GB2080113A

GB2080113A - Surgical tool

Info

Publication number: GB2080113A
Application number: GB8022737A
Authority: GB
Original assignee: Individual
Current assignee: Individual
Priority date: 1980-07-11
Filing date: 1980-07-11
Publication date: 1982-02-03
Also published as: GB2080113B

Abstract

A horizontal retractor for use in the insertion or replacement of an artificial hip joint comprises a pair of arms 1 and 2. These arms are pivotally connected together at 3 and have forked sections 4 and 5 connected to their ends on one side of the pivot 3 and are connected together by a mechanism on the other side of the pivot 3. The mechanism comprises a central shaft 10 having screw-threaded portions 11 and 12 extending through respective complementary internally screw-threaded pivots 14 and 15 connecting the shaft 10 to respective arms 1 and 2. This mechanism enables a considerable controlled force to be applied by the surgeon between the femur and acetabulum of the joint after dislocation of the joint to separate femur and acetabulum and subsequent insertion of the forked sections 4 and 5 into the joint. This in turn facilitates the surgeon's task and promotes the carrying out of the operation with an appropriate degree of sensitivity. Various accessories are provided for attachment to the forked sections 4 and 5. <IMAGE>

Description

SPECIFICATION Surgical tool The present invention relates to a surgical tool. The tool is particularly intended for use in operations for the insertion or replacement or renewal of artificial hip joint parts. Examples of such parts are described in my copending U.K. patent application No.

8005254 filed 15th February 1980, and No.

80221 36 filed 5th July 1980.

Application No. 8005254 describes a femural endoprosthesis and Application No.

8022136 describes an acetabular cup into which the head of the prosthesis fits to produce the ball and socket of an artificial hip joint. In the insertion or replacement of such a joint, the existing hip joint is dislocated to remove the head of the femur from the acetabulum. To allow the operating surgeon access to the head of the femur and the acetabulum, these two joint parts are forced apart by means of a horizontal retractor. Existing horizontal retractors are difficult to use and require considerable physical effort by the surgeon. Delicacy of touch is also important and it can be difficult to maintain the required standards in this direction at the levels of force which are often required. One such existing retractor comprises a pair of hinged arms.The ends of the arms at one end of the retractor are sperially formed for insertion into the joint parts and the other ends of the arms are formed with loops into which the thumb and index finger of the surgeon are respectively inserted to use the tool. Overall therefor the retractor resembles a pair of scissors, and in operation the working stroke involves bringing the loops together. This, as indicated above, can be difficult to achieve with the required amount of sensitivity.

According to the present invention, there is provided a surgical tool for use in the replacement or renewal of artificial joint parts comprising two arms pivotally connected together at a point intermediate their ends, the arms being connected together at one end by means of a mechanism which enables the arms to be pivoted with respect to another in a controlled manner, and the force required of the surgeon to produce distraction of the hip joint surfaces to be reduced.

A preferred embodiment of the invention may comprise any one or more of the following preferred features.

(a) The mechanism comprises a shaft having two oppositely screwthreaded portions to which the arms are respectively pivotally connected.

(b) The pivotal connection of each arm of (a) is through a respective internally screwthreaded pivot, (c) The pivots of (b) are located in respective yokes formed in respective arms, (d) The shaft of (a) is provided with an operating knob, (e) A stop is disposed between the screwthreaded portions of (a), (f) The end of the arms remote from the mechanism are specially formed, (g) The special formation of (f) are forks, (h) An accessory is provided for fitting to the forks of (9), (i) The accessory of (h) is an obturator retractor comprising an apertured flat plate, (j) The accessory of (h) comprises an apertured pin, (k) The surgical tool is a horizontal retractor.

In order that the invention may be more clearly understood, one embodiment of the invention will now be described, by way of example, with reference to the accompanying drawings in which: Figure 1 shows a plan view of a complete horizontal retractor, Figures 2 to 5 respectively show sectional views taken along the section lines A-A, B-B, C-C, and D-D on Fig. 1, Figures 6 and 7 respectively show side elevational views of parts of the retractor shown in Fig. 1, Figure 8 shows a diagrammatic view illustrating how the retractor might be used in practice, Figure 9 shows one possible accessory for use with the retractor of Fig. 1, and Figure 10 shows another possible accessory for use with the retractor of Fig. 1, Referring to Figs. 1 to 5 of the drawings, the horizontal retractor comprises two arms 1 and 2 pivotally connected together at 3.Two forked end sections 4 and 5 are respectively pivotally connected at 6 and 7 to one end of respective arms 1 and 2. As can be seen from Figs. 6 and 7, these forked end sections are L-shaped in side elevation and, when pivoted upwards through 90 , the fork, which constitutes one arm of the corresponding L, extends substantially vertically upwards from the plane in which the body of the arms 1 and 2 lies.

