CHAPTER IV.. Digestive Apparatus.

DIGESTIVE APPARATUS.

RINGING PIGS.

This operation is customary in countries where pigs are allowed to roam more or less at liberty, and it is necessary to adopt some precaution to prevent them from uprooting the soil and thus causing damage, but the practice tends nowadays to disappear. It simply consists in passing through the nose some object which on being rubbed against anything causes pain and thus checks the animal’s natural proclivity.

Numerous methods have been suggested. One of the simplest is as follows: The animal having been cast, suitably secured and muzzled, two thick iron wires sharpened at the ends are passed through the snout, and the two ends are then twisted together in the form of two rings. These can, if necessary, be united.

Another method, perhaps even more efficacious, consists in bending a thick wire into the shape of the letter =U=, and preparing a small metal plate with two holes corresponding in position to the distance between the two nostrils. The ends of the wire, being sharpened, are passed through the nostrils and securely united to the metal plate by being bent into a spiral or simply at right angles.

ŒSOPHAGUS.

The operations practised on the œsophagus comprise passage of the œsophageal sound or probang, taxis, crushing of foreign bodies within the œsophagus, and œsophagotomy.

PASSING THE PROBANG.

Passage of the probang is called for in cases of marked tympanites, suspected dilatation or contraction of the œsophagus, and accidental obstruction. Special or improvised instruments may be used, according to circumstances.

The animal is secured in a standing position with the head extended on the neck and in a straight line with the body. A gag is placed in the mouth and the tongue is grasped and withdrawn by an assistant, whilst the operator, having carefully oiled the probang, passes it through the gag towards the back of the pharynx. Violence should be avoided, the probang being gently slid along the centre of the vault of the palate. When the animal makes swallowing movements, the apparatus is slowly pushed onwards.

This manipulation, though simple, requires some dexterity, because at the moment when the instrument enters the pharynx the animal often thrusts it to one side or the other with the base of its tongue, bringing it between the molar teeth, and so crushing, or at least injuring it.

The passage of hollow probangs gives comparatively little relief in cases of tympanites, because the probang is almost always obstructed by semi-digested material from the rumen, or plunges into the semi-solid masses of food contained therein.

When the œsophagus is dilated at a point within the thorax, the progress of the probang is checked by the accumulated food material, and it becomes possible to determine approximately the place where the dilatation occurs. In the same way, should a slender probang be arrested at a given point in the œsophagus, this indicates that there is contraction of the tube at that point.

In cases of obstruction the cupped probang is always arrested by the foreign body. Efforts to thrust the latter onwards should always be made with great caution, otherwise the œsophagus may be greatly distended or its walls even ruptured.

CRUSHING THE FOREIGN BODY.

No attempt should be made to crush a foreign body within the cervical portion of the œsophagus unless it is quite certain that that body is of comparatively soft character. Crushing may be performed by lateral pressure with the fingers within the region between the two jugular furrows, or mechanical means may be adopted.

In the latter case a small piece of board is applied to one side of the neck behind the foreign body, whilst gentle blows are given from the opposite side with a little wooden mallet. Whatever precautions may be taken, however, this method cannot be recommended.

The same remark applies to the use of forceps, the jaws of which are so fashioned as to escape pressing on the trachea whilst they grasp directly the foreign body through the walls of the œsophagus.

ŒSOPHAGOTOMY.

Œsophagotomy, or incision of the œsophagus, is an operation which, though sometimes necessary, should only be regarded as a last resort after all other methods have failed. Unfortunately it can be performed only in the region of the neck, and even then the most favourable point (viz., the lower third of the jugular furrow) cannot always be selected, the operation having to be performed directly over the foreign body.

The animal may be either standing or lying down. The seat of operation should be thoroughly cleansed and disinfected.

=First stage.= Incision through the skin and subcutaneous connective tissue above the level of the jugular vein and opposite the foreign body.

=Second stage.= Isolation of the œsophagus by dissection and tearing through of the connective and fibro-aponeurotic tissue at the base of the jugular furrow.

=Third stage.= Incision through the œsophagus for a distance just sufficient to enable the foreign body to be extracted.

=Fourth stage.= Suturing of the mucous membrane, suturing of the muscular walls of the œsophagus, suturing of the skin, precautions being taken to allow of drainage at the lower part of the operative wound.

SUB-MUCOUS DISSECTION OF THE FOREIGN BODY.

