◊ Abdominal Wall Affwctions & Hernia ◊

AFFECTIONS OF THE ABDOMEN

I-OPEN WOUNDS

1-NON PENETRATING WOUNDS

Definition: -

Superficial wounds that don’t divide or penetrate abdominal wall, don’t likely to be followed by further laceration of the abdominal walls, and neither associated with prolapse or injury of internal organs.

Treatment: -

These wounds merely require to be kept clean, and are treated on aseptic principles according to the condition of the wound (recent or old). Such wounds generally heal well if freely dressed with antiseptics. If infection or suppuration extends, counter-openings or drains are resorted. When the walls are extensively lacerated, and further laceration is possible, the wound should be carefully sutured, and supported with a bandage. Strong and deeply-inserted stitches are required, and complete rest should be prescribed. Suppuration sometimes occurs between the abdominal muscles. This condition is treated in the same way as infected wounds.

2-PENETRATING WOUNDS WITHOUT PROLAPSE

Definition: -

They are wounds extending to or dividing the parietal peritoneum, neither associated with prolapse nor injury to internal organs. The use of probe is contraindicated, to avoid conveying infective material into the peritoneal cavity, and it has low diagnostic value owing to the layers of muscle being often displaced and occluding the deeper channel of the wound

Causes: -

1-Thrusts with the horns

2-Sharp instruments like stable-forks, lances, bayonets, knives, or scissors

3-Gun-shots

4-Injuries from leaping over hedges or fences, or by falling on sharp objects, as harrows or spurs

5-The bites of dogs may also penetrate the peritoneal cavity

Signs: -

Every penetrating wound of the abdomen must be regarded as dangerous and prognosis principally depends on whether prolapse of the intestine and peritonitis can be prevented.

1-Presence of abdominal wound

2-Perforation may occur without peritonitis, and it may be disclosed by protrusion of abdominal organs, or discharge of the contents of the bowel

3-Penetration of the peritoneum may shortly be demonstrated by symptoms of peritonitis, marked tension of the abdominal wall, increased pulse rate, paleness or dirty red color of the mucous membranes, slight or continuous colic, and vomiting in pets.

Treatment: -

Treatment is directed towards prevention of wound sepsis, peritonitis and prolapse of the intestine

1-Peritonitis may be prevented by following general aseptic treatment of the wound, and massive systemic antibiotics. Careful cleansing and disinfection of the wound according to its state (recent or old) and its neighborhood are necessary, bleeding must be checked by ligaturing injured vessels, and prevent blood accumulation in the wound. Foreign bodies, and loose shreds of tissue, likely to become necrotic, should be removed. The wound is sutured with suitable suture material and pattern

2-Prolapse of internal organs can be prevented by bandages passed around the body of the animal, with keeping him in quiet well-padded place or kept on slings. For several days the food chosen should be digestible, nutritious, and small in amount, and water given only in small quantities

3-PENETRATING WOUNDS WITH PROLAPSE

Definition: -

It is an open penetrating abdominal wound that is associated with prolapse of portions of omentum, bowel, uterus, or other abdominal organ, and constitutes a dangerous complication. The prolapse is not so dangerous, but there is much difficulty in returning and retaining it in position, preventing soiling and injury, and preventing entrance of infective materials into the peritoneal cavity.

Treatment: -

Early reposition is the most important indication, with prevention of viscus injury and soiling.

1-The wound and its neighborhood, together with the protruding portion, are carefully cleansed, any foreign bodies are carefully removed, and the necrotised wound, omentum, or organ is excised.

2-Reposistioning of the prolapsed organ, Omental prolapse is least dangerous, because when its return is difficult or impossible, a large piece may be removed without bad consequences. Bowel prolapse is more dangerous, because when the serosa is injured its vitality is lowered and favors the growth of infective organisms. Prolapses of the large intestine are generally least troublesome. In the horse, prolapse of the colon or cecum, is more easily reduced and kept in position than that of the small intestine, because the colic mesentery is shorter than that of the small intestine, and the viscus is less sensitive to operative interference.

3-Suturing of the wound with suitable suture material

4-Bandage to prevent reopening of the wound and subsequent prolapse

5-Massive dose of systemic antibiotic

6-Digestible, nutritious, and small amount food and small quantities of water for several days

4-WOUNDS WITH INJURY TO INTERNAL ORGANS

Definition: -

It is a perforating abdominal wound associated with injury of internal organs with or without prolapse. In herbivora the colon is most frequently injured, on account of its great area, its distension with hard food, and its fixed position while the more mobile small intestine being generally filled with fluid frequently evades the object producing the injury. Accordingly, pointed instruments may penetrate the abdomen deeply without injuring this intestine.

