The present invention relates to surgical instruments, more specifically to a cutting instrument for uterocervical conisation.

In diagnosis and treatment in cervical pathology it is a standard medical procedure to remove a small portion of the cervix uteri. The surgical operation is designated conisation, and earlier has usually been carried out with the aid of a scalpel. This is a troublesome and time-consuming operation requiring anesthesia and which can cause extensive bleeding and discomfort for the patient.

Modern laser technology has made it possible to perform conisation without using instruments requiring contact with tissue. The laser technique reduces patient trauma during the operation and simplifies the surgical procedure in conisation. An example of the equipment for this technique is described in the patent specification US-3 804 095.

Another method in the art of conisation is based on chilling the tissue to be operated on.

Uterocervical conisation with the use of diathermic equipment is also known to the art. Here one can use equipment including a handle in the form of a pistol grip, which is implemented such that when the trigger of the piston grip is squeezed, this movement is translated into a rotational movement with the aid of a mechanism in the pistol grip. In turn, this rotational movement is transferred to a holder for a diathermic wire, the wire forming an angle to the longitudinal axis of the instrument, so that when the holder is turned one revolution a cone is cut out by the diathermic wire. This can be done very rapidly, within the space of about 30 seconds, and as with laser technique, the patient's trauma is reduced to a minimum, and bleeding does not take place. Furthermore, it is often sufficient with a local anesthetic Known

instrumens intended for diathermic uterocervical conisation include a set of different holders, the angle of the diathermic wire being fixed. This means that wire holders have to be changed from patient to patient, depending on the size of the deceased tissue portion which is to be removed. It is thus necessary to keep a relatively large set of different holders in stock.

The object of the present invention is to afford an ins-trument for uterocervical conisation with a facility for changing the angle of the diathermic wire, and thus the size of the portion which is to be cut out. This means that in principle it is only necessary to stock one size of the instrument in question. By the facility of being able to change the angle of the wire, the instrument can be adjusted to the shape of the deceased portion during the operation also, so that the least possible amount of tissue is removed.

This object is achieved with an instrument in accordance with the invention as defined in the appended claims.

The invention will now be described in detail with reference to the accompanying drawings , on which

Figure 1 is a side view of the instrument in accordance with the invention,

Figure 2 is a view from below of the instrument, and

Figure 3 is a longitudinal section for the instrument.

A holder member 1 is illustrated in Figure 1, and includes a shank portion 2 and an insertion end 3. A contact rod 7 is inserted in the shank portion 2. This rod is electrically connected via a pistol grip (not illustrated) to the diathermic apparatus. A diathermic wire 6 is electrically connected to the contact rod 7 inside the shank 2. The other end of the wire 6 is attached to the tip of the insertion end

3. The shank 2 has a larger diameter than the insertion part, which has a diameter attaining to about 6-10 mm. There is a portion 11 between the shank 2 and the insertion part 3, this portion having a diameter lying between those of both these parts. On this intermediate portion 11 there is a member formed as a sleeve, which is mounted on this intermediate portion 11, and is glidably movable along it, an alternative position being illustrated in dashed outline. There is a guide groove 9 made in the portion 11. On its inside the sleeve 10 is provided with a guide pin 12, which is accommodated in the guide groove 9. The friction between the sleeve 10 and the intermediate portion 11 is of a magnitude such that the sleeve can be moved backwards and forwards along the portion 11 with a certain amount of resistance.

From its attachment point in the insertion end 3, and while forming an angle & to the longitudinal direction of the instrument, the diathermic wire 6 extends up to the outer end of a portion 5 projecting from the sleeve 10, and over this end back to the rod 7. The projecting portion 5 is provided with a groove in which the wire is accommodated.

By moving the sleeve along the portion 11 the angle 0^ is altered, and thus also the height and base of the cone formed when the instrument is turned a complete revolution. Due to the friction between the sleeve and the portion 11, the angle C will remain fixed during the operation, but with a simple hand movement it can be altered, if this should be required, even during the operation. Not only the angle ( is altered by moving the sleeve 10, but the length of the wire as well, and this must be compensated, which is achieved by a spring 8 disposed between the diathermic wire and the attachment point in the contact rod 7.

The holder member 1 is thus mounted in a commercially available pistol grip, the functin of which is to translate the movement of the trigger to a rotational movement. The contact rod 7 is then locked by a locking means in the pistol

grip, which simultaneously constitutes electrical contact means. The pistol grip is connected to a dithermic apparatus of standard type, and the other pole is obtained by a large metal plate being placed against the patient's back, this plate being grounded.

The sleeve 4 is provided with small indentations on the sides to facilitate gripping the sleeve by the surgeon for moving it from its position. The sleeve 4 may also be provided with a locking means for fixing its position, as an alternative to being fixed by friction.

The conisation instrument in accordance with the present invention thus has the advantage that it is not necessary to have a large collection of different instruments for different sizes of damage and in itself the instrument can be adjusted to the size of the tumour present. Furthermore, the instrument is flexible, in as far as the surgeon can change the angle of the wire during the operation if he were to discover that damage is asymmetric. This means that he does not need to cut away healthy tissue unnecessarily, to be sure of cutting away all deceased tissue.