FISTULOUS WITHERS AND POLL EVIL Fistulous Withers Under the heading of"Fistulous Withers"all the traumatic lesions of the back and withers which may lead to this condition must be con sidered as well as itself. The lesions which may exist here comprise: (1) Excoriations; (2) a gall; (3) a hnaa toma; (4) a sit-fast or area of necrosis; (5) bursitis; (6) an abscess; (7) an open wound; (8) fracture; (9) a sinus or"fistulous withers." Etiology. All the above affections are of traumatic origin, the injury in most cases being caused by the harness. When an abscess or a sinus supervenes, it is due to infection having gained entrance through a breach of surface of the integument.
There are predisposing causes which deserve to be mentioned, including the following: (1) Low withers, allowing the saddle to be displaced forwards. (2) High withers, which are apt to be compressed by the pommel or front arch of the saddle. (3) Narrow chest, making it difficult to tighten the girths, and causing the saddle to move during work. (4) Poor condi tion of the animal leaving the bones insufficiently covered or cushioned by soft tissues, and making the spinous processes of the vertebrae more prominent. (5) Faulty adjustment or con struction of the saddle. (6) An awkward or tired rider who does not balance himself properly, thus causing unequal distribution of the press ure on the back and displacing the saddle. (7) Working in hilly country causing movement of the saddle during the ascent and descent of slopes. (8) Ill - balanced pack saddles. (9) Sweating, or the skin being wet from rain, caus ing it to adhere to the lining of the saddle and to move with the latter, thereby rupturing the cutaneous or subcutaneous fibrous tissue, and giving rise to infiltration of serum therein and the formation of a gall.
When there is a combination of these circum stances, bad effects are more likely to be pro duced.
1. Excoriations are due to chafing by move ment of the saddle, the epithelium becomes softened by the sweat and detached from the corium, which appears red and inflamed, and covered with an exudate which afterwards dries to form a scab. The affected part is very sensitive and the animal resents its back being touched.
Treatment. Consists in applying an anti septic powder and resting the subject until the lesion heals under a scab.
2. Galls are the result of contusion or excess ive pressure of the saddle on the affected parts, or of laceration of the cutaneous or subcutan eous fibrous tissue due to adhesion of the skin to the lining of the harness, and movement of the latter. Infiltration of serum takes place into the cutis or subcutis or beneath the fascia, causing the formation of raised circular inflam matory areas, varying in dimensions from a shilling to a five-shilling piece, easily felt by passing the hand over the saddle-seat, and painful on pressure.
The gall may not form until after the saddle has been removed, when it is caused by the inrush of blood to the capillaries, which have been paralysed by pressure and consequently dilate excessively or rupture with the results mentioned.
Subfascial galls generally occur on the withers, and are the most painful form of the condition. The other varieties are mostly found on the seat proper of the saddle.
Cutaneous galls disappear in the course of eight to ten days, subcutaneous ones are slower in undergoing resolution, and subfascial enlarge ments are still more difficult to get rid of.
Treatment. A gall may sometimes be pre vented by leaving on the saddle for about half an hour after the horse comes in from work, so as to allow the blood to return gradually to the anaemic vessels, and thus prevent their rupture from sudden forcible distension.
When the lesion exists it must be treated as a contusion, first by cold and astringent lotions to prevent further infiltration, and afterwards by moist heat, absorbent topics, and massage to promote absorption of the infiltrate.
3. Haematoma.A hmatoina is a form of gall due to accumulation of extravasated blood in a cavity beneath the skin. When slight it undergoes absorption in the course of some days or weeks, but when large it persists as a sort of cyst.
Treatment. Treatment is the same as in the case of an ordinary gall at first, but when the swelling persists beyond a reasonable time it must be opened and evacuated of the serum and fibrin which it contains, and its lining must be treated with an irritant like tincture of iodine to bring about inflammation, granula tion, and cicatrization.
Strict antiseptic precautions must be taken to prevent sepsis and the possible complication of"fistulous withers." 4. A sit-fast is a patch of necrosis affecting the skin and subcutaneous tissue to a varying depth, due to arrest of the circulation in the affected region by the pressure of the harness.
The necrotic portion is cone-shaped, the base of the cone being formed by the skin. After some days a line of demarcation or reaction forms, at the level of which the dead becomes separated from the living part, a trench being formed in which suppuration takes place.
Treatment. The treatment consists in hasten ing, as far as possible, the removal of the dead tissue. This may be effected by applying a counter-irritant, such as a little biniodide of mercury blister, round the affected part to pro duce hyperaemia and intensify the inflammatory process by the agency of which the slough is cast off.
When the sit-fast is partly detached it should be excised with a knife.
When the trench surrounding the necrotic portion is deep and pus accumulates therein, a counter-opening should be made to provide drainage and prevent further destruction of tissue from stagnation of the pus.
