DIAGRAM OF HOOF SHOWING THE POSITION OF THE THREE GROOVES MADE IN THE TREATMENT OF LAMINITIS.
FIG. 120.—DIAGRAM OF HOOF SHOWING THE POSITION OF THE THREE GROOVES MADE IN THE TREATMENT OF LAMINITIS.
The animal is cast, the shoes removed, and three vertical grooves made in the wall. The first is cut down the centre of toe, extending from the coronet to the ground surface. The second is made to the right of this, and the third to the left, each following the direction of the horn fibres, and each distant about 2 inches from the first (see 1, 2, and 3, Fig. 120).
Each of the grooves must run completely from the coronary margin to the ground surface, and each should be carried through the substance of the horn until the horny laminæ are reached. This done, the underneath surface of the foot is grooved at the white line (see curved groove 4, Fig. 121) in such a manner as to entirely isolate the two pieces of hornaandbfrom the remainder of the hoof.
Expansion of the horny box is thus brought about, while at the same time the semicircular groove at the toe is made deep enough to allow of the escape of the exudate.
If thought wise by the operator, the two pieces of hornaandbmay be isolated, and the exudate given exit by making the fourth groove in the position of the dotted lines in Fig. 120—that is to say, at the lowermost portion of the sensitive structures. By this means the sole will be left intact.
LOWER SURFACE OF FOOT SHOWING POSITION OF THE GROOVES MADE IN THE TREATMENT OF LAMINITIS.
FIG. 121.—LOWER SURFACE OF FOOT SHOWING POSITION OF THE GROOVES MADE IN THE TREATMENT OF LAMINITIS.
Fuller instruction for making the grooves and the instruments required will be found described in Section C of Chapter X.
The animal should be afterwards shod, and the bearing on the portionsaandbof the wall removed. Almost immediate relief is afforded the patient.
Recorded Cases.—1. 'On the evening of September 28 last, I was called rather hurriedly to attend a posting-horse which had just arrived from a twenty-one miles' journey, and was said to be "very ill." I lost no time in proceeding to the spot, and found my patient "very ill" indeed. No need for long consideration as to diagnosis; the symptoms showed at once that I had an uncommonly severe case of acute founder before me. On examination I found the pulse was 120, the respirations 100, and the thermometer 106° F. The poor brute could not move, the fore-legs were well out before, and the hind-legs thrown back behind; in fact, he was, as one might say, propping himself up with his four legs!
'On examining his feet, I discovered what I had never either seen or heard of before—namely,blood freely oozing outat the coronet of all four feet; if anything, the hind-feet were the worst, and, showing that this bloody discharge at coronets had commenced during progression and before he was stabled, the inside of the thighs were all shotted over with blood, which had been thrown up by his feet while he was trotting or walking. He was completely soaked all over with perspiration.
'My prognosis could not well be otherwise than unsatisfactory. I resolved, however, to do all I could to relieve the poor suffering brute. As a matter of course, jugular phlebotomy was utterly impracticable; so, to relieve the pressure in the feet, I had him (after, with extreme difficulty, removing the shoes) bled, or rather opened, at all four toes, and hot poultices applied. On opening the off-side toe, in both hind and fore feet, I found an escape of very dark-coloured blood, with a great many bubbles of gas, thus showing that the destructive process was fairly established in the two bony extremities mentioned. The near fore and near hind feet showed no signs of gas-bubbles on being opened at the toe.
'I gave a laxative in combination with a diffusible stimulant, and ordered doses of aconite and potassium iodide; I also applied strong sinapisms to each side, immediately behind the shoulders. After three hours I found my patient rather easier; respiration about 90, and temperature 104°; willing to take a little water, and even attempted to take some hay. Ordered continued applications of hot water to the poultices at feet, and clothed him up for the night. Next morning there was little improvement; respirations over 80, and temperature 103.5°. Continue same treatment. Second morning, horse apparently easier; temperature 102.5°, but very difficult respiration; laxative had operated during the night; ordered diffusible stimulants. About two hours and a half after my last visit, the horse turned round in his stall and dropped down dead!
