GB2159680A

GB2159680A - Surgical targetting device

Info

Publication number: GB2159680A
Application number: GB08512579A
Authority: GB
Inventors: Omprakash Vashumal Narang
Original assignee: Individual
Current assignee: Individual
Priority date: 1984-05-17
Filing date: 1985-05-17
Publication date: 1985-12-04
Also published as: GB8412652D0; GB8512579D0; GB2159680B

Abstract

A surgical targetting device comprises a clamp having a pair of opposed jaws which are slidable on a threaded rod 5. On one of the jaws there is a plate on which sighting barrels 2, 2' are mounted which extend into the jaws of the clamp. Means 7, 7' are provided for locking each of the jaws at selected positions on the screwed rod. In use the device is clamped to a patient's limb and is viewed through an image intensifier and the sighting barrels are aligned with location apertures in a previously implanted prosthesis. Having aligned the device in this manner the jaws are tightened to impress marks on the patient's skin for surgical incisions to be made. The device is then relocated on the patient's limb and the clamp tightened to force the barrel to penetrate the flesh and provide a means to facilitate insertion of fixation screws. <IMAGE>

Description

SPECIFICATION Surgical targetting device This invention relates to a surgical targetting device for the use in conjunction with an image intensifier to obtain an alignment on a feature located within the body of a patient.

Particularly, but not exclusively, the invention is intended for use on limbs to obtain alignment on apertures in an implanted metallic prosthesis or bone fixation device such as Gross and Kempf nail.

A Gross and Kempf nail is an elongate rod insertable longitudinally into the intramedullary canal of a fractured bone to bridge the fracture. Proximate the distal end of nail there are provided pairs of apertures for fixation of the nail to the bone by transverse screws.

In order to locate the fixation apertures, the patient's limb is viewed on an image intensifier. In the known practice a targetting device is clamped to the framework of the image intensifier or preset and mounted on the proximal end of the nail and is brought into the field of view. The targetting device is of metal and has a through-passsage which can be seen via the image intensifier and brought into alignment with the fixation aperture or apertures of the nail. Once alignment has been achieved, surgical instruments are passed through the through-passage to form an access to the locus of the fixation apertures and the screws are similarly located.

An object of this invention is to provide an improved surgical targetting device.

A surgical targetting device comprising a clamp having a pair of opposed jaws, on one of the jaws a plate, on the plate a tubular barrel extending inwardly through the plate, means for opening and closing the jaws and means for locking the jaws. Preferably the jaws are slidably mounted on a screwed rod and the locking means ae pairs of lock-nuts, one on each side of each of the jaws.

Preferably also the screwed rod has a longitudinal slot co-acting with a keyway in each jaw to prevent twisting of the jaws on the rod.

One of the jaws may have a bifurcated configuration, each bifurcate being a plate which is curved to engage a limb of a patient.

In a preferred form the invention therefore, may comprise a clamping device with a pair of curved plates on one side and a pair of barrels on the opposite side. There may be provision for sliding the plates and the barrels towards or away from one another and locking them in any desired position. The plates and barrels are mounted on a threaded rod allowing only a sliding movement by virtue of its cross section. The means for locking the plates and barrels may comprise a pair of lock nuts located on the threaded rod, one on either side of the assembly carrying plates and barrels. The distance between the plates is more than the corresponding distance between the barrels on the opposite side. This may be made more flexible if the blades of the plates have a provision of sliding towards each other on its own rod and also a provision for locking them in position.Preferably the barrels are spaced in accordance with the spacing of fixation apertures in an implanted device. In the case of Grosse and Kempf nail, there are two barrels on the targetting device corresponding to spaced pair of apertures on the nail.

The device has the flexibility of using different sizes of curved plates to suit the needs of individual patient and also different sizes of barrel assembly to suit the bone through which the screws are inserted. The barrel assembly for Tibia is smaller than that for Femur. The barrels are shorter and smaller in diameter. Other accessories may include centering sleeves with handles. These sleeves are dimensioned to enter the barrel on the device.

The sleeves may be longer than the barrels on the device, used mainly to centralize and stabilize the instruments.

The invention will now be described with reference to the accompanying drawings of which Fig. 1 is a perspective sketch of the device.

Fig. 2 is a cross section of the threaded rod along the line X-X on Fig. 1 showing the sliding mechanism of the plate and barrel.

Fig. 3 is an illustration of the image seen on an image intensifier monitor when the device is in use.

