Of the several descriptions of wounds, that which is "clean-cut" lends itself most readily to adjustment and rapid healing. The divided surfaces are regular, smooth, and easily brought into exact apposition, and the tissues being but slightly damaged should, under favourable conditions, heal by the first intention.
In the treatment to be adopted it will be necessary, in the first place,. to arrest haemorrhage by one or another of the methods referred to under that head. Then with sharp scissors the hair is removed close to the skin, or, if possible, shaved for a considerable distance round about the wound, and the skin thoroughly washed with soap and Lister's "Strong, Mixture", consisting of a 5-per-cent solution of carbolic acid and 2 per cent (1 in 500) of corrosive sublimate. Brushing at the same time with a pretty strong nail-brush will assist in rendering the cleansing efficient.
The soap should then be washed off with the antiseptic solution, and all adhering blood removed from the wound, together with any foreign-matter that may have entered it. This will be done at first with the fingers - picking off any tangible particles, and then by flooding the wound with a 5-per-cent solution of carbolic lotion. The two surfaces-of the wound are now brought together, and this must be understood to mean the entire surfaces of the divided parts, and not merely the outer edges or lips; for unless perfect coaptation of the more deeply seated parts is effected, any serum which may exude from the divided surfaces will gravitate to the bottom, and by increasing in amount tend to force the parts asunder and prevent healing; besides which it serves as a breeding-ground for micro-organisms should the wound prove not to be aseptic.
When the wound is of no considerable depth, but little difficulty will be experienced in effecting complete apposition of the divided structures; but in dealing with deep wounds special care and special methods of retention will require to be resorted to. In either case, the edges of the wound must be brought together by silk, wire, or catgut suture (pp. 416, 417), interrupted or continuous, as may be deemed desirable, and after the hairless surface has been freely sponged with carbolic solution, the wound must receive its permanent antiseptic dressing. Of the various substances employed for this purpose, the double cyanide of mercury and zinc gauze introduced by Lord Lister some years ago is regarded by our best surgeons as the most efficient and reliable. Before being used, it is wrung out in, or moistened with, a solution of carbolic acid (l in 40) or corrosive sublimate (l in 4000), and then applied over the wound, and for some distance around it. In this connection it should be pointed out that merely to cover the wound itself is to run great risk of failure by exposing it to attack from organisms which may obtain access from without, and defeat the object in view. Over this first layer of gauze four, five, or six others are placed, and these are covered by a thick layer of sterilized wool. Where practicable, a light bandage should be applied on the whole, so as to bring slight pressure to bear in maintaining complete apposition of the divided parts.
In deep incised wounds gravitation of blood and serosity to the more depending parts, leading to the formation of a cavity or pocket, and hindrance to healing, may take place, and will require to be provided against. This may be done in some cases by the careful application of pressure through the dressing, in others deep stitches will require to be inserted in order to bring the deeper parts of the wound into apposition, or a drainage-tube (fig. 412) must be inserted for a short time to allow for escape of any matter which may exude.
If the wound has been rendered aseptic and protected from subsequent disturbance and contamination, complete healing should be effected in from ten to fourteen days, when the dressing may be removed and the stitches withdrawn. Movement of the part, however, must be restricted for another week or ten days to allow of the union being perfected.
Fig. 412. - Drainage-Tube.
It must, however, be understood that the prospect of wounds in a horse healing by the first intention, even when made by the knife of the surgeon, is seriously interfered with by the dirty surroundings of the patient, the casual and imperfect after-attention he receives, and the difficulty in restricting movement of the part. These are so many obstacles to success which can only be overcome in exceptional cases. It results, therefore, that, however desirable it may be to bring about this mode of healing, the veterinary surgeon has in the main to rely on the more prolonged and tedious process of granulation.
Again, it is seldom that casualties of this kind are brought under his notice until many hours, or even days, have passed since their occurrence; and further, the implements by which wounds in horses are inflicted are mostly of the dirtiest possible description, being frequently covered with dust, decomposing filth, or earth, in which the bacillus of tetanus too often lurks. Moreover, the hair and skin through which they pass are more or less soiled and laden with bacteria. The advantages therefore offered even by an incised wound are largely discounted at the outset by these unfavourable conditions.
If, after being set up and dressed in the manner prescribed, the wound should show signs of soreness and pus formation, the dressing must be removed, and escape of the pus provided for by the insertion of a drainage-tube into the most depending part. The wound should then be redressed daily as before, until pus formation ceases. Should this not be accomplished, all the stitches must be removed, the wound laid open, and washed well with carbolic solution (1 in 20). Then the surface must be sponged over with undiluted liquefied carbolic acid, and the wound stuffed with the double cyanide gauze sprinkled with iodoform. This dressing should be changed daily, and the skin around the wound must be cleansed and disinfected at the same time with the 5-per-cent carbolic lotion.
In large wounds thus dealt with, the lips must be supported, either by bandages or by sutures, in the position most favourable to healing.