Treatment: -

1-Suturing the injured organ with suitable suture materials if it is prolapsed, or widening of the wound under aseptic condition, if it is not prolapsed, and then the organ is sutured. The injured organs must be carefully cleansed and foreign bodies are removed, and if there is necrosis or gangrene, the necrotized part should be excised and the bowel is anastomosed. The peritoneum must be washed with normal saline solution.

2-The subsequent treatment has already been described

II-CLOSED WOUNDS

1-HERNIA

Definition: -

Hernia or rupture is a condition in which portions of the abdominal contents have passed through the abdominal walls, and lie under the intact skin. Should they pass through the skin, the condition is called prolapse. The passage of abdominal organs through the diaphragm into the thorax is also described as hernia (diaphragmatic hernia).

Causes: -

1-Congenital like wide inguinal ring or open umbilicus

2-Increase of intra-abdominal pressure, frequent coughing, dyspnoea, pressure on the abdomen, or development of gas in the bowel

3-Rupture of the abdominal wall directly by blunt trauma

ESSENTIAL CONSTITUENTS OF HERNIA

A-Opening In The Abdominal Wall (hernia ring)

It is an opening through which the viscus has protruded, and it may be a normal opening like the umbilicus, or one abnormally dilated, as the inguinal canal sometimes is, or a rupture in the abdominal coats, without solution of continuity in the skin. The rim of this orifice is termed the hernial ring. Its form and size vary greatly, from little finger to a man's fist, and it is round, oval or slit-like.

B-Hernial Swelling

It may vary from the size of a hazel nut to that of a man's head or more, consists of the portion of protruded viscus (hernial contents), and its coverings (hernial sac). The latter is divided into neck and base. The hernial sac consists of skin and subcutis, the latter is usually thickened, and sometimes it has layers of muscle and abdominal fasciae.

CLASSIFICATION OF HERNIAE

A-According To Reducibility

1-Reducible Hernia

This type of hernia can be reduced to the abdominal cavity through the hernia opening (ring), the contents lie free in the sac, and can be returned to the peritoneal cavity.

2-Irreducible Hernia

It is the hernia that can’t be reduced into abdominal cavity either due to large size of the contents and sac than the opening, the hernial contents and sac become adherent to one another, excessive distension of the protruded portion of intestine by gas or hard masses of faeces, or strangulation of the contents.

B-According To Strangulation

1-Non-strangulating

Herniae that predispose to no involvement of blood supply of the hernial contents, and they are less likely to cause death of the animal

2-Strangulating

Herniae that predispose to involvement of blood supply of the hernial contents, and they are likely to cause death of the animal. Hernial ring compresses the contents and interferes with normal passage of ingesta through the intestinal loop. In consequence of this compression the return of blood through the veins is first affected followed by the arteries, whose strong walls and high blood-pressure oppose considerable resistance to compression. Blood continues, therefore, to enter by the arteries even after the inception of strangulation, and soon produces a severe venous congestion, usually associated with more or less extensive rupture of small vessels and hemorrhage. Infective inflammation of the intestinal wall follows, blood-stained serum is exuded, the hernial fluid increases, and in consequence of mixture with blood becomes red in color. The hernial contents, especially the serosa of the intestine, are dark red or black, and this coloration is distinctly and usually sharply bounded by the ring-like circle of compression, which is usually grey and anemic. Both these anemia and venous congestion impair nutrition in the strangulated parts, which if not relieved undergoes necrosis. Stasis predisposes the intestinal contents to putrefy, irritate the mucous membrane, and co-operate with defective circulation in inducing necrosis of the mucous membrane. Necrosis and gangrene are suggested by the presence of offensive fluid or gas in the hernial sac. The anterior portion of the bowel appears greatly distended with food, whilst the posterior portion may be empty and narrower than normal.

Causes of strangulating herniae: -

1-Contraction of the hernial ring by inflammatory swelling near the neck of the hernia

2-Increase in the size of hernia contents

3-Distension of hernia contents so that the hernial ring acts as a ligature

4-Twisting of hernial contents

Signs of strangulating herniae: -

1-Presence of swelling, hernial sac and ring

2-Symptoms of regular colic, and vomiting in pets, the hernia will be found to have increase in its size, become hard, painful, and tenser than formerly.

3-Symptoms of peritonitis, and the animal soon dies if reduction is not effected

C-According To Contents

The contents consist of a loop of intestine (enterocele), omentum (epiplocele), both of intestine and omentum (entero-epiplocele), stomach (gastrocele), uterus, bladder, liver or a serous fluid (hernial fluid).

D-According To Location

1-Internal

These are herniae that can’t be seen outside the abdomen like diaphragmatic hernia. Diaphragmatic hernia usually seen in cattle as a result of ingestion of sharp metallic foreign bodies that lead to traumatic reticulitis and subsequent weakness of the diaphragm, then after the rumen or reticulum can pass through such openings into the thorax.

2-External

These are herniae that pass outside the abdominal cavity through pre-existing opening that undergo widening or induced abdominal defects, and it can be seen outside the abdomen as swellings. Examples of these herniae are umbilical, scrotal or inguinal hernia.

