Bilateral ureteral tears in a foal

Surgery of the Equine Urinary Tract

Urinary surgery in the horse may be challenging. More straightforward procedures, such as urinary bladder or urachal defects, do not usually require specialized equipment or imaging, although laboratory work is helpful. Congenital or acquired conditions of the ureters or kidneys may necessitate advanced diagnostic work-ups including advanced imaging /or and minimally invasive procedures. Some surgery of the lower urinary tract is done in the sedated, standing adult horse. Surgery involving the kidney typically requires general anesthesia. Laparoscopy and associated tools are frequently used. Although many of the surgical procedures discussed are quite involved, they are becoming more commonplace.

[Uroperitoneum in neonatal foals - a review of the literature]

Uroperitoneum is a typical disease in newborn foals. An accumulation of urine develops in the abdominal cavity in consequence to a congenital or acquired leakage in the urinary tract. Colts are more frequently affected than fillies. The most common cause of uroperitoneum is a rupture of the dorsal urinary bladder wall. The urinary bladder is affected in 73.1 %, the urachus in 21.6 % and the ureter in 5.2 % of cases. Typical clinical signs occur 2-5 days postpartum, and encompass reduced general condition, abdominal distention, mild colic symptoms and unphysiologic micturition. Ultrasound examination in conjunction with abdominocentesis is considered as the gold standard of diagnostics. Typical laboratory findings are azotemia, metabolic acidosis as well as electrolyte imbalances, particularly hyperkalemia, hyponatriemia and hypochloridemia. Surgical treatment is the only reasonable therapy. Preoperative metabolic disorders and electrolyte abnormalities should be corrected prior to surgery. Especially hyperkalemia leads to a high potential for complications during general anesthesia. Following effective perioperative stabilization, the presence of a defect in the bladder wall or the urachus carries a good prognosis. In total, 63.6 % of the affected foals are healed. Most common complication is a recurrence of uroperitoneum caused by disruption of the suture line or an incomplete closure of the defect.

Sonographic diagnosis of a presumed ureteral tear in a horse

A 14-year-old thoroughbred gelding was presented for the evaluation of acute abdominal pain. Rectally, there was a soft fluctuant painful swelling dorsal to the bladder and to the right of the midline. The creatinine concentration of the peritoneal fluid was 15 mg/dl. Transrectal ultrasonographic examination of the urinary tract revealed a large collection of fluid dissecting from the pelvic portion of the right ureter ventrally through the right side of the bladder wall and into the retroperitoneal space, and a thickened right ureter and bladder wall at the level of the trigone. Cystoscopically there was moderate hemorrhage within the wall of the bladder. Ultrasonography revealed air within the retroperitoneal fluid collection after ureteral catheterization, confirming the preliminary diagnosis of a tear in the right ureter. The gelding was treated medically. After 48 h of hospitalization, nuclear scintigraphy revealed normal clearance from both kidneys and no apparent leakage from the right ureter. The ureteral tear and urinoma were monitored using transrectal ultrasound until resolution. The horse was successfully returned to racing. This case establishes the value of diagngstic ultrasound in the diagnosis and monitoring of a traumatic ureteral tear in a horse.

Surgical management of a ureteral defect with ureterorrhaphy and of ureteritis with ureteroneocystostomy in a foal

A 2-day-old male foal developed uroperitoneum. Initial exploration of the abdomen via ventral midline celiotomy failed to localize the source of uroperitoneum. Bilateral nephropyelocentesis and antegrade urography were performed, and a defect in the right ureter and stenosis of the left ureter were identified. With the foal in dorsal recumbency in the Trendelenburg position, ureterorrhaphy was performed on the right ureter. After ureterorrhaphy, a ureteral catheter was maintained as a stent. The stenotic left ureter was transected, and ureteroneocystostomy was performed using a drop-in mucosal apposition technique. The ureteral catheter was removed 26 days after surgery. Histopathologic findings suggested that ureteritis of unknown origin was a possible initiating factor for stenosis of the left ureter. The drop-in technique for ureteroneocystostomy may be used successfully for ureteral transposition in horses. Ureterorrhaphy combined with the use of a ureteral stent may be used to repair ureteral defects in foals.