Internal osteodistraction device
Inventors
Haaja, Juha • Ritvanen, Antti • Turunen, Markus • Hallila, Harri
Assignees
Interested in licensing this patent?
MTEC can help explore whether this patent might be available for licensing for your application.
Publication Number
US-8632544-B2
Publication Date
2014-01-21
Expiration Date
Abstract
The invention relates to an internal osteodistraction device, which includes two fixing points (7, 8) for attachment to a bone in such a way that the distance between the fixing points can be increased in a controlled manner, and a magnetostrictive element (1) which produces a reciprocating mechanical motion in a changing magnetic field. The magnetostrictive element is configured for taking up solely a compressive or tensile force, such that the magnetostrictive element pushes a unidirectional movement permitting element which allows for an increase in the distance between the fixing points, and as the magnetostrictive element is in the process of returning to its original length, a second unidirectional movement permitting element allows the magnetostrictive element to resume its original length without changing a distance between the fixing points of the distraction device.
Core Innovation
The invention relates to an internal osteodistraction device that includes two fixing points for attachment to a bone in a manner that enables increasing the distance between the fixing points in a controlled manner. The device uses a magnetostrictive element that is capable of producing a reciprocating mechanical motion in a changing magnetic field, including a magnetostrictive element implemented using giant magnetostrictive material such as Terfenol-D.
When the magnetostrictive element is only subjected to compressive or tensile forces, it pushes a member that engages unidirectional movement permitting elements to allow increasing a distance between the fixing points. As the magnetostrictive element returns to its original length, a second member engages the unidirectional movement permitting elements so that the distance between the fixing points does not change substantially or retracts to a lesser extent than the increase resulting from the pushing action.
The magnetostrictive element acts on the members that engage the unidirectional movement permitting elements, and the members and unidirectional movement permitting elements are located only between the magnetostrictive element and one of the two fixing points. The internal osteodistraction device can include an optional superelastic NiTi (Nitinol) replacement of a spring, and the unidirectional movement permitting elements can be implemented with barbs/ratchet elements or a ball screw with ball nuts and one-way clutches.
Claims Coverage
The independent claim contains three main inventive feature sets: a magnetostrictive element producing reciprocating mechanical motion in a changing magnetic field combined with a controlled distraction function, a two-member unidirectional movement permitting arrangement that prevents substantial return-distance change, and a structural location limitation where the members and unidirectional movement permitting elements are located only between the magnetostrictive element and one of the two fixing points. Dependent claims refine implementation details of biasing/retraction, unidirectional movement permitting element structure, and adjustability.
Reciprocating magnetostrictive osteodistraction in a changing magnetic field
An internal osteodistraction device including two fixing points for attachment to a bone that enables increasing the distance between the fixing points in a controlled manner, and a magnetostrictive element capable of producing a reciprocating mechanical motion in a changing magnetic field.
Two-member unidirectional movement permitting for controlled distraction without substantial return change
When the magnetostrictive element is only subjected to compressive or tensile forces, the magnetostrictive element pushes a member that engages unidirectional movement permitting elements to allow increasing a distance between the fixing points, and as the magnetostrictive element returns to its original length, a second member engages the unidirectional movement permitting elements so that the distance between the fixing points does not change substantially or retracts to a lesser extent than the increase resulting from the pushing action.
Location of members and unidirectional movement permitting elements
The magnetostrictive element acts on the members that engage the unidirectional movement permitting elements, and the members and unidirectional movement permitting elements are located only between the magnetostrictive element and one of the two fixing points.
Superelastic retraction or bias element for the magnetostrictive element
The unidirectional movement permitting elements cooperate with or are associated with a superelastic element such that the superelastic element generates a retraction force and or bias to the magnetostrictive element.
Shape memory alloy unidirectional movement permitting element
The unidirectional movement permitting elements include a shape memory alloy element.
Barbs or ratchets as unidirectional movement permitting elements
The unidirectional movement permitting elements are implemented using barbs or ratchet members.
Ball nut and one-way clutch as unidirectional movement permitting elements
The unidirectional movement permitting elements include a ball nut and a one-way clutch.
Adjustable device length and maximum strain length by cutting or selecting components
The length and maximum strain length of the device can be adjusted by cutting or by selecting appropriate components.
Across the independent claim and refinements, the device combines a magnetostrictive element producing reciprocating motion in a changing magnetic field with members engaging unidirectional movement permitting elements to increase the distance between two fixing points while limiting change during return. The claim set further limits placement of the members and unidirectional movement permitting elements and refines implementation via superelastic or biasing, shape memory alloy, barbs or ratchets, ball nut or one-way clutch, and adjustability by cutting or selecting components.
Stated Advantages
Enables increasing the distance between the fixing points in a controlled manner.
Prevents the distance between the fixing points from changing substantially during return or retracting less than the prior increase.
Documented Applications
No documented applications found
Interested in licensing this patent?