Page 503 - Equine Clinical Medicine, Surgery and Reproduction, 2nd Edition

478 CHAPTER 2

VetBooks.ir anus from damage but leaving a rectovaginal/ves- between 4 and 8 weeks depending on the severity of
the injury. Surgical repair is undertaken once all the
tibular fistula.
First-degree perineal lacerations often heal spon-
taneously with the assistance of daily cleansing and inflammation has resolved and is essential if return
to breeding is required (see Figs. 2.80–2.84).
possibly application of antiseptic creams. Surgical With mares with a foal at foot the surgery is often
repair should be performed within 8–12 hours delayed until after weaning. Pre- and postopera-
of foaling or after a delay of 2–4 days in order to tive measures to improve the success of the surgi-
allow the immediate swelling and inflammation to cal repair are essential and must be carried out with
subside. Many clinicians use a Caslick’s vulvoplasty great care:
(p. 488) type procedure. Re-breeding is usually pos-
sible at the second oestrus unless wound healing is • Preoperatively. Decrease faecal volume and
compromised. loosen their consistency to ease defecation and
Second-degree perineal lacerations generally decrease rectal impaction (i.e. give a laxative
require surgical repair because if the perineal body diet: decrease concentrates; lush green grass;
is damaged significantly, the normal anatomy of the pelleted grass rations; laxatives including
vestibule and vulva may become disrupted. This magnesium sulphate; bran mashes). Withhold all
can lead to anal and dorsal vulvar/vestibular sink- food 24 hours prior to surgery to reduce surgical
ing, pneumovagina and ascending vaginal infection contamination by faeces.
(p. 487). Surgical repair should be undertaken after • Perioperatively. Medications 24 hours prior
all the inflammation and swelling have subsided, to surgery until 5–7 days post surgery should
with many of these mares benefiting from post- include broad-spectrum antibiotics and
foaling systemic antibiotics and NSAID therapy, NSAIDs. Tetanus prophylaxis.
tetanus prophylaxis and daily wound cleaning and
application of antiseptic creams to encourage reso- The surgical repair is undertaken in stocks under
lution of any infection and inflammation prior to standing sedation, preferably with xylazine epidural
repair. Once healthy granulation tissue is present, anaesthesia +/– lidocaine infiltration. There are many
careful and minimal sharp debridement, under local variations in the surgical procedure, which can be
anaesthesia, with anatomical layer repair (especially undertaken in one or two stages, but the basic prin-
the perineal muscles), will ensure a return to normal ciples of all of them should include: the use of strong
function of the vulvar and vestibular seals. absorbable monofilament suture material; minimal
Third-degree lacerations, if presented imme- tension on the suture lines by careful and extensive
diately after foaling (4–6 hours), can be treated by dissection of tissue planes allowing apposition with-
emergency surgical repair. Many cases are, however, out tension; creation of a thick shelf between the rec-
so badly traumatised and contaminated that this is tum and vestibule; and placement of all sutures with
unlikely to be successful or lead to only a partial, good bites of tissue to decrease breakdown of suture
poor-quality repair. Most cases benefit from a delayed lines. The exact surgical procedures are detailed in
surgical repair. Initial treatment is similar to that for the standard surgical texts. In one-stage repairs the
second-degree lacerations, but will be required for vagina, perineal body and rectum are all repaired at
much longer (2–4 weeks). Manual removal of faeces the same time. In a two-stage repair the rectovaginal
every 6–8 hours may also be required in some mares shelf is constructed initially, but the perineal body is
for varying periods depending on the extent and rebuilt at a later stage.
severity of the injury. The removal of all dead and The pre-operative diet and perioperative medica-
extensively damaged tissue by careful sharp debride- tions are continued postoperatively and the external
ment at an early stage will speed up the process of wounds on the perineum are gently cleansed and
secondary intention healing, although it is impor- antiseptic ointment applied daily. The laxative diet is
tant not to be too aggressive. Granulation, epithe- continued for 4 weeks. Monitoring for normal faecal
lialisation and healing of the damaged areas take passage is vital and any straining to pass faeces must