Surgery – Instruments – Orthopedic instrumentation
Patent
1987-11-20
1990-05-01
Hafer, Robert A.
Surgery
Instruments
Orthopedic instrumentation
606 96, A61B 1760
Patent
active
049209590
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
Our present invention relates to an external fixture for osteosynthesis and, more particularly, to a fixture with at least one bridge member on which several holders are orientable and screw-tightenable by means of clamping jaw surfaces, which in turn have cylindrical holder openings closable by operating screws and thereby serve as clamp holders each for one bone nail or screw.
BACKGROUND OF THE INVENTION
The book "Current Concepts of External Fixation of Fractures", by Uhthoff and Stahl, Springer-Verlag, Berlin Heidelberg N.Y., 1982, pp. 99-102 describes earlier fixtures for osteosynthesis.
The previously known external fixture contains two approximately circular cylindrical steel disks of the same circumference traversed coaxially by a common clamp screw. In the space between both clamping disks a thin friction disk can be provided. A clamping disk of the clamping disk pair has two secantial and cylindrical passages extending parallel to each other for receiving the bridge members (fixture frame rods) which penetrate the radial circular surfaces facing the neighboring clamping disk. Two receiving passages longitudinally slotted over a comparatively large peripheral region thus result, in which the fixture frame rods projecting from one side alongside the longitudinal slots must be pushed in axially.
The cylindrical holder openings for receiving either a bone nail (e.g. a Steinmann nail) or a bone screw (e.g. a Schanze screw) are formed in the previously known fixture analogous to the described cylindrical passages for the fixture frame rods as cylindrical passages longitudinally slotted along one side.
Clamping of a fixture frame rod and a bone screw is effected in the known external fixture therefore jointly by tightening the central clamping screw so that both clamping disks are pressed against each other axially with their circular front surfaces facing and, the peripheral portions of the fixture frame rod and the bone screw protruding from the longitudinal slot of the receiving passages are clamped between them.
The external fixtures described by the book "Current Concepts of External Fixation of Fractures", differs significantly from the earlier fixtures and this device offers the advantage of a simple structure including fewer components, however, this device requires improvement with regard to its handling during operation and the subsequent care of the patient.
OBJECT OF THE INVENTION
Departing from the fixture described in the book "Current Concepts of External Fixation of Fractures", it is the object of the invention to improve the heretofore known external fixture operationally, by preserving its advantageously simple structure.
SUMMARY OF THE INVENTION
As opposed to the afore-mentioned known external fixture described in "Current Concepts of External Fixation of Fractures" each cylindrical holder opening consists of a single connected wall surface which is deformable elastically or plastically by operation of a screw element to such an extent that the cylindrical holder opening acts as a drill or screw guide and-after progressively closing and/or constricting it--for clamping a bone nail and/or for the bone screw. According to the invention it is basically possible to close the cylindrical holder opening separately or--analogous to the known fixture--jointly with adjacent clamp jaw surfaces which receive the bridge member (particularly the fixture frame rod).
According to that, the first possibility of such an alternative the cylindrical holder openings are closable on tightening the operating screw by elastic or plastic deformation relative to the bridging member or component first in the sense of an preadjustment and then are deformable with the bone nail and/or with the bone screw with an additional closure stroke from position in which the opening or passage forms a drill and/or screw guide until the passage reaches its final clamped configuration.
In a further embodiment, the second possibility of such an alternative construction, the cylindrical holder
REFERENCES:
patent: 2391693 (1945-12-01), Ettinger
patent: 2393694 (1946-01-01), Kirschner
patent: 4475546 (1984-10-01), Patton
patent: 4483334 (1984-11-01), Murray
patent: 4620533 (1986-11-01), Mears
patent: 4693240 (1987-09-01), Evans
Muller Karl H.
Witzel Ulrich
Dubno Herbert
Hafer Robert A.
Rooney Kevin G.
Witzel Ulrich
LandOfFree
External fixture for osteosynthetis does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with External fixture for osteosynthetis, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and External fixture for osteosynthetis will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-823667