Enhanced flexibility surgical stent

• US 5,843,175 A
• Filed: 06/13/1997
• Issued: 12/01/1998
• Est. Priority Date: 06/13/1997
• Status: Expired due to Term

• Current Assignee: Cook Medical Incorporated (Cook Group Incorporated)
• Original Assignee: Global Therapeutics, Inc. (Cook Group Incorporated)
• Inventors: Frantzen, John J.
• Primary Examiner(s): Yu, Mickey
• Assistant Examiner(s): Black, John M.
• Application Number:
  US08/874,975
• Time in Patent Office: 536 Days
• Field of Search: 623/1, 623/12, 606/192, 606/194, 606/195, 606/198
• US Class Current: 623/1.15
• CPC Class Codes: A61F 2/91 made from perforated sheet material or tubes, e.g. perforated by laser cuts or etched holes
• CPC Class Codes: A61F 2/915 with bands having a meander structure, adjacent bands being connected to each other
• CPC Class Codes: A61F 2002/91541 Adjacent bands are arranged out of phase
• CPC Class Codes: A61F 2002/91558 connected peak to peak
• CPC Class Codes: A61F 2002/91566 connected trough to trough
• CPC Class Codes: A61F 2230/0013 Horseshoe-shaped, e.g. crescent-shaped, C-shaped, U-shaped
• CPC Class Codes: A61F 2230/0054 V-shaped

Abstract

A surgical stent (10) is provided which can be radially expanded away from a central axis (2) within a body lumen, such as an artery. The stent (10) is formed from a series of struts (20) circumscribing a cylindrical contour of the stent (10). Each strut (20) has a series of bends (30) formed therein with each bend including at least one trough (32) and at least one crest (36). Gaps (40) are provided between adjacent struts (20). Each gap (40) is spanned by an axial element such as a tie bar (50) or links (180). Each tie bar (50) attaches to adjacent struts (20) through troughs (32) so that when the stent (10) is radially expanded, the struts (20) are not drawn together, but rather maintain their position and the stent (10) hence maintains its axial length without contracting. Other elements such as the links (180) can be provided spanning the gaps (140) to provide enhanced flexibility for the surgical stent (110) including such links (180).

Claims

1. An enhanced flexibility radially expandable substantially non-axially contracting surgical stent for implantation into a body lumen, such as an artery, said stent having a generally cylindrical contour both before and after radial expansion thereof, said stent comprising in combination:

at least three circumferential elements, each circumferential element forming an elongate circuit completely circumscribing said cylindrical contour;

each said circumferential element having a wave-like series of bends therein as each said circumferential element circumscribes said cylindrical contour of said stent;

each said wave-like series of bends including a trough and a crest, said trough defining a portion of said circumferential element where said circumferential element is more distant from adjacent said circumferential elements than other portions of said circumferential element, said crest defining a portion of said circumferential element where said circumferential element is closer to adjacent circumferential elements than other portions of said circumferential element;

at least two gaps circumscribing said cylindrical contour of said stent between said at least three circumferential elements;

each one of said gaps having at least one axial element having two extremities and located spanning said gap between a pair of adjacent circumferential elements, said extremities each attached to a different one of said pair of adjacent circumferential elements, joining said pair of circumferential elements together;

at least one of said gaps spanned only by axial elements having each one of said extremities attached to an adjacent one of said circumferential elements at one of said troughs;

at least one of said gaps spanned by at least one axial element having a means to elongate axially when forces applied to said stent cause a central axis of said stent to bend, such that portions of said gap can elongate axially allowing said stent to bend; and

wherein said gaps spanned only by axial elements having each said extremity attached at said troughs alternate with said gaps spanned by said axial elements having said means to elongate.

2. The enhanced flexibility stent of claim 1 wherein said axial elements which span said gaps with said extremities of said axial elements attached to said circumferential elements at said troughs are linear in form and aligned axially, parallel to said central axis of said stent.

3. The enhanced flexibility stent of claim 1 wherein said gaps include narrow gaps and wide gaps, said wide gaps having a greater width than said narrow gaps, said wide gaps alternating with said narrow gaps, said wide gaps having said axial elements having said means to elongate axially therein and said narrow gaps having said axial elements attached to said circumferential elements at said troughs therein.

