Page 895 - Equine Clinical Medicine, Surgery and Reproduction, 2nd Edition

870 CHAPTER 4

VetBooks.ir suspected diaphragmatic hernia as sudden collapse, repeated coeliotomy and use of chromic gut sutures
to close the abdominal wall.
following the administration of alpha-2 agonists,
is not uncommon. Surgical treatment consists of
Herniation through body-wall defects may result
reduction of the herniated viscera, resection of in simple or strangulated intestinal obstruction.
devitalised intestine and intestinal anastomosis and
repair of the diaphragmatic defect. In horses with Clinical presentation
acute diaphragmatic defects secondary to trauma, Horses with ventral herniation or prepubic tendon
surgery may be delayed if the animal’s condition is rupture display severe ventral abdominal swelling/
stable. Delay allows for the development of fibrosis oedema and are reluctant to walk. They often lie
of the edges of the defect and easier surgical closure. down and are commonly distressed with increased
heart and respiratory rates. Signs of abdominal
Prognosis pain may be present if the herniated contents are
Horses with diaphragmatic hernia have a poor to compromised.
guarded prognosis for survival. Ventral swelling developing over the abdominal
incision site is observed in horses with incisional
ABDOMINAL HERNIA AND herniation. In these horses, a brown serosanguine-
PREPUBIC TENDON RUPTURE ous discharge from the incision and a progressive
increase in drainage of peritoneal fluid are com-
Definition/overview monly observed prior to dehiscence.
Abdominal viscera may herniate through an ana-
tomical opening or a defect in the abdominal wall. Differential diagnosis
Abdominal herniation includes ventral hernias, inci- Ventral herniation should be differentiated from pre-
sional hernias and acquired inguinal/scrotal hernias. pubic tendon rupture because generally the latter is
In pregnant mares, defects in the abdominal wall not correctable surgically. In mares with ventral her-
may result from stretching/tearing of the abdominal niation, the orientation of the pelvis and the mam-
wall muscles (rectus abdominus, oblique abdominal mary gland is normal. In horses with prepubic tendon
and transverse abdominus muscles) or the prepubic rupture, the pelvis rotates cranioventrally as the pre-
tendon (see Figs. 2.44–2.49). pubic tendon tension is lost from the cranial aspect of
the pelvis. Lordosis may also be noticed because the
Aetiology/pathophysiology pelvis and vertebral column cannot maintain normal
Increased intra-abdominal pressure, degenerative alignment. Cranioventral displacement of the udder
changes in the body wall and delayed, or failure of, resulting from the tipping of the pelvis can lead to
linea alba healing are all involved in the aetiology rupture of the blood supply. Blood may be observed
of abdominal-wall rupture in adult horses. Ventral in the milk of mares with prebubic tendon rupture.
hernias and prepubic tendon ruptures usually occur Postoperative wound infection, severe peri-
in pregnant mares and are associated with degenera- incisional oedema, seroma and sinus formation are
tive change in the body wall in old broodmares, twin easily differentiated from incisional hernias, with
gestation, hydroallantois and/or trauma. the abdominal wall being intact on palpation.
Incisional herniation is a complication of ventral
coeliotomy that is reported to occur in 0.7–15% of Diagnosis
horses that undergo this procedure. No breed or sex External palpation and palpation p/r are helpful to
predilection exists. Dehiscence (acute incisional dis- diagnose these conditions. In ventral and incisional
ruption) usually develops within 8 days after surgery. herniation, external palpation of the abdominal wall
Incisional herniation can develop up to 3 months may define the hernia ring and hernia contents.
after ventral coeliotomy. Incisional hernia risk fac- When there is extensive abdominal oedema this
tors include postoperative incisional infection and procedure is difficult. Commonly, mares with a ven-
swelling, postoperative endotoxaemia and pain, tral hernia resent deep palpation of the affected area.