Case Report: Mesh repair of a urinary bladder dorsal wall defect following repeated cystorrhaphy in a warmblood foal.

Mesh repair was successfully used to fix a persistent urinary bladder wall defect in a foal after repeated traditional suturing attempts failed, offering a new method for managing difficult bladder injuries.

Background and Clinical Presentation

• A three-day-old male Warmblood foal was brought in because it could not urinate.
• Initial clinical signs included abdominal swelling and laboratory abnormalities such as elevated potassium (hyperkalemia) and azotemia (high nitrogen waste products in blood).
• Ultrasound showed free fluid in the abdominal cavity, suggesting leakage of urine into the abdomen (uroperitoneum).
• Abdominocentesis (sampling of abdominal fluid) confirmed the presence of urine in the abdomen through a high ratio of creatinine in abdominal fluid compared to blood (>2:1), diagnostic for uroperitoneum.

Initial Treatment and Complications

• The foal underwent surgery to repair a tear in the dorsal wall of the urinary bladder, using sutures (cystorrhaphy).
• Despite initial repair, urine continued to leak along the suture tracts causing recurrent uroperitoneum.
• Computed tomographic urography (advanced imaging to visualize urinary tract) confirmed ongoing leakage two days after surgery.
• A second surgical repair was performed; however, uroperitoneum recurred again four days later.
• During the follow-up surgery, the bladder tissue was found to be inflamed, fragile, and weakened at the site of the tear, increasing the risk that sutures alone would fail.

Use of Mesh Repair

• Given the friability of the bladder tissue, a composite monofilament mesh (Monocryl-Prolene) was used to reinforce the bladder wall defect.
• The mesh acted as a scaffold to support the bladder tissue and prevent excessive distension and further leakage.
• This approach represented an alternative to repeated traditional suture repairs in challenging bladder wall defects.

Outcome and Follow-Up

• The foal was discharged three weeks after admission in good general condition with normal urination and physiological development.
• Telephone follow-up confirmed the foal was gaining weight and urinating normally.
• The foal died suddenly one year later due to urine leakage caused by urolith (bladder stone) formation at the ventral bladder wall.
• At necropsy, the mesh was found well integrated into the dorsal bladder wall, with no evidence of adhesion (undesirable tissue attachments) formation.

Clinical Significance and Recommendations

• This case demonstrates the feasibility and benefit of using mesh reinforcement when bladder tissue is friable, and primary suture repair is unlikely to be successful.
• Mesh repair provided a durable solution for persistent bladder wall defects, preventing ongoing urine leakage and uroperitoneum.
• Veterinarians should consider mesh reinforcement early in cases of bladder injury with poor tissue quality to improve outcomes and reduce the risk of surgical failure.
• Further studies might help establish mesh repair as a standard approach for complicated urinary bladder wall defects in foals and other animals.