4. An enhanced flexibility radially expandable substantially non-axially contracting surgical stent for implantation into a body lumen, such as an artery, said stent having a generally cylindrical contour both before and after radial expansion thereof, said stent comprising in combination:

at least three circumferential elements, each circumferential element forming an elongate circuit completely circumscribing said cylindrical contour;

each said circumferential element having a wave-like series of bends therein as each said circumferential element circumscribes said cylindrical contour of said stent;

each said wave-like series of bends including a trough and a crest, said trough defining a portion of said circumferential element where said circumferential element is more distant from adjacent said circumferential elements than other portions of said circumferential element, said crest defining a portion of said circumferential element where said circumferential element is closer to adjacent circumferential elements than other portions of said circumferential element;

at least two gaps circumscribing said cylindrical contour of said stent between said at least three circumferential elements;

each one of said gaps having at least one axial element having two extremities and located spanning said gap between a pair of adjacent circumferential elements, said extremities each attached to a different one of said pair of adjacent circumferential elements, joining said pair of circumferential elements together;

at least one of said gaps spanned only by axial elements having each one of said extremities attached to an adjacent one of said circumferential elements at one of said troughs;

at least one of said gaps spanned by at least one axial element having a means to elongate axially when forces applied to said stent cause a central axis of said stent to bend, such that portions of said gap can elongate axially allowing said stent to bend;

wherein said means to expand includes said axial element having a left arm attached to one of said circumferential elements at a left end and a right arm attached at a right end to an adjacent one of said circumferential elements, and an elbow attaching said left arm to said right arm, said elbow including means to flex; and

wherein said left arm and said right arm are oriented non-parallel to each other and wherein said elbow is attached to said left arm at an end of said left arm opposite said left end, and said elbow attached to said right arm at an end of said right arm opposite said right end.

5. The enhanced flexibility stent of claim 4 wherein said means to flex of said elbow includes said elbow formed from a common material with said left arm and said right arm and having a width less than a width of said left arm and said right arm.

6. The enhanced flexibility stent of claim 5 wherein said elbow includes a bight on an inner side of said elbow and at least one depression on an outer side of said elbow, said elbow having lesser thickness between said depression and said bight than a thickness of said left arm and said right arm.

7. The enhanced flexibility stent of claim 6 wherein said elbow includes at least two depressions including a left depression at an end elbow adjacent said left arm and a right depression in said elbow on a portion of said elbow adjacent said right arm, said left depression and said right depression spaced from said bight by a width less than a width of said left arm and said right arm.

8. A surgical stent for implantation into a body lumen, said stent having a substantially cylindrical contour and being radially expandable, the stent comprising in combination:

a plurality of circumferential elements, each circumferential element encircling said cylindrical contour of said stent;

at least two of said plurality of circumferential elements having an undulating form including at least one trough and at least one crest as said undulating circumferential elements circumscribe said cylindrical contour of said stent;

at least one axial element located between two adjacent said circumferential elements and attached to one of said adjacent circumferential elements at a first junction and to the other of said circumferential elements at a second junction;

said at least one axial element having a means to elongate axially such that a central axis of said stent is allowed to bend;

wherein said at least one axial element includes a left end adjacent said first junction and a right end adjacent said second junction, said left end including a left arm extending from said left end, said right end including a right arm extending from said right end, and said left arm and said right arm coupled together at a medially located elbow there between, said elbow having a means to flex, such that said left end can be moved away from said right end and said axial element elongates; and

wherein said left arm and said right arm extend linearly non-parallel to each other.

9. A surgical stent for implantation into a body lumen, said stent having a substantially cylindrical contour and being radially expandable, the stent comprising in combination:

a plurality of circumferential elements, each circumferential element encircling said cylindrical contour of said stent;

at least two of said plurality of circumferential elements having an undulating form including at least one trough and at least one crest as said undulating circumferential elements circumscribe said cylindrical contour of said stent;

at least one axial element located between two adjacent said circumferential elements and attached to one of said adjacent circumferential elements at a first junction and to the other of said circumferential elements at a second junction;

said at least one axial element having a means to elongate axially, such that a central axis of said stent is allowed to bend;

wherein said at least one axial element includes a left end adjacent said first junction and a right end adjacent said second junction, said left end including a left arm extending from said left end, said right end including a right arm extending from said right end, and said left arm and said right arm coupled together at an elbow there between, said elbow having a means to flex, such that said left end can be moved away from said right end and said axial element elongates; and

wherein said means to flex includes said elbow having a thickness which is less than a thickness of said left arm and said right arm, said elbow having a sufficiently narrow thickness to allow said elbow to bend, such that said left arm and said right arm can be flexed toward and away from each other with said left end and said right end being drawn closer to and further away from each other.

10. A radially expandable surgical stent having a generally cylindrical contour, comprising in combination:

a plurality of circumferential elements circumscribing the cylindrical contour of said stent, said circumferential elements including means to radially expand;

at least one axial element between each adjacent pair of said circumferential elements; and

at least one of said axial elements being an adjustable length axial element, said adjustable length axial element including;

a first arm attached to one circumferential element of the pair of circumferential elements at a first end;

a second arm attached to a second circumferential element of the pair of circumferential elements at a second end, said second arm not parallel with said first arm; and

a medially located elbow joining said first arm to said second arm, said elbow including means to flex causing said arms to pivot relative to each other and causing the pair of circumferential elements to move relative to each other.

11. The stent of claim 10 wherein said means to flex of said elbow includes said elbow having a lesser thickness than a thickness of said arms, such that said elbow exhibits a greater flexibility than said arms.