Lateral approach to nephrotomy in the management of unilateral renal calculi in a rabbit (Oryctolagus cuniculus).

Case Description: A 5-year-old 2.23-kg (4.91-lb) spayed female Lop rabbit (Oryctolagus cuniculus) was evaluated because of a history of lethargy, polyuria, and polydipsia of 1 month's duration. The referring veterinarian made a presumptive diagnosis of hypercalcemia of unknown etiology on the basis of a plasma total calcium concentration of 14.0 mg/dL.

Clinical Findings: Physical examination findings were unremarkable. Hematologic and plasma biochemical analysis revealed nonregenerative, normocytic, normochromic anemia (PCV, 28%) with heteropenia (23%; 1,334 heterophils/mL) and a total plasma calcium concentration of 16 mg/dL. Radiographic and ultrasonographic examination revealed radiodense and hyperechoic structures in both renal pelves and right unilateral nephrolithiasis.

Treatment And Outcome: Nephrotomy was performed via laparotomy with a right lateral approach. A nephrolith composed of calcium carbonate and carbonate apatite was removed from the right renal pelvis. The rabbit's plasma tested positive for antibodies against Encephalitozoon cuniculi by means of an indirect immunofluorescence assay, and fenbendazole (20 mg/kg [9.1 mg/lb], p.o., q 24 h) was administered for 28 days. Although plasma calcium concentration was not substantially decreased after treatment (values were 14.1 and 15.1 mg/dL 1 week and 3 months after surgery, respectively), the patient did not have clinical signs of hypercalcemia and died of unrelated causes approximately 1 year after surgery.

Clinical Relevance: To the authors' knowledge, this is the first report of a nephrotomy performed in a rabbit via a lateral abdominal approach. This approach allowed easy location of the kidney and also reduced manipulation, thus decreasing the risk of damaging the abdominal viscera and potentially decreasing postoperative pain.