Diagnosis and treatment of inguinal midline abdominal wall herniation of the urinary bladder in three domestic rabbits (Oryctolagus cuniculus)

Inguinal herniation of the urinary bladder through the inguinal rings of domestic rabbits (Oryctolagus cuniculus) has been well-described in veterinary literature due to the inguinal rings remaining open throughout the lifespan of adult males. Midline body wall herniation has also been described in several veterinary species due to a variety of etiologies, including trauma, incisional dehiscence, and congenital anomalies. This phenomenon has not previously been described in rabbits. This case series describes three adult male intact rabbits that presented to three separate institutions with a swelling on ventral midline of unknown etiology. One rabbit had decreased food intake, frequent urination, and urinary incontinence prior to presentation; one rabbit was lethargic and unwilling to move; and one rabbit presented without clinical signs. Herniation of the urinary bladder was diagnosed via imaging in each case and surgical repair was elected. During surgical dissection of the hernial sac, it was discovered one rabbit had a herniated loop of small intestine as well. In each case, the inguinal rings were identified separately, the margins of the body wall defect were excised, and the body wall was reconstructed. This presentation required an altered surgical approach compared to inguinal ring herniorrhaphy procedures that have previously been described in rabbits. One rabbit had worsening of pre-existing azotemia after the procedure. Surgical complications, including recurrence of herniation, were not observed in these three rabbits. Midline body wall herniation of the urinary bladder should be considered as a differential diagnosis in rabbits with caudal abdominal and/or inguinal swelling or clinical signs of urinary disease.