     With reference to  FIG. 2  and  FIG. 3 , an outer surface of the distal portion  80 A of the first shuttle  32 A is configured with an external or male threaded surface  85 . An inner circumferential surface of the rotatable shaft  31  is configured with an internal or female threaded surface  86  ( FIG. 4 ) which receives the male threaded surface  85  of the first shuttle  32 A for coupling the first shuttle  32 A and the rotatable shaft  31  in converting rotational movement of the rotatable shaft  31  into translation movement of the first shuttle  32 A. In contrast, the outer surface of the distal portion  80 B of the second shuttle  32 B is smooth, without any feature engaging the threaded female surface of the rotatable, so that it can move independently of the threaded male surface  85 . Accordingly, as a user rotates the control knob  26  in a first direction, the rotatable shaft  31  which is rotationally coupled to the control knob  26  (for common rotational movement) via the longitudinal ridge  70  also rotates. With the rotatable shaft  31  rotationally and translationally locked to the control knob  26  (for common rotational and common translational movement) via the longitudinal ridge  70  and the one or more pins  77 , rotation of the shaft  31  drives the first shuttle  32 A to translate along the longitudinal axis in a first direction (for example, proximally). As the first shuttle  32 A translates, its teeth  92 A drive the pinion  34  to rotate in a first direction (for example, clockwise), which in turn drives the second shuttle  32 B to translate along the longitudinal axis  55  in a second direction opposite of the first direction (for example, distally). So arranged, the male and female threaded surfaces  85  and  86  convert rotational movement of the control knob  26  into linear movement of the shuttles  32 A and  32 B. With proximal ends of the first and second puller wires  30 A and  30 B anchored, coupled or otherwise responsive to the first and second shuttles  32 A and  32 B, respectively, linear and opposite movements of the shuttles actuate the puller wires for bi-directional deflection of the deflection section  14  of the guiding sheath  12 . In the illustrated embodiment, the proximal ends of the puller wires  30 A and  30 B are coupled to the rack portions  90 A and  90 B of the shuttles  32 A and  32 B, respectively. Thus, when one puller wire is drawn proximally under tension by its respective shuttle, the other puller wire is simultaneously released from tension by its respective shuttle moving distally. 
     As shown in  FIG. 2 , a proximal end segment of each puller wire  30 A and  30 B extends outside of the sheath  12 , in a respective longitudinal channel  88 A and  88 B formed in the proximal rack portion  90 A and  90 B of each shuttle  32 A and  32 B. As shown in  FIG. 5 , a stop  89 A and  89 B, for example, a hypotube, is affixed to the proximal end of each puller wire  30 A and  30 B, and the stop is positioned proximal of a proximal end  87 A and  87 B of the respective rack portion  90 A and  90 B so that the rack portion can push or otherwise act on the stop  89 A and  89 B, respectively, to draw the puller wire  30 A and  30 B proximally when the shuttle  32 A and  32 B is moved proximally. When a shuttle  32 A and  32 B is moved distally, the proximal end of the rack portion  90 A and  90 B comes out of contact with the stop  89 A and  89 B, releasing the puller wire  30 A and  30 B from tension. It is understood that the stop  89 A and  89 B may also be embedded or otherwise anchored to the rack portion or any part of the shuttle to effect deflection of the sheath. 
     Because the first and second shuttles  32 A and  32 B move in opposite directions along the longitudinal axis  55 , an initial positioning of the shuttles relative to each other and to the passage  42  is made during assembly of the control handle. For example, as shown in  FIG. 2 , each shuttle is positioned in the passage  42  of the rotatable shaft  31  such that they are even with each other along the longitudinal axis  55 , and each has a distal end positioned generally at mid-point along the passage  42  so that each shuttle has sufficient room to move correspondingly proximally or distally within the rotatable shaft  31 . The stops  89 A and  89 B may be positioned relative to the shuttles such that there is minimal or even tension exerted on each puller wire  30 A and  30 B for a generally neutral guiding sheath with little, if any, deflection. So arranged, the shuttles adopt a “neutral” or initial configuration from which the user may evenly deflect the guiding sheath bi-directionally. 
     As shown in  FIG. 5 , the pinion  34  is positioned in between and relative to the shuttles  32 A and  32 B so that their teeth  92 A and  92 B remain engaged while the shuttles translate in response the user&#39;s manipulation of the control knob  26 . In that regard, the length of the rack portions  90 A and  90 B are sufficiently long to ensure such continuous engagement. 
