Abdominal Hernias and Perinial Hernia in Small Animals

1. HERNIAS IN SMALL
ANIMALS
Bharat Regmi,BVSc & AH
M.V.Sc,Surgery & Radiology(Pursuing)
Agriculture and Forestry
University(AFU),Rampur Chitwan
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2. Abdominal Hernias
1.External abdominal hernias:
defects in the external wall
of the abdomen that allow protrusion of
abdominal contents
2.Internal abdominal hernias: occur
through a ring of tissue confined within
the abdomen or
thorax (e.g., diaphragmatic hernia,
hiatal hernia).
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3. • External abdominal hernias may involve
the abdominal wall anywhere other than
the umbilicus, inguinal ring, femoral
canal,or scrotum. E.g:ventral, prepubic,
subcostal, hypochondral, paracostal, or
lateral
• True hernias :are enclosed in
a peritoneal sac( ring, sac, and contents).
• False hernias: allow protrusion of organs
outside a normal abdominal opening
E.g:Omphaloceles
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4. • Hernias may be direct (through a rent in
the body wall) or indirect (through an
already existing ring, such as the inguinal
ring or umbilical ring).
• Congenital hernias tend to be indirect,
although direct, traumatic hernias may
arise during dystocia or obstetrical
manipulations.
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5. Umbilical Hernias:
• Umbilical hernias vary in size and may
contain only fat or omentum, or in more
severe cases, intestinal loops.
• Many male dogs with umbilical
hernias are cryptorchid.
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6. Types;
• Reducible: can be reduced into the
abdominal cavity
• Irreducible: contents are irreducible due to
Intestinal strangulation or obstruction &
require emergency surgical correction
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7. Diagnosis
• observation of the hernia sac, palpation
• Examination in dorsal recumbency
facilitates reduction of the contents of the
hernia and hernia ring palpation
• Fine needle aspiration in asceptic
condition.
• ultrasonography, and possibly
radiographs.
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8. • Differential diagnoses: abdominal
swellings with abscess,cellulitis,
hematoma or seroma, and neoplasia.
Treatment
Most small, reducible umbilical
hernias in dogs and cats contain only
falciform fat and are of little clinical
significance
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9.  Many umbilical hernias resolve
spontaneously in young animals or are
small and are not corrected until the animal
is neutered. Spontaneous closure may
occur as late as 6 months of age.
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10. The hernial ring is not palpable in some
animals because the ring closes
subsequent to herniation of
falciform fat or omentum.
Occasionally, intestine or other abdominal
structures can be palpated; they generally
can be reduced into the abdominal cavity.
If the umbilical sac is warm or painful
and the contents are irreducible,
Intestinal strangulation or
obstruction should be suspected.
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11. SURGICAL TREATMENT
• Ventral midline approach
• When umbilical hernias are corrected at
ovariohysterectomy, the hernia repair is
completed during routine abdominal
wall closure. The initial skin incision is
extended cranially over the hernia sac.
• Alternatively, an elliptical incision is
made around the base of a large sac to
remove redundant tissue.
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12. • Skin margins are retracted, and the sac is
dissected free.If fat alone is present in the
sac, the neck of the hernia is ligated and
the sac and remaining contents are
excised.
• Small sacs with no internal adhesions can
be inverted into the abdomen.
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13. • Umbilical hernias containing abdominal
organs may require more extensive
surgery. The skin incision is made around
the base of the hernia, leaving enough skin
to close the defect without tension.
• In incarcerated hernias without
strangulation, the hernia sac is dissected
free without damaging the contents.The
hernia ring is enlarged along the linea alba
to release the contents into the
abdomen.Release contents are inspected
for viability.
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14. • Releasing incisions can be made to
reduce tension on the primary suture line,
provided that the rectus muscles and
underlying fascia have adequate strength.
• Incision are made 2 cm away from the
defect through the external rectus
fascia only.
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15. • The fascia is elevated or dissected off the
rectus abdominis muscle and shifted
towards midline, thereby reducing tension
on the primary repair.
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16. • Synthetic mesh(Hernioplasty) must be
used to repair the defect when some
muscle part is lost due to trauma, bite or
due to dehiscence
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17. • Abdominal hernias secondary to bite
wounds usually are contaminated; wound
infection and dehiscence of the skin or
hernial repair (or both) are common.