Diagnosis of hernia: -

1-Presence of a swelling free from inflammatory symptoms (especially pain), soft, elastic, and compressible and may be diminished by pressure in case of non-strangulating hernia

2-Non-strangulating reducible hernia varies in size from time to time, increases by coughing or severe exertion with increased abdominal pressure and decreases when intra-abdominal pressure falls

3-In case of reducible hernia, the swelling may completely disappear on pressure, or on placing the animal in a suitable position, and it returns on removal of pressure or alteration of position

4-Irreducibility may be suspected when the hernial swelling undergoes no alteration in size from day to day.

5-Presence of hernial opening that can be felt by thrusting a finger into the depth of the sac, especially after reducing the hernia

6-Examination per rectum is sometimes useful in horses and oxen as the hernia can be reduced by traction on the bowel

7-Exploratory puncture may be helpful in doubtful cases, and for differential diagnosis in case of abscess or hematoma

Prognosis: -

Reducible hernia is not a fatal condition unless strangulation occurs. Prognosis chiefly depends on the probability of strangulation. The smaller the hernial aperture compared with the size of the sac, the greater the danger of strangulation. Small intestine becomes more easily strangulated than colon or omentum. The size of the aperture, and the use to which the animal is put, must be considered, whilst it should be remembered that strangulation occurs more easily in working-horses, and that large herniae may interfere with usefulness.

Many herniae, and especially umbilical and inguinal herniae in young animals, disappear without treatment, and others may last the animal's whole life without interfering with its use.

Irreducible herniae are more dangerous than reducible, recent than old, and intestinal than omental, because in each case the former are more likely to become incarcerated than the latter.

Treatment: -

A-Treatment Of Non-strangulated Herniae

1-Palliative Cure (slight herniae in young animals)

In many cases no treatment is required, because of spontaneous recovery and rare strangulation. Peculiarities of treatment will be separately described in connection with each of the various hernias.

Bringing about a gradual diminution in the hernial sac via suitable dietetic precautions (supplying concentrated and easily digested food), avoiding hard work, and preservation of a suitable position so that the viscera will be removed from the position of the hernia

a-Hernial truss

Trusses don’t have the same effect in domestic animals as in human. They are impracticable for inguinal herniae in animals. Usually they have low success rate in animals than they do in human.

b-Diminution of hernial sac & reduction of contents into abdomen

By induction of inflammatory and cicatricial processes in the skin of the sac by  application of the actual cautery, or by subcutaneous injections of irritants leading to inflammation and swelling in the skin and S.C. and cicatricial contraction that forces contents into the peritoneal cavity.

2-Radical Cure (herniae of elder animals)

The radical cure means closing the hernial opening, and it directed towards removal of the sac and closure of the hernial aperture by causing the hernial ring or the neck of the hernial sac to unite or by other methods.

a-Ligation of the hernial sac

It can be used when the sac possesses a narrow neck, and displacement of ligation can be prevented by trans-fixation transversely through the neck of the sac after reduction of the hernia.

b-Interrupted ligatures

It is used for hernia with broad base. After returning the hernia, strong threads of sterilized silk are passed through the neck of the sac close to the hernial opening in the form of multiple ligations and then the skin of the hernial sac can then be cut through. This method is frequently employed, and usually allows healing by first intention, which greatly tends to ensure success.

c-Surgical reduction and suturing of the ring

This method is performed via positioning the animal in dorsal recumbency, aseptic preparation of surgical field, application of elliptical incision, retroperitoneal blunt dissection for exposure of the ring, reduction of hernial sac with excision of the elliptical fold of skin, and suturing of the two lips of the ring by non-absorbable suture materials, and then the wound is closed in normal manner. The technique induces much straining on the lips of the hernial ring and abdominal muscles especially in large sized herniae, and the possibility of rupture of either the suture material or the hernial ring is high.

d-Surgical reduction and application of mesh

This is the most accurate and proper method for closure of the ring and associated with minimal complications. The surgical field is prepared in the same mentioned manner, elliptical incision is made, retroperitoneal blunt dissection is performed for exposure of the ring, and then a sterile mesh of suitable diameter is fixed to the ring retroperitoneal by non-absorbable suture materials, then the wound is closed in normal manner. This technique causes no straining on the abdominal muscles as there will be no need for collecting the two lips together and the muscular defect is filled with the net.

B-Treatment of strangulated herniae

This type of hernia should be treated as fast as possible, otherwise the animal will die, and in equine it can kill the horse within 12 hours unless surgery is performed. The technique is the same mentioned technique in (c and d) put the ring should be extended to permit proper reduction of the strangulated bowel with minimal traction. The technique is made after incising the peritoneum. If the bowel suffers from necrosis it should be amputated and anastomosed, then the ring is closed by suturing or by using sterile mesh.