DE102007025242B4 - Surgical instrument - Google Patents

Abstract

Surgical instrument with an outer tube (1) in which an inner tube (2) is rotatably mounted, which is provided at its free end with a tool which comprises a milling head (3) which is fastened to the inner tube (2) characterized in that the end region of the tool facing away from the milling head (3) is designed with a larger diameter than the inner tube (2) and, due to the larger diameter, forms a sliding bearing surface (5) for contact with an inner surface of the outer tube (1).

Description

The invention relates to a surgical instrument according to the preamble of claim 1.

In detail, the invention relates to a surgical instrument having an outer tube in which an inner tube is rotatably mounted, which is provided at its free end with a tool.

Such instruments are also referred to as so-called shaver blades. The prior art is exemplified in the EP 1 006 898 B1 directed.

The outer tube is rotatably mounted on a drive means of a coupling means while the inner tube with a relatively high speed of up to 12,000 rpm is rotated ^-1. Shaver blades of this kind are used, for example, in arthroscopy in order to remove tissue invasively and to suction it through the inner tube.

It is known from the prior art that the inner tube rotates with play in the outer tube. This results in an inaccurate in terms of fits sliding bearing, which leads to increased wear and resistance moments.

From the prior art it is known to postpone or shrink additional slide bearings on the inner tube. Such annular bushes may for example also consist of a different material, such as the inner tube. Apart from the resulting from the complicated production costs, these solutions have the disadvantage that can accumulate in the joints occurring germs, impurities or the like, so that the required cleaning or sterilization is not or only to a limited extent possible.

From the DE 697 32 580 C2 For example, a surgical instrument is known in which the distal end region of the inner tube is widened and forms a slide bearing. In the expanded distal end portion of a shaft end of the tool is joined. In this construction, there is no possibility of an exact design of the plain bearing and thus not the possibility of an exact bearing guide, as a mechanical revision of the outer surface of the inner tube is not possible.

The US 3,976,077 A shows a surgical instrument with a double-walled outer tube, in which by means of plain bearing bushes a tool is guided. The drill-like head of the tool and the adjacent area have an equal diameter.

From the US Pat. No. 7,077,845 B2 another surgical instrument is known, which is provided with an outer tube, at the open end portion of which a head provided with abrasive particles is mounted, which has a diameter different from a bearing region of the tool.

The invention has for its object to provide a surgical instrument of the type mentioned above, which avoids the disadvantages of the prior art with a simple structure and simple, cost manufacturability and allows safe storage, especially in design of the tool with a milling head.

According to the invention the object is achieved by the combination of features of claim 1, the dependent claims show further advantageous embodiments of the invention.

According to the invention it is thus provided that the milling head is fixed to the inner tube, wherein the milling head is provided at its end remote from the toothing having a larger diameter than the diameter of the inner tube. Thus, the enlarged diameter diameter portion of the milling head comes into abutment with the inner wall of the outer tube, while the inner tube itself is securely guided with a constant gap or distance in the outer tube. This results in an effective slide bearing.

According to the invention it is particularly advantageous that no additional components or components must be used to form the sliding bearing. Rather, the thickened in diameter portion of the milling head forms part of the sliding bearing.

It is understood that the end portion of the milling head formed larger in diameter with respect to its axial position, its axial dimensioning and its configuration can be adapted to the particular circumstances.

The sliding bearing surface formed by the enlarged in diameter portion of the milling head sliding surface can be made according to the invention of the same material as the inner tube.

According to the invention, the sliding bearing surface of the area thickened in diameter can also be provided with a different material, which is applied, for example, in the form of a coating. Since, according to the invention, only a relatively small increase in diameter is required in order to realize a bearing of the front region of the inner tube in the outer tube, the sliding bearing surface can be formed, for example, by an electrolytically applied coating or the like.

In the following the invention will be described by means of an embodiment in conjunction with the drawing. Showing:

1 a schematic, shortened in length side view of an embodiment of the surgical instrument according to the invention, and

2 an enlarged detail view, partly in section, of the distal end portion of the surgical instrument according to 1 ,

The surgical instrument according to 1 includes an outer tube 1 in which rotatably an inner tube 2 is stored. With regard to the storage and the connection with a drive unit, reference may be made to the prior art, so that detailed descriptions are not required at this point.

As can be seen from the presentation of 2 gives, is the front portion of the outer tube 1 beveled or provided with an opening, so that one at the distal end of the inner tube 2 mounted milling head can be brought into use.

The outer tube 1 can be 150 mm long, for example.

The milling head 3 is on the inner tube 2 attached, for example, welded.

According to the invention, the milling head has at its to the inner tube 2 adjacent end a slide bearing surface 5 which is formed larger in diameter than the outer diameter of the inner tube 2 so that the plain bearing surface 5 sliding on the inner wall of the outer tube 1 is guided and together with this forms a sliding bearing.

LIST OF REFERENCE NUMBERS

1

outer tube

2

inner tube

3

cutter head

5

friction bearing surface

6

recess

Claims (7)

Surgical instrument with an outer tube ( 1 ), in which rotatably an inner tube ( 2 ) is mounted, which is provided at its free end with a tool which a cutter head ( 3 ), which on the inner tube ( 2 ) Is fixed, characterized in that the (the cutter head 3 ) facing away from the end portion of the tool is formed with a larger diameter than the inner tube ( 2 ) and by the larger diameter a sliding bearing surface ( 5 ) for engagement with an inner surface of the outer tube ( 1 ). Surgical instrument according to claim 1, characterized in that the sliding bearing surface ( 5 ) made of the same material as the milling head ( 4 ) is made. Surgical instrument according to claim 1, characterized in that the sliding bearing surface ( 5 ) made of the same material as the inner tube ( 2 ) is made. Surgical instrument according to claim 1, characterized in that the sliding bearing surface ( 5 ) made of a different material such as the inner tube ( 2 ) is made. Surgical instrument according to claim 4, characterized in that the sliding bearing surface ( 5 ) is provided with a coating. Surgical instrument according to one of claims 1 to 5, characterized in that the cutter head at the distal end formed hollow and with a recess ( 6 ) is provided. Surgical instrument according to one of claims 1 to 6, characterized in that the transition region between the cutter head ( 3 ) and the sliding bearing surface ( 5 ) is formed reduced in diameter.

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