Patent Publication Number: US-2023144490-A1

Title: Laser cut hypotube patterns

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority to U.S. Provisional Patent Application No. 63/276,510, filed Nov. 5, 2021, the entire disclosure of which is incorporated by reference herein. 
    
    
     FIELD 
     The present invention relates to a biocompatible flexible tubular medical device for insertion into the body during medical procedures, and more specifically, a hypotube portion of the medical device providing flexibility and pushability for access into that anatomy and to navigate the human vasculatures. 
     BACKGROUND 
     Guidewires are the workhorse in the medical device. Guidewires are relatively thin and flexible devices used in the medical field for numerous applications. In interventional operations, one or two guidewires may be used to complete the procedure. The guidewire should provide torsional rigidity while retaining a satisfactory flexibility and stiffness without kinking. These features will allow the guidewire to be manipulated to go through small body vessels and cavities. The outside diameter of the guide wire guidewire is usually small so that it will fit inside of the lumen of the catheter. 
     In order to obtain maximum performance and patient safety, it is important that the guidewire be as small in diameter as possible, particularly in the tip region (but not so small as to create a danger of the tip breaking loose in the body); that the distal tip region be highly flexible to permit negotiation of difficult turns within the body; that the guidewire also be stiff enough axially to be advanced by pressure from the proximal end outside the body; and that the guidewire have good steerability or torque response, i.e., the tip to handle turn ratio should be as close to 1:1 as possible, without whipping. Most prior art guidewires offer or comprise of these desired features, e.g., trading tip flexibility for good torque response. Some prior art guidewires use spiral cut hypotube. One of the drawbacks with this design is that when the guidewire is rotated, the spiral cut hypotube, may wind and/or unwind the individual turnings that may impact flexibility and/or pushability of the guidewire. 
     Accordingly, there is a need for systems and methods that provide solutions. The present invention is directed toward systems and methods for solving these problems. 
     SUMMARY 
     The present invention pertains to an improved laser cut hypotube that provides advantages in flexibility for a medical device. After the laser cut wave pattern is cut, it can fabricate into a guidewire or/and can make as a pusher for anything that required push and pull in the anatomy vasculature (such as an embolic coils pusher, stent retriever pusher . . . etc.). 
     One embodiment of the present invention is used in a medical device, such as a guidewire or catheter, that includes a flexible hypotube portion having a laser cut pattern of wave cuts designed to provide flexibility to the hypotube. 
     Another embodiment of the present invention includes a hypotube having wave cuts with different pitches to change the flexibility of the hypotube from a distal end to a proximal end. 
     Another embodiment of the present invention includes a hypotube having wave cuts with different angles and/or pitches to change the flexibility of the hypotube from a distal end to a proximal end. 
     The laser cut wave pattern provides the medical device with the best flexibility while maintaining pushability further into the most tortuous vasculature. Most of all, ability to torque the medical device back and forth, theoretically 1 to 1 response, without stretching the flexible hypotube. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    shows a flexible hypotube having wave cuts designed to provide flexibility while maintaining pushability into the most tortuous vasculature. 
         FIG.  2    shows one example of three different wave pitch segments for use with the flexible hypotube. 
         FIG.  3    shows the flexible hypotube having wave cuts in different directions or angles. 
         FIGS.  4 A- 4 D  show examples of a continuous wave cut in different directions. 
         FIGS.  5 A- 5 D  show examples of a non-continuous wave cuts in different directions. 
         FIG.  6    shows one embodiment of the distal segment with distal wave cuts. 
         FIG.  7    shows one embodiment of the middle segment with middle wave cuts. 
         FIG.  8    shows one embodiment of the proximal segment with proximal wave cuts. 
         FIG.  9    shows one embodiment of a distal segment with distal wave cuts, which is similar to  FIG.  6   , without the transition wave cut. 
         FIG.  10    shows one embodiment of a middle segment with middle wave cuts, which is similar to  FIG.  7   , without the transition wave cut. 
         FIG.  11    shows one embodiment of a proximal segment with proximal wave  275 , which is similar to  FIG.  8   , without the transition wave cut. 
         FIGS.  12 A- 12 C  show one embodiment of a guide wire assembly using a flexible hypotube that includes one or more areas of flexibility with multiple wave cut patterns. 
         FIGS.  13 A- 13 C  show one example of a stent delivery system with a flexible hypotube that includes one or more areas of flexibility with multiple wave cut patterns. 
