Prosthesis (i.e. – artificial body members) – parts thereof – or ai – Implantable prosthesis – Bone
Patent
1998-01-26
1999-10-05
Milano, Michael J.
Prosthesis (i.e., artificial body members), parts thereof, or ai
Implantable prosthesis
Bone
606 62, A61F 228
Patent
active
059615532
DESCRIPTION:
BRIEF SUMMARY
The present invention concerns the devices used for elongating long bones such as the femur, tibia and humerus, and it relates more particularly to a device for progressive control of one such elongation device.
Femoral bones of unequal length and cases of dwarfism are presently treated using purely mechanical bone elongation devices.
Although these are satisfactory in terms of the function required of them, these devices, which are called external fixators, restrict the patient and are associated with a very high rate of complications.
Devices for elongating long bones are also known which comprise an intramedullary nail which includes a tubular sleeve, an extension which can slide axially inside the sleeve, the sleeve and the extension being equipped with members for rigidly connecting them to two bone portions separated by an osteotomy, and means for moving the extension in the sleeve, capable of imparting to the intramedullary nail, and to the bone in which it is fixed, a gradual elongation which is obtained automatically or by an external action, the said system being entirely enclosed within the body and the bone in question.
Such a nail, described in European Patent Application No. 0 346 247, filed May 22, 1989 by the Applicant, is made up of several elements which are capable of imparting to the nail a gradual elongation, resulting from a partial rotation applied to the limb in question and a return to the original position.
An elongation device for long bones is also known which comprises an intramedullary nail which includes a tubular sleeve, an extension which can slide axially inside the sleeve, the sleeve and the extension being equipped with members for rigidly connecting them to two portions of the fractured bone, and means for moving the extension in the sleeve, these means of movement comprising a wire which is made of a shape-memory alloy and is arranged axially in the sleeve between one end of the latter and one end of the extension to which the contiguous end part of the wire is fixed, mechanical means for transforming the compressive force, which is produced by the shape-memory wire under the action of successive cycles of heating and cooling of the said wire, into an axial force of distraction exerted on the extension and tending to bring it partially out of the sleeve, means for induction heating of the shape-memory wire, and a generator of heat energy by induction which is provided with a transmitting antenna intended to surround the patient's limb in which the bone is equipped with the intramedullary nail, and designed to cyclically activate the means of heating the shape-memory wire in order to initiate gradual forward movements of the extension so as to bring about an elongation of the nail and consequently an elongation of the bone.
Such an intramedullary nail, described in European Patent Application No. 0 346 247, makes it possible to obtain an elongation, for a long bone such as the femur, of up to 10 cm, and it avoids the problems of sepsis occasioned by the use of an elongation device with external control, as well as the risks of angular deviation during elongation by virtue of the intramedullary guiding.
This elongation nail also permits the formation of a bone callus, followed by a consolidation of lamellar bone which is of substantially better quality than that obtained by the external fixators, and in theory it requires only two operations, one--for its implantation and the other for its removal.
Moreover, it limits the number of scars and in particular limits their size, which represents an important psychological benefit for the patient.
Finally, this type of internal fixator allows the patient to remain active without handicap during the second half of the duration of treatment and avoids the aesthetic problems.
On the other hand, the callus (or osteon) which is formed between the two halves of the bone, and which joins them together, is necessarily broken by the repeated 15.degree. rotations of the leg (30 times a day) in order to obtain a daily elongation of 2 mm,
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patent: 5415660 (1995-05-01), Campbell
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patent: 5626579 (1997-05-01), Muschler
patent: 5626581 (1997-05-01), Staehlin
patent: 5704938 (1998-01-01), Staehlin
by K. Koshiji et al., "Externally-Coupled Transcutaneous Energy Transmission System for a Totally Implantable Artificial Heart", Proceedings of the Annual International Conference of the IEEE Engineering in Medicine and Biology Society, vol. 15, Oct. 1993, pp. 909-910.
Coty Alain
Favreul Emmanuel
L'Homme Michel
Palay Dror
Peretti Giovani
Medinov-Amp
Milano Michael J.
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