US5876434A
Expired / Lapsed
US
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Implantable medical devices of shape memory alloy
Assignee: Litana Ltd
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Filing: 1997-08-12
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Granted: 1999-03-02
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Expires: 2017-08-12
Abstract
Abstract A medical device which comprises a shape memory alloy (SMA) portion which is deformable from an undeformed first configuration assumed by it in an austenitic state of the SMA to a deformed second configuration, whereby the SMA is converted into a strain-induced martensite or partial martensite. This conversion increases the temperature of transformation (A s ) from an initial transformation temperature A s ° to a temperature A s '. When the SMA, once in the second configuration, is heated to a temperature higher than A s ', it transforms to an at least partial austenite and it transforms towards the undeformed first configuration with a decrease of A s from A s ' to A s °. A s ° is below body temperature such that when the device is deployed in the body, after placing it in its target location with the SMA portion in the second configuration and then heating it to assume its first configuration, the SMA is stable in the at least partial austenite at body temperature.
Inventors
- 👤 Josef Flomenblit
- 👤 Nathaly Budigina
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 00:29
CPC Classifications
C; C22; C22F; C22F1/00; C22F1/10; A; A61; A61F; A61F2/00; A61F2/82; A61F2/86; A61F2/88; A61C; A61C8/00; A61C8/0018; A61C8/0033; A61L; A61L27/00; A61L27/02; A61L27/04; A61L27/06; A61L31/00; A61L31/02; A61L31/022; C22F1/006; A61C2201/00; A61C2201/007; A61F2210/00; A61F2210/0014; A61F2210/0023; A61F2210/0042; A61F2310/00; A61F2310/00005; A61F2310/00011; A61F2310/00023; A61L2400/00; A61L2400/16
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
267 words
A medical device comprising a shape memory alloy (SMA) portion having an austenitic and a martensitic state with a different configuration in each of these states, the SMA being transformable from a martensitic to an austenitic state by an austenitic transformation occurring in a temperature range between A s , a start temperature of the austenitic transformation, to A f , a finish temperature of the austenitic transformation, and being transformable from an austenitic state to a martensitic state by a martensitic transformation occurring in a temperature range lower than body temperature between M s , a start temperature of a martensitic transformation and M f , a finish temperature of the martensitic transformation, A s being lower than body temperature in an undeformed state; the device being characterized in that: the SMA portion is deformable from an undeformed first configuration assumed by it in the austenitic state to a deformed second configuration, such that the deformation converts it into a strain-induced martensitic or partial martensite with an increase in A s from its original temperature A s °, to a temperature A s '; and in that when the SMA portion, once in said second configuration, is heated to a temperature higher than A s ', it transforms to an at least partial austenitic state, which transformation results in a change in configuration from the deformed second configuration towards the undeformed first configuration and in a decrease of A s from A s ' to A s °, such that the SMA portion is stable in the at least partial austenitic state at the body temperature.
Claim 2
Dependent Claim
267 words
A medical device comprising a shape memory alloy (SMA) portion having an austenitic and a martensitic state with a different configuration in each of these states, the SMA being transformable from a martensitic to an austenitic state by an austenitic transformation occurring in a temperature range between A s , a start temperature of the austenitic transformation, to A f , a finish temperature of the austenitic transformation, and being transformable from an austenitic state to a martensitic state by a martensitic transformation occurring in a temperature range lower than body temperature between M s , a start temperature of a martensitic transformation and M f , a finish temperature of the martensitic transformation, A s being lower than body temperature in an undeformed state; the device being characterized in that: the SMA portion is deformable from an undeformed first configuration assumed by it in the austenitic state to a deformed second configuration, such that the deformation converts it into a strain-induced martensitic or partial martensite with an increase in A s from its original temperature A s °, to a temperature A s '; and in that when the SMA portion, once in said second configuration, is heated to a temperature higher than A s ', it transforms to an at least partial austenitic state, which transformation results in a change in configuration from the deformed second configuration towards the undeformed first configuration and in a decrease of A s from A s ' to A s °, such that the SMA portion is stable in the at least partial austenitic state at the body temperature.