     
    
    
     DETAILED DESCRIPTION 
     The present invention describes systems and methods for a flexible hypotube for use in a medical device having wave cuts designed to provide flexibility while maintaining pushability for the medical device to advance further into the most tortuous vasculature. 
     The laser cut hypotube/pusher can be used as the primary pusher in delivering other neurovascular device like the delivery of a stent. 
       FIG.  1    shows a flexible hypotube  100  having wave cuts designed to provide flexibility while maintaining pushability into the most tortuous vasculature. The flexibility of the flexible hypotube  100  depends on the wave cuts and the pitch of the wave cuts. A smaller wave cut pitch is more flexible than a larger wave cut pitch. This allows the selection of different wave cut pitches to change the flexibility along the length of the flexible hypotube  100 . Typically, the distal end of the flexible hypotube should be the most flexible and the proximal end the least flexible. This may be done by changing the push ability pitch distance between adjacent wave cuts so the distal end has wave cuts with a smaller pitch and the pitch becomes larger or further apart from distal end toward the proximal end of the flexible hypotube  100 . The wave cuts are designed to wrap around the hypotube and vary in pitch and direction between sets of wave cuts. The wave cut design also provides the ability to torque the flexible hypotube back and forth, with a 1 to 1 response, without stretching, winding or unwinding, the flexible hypotube. 
     The flexible hypotube includes an elongated body having a laser cut pattern of wave cuts. In some embodiments the elongated body may be formed of a metallic material such as stainless steel or a Nitinol material or other suitable metallic material. In some embodiments, the elongated body may be formed of a polymer material. In some embodiments, the elongated body may be made of both a metallic material and polymer material. 
     The flexible hypotube elongated body may be formed in any desired length and thickness. The wave cuts of the flexible hypotube may be formed using a suitable manufacturing process, such as a laser cut or a saw cut. Additional suitable techniques include chemical etching and abrasive grinding. 
     In the embodiment shown, the flexible hypotube  100  includes three wave cut segments: a distal segment  105 , a middle segment  110 , and a proximal segment  115 . In some embodiments, the three wave cut segments may include wave cuts having the same flexibility for each segment, so the flexibility of the flexible hypotube  100  is constant in the wave cut area. In some embodiments the three wave cut segments have a different flexibility for each segment, so the flexibility of each segment varies in the wave cut area. The individual wave cuts within each three wave cut segments may vary in distance between wave cuts (pitch) and/or direction of the wave cut (angle), with some wave cuts angled to the right (proximally) or angled to the left (distally). The flexibility of the hypotube  100  depends on the pitch of the wave cut and the number of wave cuts in each direction. 
       FIG.  2    shows one example of three different wave pitch segments for use with the flexible hypotube  100 . Each wave pitch segment includes a different wave cut pitch that is used to vary the flexibility of the flexible hypotube  100 . The wave pitch segments include a distant pitch segment  120  with a distant wave cut pitch  125 , a middle pitch segment  130  with a middle wave cut pitch  135 , and a proximal pitch segment  140  with a proximal wave cut pitch  145 . In the example shown, the distal wave cut pitch  125  may be 1.24 mm, the middle wave cut pitch  135  may be 1.50 mm, and the proximal wave cut pitch  145  may be 2.50 mm. In other embodiments, the wave cut pitch may be more or less than the example shown. The example in the figures shows three wave cut pitches  125 ,  135 ,  145 , but there could be more or less than three wave cut pitches. Each of the wave pitch segments also has a wave pitch segment length, including a distal wave pitch segment length  150 , a middle wave pitch segment length  155  and a proximal wave pitch segment length  160 . In the example shown, the distal wave pitch segment length is 7 cm, the middle wave pitch segment length  155  is 7 cm, and the proximal wave pitch segment length  160  is 10 cm. In other embodiments, the wave pitch segment length may be more or less than the example shown. 
       FIG.  3    shows the flexible hypotube  100  having wave cut sets in different directions or angles. In some embodiments, there are wave cuts angled to the right, or proximally, and wave cuts angled to the left, or distally. The left and right wave cuts may be cut spirally around the flexible hypotube  100  with the desired wave cut pitch for the desired flexibility. 
       FIGS.  4 A- 5 D  show examples of a continuous wave cut in different directions that may be used in the distal segment  105 , the middle segment  110 , and the proximal segment  115 . In some embodiments, there is an equal number of right wave cuts R angled to the right (proximally) and left wave cuts L angled to the left (distally), while in other embodiments have a different number of right wave cuts R and left wave cuts L. There is also a transition wave cut T connecting the right wave cuts R and left wave cuts L. 
