Nephrotomy in Dogs

Nephrotomy is a highly complex surgical approach used to access the kidneys and renal pelvis. Nephrotomy may be performed as an exploratory surgery, or to remove nephroliths (kidney stones). Certain breeds have an increased risk of developing kidney stones. These include the bichon frise, Lhasa apso, Yorkshire terrier, and miniature schnauzer. Nephrotomy is usually not the treatment of choice for removing nephroliths except in certain cases, particularly those that involve progressive renal dysfunction, hydronephrosis, recurrent infection, or progressive nephrolith enlargement.

The approach to nephrotomy will vary depending on whether or not it is an exploratory or therapeutic measure. The general procedure steps for nephrotomy are outlined below.

1. A blood sample will be taken and analyzed prior to surgery to ensure it is safe to administer general anesthesia.
2. The dog will be anesthetized. Analgesics and anesthesia will be administered intravenously throughout surgery.  The surgeon may choose to acquire blood from a veterinary blood bank in case of hemorrhage.
3. The operative area is shaved, cleaned, and draped.
4. The surgeon will access the affected kidney.
5. Blood supply to the affected kidney will be ligated, usually with bulldog clamps.
6. The surgeon will incise the kidney via the renal capsule, followed by the renal parenchyma. The length of this incision will vary based on the degree of visualization needed. The renal parenchyma may be separated rather than incised, depending on the surgeon’s preferences and expertise.
7. The nephroliths, if present, will then be removed.
8. If it is an exploratory procedure, the surgeon will examine the area thoroughly and identify any lesions or other clinical signs.
9. The renal pelvis is cultured and flushed. A catheter will be placed in the proximal ureter.
10. Both halves of the kidney are restored to normal position, and the incision is sutured.
11. The surgeon may suture one of the poles of the kidney to the surrounding muscle tissue to prevent torsion.
12. The dog may or may not be hospitalized following surgery.

The effectiveness of nephrotomy for removing nephroliths is unclear in veterinary literature. Some sources claim it does not significantly affect renal function, while others cite a high risk of postoperative complication that often results in decreased renal function. Some veterinary surgeons believe nephrotomy should be avoided if possible. The efficacy of this procedure will likely vary based on the health of the dog and the underlying condition. 

Owners should follow all recovery instructions carefully. The surgical site should be checked each day for swelling, drainage, bleeding, and rupture. If this occurs, owners should consult their vet immediately. The dog may need to wear an Elizabethan cone for up to fourteen days until sutures are removed. 

The veterinarian will usually recommend dietary changes to normalize the pH balance of the dog’s urine. Abdominal x-rays and urine samples will be taken every four to six weeks after surgery to ensure the kidney stones do not recur. If the condition recurs, follow-up appointments will take place every three to six months or as recommended by the veterinarian. If nephrotomy is exploratory, the veterinarian will schedule follow-up appointments to administer treatment for the underlying condition.

The cost of nephrotomy will vary based on standards of living and additional costs incurred. The average price of nephrotomy is $3,500.

Because it is a highly complex procedure that requires significant skill and expertise, complications are relatively common with nephrotomy. The complication rate is roughly 23%. Complications of nephrotomy include, but may not be limited to:

• Intraoperative trauma to the renal parenchyma
• Hematoma formation in the renal parenchyma
• Severe hemorrhage
• Decreased glomerular filtration rate
• Renal azotemia: An increase in nitrogen compounds as a result of decreased blood flow to the kidneys.

However, despite the higher risk of postoperative complications, it should be noted that this surgery is usually recommended for animals that would likely experience more detrimental complications from other procedures. The veterinary surgeon will discuss all possible complications of this surgery with the owner before scheduling the surgery.

If both kidneys are affected, the surgeon will not usually perform both nephrotomies at the same time. Two separate surgeries are required, and will be performed six weeks apart. A different treatment method may be recommended for dogs suffering from conditions affecting both the kidneys.

Diets high in protein, phosphorus, and magnesium may cause kidney stones. A diet that is low in these substances can help resolve kidney stones in as little as two weeks. For some breeds, the occurrence of kidney stones correlates with genetics. These dogs should not be bred.