GENERAL METHOD FOR AMPUTATIONS

INDICATIONS (1) An arm which is so severely injured that there is no chance of recovery of any part of the hand, fingers or thumb. (2) A leg which is so severely injured that you cannot restore the continuity of its vessels or nerves, especially when there is gross contamination or severe muscle or skin loss. Loss of bone alone without nerve or vascular injury does not usually justify amputation. (3) Gas gangrene. (4) Established gangrene due to vascular injury. (5) Continued infection with severe bone or nerve injury. (6) Secondary haemorrhage if all other measures fail. (7) Multiple in injuries in a gravely ill shocked patient. Amputation may be the simplest and fastest way of removing large amounts of damaged muscle, and so saving his life. (8) Occasionally also for epitheliomas, bone tumours, or snake bites.

CAUTION! If you amputate for a malignancy, biospy it first.

ANAESTHESIA Relaxation is unecessary Ketamine is adequate (8.1). Subarachnoid (spinal) anaesthesia (A 7.4) is particularly useful for below knee amputations. Nobody likes hearing their bones being sawn through, so if a patient is conscious premeditate him heavily.

TOURNIQUET Use a tourniquet (3.8), except when you are amputating for ischaemia. Bleeding is a useful sign that a muscle is alive. If it is dead you may need to amputate higher up. A tourniquet may also make ischaemia worse. Release it before you suture the muscles, so that you can tie the bleeding vessels before you cover them.

When you use a tourniquet, exsanguinate the patient’s limb with an Esmarch bandage first (3.3), except when you are amputating for sepsis or malignancy which it may spread.

CAUTION! Don’t rely on digital pressure over the main vessels to control bleeding.

CUTTING FISH MOUTH FLAPS FOR AN AMPUTATION

Decide where you are going to saw the bone (the point of section) and plan the flaps in relation to that point. Place the angle of the fish mouth at the site of bone section. Mark them out carefully with methylene blue or scratch marks.

If the flaps are equal, make the length of each of them equal to 3/4 of the diameter of the limb as in A, Fig. 56-4.

If the flaps are unequal, make the longer flap equal to the diameter of the limb, and the shorter one equal to half its diameter, as in B. Cut through the skin down to the deep fascia, and reflect this up with the skin as part of the flap. The shin of the stump will need to slide over the deep fascia, so keep them together. If you are amputating for ischaemia, minimize trauma to the flaps. Handle them with stay sutures rather than with forceps.

CAUTION! (1) Start by making fish mouth flaps long. You can always trim them if they are too long later, but you cannot lengthen them if they are too short. (2) Cut them round not pointed. (3) Their combined length should be equal one and a half times the diameter of the limb at the site of bone section. (4) If you are amputating a severely lacerated limb, try to preserve all viable skin.

CONTROLLING BLEEDING DURING AN AMPUTATION

Early in the operation, find the major arteries and veins. Tie them separately with double transfixion ligatures (3.2) preferably linen. Then cut them between these ligatures. Later, after you have removed the limb, release the tourniquet slowly and tie the remaining smaller vessels. If the cut ends of the muscles bleed furiously, apply packs for five minutes.

If the amputation is very high you may have to expose the main artery higher up at one of the classical sites described in Sections 3.4 to 3.7.

CAUTION! (1) If you don’t use a tourniquet, find and tie the major vessels before you cut them. (2) Don’t clamp them, cut them and then try to tie them. If a clamp slips there will be massive bleeding. (3) Careful haemostatsis of the stump is essential. If a clot forms, it is easily infected.

CUTTING MUSCLES DURING AN AMPUTATION

Muscles always contract, after you have cut them. So cut them transversely about 5 cm distal the site of bone section. Leave them a little longer if you are using delayed primary closure, because they will have more time to shrink.

Use a long sharp amputation knife or carving knife to cut the muscles straight down to the bone. Don’t use a scalpel which makes many small cuts, and leaves shreds of injured muscle.

CUTTING NERVES DURING AN AMPUTATION

Don’t tie nerves. A painful neuroma will result, especially in the fingers. Instead, gently pull each nerve into the wound, cut it cleanly with a knife, then let it retract above the amputation site.

SAWING BONES DURING AN AMPUTATION

Clear the muscle from the site of section, and incise the periosteum all round it. Reflect this distally for one or two centimetres with the muscles, so as to leave bare bone for the saw.

Use a saw with well set teeth. Start by steadying it with your thumb. Draw it towards you across the bone a few times. When it has made a good slot in the bone, start sawing hard. Ask an assistant to hold the patient’s limb to steady it, and pull gently to prevent the saw locking in the bone and splitting it. Finally, remove any spikes with bone forceps, and bevel any protruding edges with a coarse rasp.

CAUTION! (1) Don’t reflect the periosteum proximally, because the bone under it will die, and a ring sequestrum will form. (2) Don’t damage the surrounding muscle with the saw. Cut the muscle first, or retract it well out of the way with a towel wrapped round the limb, as in Fig. 56-5, then saw. (3) Bone dust from the saw acts as a foreign body, so wash it away with saline.

