GENERAL METHOD FOR SPLIT SKIN GRAFTING

INDICATIONS (1) Immediate primary grafting, where skin has been lost, or where you can only bring the edges of a patient’s wound together under excessive tension. (2) Delayed primary grafting. (3) Secondary grafting. Burns are the major indication.

Variations of these indications include: (1) The complete excision of a small recent deep burn (58.17). (2) All full thickness burns, bigger than 2 cm, usually between the 10th and 18th day. (3) To provide immediate skin cover where tissues lie exposed and nerves and tendons are near the surface. (4) Tropical ulcers (29.1).

Split skin grafts readily take on: (1) Favourable granulation tissue (57.3).(2) Healthy red tissue in a fresh wound. (3) Dermis. (4) Muscle. (5) Any vascular tissue or organ normally covered by aeolar tissue. This includes paratenon, nerves, fascia, and blood vessels. (6) The periosteum. (7) Cancellous bone. (8) The pleura. (9) The peritoneum. (10) The meninges. (11) The gut. (12) The shaft of the penis.

Grafts take less readily on: (1) Fat. (2) Joint capsules. (3) Ligaments.

Grafts fail to take on the following tissues, although they may be able to bridge a small gap: (1) Bare dry white tendon, except in young children. (2) Bare cortical bone. (3) Hyaline cartilage. (4) Open syovial joints.

CONTRAINDICATIONS Besides trying to graft a tissue which won’t accept a graft, other contraindications include unfavourable granulations and untreated Strep. pyogenes or Pseudomonas in the wound.

Relative contraindications include the face. Split skin grafts look ugly here. They are less satisfactory than full thickness grafts, or pinch grafts, over areas which have to bear pressure, such as the heel.

CAUTION! (1) Don’t try to graft a patient while he is anaemic. Raise his haemoglobin above 6 g/dl first. (2) Don’t try to graft too large an area at once, or he may bleed to death. 10% of his surface area is the absolute maximum at any one time.

ANTIBIOTICS If you are grafting a burn, especially a large one, give the patient penicillin for 2 days before grafting and 3 days afterwards to control possible streptococcal infection.

PREOPERATIVE PREPARATION Bathe the patient. Shaving the donor site is optional, but always scrub it well with soap and water.

EQUIPMENT A skin grafting knife, two graft boards, liquid paraffin, skin hooks, non–toothed forceps for handling the graft, vaseline gauze, a bowl of sterile saline to put the graft in, sterile cotton wool, and a sterile screw topped jar for storing excess graft.

Find two assistants.

ANAESTHESIA FOR SKIN GRAFTING If you have prepared the patient’s wound adequately so that and it does not need scraping, and you are not going to sew the graft in place , you need not anaesthetize it. If possible, use local anaesthesia for the donor area because he is more likely to cooperate. (1) Use plenty of a very dilute local anaesthetic, such as 0.4% lignocaine with adrenaline, to puff out the skin all over the donor site. If you raise it like a plateau, it will be easier to cut. Raise blebs in suitable places and then infiltrate the whole area with a long needle just below the dermis, as in Fig. 57-4. This is the best method of local anaesthesia for the arm. (2) Take skin from his thigh by blocking both his femoral nerve and the lateral cutaneous nerve of his thigh (A 6.22). (3) If you are going to take an extensive graft from several sites, give him a general anaesthesic. (4) You can use ketamine; if you give him diazepam at the end of the operation (A 8.1), he is unlikely to thrash about as he recovers and so disturb the graft.

PREPARING A WOUND FOR GRAFTING

Start by preparing the wound, so it will have stopped bleeding when you come to apply the graft.

Clean the granulations with a saline swab and rub them firmly so that they bleed. Remove all slough, debris, grease, or pieces of vaseline gauze. Unless the granulations are very thin, scrape them with a piece of dry gauze or a wooden tongue depresser, or with a scalpel with the blade held at 90. Scraping granulations like this will remove the tendency to subsequent fibrosis and contracture.

The wound should bleed well as you prepare it, but bleeding should stop before you apply the graft. So raise the patient’s wound and apply warm packs, or dry gauze and a bandage. Don’t use diathermy, or catgut. Instead, apply artery forceps to the small bleeders and twist them off.

If you cannot control bleeding by the above methods, apply the graft as a sheet, and see if this stops it. If it does not, mesh it to allow drainage. Or, put the graft back on the donor site, and put dry gauze on the patient’s wound. Two days later, under ketamine or light sedation, lift off the graft and reapply it to the wound.

PREPARING THE DONOR SITE FOR GRAFTING

Scrub the donor site with cetrimide and a scrubbing brush, and then swab it with a mild antiseptic, such as cetrimide or hexachlorophane soap. Don’t use iodine or spirit, because they may kill the graft. Drape the donor site in towels.

