Castration is the most common surgical procedure performed by equine vets. Although the surgery is technically easy to perform, the complication rate associated with it is relatively high with 20–38% of horses experiencing complications. Whilst pre-operative identification of risk factors can help eliminate some, even with appropriate evaluation and proper surgical technique, complications still occur. Therefore, prompt recognition and quick therapy are essential. This may include treatment performed in the field or in some cases at a referral center.Плиты мощения
Although some degree of swelling develops in almost every horse after castration post-operative swelling and oedema of the prepuce and scrotal area are the most common “complications”. Swelling generally peaks 3–4 days after surgery resolving in 10–12 days. Swelling beyond this time especially associated with clinical signs such as a stiff gait, reluctance to move or urinate is abnormal. This may be caused by failure to remove or stretch scrotal skin after castration, or more commonly because of inadequate exercise after castration, allowing incisions to close prematurely and excess fluid to accumulate. Swelling beyond the initial post-operative period can also be suggestive of infection. Swelling not suspected to be infectious is treated by drainage, anti-inflammatory drugs and importantly with daily exercise to prevent closure of incisions. If untreated, excessive swelling can lead to penile paralysis, deeper infection and urination difficulties.
Infection is the second commonest complication at 3–20%. Clinical signs occur anywhere from days to years, and include fever, scrotal/preputial swelling, lameness, and incisional discharge. Use of ligatures around the spermatic cord has been associated with a higher risk. Different forms of post-castration infection exist. Champignon, infection caused by Streptococcus sp., is characterized by a pussy discharge from the spermatic cord stump with excessive granulation tissue. Scirrhous cord refers to chronic infection of the stump, typically with a Staphylococcus sp. In such cases, the incision heals but the infected stump continues to enlarge and abscess with a draining tract eventually developing. This may take months to years. The stump is often palpable as firm tissue in the inguinal area. In some cases, the abscesses involve the entire cord stump, through the inguinal ring into the abdomen. Any horse with a fever and scrotal/preputial swelling after castration should be treated as a post-castration infection until proven otherwise. Early treatment is usually successful, and consists of opening and stretching the incision, lavage, and administration of antimicrobials. The incision may need to be reopened periodically, and exercise should again be instituted to again prevent premature wound closure. Most infections will resolve if treated early. For those that do not resolve or where signs occur months after castration, surgical resection of the infected tissue is often required for resolution. Other cases warranting immediate attention are those with systemic signs of sepsis or endotoxemia (shock) and those where infection with a Clostridial sp. is suspected. Although rare, tetanus and botulism can occur in unvaccinated horses, and wound infections with other Clostridial sp. can cause serious necrotizing cellulitis, myositis, systemic endotoxemia and even death.
Some bleeding is typical for 5 min, however, hemorrhage in the form of a fast drip or a stream beyond 15 min is excessive and should be addressed. The common sources of post-castration hemorrhage are the testicular artery, a scrotal vessel or a vessel within the cremaster muscle. In the acute situation, the horse is sedated and the cord stump inspected. If the stump is the source of hemorrhage, then it is emasculated again, and a transfixation ligature placed. If the stump has retracted then it can be clamped with forceps which are left in place for 24–48 h. If the hemorrhage is from a scrotal vessel, then it is clamped and ligated. If the source cannot be identified, then the scrotal incision is packed with sterile gauze and sutured closed. Referral is considered in cases where the source of hemorrhage cannot be identified, substantial blood loss has occurred, the horse is in shock, or significant intra-abdominal hemorrhage is suspected. These horses often require general anesthesia to identify and eliminate the source of hemorrhage. All horses with post-castration hemorrhage, regardless of source and how quickly it is identified, are at an increased risk for infection and therefore, should receive antimicrobial therapy.
Eventration after castration is thankfully rare, occurring in only 0.2–2.6% of cases, but it most likely to be fatal. Therefore, referral is always recommended where intestine is involved. Horses with omental eventration do not normally require referral and is generally removed by ligation and transection with few complications. Intestinal eventration usually occurs within 4 h of castration. Risk factors include breed (Standardbreds and Draft Horses), pre-existing inguinal hernias and presence of an inguinal hernia as a foal. In these cases, it is recommended that a modified open castration technique with ligature placement is performed. If intestinal eventration does occur, therapy is aimed at keeping exposed bowel safe from damage and further contamination and in preparing the horse for transport for surgery. The bowel is cleaned of all contamination and replaced into the scrotum, which is closed with suture or clamps. If not possible, then a moist towel or drape can be made into a sling and be used to support the bowel during transport. Survival rates after surgery range from 36% to 87%, depending on length of prolapsed bowel, and the need to perform a resection.
Septic peritonitis rarely occurs after castration; however, the vaginal (or scrotal) and peritoneal cavities do communicate, and therefore, the potential for infection to spread from the spermatic cord to the abdomen exists. Clinical signs include fever, depression, dehydration, colic, diarrhea, and anorexia. Horses with septic peritonitis require IV antimicrobials and anti-endotoxic treatments. In severe cases, indwelling abdominal drains may be required to perform daily lavage.
Veterinary caused penile damage is thankfully rare but has been reported usually when vets mistake the penile shaft for a testicle. However, when the penis is partially dissected from surrounding tissue, while searching for an inguinal or small testicle, then resultant inflammation and trauma can lead to swelling and paralysis. In these cases, cold hosing of the penis and scrotum, to reduce swelling, is indicated, and the penis should be replaced into the prepuce and then held in place with a sling until the swelling subsides enough for the penis to retract normally. If the penis is inadvertently transected during the procedure, then the horse should be referred for immediate surgical repair or partial amputation.
A hydrocele is an accumulation of sterile fluid within the scrotal cavity, it is non-painful, and can occur months to years after castration. They generally do not require treatment unless for cosmetic purposes or in rare cases, where the swelling is significanrt enough to cause lameness. Surgical removal under general anesthesia is the treatment of choice, because the swelling will recur after simple drainage alone.
Although castration complications are relatively common, most of these can be resolved quickly with prompt treatment. However, complications with acute, life-threatening potential, such as hemorrhage, eventration, and infection or peritonitis with systemic signs of endotoxemia, are true emergencies. Apparently simple complications may still require surgery at a later stage if the horses do not respond to initial therapy.