Diseases of the Horse's Foot
by
Harry Caulton Reeks
Part 6 out of 8
Further, it is well to note that, although playing no part in the actual
causation, certain constitutional conditions may in some measure predispose
the foot to attack. Clinical observation teaches us that animals of a
lymphatic nature, with thick skins and an abundance of hair, with flat feet
and thick, fleshy frogs, are far more liable to attack than are animals
with reverse points.
_Exciting Causes_. Those who give this subject careful consideration cannot
fail to arrive at the conclusion that canker is most certainly due to local
infection with a specific poison, and that poison a germicidal one from the
ground. The symptoms arising may be due to the action of a single germ, or
to two or more germs acting in conjunction. As to whether the parasitic
invasion is single or multiple we cannot feel certain, but that it _is_
parasitic we feel absolutely assured.
It is simply the light that bacteriological advance has made during the
last two decades that enables us to make the statement with such feelings
of assurance. We arrive at our conclusions by reasoning from analogy.
Here we have a disease always exhibiting the same symptoms, more or less
peculiar to one class of animal, always with a similar characteristic
appearance and smell, always obstinately refractory to treatment, showing
always a tendency to spread to the other feet of the same animal, and often
to the feet of other animals _near enough to become_ infected, and always
cured--when cured it is--by a treatment which may be summed up in two words
as 'rigid antisepsis.' Other diseases, with points in common with this,
have been directly proved to be due to a specific cause. Common regard for
logic compels us to admit the same for canker.
[Illustration: FIG. 134.--A FOOT, THE SUBJECT OF CANKER, SHOWING
DESTRUCTION OF THE HORNY FROG, AND A FUNGOID-LOOKING HYPERTROPHY OF THE
TISSUES BENEATH.]
_Symptoms and Pathological Anatomy_.--The symptoms of canker are seldom
noticeable at the commencement of an attack. The disease is slow in its
progress; for some time confines its ravages to the sub-horny tissues
unseen, and is quite unattended with pain. It is not observed, therefore,
until considerable damage has been done, and the disease is far advanced.
What is usually first seen is a peculiar softening and raising of the horn
of the frog. The infective material has set up a chronic inflammation of
the keratogenous membrane, leading to abnormal secretion, and, in place of
the horny cells it should normally secrete, is thrown out an abundance of a
serous fluid.
This upraised and softened horn once thrown off is not again renewed, and
the whole of the sensitive frog and perhaps a portion of the sensitive sole
is left uncovered. In place of the normal horn, however, is often found a
hypertrophy of the elements of the keratogenous membrane leading to huge
fungoid-looking growths with a papillomatous aspect, damp in appearance and
offensive in smell, and readily bleeding when injured (see Fig. 131).
The horn immediately surrounding the lesion is loose and non-adherent to
the sensitive structures. This indicates, of course, that the disease has
spread further beneath the horny covering than is at first sight apparent.
Portions of this loose horn removed reveal beneath it a caseous foetid
matter, easily removed by scraping (the perverted secretion of the
keratogenous membrane). When this is carefully scraped away, the sensitive
structures appear to be covered with a thin, smooth membrane, gray in
colour and almost transparent, while beneath it may be seen the red
appearance of normal sensitive structures.
If the horn surrounding the lesion is not touched with the knife, but
little is seen of the extent of the disease, for that removed by natural
means is often very small in quantity. To all intents and purposes the
disease appears to be confined to the frog. This appearance is misleading,
especially if the disease has been in existence for some time, for it
may have easily spread to the whole of the sole, and even to the greater
portions of the laminae secreting the wall.
It is, in fact, not until the pressure exerted by the normal horn
is removed by its breaking away that the vascular structures of the
keratogenous membrane begin to swell, and the perverted secretions to
enlarge in size. Once the pressure is removed, however, this quickly
comes about, and the characteristic fungoid growths rapidly make their
appearance.
This tendency to spread is highly indicative of canker. The serous matter
exuding from the diseased keratogenous membrane appears, in fact, to be
highly infective. Once its flow is commenced, it slowly, but surely,
invades the sensitive structures near it, appearing, as Elaine has put it,
to 'inoculate' them. What is really the case, of course, is not that the
discharge itself is infective, but that it is contaminated with infective
material.
The fungoid-looking growths to which we have before referred are, in
reality, nothing more than the villi of the sensitive frog and sole greatly
hypertrophied and irregular in shape. At times the hypertrophy is as a huge
and compact enlargement occupying the position of the frog. Sometimes,
however, it occurs as numerous elongated and twisted fibrous bundles,
separated from each other by deep clefts, and the clefts filled with the
offensive cankerous discharge (see Fig. 134).
[Illustration: FIG. 135.--LOWER ASPECT OF CANKERED FOOT, SHOWING
DESTRUCTION OF WALL.]
At a very advanced stage canker leads to destruction of much of the horny
sole and frog; or even parts of the wall may become separated from the
tissues beneath, and break away from the foot (see Fig. 135). At other
times the disease brings about a deformity of the whole of the foot. Its
longitudinal and transverse diameters become enormously increased, and the
whole foot apparently flattened from above to below (see Fig. 136). This
indicates that not only has the horny sole been entirely destroyed, but
that the destructive process has also extended to the greater part of the
lower half of the wall, with a consequent hypertrophy of exposed soft
structures, and a sinking of the bony column, similar to that which occurs
in laminitis, but not so pronounced.
[Illustration: FIG. 136.--FOOT WITH ADVANCED CANKER.]
A further aspect of the badly-cankered foot is to be found in an apparently
enormous increase in the length of the wall. This we have seen protruding
for quite 5 inches beyond the plane of the sole. It simply indicates that,
in order to keep the animal at work, the smith has at every shoeing spared
the wall, so that the diseased structures might be kept from contact with
the ground.
As we have said before, pain and other symptoms of distress are quite
absent. Animals affected with canker for a long time maintain their
condition, feed well, and are quite capable of performing work under
ordinary conditions.
_Differential Diagnosis and Prognosis_.--Perhaps the only disease with
which canker may be confounded is thrush. They should, however, be easily
distinguishable. The discharge from thrush is not so profuse, and is
thicker and darker in colour, while the loosening of the horn is almost
entirely absent. Furthermore, thrush shows no tendency to spread, and, even
when left untreated, may remain confined to the frog for months, and even
years. Canker, on the other hand, is slowly progressive, and soon shows the
characteristic fungoid excresences, which growths are in thrush never seen.
A further point of difference is discovered when treatment is commenced.
Canker is found to be refractory to a point that is absolutely
disheartening, while thrush, with careful attention, is soon got under
hand, and a permanent cure effected.
The prognosis must be guarded. By many canker has been said to be
incurable. This, however, has been clearly shown to be wrong. When the
animal is young, and treatment may reasonably be judged to be economical,
then a favourable prognosis may be indulged in, provided the veterinary
surgeon intends to put into that treatment a more than ordinary amount of
individual care and attendance. Even then, however, he will have to be very
largely guided by the condition of his case. He should see that it is
not too far advanced, and that a great deformity of the hoof, or actual
exploration, does not indicate disease of the greater part of the wall.
_Treatment_.--From what has gone before, it will be seen that the
eradication of canker is no easy task, that it is, in fact, a most
difficult matter, and one not to be lightly undertaken. At the risk of
recapitulating what we have said before, we may mention here the two points
which the veterinarian must bear in mind. (1) That there is no actual
disease or alteration in structure of the deep layers of the keratogenous
apparatus. It is only the superficial, or horn-secreting, layer that
concerns us. (2) That the disease of this superficial layer is infection
with a material that may reasonably be presumed to be infective.
Put thus, treatment of canker would at first sight appear to be easy. One
would imagine that a simple and long-continued soaking of the entire foot
in a strong enough antiseptic would be all that was needed. Clinical
observation, however, shows that this is not so, and for this there must be
reasons.
The reasons are these: (1) Between us and the diseased layer upon which our
attention must be directed is often a layer of normal horn, effectually
protecting the tissues beneath from any dressing which we might consider
beneficial. (2) Anything applied with the object of destroying septic
material, but strong enough, or caustic enough, to injure the membrane upon
which we are working, only makes the case worse. The superficial layer of
the keratogenous membrane in which we have judged the disease to exist is,
after all, but a delicate structure. When attacked by the application of
too potent a drug its horn-secreting layer is easily destroyed, and thus,
although we may succeed in establishing asepsis, we cannot expect at the
point of injury a growth of horn. In its place we are confronted with large
outgrowths of inflammatory fibrous tissue. (3) Shedding of the diseased
horn and removal of the pressure exerted by the hoof faces us with
hypertrophy of the exposed villi. The difficulty of meeting this with an
adequate and evenly-distributed pressure is well enough known, and we find
in that a further reason that the treatment of canker is superlatively
difficult. (4) The material on which the animal has to stand is a distinct
bar to the maintaining of a strict asepsis.
When we have said this, it is easy to understand that canker is not to be
successfully met with any so-called specific--that it makes but little
difference what the application may be so long as it is antiseptic, and is
used by a man thoroughly conversant with the difficulties he has to contend
with, and with his mind firmly set upon surmounting them.
With this point established, we will not devote more of our space to a
consideration of the various dressings that have at different times been
highly advocated in the treatment of the disease. It is interesting,
however, to note that intensely irritating and caustic applications have
been greatly in favour. Nitric acid, sulphuric acid (either alone or its
action reduced by the addition of alcohol, oil, or turpentine), arsenic,
butter of antimony, creasote, chromic acid, carbolic acid, arsenite of
soda, and the actual cautery, have all been used.
Without dwelling further on that, we may say at once that a correct
treatment consists in (1) the removal of all horn overlying infected
portions of the keratogenous membrane, (2) the application of an antiseptic
not too powerfully caustic in its action, (3) frequent changes of the
dressings in order to insure a maintenance of antisepsis, and (4) the
application of an adequate pressure to the exposed soft structures. Thus
combated, canker is curable.
The man who, at the expense of much time and trouble, has demonstrated the
truth of these axioms is Mr. Malcolm, of Birmingham. The determination with
which he clung to his point that canker was, with correct treatment, in
every case curable, was some years ago provocative of much discussion in
veterinary circles. That he was successful in proving his contention is
more to our point here. It is his method of treatment, therefore, that we
shall give, and this we shall do by liberal extracts from Mr. Malcolm's own
writings.
'On the first occasion of operating upon and dressing the cankered foot,
it is usually necessary to cast the horse, and this may have to be done
at intervals for a second or even third time; but in most cases once is
sufficient, subsequent dressing being usually accomplished without much
difficulty, frequently even without the aid of a twitch. After the horse
has been secured, the drawing-knife is first employed; and if the frog
alone is affected, it is unnecessary even to pare the sole, the removal of
all frog horn not intimately adherent to its secreting surface being all
that is required. But if both sole and frog be involved, the whole of the
sound horn should be first thinned until it springs under the thumb,
and then, using a sharp knife, every particle of diseased horn must be
carefully removed from both sole and frog, a process much more easily, and
with far greater certainty, secured by the previous thinning of the horn.
'The removal of diseased horn should always commence at the most dependent
part of the foot, so that any haemorrhage produced may be below the parts
still to be operated on, a matter of considerable moment for effective
treatment. But with due care there will be little haemorrhage, as, except in
the initial stage, there is no real union between the diseased horn and the
diseased vascular secreting surface.
