Medical device with slotted memory metal tube

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 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.

What is claimed is: 
     
         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, said memory metal tube having an expandable section that is substantially filled by an elastically deformable polymer, which upon expansion in a tubular cavity plugs the cavity; and   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.   
     
     
         2 . The instrument of  claim 1  being a retrieval basket for retrieving particles to be removed from the human body. 
     
     
         3 . The instrument of  claim 1  being a dilator to enlarge the diameter of collapsed or obstructed ducts, veins, arteries or other cavities in the human body. 
     
     
         4 . The instrument of  claim 1  being a reaming tool to cut parts off the wall of a cavity by rotational movement around the longitudinal axis of the instrument. 
     
     
         5 . The instrument of  claim 1  being an expansion tool that is expandable at a distal end to enlarge a body cavity. 
     
     
         6 . The instrument of  claim 1  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. 
     
     
         7 . The device of  claim 6  wherein the bending hooks close during retraction into the delivery tube to provide an internal gripping function. 
     
     
         8 . The device of  claim 6  wherein the bending hooks curl outside during advance from the delivery tube to provide an external gripping function. 
     
     
         9 . The device of  claim 8  wherein the hooks curl outside sufficiently to engage the outer wall of the memory metal tube to form closed loops. 
     
     
         10 . The instrument of  claim 1  wherein a wire, eyelet or hook is connected to the proximal end of the device to facilitate removal of the device. 
     
     
         11 . The instrument of  claim 1  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 filter. 
     
     
         12 . The instrument of  claim 1  further comprising optical measuring means. 
     
     
         13 . The instrument of  claim 1  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. 
     
     
         14 . The instrument of  claim 13  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. 
     
     
         15 . The instrument of  claim 8  wherein the steerable wire is hollow and contains an optical system to provide visual information about the condition and size of the cavity. 
     
     
         16 . The instrument of  claim 11  wherein the steerable wire is hollow and contains a laser system as the optical system to work with at the distal end. 
     
     
         17 . 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.