'History of the Horse.—He belonged to an extensive horse-hiring establishment; was purchased a short time before for £60—a long price for a post-horse—had recently suffered and been off work from some "severe cold"; was taken out, and did forty-seven miles of a journey the daybeforeI saw him; on forenoon of the day on which he was attacked he did two or three short turns, and then twenty-one miles of a journey in the afternoon, during which he became so ill as scarcely to be able to conclude the twenty-one miles; this was the last turn he was to do. He was a grand stepper, and no doubt was pushed a little during this final journey, as the driver intended, after a short rest, to finish off with the twenty-six miles between this and home. With the short turns on the second forenoon, this would have been over 100 miles in less than two days, with a horse just out of asevere cold.'[A]
[Footnote A:Veterinary Journal, vol. xvii., p. 314 (A.E. Macgillivray).]
2. 'Whilst attending a patient on a farm on September 5 last my attention was called to a cart-horse, five years of age, that had been castrated in the standing position by a travelling castrator about ten days previously.
'I found the animal presenting the following symptoms: Head down, blowing hard, very dull, and disinclined to move, temperature 105° F., hard, rapid, slightly irregular pulse, membranes injected, appetite lost; scrotum, sheath, and penis tremendously swollen, castration wounds unhealthy, and exuding a thin, reddish-brown discharge of a most foetid odour.
'The next day well-marked symptoms of laminitis were present. I finally ceased attending him about the middle of October, and at the end of that month he was turned out for the winter.'[A]
[Footnote A:Veterinary Record, vol. xiv., p. 649 (Charles A. Powell).]
3. 'On July 8 an interesting case of laminitis came under my notice. The subject was a mare, eight years old, which had been running on the common here for some months, and was taken up on the night of July 2 by a boy, who did not observe anything amiss with her. The following morning, on the owner going to the stable, he found the animal in great pain, and at once sent for me. I discovered her to be suffering from laminitis, and saw her again in the evening, when she was much worse. The attack proved to be a most severe one.
'The owner informed me that she had not been allowed any corn for two months, and that she had no distance to travel on the road from the common.
'Though on such a poor pasture, the mare was very fat; she had never been unwell before this attack.
'This is the first case I have seen of laminitis occurring when the animal was on grass.'[A]
[Footnote A:Veterinary Journal, vol. ix., p. 176 (W. Stanley Carless).]
1. CHRONIC LAMINITIS.
Definition.—A low and persisting type of inflammation of the sensitive structures of the foot, characterized by changes in the form of the hoof, and incurable pathological alterations within it.
Causes.—Chronic laminitis more often than not is a sequel to the acute form we have just described. With an attack of acute laminitis that defies treatment, and does not end in resolution in from ten days to a fortnight, then the chronic form may be expected.
The brittle horn, convex sole, and other changes we have described under Pumiced Foot may, however, be regarded as a chronic laminitis, and this condition, as we have already indicated in Chapter VI., may run a course slow and insidious from the onset.
Symptoms.—When the disease arises without previous acute symptoms, the first thing noticeable is an alteration in the gait. The animal begins to go feelingly, especially when first moved out from the stable. Our opinion is asked as to the cause of the lameness, and an inspection is made. With the changes in the form of the hoof as yet wanting, we have nothing to guide us, and other causes for the lameness suggest themselves, probably corns. Evidence of these is not forthcoming, and we in all probability withhold our opinion until a later visit. On the second or a subsequent call we are perhaps lucky enough to find our patient down. Diagnosis is then rendered easier. Made to rise, the animal stands in the attitude we have described as indicative of laminitis. We have him walked and trotted out. The symptoms of tenderness disappear, and the animal soon goes fairly sound. He is, in fact, workable—that is, by anyone who is careless as to the comfort of his beast.
When following an acute attack, we have the most marked symptoms of pain and distress, somewhat abating after the second or third week. The walk, however, is still painful, and, for a short time after rising from the ground, even difficult.
In short, in both cases we have the horse going on his heels, with a walk that is painful, and with symptoms of pain that are most apparent when moved on after a rest.
Later, the changes in the form of the hoof begin to appear. It seems to have lost its elasticity, and is seen to be dry and chippy, and to have become denuded of its varnish-like outer covering.
In addition, it is of largely altered shape. The toe, by reason of the animal walking on his heels, and by reason of an increased growth of horn, becomes elevated, so that the front of the wall, instead of forming an obtuse angle with the ground, comes to run very nearly horizontal with it. The horn of the heels, as compared with that of the toe, takes on an increased growth. The same thing we have already indicated as happening at the toe, though in lesser degree. Taken together, this increased growth of horn at the toe and at the heels has the result of lengthening the diameter of the foot from before backwards, the transverse diameter remaining more or less normal. The hoof thus loses its circular build, and comes to approach nearer an elongated oval.
