Patent Publication Number: US-2023145460-A1

Title: Steerable medical device, handle for a medical device, and method for operating a medical device

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application is a continuation application of International Application No. PCT/IB2021/056055, filed Jul. 6, 2021, titled “STEERABLE MEDICAL DEVICE, HANDLE FOR A MEDICAL DEVICE, AND METHOD FOR OPERATING A MEDICAL DEVICE,” which claims priority to U.S. Provisional Application No. 63/049,202, filed Jul. 8, 2020, titled “STEERABLE MEDICAL DEVICE, HANDLE FOR A MEDICAL DEVICE, AND METHOD FOR OPERATING A MEDICAL DEVICE,” the entire disclosures of which are incorporated herein by reference. 
    
    
     FIELD 
     This document relates to medical devices. More specifically, this document relates to steerable medical devices such as steerable sheaths, catheters, and introducers. 
     SUMMARY 
     The following summary is intended to introduce the reader to various aspects of the detailed description, but not to define or delimit any invention. 
     Steerable medical devices are disclosed. According to some aspects, a steerable medical device includes a handle having a rotatable knob assembly and housing a slide assembly. The knob assembly is couplable to the slide assembly to drive movement of the slide assembly by rotation of the knob assembly. An elongate tool extends from the handle. At least one control wire is coupled between the slide assembly and the tool. Movement of the slide assembly causes tensioning of the control wire, and tensioning of the control wire causes deflection of the tool. A slip clutch assembly is between the knob assembly and the slide assembly. When torque applied to the knob assembly is below a threshold value, the slip clutch assembly couples the knob assembly to the slide assembly to drive movement of the slide assembly by rotation of the knob assembly. When torque applied to the knob assembly is above the threshold value, the slip clutch assembly decouples the knob assembly from the slide assembly to prevent movement of the slide assembly by rotation of the knob assembly. 
     In some examples, the slip clutch assembly includes a first disc rotatable with the knob assembly and having a first engagement face, and a second disc configured to transmit rotation to the slide assembly and having a second engagement face. At least one of the first disc and the second disc can translate between a first position and a second position. In the first position, the first engagement face and the second engagement face are engaged to couple the rotatable knob to the slide assembly. In the second position the first engagement face and the second engagement face are disengaged to decouple the rotatable knob from the slide assembly. 
     In some examples, the first disc is fixed with respect to the knob assembly, and the second disc is coupled to the slide assembly and is translatable between the first position and the second position. 
     In some examples, the slip clutch assembly further includes a driveshaft fixed to the slide assembly and extending towards the rotatable knob. The driveshaft can include a plurality of splines. The second disc can be annular and can include an inner surface having a plurality of longitudinal grooves. The second disc can be received on the drive shaft with the splines engaged with the grooves. 
     In some examples, the slip clutch assembly further includes a spring biasing the second disc towards the first position. The slip clutch assembly can further include a flange from which the driveshaft extends. The spring can be received on the driveshaft and can be compressed between the flange and the second disc. 
     In some examples, the first engagement face has a first set of teeth, and the second engagement face has a second set of teeth, and the first set of teeth and the second set of teeth each have inclined side surfaces to facilitate movement from the first position to the second position by rotation of the first disc. 
     In some examples, the second disc is longitudinally fixed with respect to the first disc. When torque applied to the knob assembly is below a threshold value, the first disc can transmit rotation to the second disc by magnetic forces or frictional forces between the first engagement face and the second engagement face. 
     In some examples, the tool is a sheath, a catheter, or an introducer. 
     Handles for medical devices are also disclosed. According to some aspects, a handle for a medical device includes a rotatable knob assembly and houses a slide assembly. The knob assembly is couplable to the slide assembly to drive movement of the slide assembly by rotation of the knob assembly. A slip clutch assembly is between the knob assembly and the slide assembly. The slip clutch assembly includes a first disc and a second disc. The first disc has a first engagement face and is rotatable with the knob assembly. The second disc has a second engagement face and is configured to transmit rotation to the slide assembly. The first engagement face and the second engagement face are engageable to couple the rotatable knob to the slide assembly to drive movement of the slide assembly by rotation of the knob assembly, and are disengageable to decouple the rotatable knob and the slide assembly to prevent movement of the slide assembly by rotation of the knob assembly. 