As œsophagotomy, despite every precaution, often leads to fistula formation, Nocard has recommended submucous dissection of the obstructive body, such body being usually semi-solid. This method has considerable advantages.

The first and second stages of the operation are exactly the same as those above mentioned.

The third stage consists in puncturing the walls of the œsophagus with a straight tenotome immediately behind the foreign body, as in tenotomy. A curved, button-pointed tenotome having next been introduced and passed with the blade flat between the foreign body and the mucous membrane of the œsophagus, it is turned on its axis, and attempts are made to divide the obstruction. A few moments are often sufficient to effect this, after which the substance may be further broken up by the fingers.

These various methods may lead to delayed complications, such as dilatation or contraction of the mucous membrane of the œsophagus, muscular atrophy of the œsophageal walls, œsophageal fistula, and, sometimes, abscess formation.

RUMEN.

Two operations are currently performed on the rumen, puncture and gastrotomy.

PUNCTURE OF THE RUMEN.

Puncture of the rumen is essentially an urgent operation for the relief of acute and rapidly progressive tympanites. It is performed in the left flank, at an equal distance between the last rib and the angle of the haunch, and an inch or two beyond the transverse processes of the lumbar region.

=First stage.= Incision of the skin to the extent of about one inch (not absolutely necessary).

=Second stage.= Puncture with a sharp trocar directed forwards, downwards, and inwards. In making this puncture the point of the trocar is passed through the incision, and a sharp push is given. The sensation of resistance overcome indicates that the trocar has penetrated the cavity of the rumen. Gas then escapes. When the operation is completed, and the canula is being withdrawn, care should be taken to press down the skin on either side with the fingers of the left hand, to prevent accidental lifting and laceration of the connective tissue. Even so slight an accident as this might cause serious complications at a later stage.

In the absence of a trocar, and in cases of extreme urgency, the rumen may be directly punctured with a straight bistoury, and after the punctured wound is slightly enlarged, but before the blade of the bistoury is withdrawn, an improvised canula, consisting of a hollow elder twig, may be introduced. Were the blade of the bistoury withdrawn before the introduction of the canula, the rumen would be displaced, and the points punctured would no longer correspond.

=Complications=, such as respiratory or circulatory syncope, attacks of vertigo, etc., have been noted, but these in reality are very rare.

=Subcutaneous Emphysema.=—When the canula is carelessly removed, and the subcutaneous connective tissue is torn, local emphysema may occur if the pressure of gas in the rumen is very great. This gas enters the puncture, proceeds along the connective tissue, particularly the subcutaneous connective tissue, and causes crepitant subcutaneous emphysema, very easy to recognise. This emphysema may remain localised in the neighbourhood of the puncture and gradually become absorbed. It may, however, extend to the whole of the flank or even beyond, and in exceptional cases bring about generalised subcutaneous emphysema. Such very extensive emphysema as this rarely becomes reabsorbed without complications.

=The suppuration= which follows puncture of the rumen may assume one of two forms:—

(a) That of a little local abscess at the point of puncture, when foreign matter or the microbes of suppuration have been left in the path made by the withdrawal of the canula. Such abscesses are of little importance. They rapidly heal if opened and treated with antiseptic injections.

(b) That of diffuse subcutaneous or interstitial suppuration following accidental emphysema.

The pressure of gas forces fragments of food material between the layers of tissue, and suppuration is set up, the pus escaping by a fistula at the point of puncture. Such suppuration is decidedly dangerous, because it may result in necrosis of the aponeurotic layers of the small oblique muscle, in which case recovery is tedious and uncertain.

=Treatment= consists in laying open the orifice and fistula, and making a counter-opening at the lowest point of the swelling. Free drainage and abundant irrigation with boiled water at the body temperature, followed by antiseptic injections, complete the treatment.

=Peritonitis= is not altogether exceptional as a sequel to puncture of the rumen, if ordinary precautions are neglected or if infective material or fragments of food pass into the peritoneal cavity.

At first the condition is usually local, but it may extend and assume the form of general peritonitis two or three weeks later. The symptoms are those of acute peritonitis.

Speaking generally, however, puncture of the rumen in cattle and sheep is seldom followed by any complication.

GASTROTOMY.

Gastrotomy is performed for the relief of impaction of the rumen and to remove foreign bodies, such as linen, nails, bits of leather, etc., which have been swallowed.