FOOT BADLY DEFORMED AS A RESULT OF CHRONIC LAMINITIS.
[FIG. 122.—FOOT BADLY DEFORMED AS A RESULT OF CHRONIC LAMINITIS. At this stage, too, the pathological 'ribbing' of the hoof is observable. The outer surface of the wall becomes marked with a series of ridges encircling the hoof from heel to heel (see Fig. 81, which illustrates a moderate deformity of the hoof occurring after laminitis). In the badly laminitic hoof, however, this deformity is largely increased, until in some cases the shapeless mass can hardly be likened to a foot at all (see Fig. 122).
The inferior or solar surface of the foot also offers certain changes for our consideration. The first thing that strikes one is the convexity of the sole. This, as we have already pointed out, is due to descent of the os pedis, and the highest point of the convex portion is that immediately in front of the apex of the frog. Here the horn is sometimes found to be quite yielding to the finger, is excessively thin, and is more or less granular and inclined to break up under manipulation. As a consequence, any rough use of the drawing-knife, or an accidental wounding with sharp flints or stones, leads to exposure of the sensitive structures and local gangrene.
With the horn of the sole thus deteriorated by reason of excessive and continued pressure upon the parts secreting it, it is not surprising to find that, in many cases, actual penetration of it with the os pedis occurs. It is the anterior portion of the inferior margin of the bone that makes its appearance, and shows itself as a small semicircular white or dark gray line on the sole.
SOLAR ASPECT OF FOOT WITH CHRONIC LAMINITIS,
FIG. 123.—SOLAR ASPECT OF FOOT WITH CHRONIC LAMINITIS, SHOWING ITS ABNORMAL OVAL SHAPE FROM BEFORE BACKWARDS, AND THE EXCESS OF HORN GROWING FROM THE WHITE LINE IN THE REGION OF THE TOE.
Exposure of the bone is soon followed by its necrosis, in which case the wound takes on an ulcerating character. From it there is a discharge of pus, black in colour and offensive in smell, and, protruding from the opening, are excessive granulations of the remains of the sensitive sole.
The 'white line,' so apparent when a normal foot is cleaned with the knife, can no longer be sharply distinguished from the surrounding horn, while in some cases the horn composing it takes on an abnormal growth at the toe (see Fig. 123). This adds still further to the abnormal lengthening of the antero-posterior diameter of the foot already mentioned.
In other cases horn in this position is altogether wanting, and in its place is a well-defined cavity, into which the blade of a knife can be readily passed. This cavity is bounded in front by the original wall of the hoof, and is here lined by a degenerated and hypertrophied growth of the horny laminæ. Posteriorly the cavity is bounded by the front of the os pedis, and is lined by a thin growth of horn secreted by the keratogenous membrane covering the bone. Superiorly the cavity is quite narrow, and extends to near the lower surface of the coronary cushion, while inferiorly, at its open portion, it is often 1/2 inch to 1 inch wide. Laterally it extends on each side of the toe to the commencement of the quarters.
LONGITUDINAL SECTION OF A FOOT WITH LAMINITIS OF THREE WEEKS' STANDING.
FIG. 124.—LONGITUDINAL SECTION OF A FOOT WITH LAMINITIS OF THREE WEEKS' STANDING. On the anterior face of the cavity, in front of the os pedis, are thickened horny laminæ. Due to the sinking of the bony column, the os pedis has perforated the horny sole.
Exploration with a director, or with the blade of a scalpel, removes from the opening a dry detritus. This is composed of the solid constituents of the escaped blood, the dried remains of the inflammatory exudate, and broken-down fragments of cheesy-looking horn. The size to which the cavity may sometimes extend is illustrated in Fig. 124. The thickened horny laminæ forming the anterior boundary of the cavity are here depicted, together with commencing perforation of the horny sole by the os pedis. It is this cavity which, when opened at the bottom and discharging its mealy-looking contents, is known as seedy-toe, for a further description of which see p. 293.
The lameness occurring with chronic laminitis does not always persist. As time goes on the sensitive structures accommodate themselves to the altered form and conditions of the horny box. In certain situations—namely, where pressure is greatest—the softer structures become atrophied, and sometimes even wholly destroyed; while in other positions the changes in form of the hoof tend to increase in size of its interior, with a consequent diminution of pressure upon, and increased growth of the structures within it.