     In some examples, at least one of the first disc and the second disc is translatable with respect to the slide assembly between a first position and a second position. In the first position, the first engagement face and the second engagement face can be engaged to couple the rotatable knob to the slide assembly. In the second position, the first engagement face and the second engagement face can be disengaged to decouple the rotatable knob from the slide assembly. 
     In some examples, the first disc is fixed to the knob assembly, and the second disc is coupled to the slide assembly and is translatable between the first position and the second position. 
     In some examples, the slip clutch assembly further includes a driveshaft fixed to the slide assembly and extending towards the knob assembly. The driveshaft can include a plurality of splines. The second disc can be annular and can include an inner surface having a plurality of longitudinal grooves. The second disc can be received on the drive shaft with the splines engaged with the grooves. 
     In some examples, the slip clutch assembly further includes a spring biasing the second disc towards the first position. The slip clutch assembly can further include a flange from which the driveshaft extends, and the spring can be received on the driveshaft and be compressed between the flange and the second disc. 
     In some examples, the first engagement face has a first set of teeth and the second engagement face has a second set of teeth. The first set of teeth and the second set of teeth can each have inclined side surfaces to facilitate translation from the first position to the second position by rotation of the first disc. 
     In some examples, the second disc is longitudinally fixed with respect to the first disc. The first engagement face and second engagement face can be engageable by magnetic forces or frictional forces. 
     Methods for operating medical devices are also disclosed. According to some aspects, a method for operating a medical device includes: a. with a knob assembly of the medical device coupled to a slide assembly of the medical device via a slip clutch assembly, applying torque to the knob assembly to rotate the knob assembly; and b. transmitting rotation of the knob assembly to the slide assembly via the slip clutch assembly. 
     In some examples, the slip clutch assembly includes a first disc having a first engagement face and a second disc having a second engagement face engagable with the first engagement face. The first disc can be rotatable with the knob assembly, and the second disc can be configured to transmit rotation to the slide assembly. Step b. can include transmitting rotation of the knob assembly to the first disc, transmitting rotation of the first disc to the second disc, and transmitting rotation of the second disc to the slide assembly. 
     In some examples, the second engagement face is maintained in engagement with the first engagement face by a spring. In some examples, the second engagement face is maintained in engagement with the first engagement face by frictional forces or magnetic forces. 
     In some examples, the method further includes: c. increasing the torque applied to the knob assembly to exceed a threshold value; and d. as a result of step c., decoupling the knob assembly from the slide assembly via the slip clutch assembly. 
     In some examples, the slip clutch assembly includes a first disc having a first engagement face and a second disc having a second engagement face engagable with the first engagement face. The first disc can be rotatable with the knob assembly, and the second disc can be configured to transmit rotation to the slide assembly. Step d. can include moving the second disc away from the first disc to disengage the first engagement face and the second engagement face. Moving the second disc away from the first disc can include translating the first disc along a driveshaft of the slip clutch assembly to compress a spring. 
     In some examples, the method further includes: e. decreasing the torque applied to the knob assembly to fall below the threshold value; and f. as a result of step e., recoupling the knob assembly to the slide assembly via the slip clutch assembly. 
     In some examples, the slip clutch assembly includes a first disc having a first engagement face and a second disc having a second engagement face engagable with the first engagement face. The first disc can be rotatable with the knob assembly, and the second disc can be configured to transmit rotation to the slide assembly. Step f. can include moving the second disc towards the first disc to engage the first engagement face and the second engagement face. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings are for illustrating examples of articles, methods, and apparatuses of the present disclosure and are not intended to be limiting. In the drawings: 
         FIG.  1    is a perspective view of an example medical device; 
         FIG.  2    is a cutaway plan view of the handle of the medical device of  FIG.  1   ; 
         FIG.  3    is an enlarged plan view of a slip clutch assembly of the handle of  FIG.  2    showing coupling of a knob assembly to a slide assembly by the slip clutch assembly; 
         FIG.  4    is an enlarged plan view similar to that of  FIG.  3   , showing decoupling of the knob assembly from the slide assembly by the slip clutch assembly; 
         FIG.  5    is an enlarged plan view similar to that of  FIG.  4   , showing recoupling of the knob assembly to the slide assembly by the slip clutch assembly; 
         FIG.  6    is a partial exploded view of the knob assembly, slip clutch assembly, and slide assembly of the handle of  FIG.  2   ; and 
         FIG.  7    is a bottom view of the second ring of  FIG.  6   . 
