NEFRECTOMY

 

Nefrectomy is surgical procedure where excision of the kidney is preformed. It is indicated in the cases that defy surgical repair, such as:

 

·         Renal neoplasia,

·         Severe trauma (resulting in uncontrollable bleeding or urine leaking),

·         Pyelonephritis (resistant to medical therapy),

·         Hydronephrosis,

·         Ureteral abnormalities (avulsion, stricture, rupture or caliculi)

 

Before nefrectomy, renal function in the opposite kidney should be assessed by determining its glomerular filtration rate (GFR)*.

 

If renal neoplasia is suspected, radiography (thoracic and abdominal) and ultrasonography should be preformed to help rule out metastasis (including to the opposite kidney). To avoid unintentional transaction, the opposite ureter should always be identified. This is particularly critical when removing large neoplasmas.  

*Glomerular filtration rate (GFR) is the volume of fluid filtered from the renal (kidney) glomerular capillaries into the Bowman's capsule per unit time.[1]

 

 

SURGICAL ANATOMY

 

  • The kidneys lies in the retroperioneal space lateral to the aorta and caudal vena cava. They have fibrouse capsule and are held in position by subperitoneal connective tissue.  The cranial pole of the right kidney lies at the level of the 13th rib. In an average sized dog, the cranial pole of the left kidney lies about 5 cm caudal to the upper third of the last rib.

 

 

 

 

 

 

  • The renal artery normally bifurcates into dorsal and ventral branches but variations are common
  •  The ureter begins at the renal pelvis and enters the dorsal surface of the bladder.

 

NOTE: The anatomy of the renal blood vessels is highly variable, so care is needed when ligate these vessels during nefrectomy.

The left ovarian and testicular veins drain into the renal vein so they should not be ligated in intact dogs.

 

 

 

 

 

SURGICAL TECHNIQUES

 

 

 

 

 

 

  • Make ventral midline skin incision begging from xyphoid and extending caudally towards the pubic area. In male dogs extend it to prepucium and curve it to the left or right side and extend to pubic area. After making the incision on the skin blunt dissection is made to reach to the linea alba. The line is easier to find near the umbilicus since it becomes thinner near the pubis. Then make incision with scalpel on linea alba. Using the probe and scalpel expand the incision to the pubis.

  • Female dog
     
    The right kidney can be exposed by elevating the duodenum and displacing the other loops of intestine on the animal’s left side. The left kidney can be exposed by elevating the mesocolon so that the small intestine is retracted to the animal’s right side.

 

  • Grasp the peritoneum over the kidney and incise it. Free the kidney from its sublumbar attachments, using combination of blunt and sharp dissection. Elevate the kidney and retract medially to locate the renal artery and vein on the renal hilus. After identifying renal artery double ligate it with absorbable or nonabsorbable suture close to abdominal aorta. Make sure that all branches have been ligated. Identify the renal vein and ligate it similarly. Left renal vein ligate above the drain of ovarian or testicular vein. Ligate the ureter near the bladder with absorbable material. Use the transfixation ligature to make sure it doesn’t slip off after cutting the vessels and ureter.

 

  • Close abdomen placing interrupted sutures (X suture).  Incorporate full thickness bites of abdominal wall in the sutures if the incision is made through linea alba. If the incision is lateral to linea alba and muscular tissue is exposed (i.e. paramedian incision) close the external rectus sheath without including muscle in sutures. Use the absorbable sutures. Close subcutaneous tissue with absorbable suture placing continuous sutures. For skin use nonabsorbable sutures placing interrupted sutures.

 

 

NOTE: Sutures that are going to be used in this surgery are explained and presented in ’’ SUTURE KNOTS AND PATTERNS ’’

 

 

 

 

 

 

 

 

REFERENCES:

 

  1.  ^ Physiology at MCG 7/7ch04/7ch04p11 - "Glomerular Filtration Rate"
  2. Theresa Welch Fossum; Small Animal Surgery (second edition); 2002 Mosby; Missouri
  3. Stanley  H. Done, Peter C. Goody, Susana A. Evans, Neil C. Stickland; Color atlas of Veterinary; volume 3; The dog and cat; 1996 Mosby, Missouri