'After all apparently diseased horn has been removed by the knife, any
still remaining should be at once destroyed by the actual cautery, by
which it can be identified. All the diseased secreting surface should be
_carefully scraped with a thin hot iron_,[A] fungoid growths excised and
cauterized, and, indeed, every particle of cankered tissue should, if
possible, be eradicated. In securing this more reliance can be placed on
the actual cautery than on any other, whether liquid or solid: it is more
under control in application, more decisive in effect, and its results can
be anticipated with a far greater certainty. Moreover, its aid in diagnosis
is of immense value; applied to the thinned horn or secreting surface it
unmistakably demonstrates the presence or absence of canker. Healthy tissue
chars black; cankered tissue, on the contrary, bubbles up white under the
hot iron, and presents an appearance not unlike roasted cheese.
'Although this test is certain for horn thinned to the quick, it is not to
be relied upon with thick horn, the outside of which may be practically
healthy and char black, while its underlying surface may be cankered. With
this exception the test is an infallible one, as by it the demarcation
between cankered and healthy tissue can be clearly traced, and as a result
we can with equal confidence radically _remove_[A] all cankered tissue, and
conserve all healthy. As the object of that abominably cruel and barbarous
operation of stripping the sole is the exposure of all canker, and as this
can be done with equal certainty with the aid of the hot iron, there can be
no necessity for performing it. The pain of cauterizing cankered tissue,
which is a necessary operation, is infinitesimal (canker largely destroying
sensation), compared with the pain produced in the totally unnecessary
process of tearing healthy horn from a highly sensitive tissue.
[Footnote A: The words in italics are alterations in the original article
made by Mr. Malcolm in a private letter to the author (H.C.K.).]
'Having by means of the knife and cautery removed every known particle of
disease, the next procedure is to pack the surface of the sole and frog
thus exposed with a _mild dressing, such as vaseline; but if the cankered
surface has not been efficiently, scraped, than there is required a more_
[A] powerful astringent or caustic dressing, which may vary considerably
according to the individual fancy. A great favourite of mine consists of
equal parts of sulphates of copper, iron, and zinc, mixed with strong
carbolic acid, a very little vaseline being added to give the mass
cohesion. The dressing, covered by a pledget of tow, is held in position
by a shoe with an iron or leather sole, and the dressing and tow together
should be of sufficient bulk to produce slight pressure on the sole when
the nails of the shoe are drawn up. This insures contact between the
dressing and the exposed surface, as well as any benefit derivable from
pressure.
[Footnote A: The words in italics are alterations in the original article
made by Mr. Malcolm in a private letter to the author (H.C.E.).]
'The dressing of the foot and nailing of the shoe can usually be more
expeditiously performed when the horse is on his feet than when prone. If
only the frog, or the frog and a small part of the sole, be involved, the
horse should be kept at work, but if a large part or the whole of the sole
a few days' rest may be necessary; but as soon as the condition of the foot
will allow, work should be resumed, and it is simply marvellous how sound a
horse will walk while minus the greater part of his sole from canker.
'On the second day following the shoe should be removed, and the foot
redressed. To effect this it is necessary to recast the horse. Commencing
at the edge of the sound horn, at the most dependent part of the foot,
all new horn, no matter what its condition, must be pared to the quick,
especial care being taken to effectually remove any lingering disease. Want
of success is frequently attributable to neglect of this precaution.
A small particle of canker remains undetected, forms a new centre of
infection, and just when success is anticipated, much to your chagrin you
have to deal with a fresh outbreak of canker, instead of a rapidly-healing
foot. Parenthetically, I may here remark that the amount of more or less
imperfect new horn produced by a cankered surface after an effective but
not too destructive cauterization is almost incredible, and one cannot fail
to be struck with the very active proliferation here compared with the
meagre production of new horn by the healthy surface.
'After all disease has been excised, carefully clean the foot with waste,
thoroughly protect any raw surface resulting from overcauterization by some
mild agent, such as a saturated calomel ointment, reapply an astringent
dressing over the whole affected surface, and nail on the shoe. This method
of procedure should now be thoroughly carried out daily for a time, and
as it is proceeded with a successful issue soon becomes assured in nearly
every case. Where, in spite of these efforts, the disease still persists,
depend upon it the fault is with the operator, who has failed to eradicate
some centre of infection. Under these circumstances it may be necessary
to recast the patient, repare the foot, and by the aid of eye, knife,
and cautery, endeavour to find the cause, and having found it, which can
invariably be done, remove it. The usual treatment will then speedily
become successful. As the case proceeds dressing every other day will
soon be sufficient, then twice a week, and finally, once a week until
sufficiently cured.
'During this healing process, and after the complete eradication of canker
it may be again repeated, no agent seems to have a more beneficial effect
than calomel, and for this purpose it is best used as a dry powder. Under
this dressing any remaining spot of canker is readily detected by the wet
condition of the calomel when the shoe is removed the next day. In dealing
with such a spot, a very good plan, after all apparently diseased tissue
has been excised, is to touch the cankered part with solid nitrate of
silver, or a feather dipped in one of the strong mineral acids, and
then reapply calomel over the surface. The result of this treatment is
frequently very gratifying.
'In successful treatment the shoe must be removed each time--an adjustable
plate will not do, as no man can thoroughly pare and examine a foot with
the shoe on, and imperfect dressings are worse than useless. Indeed, it is
better not to pare or thin the horn at all, than to imperfectly pare, since
canker, if undestroyed, develops far more rapidly under thin horn than
under thick.
'In conclusion, I would again urge the necessity, at the very first
operation, when the horse is down, of removing _every single particle_ of
the diseased tissue, either by excision or effectual cauterization, but at
the same time taking very great care to guard against the latter being
too destructive. The cautery should be laid aside as soon as the tissue
cauterized ceases to _burn white_. The moment at which the canker has
thus been eradicated without destroying sound tissue is indicated by
the appearance of healthy horn, by the intimate union of that with the
secreting surface, and by the healthy aspect of the exuded blood when
paring has been carried to the quick.
'Should subjacent healthy structures be destroyed during the process,
that is shown by the production of a raw sore, or of a sore to which a
"sit-fast," coextensive to the injury, is firmly attached. This seriously
retards recovery. The secreting surface having been destroyed, no new horn
can be produced directly from the part, and a new secreting surface and new
horn have now to grow inwards from the surrounding undestroyed tissue, and
that is a slow process. At the same time, on the principle of choosing
the least of two evils, practical experience teaches that it is better to
produce a small sore or a "sit-fast" than to leave a part of the canker
undetected; but, on the other hand, it is better to leave a small part
of canker undetected, which can be recognised and removed at the next
examination, than to cause a large slough. The object of the skilful
surgeon is, naturally, to avoid both extremes; and if trouble be taken to
carry out the procedure described, there need be no fear of the result.'[A]
[Footnote A: _Journal of Comparative Pathology and Therapeutics_, vol. iv.,
p. 24.]
Treated in this way, the horse with cankered feet may be usually kept at
work during the whole time that treatment is carried out, and a cure is
obtainable in periods varying from six weeks to six or even twelve months.
The same essentials in treatment--namely, removal of diseased horn,
antiseptic dressings, and pressure--are insisted on by other writers.
Bermbach,[A] in 1888, treats canker as follows: The horse having been cast,
the undermined hoof-horn is removed with the knife, and the hypertrophied
sensitive structures, if necessary, reduced in the same manner. The chief
difficulty in removing the latter is experienced in the lateral lacunae of
the frog, where it is most conveniently scraped away with a spoon or sharp
curette. Professors Hoffmann and Imminger also operate in the same way,
applying an Esmarch's haemostatic bandage, and using the knife and curette
freely.[B]
[Footnote A: _Ibid_., vol. ii., p. 68.]
[Footnote B: _Veterinary Journal_, vol. xxxv., p. 433.]
Haemorrhage is afterwards arrested, and a dressing of perchloride of mercury
(a solution, 1/2 per cent., in equal parts of alcohol and water) applied.
The after-dressings succeeding best are those of _slightly_ caustic and
astringent agents, preferably in the form of a powder, and held in position
by carbol-jute pads and linen bandages applied with a certain amount of
pressure.
The same author draws attention to the fact that caustic agents such as
nitrate of lead, chloride of zinc, etc., act too powerfully if the bleeding
has been arrested and the wound disinfected. They then form a thick crust,
under which profuse suppuration takes place. The same agents are likewise
contra-indicated when haemorrhage is still present. In this latter case
they combine with the blood to form metallic albuminates, which lie as an
impenetrable layer on the surface of the wound, and so hinder the action of
drugs on the tissue below.
During his after-treatment, Bermbach advocates removal of the dressings
every second day, all cheesy material to be scraped away with the knife,
and the sublimate lotion to be used again. He also insists on the animal
being kept standing in a _dry stable_,--nothing but a stone pavement kept
clean--and put to regular work in a plate shoe after the first or second
week. Cure of advanced cases is said to be obtainable in from four to six
weeks.
As illustrative of the value of pressure in the treatment of canker, we may
also draw attention to a treatment advocated by Lieutenant Rose.[A] This
observer holds that adequate pressure is unobtainable by packing the foot,
and, to obtain it, removes the wall from heel to heel, much after the
manner of preparing the foot for the Charlier shoe, so that the _whole_ of
the weight is taken by the sole and the frog. Tar and tow is then lightly
applied, the foot placed in a boot, and the patient turned into a
loose-box. The dressing is repeated at intervals of four or five days until
the animal is cured.
[Footnote A: _Veterinary Record_, vol. xi., p. 435.]
Those who have followed this method of treatment have modified it by
actually shoeing the animal Charlier fashion, and keeping him at work,
attention, of course, being at the same time given to a proper antiseptic
dressing.
_Reported Cases_.--1. (Malcolm's Treatment[A]). The subject was a five-year
old horse belonging to a client of Mr. Giver's, of Tamworth. The case was
an exceptionally bad one, for not only was the whole of the frog and sole
of the near hind-foot cankered, but the disease on the outside quarter
extended to within 1/2 inch of the coronet, and on the inside quarter to
within 2 inches of it. As the owner, a farmer, had not proper convenience
for Mr. Olver to treat the case, the latter asked me, while visiting him,
if I would care to undertake the treatment, saying at the time it would
be a very good test-case, as the disease was so far advanced. I readily
agreed, and, after the necessary arrangements, had the horse removed to
Birmingham on July 2. In this case it was found necessary to cast the
animal and cauterize the foot a second time before a healthy granulating
surface was secured; but after this the progress towards recovery was
uninterrupted, although necessarily slow, on account of the large amount of
new secreting surface which had to be formed.
[Footnote A: _Journal of Comparative Pathology and Therapeutics_, vol. v.,
p. 48.]
The horse was finally discharged, after inspection by Mr. Olver, absolutely
cured and free from canker, on January 7.
The illustration (Fig. 135, p. 312) is from a photograph, and it gives a
somewhat imperfect representation of the state of the foot two months after
it came under my care.
2. (Rose's Treatment.[A]) This was a bad case of canker, which had been for
two or three months treated in the ordinary manner, with but little sign
of ultimate success. Commenced in June and carried on until the end of
September, the ordinary treatment consisted in burning down the fungus
growth with the hot iron, and dressing with copper sulphate, zinc sulphate,
and boracic acid. The cauterization was repeated every five days.
