The Actual Cautery. - Largely of the same empirical nature, yet doing something a little more calculated to destroy necrotic tissue and bring about its sloughing is the use of the cautery, both actual and potential.
The actual cautery may be beneficially employed for the relief of sub-horny quittor in at least two ways.
In the first place, it is often used - a blunt 'point-firing' iron being the instrument - instead of the knife as a means of evacuating the contents of the coronary abscess. Those who use it for this purpose are able to say this in its favour: it brings about the opening of the abscess without the unsightly haemorrhage attending the use of the knife, and at the same time just as effectually empties it. The opening made is not nearly so likely to close prematurely - that is, before a proper course of treatment of the wound has been carried out - and so leave necrotic tissue at its bottom. The intense tissue reaction it sets up is productive of a large slough, cast off by highly active inflammatory phenomena, which means that the remaining wound is one in which no dead tissue is left, and which is more amenable to treatment.
We have also seen the actual cautery used in sub-horny quittor, where that disease has reached a chronic fistulous stage, as a means of cauterizing the whole length of the lining of each fistulous passage.
At the present day this method is regarded as barbarous, and savouring too largely of the methods and practice of the old empirics. There is no denying the fact, however, that it is at times followed by a speedy and complete cure of what has for months been an intractable and apparently incurable quittor; and, honestly speaking, we ourselves can see nothing very greatly against the operation in certain cases save its appearance. In that it is certainly rough, and is not calculated to favourably impress the more critical of our clientele. With the animal chloroformed, however, much of what can really be urged against it disappears, and on farms and other places where a skilled and competent dressing of an operation wound cannot be looked for, it is sometimes wise to advise this method of treatment in preference to more advanced methods of operating. So far as we can judge, the after-effects are very little worse than those following other operative measures, more especially when a suitable case has been chosen.
This method of treatment is particularly applicable to cases of chronic sub-horny quittor in the more posterior parts of the foot. Here, if one or more fistulas exist, their openings are probed and the direction of the sinuses determined. In all probability they are burrowing down along-side the wall to the sole, where, for want of outlet, they are invading the substance of the plantar cushion or the plantar aponeurosis.
Should this preliminary probing demonstrate that neither of the fistulas run dangerously near the joint, then the operation may be decided on.
The animal is cast and chloroformed, the foot firmly fixed, and the horn of the quarter rasped away quite thin. The sole of the same side is also pared with the knife until the horn of both the quarter and the sole yields easily to pressure of the thumb. All that is then needed is three or four long, round, and pointed irons (about 1/4 to 3/8 inch in diameter) heated to redness. These are inserted into the fistulas, and the false mucous coat of these passages thus destroyed. When the iron, on being directed into the fistulous opening at the coronet, is found to travel alongside the wall, and to easily reach the sole, it should be made to go further still. The sole is penetrated, and a dependent opening thus made for the escape of the discharge that afterwards accumulates.
What happens now, of course, is that an intense and acute inflammation is set up along the whole track of the fistula, in which position the inflammatory changes were heretofore chronic. The whole lining of the fistula, and with it, we hope, all necrotic tissue, is cast as a slough, leaving nothing but healthy tissue behind. This, with a suitable dressing, heals and gives no further trouble.
The after-treatment consists in the application of hot poultices. These tend to greatly ease the pain, and at the same time to facilitate the removal of the slough. The poulticing should be continued, therefore, until the sloughing comes about, which happens, as a rule, at about the fifth or seventh day.
Immediately the slough is cast off, the poultices may be discontinued and dressing of the wound carried out. This consists of injections of solutions of zinc chloride 1 in 200, perchloride of mercury 1 in 1,000, carbolic acid 1 in 20, of Villate's solution, or of such other antiseptic as the surgeon may think fit. The dependent orifice at the sole should be kept open for as long as possible, being occasionally trimmed round with the drawing-knife, and scooped out with a sharp-edged director.
Directly a healthy and pink-looking granulation is observed along the track of the iron, and the discharge therefrom takes on a thick and yellow appearance, the strength of the antiseptic solutions should be gradually diminished. This point, in fact, is of great importance in treating all wounds of the foot. There is a great temptation, on account of the known excessive liability of the parts to septic infection, to use an antiseptic solution unduly strong. What must be remembered is that used too strong they themselves give rise to dead tissue, or to impermeable layers consisting of compounds of the discharges with themselves, and so create substances that prove a source of irritation and subsequent trouble.