Referring to Fig. 1, the invention is in the form of clamping device having jaws having a pair of curved plates 1 , 1' and a pair of barrels 2,2'. The plates and barrels are mounted on their own rods 3 and 4 respectively. The plate and barrel assembly slide on a threaded rod 5. The threaded rod 5 has a groove 6,6' on each of two smooth side surfaces which cooperate with a slot in the rods 3 and 4. The rods 3 and 4 can therefore slide towards or away from one another yet remaining free from the threaded surface of the rod 5. Fig. 2 illustrates in cross section the mechanism involved.

A pair of knurled locknuts 7,7' on either side of rods 3 and 4 are provided for locking the rods 3 and 4 in any desired position.

Accessories include a centering sleeve 8 with a handle 9. The external diameter of sleeve allows it to be inserted into the barrel and the inside diameter permits insertion of instruments to drill and insert screws. Different sized sleeves may be provided according to the barrel size used.

In use, an implant has already been surgically inserted into the medullary cavity of the patient's bone. The apertures in the implant are visualised on the monitor of the image intensifier as perfect circles. With the help of a sterile pointer the corresponding points on the skin are located. Barrels are centered on these points and the device is clamped into position and locked. The position is confirmed after moving the hands away from the operating area.

Fig. 3 shows generally the view which appears on the screen of the image intensifier.

In Fig. 3, 20 and 21 are X-Ray images of bones, bone 20 having an implanted Gross and Kempf nail 22. The apertures in the nail are visible as perfect circles 23,23'. The circular outline of the barrels 2,2' is superimposed on the image of the apertures 23,23'. When the circular image of the apertures is seen through the superimposed barrels, the device is properly targetted.

The targetting device is now tightened over the patient's limb and then removed leaving impressed marks on the skin. Surgical stab incisions are made across both marks and the device is reapplied in the same position. The device is now tightened causing the barrels 2,2' to penetrate the deep tissues and come into contact with the bone. Once again the position is confirmed on the image intensifier moving the hands away from the operating field. Following this, an appropriate centering sleeve is inserted into the barrel. The sleeve acts as a guide to centralize and stabilize the instruments.

During the process of drilling, the drill end passes through the bone on the outside, through the aperture in the nail and finally through the bone on the opposite side thereby transfixing the implant. The length of the drilled hole is measured with a depth gauge and corresponding screw is inserted. The procedure is similarly carried out for insertion of the second screw. Both screws when tightened fix the nail 22 in position.

The device of this invention thus does not involve modification to suit different models of image intensifiers, nor does it involve manufacturing different extensive nail mounted devices which have to be preset for femoral and tibial nailing.

The device is adaptable with different sized plates and barrels to suit individual needs of the patient, all of which may be supplied in a kit form.

The device may be used in any desired position with patient supine or lateral.

The aligning adjustments are easy and under direct control of the surgeon.

When two screws are to be inserted, further adjustments and exposure to X-Rays is not required during insertion of second screw as is the case in image intensifier mounted device.

The new device is small and simple in its construction and therefore easy to manufa#cture, to sterilize and to use.

Claims

1. A surgical targetting device comprising a clamp having a pair of opposed jaws, on one of the jaws a plate, on the plate a tubular barrel extending inwardly through the plate, means for opening and closing the jaws and means for locking the jaws.

2. A device as claimed in claim 1, in which the jaws are slidably mounted on a screwed rod and the locking means are pairs of lock-nuts, one on each side of each of the jaws.

3. A device as claimed in claim 2, in which the screwed rod has a longitudinal slot co-acting with a keyway in each jaw to prevent twisting of the jaws on the rod.

4. A device as claimed in any preceding claim, in which one of the jaws is a bifurcated member, each bifurcate being a plate which is curved to engage a limb of a patient.

5. A device as claimed in any.preceding claim, in which the free end of the barrel is serrated.

6. A device as claimed in any preceding claim including also a sleeve insertable into and rotatable within the barrel.

7. A limb-mountable surgical targetting device substantially as hereinbefore described with reference to and as illustrated in Figs. 1 and 2 of the drawings.

7. A surgical targetting device substantially as hereinbefore described with reference to and as illustrated in Figs. 1 and 2 of the drawings.

CLAIMS Ammendments to the claims have been filed, and have the following effect:~ Claims 1 and 7 above have been deleted or textually amended.

New or textually amended claims have been filed as follows:~

1. A limb-mountable surgical targetting device comprising a clamp having a pair of opposed jaws, means for opening and closing the jaws, means for locking the jaws, on one of the jaws a plate or a pair of plates for contact with the patient's limb, and on the other jaw a tubular barrel or barrels extending inwardly, providing visualisation through the or each barrel on an image intensifer or a target within the patient's limb and allowing centralisation and stabilisation of instruments inserted through the or each barrel and terminating in an edge for impressing a mark on the patient's skin and penetrating deep tissues.