Complications during treatment of traumatic disruption of the suspensory apparatus in Thoroughbred horses.

A total of 19 Thoroughbred horses were treated for traumatic disruption of the suspensory apparatus, using either external support of the injured limb, removal of fractured proximal sesamoid bone fragments, metacarpophalangeal arthrodesis, compression screw fixation of the fractured proximal sesamoid bones, application of a cast-brace attached to a transfixation pin inserted through the third metacarpal bone, or combinations thereof. Major complications during the treatment of traumatic disruption of the suspensory apparatus were infection (9 of 19 horses, 47%), large cast sores (10 of 14 treated horses, 71%), laminitis (7 of 19 horses, 37%), and orthopedic implant failure or loosening (4 of 6 treated horses, 67%), which led to euthanasia in 16 of 18 cases with complete follow-up information. Increased pain and lameness signaled the development of such complications. In 7 of 9 cases with infection confirmed by microbiologic culture, the horse had received surgical treatment; in 6 of those 7 cases, the infection involved the surgical site. Postoperative wound infection developed in 4 of 7 cases when the surgery was performed within 18 days of injury. In 3 cases, septic metacarpophalangeal arthritis developed, but it was unrelated to surgical procedures. Implant failure or loosening and infection led to euthanasia in 5 of 6 horses treated by internal fixation to stabilize the metacarpophalangeal joint. Three of 6 attempts to perform metacarpophalangeal arthrodesis by application of a bone plate to the dorsal aspect of the joint resulted in implant failure after 45 to 101 days. Major complications did not develop in 2 horses that were treated successfully.

Tracheal reconstruction by resection and end-to-end anastomosis in the horse.

A surgical technique for resection of a portion of the trachea followed by end-to-end anastomosis was developed on 4 clinically normal horses. The trachea healed without complications in 3 of the horses in which 3 tracheal cartilages were removed. Five tracheal cartilages were removed from the 4th horse. It had to be euthanatized because of excessive suture line tension and wound disruption, which occurred during recovery from anesthesia. Suture line tension was measured on 3 other clinically normal horses positioned in dorsal recumbency immediately after euthanasia after 3 and 5 tracheal cartilages had been removed and before and after flexion of the neck to 90 degrees. Suture line tension was reduced by approximately 50% when the neck was flexed. Similarly, the force required to appose the cut ends of the trachea was nearly doubled when 5 rather than 3 tracheal cartilages were removed. The surgical technique was performed on 1 horse and 1 pony with partial obstruction of the trachea. In the pony, 5 tracheal cartilages were resected. It was able to return to successful show competition. In the horse, 4 tracheal cartilages were removed. This horse died of complications resulting from bilateral hindlimb myositis, but the tracheal anastomosis was intact, sealed, and healing well.

Mesodiverticular bands as a cause of small intestinal strangulation and volvulus in the horse.

Volvulus of the jejunum and ileum in three horses was associated with intestinal strangulation in a mesenteric rent. The rent was in the jejunal mesentery at its point of attachment with an anomaly that was classified as a mesodiverticular band. The band also was attached to the dorsolateral surface of the jejunum, thus forming one side of a triangular hernial sac that was completed on the other side by the adjacent jejunal mesentery. Incarceration of a loop of small intestine in the hernial sac preceded rupture of the jejunal mesentery and subsequent intestinal strangulation. Surgical correction was successful in two horses and involved resection of the gangrenous intestine, then jejunocecal anastomosis. The third horse was euthanatized when intestinal rupture and peritonitis were found on exploratory laparotomy. Two mesodiverticular bands attached to the distal jejunum were incidental necropsy findings in a fourth horse.

Epiglottic entrapment by arytenoepiglottic folds in the horse.

An abnormality of the epiglottis and arytenoepiglottic folds that caused epiglottic entrapment was diagnosed in 21 horses. Until recently, this entrapment was poorly understood. Definitive diagnosis of epiglottic entrapment can be made only by endoscopic examination of the epiglottis, arytenoepiglottic folds, and soft palate to differentiate the abnormality from dorsal displacement of the soft palate. Dorsal displacement of the soft palate is often associated with entrapped epiglottis. Epiglottic deformity, especially hypoplasia, is often associated with the entrapment. The abnormality was detected in horses 1 to 16 years old. Because of the relatively large number of young animals (11 being less than or equal to 2 years old), a congenital predisposition was suggested. This suggestion was strengthened by the fact that many of the horses had deformities of the epiglottis that were considered congenital. Because some of the horses had trained and raced satisfactorily before signs of upper airway obstruction developed, it was assumed that the abnormality may be a sequel to epiglottic injury.

Fibrous foreign body impaction colic in young horses.

OF 207 horses with colic seen over a 36-month period, 10 were determined to have impaction colic caused by ingestion of synthetic fencing material. In 6 cases, there was history of exposure to rubberized fencing products. All horses affected were less than or equal to 3 years of age, had signs of mild to moderate abdominal pain, and were unresponsive to usual symptomatic therapy. At surgery, each horse was found to have an impaction involving the distal right dorsal colon, transverse colon, or small colon, and in some cases, all 3 bowel segments. In 9 cases, the involved segment of bowel could not be brought out of the abdominal cavity, and in each of these cases, the foreign bodies were removed through one or more enterotomies. Five of the 10 horses survived.