[Footnote A: _Veterinary Record_, vol. xi., p. 435.]
The treatment of Lieutenant Rose was commenced at about the end of
September, at which date the disease extended from the toe on one side of
the foot right back to the heel, involving the sole, half of the frog, and
the bulb of the heel. One week after treatment the diseased surface was
drier, and granulations were more healthy. At the expiration of a fortnight
the new horn had commenced to grow from the wall, and also from the frog,
right round the diseased surface, the diseased part of the bulb of the heel
being divided from the sole by new horn.
Three to four weeks later the diseased surface was gradually getting
smaller, while in about six weeks it was quite healed up, the last place to
heal being a strip outside the bar, between it and the wall, and a smaller
spot on the bulb of the heel. These healed up simultaneously, and left the
animal sound.
3. (Treatment by Pressure, H. Leeney [A]). I was consulted in the early
part of last summer, before the dry weather had begun, as to a farm-horse
with canker in three feet. Her shoes were in the 'disgruntle' condition we
so often find on farms, that, to give her a level bearing until I should
call another day with a farrier to help me to pack the foot up in the
old-fashioned way, I had the remaining shoes pulled off. The case somehow
dropped out of my list, and I neglected to call, until asked one day to see
something else.
[Footnote A: _Veterinary Records_, vol. xi., p. 447]
I then found that, under a pressure of work, the animal had been used in
the shafts of a farm-cart on tolerably level ground, and when the dry
weather had already set in. There was a distinct improvement in all the
diseased feet, and as she was badly wanted I contented myself with rasping
off some broken crust, and supplied some caustic dressing for use at night.
Without shoes she worked continuously on the dry and hard meadow-land for
several weeks, and was practically cured in something less than three
months. My astringent or caustic lotion may have had something to do with
the cure of the deep-seated parts, but the bare recital of the case should
be sufficient to show that it is all a question of bearing, or nearly so.
7. SPECIFIC CORONITIS.
_Definition_.--In describing this condition under the above heading, we
are following the lead of Mr. Malcolm. We may define it as a chronic
inflammatory condition of the keratogenous membrane, usually confined to
that of the coronary cushion, the ergots and the chestnuts, but sometimes
extending to that of the frog and the sole, characterized by a malsecretion
of the affected membrane similar to that observed in canker.
_Causes_.--The cause which we have indicated for canker--namely, a local
specific one, is in all probability the one operating here. Apparently
there is a variance of opinion as to whether the condition is actually
canker or not. We think, however, that the character of the secretion of
the affected membranes, the appearance of the growths, the manner in which
they react to the hot iron, the comparative absence of pain, and other
points of similarity, point to the fact that the two conditions are
actually identical. In other words, the cause is precisely the same, and
the only point of difference is the alteration in the point of attack.
_Symptoms_.--Like canker, the disease is insidious in onset. In precisely
similar manner the horn, and in this case the skin of the coronet, is
underrun. Later there is the partial shedding and fissuring of the
undermined horn and the exuding of the characteristic discharge--in this
case not so watery as that of canker. The caseous material of canker is
also present, as is a disposition to hypertrophy of the exposed sensitive
structures. What horn is left becomes rough and irregularly fissured, and
has been likened by some observers to deeply-wrinkled bark of an old tree.
A peculiar characteristic of this condition is the state of the ergots and
chestnuts. Here the keratogenous membrane participates in the diseased
process, and their horn becomes dry and brittle, and readily splits into
small fibrous bundles very similar to the fibroid growth described in
canker. These excrescences are easily separated from the sensitive
structures beneath, and the exposed surface is seen to be more or less
moist, or even exhibiting a slight oozing of blood.
Again, as in canker, the deeper layers of the sensitive structures appear
to be normal, the horn-secreting layers being the only ones affected.
According to Malcolm, the disease is in its nature equally as inveterate as
canker, but it is easier to treat, on account of its more exposed position.
_Treatment_.--This is exactly that as described for canker.
[Illustration: FIG. 137.--SPECIFIC CORONITIS OF ALL FOUR FEET.]
[Illustration: FIG. 138.--OFF FORE-FOOT AFFECTED WITH SPECIFIC CORONITIS.]
_Recorded Case_.--The subject of this case was a young black cart gelding.
The disease is reported as having begun as thrush, and then extended to the
coronet. When I saw him he had been in a similar condition to that depicted
in Fig. 137 for, it was said, two or three months, the driver of the horse
meanwhile endeavouring to effect a cure by some potent drug of his own. The
animal was in good condition, but walked with difficulty owing to the pain.
The coronary bands were swollen to two or three times their natural size,
and this caused the hair immediately above to curl upwards. Just below the
coronary bands there was a line of separation between them and the wall.
They themselves were covered with the cheesy substance typical of canker,
and they bled on friction. Down the wall of the off fore-foot some blood
had trickled, which may be seen in Fig. 138. The frogs of all four feet
bulged backwards, and were badly affected. The soles were covered with
normal horn, but I did not resort to paring to see if they were affected.
One very curious feature about the case was the fact that all the
callosities (ergots and chestnuts) seemed to participate in the morbid
process, and they, too, were covered with a thin layer of soft cheesy horn.
The animal used to bite at his coronets and also the callosities above the
knees and hocks until they bled, which they did quite easily. The owner
would not go to the expense of having him treated, so he was destroyed.[A]
[Footnote A: Henry Taylor, _Veterinary Record_, vol. xvii., p. 311.]
CHAPTER X
DISEASES OF THE LATERAL CARTILAGES
A. WOUNDS OF THE CARTILAGES.
To a consideration of this we shall devote but little space. It is
sufficient to say that any wound in the region of the coronet should always
be given the most careful attention. More particularly should this be so
when it is ascertained that the wound has involved one of the lateral
cartilages. Wounds of non-vascular bodies such as these are always slow to
heal, and, by reason of their slowness, invite septic infection. In many
cases, in fact, it happens that they do not heal at all. Instead, the
injured part becomes necrotic, is unable to cast itself off, and remains as
a centre of infection in the depths of the wound, thus constituting what is
known as a quittor.
Apart from this, it will be remembered that the internal face of the
cartilage is in intimate contact with the pedal articulation, especially
anteriorly. Wounds in this situation are, therefore, likely to penetrate
the joint, giving us as a complication of the injury the conditions of
synovitis and arthritis.
Immediately a wound is inflicted in this position, attempts should be made
to insure thorough asepsis of the part. When possible, by far the better
way of accomplishing this will be to wholly immerse the foot in a tub of
cold antiseptic solution, and keep it there for an hour three times daily.
During the time the foot is out of the solution the wound should be
protected with a pad of carbolized tow or other suitable dressing, and
wrapped in a linen bandage or clean bag. If unable to use the bath, then
antiseptic solutions of more than moderate strength should be freely
applied to the wound and the adjacent parts, a carbolized or other
antiseptic pad placed over it, and the bandage adjusted as before. Repeated
injuries to the cartilages, even if not attended with an actual wound,
are apt to bring about their ossification and end in the formation of
side-bones.
B. QUITTOR.
_Definition_.--A fistulous wound of the foot, usually opening at the
coronet, and variously complicated according to the structures invaded by
its contained pus. For the reason that quittor is in every-day veterinary
nomenclature _usually_ associated with necrosis or other abnormal condition
of the lateral cartilage, we include its description in this chapter.
_Classification_.--It has been customary with Continental authors to
classify quittor according to the extent and position of the diseased
process. There were thus distinguished:
_(a)_ The _Simple_ or _Cutaneous Quittor_, in which had occurred nothing
more than necrosis of a portion of the coronary skin and the structures
immediately underlying it--that is, the superficial portion of the coronary
cushion.
_(b)_ The _Tendinous Quittor_, in which not only the immediately
subcutaneous tissues were attacked, but also portions of tendon and of
ligament.
_(c)_ The _Sub-horny Quittor_, in which the diseased process had invaded
the deeper portions of the coronary cushion, and continued a downward
course until the laminal tissue below the upper margin of the wall was
involved, or any other case, no matter what the starting-point, in which
pus existed within the horny box and was discharging itself by a fistulous
opening.
_(d)_ The _Cartilaginous Quittor_, in which a portion of the lateral
cartilage had become attacked and rendered necrotic.
We believe that--in this country, at any rate--the word 'quittor' is
usually held to indicate one or other of the two latter conditions, and
probably the last of these; and that the two first are held of small
account, or hardly of sufficient gravity to allow of the word 'quittor'
being applied to them. In fact, by defining quittor as a 'fistula,' or
little pipe, we have ourselves already indirectly restricted the use of the
word to the two latter conditions, for in those varieties known as Simple
or Cutaneous and Tendinous, the wound is generally broad and open, or,
at any rate, superficial, and can scarcely be strictly described as
'fistulous.' In the two latter, however, a true fistula exists. These,
however, have only one essential difference, and that consists simply in
the position of the lesion and the structures it has attacked. In the main
the symptoms will be the same, the disease in each case about equally
serious, and in each the same essentials of treatment will have to be
regarded.
In our opinion, therefore, a lengthy classification serves no useful end,
and we think matters will be simplified by considering quittor under
two headings only--namely, 'Simple or Cutaneous' and 'Sub-horny,' and
discussing the other varieties as simply complications of either of these
two.
1. SIMPLE OR CUTANEOUS QUITTOR.
_Definition_.--This condition is simply a sloughing of a portion of the
skin of the coronet, together with a portion of the immediately underlying
soft structures.
_Causes_.--This form of quittor has its origin more often than not in
contusions, punctures, or wounds of the region severe enough to cause death
of a small portion of the tissues. In this case the low vitality of the
parts does not allow of the dead portion being removed piecemeal by a
process of phagacytosis, as is usually the case with similar injuries
elsewhere. Instead, the tissues around, aided by a process of suppuration,
cast the offending portion off as a slough. It is the wound remaining after
the slough which we may really regard as a quittor. In this connection may
be considered as causes blows from falling shafts, self-inflicted treads,
or treads from other horses, overreach, etc. On the other hand, simple or
cutaneous quittor may occur without ascertainable cause. In this case we
can only explain its appearance, as we did that of simple coronitis (see p.
231), by attributing it to septic infection through a wound or a blow that
is able to inoculate the skin, yet which is insufficient to cause pain, or
in any other way attract the attendant's notice. Meanwhile, the spot of
infection thus started spreads, and the end result is an abscess in the
coronary region, again accompanied with necrosis and sloughing of more or
less skin and other tissue, which terminates by discharging its contents
and leaving behind a wound which again constitutes a cutaneous quittor.
Thus, as with simple coronitis, anything lowering the vitality of the
parts, and so favouring infection of the skin, may bring about a quittor.
Walking through much water in the winter months, through the dirt and mud
of our streets, through melting ice and snow, or through anything in the
nature of a chemical irritant, may be looked upon as a cause.
_Symptoms_.--Whether commencing from an ascertainable injury, or beginning
at first unnoticed, cutaneous quittor is characterized sooner or later by
the appearance of an inflammatory swelling, usually confined to the seat of
injury. Heat and tenderness are present, and the animal is lame.