A vertical or slightly oblique incision is made in the left flank, extending from the fourth transverse process of the lumbar vertebræ towards the last rib. The operation comprises the following stages:—

=First stage.= Incision through the skin for a distance of from 6 to 10 inches, according to the size of the animal.

=Second stage.= Incision through the muscles and peritoneum and torsion of any small muscular arterioles, which may be divided.

=Third stage.= Fixation and immobilisation of the rumen with from four to six sutures (Fig. 303).

=Fourth stage.= Vertical incision into the rumen; manual examination of the cavity and its contents.

Formerly the operation was confined to these stages. In such cases localised adhesive peritonitis follows, causing the rumen to adhere to the internal surface of the abdominal wall, and the fistula continues in existence for months before complete cicatrisation. It is better, therefore, to insert sutures in the rumen, in order to secure more rapid and complete closure.

=Fifth stage.= Suture of the rumen with carbolised silk. The lips of the wound should be brought together face to face, or they can be slightly inverted, but the sutures should only pass through the peritoneum and muscular coats, avoiding the mucous coat. If the silk threads pass through the mucous membrane and come in contact with the gas in the upper zone of the rumen they are rapidly macerated, and the sutures tear out before the wounds can heal. The rumen should always be kept fixed to the abdominal wall towards the upper and lower extremities of the operative wound, in order to avoid displacement and occurrence of peritonitis. For a similar reason the passing of the silk sutures should be preceded by careful disinfection of the operative wound, and free washing of the parts with boiled water.

The operation is concluded by bringing the skin together with a few silk sutures and inserting a strip of iodoform gauze into the lower portion of the wound, to serve as a drain.

LAPAROTOMY.

Laparotomy is comparatively seldom performed on animals of the bovine species, though it may become necessary in dealing with cases of hernia, uterine torsion (where direct taxis is called for), Cæsarean section, invagination or strangulation of the intestine, and under a few other exceptional circumstances.

If simple exploration is aimed at, the operation is most conveniently performed from the right flank with the animal in a standing position, but should a prolonged operation be contemplated the animal should be cast. The incision varies in length, according to circumstances, from 8 to 16 inches, and, like that in gastrotomy, should correspond in direction with the fibres of the small oblique abdominal muscle; the seat of operation should previously be washed, shaved, and disinfected.

The operation comprises the following stages:—

=First stage.= Incision of the skin.

=Second stage.= Incision through the muscles and peritoneum.

=Third stage.= Exploration, inspection, palpation, extraction or ablation, etc.

=Fourth stage.= Suture of the peritoneal opening, the lips being brought together face to face.

=Fifth stage.= Suture of the muscles and the skin. It is sometimes advisable to insert a drain of iodoform gauze under the skin.

In small animals, such as the sheep, goat, and pig, laparotomy is more easily practicable, and can be performed either in the right flank or towards the white line. The stages of operation are exactly the same, but after operating near the white line it is extremely important to use numerous and strong sutures, and afterwards to apply a suspensory bandage around the abdomen, securing it above the loins.

HERNIÆ.

The situation and nature of the hernia determine whether or not a radical cure should be attempted.

When a decision has been arrived at the seat of operation must first of all be thoroughly cleansed and disinfected. The animal is cast in a convenient position, and a general anæsthetic is given or a subcutaneous injection of 1 per cent. cocaine solution administered.

The operation comprises:—

=First stage.= Incision through the skin covering the hernial sac, opposite the orifice of the hernia.

=Second stage.= Isolation of the hernial sac.

=Third stage.= Reduction of the hernia and breaking down of any adhesions that may exist.

=Fourth stage.= Resection of the sac and obliteration of the peritoneal orifice by suture and ligature.

=Fifth stage.= Suturing of the muscles and skin, and application of a surgical dressing.

In practice, the deep sutures should be of bichromatised catgut or silk, and the skin sutures of catgut ligature or aseptic silk.

INGUINAL HERNIA IN YOUNG PIGS.

One of the most frequent forms of hernia which the practitioner is called on to treat is inguinal hernia in young pigs. Although this allows little tendency towards strangulation it is always desirable to operate, as otherwise the patients develop badly. There is no difficulty in this, though the animals must be cast and placed on their backs, the hind quarters being raised (Fig. 305).

=First stage.= A longer or shorter cutaneous incision over the neck of the hernia and along its greater curvature.

=Second stage.= Isolation of the hernial sac, consisting of the dilated internal sheath.

