Surgery – Instruments – Orthopedic instrumentation
Reexamination Certificate
1998-11-18
2001-03-20
Reip, David O. (Department: 3731)
Surgery
Instruments
Orthopedic instrumentation
C606S075000, C606S096000, C606S104000
Reexamination Certificate
active
06203544
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention relates to a fixation element for osteosynthesis in the human or animal body. Fixation elements of this kind are known in principle and serve to fixate bone fragments, e.g. in distal radius fractures. In this it is known in the framework of the so-called bore wire osteosynthesis to stabilise distal radius fractures with Kirschner's wire, which is however disadvantageous in a number of regards. On the one hand, infections can arise after the insertion of these metallic wires. On the other hand, metal allergies can arise. Finally, a second operation is always required after the healing of the fracture in which the metallic elements are removed.
Furthermore, it is known to use fixation elements of plastic which are absorbed in the body for the fixation of fractures. To a high percentage, however, plastic elements of this kind lead to foreign-body reactions and osteolyses. In addition their bending strength decreases very strongly in a period of time of about 2-3 weeks so that the stability required for the bone healing is not sufficiently ensured.
SUMMARY OF THE INVENTION
The problem (object) lying at the basis of the invention is to provide a fixation element of the initially named kind by means of which a stable and lasting fixing of bone fragments can be achieved and in which a second operation for the removal of foreign bodies can be dispensed with.
The satisfaction of this object takes place through the features of claim
1
and in particular in that the fixation element consists of cortical bone matter which is conserved and sterilised. In accordance with the invention a fixation element of cortical bone is inserted which has a lower strength per se than a Kirschner's wire. It has however proved that it is sufficient to use a weaker material than metal for the fixation of bone fragments, with the advantages resulting in the use of fixation implants of cortical bone matter that foreign-body reactions are eliminated, no metal allergies can arise and a second operation for the removal of the foreign body can be dispensed with. Through this the total costs of the healing process are greatly reduced, with the dangers connected with an additional narcosis or a second operation also being eliminated.
The fixation element in accordance with the invention is anchored in the bone fragments, through which the osteosynthesis becomes more stable than in the use of absorbable plastic pins. In addition the cortical bone matter is transformed into the body's own bone matter so that an optimal healing of the fracture can be achieved.
In accordance with the invention cortical fixation elements can be used which are produced from allogenic or xenogenic bone matter.
Advantageous embodiments of the invention are described in the description, the figures and the subordinate claims.
In accordance with a first advantageous embodiment the fixation element can be designed as a screw or a nail. Embodiments of this kind of fixation elements are admittedly known in principle, but lead to particular advantages in conjunction with the material in accordance with the invention, however.
In accordance with a further embodiment of the invention a section with a reduced cross-section can be provided in the region of the front end of the pin or the nail with a reduced cross-section. Through this there results the great advantage that the fixation element can be anchored in a bore at the opposite corticalis of the radius bone, with it not being possible for the main body of the fixation element to slip through this bore, which leads to a very stable connection.
The transition to the section with reduced cross-section preferably extends conically, with an angle of about 45° to the longitudinal axis of the fixation element having proved particularly advantageous in order to achieve a fixed anchoring in the opposite corticalis.
It is advantageous when the cross-section of the contracted section amounts to about 80 to 85% of the cross-section of the remaining fixation element, preferably between about 3 and 5 mm
2
.
The contracted section can extend over about 10 to 20% of the total length of the fixation element, preferably over about 10 mm. Such a length is sufficient in order to ensure a good and firm anchoring in the opposite corticalis.
In accordance with a further exemplary embodiment of the invention the fixation element is designed as a screw and preferably has placement surfaces for a wrench. Screws of this kind are admittedly known in principle as fixation elements, but the initially mentioned advantages result through the use of cortical bone matter.
In the screw-like fixation element it is particularly advantageous when the transition between the screw head and the screw body extends conically, through which a collar is formed, which is supported on the bone fragment to be fixated. The collar permits the projecting screw head to be sawed off in the event that this is necessary.
A setting tool in accordance with the invention for pin-shaped fixation elements has two sleeve-like guides, which can be fixed relative to one another at a selectable acute angle. Through this the fixation element in accordance with the invention can be used more readily in different planes and at different angles with the help of the fixing wire. Through the guides, which are adjustable relative to one another, the size of the angle between the guide wire, which is inserted through one of the sleeves, and the fixation element to be inserted, which is held by the other guide, can easily be adjusted.
REFERENCES:
patent: 4781182 (1988-11-01), Purnell et al.
patent: 5122132 (1992-06-01), Bremer
patent: 5868749 (1999-02-01), Reed
patent: 29 06 650 C2 (1989-05-01), None
patent: 40 04 941 A1 (1990-08-01), None
patent: 39 23 411 A1 (1991-01-01), None
patent: 42 05 118 C1 (1994-06-01), None
patent: 43 00 039 C1 (1994-09-01), None
patent: 44 06 374 A1 (1994-09-01), None
patent: 195 04 955 A1 (1996-08-01), None
patent: 0 674 880 A1 (1995-03-01), None
patent: WO 97/25945 (1997-07-01), None
patent: WO 97/37603 (1997-10-01), None
Albee, Fred H., Bone Graft Surgery in Disease, Injury and Deformity, D. Appleton-Century Company, New York, 1940: pp. 216, 217 and 220, 1940.*
Habal and Reddi,Bone Grafts&Bone Substitutes, W.B. Saunders Company, Philadelphia, et al. 1992: Chapters 2-3, pp. 6-10.
Fitch Even Tabin & Flannery
Reip David O.
Tutogen Medical, Inc.
LandOfFree
Fixation element does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Fixation element, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Fixation element will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2446884