BASIC PLASTERCRAFT

For all slabs and casts, get everything ready before you wet the plaster bandages. So put stockinette on the limb, or cut and roll a layer of cotton wool directly on to the skin. Fold and trim the slab, and have your assistant ready.

Use 15 or 20 cm bandages wherever possible. Cold water is usually best, but hot water makes them set faster, so adjust the temperature to your needs.

SLABS

Take a dry bandage of suitable width, and use its loose end to measure the required length of the slab. Lay this length of bandage on a table and then double more bandage backwards and forwards over it until you have enough layers to make a slab of the right thickness. Usually, 5 to 10 layers are enough. If necessary, fold the bandage double.

Hold the dry slab in both hands, and dip it in water. Wait for the bubbles to stop, remove it, gently squeeze it, and quickly smooth it out on a flat surface. This will remove the bubbles from between the layers of bandage, and prevent them separating later to weaken the cast.

Apply the wet plaster slab to a single layer of cotton wool, or to a tube of stockinette. Hold the patient’s limb in the correct position and smooth out the slab.

CAUTION! Don’t let a plaster slab cover more than two thirds of the circumference of a limb, or it will become so nearly a circular cast that it may obstruct his circulation.

CIRCULAR CASTS

Pad the patient’s bony points with particular care in all casts, as in Fig. 70-2, especially if he is thin. Be sure to pad well around his knee and his heel. Then pad the rest of his limb.

If you are fortunate enough to have tubular stockinette, thread this over his limb, leaving it long enough to extend several centimetres above and below the cast. If necessary, cut a hole for his thumb. if you have no stockinette, wind ordinary cotton bandages on to his limb.

Use special orthopaedic padding, or ordinary cotton wool expanded as in Section 70.1. Roll this smoothly over his whole limb, evenly with no folds or lumps, and without obscuring the shape of the limb. Don’t pull it tight or it will tear. You may need 2 or 3 layers to build up a thickness of about 1 cm. Put extra padding over bony prominences. Apply it from well above to well below where the cast will end.

CAUTION! (1) Don’t apply so much padding that the patient’s limb is able to move about freely inside the cast, as if it were inside a boot. (2) if there is a wound on his limb, put the padding on loosely, it may become wet with blood, contract, and impede the circulation.

Roll on the wet plaster bandage without lifting it off his limb, pressing each fold firmly with the base of your thumb, so that most of the tension is transmitted to the middle of the bandage, and not to its edges, where it might cause a sharp ridge. The tension you need will vary with the thickness and elasticity of the padding.

CAUTION! (1) The correct tension is important or the cast will be loose. (2) The inside of the finished cast must be smooth, because ridges may cause sores. (3) Never pull a plaster bandage tight.

Apply each turn slowly, settle it carefully in position, and join it to the turn below by smoothing it with your hands to remove bubbles. Let it follow the way it wants to go. Leave about 3 cm between turns. Apply it as a spiral without reverses, and when you have to change its direction, make a quick tuck, and smooth it out. Don’t twist the whole bandage, or attempt ’figures–of–eight, or apply two turns in exactly the same place, except at the ends.

While you are applying one roll of plaster, ask your assistant to wet the next one. Bandage from one end to the other, and back again, making the cast slightly thicker at its ends, where it will be most likely to fray. Don’t build up its thickness over the fracture site, where extra thickness will be useless.

Trim its edges while they are still wet, not after they have dried. Bind the ends of the stockinette over into the cast with the last few turns of bandage. This will make it smooth and strong.

CAUTION! (1) Don’t press on a cast with your fingers or thumb while it is hardening, or they will leave a swelling inside it which will cause a pressure sore. (2) For the same reason don’t let a cast, especially a cast over the heel, rest on a hard surface while it sets.

A large cast may not be completely dry for 72 hours, and will not be fully strong until then.

Alternatively, start by placing a slab of 4 thicknesses of bandage each side of the limb to strengthen it. Or, incorporate such a slab between layers of bandage.

If you want to strengthen a cast, let the cast dry thoroughly over the next day or two, then add morte plaster. Wet plaster bandages stick to dry plaster better than they do to damp plaster.

SPLITTING A CAST

The cast must be padded, or you will cut the patient as you try to split it!

INDICATIONS (1) All casts put on under emergency conditions. (2) A cast on a patient who is going on a journey. (3) Casts over any recent injury, whether swollen or not. The patient’s limb may not be swollen now, but it may soon start to swell. (4) All first casts on tibia fractures. (5) You will be wise if you split all first circular casts, especially if nursing care is not good.

CAUTION! Failure to split a cast is a common cause of disaster.

SPLITTING A CAST There are several ways to split a cast, but the secret is to split it while it is still soft 3 or 4 minutes after you have applied it.