PREPARING TO CUT Place yourself comfortably before starting.

The leg

On the patient’s right side, and assuming you are right handed, cut from below upwards, with a forehand stroke. On his left side cut from above downwards.

Ask your assistant to support the skin of the patient’s thigh from underneath, as in C, Fig. 57-5, so as to make its upper surface flat, and under slight tension from side to side. This will allow you to make a smooth cut with neater edges.

The arm

Abduct the patient’s arm, and place it on a wide arm rest or table. Ask your assistant to put one of his gloved hands behind it, so as to stretch and flatten the skin on its antero–medial surface. Cut from his shoulder downwards.

Stand inside his abducted right arm, or outside his abducted left arm.

CAUTION! The skin of the upper arm is thin, so don’t cut a full thickness graft by mistake.

The chest

If necessary, fill out the skin from between the ribs of a thin patient by injecting his subcutaneous tissues with saline, so as to make a flat surface.

CUTTING THE GRAFT

ADJUSTING A HUMBY KNIFE In this knife the thickness of the skin to be cut is controlled by a rod. The position of this rod is controlled by a screw at one end, and a graduated lock nut at the other. You will have to learn by practice what thickness of graft these calibrations represent. Hold the knife up to the light and vary the distance between the blade and the rod. If you think you could just slip a razor blade between them (a little less than 0.5 mm), it is about right, perhaps a little narrow. Make it too narrow rather than too wide, because if the graft is too thin, you can always thicken it. If the rod touches the blade anywhere thev are far too close. Make sure the blade and the knife are flexible, so the thickness of the graft also depends on how hard you press.

Lubricate the back of the knife with liquid paraffin. Keep it clear of the roller, or it may cause the graft to wind round it.

Ask your assistant to hold one board behind the knife, to keep the board still, and to press on the skin so as to hold it flat and in tension as you move the knife, as in A, Fig. 57-5. Hold the second board in your left hand, cut towards it, and move it closely in front of the knife as you cut (B). Use the second board to keep the skin flattened in front of the advancing knife blade. Advance the board and the blade together along the limb (B). Apply the knife to the skin at a slight angle and use a regular sawing movement as if you were cutting a loaf of bread. Advance it slowly, and press gently. The graft usually collects in folds on the knife. If it does not, ask your assistant to pick its end up. When you get to the end of the graft, either cut it with scissors, or bring the knife to the surface.

CAUTION! (1) Don’t force the knife down the limb. (2) Don’t stop or pull the knife backwards. (2) You will be wise to take more graft than you need and store it, so that you can apply it later to areas which do not take.

After you have cut about 1 cm of graft, inspect it for thickness. Assess this by: (1) Tranlucency. A very thin graft is translucent, like tissue paper. Thicker grafts are progressively more opaque. (2) The pattern of bleeding points. A thin graft produces many tiny points, a thicker graft fewer larger ones.

If the graft from a black skinned patient is a thin translucent grey, as it lies on the knife blade, it is the right thickness. If it is white and milky, and curls up vigorously, it is too thick.

If there are large bleeders every few millimetres, you have cut too deep. The donor area should bleed all over from fine bleeding points.

If you can see fat globules, you have cut much too deep, and have taken a full thickness graft. Stitch it back and start again somewhere else. Either to sew up the donor area, or better, to cover it with a very thin split skin graft from another site.

If a large area is to be covered, cut the sheet of skin as wide as possible, and up to 15 cm long. If necessary, cut several sheets. Cut the graft thin so that you can take another crop of skin from the same donor area 10 days later. You may be able to get three or four crops of skin from the back of a patient’s thigh, or his buttocks, or the back of his trunk.

Keep the graft covered with saline soaked swabs until you are ready to store or apply it. If there is much delay, replace it temporarily on the donor area.

If you are worried that you may have cut too deep, start again a little way away at the same site. If you realy have cut too deeply, immediately apply a thin split skin graft from somewhere else.

CARING FOR THE DONOR SITE AFTER TAKING A GRAFT

The donor site always bleeds, and if it is large, the patient may lose much blood. Minimize this by immediately applying a hot moist pressure pack. Later, when you have applied the graft and dressed it, remove the pack and replace it by plain gauze or vaseline gauze, and a pressure bandage. You now have a choice of 3 methods.

The exposure method saves dressings. At 30 minutes to 48 hours remove the pressure dressing down to the inner layer of gauze. Leave the exposed area to dry and form a crust. The inner layer of gauze will separate with the crust at 10 days. Or, apply no gauze and dry the wound with a hair drier.

The occlusive method. Pad the wound generously to prevent blood soaking through, and bandage it, preferably with an elastic bandage. At 7 to 10 days remove the dressings.

The ’Op-site’ method. ’Op-site’ is an expensive self adhesive plastic sheet, permeable to water vapour but not to bacteria. It is the ideal way of caring for the donor area.