       FIG.  4 A  shows an example of wave cuts that include two right wave cuts  2 R, two left wave cuts  2 L, and a transition wave cut T connecting the two right wave cuts  2 R and two left wave cuts  2 L. The wave cut is a continuous wave cut from the distal end to the proximal end. 
       FIG.  4 B  shows an example of continuous wave cuts having a different of wave cuts in each direction that includes two right wave cuts  2 R, three left wave cuts  3 L, and a transition wave cut T connecting the two right wave cuts  2 R and three left wave cuts  3 L. 
       FIG.  4 C  shows an example of wave cuts that include three right wave cuts  3 R, three left wave cuts  3 L, and a transition wave cut T connecting the three right wave cuts  3 R and three left wave cuts  3 L. 
       FIG.  4 D  shows an example of wave cuts that include four right wave cuts  4 R, four left wave cuts  4 L, and a transition wave cut T connecting the four right wave cuts  4 R and four left wave cuts  4 L. 
       FIGS.  6 A- 6 D  show examples of a non-continuous wave cuts in different directions that may be used in the distal segment  105 , the middle segment  110 , and the proximal segment  115 . In some embodiments, there is an equal number of right wave cuts R angled to the right (proximally) and left wave cuts L angled to the left (distally), while in other embodiments have a different number of right wave cuts R and left wave cuts L. The right wave cuts R and left wave cuts L are not connected and are separated by an uncut part X. 
       FIG.  6 A  shows an example of two right wave cuts  2 R and two left wave cuts  2 L separated by uncut part X. 
       FIG.  6 B  shows an example of three right wave cuts  3 R and three left wave cuts  3 L separated by uncut part X. 
       FIG.  6 C  shows an example of wave cuts that include four right wave cuts  4 R and four left wave cuts  4 L separated by uncut part X. 
       FIG.  6 D  shows an example of different of wave cuts in each direction that includes three right wave cuts  3 R and four left wave cuts  4 L separated by uncut part X. 
     In some embodiments, the wave cuts are one continuous wave cut from the distal end to the proximal end, with the right and left wave cuts connected with transition wave cuts (see  FIGS.  7 - 9   ), while in other embodiments the wave cuts may not be connected, with an uncut section between the left and right wave cuts (see  FIGS.  10 - 12   ). 
       FIG.  6    shows one embodiment of the distal segment  105  with distal wave cuts  165 . The distal wave cuts  165  include a right distal wave cut  165   a , a left distal wave cut  165   b , and a transition distal wave cut  165   c  between the right and left distal wave cuts  165   a ,  165   b . The right and left distal wave cuts  165   a ,  165   b  are separated by distal wave cut pitch  125 . 
       FIG.  7    shows one embodiment of the middle segment  110  with middle wave cuts  170 . The middle wave cuts  170  include a right middle wave cut  170   a , a left middle wave cut  170   b , and a transition middle wave cut  170   c  between the right and left middle wave cuts  170   a ,  170   b . The right and left middle wave cuts  170   a ,  170   b  are separated by middle wave cut pitch  135 . 
       FIG.  8    shows one embodiment of the proximal segment  115  with proximal wave cuts  175 . The proximal wave cuts  175  include a right proximal wave cut  175   a , a left proximal wave cut  175   b , and a transition proximal wave cut  175   c  between the right and left proximal wave cuts  175   a ,  175   b . The proximal wave cuts  175  are separated by proximal wave cut pitch  145 . 
       FIG.  9    shows one embodiment of a distal segment  205  with distal wave cuts  265 , which is similar to distal segment  105  without the transition wave cut  165   c . The distal wave cuts  265  includes a right distal wave cut  265   a  and a left distal wave cut  265   b  separated by an uncut section  265   d  between the right and left distal wave cuts  265   a ,  265   b . The distal wave cuts  265  are separated by distal wave cut pitch  125 . 
       FIG.  10    shows one embodiment of a middle segment  210  with middle wave cuts  270 , which is similar to middle segment  110  without the transition wave cut  170   c . The middle wave cuts  270  includes a right middle wave cut  270   a  and a left middle wave cut  270   b  separated by an uncut section  270   d  between the right and left distal wave cuts  270   a ,  270   b . The middle wave cuts  270  are separated by middle wave cut pitch  135 . 
       FIG.  11    shows one embodiment of a proximal segment  215  with proximal wave cuts  275 , which is similar to distal segment  115  without the transition wave cut  175   c . The proximal wave cuts  275  includes a right proximal wave cut  275   a  and a left proximal wave cut  275   b  separated by an uncut section  265   d  between the right and left proximal wave cuts  275   a ,  275   b . The middle wave cuts  275  are separated by middle wave cut pitch  145 . 