Later the inflammatory swelling becomes more profuse, the animal is
fevered, and the symptoms of lameness increased. Poulticing is at this
stage perhaps resorted to. By its means the process of suppuration is
aided, and the swelling (at first tense and hard) either becomes gradually
softened, its contents discharged, and a simple abscess cavity left behind,
or the suppuration runs immediately round the necrosed structures, and
casts them off bodily as a slough. This latter condition is always
manifested, where the hair does not hide it, by the colour of the skin. At
first this is only red in colour--the angry red of an inflamed spot. As its
intention to slough away becomes evident, the red gradually gives way to a
gray, or even blue-black appearance, while from around it oozes a slight
discharge of pus, yellow in colour and non-offensive, or blood-stained and
dark in appearance, and foetid to the smell.
Almost invariably these symptoms are added to by a more or less diffuse and
oedematous swelling of the lower portion of the limb, extending in some
cases to as high as the fetlock or the upper third of the cannon.
With the casting off of the slough the phenomena of inflammation to a great
extent subside, the pain ceases, and the case under ordinary conditions
commences to mend.
_Pathological Anatomy_.--In its early stages the condition of simple or
cutaneous quittor is really a condition of acute coronitis (see p. 229),
and consists in an inflammation of the subcutaneous tissue, and the more
superficial portions of the coronary cushion. The tissues implicated are
destroyed outright, become infiltrated with the inflammatory exudate and
escaped blood, and act as a source of irritation to the still living
tissues around. Under the irritation the latter, as we have said before,
cast the necrosed portion away by a process of sloughing.
Always, however, it is found that the portion to be sloughed off, while
easily separated from the tissues adjacent to its sides, is closely
connected on its lowermost or deeper face with the structures below, and
cannot be torn away without haemorrhage and the causing of acute pain.
_Prognosis_.--With wounds about the feet our forecast should always be
guarded. Even with this, the most simple form of quittor, no decided
opinion should be given until the progress of the case warrants one in
reasonably assuming that complications are absent. Once this point is
decided, a favourable prognosis may be given.
_Complications_.--With cutaneous quittor various complications may arise,
according to the extent of the invasion of the septic matter. Necrosis of
tendon, of ligament, or of cartilage, caries of the bone, or a condition of
synovitis and arthritis may be met with. As these complications are equally
common to sub-horny quittor, we shall reserve their description until
dealing with that condition. _Treatment (Preventive)_.--Immediately after
the infliction of an injury in this position, more especially if it is such
as to lead one to judge that necrosis will follow to any large extent, the
patient should be rested. Ill effects may then be probably warded off by
having the foot immersed in a cold antiseptic solution, and afterwards
bound with an antiseptic pad and bandage.
_Curative_.--When the condition has gone undiscovered until commencing
necrosis and suppuration are plainly discernible, then the wisest course we
can follow is to do all we can to hasten removal of the necrosed portion.
This is best done by promoting the suppurative process by means of warmth
or stimulant applications.
To this end hot poultices, or, better still, hot baths, should be resorted
to. Under their influence a greater supply of blood is directed to the
still healthy tissues enabling them to actively continue the inflammatory
processes necessary to the detaching of the portion necrosed, while, at
the same time, the pus organisms, stimulated by the heat, are stirred into
greater activity, and the readier accomplish their purpose of destroying
the adhesion still existing between the necrotic portion and the
surrounding living tissues.
When prolonged poulticing or bathing cannot be practised, then the swelling
should be stimulated with a sharp cantharides blister, repeated, if the
case demands it, at intervals of a few days.
Should the swelling show distinct signs of pointing, and an abscess is
plainly the condition to be dealt with, its contents should be liberated by
a free use of the knife. In this connection it is important to insist on
the fact that the opening should be made large enough. One bold incision
from the uppermost limit of the swelling down to the coronary margin of the
wall is usually sufficient.
Even when pointing is not very evident, and suppuration is plainly more or
less diffuse, benefit may still be derived from the use of the knife. In
this case a deep scarification of the part is indicated. Three, four, or
more vertical incisions are made in the swelling, and from them obtained a
flow of blood mingled with a small quantity of pus from several different
centres. By this means sloughing of the diseased portion is quickly
obtained, and nothing but an ordinary open wound left for treatment. It
should be mentioned, however, that when sloughing can be in any way induced
to take place naturally it is better to allow this to take place. Even when
the necrosed portion is freely movable, and only adherent by its base, it
should not be forcibly removed, but left to the slower but more effectual
action of the tissue reactions. If torn forcibly away, we in all
probability leave in the bottom of the wound remnants of the dead tissue,
which, being small and consequently less productive of inflammatory
phenomena, are not so readily sloughed as the larger portion. These remain
as centres of infection, and prolong the case.
Once a suitable slough has occurred, the after-treatment is simple. It
consists in dressing the wound with reliable antiseptics, and maintaining
the parts in a healthy condition until Nature completes the cure by
repairing the breach. Solutions of carbolic acid, of perchloride of
mercury, of zinc chloride, or of moderately strong solutions of copper
sulphate, are all of them useful (see also treatment of coronitis on p.
236).
It is sometimes found that even with careful attention the wound left
by the removal of the slough shows a marked disinclination to heal. The
greater portion of the cavity becomes filled with granulation tissue, and
the epidermis gradually closes round until all is covered except a spot of
perhaps the size of half a crown or a crown piece. Here the regenerative
process stops, and the wound obstinately refuses to effectually close.
In such cases we have derived excellent results with the actual cautery.
The animal is cast, the foot firmly secured by fastening it upon the cannon
of another limb, and the animal chloroformed. A practical point to be
remembered in this connection is that all necessary fixing of the limb is
easier performed if the chloroform is administered first. With the patient
thus secured we first of all ascertain by means of the probe whether or no
the non-healing of the wound is due to the presence of a fistula. Decided
in the negative, we take an ordinary flat firing-iron, and with it cut away
a portion of the skin immediately around the still open wound, carrying
our incisions deep enough to 'scoop' out a large portion of the new
inflammatory tissue beneath. With the loss of pressure from beneath,
occasioned by the removal of so much of the cicatricial tissue, the
epidermis the more readily closes over the wound. To a large extent also
this new growth of epidermis is helped by the renewal of the inflammatory
phenomena brought into being with the cauterization.
2. SUB-HORNY QUITTOR.
_Definition_.--A fistulous wound of the foot in which the lower and blind
end of the fistula is situated below the level of the coronary margin of
the wall.
_Causes_.--These, again, will be practically the same as those mentioned
in the cause of cutaneous quittor--namely, bruises, punctures, wounds--in
fact, any injury upon the coronet severe enough to cause death of tissue
and a suppurating wound. We may thus expect sub-horny quittor to follow
upon treads, overreach, accidental injuries with the stable-fork, and kicks
from other animals.
Sub-horny quittor may also arise without original injury at all to the
coronet. Either from a violent blow upon the hoof, or from the animal
himself kicking violently against a wall, death of a portion of the
sensitive structures takes place within the hoof, suppuration ensues, and
the formation of quittor commences. With the escape of the pus at the
coronet the quittor is fully formed.
Any other diseased condition of the foot in which suppuration is present
may in like manner terminate in quittor. In complicated sand-crack,
suppurating corn, or in ordinary pricked foot quittor may be a sequel. In
these conditions the pus formation either goes unnoticed or is neglected,
and after seriously invading the sensitive structures within the hoof,
breaks out at the coronet. Again, too, as with the simpler form of quittor,
and as with coronitis, we may always regard as a predisposing cause the
action of excessive cold in promoting septic infection of the wound when
occurring at the coronet.
_Symptoms and Diagnosis_.--Where the fistulous wound has had its
starting-point in an injury to the coronet diagnosis is, of course, easy.
The history of the case explains it. Nothing in this instance remains but
to probe the opening, and ascertain its direction, depth, and extent.
An animal with the wound thus open at the coronet, and freely discharging
its contents, may, if no serious complications exist, walk tolerably sound.
It is only when put to the trot that symptoms of lameness are apparent.
It may so happen, however, that we first see the case when the symptoms are
wholly those arising from a painful suppuration within the horny box.
This occurs when the original injury has taken place at a more dependent
position than the coronet. Either from violent blows upon the hoof,
puncture from below, from corn or from sand-crack, or any other causes we
have enumerated, suppuration is occurring deeply within the hoof, with as
yet no opening upon the coronet.
Even when an opening has already occurred on the coronet, the same
condition of sub-horny suppuration may be met with in cases when the
opening of the fistula has by some means or other become occluded.
Granulation tissue, for instance, may have temporarily closed the mouth of
the fistula. The pus, instead of continuing its discharge thereat, is made
to burrow in other directions.
In either of these cases pain is excessive, the animal walks on three legs,
the foot is painful to percussion, and grave constitutional disturbance
is noticeable. The presence of pus is immediately suspected, and, in the
absence of any indication of an opening having existed at the coronet,
searched for at the sole. It may or may not be found. If found it is given
exit, and the case ends as one of ordinary pricked foot, of suppurating
corn, or some other condition equally simple when compared with quittor.
In those cases where the pus is not discovered at the sole, one adopts the
expectant treatment of poulticing. This, if pus is present, is followed
by a painful swelling of the coronet. At one point there forms a hot and
tender enlargement, with the hairs on it standing straight up from the
skin, which latter is seen below red and inflamed in appearance.
Later, the abscess--for abscess it is--discharges its contents, the opening
is explored, and we find that in extent it is not confined to the coronary
region, but that it is deep enough to constitute a true sub-horny quittor.
This discharge of the abscess contents may take place at a well-defined
spot on the coronet, or it may ooze out at the junction of the wall
with the skin. In appearance the discharged pus varies. When the softer
structures only are attacked it is thick, and yellow or white in colour;
when bone is involved it is ichorous; and when attacking the horn itself
black or gray. It may or may not be extremely foetid, and often it is
mingled with blood.
When evidence of a previous opening upon the coronet is plain, then it is
not considered wise to attempt a paring of the sole. Instead, poulticing
is at once resorted to, to induce the discharge of the pus through its
original channel. Once this has occurred a fistulous wound remains, which
is open for treatment upon one or other of the lines we shall afterwards
indicate.
COMPLICATIONS--_(a) Necrosis of the Lateral Cartilage_.--This is the
so-called 'cartilaginous quittor' of other writers. In all probability it
is the condition generally understood when the word 'quittor' is used by
one practitioner to the other. Its tendency to keep the disease existing in
a chronic form renders it of grave importance, and for that reason we give
it first mention among the complications.
It may occur as a sequel either of cutaneous or of sub-horny quittor, and
may result either from actual wounding and infection of the cartilage, or
from an attack on it of septic matter originating elsewhere.
Unless there has been discovered a fistula, which on probing is seen to
lead direct to the position in which we know the cartilage to be, we
know of no precise means by which the existence of this condition may be
diagnosed. When free from other complications, the horse with his foot in
this state may travel fairly sound. This is so when the necrosis is situate
in the posterior half of the cartilage, in which case the irritation set up
by the disease is confined to the comparatively non-sensitive tissues of
the cartilage itself and the fibrous mass of the plantar cushion. When
attacking the anterior half of the cartilage, the close contiguity of the
joint renders the disease of a more serious nature. It is then that we have
acute pain, and with it extreme lameness, for in this position it is more
than likely that we have involved either the synovial membrane of the
articulation or the tops of the sensitive laminae. It will be remembered
that here the synovial membrane protrudes as a small sac between the
antero- and postero-lateral ligaments of the joint. More or less easily
then it is bound to come into intimate contact with the septic matter
attending the necrosis of the cartilage, and so share in the inflammatory
processes, afterwards communicating them to the interior of the
articulation.
