US5626581A
Expired / Lapsed
US
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Implantable bone lengthening apparatus
Assignee: Volunteers for Medical Engr
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Filing: 1995-11-27
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Granted: 1997-05-06
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Expires: 2015-11-27
Abstract
Abstract An implantable bone lengthening apparatus may utilize an entirely self-contained lengthening mechanism which includes a shape memory material-powered hydraulic pump, a shape memory material-powered ratchet mechanism, a permeable head piston mechanism, and a bellows extension mechanism. The bone lengthening nails are more compact, simpler, eliminate unnecessary shifting or torsional movement, and maintain alignment of the bone during its natural healing process.
Inventors
- 👤 John H. Staehlin
- 👤 Amy Corvelli
- 👤 Stanley Lu
- 👤 Garret Taylor
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 04:44
CPC Classifications
A; A61; A61B; A61B17/00; A61B17/56; A61B17/58; A61B17/68; A61B17/72; A61B17/7216; A61B2017/00535; A61B2017/00539; A61B2017/00831; A61B2017/00867
Claims Analysis
Total Claims: 29
Claim 1
Independent Claim
81 words
A bone lengthening nail assembly comprising: a first nail body section; a second nail body section; and a power cartridge located within either of said first or second nail body sections and including a powered hydraulic pump which forces hydraulic fluid from a hydraulic fluid reservoir and into a sealed chamber between said first and second sections thereby forcing said first nail section to extend longitudinally relative to said second nail section, and increasing the length of said bone lengthening nail.
Claim 2
Dependent Claim
81 words
A bone lengthening nail assembly comprising: a first nail body section; a second nail body section; and a power cartridge located within either of said first or second nail body sections and including a powered hydraulic pump which forces hydraulic fluid from a hydraulic fluid reservoir and into a sealed chamber between said first and second sections thereby forcing said first nail section to extend longitudinally relative to said second nail section, and increasing the length of said bone lengthening nail.
Claim 3
Dependent Claim
145 words
The bone lengthening nail assembly of claim 1, wherein: said hydraulic pump includes; a low pressure inlet section; a high pressure discharge section; a check valve located between said low pressure inlet section and said high pressure discharge section to prevent fluid backflow; a pump piston body for conveying fluid from said low pressure section through said check valve to said high pressure discharge section said pump piston body being adjacent to a first spring made of a shape memory material located on one side of the pump piston body; and a second spring located on the opposing side of the pump piston body, wherein the shape memory material has a first phase in which the first spring has a lower elastic modulus than said second spring and a second phase in which said first spring has a higher elastic modulus than said second spring.
Claim 4
Dependent Claim
22 words
The bone lengthening nail of claim 1, wherein: said first nail body section is slidably received in said second nail body section.
Claim 5
Dependent Claim
53 words
The bone lengthening nail of claim 2, wherein: said pump piston body has a channel longitudinally extending therethrough, said check valve being located therein to enable fluid to be passed through said pump piston body during a return stroke, but prevent fluid from passing through said pump piston body during a pressurizing stroke.
Claim 6
Dependent Claim
72 words
The bone lengthening nail of claim 2, wherein: a channel body is located downstream from said pump piston body, said channel body having a channel longitudinally extending therethrough and check valve located therein to enable fluid to be passed through said channel body during the pressurizing stroke, but to prevent fluid from passing through said channel body in the direction opposite to the direction in which the pump piston body is located.
Claim 7
Dependent Claim
27 words
The bone lengthening nail of claim 2, wherein said shape memory material is transformed from the first phase to the second phase by the application of heat.
Claim 8
Dependent Claim
14 words
The bone lengthening nail of claim 6, wherein said shape memory material is nitinol.
Claim 9
Dependent Claim
136 words
A hydraulic pump comprising: a low pressure inlet section; a high pressure discharge section; a check valve located between said low pressure inlet section and said high pressure discharge section to prevent fluid backflow; a pump piston body for conveying fluid from said low pressure section through said check valve to said high pressure discharge section said pump piston body being adjacent to a first spring made of a shape memory material located on one side of the pump piston body; and a second spring located on the opposing side of the pump piston body, wherein the shape memory material has a first phase in which the first spring has a lower elastic modulus than the second spring, and a second phase in which said first spring has a higher elastic modulus than said second spring.
Claim 10
Dependent Claim
136 words
A hydraulic pump comprising: a low pressure inlet section; a high pressure discharge section; a check valve located between said low pressure inlet section and said high pressure discharge section to prevent fluid backflow; a pump piston body for conveying fluid from said low pressure section through said check valve to said high pressure discharge section said pump piston body being adjacent to a first spring made of a shape memory material located on one side of the pump piston body; and a second spring located on the opposing side of the pump piston body, wherein the shape memory material has a first phase in which the first spring has a lower elastic modulus than the second spring, and a second phase in which said first spring has a higher elastic modulus than said second spring.
Claim 11
Dependent Claim
52 words
The hydraulic pump of claim 8, wherein: said pump piston body has a channel longitudinally extending therethrough said check valve being located therein to enable fluid to be passed through said pump piston body during a return stroke, but prevent fluid from passing through said pump piston body during a pressurizing stroke.
Claim 12
Dependent Claim
71 words
The hydraulic pump of claim 8, wherein: a channel body is located downstream from said pump piston body, said channel body having a channel longitudinally extending therethrough and cheek valve located therein to enable fluid to be passed through said channel body during a pressurizing stroke, but to prevent fluid from passing through said channel body in the direction opposite to the direction in which the pump piston body is located.