5. Bursitis.In most horses there is a bursa between the funicular portion of the ligamentum nuchae and the spines of the first four dorsal vertebrae. This may become affected with bursitis, causing a fluctuating swelling which is more or less painful, according to the intensity of the inflammation, and is frequently bibbed.
The distension of the bursa may extend be neath the trapezius or rhomboideus muscle. The condition may be confused with an abscess, and diagnosis can only be made certain by an explora tory puncture with a fine trocar and cannula.
Treatment. The lesion must be treated as an ordinary bursitis or inflammatory condition. If it is recent and acute, cold and astringent applications are indicated, which have the effect of allaying the inflammation, but often fail to dispel the swelling, which remains as a cystic enlargement or hygroma, of which the treatment may be: (1) Counter-irritation by a blister or the actual cautery. The former is seldom of much benefit. The latter, especially in the form of penetrating needle-points, is often very effective.
(2) Aspiration and injection of an irritant such as tincture of iodine, pure or diluted with two parts of distilled water. This is often effective, but may require to be repeated several times at intervals of two to four weeks before complete cure occurs.
When the cyst contains solid, rice-like bodies, this line of treatment is of little use.
(3) Incision and evacuation of the contents is the only procedure that can bring about cure of a hygroma containing the solid particles mentioned. It has the disadvantage of expos ing the tissues to infection, which may result in fistulous withers, if careful antiseptic precautions are not observed.
6. Abscess. - An abscess may occur as a primary lesion or be secondary to bursitis or a humatoma from these conditions becoming infected. It may be superficial or deep, and centrally or laterally situated. Strangles may be the cause of an abscess in this situation. Exploratory puncture will confirm the diagnosis when it is doubtful.
Treatment. When the abscess is deep, rub bing in a vesicant is useful in bringing the pus nearer to the surface before using the knife to allow of its escape. The incision should be made longitudinally, because if made trans versely, it will gape considerably, take a long time to heal, and leave a larger scar. A counter opening may be necessary to provide drainage. If the cavity contain necrotic tissue, it will require to be irrigated once or twice daily with a disinfectant until the interior becomes clean and uniformly covered with granulations. A sinus may supervene constituting"fistulous withers." 7. Open wounds when deep, involving the ligamentum nuchae or supra-spinous ligament or the dorsal spines, are serious as they are very likely to be complicated by necrosis of these structures. They are treated on general principles.
8. Fracture of the dorsal spines is a rare condition due to severe external violence. It may be simple or compound. The former is diagnosed by crepitation, and in the latter the fracture may be visible through the wound.
Simple fracture heals with rest.
Compound fracture may be followed by necrosis of the bone as the result of infection through the open wound.
Treatment. Treatment is only necessary for compound fracture, to prevent sepsis by dis infection of the wound, and to remove loose splinters of bone if present.
Fistulous withers is a sinus in the region of the withers. It is due to a traumatic lesion becoming septic and the bacteria reaching the deep-seated structures of feeble vascularity, which consequently undergo necrosis, causing constant suppuration and perpetuating the condition until the necrotic tissue is removed. The structures involved may be the subcu taneous fibrous tissue, the ligamentum nuchm, the supra-spinous ligament, the dorsal spines, the dorsal transverse processes, the upper part of the ribs, the cartilage of prolongation of the scapula, and the scapula itself.
Symptoms. The symptoms are those of a sinus associated with more or less severe inflam mation. There is one or more orifices dis charging pus. Exuberant granulations may be present at the entrance to the sinus. The swelling, usually well marked, is always very sensitive to the touch, and is situated in one or both sides of the middle line. The depth of the lesion varies in different cases. A probe passed in through the opening may fail to reach the extremity of the cavity owing to the passage being tortuous. The pus may burrow down wards to near the level of the elbow.
Some of the openings may have healed, while new ones have formed by the bursting of secondary abscesses. When the lesion is long standing the affected tissues become indurated. When the discharge is copious it indicates that there is extensive destruction of the deep-seated structures.
Prognosis. Generally speaking, the prognosis should be guarded. The condition is always troublesome and tedious to deal with. It usually necessitates extensive incisions to expose the diseased tissue and permit of its removal, and to provide for drainage. When this is effectively done, healing takes place within a period of two to six weeks, depending on the depth and area of the affection. When the bone is diseased the case is more serious because of the depth of the lesion, and the tendency of the osseous tissue to be reinfected after its necrosed surface has been curetted or scraped. When suppuration extends deeply to the inner aspect of the scapula, it is difficult to treat the con dition satisfactorily, and when this bone is affected with necrosis it may be hard to locate the seat of the disease, and its effective treat ment requires a drastic use of the knife, and the formation of alarming wounds which will take weeks to heal.