With necrosis of the lateral cartilage is always swelling and thickening of
the skin and subcutaneous structures of the coronet. This is the greater
the longer the disease has been in existence. Upon the swelling is seen the
mouth of the fistula, or it may be the mouths of several, and from them all
a discharge of pus.
The mouth of each fistula is generally filled with a mulberry-like
granulation tissue, standing above the level of the skin, and bleeding
easily if touched. The exuding pus is thin and pale gray in appearance,
gritty to the touch, and generally free from pronounced smell. At other
times its colour is reddened with contained blood, and floating in it are
tiny particles of a pale-green substance, which when picked up and rubbed
between the fingers are seen to be small fragments of the diseased
cartilage.
Should the mouth of a fistula become occluded with the granulations filling
it, and the discharge prevented from escaping, it soon happens that we have
close to the fistula that has closed a tender fluctuating swelling. This
points and breaks, and pus is again discharged from another opening. In
this manner is accounted for the multiplicity of scars and fistulas seen on
the swelling of an old-standing quittor.
The continued, inflammation thus kept in existence has the effect of
rendering the skin and subcutaneous tissues in the neighbourhood greatly
thickened and indurated. This in time leads to a tumour-like enlargement,
and causes the structures of the coronet to greatly overhang the hoof. At
the same time the constant inflammation has made its stimulant effects
noted in a great increase in the growth of the horn of the wall.
Although more abundant, however, the quality of the horn is deteriorated.
The perioplic ring has become obliterated, and the varnish-like appearance
of the healthy wall destroyed. Cracks and fissures in its surface are
numerous, and sometimes deep enough to lead to exposure of the sensitive
structures beneath, complicating the quittor with a sand-crack of a
peculiarly objectionable type.
_Pathological Anatomy of the Diseased Cartilage_.--The bulk of observers
appear to agree in the statement that in quittor the necrotic cartilage is
pea-green in colour, and recognise it by that characteristic. In size the
necrotic portion thus recognisable varies from the tiniest speck to a
portion the size of a horse-bean. Commonly, however, it is about as large
only as a pea. It is seen to be more or less detached from the rest of
the cartilage, to which it is adherent by one of its extremities only. In
general appearance we can best liken it to the split half of a green pea,
whilst others have compared it with the green sprouting of a seed. The
portions of cartilage nearest the necrotic piece are also slightly green in
colour, thus indicating that here also the diseased process has commenced.
This peculiar change of colour in the affected cartilage is of great
importance to the surgeon. It enables him when operating to distinguish
with some degree of certainty those portions of the cartilage which are
healthy and those which are not.
_(b) Necrosis of Tendon and of Ligament_.--This complication of quittor
is, as we have said before, treated by other writers as a distinct form of
the disease, and described by them under the heading of Tendinous Quittor.
This simply means, of course, that the diseased process has extended to
either of the flexor tendons, to the tendon of the extensor pedis, or,
perhaps, to the ligaments of the pedal articulation.
Of the flexor tendons, the perforans is the one commonly attacked, by
reason, of course, of its more superficial position. At times, however,
especially when its aponeurotic expansion is diseased, the necrosis of the
perforans spreads until the aponeurosis is eaten through and the phalangeal
sheath penetrated. Septic materials gain entrance thereto, and commence to
multiply. In this way the flexor perforatus is invaded, and comes to share
in the diseased process.
The extensor pedis is usually attacked by extension of the disease from a
necrotic cartilage, or results from the infliction of a severe tread in a
hind-foot. In this case the diseased structure has nothing between it and
the articulation, the synovial membrane in one position actually lining its
inner face. The result is that a condition of synovitis is easily set up,
and the case aggravated by that and by arthritis.
With the flexor tendons attacked pain is always very great, and lameness is
excessive. This, however, is not sufficiently characteristic to enable us
to determine the precise seat of the necrotic changes. Later, however, a
tender but hard enlargement made its appearance in the hollow of the heel,
which enlargement, later still, became soft and fluctuating. At this stage
there is also considerable swelling along the whole course of the tendons,
as high up as the knee or the hock. The foot is carried forward with all
the phalangeal articulations flexed, and in many cases the limb is unable
to take weight at all. Manipulated after the manner of examining the
tendons for sprain, this swelling is found to be extremely painful. The
animal flinches from the hand, and shows every sign of acute suffering.
This condition may, in fact, be mistaken for sprain, and is only to be
distinguished from it by carefully noting the history of the case--first,
the appearance of the swelling in the hollow of the heel, and, secondly,
the _after_-swelling of the upper portions of the tendons.
The formation of the abscess, the after-discharge of its contents, and the
final establishing of a fistula, are processes greatly prolonged in this
form of quittor. It will readily be understood why this should be so when
one remembers the depth at which the suppurative process is going on, the
thickness of the metacarpo-phalangeal sheath, and the resistant nature of
the material of which this latter is made, and which must be penetrated
before the condition becomes observable.
After the opening of the abscess, which usually takes place in the hollow
of the heel, there is left the fistulous wound which obstinately refuses to
heal. Or it may be, again, that there are several of these fistulas, each
opening in the heel, and the mouth of each marked by a small, ulcer-like
projection. The discharge continually oozing from these keeps the heel
constantly wet with a thick purulent discharge, which is nearly always
blood-stained, and very often foetid.
This constitutes what is known as tendinous quittor in its worst form,
for more often than not there is associated with it inflammation of
the navicular bursa, caries of the bones, or arthritis of the pedal
articulation.
With the extensor pedis attacked matters are not quite so grave, in spite
of the fact that the articulation is closely situated thereto, for in this
case the more superficial position of the diseased structure allows both
of readier exit of the discharges and of easier removal of the necrosed
portion and after-treatment of the wound.
_(c) Caries of the Bones_.--Portions of the os pedis, more especially of
its wings, and therefore usually occurring in conjunction with necrosed
cartilage, become carious in quittor. In many cases it is impossible to say
with certainty when this has occurred. In a few instances, however, the
exuding discharge gives evidence of what has happened. It is thin, but
extremely offensive, with the characteristic odour of decayed bone or
tooth, and with a feel that is gritty with contained particles of broken-up
bone. If, with a discharge of this nature present, the probe also conveys
to the fingers the sensation that bone is reached, then diagnosis may be
sure.
_(d) Ossification of the Cartilage_.--This may take place in part or in
whole. It, of course, constitutes Side-bone, a fuller description of which
will be found in a later portion of this chapter.
_(e) Penetration of the Articulation_.--This may occur either as a result
of the suppurative changes or as an accident in excision of the diseased
cartilage. Unless it is followed by a severe purulent arthritis, it is not
so grave a complication as at first sight it would appear.
_(f) Synovitis and Arthritis (Purulent)_.--Should this complication arise,
the case is a most serious one. Beyond here mentioning the fact that it may
occur, we shall not dwell on it. Fuller consideration is given to it in
Chapter XII.
_Treatment_.--The various treatments adopted for the cure of sub-horny
quittor offer the veterinary surgeon a large number to select from. We
will describe them in the order in which they are, perhaps, most commonly
practised.
_Poultices and Hot Baths_.--As in cutaneous quittor, and as in coronitis,
when the pus formation is only suspected, and has not yet broken out at the
coronet or elsewhere, then the first indication in treatment is the use
of warm poultices or of hot baths. Their application is in most cases
productive of pointing at the coronet.
Directly this appears it is a wise plan to thin the wall down with the rasp
immediately below the swelling. To some extent it relieves the pressure of
the inflammatory products within, and at the same time paves the way for
operative measures which may be necessary later on.
With the breaking of the abscess and the discharging of its contents, we
may in some measure ascertain the condition we have to deal with. The probe
is used, and the abscess cavity explored. The size of the wound, its depth
below the upper margin of the wall, the structures involved, and other
information, may be thus obtained.
At first, however, the nature of the wound, and the character of the
discharges, must largely guide us as to the treatment we adopt. In many
cases, even where the abscess cavity is far below the upper margin of the
wall, and is presumably in an unfit position to drain and heal, a a regular
application of an astringent and antiseptic dressing is sufficient to bring
about resolution. If, however, the discharge from the wound continues to be
liquid, and the wound itself at one spot refuses to heal, it may be judged
that a portion of necrotic tissue is situated under the wall, and affecting
the laminae, the cartilage, or ligament, as the case may be. If this is so,
then operative measures must be determined on (see Removal of the Wall, p.
349).
_Blisters_.--Instead of the poultice and hot baths, the pointing of the
abscess and the casting off of the slough may be brought about by the
application of a sharp cantharides blister. We have, in fact, seen many
cases where this treatment was adopted prior to the formation of a fistula,
and also in cases where one or more fistulous openings already existed,
where repeated blisters to the coronet have alone been sufficient to effect
a cure.
We are bound to admit, however, that the treatments of poulticing and
blistering are only expectant--we might almost say empirical. At any rate,
we admit to ourselves that what we have advised and carried out is not in
itself curative, but only a means of assisting Nature to satisfactorily
work her own ends. Empirical or not, however, we believe that in every
case of quittor it is wise in practice to at first adopt some such simple
measure, for in nearly every instance where operative measures are
practised, the patient must be laid aside for at least several weeks,
whereas in this way he may be kept at work and a cure effected at the same
time.
_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.
_The Potential Cautery_.--This is employed in the treatment of sub-horny
quittor, either in the solid form (in sticks, in lumps, or in the powder),
or in the liquid form, when it is injected with a quittor syringe.
In the former method such drugs as perchloride of mercury in the lump, or
nitrate of silver, chloride of zinc, and caustic potash or soda in the
stick, are introduced into each of the sinuses present. This is done by
means of a director or a probe.
A better method, however, when the dressing lends itself to the purpose, is
to use it in the form of a powder, wrapped in the form of small cubes
in extremely thin paper, such, for instance, as is used for rolling
cigarettes. It is then conveniently inserted into each fistula. Introduced
in this more finely divided form the drug is, perhaps, a little more active
in bringing about the desired result.
This method of 'plugging,' although practised by many, we cannot recommend
in preference to the use of the hot iron or of liquid injections. Our
reasons are these: the action of the drug is a protracted one. Almost
immediately after its introduction into the fistula there is formed about
it an almost impermeable layer of a metallic albuminate, which effectively
prevents further rapid action of the caustic. In addition to thus
preventing further action of the dressing, this combination of the tissue
albumin with the metal of the salt, together with much necrotic tissue that
it has caused, is extremely hard to remove from the healthy tissues. This
we explain by pointing out that the action of the caustic, prolonged as
it is, sets up a tissue reaction which partakes largely of the type of a
chronic rather than an acute inflammation. With a chronic inflammation
there is sooner a tendency to the production of fibrous tissue (and thus
the firmer attachment of the necrosed portions) rather than an active
phagocytosis and the casting-off of a slough. Again, careful though we may
be with the probe, it is extremely difficult to be certain that we have
discovered the whole extent of any fistula. An equal difficulty, therefore,
exists in being certain that we have placed the caustic in the position
in which it is most wanted--namely, at the furthermost end of the fistula
where the necrotic tissue is to be found.
When a caustic is used at all, it is far better to employ it in the liquid
form, when either of the drugs we have just mentioned may again be used. In
the first place, the liquid is far more likely to be brought into contact
with the diseased structures than is the solid salt. Also, its action may
be regulated by altering the strength of the solution, and the liability to
form impermeable albuminates thus diminished.