Claim 13
Dependent Claim
26 words
The hydraulic pump of claim 8, wherein said shape memory material is transformed from the first phase to the second phase by the application of heat.
Claim 14
Dependent Claim
13 words
The hydraulic pump of claim 11, wherein said shape memory material is nitinol.
Claim 15
Dependent Claim
114 words
A bone lengthening nail assembly comprising: a first nail body section having grooves located therein and a longitudinal axis; a second nail body section; a reciprocating ratchet mechanism located in said second nail body section and extending into said first nail body section; fingers located on said ratchet mechanism which extend into said grooves; and a shape memory material spring attached to said ratchet mechanism which has a first phase in which said spring is compact and a second phase in which said spring is extended said shade memory material causing said ratchet mechanism to alternately move back and forth along the longitudinal axis of the first nail body section in a reciprocating movement.
Claim 16
Dependent Claim
114 words
A bone lengthening nail assembly comprising: a first nail body section having grooves located therein and a longitudinal axis; a second nail body section; a reciprocating ratchet mechanism located in said second nail body section and extending into said first nail body section; fingers located on said ratchet mechanism which extend into said grooves; and a shape memory material spring attached to said ratchet mechanism which has a first phase in which said spring is compact and a second phase in which said spring is extended said shade memory material causing said ratchet mechanism to alternately move back and forth along the longitudinal axis of the first nail body section in a reciprocating movement.
Claim 17
Dependent Claim
69 words
The bone lengthening nail of claim 13, wherein: said grooves have a first sloping face located in the direction of said second nail body section and a second face in the direction of said first body section; and said fingers have faces which cooperate with said groove faces such that said fingers can translate relative to said grooves only in the direction away from said first nail body section.
Claim 18
Dependent Claim
38 words
The bone lengthening nail of claim 13, wherein: second springs oppose said shape memory material springs and have an elastic modulus value between the elastic modulus of the first phase and the elastic modulus of the second phase.
Claim 19
Dependent Claim
20 words
The bone lengthening nail of claim 15, wherein said shape memory material springs and said second springs are belleville springs.
Claim 20
Dependent Claim
14 words
The bone lengthening nail of claim 13, wherein said shape memory material is nitinol.
Claim 21
Dependent Claim
89 words
The bone lengthening nail of claim 13, wherein: said grooves have a first sloping face located in the direction of said second nail body section and a second face in the direction of said first body section; and buttress arms are rigidly attached to said second nail body section, extend into said first nail body section, and have faces which cooperate with said groove faces such that said first body section can translate relative to said buttress arms only in the direction away from said second nail body section.
Claim 22
Dependent Claim
31 words
The bone lengthening nail of claim 18, wherein: said fingers and said buttress arms are located in the same plane perpendicular to the longitudinal axis of said first nail body section.
Claim 23
Dependent Claim
71 words
A bone lengthening nail assembly comprising: a first nail body section and a second nail body section; a chamber located in said second nail body section, said chamber filled with fluid; a permeable piston head attached to said first nail body section and extending into said chamber; and springs which force said permeable piston head to move longitudinally through said chamber, thereby forcing said fluid to permeate through said piston head.
Claim 24
Dependent Claim
71 words
A bone lengthening nail assembly comprising: a first nail body section and a second nail body section; a chamber located in said second nail body section, said chamber filled with fluid; a permeable piston head attached to said first nail body section and extending into said chamber; and springs which force said permeable piston head to move longitudinally through said chamber, thereby forcing said fluid to permeate through said piston head.
Claim 25
Dependent Claim
17 words
The bone lengthening nail of claim 20, wherein said springs are made of a shape memory material.
Claim 26
Dependent Claim
14 words
The bone lengthening nail of claim 21, wherein said shape memory material is nitinol.
Claim 27
Dependent Claim
98 words
A bone lengthening nail assembly comprising: a first nail body section and a second nail body section; a chamber located in said second nail body section; a piston head attached to said first nail body section and extending into said chamber; a longitudinally expanding bellows located in said chamber and attached to said piston head and second nail body section, wherein said bellows comprises a sealed volume which expands as said bellows is filled with fluid; and a pump for falling said bellows with a fluid, thereby causing said bellows to expand, and causing said nail to extend.
Claim 28
Dependent Claim
98 words
A bone lengthening nail assembly comprising: a first nail body section and a second nail body section; a chamber located in said second nail body section; a piston head attached to said first nail body section and extending into said chamber; a longitudinally expanding bellows located in said chamber and attached to said piston head and second nail body section, wherein said bellows comprises a sealed volume which expands as said bellows is filled with fluid; and a pump for falling said bellows with a fluid, thereby causing said bellows to expand, and causing said nail to extend.
Claim 29
Dependent Claim
41 words
The bone lengthening nail of claim 23, wherein said pump includes a fluid injection rod surrounded by a pressurizable bladder attached to a pressure source, said fluid injection rod being actuable, by said bladder to inject the fluid into the bellows.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2000-05-05 | 2000-11-04 | 2001-05-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2004-05-05 | 2004-11-04 | 2005-05-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2008-05-05 | 2008-11-04 | 2009-05-06 | $7700.00 | Window Closed / Lapsed |