Pathological Anatomy.—In detailing the changes to be observed in chronic laminitis, we take up the description where we left it when dealing with the pathological anatomy of the acute form. The alterations to be met with are best observed by taking a foot so diseased and making of it two sections—one longitudinal, from before backwards; the other horizontal, and in such a position as to cut the os pedis through at its centre.
These sections will expose to view the cavity formed by the pouring out of the exudate, and its full extent may be noticed by examining the sections alternately. Taking the horizontal section first, it will be seen that the hollow space extends wholly round the toe, and as far back as the commencement of the quarters. In the latter position one is able to observe laminæ still in their normal positions and condition. At the toe, however, the horny and secretive laminæ are widely separated, and the space between them filled with a yellow, semi-solid material, the remains of the inflammatory exudate and new horn secreted by the keratogenous membrane. The laminæ, both horny and sensitive, are greatly enlarged. This is a hypertrophy, resulting from the continued effects of the inflammation, and leads in time to the formation of laminæ quite three or four times their normal size. It is this hypertrophy of the laminæ and the pressure of the exudate that causes the bulging and increased growth of the horn at the toe (see Fig. 125), and contributes towards the oval formation of the foot we have mentioned before.
LONGITUDINAL SECTION OF A FOOT WITH LAMINITIS OF SEVERAL YEARS' DURATION.
FIG. 125.—LONGITUDINAL SECTION OF A FOOT WITH LAMINITIS OF SEVERAL YEARS' DURATION.
In the longitudinal section the first thing noticeable is the change in position of the bones, more especially in that of the os pedis. The circumstances we have mentioned before—pressure of the exudate upon it in front and tension of the perforans on it behind—have caused it to assume a more upright position than is normal, so much so that in a bad case the front of the bone becomes quite vertical. This vicious direction the other bones of the digit follow (see Fig. 125).
Consequent upon the displacement of the bone, the plantar cushion, by reason of the continued pressure thus put upon it, becomes atrophied, while its hinder half is, as it were, squeezed into taking up a position more posterior and higher in the digit than normally it should. The horn-secreting papillæ covering its inferior face thus become directed backwards sooner than downwards, in which way we account in some measure for the noticeable increase of horn at the heels.
Treatment.—Chronic laminitis is incurable. Treatment must therefore be directed towards the palliation of such conditions as are present, with the object of rendering the the animal better able to perform work. When perforation of the sole has occurred, with the attendant formation of pus and necrosis of the os pedis, it is doubtful whether treatment of any kind is advisable. There are on record cases of this description, where careful curetting of the exposed and necrotic portions and the after application of antiseptic dressings, held in position by a plate shoe or a leather sole, has been followed by good results, and the animal restored for a time to labour. In our opinion, however, early slaughter is the most economical course to adopt, and certainly the wisest advice to give to the ordinary client.
When perforation of the sole is absent, and when serious alteration in the shape of the horny box has not occurred, then the most simple treatment is to put the animal straight away to slow work, with the feet protected by suitable shoes.
Here, again, the most useful shoe is the Rocker Bar (Fig. 119). The broad web and deep seating gives ample protection to the convex sole, and with the ease in distributing his weight that this shoe affords the animal is able to perform slow work on soft lands with some degree of comfort.
Should the growth of the horn at the toe and at the heels be unduly excessive, then our attention may be directed towards reducing it to some approach to the normal. This is accomplished by removing with the rasp and the knife those portions indicated by the dotted lines in Fig. 127. Here it will be seen that the bulk of the horn removed is that protruding at the toe. After this the animal should again be suitably shod. In this connection it should be noted that the fact of the animal walking largely on the heels tends to a forward displacement of the shoe. This must be prevented by providing each heel of the shoe with a clip, after the manner shown in Fig. 128; or, in the case of a bar shoe, supplying it with a clip at the centre of the bar.
DIAGRAM ILLUSTRATING THE ABNORMAL GROWTH OF HORN AT THE TOE AND HEELS OF THE FOOT WITH CHRONIC LAMINITIS.
FIG. 126.—DIAGRAM ILLUSTRATING THE ABNORMAL GROWTH OF HORN AT THE TOE AND HEELS OF THE FOOT WITH CHRONIC LAMINITIS.
THE SAME FOOT AS IN FIG. 126.