If the dressings have stuck to the donor site, l eave them in place. If you tear them off, the wound will be very slow to heal.

If the donor site becomes infected, treat it like any other superficial wound with frequent cleaning and changes of dressings.

APPLYING THE GRAFT

Drape the graft over the wound with forceps. If it curls up, lay a piece of vaseline gauze on one of the boards, and put the graft on it, raw surface up. The graft will stick to the vaseline gauze, which will stop it rolling up, and enable you to cut and handle it more easily.

CAUTION! Be sure you apply the graft the right way up. The under side is shiny, the dull side must be on top as the graft lies on the wound.

SINGLE SHEET GRAFTS Always pierce some holes in the graft, so that the wound can drain through it. Trim it to shape.

If you have to use several pieces of graft, lay them edge to edge, and let them overlap the edges of the wound a little. Make sure that they fit snugly to the bottom of any irregular areas, and do not bridge any concavities.

If the sheets of graft cross a joint, make sure that the joint between them (where a scar may form), goes across a limb not along it—this is CRITICALLY important.

Sewing a single sheet graft in place is optional. Some surgeons almost always sew grafts in place, and some almost never do. Sewing is particularly useful in the eyelids, the palmar surface of the fingers, the axilla, and the popliteal fossa. These are the places where a graft so easily slips. Use small curved needles and fine silk sutures. Insert the needle from within the graft outwards, as in B, Fig. 57-8.

If you see any blood clots under the graft, remove them. Wash them away from under it with saline, a syringe and a blunt needle. If some clots still remain, pull them out with non–toothed dissecting forceps. Immediately apply pressure to control further bleeding.

MESH GRAFTS are useful on rough surfaces. Don’t use them on exposed areas, such as the face. Mesh a graft as in Fig. 57-6. Flatten it out on a piece of wood and use a No. 10 or 15 blade, or an osteotome, to make the holes. If necessary, the bridges of skin making the mesh can be very narrow indeed.

STRIPS OR PATCH GRAFTS Take the whole of the graft, stick it on pieces of vaseline gauze, raw surface upwards, and cut this into strips, or patches the size of a small postage stamp. Apply these to the wound.

DRESSINGS FOR SPLIT SKIN GRAFTS

These are absolutely critical-it is the movement of a graft over its bed which stops it taking. There are several alternatives, and little agreement as to which is best.

THE FIRST METHOD is shown in Fig. 57-7 and uses a stent of cotton wool balls soaked in saline to keep the graft in place.

THE SECOND METHOD applies 5 mm of dry gauze between layers (2) and (3) of the first method in Fig. 57-7. It omits layer (4), and covers layer (5) with a single layer of gauze extending widely beyond the wound and stuck to the skin around it with tincture of benzoin.

THE THIRD METHOD applies vaseline gauze to the graft, followed by plenty of dry gauze and a bandage.

THE FOURTH OR TIEOVER METHOD is very effective in difficult situations where a graft has been sewn in place. Use it as in A, Fig. 57-8, for a patient’s eyelids, his axilla and for small intricate grafts, such as those over the tips of his fingers, and underneath his chin.

Stitch the graft in place all round the defect (B), but leave one end of each suture loose (C). Finally put a ball of moist cotton wool on the graft, and tie the loose ends of the sutures over it (D). The wool will keep the graft firmly applied to the wound.

POSTOPERATIVE CARE FOR SKIN GRAFTS

If a joint as to be grafted, a plaster cylinder over the dressings is very useful.

If a flexure has to be grafted, the position in which the patient’s limb rests is critical, so see Figure 58-16, on the prevention of contractures in burns.

If a flexure does not have to be grafted, the position of the limb is not critical. Put a grafted arm in a sling, and put a grafted leg to bed and raise it.

CAUTION! The graft must not move over its bed. This may be difficult to prevent. If necessary, you may have to strap a child to a frame, or apply a cast.

Leave the dressing on for 5 to 7 days unless there is some good reason for looking at it. Do the first dressing yourself, so that you can inspect your handiwork. At first remove only the superficial layers. Leave the layer of vaseline gauze which was used to spread the split skin. Remove this later when the graft is firmly adherent.

CAUTION ! Make sure your nurses remove any dressings with the greatest possible care, as in B, Fig. 57-7, or they may strip away the graft with the gauze. If necessary, soak the gauze away with saline. (2) Use vaseline gauze for the first dressing only. If you use it repeatedly, granulomas may form.

If there are any granulating areas, clean them with saline.

If they are more than 1 cm in diameter, regraft them with stored skin (57.8).

If blisters appear, i ncise them, or aspirate them with a syringe.

If the donor or recipient areas are so painful and itchy that the patient scratches them, sedate him, dress them, and consider applying a cast.

Start active joint movements a week after grafting. After 2 weeks you can usually remove all dressings.