• No absorbable mesh should not be
placed in these hernias i.e Hernioplasty
, and the wounds should be drained .
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18. • Intestinal strangulation is most likely to
occur when the hernial defect is about the
size of the intestine and the hernial sac is
large.
• If abdominal viscera in the hernia cannot
be reduced, surgery should be
performed as soon as possible.
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19. Other abdominal Hernias
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20. • The abdominal wall is composed of four
muscle layers (the external and internal
abdominal oblique muscles, the rectus
abdominis muscle, and the transversus
abdominis muscle).
• Abdominal hernias may occur at insertions
or attachments of these muscles or
through muscle bellies themselves.
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21. • For most abdominal hernias, perform a
ventral midline abdominal incision to allow
the entire abdomen to be explored.
• Assess the extent of visceral herniation.
Reduce the herniated contents and
amputate or excise necrotic or devitalized
tissue around the hernia.
• Close the muscle layers of
the hernia with simple interrupted or
simple continuous
sutures(Herniorrhaphy).
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22.  If a large area of devitalized tissue is
removed, use synthetic mesh such as
Marlex or Prolene to close the defect.
Cranial pubic ligament (prepubic)
hernias:
 Injuries to the cranial pubic ligament can
be diffcult to repair. If necessary, drill
holes in the pubic bone to anchor the
sutures.
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24. Paracostal hernias:
• Make a midline incision or make
one directly over the hernia.
• Explore the hernia and suture the torn
edges of the transverse, internal, and
external abdominal oblique muscles.
• Incorporate a rib in the suture if muscle
has been avulsed from the costal arch.
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25. Perinial Hernia
• A perineal hernia is a rupture in the pelvic
floor, through which an organ may
protrude into the region between the anus
and the scrotum.
• The pelvic diaphragm consists bilaterally
of levator ani and coccygeus muscles,
which are surrounded by layers of
fascia.
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26. • Failure of the pelvic diaphragm muscles
and fascia may result in caudal
displacement of these organs, resulting in
a perineal hernia.
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27. Predisposing Factors:
 Breed, hormonal imbalance, prostatic
disease, chronic constipation, and
weakness of the pelvic diaphragm due to
chronic straining, Tail amputation(
docking)
 In large studies of companion animals,
97-98% of affected animals were male
dogs and 85-95% of these were intact.
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28. Symptoms:
• constipation and obstipation, tenesmus,
and dyschezia.
• Stranguria and urinary obstruction may
develop secondary to retroflexion of the
bladder and prostate.
• A perineal swelling ventrolateral to the
anus is evident. Herniation may be
bilateral, but two-thirds are unilateral and
>80% of these are on the right side.
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29. Surgical Approach
• A perineal skin incision is made over the
hernia lateral to the anal sphincter and
extending from a point level with the dorsal
border of the anus to a point ventrolateral to
the anus.
• If contents do not remain reduced , a gauze
sponge can be folded into half and then half
again and secured with a Allis tissue
forceps to make a ‘sponge on a stick’.
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30. • The instrument is used to reduce the
contents and keep them in place while the
pertinent structures are identified.
• Suture closure of hernias is usually
performed in an interrupted pattern with 0
or 2-0, synthetic , monofilament or
absorbable suture.
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31. • Surgical correction is always indicated,
and concurrent castration to reduce
recurrence is recommended.
• The prognosis is guarded because of the
high incidence of recurrence (10%–46%)
and postoperative complications such as
infection, rectocutaneous fistula, anal sac
fistula, ischiatic and pudendal nerve
entrapment, and rectal prolaps
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32. References
• Pearson L.K.Hernias.Veterinary Manual.Department of Veterinary Clinical Sciences,Collegeof Veterinary
Medicine,Washington State university
• Slatter D.H .Textbook of Small Animal Surgery .2003, vol. 1.elsevier Health Sciences
• Ronson L.R .Small Animal Surgical Emergencies. Wiley blackwell
• Fossum T.W .Small Animal Surgery, 4th Ed.
• Rubin S.I.Perineal hernia.Veterinary Manual.College of veterinary Medicine,University of Illinois at Urbana-
Champaign
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