FIG. 127.—THE SAME FOOT AS IN FIG. 126. The dotted lines show the excess of horn removed preparatory to shoeing.
Among other treatments to be noted we may mention one or two to be found chiefly in Continental works on this subject.
The method of Gross consists in thinning down with a rasp about 1-1/2 inches of the horn of the wall immediately below the coronet, the thinned portion extending from heel to heel. The groove made is filled with basilicon ointment,[A] and the coronet stimulated with a cantharides ointment, In this way there is induced to grow from the coronet a new wall of nearly normal dimensions.
[Footnote A: Basilicon ointment is made by heating together resin 8 parts, beeswax 8 parts, olive oil 8 parts, and lard 6 parts. Allow to cool without stirring.]
By other operators (Bayer, Imminger, Meyer, and Gunther) this treatment has been modified by enlarging upon it and removing the whole of the adventitious horn.
THE SHOE WITH HEEL-CLIP.
FIG. 128.—THE SHOE WITH HEEL-CLIP.
This is done by means of the drawing-knife and the rasp, the ugly-looking pumiced foot being carefully cut and trimmed until, so far as outward appearances are concerned, it is perfectly normal. This done, the whole foot is treated with a suitable hoof ointment, and a shoe applied that affords protection to the sole without imposing pressure upon it. The shoe indicated is either an ordinary shoe with an unusually broad and well-seated web, or the seated Rocker Bar of Broad. With either it is well to additionally protect the sole by means of a leather or rubber pad and tar stopping, or by using the Huflederkitt described on p. 148. In every case the nails must be kept well back in order to avoid the weakened and degenerated horn at the toe, and to take advantage of the greater growth of horn at the heels.
The wisdom of thus removing the whole of the adventitious horn may be questioned. Although a foot of a nearly normal shape is obtained, it must be remembered that the grave alterations within it are unchanged, and that in certain positions the operation must have carried us nearer the sensitive structures than is advisable.
All other treatments failing, the operation of neurectomy has been advised. This we do not think wise. One would imagine that, with degenerative processes already going on in the foot, the tendency to gelatinous degeneration, always to be looked for in neurectomy, would be increased. This, as a matter of fact, is the case, and is borne out by the statements of those who have tried this method of treatment. In many cases the lameness even is not got rid of. Even where it is, the operation is afterwards followed by a great tendency to stumble, by sloughing of the hoof, or by a marked increase in the adventitious horn, and a consequent greater deformity of the foot.
Sooner than risk neurectomy, it seems to us wiser to give a trial to the operation advocated by M.G. Joly, namely, that of ligaturing one of the digital arteries on each affected foot. This operation is performed in the same position as is the higher operation of plantar neurectomy, and may be either internal or external. The vessel is exposed, and a double ligature, preferably of silk, placed on it. The artery is then divided between the two ligatures. The immediate effect of the operation is to cause a considerable diminution in the arterial pressure, and so lessen the intensity of the ostitis in the os pedis. Its consequences are not so serious as those of neurectomy, and it decongests tissues which neurectomy congests.
In cases related by M. Joly this operation, practised both in conjunction with removal of the excess of horn and without it, has resulted in a marked improvement in the gait, the animal going to work one month after the treatment, and remaining sound for some time afterwards.
2. SEEDY-TOE.
Definition.—A defect in the horn of the wall, usually at the toe, but occurring elsewhere, resulting in loss of its substance in either its internal or external layers (see Figs. 129, 130, and 131).
Causes.—The most common factor in the causation of this defect is undoubtedly disease of the sensitive laminæ. We have, in fact, just given an excellent example of the formation of a seedy-toe in the sections of this chapter devoted to laminitis (see pp. 265 and 286). The cavity here formed by the outpouring of the inflammatory exudate and the separation of the sensitive and horny laminæ persists. It becomes filled with the dried remains of the exudate and perverted secretions from the horny and sensitive laminæ (see p. 287). As yet, however, the cavity is closed below, and its existence only surmised. Later, with successive visits to the forge, the layer of solar horn forming its floor is cut away, and the cavity exposed to view. Its mealy-looking contents are removed, and the case reported by the smith.