DEALING WITH FAT DURING AN AMPUTATION

If a patient’s limb is very fat, cautiously remove as much subcutaneous fat as is necessary. Don’t remove too much, especially near the edges of the flap, or it may necrose. Learn to design flaps so that they come together accurately without dog ears’ If they form, leave them, they will soon disappear.

CLOSING THE WOUND AFTER AN AMPUTATION

SUTURES As indicated above, delayed primary suture will be safer. Suture the skin and deep fascia separately.

Close the flaps without tension, without leaving gaping areas between the sutures, and without tying them too tight.

DRAINS If you use delayed primary suture, no drains are necessary. If you close a stump by immediate suture, insert a drain under the muscle flap (if there is one) over the end of the bone. If possible, use a suction drain. If you don’t have one, insert a 2 cm corrugated rubber drain. Bring both its ends out loosely through the two ends of the incision as shown in F, Fig. 56-4.

If no blood is oozing from the drains, remove them at 48 hours, if blood continues to flow, leave them for a further 24 hours.

DRESSINGS Dress the stump firmly, but not too tightly. A plaster covering will make it more comfortable. Change the dressings at 48 hours.

POSTOPERATIVE CARE FOR AN AMPUTATION

As soon as the skin has healed, bandage the stump. For the leg, sew two 15 cm crepe bandages end-to-end. For the arm, use one 10 cm bandage. Roll the bandage tightly, then wind it round the stump. Apply more tension to the end of the stump, than to its base, or it will become bulbous. Reapply the bandage several times a day until the prosthesis is fitted. Don’t use adhesive strapping, or you may tear the skin of the stump.

THE FURTHER MANAGEMENT FOR AN AMPUTATION

Read on for: guillotine amputations (56.2), amputating for gangrene (56.3), amputating through the upper arm and elbow (56.4), the lower arm and wrist (56.5), above the knee (56.6), through the knee (56.7), below the knee (56.8), Syme’s amputation (56.9), and amputating through the foot and toes (56.10).

DIFFICULTIES WITH AMPUTATIONS

If a patient’s LIMB IS TRAPPED in a falling building, you may have to amputate it on the spot. Give him ketamine or intravenous morphine (8.6), or infiltrate his tissues with a local anaesthetic. Control bleeding by pressing on the pressure point, or with a tourniquet and then tie the vessels. Cut through his trapped limb with an amputation knife and a saw, as far distally as you can, and apply a firm pressure dressing to the stump. Transfer him to hospital for a formal amputation at the next most suitable site higher up his limb, either immediately, or later.

If a patient is SEVERELY SHOCKED, you can do a quick provisional amputation distal to the site of election. Later, when his wound has healed, you can do a definitive amputation with immediate primary closure. He will no longer be shocked, his skin will be normal, and there will be less danger of infection.

If you amputate in an emergency for shock, or sepsis, or to remove a grossly crushed limb, don’t do the final amputation until the stump is healing well.

If his STUMP BLEEDS SOME HOURS AFTER THE OPERATION (reactionary haemorrhage), take him back to the theatre, explore his wound, tie the vessels, leave his wound open and sew it up secondarily. To prevent this happening: (1) tie the major vessels carefully, (2) release the tourniquet slowly, (3) control the vessels thoroughly, and (4), apply a pressure dressing.

If his STUMP BLEEDS SOME DAYS LATER (secondary haemorrhage), it is likely to be serious. Explore the wound. In desperation, open it, pack it with dry gauze, and remove the gauze 48 hours later.

If his STUMP BECOMES INFECTED, this may have been your fault. Did you: (1) Close the wound by immediate primary suture, when delayed primary suture would have been wiser? (2) Fail to control bleeding, before closing the flaps, so that the blood clot beneath them has become infected? (3) Strip up the periosteum from the stump so that a ring sequestrum has formed and become infected?

If a PERSISTENT SINUS develops in the stump, explore it; you may find a piece of necrotic tendon, or an area of osteomyelitis. Another possibility is a stitch sinus. If the offending stitch might be securing a vessel, don’t remove it until you have tied the vessel higher up. Explore the stump, remove all dead and dying tissue, and pack it ready for secondary closure.

If the FLAPS BREAK DOWN, you probably cut them too short and closed them too tight. Wait until the granulation tissue is fit for grafting and then graft it. The final quality of the skin over the stump will be worse than it would have been if the flaps had survived, and it may break down later. Alternatively, you may have to amputate higher up.

If a PATCH OF GANGRENE forms in a flap, be careful, it may hide a larger area of necrosis underneath. You may be able to trim it away, or you may have to amputate again higher up, especially if a patient’s limb is ischaemic. If it is not ischaemic, you may be able to excise the gangrenous area, allow granulations to develop, and apply a split skin graft.

If he has GAS GANGRENE, amputate high up, through his shoulder if need be, and leave the wound open.

If a PROSTHESIS CANNOT BE FITTED, you probably designed the stump wrong. The reasons include: (1) bone adherent to the scar, (2) a spicule of bone sticking out through the skin, (3) a flexion contracture in a below knee or above knee amputation, (4) too short a stump.

CUT FLAPS LONG REFLECT THE DEEP FASCIA WITH THE SKIN DELAYED PRIMARY CLOSURE IS SAFER