Probably the best solution for use in this way is the old-fashioned
Villate's solution (see p. 199).
This liquid should be injected at least every day, and, in a bad case,
even two or three times daily. Practical hints to be borne in mind when
attempting to cure quittor by means of injections are these:
If the fistulas are numerous, the fluid should be injected into their
various orifices.
In order to force the fluid to the bottom of each diseased track, it is
necessary, when injecting one opening, to firmly close all others.
Several injections should be made at each time of injection. In other
words, we must not be content with just forcing fluid in. It must be forced
in, and again forced out by a further syringeful. The fistulous tracks
must, in fact, be washed in the liquid.
The effect of the injection during the first eight or ten days is to render
suppuration more abundant and whiter. After two weeks of the treatment
sloughing of the inside of the sinuses occurs, and healing of the wound
commences. Signs that this is occurring are--slight haemorrhage at the end
of each injection, and a gradually increasing difficulty in forcing in the
fluid.
_The Making of Counter-openings to the Fistulas_.--Although Villate's
solution or any other caustic used in the manner we have described
often effects a cure, many practitioners insist on the fact that a
counter-opening to the fistula must also be made.
The probe is used and the direction and depth of the fistula ascertained.
Through the wall is then made an opening at exactly opposite the lowest
point found by the probe, or through the sole if the probe should there
lead us. This opening is best made with a sharp-pointed iron, and may
afterwards be kept large enough by an occasional trimming with the knife.
Many of the older authors, and with them writers of the present day,
declare that unless this is done the ordinary injection is likely to fail
in a great many instances where it would otherwise have been successful.
Where a counter-opening is thus made it is found that it very readily
closes with granulation tissue, and the purpose for which it was made
defeated. This may be avoided by the use of a seton. In preference to the
seton, however, we ourselves would advise that the opening be kept free by
the occasional use of a sharp-edged director or a fine scalpel.
An interesting modification of the practice of making a counter-opening is
that related by Veterinary-Captain S.M. Smith.[A] In point of severity it
runs a middle course between the making of a simple counter-opening and
the removal of a wedge-shaped portion of the coronary band and the wall, a
method which we shall later describe.
[Footnote A: _Veterinary Record_, vol ii., p. 157.]
To perform this operation, the animal is cast and chloroformed. The foot is
fixed and the parts thoroughly cleansed. The horn of the wall is then sawed
through in a direct line from the coronary margin to the solar edge, the
saw-line running exactly over the seat of the sinus.
A strong scalpel is now introduced at the coronary opening, with its
cutting-edge outwards, and is gradually passed down the opening made by the
saw. In this way the sinus is completely destroyed, and from end to end
converted into an open wound. The parts are then washed in a perchloride of
mercury solution, covered with a mixture of powdered iodoform and boracic
acid, over which a pledget of carbolized tow is placed, and then a bandage
over the whole. This dressing should be left on three or four days, after
which the injury should be treated as an ordinary wound. In conclusion,
the author says: 'I can safely recommend this line of treatment to any
practitioner having an obstinate case under treatment.'
_Removal of the Wall and Excision of the Necrotic Tissue_.--This we
may term the radical operation for sub-horny quittor, for it is often
productive of a successful issue when all other means have failed. No
matter in what position the sinus is, whether at the extreme anterior
portion of the coronet, or whether in the region of the heels, it is to be
thoroughly opened up. To do this, the fistula is carefully explored with
the probe and a knowledge of its exact dimensions arrived at. This is
carefully noted, and the horn of the wall for some little distance around
it then rasped down quite thin. Immediately over the sinus, and for a short
distance on either side of it, the horn is stripped away to the sensitive
structures. The cavity of the fistula is then opened up with a scalpel, and
every particle of diseased tissue removed with this instrument and a pair
of forceps. After-dressing consists simply in the application of suitable
antiseptics.
_When the Complication of Necrosed Tendon or Ligament exists_.--We may take
it as an axiom that wherever this exists, whether it is in the extensor
pedis, in the lateral ligaments of the joint, or in portions of the
flexors, all diseased structures should, where possible, be removed. This
is done either with a scalpel or with a curette.
When septic matter has gained the sheath of the perforans, and the
formation of pus therein is indicated by inflammatory swellings in the
hollow of the heel, it is sometimes advisable to lay the sheath open for 1
to 2 inches along the course of the tendons. This, if a fistula is present,
may be best done with a blunt-pointed bistoury, or with a cannulated
director and a scalpel. With the pus thus given exit, and an antiseptic
dressing regularly applied, the case sometimes ends in rapid resolution.
More often than not, however, it is found that the pus has been liberated
too late, and that it has gravitated in the sheath to the extent of
affecting the plantar aponeurosis. Or it may be, of course, that it was in
the plantar aponeurosis the disease commenced. Whichever may have been the
case, we have in the hollow of the heel one or more fistulous openings, or
an opening we have made ourselves, leading down to a necrosed portion of
the terminal expansion of the perforans.
In such cases we ourselves have derived benefit from a regular flushing
of the sinuses with a 1 in 2,000 solution of perchloride of mercury,
introduced by means of a glass syringe, followed later by flushing in the
same manner with a 1 in 40 solution of carbolic acid, the hollow of the
heel meanwhile being kept clean with an antiseptic pad and bandage, or by
liberal applications of an antiseptic powder.
The septic materials are in this way destroyed, and the wound heals without
further complication. We must admit, however, that the cure of the lesion
is generally at the expense of slight lameness, due, in all probability,
to inflammatory tissue adhesions between the flexor perforans and the
perforatus, and to a partial destruction of the synovial membrane of the
sheath.
If, in spite of the antiseptic irrigations, the fistula persists, then
nothing remains but to resort to excision of the aponeurosis, as described
on p. 222.
_When Necrosis of the Lateral Cartilage is present_.--In this case we may
at first try the ordinary treatments of poulticing; and blistering, of
antiseptic caustic injections, and of plugging. In some cases a cure is
effected. Should these fail, however, and we intend to see the finish of
our case, then operative measures must be determined on. This means cutting
down upon the diseased cartilage, and either removing the necrosed portion,
or excising the cartilage in its entirety.
The latter method is seldom practised in this country. As it is the most
radical of the two, however, we shall describe it here first.
_Extirpation of the Lateral Cartilage_.--The operation of extirpating the
lateral cartilage is by no means a new one, being introduced, according to
Zundel, by the senior Lafosse in 1754. It consisted in removing a portion
of the wall by grooving and stripping it, and of excising the exposed
cartilage by means of a sage-knife.
As to what portion of, and how much of the horn of, the quarter should
first be removed, and as to what particular direction each groove should
take, opinion among the older writers varied considerably. This we know
now is not an important matter, and it is sufficient to say that the first
preliminary is a thinning down of the horn of the quarter with the rasp
over the position occupied by the cartilage. At the present time there are
two or three modifications of the operation as originally introduced.
In all, however, the preliminary steps are the same. We shall therefore
describe them collectively, as applying correctly to either of the three
methods of operating we are about to show.
_Preparation of the Subject and Preliminary Steps in the Operation_.--On
the day previous to the operation the horn of the wall immediately over the
cartilage must be so thinned with a rasp as to yield readily to pressure
of the thumb in any position. It should be so thin as to only just avoid
wounding the sensitive structures below.
The whole of the foot must then be thoroughly cleansed, and rendered as
nearly aseptic as possible. The use of warm water, soap, and a stiff brush
is the readiest means of removing the surface dirt. Afterwards the foot
should be soaked for some time in a reliable antiseptic solution, a 1 in
1,000 solution of perchloride of mercury being the most suitable. When
removed from the solution the foot must be packed round with wool or
tow impregnated with corrosive sublimate, and then bandaged, the whole
afterwards wrapped in a thick cloth, or protected with a boot.
On the following day the animal is brought out and cast, and the foot
desired to be operated on firmly secured, after the manner described on p.
81. The bandages and sublimate pads are then removed, and the skin of
the coronet over the seat of operation shaved of hair. An Esmarch rubber
bandage is next run up the limb, and the tourniquet applied, thus rendering
the operation a nearly bloodless one.
This done, the animal is chloroformed, and an antiseptic douche played over
the foot.
So far, the steps in the operation are common to all methods. There are
now, however, three slightly differing modes of extirpating the cartilage,
which modes vary simply according to the structures severed by the knife.
_First Method_.--This is the oldest method of the three, and consists in
making (1) a horizontal incision through the sensitive laminae along the
lower border of the cartilage, and (2) a vertical incision through the skin
of the coronet, the coronary cushion, and a portion of the sensitive laminae
(see Fig. 139).
The flaps (Fig. 139, _a, a_) are now held back by tenaculae, and the whole
of the cartilage, or only the necrosed portion, carefully excised by means
of right- and left-handed sage-knives. Fistulous openings in either of the
flaps _a, a_ must now be carefully curetted and dressed, and the flaps
allowed to fall into position. They are then sutured with carbolized gut,
and the wound finally dressed as to be described later (p. 357).
[Illustration: FIG. 139.--EXCISION OF THE LATERAL CARTILAGE (OLD METHOD).
The wall covering the lateral cartilage first thinned and stripped off; the
two flaps (_a, a_) of skin and the coronary cushion made by the vertical
incision turned back. _a_, The operation flaps; _b_, the exposed cartilage;
_c_, the sensitive laminae; _d_, the coronary cushion.]
_Second Method (after Holler and Frick_[A]).--These operators deem it wise
to leave untouched the skin of the coronet and the coronary cushion. They
therefore make their first incision along the lower border of the coronary
cushion (see Fig. 140), afterwards exposing the lower half of the cartilage
by removing a half-moon-shaped portion of the thinned horn and underlying
sensitive laminae (see Fig. 140, _b_).
[Footnote A: Two cases of quittor successfully treated by this method are
reported by R. Paine, M.R.C.V.S., in the _Journal of Comparative Pathology
and Therapeutics_, vol. xv., p. 81.]
[Illustration: FIG. 140.--EXCISION OF THE LATERAL CARTILAGE. (AFTER MOLLER
AND FRICK.) _a_, The thinned horny wall covering the coronary cushion; _b_,
the lateral cartilage exposed by stripping off the thinned wall; _c_, the
sensitive laminae.]
This done, the external face of the cartilage is separated from the skin
of the coronet. To do this a double sage-knife is run flatwise between the
coronary cushion and the cartilage, with the convex surface of the blade
towards the skin. The knife is then passed backwards and forwards until the
necessary separation is accomplished. During these movements of the knife
a finger of the unoccupied hand should follow the knife, and guard the
coronary cushion against injury.
Following this, the inner surface of the cartilage must be also separated
from the structures lying beneath it. To this end a sage-knife (right- or
left-handed, according as to whether the anterior or posterior portion of
the cartilage is to be first removed) is again passed into the incision.
With the cutting-edge of the knife forward, it is gradually reached round
and under the hindermost end of the cartilage, and theposterior half of
the cartilage separated from underlying structures, and at the same time
excised by one clean cut forwards. Using the second sage-knife in a similar
manner, the cutting-edge this time backwards, it is reached in front of the
cartilage, whose anterior half is then excised by a careful cut backwards.
Any small portions of cartilage remaining after this are sought for with
the finger, and carefully removed by means of a scalpel and a tenaculum.