Although occurring in this way with an acute attack of laminitis, it must be remembered that seedy-toe may arise without previous noticeable cause. The first intimation the owner has is a report from the forge that seedy-toe is in existence. To refer to cases so arising a probable cause is far from easy. At one time it was believed to be due to parasitic infection of the horn. Others have blamed the pressure of the toe-clip, excessive hammering of the wall, or pressure from nails too large or driven too close. Others, again, say that seedy-toe may result from a prick in the forge, from hot-fitting of the shoe, from standing on a dry and sandy soil, or from the use of high calkins on the front shoes. In these cases—cases with an insidious onset—we are inclined to the opinion that the disease of the horn commences from below, and that the sensitive laminæ become implicated later. Holding this view, one must account for the commencing disease of the horn by giving, as causes, firstly, those factors (as, for instance, alternate excessive dampness and dryness) leading to disintegration of the horn tubules; secondly, the penetrating into and between the degenerated tubules of parasitic matter from the ground; and, thirdly, the final breaking up of the horn, and spread of the lesion under the invasion thus started.
DIAGRAM ILLUSTRATING POSITION OF SEEDY-TOE (INTERNAL).
FIG. 129.—DIAGRAM ILLUSTRATING POSITION OF SEEDY-TOE (INTERNAL). 1, The horn of the wall; 2, the horn of the sole; 3, the cavity of the seedy-toe; 4, the os pedis; 5, the keratogenous membrane.
Symptoms.—Lameness sometimes attends seedy-toe, and sometimes does not. This is an important point to be carried in mind by the veterinary surgeon who is accustomed in his practice to have many animals pass through his hands for examination as to soundness. An animal with advanced seedy-toe—a condition constituting serious unsoundness—may walk and trot absolutely sound, and may give no indication, either in the shape of the wall or the condition of the sole, that anything abnormal is in existence. Later, however, after the veterinary surgeon has passed him, the purchaser lodges the complaint that the horse has a bad seedy-toe, which, so he is told, must have been there for some time. In this case, culpable though he may appear, there is every excuse for the veterinary surgeon.
Once the cavity is opened at the toe in the neighbourhood of the white line, then diagnosis is easy. A blunt piece of wood, the farrier's knife, or a director may be easily passed into it, sometimes as far up as the coronary cushion (see Fig. 129). Issuing from the opening is seen occasionally a little inspissated pus; more often, however, the dry, mealy-looking detritus to which we have before referred. This form of the disease we may term 'Internal Seedy-Toe.' for, plainly enough, it has had its origin in chronic inflammatory changes in the keratogenous membrane.
EXTERNAL SEEDY-TOE COMMENCING AT THE PLANTAR BORDER OF THE WALL.
FIG. 130.—EXTERNAL SEEDY-TOE COMMENCING AT THE PLANTAR BORDER OF THE WALL.
EXTERNAL SEEDY-TOE COMMENCING ON THE ANTERIOR FACE OF THE WALL.
FIG. 131.—EXTERNAL SEEDY-TOE COMMENCING ON THE ANTERIOR FACE OF THE WALL.
Disease of the horn and loss of its substance may, however, also commence from without. A report on this condition, under the title of 'External Seedy-Toe,' is to be found in vol. xxix. of theVeterinary Journal, from which we borrow Figs. 130 and 131.
In Fig. 130 it will be seen that the disease commences at the plantar surface of the toe, and extends upwards and inwards. The same condition may also appear anywhere between the coronet and the ground, gradually extending into the substance of the wall, as shown in Fig. 131. According to the writer, Colonel Nunn, the progress of the disease in this latter case appears to be faster in a downward than in an upward direction. This, however, is more apparent than real, as the rate of growth of the horn downwards detracts from the progress of the disease upwards, although it spreads over the horn at the same rate.
Before concluding the symptoms, we may again allude to the fact that, although usually occurring at the toe, the same condition may be met with in other positions—namely, at either of the quarters. In appearance and in other respects it is identical with that occurring at the toe.
When the animal is lame and the existence of seedy-toe is surmised, or when the cause of the lameness is altogether obscure, a little information may perhaps be gathered from noting the wear of the shoe. If the animal has been going lame for any length of time as a result of disease in the sensitive laminæ, then the shoe will be greatly thinned at the heels, and the toe but little worn.