     The flexible hypotube  100  may be made using hypotubes of various lengths and thicknesses depending on the desired flexible properties for the particular device. For example, thinner thicknesses for the hypotube would be used for increased flexibility, while thicker thicknesses would be used for increased pushability. In some embodiments, the hypotube may have variable thickness, with a thinner distal end for flexibility and a thicker proximal end for pushability. 
     Guidewire Assembly 
       FIGS.  12 A- 12 C  show one embodiment of a guide wire assembly  300  having a flexible core wire  305  with an enlarged distal end  310  covered by a flexible hypotube  315 . The flexible hypotube  315  includes multiple areas of flexibility with multiple cut patterns, including a distal flexible segment  320  having wave cuts with a tight pitch and high amplitude, and a stiffer transition segment  325 , and an uncut portion  330  of the hypotube having no wave cuts. The flexible hypotube  315  may be similar to flexible hypotube  100  described above. 
     The distal flexible segment  320  may include a distal segment  335 , similar to the distal segment  105  (see  FIG.  6   ), and a middle segment  340 , similar to the middle segment  110  (see  FIG.  7   ). The transition segment  325  is similar to the proximal segment  115  (see  FIG.  8   ). 
     The distal segment  335  include distal wave cuts  365 . The distal wave cuts  365  include two right distal wave cuts  365   a , two left distal wave cuts  365   b , and a transition distal wave cut  365   c  between the right and left distal wave cuts  365   a ,  365   b . In other embodiments, there may be more or less left and right distal wave cuts  365   a ,  365   b  (see  FIGS.  5 A- 5 D ). 
     The middle segment  340  include middle wave cuts  370 . The middle wave cuts  370  include two right middle wave cuts  370   a , two left middle wave cuts  370   b , and a transition middle wave cut  370   c  between the right and left middle wave cuts  370   a ,  370   b . In other embodiments, there may be more or less left and right middle wave cuts  370   a ,  370   b  (see  FIGS.  5 A- 5 D ). 
     The proximal segment  345  include proximal wave cuts  375 . The proximal wave cuts  375  include two right proximal wave cuts  375   a , two left proximal wave cuts  375   b , and a transition proximal wave cut  375   c  between the right and left proximal wave cuts  375   a ,  375   b . In other embodiments, there may be more or less left and right proximal wave cuts  375   a ,  375   b  (see  FIGS.  5 A- 5 D ). 
     Stent Delivery System 
       FIGS.  13 A- 13 C  show one example of a stent delivery system  400  with a flexible hypotube  405  that includes one or more areas of flexibility with multiple wave cut patterns. The stent delivery system  400  also includes a flexible core wire  410  with an enlarged distal end  415 , a flexible distal coil  420 , a device allocation slot  425 , a device dislodgment mechanism  430  and a pusher coil  435 . 
     The flexible distal coil  420  is positioned over the flexible core wire  410  and pushed distally to engage the enlarged distal end  415 . The flexible core wire  410  may be made of a suitable core wire material, such as Nitinol, and the flexible distal coil  420  may be made of a suitable coil material, such as platinum/iridium (PT/IR). 
     The device allocation slot  425  is an open area of the flexible core wire  410  between the flexible distal coil  420  and the device dislodgment mechanism  430 . A stent is positioned within the device dislodgment mechanism  430 . Once the stent delivery system  400  is in the desired position within the anatomy, the device dislodgment mechanism  430  is configured to deliver the stent distally to the device allocation slot  425  for expansion of the stent. 
     The pusher coil  435  is positioned between the device dislodgment mechanism  430  and the flexible hypotube  405 . The pusher coil  435  may be made of stainless steel. 
     The flexible hypotube  405  may include one or more wave cut segments. In the example shown, the wave cut segments include a distal segment  440 , a middle segment  445 , and a proximal segment  450 . The flexible hypotube  405  also includes a proximal segment  455  that is uncut. The flexible hypotube  405  may be any of the flexible hypotubes described herein. 
     Example embodiments of the methods and systems of the present invention have been described herein. As noted elsewhere, these example embodiments have been described for illustrative purposes only and are not limiting. Other embodiments are possible and are covered by the invention. Such embodiments will be apparent to persons skilled in the relevant art(s) based on the teachings contained herein. Thus, the breadth and scope of the present invention should not be limited by any of the above-described exemplary embodiments but should be defined only in accordance with the following claims and their equivalents.