The case may appear to do well for a while, when renewed inflammation occurs owing to the formation of a secondary abscess due to re infection, or to a portion of necrotic tissue having escaped detection at the time of operation, and being left in situ. Rarely the intervertebral ligament is penetrated, leading to paralysis and death from interference with the spinal cord. The patient, in bad cases, loses condition as the result of pain and toxaemia, and may succumb to the latter or to pyaemia or septicaemia.
Treatment. The principles of treatment are simple, being those of a sinus, and comprising: (1) Antiseptic injections, which may be suffi cient to overcome the bacteria in a recent case, while the necrotic tissue separates and comes away with the discharge. They are generally disappointing.
(2) Caustic injections, composed of perchloride of mercury, 1 to 10 of spirit, chloride of zinc, 10 per cent; saturated solution of sulphate of copper or sulphate of zinc, etc., which are often effective, promoting separation of the diseased parts, and having powerful germicidal properties.
(3) The use of solid caustics such as corrosive sublimate, sulphate of copper, or chloride of zinc pushed into the depth of the cavity, where they cause an eschar or core which on separating takes with it the original necrotic tissue, leaving a healthy granulating wound, provided that the agent reaches the affected parts. It is generally necessary to enlarge the opening of the sinuses to enable the drug to be satisfactorily intro duced.
a caustic, through the sinus, to produce the effect mentioned in No. 3, and to act as a drain by keeping the openings patent.
(5) Operation to open up sinuses, expose and remove necrotic callous tissue, to scrape necrosed bone and, if necessary, to make counter-open ings, strict antiseptic precautions being taken to prevent reinfection.
A careful search is often necessary to prevent secondary passages being overlooked. Cavities should be plugged with antiseptic gauze, wool, or tow to arrest the haemorrhage and keep their walls apart until the following day, when the plug should be removed. The use of the syringe is indicated to flush out debris after operation. Tincture of iodine is a useful preparation for swabbing the interior of the wound after ex cision of the diseased tissue.
The after-treatment comprises daily irrigation with an antiseptic solution and the insuffiation of an antiseptic powder such as a mixture of iodoform and boric acid, or permanganate of potash and boric acid or 1-20).
When the wound is granulating uniformly the lotion should be discontinued, except for appli cation to its periphery, but the dry dressing should be continued until healing occurs. Vase line should be smeared beneath the wound to prevent discharge adhering to and excoriating the skin.
When there is a lesion of the bones it is advis able to cover the withers with a sterilized pad, made by stitching a layer of cotton-wool covered by gauze to a clean stable-rubber. The latter is fixed in position by means of a roller placed behind the wound and by strings round the neck. If a protection of this kind is not afforded, it is difficult to prevent contamination of the wound in the bone from the dust in the stable, especially when situated on a prominent dorsal spine which is not covered by skin.
(6) The use of bismuth paste, composed of wax, vaseline, paraffin, and subnitrate of bismuth. This is recorded as having had excellent results in the treatment of sinuses in various parts of the body. The necrotic tissue should be removed before introducing the preparation.
(7) Carrel's tube treatment of septic wounds by continuous antiseptic irrigation, as carried out by Captain Peatt, A.V.C., in Salonika, and described by him in the Veterinary Journal (Vol. 74, No. 4).
This treatment has had remarkable success in the hands of Captain Peatt.
(8) The use of an autogenous vaccine, which is often very effective, causing prompt healing of the lesion.
(9) The hypodermic injection of nuclein to increase phagocytosis and counteract the effects of the bacteria. It has often proved very beneficial.
The term"poll evil"is sometimes applied to any inflammatory affection of the poll, but the typical condition which has given rise to the name is a sinus in this region.
The lesion on the poll may be: (1) A con tusion; (2) a hwmatoma; (3) a sit-fast; (4) an open wound; (5) a bursal enlargement; (6) an abscess; (7) a sinus.
The subject might be briefly dealt with by referring the reader to the general surgery of these conditions.
They are all due originally to direct injury of the region such as may be caused by a blow, striking the poll against the manger, the top of a doorway, a ceiling, or the roof of a pit, or something dropping from the latter on the poll, falling backwards the occipital region striking the ground, or the pressure of a heavy bridle or a tight overcheck. An abscess and a sinus are due to the entrance of infection, which in the latter case causes necrosis of the ligamen tum nuchze, and sometimes necrosis or caries of the occiput or atlas as well.
Each of the above conditions is dealt with in dividually in the preceding article on"Fistulous Withers,"and they are practically the same occurring on the poll.
Symptoms. The symptoms vary according to the nature of the affection, but in every case there is more or less interference with movement of the head on the neck, the patient holding the former stiffly at a lower level than usual with the nose poked forwards. In acute inflam matory lesions this interference with movement is very striking and pain is very intense, the animal resenting the slightest pressure on the affected part.
