34th Annual Scientific Meeting proceedings

Inguinal hernias are a well-recognized  condition in colts, characterized by the protrusion of abdominal organs—typically small intestines—through the vaginal ring into the vaginal process. In adult horses, these are usually acquired hernias, often strangulated, requiring urgent surgical intervention.

In foals, three clinical presentations are distinguished: congenital non-strangulated inguinal hernias, ruptured inguinal hernias, and inguinal ruptures. The vast majority are congenital and non-strangulated. Affected foals present with unilateral or bilateral scrotal swelling but are otherwise clinically healthy. The vaginal ring is relatively wide, allowing intestinal loops to move freely in and out of the vaginal process without becoming entrapped. These hernias typically resolve spontaneously as the foal matures and the vaginal ring narrows, usually by 6 months of age.

A ruptured inguinal hernia involves a tear in the vaginal tunic, with intestines located subcutaneously. Though rare, immediate surgical correction is mandatory when diagnosed. Inguinal ruptures occur perinatally due to increased intra-abdominal pressure during parturition, causing a tear in the peritoneum and transverse fascia adjacent to the vaginal ring. This allows intestines to herniate subcutaneously, typically resulting in lethargy or colic signs. Progressive subcutaneous displacement of intestinal loops creates marked swelling on the medial thigh, often accompanied by edematous and abraded skin. Prompt recognition, preservation of the skin, and emergency surgical correction are critical.

Treatment of non-strangulated congenital hernias is generally conservative. Owners are advised to manually reduce the hernia daily to monitor progression and detect enlargement or incarceration. Bandaging techniques are usually unnecessary and may cause pressure sores or abrasions. Surgical intervention is indicated in three scenarios: (1) the hernia is very large or is difficult to reduce; (2) the hernia does not resolve spontaneously; or (3) the owner is unwilling or unable to perform daily monitoring. A simple and effective surgical method is castration with ligation of the vaginal tunic. Despite its efficiency and minimal impact on long-term development, this option is infrequently chosen by owners.

When testicles need to be spared, an elegant alternative is laparoscopic closure of the internal inguinal ring under general anesthesia in Trendelenburg position, using classic sutures, barbed sutures, laparoscopic staples, or tacks. Care must be taken to preserve enough space for the spermatic cord to avoid venous congestion or testicular atrophy. Bilateral closure is recommended, even for unilateral hernias, to prevent postoperative contralateral herniation. In heavier or older foals, mechanical failure of sutures, staples, or tacks may occur, leading to recurrence. Sutures likely offer superior tensile strength and lower recurrence risk compared to staples or tacks, although this has not been conclusively demonstrated in foals. In our clinical experience, we advise against using tacks in warmblood foals older than 4–5 months due to increased failure risk.

Another testicle sparing option is open inguinal repair, where the inguinal canal is approached externally and the vaginal tunic is plicated along the spermatic cord over 2–3 cm. This technique has a low recurrence rate, and bilateral repair is again advisable.

Foals with a ruptured inguinal hernia or true inguinal rupture require emergency surgery. A scrotal or inguinal approach provides direct access to the subcutaneous intestines. If reduction via the rent in the vaginal tunic or inguinal soft tissue structures is not possible, a mini-laparotomy may be performed to reposition the intestines into the abdominal cavity. Unilateral castration with ligation of the vaginal tunic and repair of the torn tissues is mandatory, and closure of the external inguinal ring with a few sutures may further reduce the risk of recurrence.