Figure 3
Physical examination of the patient revealed poor body condition (grade
3 out of 9 on the scale of the Body Condition Score), and normal body
temperature, heart and respiratory rates; no other abnormalities were
noted. A 10-cm swelling was noted right to the anus; it was soft,
painless and easily reducible, while it increased in size after manual
pressure on both flank regions. Rectal palpation revealed no
abnormalities; in contrast, palpation at the site of the hernia allowed
identifying a 4-cm-long defect opening on the left side, with no
protruding viscera, and a 6-cm-long opening on the right side, between
the levator ani, the coccygeus muscles, the internal obturator and the
external anal sphincter muscles. Blood test were also carried out but
did not show any alteration except for creatine kinase (CK) which was
705 IU/L (reference range 90-270 IU/L) and aspartate aminotransferase
(AST) which was 531 IU/L (reference range 60-280 IU/L). Ultrasonographic
evaluation was carried out using an Esaote MyLabTMAlpha device with both
3.5 Mhz and 7.5 Mhz probes. Ultrasonography showed diffuse
hyperechogenic muscle fibres and hyperechogenic foci within the pelvic
diaphragm muscles on both sides of the pelvic diaphgram; these were
fibres likely due to several muscular microcalcifications, possibly
linked to repeated stress. Multiple traumas could have been directly
related to the muscle weakness of the area. In addition, using the
convex ultrasound probe on the left side, a hyperechogenic structure,
probably corresponding to a bowel loop segment with hypoechoic content,
was identified. Due to the topography of the hernia, the large or the
small colon were probably involved; however, it was not possible to
determine which of the two.It was less probable that the large colon was
involved as it is found in the abdominal cavity. Nevertheless, during
pelvic flexure impaction, this portion tends to move towards the pelvic
area. At this point, based on history, clinical signs, results of
palpation and ultrasonography, the swelling was recorded as a bilateral
perineal hernia.
Surgical procedure: The animal fasted for 12 hours with free
access to water.
The surgery was performed with the animal in a standing position.
Patient preparation started with a pre-wash of the perineal area. The
mare was then sedated with an intravenous injection of detomidine (10
microg/kg bwt) followed by morphine (0.1 mg/kg bwt) and then by a
constant rate infusion (CRI) of detomidine (8 microg/kg/h bwt) which was
administered for additional analgesia. Caudal epidural anaesthesia was
then carried out by preparing the area corresponding to coccygeal
vertebrae C1-C2, followed by subcutaneous infiltration of local
anaesthetic (1 ml Lidocaine). Subsequently, the epidural anaesthesia was
completed with morphine (0.1 mg/kg) and Lidocaine HCl 2% (0.15 mg/kg
bwt). The anus was closed using a purse-string suture after placing a
gauze plug to prevent contamination. The surgical region was then
prepared with Povidone-iodine antiseptic solution. The operation site
was draped with sterile towels (Figure 4a). The surgeon opted for a
standing appositional herniorrhaphy procedure without using any muscle
transposition. The hernia was bilateral, and the surgeon started from
the right side of the perineal area. A dorso-ventral 12 cm linear skin
incision was made over the hernia (Figure 4b). Blunt dissection of the
skin and the underlying fascia was carried out (Figure 4c). In this
case, the hemostasis was carried out using EnsealĀ® - Ethicon forceps
(Figure 4d). The muscles were identified and gently separated from each
other. The levator ani muscle appeared very thin and hypotrophic (Figure
4e). The hernia breach was located between the coccygeus the levator
ani, the internal obturator and the external anal sphincter muscles
(Figure 4f). The pelvic diaphragm muscles were reinforced using a 2 USP
multifilament adsorbable suture which involved the coccygeus, remnants
of the levator ani and the external anal sphincter muscles which were
then anchored to the sacrotuberosus ligament and the periosteum of the
ischium (Figure 4g,h,i). The subcutaneous tissue was sutured with the
same suture material using a simple continuous suture pattern. The skin
was closed using a 1 USP monofilament nylon suture with a series of
horizontal mattress sutures (Figure 4j). The surgeon then repeated the
same surgical technique on the opposite side. With the aim of avoiding
the inclusion of any abdominal organ in the suture, the surgeon placed
his hand in the rectum to check, and no abnormalities were observed