In the case of a sinus or typical"poll evil"there is a more or less extensive inflammatory swelling on one or both sides of the middle line showing one or more purulent orifices. The strong funicular portion of the ligamentum nuchw prevents distension of the mesial aspect of the region.
When the disease is long in existence the enlargement is indurated, due to the develop ment of a large amount of fibrous tissue. The discharge is always copious owing to the great destruction of tissue in the depth of the lesion.
A probe passed into the sinus gives an idea of the extent of the purulent cavity, and if the bone is affected it may grate on its rough surface.
Exceptionally the occipito-atlantoid articula tion becomes affected with a dry arthritis which results in anchylosis of the joint, and incurable rigidity of the head on the neck. Secondary deep-seated abscesses may form causing intense pain during their development, and giving rise to febrile disturbance. The subject then stands motionless with the head low and extended, and sometimes resting on the manger. When the abscess bursts considerable relief is obtained. Pressure of a deep abscess may be transmitted through the thin occipito-atlantoid capsular ligament to the spinal cord and cause paralysis. Rupture of this ligament may rarely supervene, and lead to sudden death from interference with the central nervous system.
Treatment. The treatment will vary accord ing to the character of the condition as described in the case of Fistulous Withers. Incision for an abscess or the enlargement of an opening or the production of a dependent orifice should be made longitudinally in.. order to have as little gaping of the wound as possible, and thus favour cicatrization afterwards.
When a recent abscess is opened healing may occur at once, or more commonly a sinus super venes owing to the presence of necrotic ligament.
It is impossible to get perfect drainage from a cavity abutting on the occiput, as there is no way of making an outlet laterally, and the occipital crest forms a barrier in front.
Despite this, however, recovery may super vene provided that necrosis is absent. In every case of a sinus the ligamentum nuche is necrotic, and cure is impossible until the dead portion is removed. This may be effected by the use of solid caustics or a caustic seton, but the surest procedure is to operate as follows: Clip off the mane and forelock and the hair in the vicinity of the affected region, and shave the skin on the middle line from a point in front of the occiput to a point behind the posterior extremity of the lesion, that is, over the site of the operation. Disinfect the latter. Cast and anesthetize the horse, and fix him in the lateral position with the poll supported on a pillow formed by a sack of hay. Make a mesial longi tudinal incision through the skin and adipose tissue down to the ligamentum nuclue, a depth of a couple of inches of fibrous tissue being gone through sometimes before the latter is reached.
Cut the cord of the ligamentum at its insertion into the occipital crest. Dissect it backwards as far as it is diseased and then excise it.
The affected part is burrowed by sinuses discoloured and disintegrated.
Having removed every trace of necrotic tissue and opened up every sinus and scraped the bone, if affected with caries, flush out the cavity with an antiseptic solution, swab sus picious parts or the whole of its lining with tincture of iodine, dust it with an antiseptic powder, and arrest the diffuse hemorrhage by plugging the wound with gauze, cotton-wool, or tow, kept in position by sutures. Remove the dressing next day and treat afterwards as an exposed open wound, irrigating it daily with an antiseptic lotion, and covering it with dry dress ing until it becomes lined uniformly by granula tions, when the lotion should be discontinued and the antiseptic powder only applied.
Occasionally, owing to the bleeding concealing the field of operation, a portion of necrotic tissue is left in situ, so that it may be necessary to cast the patient again in the course of a few days in order to remove it.
When this operative procedure is correctly carried out cure is obtained after a period of four to eight weeks, depending on the size of the wound.
The evidence of pain diminishes and the animal moves the head more freely. Although the funicular portion of the ligamentum nuche has been severed and partially excised, the head is held at a higher level after than before the operation, owing to the relief of tension caused by the latter. It has been said that section of this cord causes the head to droop owing to the consequent loss of its automatic supporting effect, but experience proves that this is not the case. Should some necrotic tissue have been left in the sinus, inflammatory symptoms will recur due to the formation of an abscess, requiring renewed intervention to remove the cause of the condition.
A modification of the above method of treat ment is to cut a channel through the occiput crest by removing a V-shaped piece of bone therefrom by means of a gouge or fine saw, as recommended by Williams of New York, the object being to permit of drainage over the face.
It is not essential to success, and has the dis advantage of wounding the bone and exposing it to infection by the discharge from the lesion.
The use of an autogenous vaccine often has a marked curative effect, and the hypodermic injection of nuclein is reported as having had excellent results in accelerating recovery. The injection of a paste into the sinus, or Carrel's tube treatment of septic wounds by continuous antiseptic irrigations, are methods of treatment which are indicated here as in Fistulous Withers.
The patient should be kept in a hygienic loose-box, and its food should be placed at a convenient level. The hay should not be put in a rack.
After cicatrization of the wound has occurred, the cicatricial contraction may prevent the animal's head reaching the ground to graze. This must be borne in mind when contemplating putting the horse to grass.