The fistulous opening or openings in the skin of the coronet should now be
thoroughly curetted, and the whole of the wound dressed as to be described
later.
In removing the anterior half of the cartilage it is highly important to
remember the close contiguity to it of the synovial membrane of the
pedal articulation. This projects as a small sac between the antero- and
postero-lateral ligaments of the joint. Risks of injury to it may be
diminished by having the foot secured with a line, and pulled forward by an
assistant while the cut is being made.
_Third Method (after Bayer)_.--This operator recommends that, after
stripping a half-moon-shaped piece of horn from the seat of operation,
instead of raising the skin of the coronet and the attached coronary
cushion in two flaps (as Fig. 139, a, a), that the cartilage be exposed
by raising up one flap only (Fig. 141, a), consisting of a portion of
the sensitive laminae, the coronary cushion, and the skin and underlying
structures of the coronet.
With the horse cast and the preliminary steps over, the thinned horn of
the quarter is incised in a semicircular fashion, and the half-moon-shaped
piece thus separated from its surroundings stripped off. At about 1/4 inch
from the incision in the horn, a second incision of similar shape is made
through the sensitive structures, which incision is also carried up into
the skin and structures of the coronet. This incision severs, from bottom
to the top, (1) the sensitive laminae covering a portion of the pedal bone
and a portion of the lateral cartilage, (2) the coronary cushion, and (3)
the skin of the coronet and such structures as lie between it and the
cartilage.
[Illustration: FIG. 141.--EXCISION OF THE LATERAL CARTILAGE. (AFTER
BAYER.) The horny wall is stripped off over the seat of operation. _a_,
Semicircular flap of sensitive laminae, coronary cushion, and skin; _b_, the
lateral cartilage; _c_, the sensitive laminae; _d_, the coronary cushion.]
That this incision of the sensitive structures should be kept at 1/4 inch
from the one in the horn has a reason. It is that when this flap is again
placed into position (as later it will have to be) we have round its
circumference a rim of soft structures into which to place the sutures. And
in this connection it is well to advise the operator that the thinness of
the keratogenous membrane (the laminal portion of it) should warn him that
the portion of it to be turned up--namely, that forming the tip of the
flap--should be _scraped_ away quite close to the os pedis. Unless this is
done, there will not be a sufficient thickness left to afterwards bring
into position and suture.
The half-moon-shaped piece of tissue incised is now carefully dissected
away from the external face of the cartilage, until it may be turned up as
a flap (see Fig. 141, _a_), and held from off the cartilage by a tenaculum.
The exposed cartilage is now carefully removed by the aid of a sage-knife
and a stout pair of forceps, the same precaution of holding the foot well
forward being again taken in order to avoid wounding of the articular
capsule.
At this stage in the operation considerable care is required. The operator
must remember that close beneath him, and more particularly in front, is
the pedal articulation. It is better, therefore, to excise the cartilage
piecemeal, and to do it carefully, than to attempt, at the risk of injury
to the joint, to make the operation 'showy.'
During removal of the cartilage, the terminal branches of the digital
arteries are wounded, as also are the veins of the coronary plexus. Should
either of these stand out with extra prominence from the others, it should
be picked up with a pair of forceps, and ligatured with either carbolized
gut or silk.
Attention should then be given to the flap of skin and coronary cushion.
Wherever a sinus has existed in it, it is to be carefully scraped, and all
dead portions of tissue removed. This done, the flap is allowed to fall
into position, and is there carefully sutured, not only at the skin of the
coronet, but along the whole circumference of the incision.
_Dressing of the Wound and After-Treatment_.--The whole secret of the
success of this operation is in afterwards maintaining a strict asepsis
of the wound. Unless there is reasonable room for belief that this may be
done, the operation had far better not be advised, for if the wound is
afterwards suffered to get into a suppurating and dirty condition, the last
stage of the case may be worse than the first Synovitis and arthritis, with
certain anchylosis of the joint, and a probable loss of our patient, is
almost bound to follow.
We cannot, therefore, too strongly insist upon the advice that the whole of
the preliminary antisepticising of the foot that we have described, and the
after maintaining of asepsis that we are now about to relate, _must_ be
methodically and thoroughly carried out. It is of even _more_ importance
than little details in the operation itself.
In the first and second methods of operating, directly the actual operation
is over, the surface of the wound and both surfaces of the skin-flaps
should first be thoroughly douched with a 1 in 1,000 solution of
perchloride of mercury. Bayer prefers a 1 in 5 solution of iodoform in
ether.
Next, either iodoform or chinosol in the powder should be dusted over the
whole surface, including again both inner and outer faces of the reverted
skin-flaps. This done the flaps are allowed to fall into position and
sutured there with carbolized silk or gut.
Another liberal application of an antiseptic dressing follows this.
Iodoform, iodoform and boracic acid, or chinosol, is freely dusted over
the wound and for some distance around it. Bayer, however, again prefers a
dressing of the wound, and especially the moistening of the line of sutures
with the 1 in 5 solution of iodoform in ether.
Over the wound is then placed a protective layer of gauze, impregnated
either with boric acid, with a mercuric salt, or with iodoform.
Finally, numerous small and lightly-rolled balls of dry carbolized tow
are packed regularly over the whole of the operation wound, and the foot
bandaged.
Practical points to be remembered in this after-dressing are: (1) The
balls[A] of tow should be numerous enough to exercise pressure upon the
sutured flap when the foot is finally bandaged. (2) The bandage should
be run on from the coronet downwards, in order to insure pressure being
exerted in the exact position over the sutured flap. (3) Bandages should
be used in abundance, commencing always from the coronet, and carefully
applied so as to exert an even and uniform pressure. (4) The bandages
should be of clean, unused linen.
[Footnote A: Bayer recommends that the tow be rolled into cylindrical
tampons, each long enough to cross the wound. These are placed on the wound
in alternate horizontal and vertical layers, so that when rolled round by a
bandage they are pressed into an even and compact pad.]
Once the bandages are adjusted, the hobbles may be removed, and the
tourniquet loosened. Directly the tourniquet is removed there is a steady
oozing of blood through the bandages, no matter how many we have put on.
This should occasion no alarm, as experience has taught that the careful
attention to antiseptic measures observed throughout the operation has the
effect of maintaining the lowermost dressings, those next to the wound, in
a state of asepsis. The bandaged foot should now be wrapped in a piece of
thick clean cloth or placed in a boot.
If our antiseptic precautions have been thorough, the dressings and
bandages so adjusted may be allowed to remain without disturbance for from
eight to fourteen days. In this, however, the veterinary surgeon must be
largely guided by the symptoms of his patient. If, at the end of the
first three or four days, the animal maintains a vigorous appetite, if he
commences to place a little weight on the foot, and if the thermometer
gives no indication of a rise beyond the one or two degrees of ordinary
surgical fever, then the surgeon may know that things are proceeding
satisfactorily. Pawing movements with the foot, inability to place weight
upon it, loss of appetite, an increase in the number of respirations, and
a serious rise of temperature, denote the opposite state of affairs. The
wound is in all probability suppurating. The bandages and dressings should
therefore be removed, and the wound either redressed and bandaged, or
treated as an ordinary open wound.
Ordinarily, however, if the operation has been properly performed, healing
takes place by first intention, and the wound when the bandages are removed
at the end of the first or second week appears clean and _dry_.
Having assured ourselves that such is the case, we dress the foot in
exactly the same manner as before, save that so many bandages are not put
on. A similar dressing is repeated weekly until such time as the wound
shows sufficient growth of horn--quite a thin pellicle--to act as a
protective. It may then be left undressed, except for some simple hoof
dressing and a bandage.
Complete healing of the wound takes from about four to eight weeks, at the
end of which time the animal can be again gradually put into work. The
labour, however, should be light, and quite three or four months should be
allowed to elapse before any attempt is made to put him to heavy work.
Should the second method of operating have been the one adopted, then there
is one slight difference in the after-dressing that needs attention calling
to it. In this case we have more or less of a _hidden_ cavity left to deal
with rather than the broad and _open_ wound left in either of the other
methods. This cavity, left by the extirpation of the cartilage, must be
thoroughly dressed with iodoform or chinosol, or with Bayer's iodoform
in ether. The packing with carbolized tow and the bandaging may then be
proceeded with as before.
In conclusion, we may say that the operation is one of some delicacy, and
needs a good surgeon for its successful performance. Furthermore, no one of
the antiseptic precautions we have advised can be omitted. It is, perhaps,
these two considerations (and in justice to the English surgeon we should
say most probably the latter of them) that have prevented this operation
from being generally adopted.
That it is successful there is no gainsaying. Professor Bayer, of the
Vienna School, with whose name is associated the last of the three methods
of operating we have described, is enthusiastic in praise of the operation,
and says: 'The favourable results that I have got by this operation have
caused me wholly to abandon the medicinal treatment, and to prefer in all
cases the surgical operation as being the best means to the end.'
_Partial Excision of the Lateral Cartilage_.--Discarding the somewhat
elaborate methods we have just described, there are English operators who
removed the necrosed portion only of the cartilage, and do so in what
appears at first sight a comparatively rough-and-ready manner.
The apparent roughness is that they do not concern themselves with
conserving the coronary cushion, and hesitate but little in cutting
portions of it bodily away. One would imagine that in this case the quarter
of the side operated on would be always more or less bare of horn. Such,
however, is not the case.
To perform this operation the animal is again cast and chloroformed. Some
operators, however, use the stocks and dispense with the anaesthetic. The
foot is first well cleaned with soap and water and a stiff brush, and the
hair of the coronet over the seat of operation shaved. Again, too, the horn
of the affected quarter is rasped until it yields easily to pressure of the
thumb, and the whole of the foot washed in an antiseptic solution.
A probe is now inserted into the opening at the coronet, and the direction
of the fistula noted, after which the foot is firmly secured, and an
Esmarch bandage and tourniquet applied to the limb.
This done, a triangular or wedge-shaped portion of skin, coronary cushion,
and thinned horn is removed with a strong sage-knife or scalpel.
The base of the wedge-shaped portion removed contains the opening of the
fistula, and the apex of the wedge should reach to the bottom of the sinus
(see Fig. 142).
After the horn is removed and the fistula followed up, it is sometimes
found that what we at first thought was its end, it may now be continued in
an altogether different direction.
It is again followed up with the probe, and the horn and sensitive
structures excised until we are quite certain we have reached its furthest
extent.
Attention should next be paid to the cartilage. Wherever spots of necrosis
are found, as indicated by the pea-green colour of the affected parts, they
must be _carefully_ excised. Care should be taken in so doing to carry the
line of excision some little distance around the visibly affected parts.
This is done that we may be quite certain nothing at all remains calculated
to give rise to further trouble.
It goes without saying that, in addition to the necrosed cartilage, all
other diseased and necrotic tissues should also be removed. The os pedis is
occasionally found necrotic just where the cartilage joins it, or it may be
that a small portion of the sensitive laminae, by reason of its _liver-red_
or even gray coloration, gives evidence of death of the part.
The former must be well curetted, and the latter cleaned carefully with a
scalpel and forceps.
[Illustration: FIG. 142.--PARTIAL EXCISION OF THE LATERAL CARTILAGE BY
REMOVING A PORTION OF THE CORONARY CUSHION. The dotted lines show the
outline of the wedge-shaped portion of structures to be removed, including
skin, coronary cushion, horn, and sensitive laminae. _a_, The opening of the
fistula.]