(1) If the cast is still fairly soft, use a disposable scalpel blade to make a single cut through the plaster down to the padding. if it is already hard, use a sharp plaster knife, a solid bladed scalpel, or a pen knife. This will be hard work. When the cast is hard, widen the split a little with a screwdriver or a plaster spreader.

(2) Cutting a hardened cast will be easier if you start the cut with a knife, then wet it with an eye dropper, either with water, or with dilute acetic acid (vinegar). Let the plaster under part of the slit soften while you work on another part. Then return to the first part. This is particularly useful for removing casts from small children.

(3) Lay a rubber strip (such as a piece of car inner tube) on the skin where you intend to cut before you apply the cast. Then cut through it down to the strip.

(4) Lay a piece of greasy rubber tube about the thickness of your finger on the skin where you are going to split the cast. Pull the tube out before you split it. The cast will be thinner where the tube was and will split more easily.

SITES FOR SPLITTING OR REMOVAL Avoid the bony points, so cut an arm cast down the midline of its anterior surface. If there are anterior and posterior slabs, avoid them and slit the cast down its ulnar side. Split a leg cast down its lateral surface, cutting between the lateral malleolus and the heel.

BIVALVING A CAST Cut the cast right down to the skin, on both sides of the limb.

CARING FOR A CAST if the patient has to walk home in the rain, let his cast dry and then give it a coat of oil paint.

Lice and other insects may multiply under a cast, and cause such intolerable itching that they drive him to remove it piece by piece. If necessary, dust some insecticide powder down the ends of his cast.

Casts often become loose in time, so see him regularly, and repair and replace his cast as necessary.

AN EXPLANATION TO THE PATIENT FOR ALL CASTS

Explain why you are applying the cast, and when you expect to remove it.

Tell the patient not to use his limb or bear weight on his leg for 48 hours while his cast dries out. Warn him to raise it to prevent swelling, to keep it dry, and to return immediately if he has pain, numbness, stiffness, or if his fingers or toes become cold, blue, or swollen. He must also return if his cast becomes loose. Explain that he must exercise his muscles inside the cast, and the joints which are not immobilized, especially his fingers and toes. He must understand these instructions, so if you cannot speak his language, find someone who does. If he can read, hand him a sheet telling him what to do.

CAUTION! If he comes back complaining of the above symptoms, take his complaint seriously.

REMOVING A CAST can be more painful than applying it, so look at the patient’s face to see if you are hurting him. Let him see what you are doing, and let him help, where he can.

Snip the stockinette at the end of the cast and insert the blade of the shears between the stockinette and the cast. Keep the blade parallel to his skin, and avoid bony prominences. Alternatively, and especially in small children, soak the cast off in water. A mother can do this when her child’s fracture has healed, or if he has a club foot.

CAUTION! Use an electric plaster cutter only if: (1) You are sure there is padding under the whole length of the cut. (2) The patient is conscious. Use an up and down movement, and don’t try to slide the blade of the cutter along his limb.

DIFFFICULTIES WITH CASTS

If your PLASTER BANDAGES ARE UNSATISFACTORY, use them with hotter water, make the cast thicker, and collect any loose powder that falls off, moisten it with a little water, make it into a paste, and rub it on to the outside of the cast. Use it on the less critical fractures, and keep your best plaster for malleolar fractures, and difficult forearm fractures.

If PLASTER BANDAGES ARE SCARCE, you may be able to economize in their use by making casts lighter, and strengthening them with strips of wood, bamboo, or tin. There are alternative methods for some fractures which do not require plaster, as described below.

Cut the bamboo into strips 300103 mm. Wind a thin initial layer of plaster bandage round the limb. Then apply the bamboo strips all round, especially across the joints. Finally, apply a second thin layer of plaster to complete the cast.

If a CAST BECOMES LOOSE and plaster is scarce, cut a longitudinal strip out of it and then bind it together.

If you have NO PLASTER, you may be able to use strips of bamboo. Many traditional bone setters used strips of bamboo very effectively. Tie these over a well wrapped or padded limb, and hold them in place with string, or adhesive strapping, as in the next section. The traditional method of applying wet goatskin is dangerous, because it contracts as it drys and can cause Volkmann’s contracture.

Fractures of the tibia have been treated by wrapping layers of cardboard round a leg.

If you suspect even the possibility of ISCHAEMIA, immediately split the patient’s cast from end to end. if this does not cure his symptoms, remove it and examine it for signs of the compartment syndrome which may need incision (70.4). Loss of reduction is better than Volkmann’s ischaemic contracture, or gangrene.

If a patient has a PRESSURE SORE on his heel, fish mouth his cast, and then repair it, as in A, Fig. 70-7. If he is in bed, with his cast removed, put a big sausage shaped dressing round his ankle, so that it raises the sore from his bed.

NEVER SEND A PATIENT IN A CAST HOME WITHOUT EXPLAINING THE COMPLICATIONS