Medical instrument with slotted memory metal tube

• US 20050027245A1
• Filed: 08/23/2004
• Published: 02/03/2005
• Est. Priority Date: 02/23/1996
• Status: Active Grant

• Current Assignee: EVM Systems LLC (Acacia Research Corporation)
• Original Assignee: Memory Medical Systems, Inc.
• Inventors: Besselink, Petrus A., Sachdeva, Rohit C. L.
• Granted Patent: US 7,037,321 B2
• Time in Patent Office: Days
• US Class Current: 604/95.50
• CPC Class Codes: A61B 1/00082 Balloons
• CPC Class Codes: A61B 1/0058 using shape-memory elements
• CPC Class Codes: A61B 1/015 Control of fluid supply or evacuation
• CPC Class Codes: A61B 1/018 for receiving instruments
• CPC Class Codes: A61B 1/307 for the urinary organs, e.g. urethroscopes, cystoscopes
• CPC Class Codes: A61B 1/3137 for examination of the interior of blood vessels
• CPC Class Codes: A61B 17/122 Clamps or clips , e.g. for the umbilical cord for the vas deferens A61F6/206
• CPC Class Codes: A61B 17/1285 for minimally invasive surgery
• CPC Class Codes: A61B 17/221 Gripping devices in the form of loops or baskets for gripping calculi or similar types of obstructions surgical snare instruments A61B17/32056
• CPC Class Codes: A61B 17/32056 Surgical snare instruments for removing or smashing calculi A61B2017/2212; tonsillotomes A61B17/26
• CPC Class Codes: A61B 2017/00349 Needle-like instruments having hook or barb-like gripping means, e.g. for grasping suture or tissue A61B17/06066 takes precedence
• CPC Class Codes: A61B 2017/00867 shape memory effect
• CPC Class Codes: A61B 2017/00986 Malecots, e.g. slotted tubes, of which the distal end is pulled to deflect side struts
• CPC Class Codes: A61B 2017/2212 having a closed distal end, e.g. a loop
• CPC Class Codes: A61B 2017/2215 having an open distal end
• CPC Class Codes: A61B 2090/061 for measuring dimensions, e.g. length
• CPC Class Codes: A61B 2090/063 for measuring volume
• CPC Class Codes: A61B 5/0084 for introduction into the body, e.g. by catheters A61B5/1459 takes precedence
• CPC Class Codes: A61B 5/1076 for measuring dimensions inside body cavities, e.g. using catheters A61B3/1005 takes precedence
• CPC Class Codes: A61B 5/6853 with a balloon
• CPC Class Codes: A61F 2/82 : Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents stent-grafts for tubular structures of the body other than blood vessels A61F2/04; stent-grafts for blood vessels A61F2/07; instruments specially adapted for placement or removal of stents or stent-grafts A61F2/95; for closing wounds, or holding wounds closed A61B17/04 - A61B17/115; dilators A61M29/00
• CPC Class Codes: A61F 2002/30092 : using shape memory or superelastic materials, e.g. nitinol
• CPC Class Codes: A61F 2210/0023 : operated at different temperatures whilst inside or touching the human body, heated or cooled by external energy source or cold supply
• CPC Class Codes: A61M 2025/0057 : Catheters delivering medicament other than through a conventional lumen, e.g. porous walls or hydrogel coatings
• CPC Class Codes: A61M 25/0013 : Weakening parts of a catheter tubing, e.g. by making cuts in the tube or reducing thickness of a layer at one point to adjust the flexibility
• CPC Class Codes: A61M 25/0138 : having flexible regions as a result of weakened outer material, e.g. slots, slits, cuts, joints or coils
• CPC Class Codes: A61M 25/0158 : with magnetic or electrical means, e.g. by using piezo materials, electroactive polymers, magnetic materials or by heating of shape memory materials
• CPC Class Codes: A61M 25/04 : in the body, e.g. expansible A61M25/10, A61M16/0488 take precedence
• CPC Class Codes: A61M 25/09 : Guide wires
• CPC Class Codes: A61M 29/02 : Dilators made of swellable material balloon catheters for angioplasty A61M25/104

Abstract

A series of medical instruments can be made with the use of shape memory tube with a transformation temperature that is above or below the ambient temperature. In the first case, the material behaves with the shape memory effect and in the second case the behavior is superelastic. The wall of the tube has been provided with a plurality of slots in specific places, often near or at the distal end of the instrument, and in specific arrangements which allow local variations in diameter, shape, and/or length. These variations can either be caused by the memory effect during temperature change or by superelastic behavior during change of the mechanical influences on the memory metal by the surrounding material.

Claims

1. A medical instrument comprising at least one memory metal tube programmed for memory effect or superelasticity and having in at least one section thereof a plurality of slots such that the slotted section is capable of expansion and contraction.

2. The instrument of claim 1 further comprising a delivery tube that surrounds at least the slotted section of the memory metal tube during delivery and which is partially removed from surrounding the slotted section of the memory metal tube by a relative longitudinal movement between the respective tubes.

3. The instrument of claim 2 being a retrieval basket for retrieving particles to be removed from the human body.

4. The instrument of claim 2 being a dilator to enlarge the diameter of collapsed or obstructed ducts, veins, arteries or other cavities in the human body.

5. The instrument of claim 2 being a reaming tool to cut parts off the wall of a cavity by rotational movement around the longitudinal axis of the instrument.

6. The instrument of claim 2 being an expansion tool that is expandable at a distal end to enlarge a body cavity.

7. The instrument of claim 2 wherein the slots in the memory metal tube extend to the distal end of the tube and have been programmed to change into bending hooks upon delivery from the delivery tube.

8. The device of claim 7 wherein the bending hooks close during retraction into the delivery tube to provide an internal gripping function.

9. The device of claim 7 wherein the bending hooks curl outside during advance from the delivery tube to provide an external gripping function.

10. The device of claim 9 wherein the hooks curl outside sufficiently to engage the outer wall of the memory metal tube to form closed loops.

11. The instrument of claim 2 wherein said memory metal tube has an expandable section that is substantially filled by an elastically deformable polymer, which upon expansion in a tubular cavity plugs the cavity.

12. The instrument of claim 1I wherein a wire, eyelet or hook is connected to the proximal end of the device to facilitate removal of the device.

13. The instrument of claim 11 wherein the elastically deformable polymer is of the UV-curing type which enables the material to be cured by exposure to light emitted from an optical fiber.

14. The instrument of claim 2 having an expandable section that surrounds or is surrounded by an elastic material in the shape of a balloon connected at its proximal end and distal ends with one-way valves that only open in a distal direction such that intermittent relative axial movement of the delivery tube compared to the memory metal tube causes a pumping action in the distal direction.

15. The instrument of claim 2 further comprising optical measuring means.

16. The instrument of claim 2 further comprising a second delivery tube within the memory metal tube, and a steerable superelastic wire with a curved tip within said second delivery tube.

17. The instrument of claim 16 wherein said steerable wire is programmed to meet the wall of a cavity within which the instrument is placed to measure the radius of the cavity.

18. The instrument of claim 17 wherein the steerable wire is hollow and contains an optical system to provide visual information about the condition and size of the cavity.

19. The instrument of claim 18 wherein the steerable wire is hollow and contains a laser system as the optical system to work with at the distal end.

20. The instrument of claim 1 wherein the pattern of slots is provided such that heating at least one of the wall segments defined by the slot provides a contraction, expansion or bending of that segment which causes an angular deviation of the axis of top portion of the distal tip of the memory metal tube.