     
    
    
     DETAILED DESCRIPTION 
     Various apparatuses or processes or compositions will be described below to provide an example of an embodiment of the claimed subject matter. No example described below limits any claim and any claim may cover processes or apparatuses or compositions that differ from those described below. The claims are not limited to apparatuses or processes or compositions having all of the features of any one apparatus or process or composition described below or to features common to multiple or all of the apparatuses or processes or compositions described below. It is possible that an apparatus or process or composition described below is not an embodiment of any exclusive right granted by issuance of this patent application. Any subject matter described below and for which an exclusive right is not granted by issuance of this patent application may be the subject matter of another protective instrument, for example, a continuing patent application, and the applicants, inventors or owners do not intend to abandon, disclaim or dedicate to the public any such subject matter by its disclosure in this document. 
     Generally disclosed herein are steerable medical devices that include a handle and a tool such as a sheath, a catheter, or an introducer. The handle can enable the user to manipulate or steer the tool in a desired direction. More specifically, the handle can include a knob assembly that is rotatably coupled to a housing of the handle. In operation, the rotation of the knob assembly in a first rotational direction can allow the user to steer or deflect the tool in a first direction, whereas the rotation of the knob assembly in a second rotational direction can allow the user to steer or deflect the tool in a second direction. The rotation of the knob can be converted into a deflection of the tool via a slide assembly, which can be within the housing, and one or more control wires, which are connected between the slide assembly and the tool. The slide assembly can include a threaded shaft (also referred to as a bolt), and a slider (also referred to as a carriage) that is slidable on the threaded shaft. Rotation of the knob can cause rotation of the threaded shaft, which can cause linear translation of the slider along the threaded shaft. This translation of the slider causes a tensioning of the control wire(s), which results in a deflection of the tool. For simplicity, details of the slider and the control wires are not disclosed herein. However, related sliders and control wires are disclosed in, for example, U.S. Pat. No. 10,661,057 (Davies et al.), which is incorporated herein by reference in its entirety. Furthermore, steerable medical devices including sliders and control wires are sold Baylis Medical Company, Inc. (Montreal, Canada) under the brand name SureFlex® Steerable Guiding Sheath. 
     The steerable medical devices disclosed herein are configured to avoid or prevent or reduce the risk of failure due to excessive tension being applied to the control wire(s). Such excessive tension can occur, for example, if a stiff secondary tool is within the tool, preventing deflection of the tool, but a user attempts to force rotation of the knob assembly. Such excessive tension can further occur if the tool is caught on patient anatomy and thus cannot deflect, but a user attempts to force rotation of the knob assembly. Such excess tension can further occur if force is applied to the tool without rotating the knob, for example if the tool is pressed by patient anatomy. 
     In the devices disclosed herein, to avoid or prevent or reduce the risk of failure due to excessive tension being applied to the control wire(s), a slip clutch assembly is provided between the knob assembly and the slide assembly. In use, when a relatively low amount of tension is on the control wires and torque is applied to the knob assembly (i.e. torque of below a threshold value), the knob assembly rotates, and rotation of the knob assembly causes rotation of the slide assembly via the slip clutch assembly, which couples the knob assembly and the slide assembly; however, when the amount of tension on the control wires is relatively high and torque is applied to the knob assembly (i.e. torque of above the threshold value), the slip clutch assembly decouples the knob assembly from the slide assembly, to prevent rotation of the slide assembly with the knob assembly, and thereby prevent additional tension from being applied to the control wires. This can in turn avoid or prevent or reduce the risk of breaking of the control wires or disconnection of the joint between the control wires and the slide mechanism and/or tool. Furthermore, this can avoid or prevent or reduce the risk of tissue damage if the tool is caught on patient anatomy. 
     As used herein, the term “slip clutch assembly” refers to an assembly that couples a first element (e.g. a knob assembly) to a second element (e.g. a slide assembly) to transmit rotation from the first element to a second element when the torque applied to the first element is below a threshold value, and decouples the first element and the second element to prevent transmission of rotation from the first element to the second element when the torque applied to the second element is above a threshold value. 