Claim 3
Dependent Claim
14 words
A medical device according to claim 1, wherein the shape memory alloy is nitinol.
Claim 4
Dependent Claim
58 words
A medical device according to claim 1, wherein at least one portion of the SMA is deformable to a higher strain than the remainder of the SMA such that said at least one portion has an A s ' temperature t 2 which is greater than the A s ' temperature of the remainder SMA, t 1 .
Claim 5
Dependent Claim
52 words
A medical device according to claim 3, to be deployed in the body by heating the SMA to a temperature higher than t 1 but less than t 2 , whereby said at least one portion remains in a martensitic state during deployment and the remainder of the SMA transforms to austenitic.
Claim 6
Dependent Claim
15 words
A medical device according to claim 1, wherein A s ' is above body temperature.
Claim 7
Dependent Claim
23 words
A medical device according to claim 1, wherein A s ' is below body temperature and A f ' is above body temperature.
Claim 8
Dependent Claim
37 words
A medical device according to claim 1, being a member of the group consisting of a medical stent, a tooth implant, a bone fracture healing device, a heart implant, a bone plate and an intrauterine contraceptive device.
Claim 9
Independent Claim
316 words
A method of deploying a medical device within the human body, the medical device comprising a shape memory alloy (SMA) portion having an austenitic and a martensitic state with a different configuration in each of these states and having associated M s , M f , A s and A f temperatures, being start and finish temperatures of the SMA's martensitic transformation and the start and finish temperature of the SMA's austenitic transformation, respectively, A s having the value A s ° which being less than body temperature, when the medical device is in an undeformed state, and M s being less than A s , the method comprising the steps of: heating the SMA to a temperature greater than A s , thereby placing the SMA in at least a partial austenitic state; cooling the medical device to a temperature between A s and M s ; deforming the medical device from an undeformed first configuration assumed by it in the austenitic state to a deformed second configuration, said deforming resulting in an increase in A s from A s ° to A s ', the SMA portion being in a martensitic or partial martensitic state after said deforming; positioning the medical device to a target location within the body, the SMA portion remaining in the martensitic or partial martensitic state during said positioning; and transforming the SMA portion from the martensitic or partial martensitic state to at least a partial austenitic state by heating it to a temperature higher than A s ', said transforming resulting in a change in the configuration of the SMA portion from the deformed second configuration towards the undeformed first configuration, the change in configuration resulting in a decrease in A s from A s ' to A s ° such that the medical device is stable in at least a partially austenitic state while deployed in the body.
Claim 10
Independent Claim
316 words
A method of deploying a medical device within the human body, the medical device comprising a shape memory alloy (SMA) portion having an austenitic and a martensitic state with a different configuration in each of these states and having associated M s , M f , A s and A f temperatures, being start and finish temperatures of the SMA's martensitic transformation and the start and finish temperature of the SMA's austenitic transformation, respectively, A s having the value A s ° which being less than body temperature, when the medical device is in an undeformed state, and M s being less than A s , the method comprising the steps of: heating the SMA to a temperature greater than A s , thereby placing the SMA in at least a partial austenitic state; cooling the medical device to a temperature between A s and M s ; deforming the medical device from an undeformed first configuration assumed by it in the austenitic state to a deformed second configuration, said deforming resulting in an increase in A s from A s ° to A s ', the SMA portion being in a martensitic or partial martensitic state after said deforming; positioning the medical device to a target location within the body, the SMA portion remaining in the martensitic or partial martensitic state during said positioning; and transforming the SMA portion from the martensitic or partial martensitic state to at least a partial austenitic state by heating it to a temperature higher than A s ', said transforming resulting in a change in the configuration of the SMA portion from the deformed second configuration towards the undeformed first configuration, the change in configuration resulting in a decrease in A s from A s ' to A s ° such that the medical device is stable in at least a partially austenitic state while deployed in the body.
