Part 66 (1/2)
This may be partially accounted for by the fact that although, theoretically, the application of skin grafts is easy, yet, practically, the technique is difficult. Those who favour skin-grafting point to the fact that healing of the wound may take place within five weeks, whereas, if grafting be not undertaken, cicatrization of the cavity, even under favourable conditions, can hardly be expected to occur before eight to twelve weeks.
The skin-grafting operation as suggested by Charles Ballance is generally performed as a second stage, some ten or more days after the primary operation. This, from the patient's point of view, is a serious matter; and the disappointment caused by the grafting not being always successful has induced many to give it up and to be content with what seems to be a more certain, though more prolonged, after-treatment.
More recently, however, it has been shown that in suitable cases skin grafts, if applied at the time of the completion of the primary operation, will take just as well as at a later date. This altogether alters the aspect of the case. If at the end of the primary operation it be certain that all the diseased bone has been removed and the cavity has been rendered aseptic, there can be no objection to the immediate application of skin grafts. If the result be successful, the period of after-treatment is considerably curtailed. If, on the other hand, it be not successful, the patient, beyond having a raw surface on his arm or leg for a few days, is no worse off than if the graft had not been applied.
Skin-grafting, however, cannot be done in every case. Two conditions are necessary for its success: firstly, that all the diseased bone has been removed; and secondly, that the wound cavity is aseptic.
Immediate skin-grafting, therefore, should not be employed if, in addition to the chronic disease, there be acute inflammation of the mastoid process, or of the subcutaneous tissues covering it; nor should it be done if it has been necessary to expose the dura mater over a large area, nor if there be any possibility of some subsequent intracranial complication. In such cases it may be justifiable to do skin-grafting after the acute symptoms have subsided. If, however, the case be progressing satisfactorily, the advisability of submitting the patient to a second operation should be a matter of careful consideration.
Disease of the inner wall of the tympanic cavity, or around the orifice of the Eustachian tube, is also a contra-indication against grafting, as the graft, if applied, will not take over these areas. The author's opinion with regard to skin-grafting is that, if it can be applied immediately after the completion of the primary operation (and the conditions justifying this are limited), it may be done. If, however, the conditions be such that they will not permit of this, it should not be done at all.
=Technique.= _When the grafting is done at the completion of the mastoid operation._ The first step is to see that the mastoid wound cavity is rendered thoroughly aseptic and dry. All bleeding points in the soft tissues are arrested by means of pressure forceps. The mastoid cavity is then filled with hydrogen peroxide lotion, which is afterwards syringed out with a warm saline solution, the cavity being dried with sterilized strips of gauze, and finally packed from the bottom with a fresh strip.
The size of the graft, which is usually taken from the thigh, should be at least 2 inches in width and 4 inches in length. The skin is cleansed by was.h.i.+ng it with soap and water, then with ether, and finally with normal saline solution, the part being afterwards dried with a sterilized towel. It does not matter what type of razor is used to remove the graft, so long as it is sharp. The chief point to observe, in order to secure success, is to see that the skin is kept uniformly stretched--the tighter the better. The technique of removal of grafts is described elsewhere (see Vol. I, p. 670). The graft taken from the leg is transferred to a large spatula and smoothed out over its surface. The auricle is now pulled forward, and the gauze strip is removed from the mastoid cavity. The spatula is laid across the surface of the cavity so that it rests on the anterior margin of the wound surface (Fig. 234).
With a sharp probe the edge of the graft, which just overlaps the spatula, is held in position at this point, the spatula being gently retracted so as to leave the graft stretched across the surface of the wound cavity. With a 'stopper' (Fig. 235), the graft is now pushed inwards towards the tympanic cavity.
A gla.s.s pipette (Fig. 236), having a curved beak, is then pa.s.sed inwards beneath the graft until its point, directed downwards, lies within the tympanic cavity (Fig. 237). Any blood which has acc.u.mulated between the bone and the graft is now sucked out, and in doing this the graft becomes closely applied to the bone surface (Fig. 238). After removing the pipette, any part of the graft which is not adherent to the bone is smoothed out over its surface. The tympanic cavity and the innermost portion of the mastoid cavity are then plugged with sterilized pellets of cotton-wool wrapped in gauze and dusted with aristol powder. The outer portion of the cavity is filled up with a strip of gauze, its end being brought out through the external auditory meatus.
[Ill.u.s.tration: FIG. 234. SKIN-GRAFTING OF MASTOID WOUND CAVITY AFTER OPERATION. Skin graft being transferred from the spatula to the mastoid cavity.]
