Surgery – Instruments – Orthopedic instrumentation
Patent
1997-05-13
1998-11-17
Tucker, Guy V.
Surgery
Instruments
Orthopedic instrumentation
606 96, A61B 1776
Patent
active
058369503
DESCRIPTION:
BRIEF SUMMARY
This application is a 35 U.S.C. 371 application based on PCT/SE95/01379, filed Nov. 21, 1995.
BACKGROUND OF THE INVENTION
BRIEF DESCRIPTION OF THE DRAWINGS
The present invention relates to a guide instrument which is adapted for use at operations for fixation of bone fragments at bone fractures, preferably femoral neck fractures, whereby the bone fragments are intended to be fixed relative to each other by means of at least two bone screws, whereby the guide instrument is adapted for guiding a first and a second drill steel which are adapted for drilling passages in the bone fragments for the bone screws.
BRIEF DESCRIPTION OF THE INVENTION
At operations for fixation of bone fragments at fractures, it is important that the bone screws get exact predetermined positions relative to the bone fragments and to each other. For this purpose, bone screws are used having such through center-passages that they can be threaded onto wire-like guide means (so called guide wires). These wire-like guide means are drilled into the bone fragments during TV-roentgen control to exact positions, whereafter the bone screws are threaded onto the wire-like guide means so that said guide means guide said bone screws when said screws are driven into the bone fragments.
Since the wire-like guide means must have room in narrow center passages in the bone screws, they must be thin. This means that the guide means bend easy when they during drilling e.g. come across hard bone after having passed through softer cartilage portions. A wire-like guide means bent in this way during drilling, may lead to that the bone screw is difficult to advance, fasten or tighten and that it is guided to a wrong position. To remedy this problem by redrilling is time consuming and the redrilling can be complicated by the passage already drilled.
The use of wire-like guide means also requires cannulated bone screws, i.e. bone screws having longitudinal center passages, which means that the depth of the threads of the bone screws must be limited.
SUMMARY OF THE INVENTION
The object of the present invention is to remedy or eliminate this problem and this is arrived at according to the invention by means of a guide instrument having primarily the characterizing features of subsequent claim 1.
Since the guide instrument has said characterizing features, it renders it possible to carry through the operation without the use of wire-like guide means and thereby, avoid the problem that such guide means can complicate driving or tightening of the bone screw or guide said bone screw wrong during said driving or said tightening thereof. Furthermore, it is achieved, inter alia, that one can use bone screws without cannulae, i.e. without longitudinal center holes, which means that the threads of the screws can be made deeper and that drilling moments are eliminated during drilling.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will be further described below with reference to the accompanying drawings, wherein
FIG. 1 is a section through a guide instrument according to the invention;
FIG. 2 is a side view of a drill steel which is used together with the guide instrument of FIG. 1 and which after drilling a passage in the bone fragment to be fixed, is retained in said bone fragment;
FIG. 3 is a side view of the guide instrument of FIG. 1 located on said drill steel in a guide position relative to said bone fragment;
FIG. 4 is a side view of the guide instrument of FIG. 1 located in the guide position on said drill steel and while guiding of a second drill steel during drilling of a second bone passage;
FIG. 5 is a side view of the guide instrument of FIG. 1 located in the guide position on said drill steel, whereby the second drill steel has been removed after drilling a second bone passage;
FIG. 6 is a side view of the guide instrument of FIG. 1 located in the guide position on said drill steel and while driving or tightening a bone screw;
FIG. 7 is a side view of the guide instrument of FIG. 1 located in said guide position on a driving means by means
REFERENCES:
patent: 4465065 (1984-08-01), Gotfried
patent: 4719907 (1988-01-01), Banko et al.
patent: 5152764 (1992-10-01), Goble
patent: 5429641 (1995-07-01), Gotfried
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