     It is understood that by changing one or more factors, including, for example, the length of the passage  42 , the length of each distal portion  80 A and  80 B, the length of the rack portion  90 A and  90 B, the position of the pinion  34 , and the number of pinions, different shuttle movement and deflection characteristics and limitations may be achieved, as needed or desired. 
     With reference to  FIG. 6A  and  FIG. 6B , an outer surface of each rack portion  90 A and  90 B, opposite of the teeth  92 A and  92 B, of each shuttle  32 A and  32 B is configured with a neutral indicator. The neutral indicator includes a first member  62 A and a second member  62 B configured for releasable engagement with each other to indicate a neutral position between the first and second shuttles  32 A and  32 B, that is, a relative position where the puller wires  30 A and  30 B are neutral and the guiding sheath  12  accordingly is generally straight, without deflection. In the illustrated embodiment, the first or male member  62 A formed on the first shuttle  32 A has a tapered projection  63  facing the second or female member  62 B formed on the second shuttle  32 B, which includes a pair of flexible guide rails  64  on either side, whose fixed ends  65  are affixed to the second shuttle  32 B and whose free ends  66  are configured to jointly form a tapered recess  67  in which the tapered projection  63  nests when the shuttles  32 A and  32 B are in the neutral configuration. 
     Accordingly, the user is typically initially presented with the guiding sheath  12  undeflected where the first and second shuttles  32 A and  32 B are even with each other with the tapered projection  63  nesting in the tapered recess  67 , as shown in  FIG. 6A . When the user rotates the control knob  26  in one direction which drives the first and second shuttles  32 A and  32 B to translate in opposition directions, as shown in  FIG. 6B , the tapered projection  63  disengages and moves out from the tapered recess  67  but only when the user rotates the control knob with sufficient force to flex the guide rails  64  and overcome the resistance presented by their angled ends  68 . When the tapered projection  63  rides over and has moved past one of the angled ends  68 , the guide rail  64  is sloped such that the resistance to movement of the tapered projection  63  decreases as the tapered projection  63  moves further away from the tapered recess  67 . Thus, in rotating the control knob  26  to deflect the guiding sheath  12 , the user experiences a greater or maximum resistance when the shuttles  32 A and  32 B initially move out of the neutral configuration, followed by increasing ease as the shuttles  32 A and  32 B translate in opposite directions. The control handle  16  may bear visual and/or tactile indicia to provide constant orientation of deflection direction. For example, clockwise rotation of the control knob  26  consistently deflects the shaft  12  toward the side or direction of the sideport  21 , and counterclockwise rotation of the control knob  26  consistently deflects the shaft  12  toward an opposite side or direction. 
     Conversely, when releasing the deflection of the guiding sheath  12 , the user rotates the control knob  26  in the opposite direction. As the shuttles  32 A and  32 B translate and approach each other and begin to laterally realign again, the tapered projection  63  and the tapered recess  67  approach each other and the user applies an increasing force to rotate the control knob  26  in order for the tapered projection  63  to ride back over the angled end  68  of a guide rail  64  before the tapered projection  63  can nest in the tapered recess  67 . Accordingly, the increasing resistance posed by either of the sloped rails  64  and a greater or maximum resistance posed by an angled end  68  provides the user with a tactile feel or indication of when the tapered projection  63  is in the immediate proximity of the tapered recess  67 . Engagement of the tapered projection  63  and the tapered recess  67  can provide the user with an audible “click” or signal when the flexible guide rail  64  snaps into its natural configuration when the tapered projection  63  no longer exerts any load on it. 
     The preceding description has been presented with reference to presently preferred embodiments of the invention. Workers skilled in the art and technology to which this invention pertains will appreciate that alterations and changes in the described structure may be practiced without meaningfully departing from the principal, spirit and scope of this invention. Any feature or structure disclosed in one embodiment may be incorporated in lieu of or in addition to other features of any other embodiments, as needed or appropriate. As understood by one of ordinary skill in the art, the drawings are not necessarily to scale. Accordingly, the foregoing description should not be read as pertaining only to the precise structures described and illustrated in the accompanying drawings, but rather should be read consistent with and as support to the following claims which are to have their fullest and fair scope.