The posterior part of the graft, still projecting beyond the posterior margin of the wound, is now turned forwards so as to form a covering over the gauze filling up the wound cavity (Fig. 239). On the auricle being restored to its normal position, this portion of the graft is brought into contact with the subcutaneous tissues of the skin forming the post-aural flap, which now forms the outer wall of the mastoid cavity. The posterior incision is closed with sutures and a dry dressing and bandage are applied to the ear.
[Ill.u.s.tration: FIG. 235. BALLANCE'S 'STOPPER' FOR PUs.h.i.+NG IN THE GRAFT.]
_If skin-grafting be performed a week or more after the primary operation._ The post-aural wound, now healed, has to be reopened. In doing so there may be considerable bleeding, which must be arrested. The mastoid cavity is usually found to be covered with a fine layer of granulations. They are curetted away carefully, special attention being paid to the region of the Eustachian tube and the floor of the tympanic cavity. After removal of the granulations, the bone should appear uniformly smooth though somewhat vascular. If any points of carious bone be found they should be removed freely with the gouge or burr.
Considerable time may have to be spent in arresting the oozing from the surface of the bone cavity. This is best done by was.h.i.+ng out the cavity with hydrogen peroxide solution and then plugging it tightly for a few moments with adrenalin solution. The gauze is withdrawn in a few moments. If there be still oozing, the pressure will have to be repeated until it ceases. The method of applying the graft is the same as already described.
[Ill.u.s.tration: FIG. 236. PIPETTE FOR SUCKING AIR AND FLUID FROM BENEATH THE GRAFT.]
[Ill.u.s.tration: FIG. 237. SKIN-GRAFTING OF MASTOID WOUND CAVITY AFTER OPERATION. Skin graft in the act of being sucked into position by the pipette.]
=After-treatment.= The outer dressing may be changed every second day, but the wound itself is not interfered with until the eighth day. If asepsis has been obtained, the posterior wound has usually completely healed, so that the st.i.tches can be removed at the first dressing. Owing to the secretion from within the cavity there may be a certain amount of odour, and as a rule some purulent discharge from the meatus. Under good illumination the strip of gauze is gently removed through the meatus and afterwards the small pellets of cotton-wool. In order to make certain that all are removed, a note should be made at the time of transplanting the graft as to how many were inserted in the wound cavity. The ear is now syringed out gently with a weak solution of hydrogen peroxide and afterwards dried by mopping it out with small wicks of cotton-wool.
A speculum is next inserted into the meatus and the cavity thoroughly examined. Any portions of the graft not in absolute contact with the bone or which overlap the skin of the meatus will have died, and can be removed by forceps. Care, however, must be taken not to pull off these portions too forcibly, as in doing so other pieces of the graft may be torn away. The external meatus is then plugged with a tiny piece of gauze and a dry dressing applied. If the graft has not taken and has died, it will be expelled at the first dressing on syringing.
[Ill.u.s.tration: FIG. 238. SKIN-GRAFTING OF MASTOID WOUND CAVITY AFTER OPERATION. Skin graft in position.]
[Ill.u.s.tration: FIG. 239. POSTERIOR PORTION OF SKIN GRAFT COVERING OUTER SURFACE OF WOUND CAVITY.]
Further treatment consists in syringing and afterwards drying the cavity daily. From day to day the outer layer of the graft will gradually come away piecemeal. At the end of the second week the patient can usually go home and carry out the treatment for himself, but he should be seen by the surgeon at least once a week until complete healing has taken place.
If the graft has not taken uniformly over the surface of the bone, small patches of granulations may be seen covering these areas. Under cocaine anaesthesia these patches should be curetted. If the granulations recur repeatedly, it means that there is some underlying carious bone, and that healing will not take place until the tiny fragment is eventually exfoliated.
=Results.= Statistics vary. There is no doubt that the results are better according to the experience of the surgeon with regard to grafting. If it be only applied in those cases in which it is certain that all the diseased bone has been eradicated at the primary operation, then the percentage of success with relation to failure is very high.
If, however, skin-grafting be adopted as a matter of routine, the ultimate result is probably not so good as in a similar series of cases in which grafting has not been done.
=Skin-grafting through the external meatus.= This has been advised chiefly in order to avoid a second operation.
The technique of applying the graft is practically the same as that for transplanting a large graft. The same care must be taken to get the interior of the mastoid cavity aseptic and dry. To avoid a general anaesthetic, the small grafts may be removed from the arm or leg under local anaesthesia produced by a subcutaneous injection of Schleich's solution. The graft is transferred from a small spatula to the edge of the meatus and then coaxed into position within the cavity by means of probes. The grafts are kept in position by small pellets of cotton-wool covered with gauze. If successful, the grafting may shorten the duration of the after-treatment. It is not, however, so satisfactory a procedure as applying a large graft directly through the post-aural wound.