The other end of the arms 1 and 2 are provided with a mechanism which enables these ends to be pulled together or pushed apart. The mechanism comprises a central shaft 10 having two oppositely screwthreaded portions 11 and 12 separated by a centrally disposed stop 13. The screwthreaded portions 11 and 12 extend through respective complementary internally screwthreaded pivots 14 and 15 through which the ends of respective arms 1 and 2 are pivotally connected to the shaft 10. For this purpose, the end of each arm is formed with a yoke 16, 17 and the upper and lower arms of each yoke are apertured to accommodate the respective pivots 14 and 15. One end of the shaft 10 carries a knurled knob 18 and the other end a stop 19.

Accessories are advantageously to facilitate the use of the retractor described above. Two such accessories are illustrated in Figs. 9 and 10. Fig. 9 shows an obturator retractor. This is a flat plate 20 which defines a series of apertures 21 along its length to receive one of the forked ends of the horizontal retractor.

Fig. 10 shows a pin 22 which is apertured at 23 to receive one of the forked ends of the horizontal retractor. The pin can be driven into a selected joint area to provide a better grip for the horizontal retractor.

Referring to Fig. 8, in use, after dislocating the hip joint to remove the head of the femur 30 from the acetabulum 31, the pin of Fig.

10 is driven into the area 32 surrounding the acetabulum. The obturator retractor is placed over the head of the femur 30 and the horizontal retractor is inserted with the forked ends 4 and 5 in the positions shown in Fig. 1 so that one forked end engages appropriate apertures 21 of the retractor 20 and the other formed end engages the aperture 23 of the pin 22. The horizontal retractor is then pushed so that the forked ends 4 and 5 adopt the position shown in Fig. 6 and 7 respectively and the knurled knob 18 turned to bring the yokes 16 and 17 closer together and push the ends 4 and 5 further apart, thus opening up the joint areas to the surgeon.

It will be appreciated that all parts described are made of appropriate surgical material such as stainless steel. It will also be appreciated that the above embodiments have been described by way of example only and that many variations are possible without departing from the scope of the invention

Claims

claimed. CLAIMS

1. A surgical tool for use in the replacement or renewal of artificial joint parts comprising two arms pivotally connected together at a point intermediate their ends, the arms being connected together at one end by means of a mechanism which enables the arms to be pivoted with respect to another in a controlled manner, and the force required of the surgeon to produce distraction of the hip joint surfaces to be reduced.

2. A surgical tool as claimed in claim 1, in which the mechanism comprises a shaft having two oppositely screw-threaded portions to which the arms are respectively pivotally connected.

3. A surgical tool as claimed in claim 2, in which the pivotal connection of each arm is through a respective internally screw-threaded pivot.

4. A surgical tool as claimed in claim 3, in which the pivots are located in respective yokes formed in respective arms.

5. A surgical tool as claimed in claim 2, 3 or 4, in which the shaft is provided with an operating knob.

6. A surgical tool as claimed in claim 2, 3, 4 or 5, in which a stop is disposed between the screw-threaded portions.

7. A surgical tool as claimed in any preceding claim, in which the ends of the arms remote from the mechanism are specially formed.

8. A surgical tool as claimed in claim 7, in which the ends of the arms are forked.

9. A surgical tool as claimed in claim 8, in which an accessory is provided for fitting to the forked arms.

10. A surgical tool as claimed in claim 9, - in which the accessory is an obturator retractor comprising an apertured flat plate.

11. A surgical tool as claimed in claim 9, in which the accessory comprises an apertured pin.

12. A surgical tool as claimed in any preceding claim, which is a horizontal retractor.

1 3. A surgical tool for use in the replacement or renewal of artificial joint parts substantially as hereinbefore described with reference to Figs. 1 to 8 with or without the accessory illustrated in Figs. 9 or 10 of the accompanying drawings.