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A second surgery to repair the hernia was performed
10 weeks after the first surgery. This was also considered as an
opportunity to explore the cause of the leucocytosis. During
this surgery, the apex of the caecum and a 15 cm long,
elliptical area of the left ventral colon were found to be
adhered to the abdominal wall in and around the abdominal
hernia ( Fig 3 ). Adhered portions of intestine were resected
and the abdominal wall defect was repaired using a
polypropylene mesh ( Fig 4 ).
Post surgical care was routine, and the WBC values
returned to normal within 10 days of the second surgery and
the hernia repair was successful ( Fig 5 ).
Discussion
The spleen lies deep in the left hypochondriac region
associated with the stomach and regional blood vessels,
nerves and ligaments are situated on the visceral surface. This
attachment includes the nephrosplenic ligament, the
phrenicorenal ligament and the gastrosplenic omentum that
passes to the left part of the greater curvature of the stomach.
Surgical access to the spleen is possible by a left lateral
approach which usually involves resection of the 17th and/or
the 18th rib. Rib resection was not performed in this filly due
to the emergency nature of the case, the possibility of a
diaphragmatic tear and the relative flexibility of the rib cage in
young foals.
Splenectomy in the horse has been shown to compromise
ventricular function during exercise resulting in decreased
cardiac output (Persson et al. 1973a,b; McKeever et al. 1993).
It has also been shown to result in attenuation of PCV increase
and attenuation of systemic and pulmonary hypertension
during maximal exercise (Davis and Manohar 1988). A major
concern when deciding to perform this procedure other than
the surgical difficulty was the potential for the horse to fail to
reach competitive levels of exercise due to the circulatory
effects of a splenectomy but the owner believed that the filly
was worth salvaging to become a broodmare. The filly is now
3-years-old and although she entered training as a 2-year-old
she has not been raced to date.
The leucocytosis that was noted 6 weeks after the first
surgery was a cause of concern as splenectomised human
patients are more prone to overwhelming sepsis in the
months following surgery (Maron and Maloney 1972;
Holdrinet 1988; Dobloug 1990) and although the same
complication has not been reported in splenectomised dogs,
septicaemia was considered a possibility in this case. The
areas of large intestine that had become adhered to the
body wall at the site of the hernia were found to be necrotic
upon removal and were likely the cause of the leucocytosis
given the improvement in the WBC values following the
second surgery.
Causes of splenic rupture in the horse are poorly
documented, but it is reasonable to assume that splenic
rupture could occur from trauma, such as kicks, falls or
collisions. In this case there was no evidence of such trauma
either pre- or intraoperatively. A groom was present in the
paddock with the foal for the 30 min prior to the
development of signs of abdominal pain and no incidence of
trauma was observed in that time. While it is possible that
trauma resulting in splenic tearing could have occurred hours
previously, the authors? opinion is that the filly would not
have survived the resulting haemorrhage. Spontaneous
splenic rupture has been reported to occur in man
iatrogenically, post partum and secondary to neoplasia,
murine typhus, parasitic infections and Dengue fever
(Miranda et al. 2003; Fergie and Purcell 2004; Daybell et al.
2004; Bljaji ? c et al. 2004). Histological examination of a
section of the spleen revealed no abnormalities.
Splenic rupture should be considered as a differential in
any horse demonstrating signs of abdominal pain with
ultrasound or abdominocentesis findings consistent with
abdominal haemorrhage. It should be considered that the
presence of an on-site surgical facility and the time of 20 min
from initial examination to surgery played a part in the
successful outcome of this case. This case demonstrates that
splenectomy in a foal can be performed without rib resection
and that long-term survival of a foal following splenectomy
is possible.
Fig: 4: Mesh in place prior to closure of the abdomen. Fig 5: Splenectomised filly pictured as a yearling.
EQUINE VETERINARY EDUCATION / AE / July 2008
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372