     Referring now to  FIG.  1   , an example steerable medical device  100  is shown. The steerable medical device  100  generally includes a handle  102  and an elongate tool  104  extending from the handle. The tool  104  can be, for example (but not limited to), a sheath, a catheter, or an introducer. The handle  102  includes a rotatable knob assembly  106 , which can be rotated to steer the tool  104 . Rotation of the knob assembly  106  in a first direction (e.g. clockwise) can cause the tool  104  to deflect in a first direction (i.e. to the configuration shown in dotted line in  FIG.  1   ), and rotation of the knob assembly  106  in a second direction (e.g. counter-clockwise) can cause the tool  104  to deflect in a second direction (i.e. back to the configuration shown in solid line in  FIG.  1   ). 
     Referring still to  FIG.  1    and also to  FIG.  2   , the knob assembly  106  includes an outer knob  108  (shown in  FIG.  1   ), which is grasped and manipulated by the user, and an inner knob  110  (shown in  FIG.  2   ) which is rotated by rotation of the outer knob  108 . 
     Referring still to  FIG.  2   , a slide assembly  112  is housed within the handle  102 . As will be described in further detail below, the knob assembly  106  (only the inner knob  110  of which is shown in  FIG.  2   ) is couplable to the slide assembly  112  to drive movement of the slide assembly  112  by rotation of the knob assembly  106 . More specifically, the slide assembly  112  includes a threaded shaft  114  and a slider  116  that is received on the threaded shaft  114  and is translatable along the threaded shaft  114 . When the knob assembly  106  is coupled to the slide assembly  112 , rotation of the knob assembly  106  causes rotation of the threaded shaft  114 . Rotation of the threaded shaft  114  causes translation of the slider  116  along the threaded shaft  114 . A control wire  118  is in turn coupled between the slider  116  of the slide assembly  112  and the tool  104  (shown in  FIG.  1   ). Movement of the slide assembly  112 —i.e. translation of the slider  116  caused by rotation of the threaded shaft  114 —causes tensioning of the control wire  118 , and tensioning of the control wire  118  causes deflection of the tool  104 . As mentioned above, details of the slider  116  and control wire  118 , and the connection between the slider  116 , control wire  118  and tool  104  are disclosed in U.S. Pat. No. 10,661,057 (Davies et al.), and are not repeated herein. 
     Referring to  FIGS.  3  to  5   , a slip clutch assembly  120  is between the knob assembly  106  (only the inner knob  110  of which is shown in  FIGS.  3  to  5   ) and the slide assembly  112 . As shown in  FIG.  3   , when torque applied to the knob assembly  106  is below a threshold value (e.g. when the control wire  118 , not shown in  FIGS.  3  to  5   , is under a relatively low amount of tension, as would occur during routine use), the slip clutch assembly  120  couples the inner knob  110  of the knob assembly  106  to the slide assembly  112  to drive movement of the slide assembly  112  by rotation of the knob assembly  106 . As shown in  FIG.  4   , when torque applied to the knob assembly  106  is above a threshold value (e.g. when the control wire  118  is under relatively high tension and rotation of the knob assembly  106  is continued), the slip clutch assembly  120  decouples the inner knob  110  of the knob assembly  106  from the slide assembly  112  to prevent movement of the slide assembly  112  by rotation of the knob assembly  106 . This in turn prevents further tensioning of the control wire  118 , which in turn avoids or prevents or minimizes the risk of failure. As shown in  FIG.  5   , when the torque applied to knob assembly  106  is lowered to below threshold value, the slip clutch assembly  120  recouples the inner knob  110  of the knob assembly  106  to the slide assemblyl 12 , to again drive movement of the slide assembly  112  by rotation of the knob assembly  106 . 
     Referring to  FIG.  6   , in the example shown, the slip clutch assembly  120  includes a first disc  122 . The first disc  122  is fixed to the knob assembly  106  (only the inner knob  110  of which is shown in  FIG.  6   ) and is rotatable with the knob assembly  106 . More specifically, in the example shown, the first disc  122  is integral with the inner knob  110 . The first disc  122  has a first engagement face  124 —i.e. a face that has a feature (e.g. a mechanical features such as teeth, slots, and/or bumps, and/or a magnetic feature, and/or a frictional feature) that allows for the transmission of rotation to another element. In the example shown, the first engagement face  124  includes a first set of teeth. The slip clutch assembly  120  further includes a second disc  126 . The second disc  126  is mounted to the slide assembly  112  (as will be described in further detail below) to transmit rotation to the slide assembly  112 . The second disc  126  has a second engagement face  128 —i.e. a face that has a feature (e.g. a mechanical feature such as teeth, slots, and/or bumps, and/or a magnetic feature, and/or a frictional feature) that allows for the transmission of rotation from another element. In the example shown, the second engagement face  128  has a second set of teeth. The first engagement face  124  and second engagement face  128  face towards each other and the first set of teeth is engagable with the second set of teeth to lock the first disc  122  to the second disc  126  to drive rotation of the second disc  126  by rotation of the first disc  122  (as shown in  FIG.  3   ). Furthermore, the first set of teeth and the second set of teeth each have inclined side surfaces to facilitate disengagement of the first set of teeth and second set of teeth by rotation of the first disc  122 , as will be described below. 