The operation finished, the foot is again douched in an antiseptic
solution, the wound mopped dry with carbolized tow, dressed with either of
the dressings described on page 358, and finally bandaged. The dressing
should be changed every three days only, unless in the meanwhile pawing
movements and other symptoms of distress indicate their removal.
The length of coronary cushion removed in this operation is from 1/4 to 1/2
inch (we ourselves, however, have seen it more), and yet its loss seems to
occasion no serious after-trouble beyond a slight deformity of the parts
beneath. The sensitive structures become sufficiently covered with horn,
and the animal in nearly every case is returned to work, while in a great
many instances he may also trot perfectly sound.
Simple though the operation may appear, and apparently rough in its method,
it is nevertheless successful in effecting a cure in cases where blisters,
plugging, injections, and other means have failed.
Mr. W. Dacre, M.R.C.V.S.,[A] after reading an article on the operation
before the members of the Lancashire Veterinary Medical Association, says:
'My observations have not been based on a single case, and having had nine
of them, and all of them successful, I felt it to be my duty to bring this
subject before the Society.'
[Footnote A: _Veterinary Record_, vol. v., p. 407.]
Mr. T.W. Thompson, M.R.C.V.S.,[A] says: 'In a great number of cases I have
removed a 1/2 inch of the coronary band.... I have performed the operation
a great number of times, and have never seen a foot that has been damaged
by it.'
[Footnote A: _Ibid_.]
Professor Macqueen[A] says: 'I do not spare the coronary band or sensitive
laminae when I find those parts diseased. I do not unnecessarily damage
those structures. At the same time, I am confident that excision of a piece
of the coronary band or removal of a few sensitive laminae has not the
untoward consequences so much dreaded in former days.'
[Footnote A: _Ibid_., p. 714.]
Mr. John Davidson, M.E.C.V.S.,[A] says: 'The treatment described, if
carefully carried out and details attended to, will be found a success in
dealing with the majority of cases of quittor. If I may be permitted to say
so, without being considered boastful, I have yet to see the first case
that has resisted the treatment.'
[Footnote A: _Ibid_., vol. xiv., p. 769.]
Should our case of quittor be complicated by caries of the bone, this must,
where possible, be scraped or curetted until the whole of the diseased
portion is removed, and a healthy surface is left. After-dressing must then
be carried out as in other cases.
The treatment of ossified cartilage will be found under treatment of
side-bones, and the methods of dealing with penetrated articulation and
purulent arthritis are treated of in Chapter XII.
_Surgical Shoeing in Quittor_.--In the case of simple or cutaneous quittor,
no alteration in the shoeing is necessary.
When the condition becomes sub-horny, however, and particularly when it is
situated in the region of the quarters, ease is afforded to the diseased
parts by removing the bearing of the shoe in that position.
Should there be no dependent opening at the sole, then the best shoe for
the purpose is an ordinary bar shoe (Fig. 68), with the bearing eased under
the affected quarter.
If, however, there is a dependent orifice, or one is expected, then it will
be necessary either to leave the animal unshod or to provide him with
a shoe that admits of dressing the lesion. In the latter case the most
suitable shoe will be found to be either a three-quarter shoe (Fig. 102)
or a three-quarter bar shoe (Fig. 103). Many operators, however, keep the
animal unshod. We must say ourselves that we consider a shoe useful after
either of the operations for removal of the cartilage, if only to assist in
maintaining the bandages and dressings in position.
In this case a very useful shoe will be the three-quarter bar shoe. With a
little manipulation the bandages are easily run under the bar portion of
the shoe, and a few of their turns every now and again wrapped round the
bar in order to keep the whole firmly in position.
In connection with tendinous quittor, when septic matter has gained the
sheath of the flexor tendons, there is, for a long time after healing of
the fistula, a marked tendency for the animal to go on his toe. To a large
extent we judge this to be due to slight adhesions between the two tendons
brought about by the growth of inflammatory fibrous tissue. In such cases
benefit is sometimes derived from the application of a shoe with an
extended toe-piece (see Figs. 84 and 108).
C. OSSIFICATION OF THE LATERAL CARTILAGES, OR SIDE-BONES.
_Definition_.--An abnormal condition of the lateral cartilages, in which
the substance of the cartilage becomes gradually removed and bone formed in
its place.
[Illustration: FIG. 143.--OSSIFIED LATERAL CARTILAGES (SIDE-BONES).]
_Symptoms and Diagnosis_.--Side-bones are nearly always met with in heavy
draught animals, and are rarely seen in the feet of nags. They are,
moreover, nearly always confined to the fore-feet. In the ordinary way
little need be said concerning their characteristics, and the way in which
they may be detected. Neither need any concern be ordinarily manifested
with regard to the effect they may have on the animal's gait and future
usefulness. Seeing, however, that side-bone constitutes one of the
recognised hereditary diseases, and that at the various agricultural and
horse shows its existence or otherwise in a certain animal is a matter of
great importance, some little attention must be given to these two points.
With a side-bone anywhere approaching full development, diagnosis is easy.
The thumb is pressed into the coronet over the seat of the cartilage, when,
in place of the elasticity we should normally meet with, we have the solid
resistance offered by bone. In some instances diagnosis is even easier
still. We refer to those cases in which the side-bone stands above the
level of the coronet with such prominence as to be readily _seen_ and
recognised without manipulation, and where its growth has caused distinct
enlargement and bulging of the wall of the affected quarter. It seems that
in such cases the bone-forming process does not end with simply depositing
bone in place of the removed cartilage, but that, after that is
accomplished, the bone still continues to be produced, as in the case of an
exostosis elsewhere.
Although diagnosis in cases such as these is easy, it becomes a very
different matter when we are called upon to give an opinion in cases where
ossification of the cartilage is only just commencing. Whether the result
of our examination is to decide the sale or purchase of an animal, to
determine his fitness or otherwise to enter the show-ring, or to merely
advise a client as to whether or no a side-bone is in course of formation,
our position is equally difficult, and in either case our examination must
be searching.
Perhaps the best advice we can give is to say that the whole of the
cartilage must be manipulated both with the foot _on_ and _off_ the ground.
What the reason may be we do not pretend to say, but it is a well-known
fact that in many instances the cartilage, with the foot bearing weight,
is so rigid as to at once convey the impression that ossification has
commenced or is even far advanced. And yet that same cartilage, with the
foot removed from the ground, is as pleasantly yielding to pressure of the
thumb as the most exacting of us could wish for. In any case, then, where
doubt exists, the foot should be lifted to the knee, and the cartilage
carefully examined with the foot in that position. If, then, at any spot
above the normal contour of the os pedis we meet with hardness or rigidity,
we are to look upon that foot with suspicion. Nevertheless, providing our
conscience is sufficiently elastic, the animal may be passed _sound_ so far
as the _existence_ of a side-bone is concerned. We know, however, that with
commencing rigidity we may ere long expect one, and if our opinion is asked
with regard to that particular, it must be admitted that with rigidity of
the cartilage once commenced it is usually not long afterwards before a
fully-developed side-bone makes its appearance.
As is only to be expected, the first noticeable hardening of the cartilage
is to be found near the normal bone. We may thus look for it more
particularly in the lower portions of the cartilage. We think we may say,
too, that in the vast majority of cases the ossification of the cartilage
commences in its anterior half. It is thus brought about that often we
are called upon to examine and report on the condition when we have
_anteriorly_ a side-bone in course of formation, and _posteriorly_ a
perfectly normal cartilage. It is to the latter half of the cartilage that
dealers and others mainly, if not wholly, devote their attention. A horse
with the cartilage in this transition state will therefore pass muster, and
a nice little point of ethics has again to be decided by the veterinary
surgeon before giving his signature to a certificate of examination of an
animal in this condition.
With regard to alteration in gait, we may say at once that side-bones in
heavy animals are not often the cause of lameness. In fact, where the foot
is well developed, when neither the foot as a whole nor the phalangeal
bones give evidence of disease, and where the pasterns are fairly oblique
and well formed, this alteration of the cartilages may be looked upon as of
no serious import at all. Neither is the side-bone due to blows or other
injuries likely to be productive of lameness--that is, always supposing, of
course, that the foot in other respects is of good shape. If lameness is
met with at all, then it is where we have a foot that is in other respects
unsound, with badly contracted heels and upright 'stumpy' hoof, or where
side-bones have occurred in a young animal, and have already reached a
large size before the horse is put to labour. In this latter case, the
added effects of concussion and the evil influences of shoeing are
sufficient to turn the scale. Directly the animal, previously sound, is
asked to work, lameness is the result.
It follows, therefore, that side-bone in the feet of young animals is of
far more serious import than when occurring in older horses. In a nag
animal they constitute a positive unsoundness, and lameness in this case is
more often than not an accompanying symptom.
_Causes_.--To commence with, we may remark that, although met with
sometimes in very early life, side-bones are seldom, if ever, congenital,
and that more often than not they may be looked for in animals of three
years old, or older, seldom earlier. They appear, in fact, only when the
animal is shod and commences work.
This at once suggests two of the principal factors in their
causation--namely, concussion and loss of normal function. Directly the
horse is put to work he has for a great part of his time to travel upon
roadways--either macadamized roads or town sets--where everything is
calculated to bring concussion about. In addition to that he has the
lateral cartilage itself thrown largely out of action by shoeing. We
explained in Chapter III. (p. 66) that the chief function of the cartilage
was to take concussion received by the plantar cushion and direct the
greater part of it outwards and backwards. Now, with the animal shod, the
plantar cushion does not itself, as normally it should, receive concussion.
By the shoeing the frog is lifted from the ground, and the plantar cushion,
together with the cartilage, taken largely out of active work. In other
words, the normal outward and inward movements of the cartilage are
enormously reduced.
It is fair, we think, to take it that the mere fact of the lateral
cartilage persisting _as_ cartilage is due in large measure to its constant
movement. Directly, therefore, it is placed in a state of comparative
idleness, then it commences to ossify, more particularly if there should at
the same time be a tendency to a low type of inflammation of the parts.
Does this latter exist? We may safely say that it does. It is in this way:
The secondary effect of loss of ground-pressure upon the frog and plantar
cushion is to bring about contraction of the heels. With this we get
compression of the parts within, with a certain amount of irritation and
the exact low type of inflammatory phenomena calculated to assist in the
bone-forming process.
The fact that concussion acts as a cause explains in great measure how it
is that side-bones are more frequent in cart animals than in nags, and also
why they should be more common in the fore-feet than in the hind. Taking,
in both animals, a rough calculation as to the weight of body carried
by feet of a certain size, we notice at once that the cart animal has
proportionately more weight to carry than has the nag. Concussion to the
foot is therefore greater. The greater part of the body-weight is borne by
the fore-limbs. Concussion is therefore greater to the fore-feet than to
the hind.
This, however, does not explain altogether the comparative immunity of the
nag animal from this defect. He, too, must also be subject to the effects
of concussion, especially when his higher and faster action is taken into
account. To our minds there is only one explanation to be offered here. We
point at once to the years of constant and judicious breeding of the nag.
Compare that with the relatively few minutes that have been devoted to a
more careful selection of the cart animal, and we at once see a possible
explanation. That the explanation holds some amount of truth is borne out
by the fact that, since a greater attention has been paid to the selection
of our cart animals, side-bone has grown a great deal less common.
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