Micro-fabricated medical device having a non-helical cut arrangement
The present disclosure relates to interventional devices such as catheters and guidewire devices having micro-fabricated features for providing flexibility while maintaining good torquability. An interventional device includes an elongated member ( 500 ) having an arrangement of fenestrations which define a plurality of axially extending beams coupling a plurality of circumferentially extending rings. The fenestrations are arranged so that the resulting beams form a distributed, non-helical and non-linear pattern along the length of the elongated member. The pattern of fenestrations thereby minimizes or eliminates preferred bending axes.
1. An interventional device, comprising:
an elongated member having a wall and an interior lumen, the elongated member including a plurality of fenestrations extending through the wall and exposing the lumen, the plurality of fenestrations defining a plurality of axially extending beams and a plurality of circumferentially extending rings,
wherein the beams are arranged along a length of the elongated member to form a non-helical and non-linear pattern,
wherein at least a portion of the non-helical and non-linear pattern includes an imperfect ramp pattern such that no set of three successive segments or beam pairs within the imperfect ramp pattern are spaced according to the same rotational offset, and
wherein the imperfect ramp pattern includes an imperfect rotational offset from one beam pair to the next, the imperfect rotational offset being equal to a constant value plus or minus a variable modifying value.
2. The device of claim 1 , wherein the interventional device is a micro-catheter device.
3. The device of claim 1 , wherein the interventional device is a guidewire, wherein the guidewire includes a core, and wherein the elongated member is formed as a tube structure coupled to the core such that a distal section of the core passes into at least a portion of the tube structure.
4. The device of claim 3 , further comprising one or more coils disposed within the tube structure so as to be positioned between an outer surface of the distal section of the core and an inner surface of the tube structure.
5. The device of claim 1 , wherein the non-helical and non-linear pattern includes a distributed pattern, the distributed pattern including a first beam pair of the elongated member defined as being positioned at a zero degree position, wherein successive beam pairs are rotationally offset from the first beam pair to maximize the radial distribution of beam positions without surpassing a rotational offset limit, the rotational offset limit limiting the allowable rotation from one segment to the next.
6. The device of claim 5 , wherein the rotational offset limit restricts the rotational offset from one beam pair to the next to a value of about 60 to 120 degrees.
7. The device of claim 5 , wherein successive beam pairs are positioned near the midpoint of a largest remaining positional gap without surpassing the rotational offset limit.
8. The device of claim 7 , wherein the successive segments are positioned as close to the midpoint of a largest remaining positional gap as the rotational offset limit allows.
9. The device of claim 5 , wherein the distributed pattern has a positional granularity of about 0.1 to 30 degrees.
10. The device of claim 5 , wherein the rotational offset limit is greater than 30 degrees.
11. The device of claim 1 , wherein the variable modifying value ranges from 5 to 15 degrees.
12. The device of claim 1 , wherein the imperfect ramp pattern has a two-beam configuration, and wherein the constant value portion of the imperfect rotational offset is about 90 degrees.
13. The device of claim 1 , wherein at least a portion of the non-helical and non-linear pattern includes a sawtooth pattern that includes a rotational offset that periodically reverses direction such that no section wraps around the entire circumference of the elongated member before reversing direction.
14. The device of claim 13 , wherein the sawtooth pattern includes a first apex and a second apex, and wherein rotational offsets of the sawtooth pattern reverse direction upon reaching the first or second apex, and wherein the first and second apexes are separated by about 90 degrees.
15. An interventional device, comprising:
an elongated member having a wall and an interior lumen, the elongated member including a plurality of fenestrations extending through the wall and exposing the lumen, the plurality of fenestrations defining a plurality of axially extending beams and a plurality of circumferentially extending rings,
wherein the beams are arranged along a length of the elongated member to form a non-helical and non-linear pattern, and
wherein at least a portion of the non-helical and non-linear pattern includes a sawtooth pattern that includes a rotational offset that periodically reverses direction such that no section wraps around the entire circumference of the elongated member before reversing direction.
16. The device of claim 15 , wherein the sawtooth pattern includes a first apex and a second apex, and wherein rotational offsets of the sawtooth pattern reverse direction upon reaching the first or second apex, and wherein the first and second apexes are separated by about 90 degrees.
17. The device of claim 16 , wherein the first and second apexes are separated by about 90 degrees.
18. The device of claim 15 , wherein the interventional device is a micro-catheter device or a guidewire device.
19. The device of claim 18 , wherein the interventional device is a guidewire that includes a core, and wherein the elongated member is formed as a tube structure coupled to the core such that a distal section of the core passes into at least a portion of the tube structure.
20. The device of claim 19 , further comprising one or more coils disposed within the tube structure so as to be positioned between an outer surface of the distal section of the core and an inner surface of the tube structure.
21. The device of claim 19 , wherein the core is formed from stainless steel or nitinol.
22. The device of claim 19 , wherein the tube structure is formed from nitinol.
23. The device of claim 19 , wherein the fenestrations are arranged in a one-beam, two-beam cut, three-beam, or more than three-beam pattern.
24. The device of claim 19 , wherein the elongated member is formed from a succession of segments, each segment including a first pair of circumferentially opposed beams and a second pair of circumferentially opposed beams which are rotationally offset by about 90 degrees from the first pair of beams.