=Third stage.= Direct reduction of the hernia without opening the sac, provided no adhesions occur, or, in the event of adhesions, after incision of the sac.

=Fourth stage.= Torsion of the hernial sac and of the testicular cord up to the inguinal ring. Application of a catgut or silk ligature around the sac and cord at the level of the inguinal ring.

=Fifth stage.= Fixation of the ligature to the lips of the ring. Suture of the skin wound, and drainage of the wound with a strip of iodoform gauze.

IMPERFORATE ANUS.

This anomaly of development, which is not uncommon, presents two different degrees of development.

In the first degree the rectum is well formed, and extends as far as the skin below the base of the tail.

In the second the rectum is incomplete or non-existent, the floating colon terminating in a blind end at the entrance to the pelvis.

In calves, lambs, and young pigs very often imperforate anus is not diagnosed until the second or third day after birth. Defæcation cannot occur, and death is inevitable unless an artificial anus be established.

FIRST DEGREE.—The patient loses appetite, the abdomen remains distended, and on examination of the anal region a doughy swelling is felt, which projects backwards when the animal strains. The operation is quite elementary, and always proves successful.

=First stage.= The skin beneath the tail is incised vertically; the rectal cul-de-sac projects towards the incision.

=Second stage.= The rectal cul-de-sac is punctured, the contents are removed, and the rectum and skin united by a few sutures. An anus is thus established, though there is no sphincter.

SECOND DEGREE.—The general symptoms are similar, though very often the little patient shows symptoms of atrophy or arrest in development. The operation is somewhat complicated.

=First stage.= Vertical incision through the skin at the base of the tail.

=Second stage.= Digital exploration of the cavity of the pelvis after breaking down of the layers of connective tissue, and search for the blind end of the floating colon. When discovered, the colon is grasped between the jaws of a clamp or large forceps with smooth jaws, and gently drawn towards the opening.

=Third stage.= Puncture of the blind end of the colon, and suture of the latter to the cutaneous wound, as in the former case.

A third condition may exist, where the extremity of the colon remains within the abdomen. Operation by way of the pelvis then proves unsuccessful. If considered advisable, an opening may be made through the right flank, so that the floating colon may be brought to the surface and an artificial anus produced in this region.

An incision 1 or 2 inches in length is made below the haunch, to allow of the introduction of the index finger, with which the loop is sought. The colon is withdrawn, and the operation thenceforth is as above described.

PROLAPSUS AND INVERSION OF THE RECTUM.

This condition occurs in young pigs in various degrees. The necessity for reduction depends on the extent to which tearing or gangrene of the mucous membrane has progressed. The inverted portion is carefully washed, freely dressed with some non-irritant fatty substance such as vaseline, and progressively pushed back with the thumbs and index fingers of both hands applied flat on either side of the anus. To facilitate reduction it is best to check the animal’s expulsive efforts by placing a gag in the mouth.

In more aggravated cases, when prolapsus of the rectum has returned several times and the mucous membrane is gangrenous in places so that such a complication as peritonitis of the pelvic cavity is to be feared, it is better to amputate the prolapsed portion.

The animal is secured either standing or lying down, and a large enema is administered to remove the contents of the rectum. The herniated portion of bowel is carefully examined, for it sometimes happens that loops of intestine have become lodged in the dilated peritoneal sac, produced by displacement of the rectum. In such cases reduction should be effected before anything more is done, and for this purpose the patient’s hind quarters should be lifted or even suspended.

The operation for removal comprises two stages:

(1.) Fixation of the two layers of bowel by the passage of either two or four sutures about ½ an inch behind the anus.

(2.) Circular amputation of the sutured tissues; insertion of interrupted silk sutures through the lips of the wound; reduction. The patient is restricted to milk diet for a week. Laxative gruels, etc., may then be given.

The complication to be feared is peritonitis of the pelvic cavity owing to the sutures tearing out and allowing infective material to pass from the bowel into the cavity.

Slight cases of prolapsus might possibly be treated by the injection in lines of melted paraffin wax beneath the mucous membrane of the last part of the bowel. The injection is made by means of a large syringe provided with a long needle, the needle being gradually withdrawn as the melted wax is expressed. Four “pillars” of wax are usually injected at equidistant points. As they solidify they support the bowel and prevent the recurrence of the prolapse. The operation, however, is delicate, and scarcely to be recommended in pigs. Moreover, in man, in whom it has chiefly been practised, the deferred results have not always proved satisfactory.