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Archive for the ‘Forceps’ Category

Forceps

There are a lot of different types of forceps, they are used for gripping, pulling, dissecting and many other things, it is important that they grip well along the whole length of the jaws, and that if they have serration’s on them that they are in good shape.

With the type that are held like a pair of scissors, a common complaint is that they are loose, tightening them is the same procedure as for tightening a pair of scissors.

Some forceps, and for that matter scissors, have tungsten carbide inserts in them to make them last longer, they shouldn’t (as scissors) need sharpening that often, but when you do you should use a green grit grinding wheel.

Remember one thing, tungsten carbide is very brittle, do not try to bend it as you would a steel instrument.

You are able to get new tungsten carbide inserts from some places, but on the whole you will find this difficult, however if you do the old ones can be taken out with oxyacetylene heat, and the new ones silver brazed in.

The type of forceps that is held between the fingers, some of which are called dissecting forceps, some times come to you with the complaint that they are crossing over, what they mean is the tips slip across each other when the user tries to grip something, the reason for this is often that the surgeon or whoever is using them is either not holding them properly or that he is using a pair that is to small for the job, sometimes it is the fault of the instrument but you can quickly see this by bringing the two tips together, they should meet absolutely together and flat against each other, you should be able to grip a thin piece of paper right at the tip. Close them up and look very closely at the end with a watchmakers eyeglass. Sometimes when you look at them they may look as if they are meeting correctly along their length but when you look at the tip you might find they are not meeting. Here you will have to bend them very gently with a pair of small pliers. If you bent too much you will end up with them not meeting a little further along.
If one of the tips is twisted or is bent and not lined up correctly then they will cross over, careful bending with your fingers, with a pair of pliers or in a vice will cure that. The advice is to be very gentle and do it with little steps.
If there is nothing wrong with the forceps, you have two options.

a. Tell the surgeon that there is nothing wrong with them, and give him a demonstration of how they should be used or advise him to use a different pair.

b. fit an anti-cross over pin.

On the whole plan B may be the easier, most surgeons do not take kindly to instruction from a technician, though skilfully and tactfully done you may get away with it.

Should you decide not to lecture the surgeon here is how to fit an anti-cross over pin. This is a pin that you put inside one side of the forceps then goes through a hole in the other side and when the forceps are closed stops it crossing over.

a. Select a point on the forceps where the finger grips are, and at the mid-point put a small mark, this is where the pin will go.

b. Now find yourself a small round piece of stainless steel, about 10 mm. long and about 1 mm. in diameter.

c. File or grind a taper on to it but leave the end rounded, clean it up to get rid of all the grinding or file marks, and lastly polish it.

d. Drill a hole at the previously selected point that is just large enough so that the pin will be a good tight fit in it and continue through the other half so that you know that the holes line up.  Countersink the hole that the pin is to be brazed into on the outside.

e. Tap the pin into place, make it long enough so that when the forceps are closed the pin will just go through the other side.  The tapered end of the pin should be on the inside.

f. When you are happy with the length, cut off the excess and file it flush with the body of the forceps.

If you have the equipment you should now silver braze the pin in to place on the outside so that the braze flow neatly into the countersink you made earlier.  It is quite important that you do this, even if your pin is a very tight fit there is the risk that it could fall out inside a patient, surgeons are not very keen on this as it means that in theory they should open the patient up again and look for it.

g. Now drill the hole in the other side of the forceps very slightly larger so that the pin will go through it when it is closed up. Be careful to use the right sized drill because the hole must only be very slightly larger than the pin otherwise it will not do its job. Remove any sharp edges and polish the whole instrument.

h. Test the operation of your new pin, make sure that it does not bind in the hole if it does your hole is either not quite in the right place or not quite large enough.

i. Make sure that the pin is not sticking out too far and is not sharp.

The surgeon will not be pleased if your new pin punctures his gloves during the operations.

Instruments such as forceps some times crack at the joints, for there is a good deal of strain at this point, the complaint will be that they are not holding, it is possible to silver solder them at the crack if you are very careful, the trouble is that the soldered joint is never really strong and might crack again at the wrong moment, so unless you HAVE to its better not to try to do it.

The last job on just about any instrument you have been asked to look at is to polish it. If you have one, use a powered buffing wheel and stainless steel polish.                                                                                                                                                         Just a gentle polish to put a shine on it, even if you have not had to do anything, sending them back with a nice shine looks as if you have done something. Pride in the job.

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