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