     Referring back to  FIGS.  3  to  5   , the second disc  126  is translatable with respect to the slide assembly  112 , between a first position (shown in  FIGS.  3  and  5   ), and a second position (shown in  FIG.  4   ). In the first position, the second disc  126  is moved towards the first disc  122  and into toothed engagement with the first disc  122 , to couple the first disc  122  to the second disc  126  and thereby couple the knob assembly  106  to the slide assembly  112 . In in the second position, the second disc  126  is moved away from the first disc  122  and out of toothed engagement with the first disc  122 , to disengage the first disc  122  and the second disc  126  and thereby decouple the knob assembly from the slide assembly  112 . 
     Referring back to  FIG.  6   , in the example shown, in order to allow for translation of the second disc  126  with respect to the slide assembly  112  and allow for rotation of the second disc  126  to be transmitted to the slide assembly  112 , the slip clutch assembly further includes a driveshaft  130  fixed to the threaded shaft  114  of the slide assembly  112  and extending towards the knob assembly  106 . The driveshaft  130  includes a plurality of splines  132 . Referring also to  FIG.  7   , the second disc  126  is annular and includes an inner surface that has a plurality of longitudinal grooves  134  (only two of which are labelled). The second disc  126  is received on the driveshaft  130  with the splines  132  engaged with the grooves  134 . In order to move between the first position and the second position, the second disc  126  slides along the driveshaft  132 . Furthermore, due to the engagement of the splines  132  and the grooves  134 , rotation of the second disc  126  causes rotation of the threaded shaft  114 . 
     Referring still to  FIG.  6   , in the example shown, the slip clutch assembly  120  further includes a biasing member in the form of a spring  136 , more specifically a compression spring. The spring  136  biases the second disc  126  towards the first position, while allowing movement of the second disc  126  to the second position. In the example shown, the slip clutch assembly  120  includes a flange  138  from which the driveshaft  130  extends, and the spring  136  is received on the driveshaft  130  between the flange  138  and the second disc  126 , so that it is compressed between the flange  138  and the second disc  126 . 
     Referring back to  FIG.  3    in use, the spring  136  forces the second disc  126  to the first position, so that the second engagement face  128  (shown in  FIG.  6   ) is maintained in engagement with the first engagement face  124  (shown in  FIG.  6   ). This engagement couples the knob assembly  106  to the slide assembly  112 . If torque is applied to the knob assembly  106  to rotate the knob assembly  106 , the rotation of the knob assembly  106  will be transmitted to the slide assembly  112  via the slip clutch assembly  120 , to cause rotation of the threaded shaft  114 . That is, rotation of the knob assembly  106  will be transmitted to the first disc  122 , rotation of the first disc  112  will be transmitted to the second disc  126 , rotation of the second disc  126  will be transmitted to the driveshaft  130 , and rotation of the driveshaft  130  will be transmitted to the threaded shaft  114  of the slide assembly  112 . This in turn will cause translation of the slider  116 , tensioning of the control wire  118 , and deflection of the tool  104  (not shown in  FIG.  3   ). 
     Referring next to  FIG.  4   , if tension on the control wire  118  (not shown in  FIG.  4   ) increases (as might occur if, for example, a stiff secondary tool is within the tool  104  or if the tool  104  is in contact with patient anatomy) and the torque applied to the knob assembly  106  is increased to above a threshold value (as might occur if, for example, a user attempts to force the rotation of the knob assembly  106  despite the tension on the control wire  118 ), the knob assembly  106  will decouple from the slide assembly  112 , via the slip clutch assembly  120 . More specifically, torque applied to the knob assembly  106  will cause rotation of the first disc  122 ; however, due to the tension on the control wire  118 , the threaded shaft  114  will resist rotation. Due to the inclined side surfaces of the first and second sets of teeth, rotation of the first disc  122  will cause movement the second disc  126  away from the first disc  122 —i.e. the second disc  126  will compress the spring  136  and translate along the driveshaft  130 , to disengage the first engagement face  124  (shown in  FIG.  6   ) and the second engagement face  128  (shown in  FIG.  6   ). 
