Vacuum-operated Acetabular Cup Holder And Positioner

Abstract

A vacuum-operated holding and positioning instrument is provided for use in inserting an acetabular cup during hip surgery. The instrument includes a cup-engaging head, and means for forming at least a partial vacuum between the head and the cup to retain the cup on the head. A suction passage is formed through an instrument tube and handle between a port in the head and a remote suction generator. A thumb-operated suction vent is provided to selectively break the vacuum and deposit the cup at the desired surgical site.

Description

BACKGROUND OF THE INVENTION

The present invention relates generally to surgical instruments, and more particularly concerns a device for holding and positioning an acetabular prosthetic cup during hip surgery.

Hip surgery may include an operation in which a prosthetic cup is affixed in the skeletal acetabulum, and is intended to restore or improve hip joint function. Speaking generally, the operation includes the steps of surgically opening the hip joint, disarticulating the hip, the head of the femur, reaming the acetabulum to a hemisphere, implanting the cup in the reamed acetabular bed and implanting the femoral prosthesis into the femur. Often, the cup and the femoral prostheses are retained in their implanted position by a cementitious substance. When the cup and or femoral prostheses are emplaced, the hip joint is reassembled and the wound closed.

During any such operation, prompt and precise location of the prosthetic cup is required. Implacement of the cup should be made promptly after the surrounding acetabular skeletal material has been prepared, since hemorrhaging may present difficulty during the operation. Moreover, the possibility of infection during such operations encourages their speedy conclusion and wound closure; operating instruments which permit shortening operating time are thus desirable. When emplaced, the prosthetic cup must be precisely located and oriented so that the artificial femoral head can be engaged from a position which will later allow free and natural hip movement by the patient.

Since the necessary surgical incisions are often deep and the cup implacement site may be located at a relatively long distance from the surgical opening, difficulty may be encountered in emplacing the acetabular cup as rapidly and as precisely as possible.

Several surgical instruments have previously been provided for inserting and positioning these acetabular cups in the surgical site. The Charnley and Bechtol devices each depend upon a friction fit between pins extending from the instrument and scallops in the periphery of the cup. The Muller instruments frictionally engage the inner surface of the cup by a mating spherical surface. Other devices, such as the McKee-Farr instruments, also depend upon frictional engagement of the cup upon an instrument head. In using these instruments, difficulties have occasionally been experienced in separating the holding instrument and emplaced cup; these difficulties can result in disturbing the alignment of the cup in the yet unhardened bone cement, and delay in completing the operation. Moreover, frictionally engaging the cup upon its inner, femur-bearing surface can cause scratches or mars which weaken the cup or damage the contracting head of the femoral prosthesis.

Other instruments used in positioning do not hold the cup. Although separation of the instrument from the cup is easy, cup insertion can be awkward, since the cup must be retained, usually by finger pressure, upon the instrument until contact with the cement or acetabular bed is accomplished.

It is the general object of the present invention to provide an instrument for grasping, positioning, and releasing an acetabular cup during hip arthroplasty which permits the cup to be securely grasped, easily and quickly emplaced, precisely located, and gently released without disturbing the cup alignment.

More specifically, it is an object of the invention to provide a cup holding and emplacing instrument which does not depend upon frictional inter-engagement between cup and instrument for retention of the cup upon the instrument.

It is another object of the invention to provide a cup holding and emplacing instrument in which the cup-engaging parts need not be mechanically moved or otherwise altered to release the cup.

It is another object of the invention to provide an acetabular cup holder and emplacing instrument which does not frictionally engage the cup, thereby preventing accidentally marring the cup on any surface.

Other objects and advantages of the invention will become apparent upon reading the following detailed description and upon reference to the drawings. Throughout the drawings, like reference numerals refer to like parts.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an overall elevational view showing the novel cup holding and positioning instrument in its general aspect;

FIG. 2 is a larger elevational view in partial section showing in further detail the various parts of the novel instrument;

FIG. 3 is a fragmentary plan view of the instrument tube showing in further detail a tube vacuum vent; and

FIG. 4 is a sectional view taken substantially in the plane of line 4--4 in FIG. 3 and showing in further detail the vacuum vent.

DETAILED DESCRIPTION

While the invention will be described in connection with a preferred embodiment, it will be understood that it is not intended to limit the invention to that embodiment. On the contrary, it is intended to cover all alternatives, modifications and equivalents as may be included within the spirit and scope of the invention.

Turning to the drawings, there is shown a preferred embodiment of the present novel cup holding and positioning device 10. The device includes a head member 11 having a distal tip portion 12 contoured to mate with the interior surface of an acetabular cup (not shown). A surrounding flange 13 provides a planar surface 14 to precisely locate the cup upon the head 11.