Treatment.—As with diseased structures elsewhere, the most rational treatment, when possible, is that of excision. The entire portion of the wall forming the anterior boundary of the cavity is thinned down with the rasp and afterwards removed with the knife, wholly exposing the hypertrophied, but usually soft layer of horn covering the sensitive structures. These hypertrophied portions are also removed, and every particle of the dust-like detritus cleaned away. After-treatment consists in dressing the parts with a good hoof ointment, protecting them, if necessary, with a pad of tow and a stout bandage. It may be that the removal of a large portion of the wall may for some time throw the animal out of work. Acting on Colonel Fred Smith's suggestion, this may be avoided by having made a thin plate of sheet-iron, slightly larger in circumference than the portion of horn removed, and shaped to follow the contour of the foot. This made, it is sunk flush with the wall by hot-fitting it, and kept in position by several small steel screws fixed into the sound horn, just as in the treatment for sand-crack (see p. 174). This will serve the useful purpose of maintaining in position any dressing that may be thought necessary, of acting as a support to the horn left on each side of the portion removed, and of keeping the exposed structures free from dirt and grit.
Practical points to be remembered in fitting plates of this description to the feet are: The plate must never quite reach the shoe, or it will participate in the concussion of progression, and so loosen the screws that hold it in place. For the same reason, that portion of the sole adjoining the piece of horn removed must have its bearing on the shoe relieved. The screws holding the plate should be oiled to prevent rusting, and should take an oblique direction in order to obtain as great a hold as possible on the wall.
When excision is deemed unwise or unnecessary, treatment should be directed towards maintaining the cavity in a state of asepsis. To this end it should be thoroughly cleaned of its contents, and afterwards dressed with medicated tow. The ordinary tar and grease stopping is as suitable as any. This, together with the tow, is tightly plugged into the opening and kept in position by a wide-webbed shoe. Instead of the tar stopping and the tow, there may be used with advantage the artificial hoof-horn of Defay (see p. 152). Before using this the cavity should again be thoroughly cleaned out, and should in addition be mopped out with ether. The latter injunction is important, as unless the grease is thus first removed, the composition will fail to adhere to the horn. With the cavity thus cleaned and prepared, the artificial horn, melted ready to hand, is poured into it and allowed to set.
In every case, no matter what else the treatment, the bearing of the horn adjacent to the lesion should be removed from the shoe. Whether practising the method of plugging the cavity or that of excision of the wall external to it, attempts to quickly obtain a new growth of horn from the coronet should be made. To further that, frequent stimulant applications should be used. Ointment of Biniodide of Mercury 1 in 8, of Cantharides 1 in 8, or the ordinary Oil of Cantharides, either will serve.
3. KERAPHYLLOCELE.
Definition.—By this term is indicated an enlargement forming on the inner surface of the wall. In shape and extent these enlargements vary. Usually they are rounded and extend from the coronary cushion to the sole, sometimes only as thick as an ordinary goose-quill, at other times reaching the size of one's finger. Often they are irregular in formation and flattened from side to side.
A PORTION OF THE HORN OF THE WALL AT THE TOE REMOVED IN ORDER TO SHOW A KERAPHYLLOCELE ON ITS INNER SURFACE.
FIG. 132.—A PORTION OF THE HORN OF THE WALL AT THE TOE REMOVED IN ORDER TO SHOW A KERAPHYLLOCELE ON ITS INNER SURFACE.
Causes.—Keraphyllocele is very often a sequel to the changes occurring at the toe in laminitis. Probably, however, the most common cause is an injury upon, or a crack through, the wall. It may thus occur from excessive hammering of the foot, from violent kicking against a wall or the stable fittings, and from the injury to the coronet known as 'tread.' It may also occur as a sequel to complicated sand-crack, and to chronic corn.
That fissures in the wall are undoubtedly a cause has been placed on record by the late Professor Walley, who noticed the appearance of these horny growths following upon the operation of grooving the wall.[A]
[Footnote A:Journal of Comparative Pathology and Therapeutics, vol. iii, p. 170.]
This gentleman had a large Clydesdale horse under his care for a bad sand-crack in front of the near hind-foot, and, as the lameness was extreme, he adopted his usual method of treatment—viz., rest, fomentations, poulticing, and the making of the V-shaped section through the wall, and subsequently the application of an appropriate bar shoe to the foot, and repeated blisters to the coronet. In a short time the lameness passed off, and the horse was put to work. A few days later the animal met with an accident, and was killed.
On examining a section of the hoof it was found that a vertical horny ridge corresponding to the external fissure had been formed on the internal surface of the wall, and that a well-marked cicatrix extended upwards through the structure of the hoof at the part forming the cutigeral groove; furthermore,a similar ingrowth had been taking place in the line of the oblique incisions made for the relief of the sand-crack.
