摘要:
An expandable structure comprising: a first shape memory (SM) portion which is in a strain-induced state; and a second portion which resists expansion of said structure due to said first portion, over a plurality of different expansion states of said first portion. Optionally, wherein said SM portion resists contraction of said structure due to forces applied by said second portion. Optionally or alternatively, said strain induced state is characterized by a SM portion expanding force decreasing as a function of strain of said SM portion, so as to have a difference of at least 10% in force between two strain states said structure is usable at.
摘要:
A method of loading a medical device into a delivery system includes providing a two-stage shape memory alloy at a temperature at which at least a portion of the alloy includes austenite. A stress which is sufficient to form R-phase from at least a portion of the austenite is applied to the medical device at the temperature. A delivery configuration of the medical device is obtained, and the medical device is loaded into a restraining member. Preferably, the delivery configuration of the medical device includes stress-induced R-phase.
摘要:
An implantable expandable medical device in which selected regions of the device are in a martensite phase and selected regions are in an austenite phase. The martensitic regions exhibit pseudoplastic behavior in vivo and may be deformed without recovery under in vivo body conditions. In contrast the austenitic regions exhibit superelastic behavior in vivo and will recover their pre-programmed configuration upon deformation or release of an applied strain.
摘要:
A process to load a medical device comprising a shape memory material into a delivery system is described herein. According to one aspect, the method includes applying a force to the medical device to obtain a delivery configuration thereof, where the device is at a first temperature within an R-phase temperature range of the shape memory material during application of the force. The medical device is cooled in the delivery configuration to a second temperature at or below a martensite finish temperature of the shape memory material. The force is then removed from the medical device, and the device is loaded into a delivery system. Preferably, the medical device substantially maintains the delivery configuration during the loading process.
摘要:
A method for arthroplasty includes using a self-locking prosthesis that has a member structured to transfer a load produced by the weight of a patient to a bone. An expandable bone-locking portion that is integral to the member includes a shape-memory material and expands to produce a locking force. A portion of the bone is removed to form an aperture in the bone. The bone-locking portion is inserted into the aperture, and a temperature increase causes a change from a contracted state to an expanded state resulting in expansion of the bone-locking portion so as to contact the inner surface. The expanding is sufficient to create a locking force at the junction between the inner surface and the bone-locking portion of the prosthesis and the majority of the locking force is applied at or above the metaphysis. The length/width ration of the prosthesis may be less than or equal to 5. The resulting reconstructed long-bone may have improved primary and long-term stability.
摘要:
Generally, the present disclosure includes a hybrid segmented endoprosthesis for delivery into a lumen of a body. The hybrid segmented endoprosthesis has different types of segments that are joined together. The segments are typically distinct and distinguishable from each other by each segment having a unique configuration different from at least one other segment. Additionally, the segments can be coupled together by various processes well known for interconnecting the materials of endoprostheses. The segmented endoprosthesis can provide improved deliverability, strength, flexibility, and/or functionality during and after deployment. The use of a segmented endoprosthesis can combine the configurations of multiple small endoprostheses into a standard- or regular-sized endoprosthesis.
摘要:
An intravascular stent especially suited for implanting in curved arterial portions or ostial regions. The stent can include an end region which is fabricated to have a greater radial strength than the remaining axial length of the stent. Such a stent is particularly suited for use in ostial regions, which require greater support near the end of the stent. The stent alternatively can include sections adjacent the end of the stent with greater bending flexibility than the remaining axial length of the stent. Such a stent is particularly suited for use in curved arteries. The stent can also be constructed with an end that has greater radial strength and sections adjacent the end with greater bending flexibility. Such a stent prevents flaring of the stent end during insertion.
摘要:
Methods of selectively treating linear elastic materials to produce localized areas of superelasticity and/or shape-memory are disclosed. In an illustrative method, a linear elastic workpiece may be formed into a particular shape by cold-forming or other low-temperature process, and incorporated into a medical device such as an embolic protection filter, vena cava filter, stent or guidewire. A heat source may be used to apply thermal energy to selective areas of the workpiece, imparting superelasticity to the material.
摘要:
An implantable coil stent comprises at least a first curved segment and a second curved segment which arc about the longitudinal axis of the stent. An expandable link extends between the second end of the first curved segment and the first end of the second curved segment.