Claim 11
Dependent Claim
13 words
A method according to claim 8, wherein the shape memory alloy is nitinol.
Claim 12
Dependent Claim
61 words
A method according to claim 8, wherein at least one portion of the SMA is deformed to a higher strain than the remainder of the SMA during said deforming, such that the at least one portion has an A s ' temperature t 2 , higher than the A s ' temperature of the remainder of the SMA, t 1 .
Claim 13
Dependent Claim
44 words
A method according to claim 10, wherein the SMA is heated to a temperature higher than t 1 but less than t 2 such that the at least one portion remain in a martensitic state and the remainder of the SMA transforms to austenite.
Claim 14
Dependent Claim
37 words
A method according to claim 11, further comprising heating the SMA to a temperature higher than t 2 after said transforming step, thereby transforming the at least one portion from a martensitic state to an austenitic state.
Claim 15
Dependent Claim
39 words
A method according to claim 11, further comprising removing the medical device from the body by gripping the at least one portion of a higher strain which had been transformed during heating to a temperature about t 2 .
Claim 16
Independent Claim
276 words
A method of deploying a medical device within the human body, the medical device comprising a shape memory alloy (SMA) portion having an austenitic and a martensitic state with a different configuration in each of these states and having associated M s , M f , A s and A f temperatures, being start and finish temperatures of the SMA's martensitic transformation and the start and finish temperature of the SMA's austenitic transformation, respectively, A s having the value A s °, which is less than body temperature, when the medical device is in an undeformed state, the method comprising the steps of: deforming the medical device by transforming it from an undeformed first configuration assumed by it in the austenitic state to a deformed second configuration, said deforming resulting in an increase in A s from A s ° to A s ', the SMA portion being in a strain-induced martensitic or partial martensitic state after said deforming; positioning the medical device to a target location within the body, the SMA portion remaining in the strain-induced martensitic or partial martensitic state during said positioning; and transforming the SMA portion from said martensitic or partial martensitic state to at least a partial austenitic state by heating it to a temperature higher than A s ', said transforming resulting in a change in the configuration of the SMA portion from the deformed second configuration towards the undeformed first configuration, the change in configuration resulting in a decrease in A s from A s ' to A s ° such that the medical device is stable in at least a partially austenitic state while deployed in the body.
Claim 17
Independent Claim
276 words
A method of deploying a medical device within the human body, the medical device comprising a shape memory alloy (SMA) portion having an austenitic and a martensitic state with a different configuration in each of these states and having associated M s , M f , A s and A f temperatures, being start and finish temperatures of the SMA's martensitic transformation and the start and finish temperature of the SMA's austenitic transformation, respectively, A s having the value A s °, which is less than body temperature, when the medical device is in an undeformed state, the method comprising the steps of: deforming the medical device by transforming it from an undeformed first configuration assumed by it in the austenitic state to a deformed second configuration, said deforming resulting in an increase in A s from A s ° to A s ', the SMA portion being in a strain-induced martensitic or partial martensitic state after said deforming; positioning the medical device to a target location within the body, the SMA portion remaining in the strain-induced martensitic or partial martensitic state during said positioning; and transforming the SMA portion from said martensitic or partial martensitic state to at least a partial austenitic state by heating it to a temperature higher than A s ', said transforming resulting in a change in the configuration of the SMA portion from the deformed second configuration towards the undeformed first configuration, the change in configuration resulting in a decrease in A s from A s ' to A s ° such that the medical device is stable in at least a partially austenitic state while deployed in the body.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2002-03-01 | 2002-08-31 | 2003-03-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2006-03-01 | 2006-08-31 | 2007-03-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2010-03-01 | 2010-08-31 | 2011-03-02 | $7700.00 | Window Closed / Lapsed |