     Referring next to  FIG.  5   , if tension on the control wire  118  (not shown in  FIG.  5   ) decreases (as might occur if, for example, the stiff secondary tool is removed from within the tool  104 ) and the torque applied to the knob assembly  106  is decreased to below the threshold value, the knob assembly  106  will recouple to the slide assembly  112  via the slip clutch assembly  120 . More specifically, the spring  136  will bias the second disc  126  towards the first disc  122  and back to the first position, to re-engage the first engagement face  124  (shown in  FIG.  6   ) and the second engagement face  128  (shown in  FIG.  6   ). When the second disc  126  is back in the first position, rotation of the knob assembly  106  will be transmitted to the first disc  122 , rotation of the first disc  122  will be transmitted to the second disc  126 , rotation of the second disc  126  will be transmitted to the driveshaft  130 , and rotation of the driveshaft  130  will be transmitted to the threaded shaft  114  of the slide assembly  112 . This in turn will cause translation of the slider  116 , tensioning of the control wire  118 , and deflection of the tool  104  (not shown in  FIG.  5   ). 
     In the above examples, the slip clutch assembly  120  may optionally provide tactile and/or auditory feedback to a user, to indicate to the user that the control wire  118  is under tension. For example, as the second disc  126  moves to the second position, the user may feel a change in the resistance to rotation of the knob assembly  106 . Alternatively or in addition, an audible or tactile click may be felt when the second disc  126  moves back to the first position. Alternatively or in addition, the handle  102  may be provided with a visual indicator (e.g. a window that allows the user to see disengagement of the first disc  122  and the second disc  126 ) to indicate to the user that the control wire  118  is under tension. 
     In alternative examples, rather than providing only binary coupling and decoupling of the knob assembly  106  and the slide assembly  112 , the slip clutch assembly  120  can be configured to provide intermediate levels of coupling. For example, the teeth geometry and spring can be selected so that for a range of torques applied to the knob assembly  106 , the slip clutch assembly  120  transmits some rotation before decoupling the knob assembly  106  and the slide assembly  112 . This can serve as an alerting system, to alert the user that the torque is approaching the threshold value. 
     In alternative examples, rather than or in addition to being used to control tension on the control wire  118 , the slip clutch assembly  120  can be used to limit the amount of deflection that the user can impart to the tool  104 . 
     In alternative examples, the slip clutch assembly  120  may be configured so that the first disc  122  is movable towards and away from the knob assembly  106 , and the second disc  126  is translationally fixed. That is, either the first disc  122  or the second disc  126  may be translatable between a first position and a second position. 
     In alternative examples, rather than relying on mechanical engagement of the first engagement face and the second engagement face (e.g. engagement using teeth), the first engagement face and second engagement face can be magnetically attracted to each other in order to transmit rotation from the first disc to the second disc. The magnets can be selected such that when the torque is below the threshold value, the second disc rotates with the first disc due to magnetic attraction; however, when the torque is above the threshold value, the first disc rotates without transmitting rotation to the second disc. Alternatively, the first engagement face and second engagement face can rely on frictional forces between the two faces in order to transmit rotation from the first disc to the second disc. In such examples, a biasing member can be omitted, and the second disc can be longitudinally fixed with respect to the driveshaft and with respect to the first disc. 
     In any of the above examples, a lubricant may be provided to facilitate movement of the various parts. 
     The term ‘disc’ is used herein for simplicity, and is not limited to any particular shape. That is, a disc may be circular or another shape. 
     While the above description provides examples of one or more processes or apparatuses or compositions, it will be appreciated that other processes or apparatuses or compositions may be within the scope of the accompanying claims. 
     To the extent any amendments, characterizations, or other assertions previously made (in this or in any related patent applications or patents, including any parent, sibling, or child) with respect to any art, prior or otherwise, could be construed as a disclaimer of any subject matter supported by the present disclosure of this application, Applicant hereby rescinds and retracts such disclaimer. Applicant also respectfully submits that any prior art previously considered in any related patent applications or patents, including any parent, sibling, or child, may need to be re-visited.