In accordance with the invention, the available aspirant suction present in medical operating rooms is utilized to hold an acetabular cup in its precisely pre-determined position upon the head 11. This is accomplished by forming at least a partial atmospheric vacuum between the instrument head 11 and the cup, and to this end, the vacuum is formed by exhausting atmosphere through a vacuum port 15 formed in the head 11. To enhance the effectiveness of the vacuum seal between the distal tip 12 of the head 11 and the cup, a resilient O-ring 16, which may be made of rubber, is mounted within a retaining groove 17 formed upon the tip 12. The O-ring 16 is positioned so as not to interfere with removal of the cup.

Since, as explained above, hip surgery may require deep incisions, an instrument handle 20 is connected to the head 11 by means of an elongated tube member 21. This tube member 21 may be of any convenient length; in the preferred embodiment, the tube is of some 8 inches in extent.

In carrying out the invention, a fluid pathway is provided between the suction port 15 formed in the head 11 and a remote suction means (not shown). In the embodiment illustrated, the pathway includes a fluid passageway 24 formed in the tube 21 and a communicating passageway 25 formed in the handle 20. Inter-connection of the handle passageway 25 with a flexible vacuum tube 27 is accomplished by a hose barb 28.

To further assist in rapidly and accurately positioning the acetabular cup during surgery, an additional pusher arm 30 is included. In the illustrated embodiment, this arm 30 includes a pusher rod 31 and a second handle 32. To encourage deftness in handling the instrument and to minimize fabrication costs, the arm 30 in the preferred embodiment is separate from but engages the instrument head 11, which is adapted to receive the end of pusher rod 31. Alternatively, arm 30 may be attached directly to the instrument head 11.

In accordance with another aspect of the invention, the cup, once emplaced, can be easily and quickly released from the instrument without disturbing its alignment. This is accomplished by breaking or venting the cup-retaining vacuum at a point between the suction port 15 and the remote suction generating means. In the illustrated embodiment, a suction venting device 34 includes a short stem 35 having a passageway 36 which communicates with the fluid path 24 formed in the tube 21. The extremity of the stem 35 is formed with a seating surface 37 formed to accommodate a valve ball 38. This ball 38 is mounted upon a valve lever 39 by a retaining collar or embossment 40. A set screw member 43 is included to permit insertion or replacement of the ball 38 in the valve lever 39, and to retain the ball within the lever. The lever is biased, as by a small spring 44, for rotation about a pivot pin 45, toward the stem 35, thus urging the ball 38 into its seat 37 in a normally closed configuration. If desired, an off-on vacuum valve can be interposed between the suction means and the instrument handle 20.

In operation, the acetabular cup is placed over the distal end 12 of the head member 11, and is retained thereon by suction applied to the port 15 through the flexible tube 27 and the fluid passageways 24 and 25. The surgeon then grasps the instrument by its handles 20 and 32. By appropriate manipulation, the acetabular cup is emplaced in its bed and is precisely located in the desired position. Actuation of the thumb portion 46 of the valve lever 39 breaks the vacuum and permits the head member 11 to be removed from the cup, and the instrument extracted from the surgical site, without disturbing the cup position.

Claims

The invention is claimed as follows:

1. In an instrument for holding and positioning an acetabular cup during anthroplastic surgery, the improvement comprising a head member having a distal tip portion contoured to mate with the interior surface of said cup and a flange extending radially therefrom, said flange having a planar surface to locate said cup upon said head member, a resilient member mounted on said tip for forming a seal of at least partial air-tightness with the surface of the cup interior and vacuum-forming means including means forming a fluid pathway between a vacuum port formed in said head member and remote suction means for forming at least a partial atmospheric vacuum between said head member and said cup.

2. A device according to claim 1 including selectively operable venting means communicating with said fluid pathway means for selectively breaking said vacuum between said tip and said cup, thereby permitting said cup to be selectively released from said instrument.

3. A device according to claim 2 wherein said suction vent means includes valve seat means and a ball valve member positioned for engagement with said valve seat means to seal said valve seat means and said vacuum forming means from communication with outside atmosphere, and lever means for selectively moving said ball valve member to and from engagement with said valve seat means.

4. A device according to claim 3 wherein said ball valve member is resiliently urged toward said ball valve seat means, thereby positioning said valve means in a normally closed configuration.

5. A device according to claim 4 wherein said lever means includes retaining means for engaging said ball valve member and pulling said ball valve member away from said ball seat means when said lever means is selectively actuated.

6. A device according to claim 1 wherein said means forming a fluid pathway includes a tube member, a handle member, and a hose barb member, said members having inter-communicating hollow passageways formed therein for operably connecting said vacuum port in said head member with said remote suction means.

7. An instrument according to claim 1 including pusher arm means engaging said instrument to provide additional manual grasping means for assisting in locating and inserting said acetabular cup during said surgery.

8. A device according to claim 7 wherein said pusher means includes a pusher rod member engaging said head member, and a second handle member connected to the free end of said rod member.