This case has an important bearing on the operation of grooving the wall, which operation we have several times in this work advocated for the relief of other diseases. It teaches us that the incisions should not be carried so completely through the horn as to interfere with and irritate the sensitive laminæ, and so set up the chronic inflammatory condition leading to hypertrophy of the horn.
From the position on the os pedis of the indentation made in it by the keraphyllocele (see Fig. 133) it has been argued that pressure of the toe-clip is a cause of the new growth. This, we should say, cannot be a very strong factor in the causation, for, while we admit that the continual pressure of the clip, and the heavy hammering that sometimes fits it into position, is likely to set up a chronic inflammatory condition of the sensitive laminæ in that region, we must still point out that the rarity of keraphyllocele, as compared with the fact that clips are on every shoe, does not allow of the argument carrying any great weight.
Symptoms.—Except under certain conditions this defect is difficult of detection. As a rule, lameness is not produced by it. In making that statement we are led largely by the conclusion arrived at by Professor Walley. This observer noted the fact that ingrowths of horn such as we are describing nearly always take place in false quarter, or after a sand-crack has been repaired, and that they commonly occur after the operation of grooving the wall in the manner we have just shown.
Now, we know that quite often under these circumstances the horse goes perfectly sound. Thus, while we know that in all probability keraphyllocele is in existence, we have ocular demonstration that the animal is quite unaffected by it.
In some cases, however, lameness is present. During the early stages of the growth's formation it is but slight, increasing as the keraphyllocele enlarges. Should this be the case, other symptoms present themselves. The coronet is hot, and tender to the touch, sometimes even perceptibly swollen, and percussion over the wail is met with flinching on the part of the animal. In other cases one is led to suspect the condition by the prominence of the horn of the wall of the toe. This is distinctly ridge-like from the coronet to the ground, while on either side of it the quarters appear to have sunk to less than their normal dimensions. We believe this to be an illusion, as a ridge of any size at the toe readily gives one the impression of atrophy behind it, without this latter condition being actually present.
Should this ridge-like formation and the accompanying symptoms of pain and lameness occur after repair of a sand-crack, then keraphyllocele may, with tolerable certainty, be diagnosed. When these outward signs are wanting, however, and the true nature of our case is a matter of mere conjecture, a positive diagnosis may still be made at a later stage—that is, when the abnormal growth of horn reaches the sole. In this case either there is met with when paring the sole a small portion of horn, circular in form, distinctly harder than normal, and indenting in a semicircular fashion the front of the white line at the toe, or solution of continuity between the tumour and the edge of the sole and the os pedis takes place, and the lameness resulting from the ingress of dirt and grit thus allowed draws attention to the case.
Pathological Anatomy.—With the sensitive structures removed from the hoof by maceration or other means, these growths are at once apparent. They may occur in any position, but are usually seen at the toe, and they may extend from the coronary cushion to the sole, or they may occupy only the lower or the upper half of the wall. In places the tumour (or 'horny pillar' as the Germans term it) is roughened by offshoots from it, and does not always exhibit the smooth surface depicted in Fig. 132. Commonly, the horn composing the new growth is hard and dense. Sometimes, however, it is soft to the knife, and is then found to be itself fistulous in character, a distinct cavity running up its centre, from which issues a black and offensive pus.
In a few cases the sensitive laminæ in the immediate neighbourhood are found to be enlarged, but in the majority of cases atrophy is the condition to be observed. Not only are the sensitive structures found to be shrunken and absorbed, but the atrophy and absorption extends even to the bone itself (see Fig. 133). This latter is a result of the continued pressure of the horny growth, in a well-marked case ending in a sharply-defined groove in the os pedis in which the keraphyllocele rests. The fact that the softer structures, and even the bone, thus accommodate themselves to the altered conditions is, no doubt, the reason that lameness in many of these cases is absent.
Treatment.—It is doubtful whether anything satisfactory can be recommended. When we have suspected this condition ourselves, it has been our practice to groove the hoof on either side of the toe, after the manner illustrated in Fig. 120, and, at the same time, point-firing the coronet and applying a smart cantharides blister. Certainly, after this operation, lameness has often disappeared—whether, however, as a result of the treatment adopted or by reason of the structures within accommodating themselves to the condition, we would not care to say.