Surgery of the kidney Flashcards
What is the arterial and venous blood supply of the kidney?
Renal artery and vein (at renal hilus)
What are the most common nephroliths?
Ca oxalate
What clinical signs are associated with nephroliths?
- Absent or nonexistent
- Depression, anorexia, hematuria, pain
How do you diagnose nephroliths?
Radiographs (Ca oxalate radiopaque)
Ultrasound
What parameters do you use to determine the best management for nephroliths?
- Type of calculi
- Anatomical location
- Clinical effects
When is surgery for nephroliths indicated?
Obstruction
Infection associated with calculi (i.e. pyelonephritis)
What are the treatment options for nephroliths?
Medical management
Nephrolithotomy
Pyelolithotomy
What are the advantages/disadvantages of medical management of nethroliths?
- Advantage–less invasive
- Disadvantages
- Risk of obstruction elsewhere if stones are not broken down small enough
- Can exacerbate stone’s effects if treat for wrong stone type
What are the advantages/disadvantages of nephrolithotomy?
- Advantages
- Relatively simple procedure
- Can close via sutureless closure
- Disadvantages
- Clamp time is only 20 minutes–if clamp longer can cause permanent vasculature damage
- Risk of renal torsion if kidney is not reattached high enough
What are the advantages/disadvantages of pyelolithotomy?
- Advantages
- Doesn’t require occlusion of blood supply
- Doesn’t damage nephrons
- Disadvantages
- Area only seen when both renal pelvis and proximal ureter are dilated
How do you perform a nephrolithotomy?
- Retract mesocolon/mesoduodenum (to prevent excessive hemorrhage)
- Dissect retroperitoneal fat (to isolate vessels–must ID renal vessels and ureter to avoid damage)
- Temporarily occlude blood supply to kidney
- Mobilize kidney, then make sagittal incision until you reach level of renal stone
- Remove stone manually (save to submit for qualitative analysis and culture the renal pelvis–often assoc. w/ infection)
- Flush renal pelvis and ureter with sterilized heparin saline (to wash away any clots)
- Catheterize ureter to ensure patency
- Close
What instruments can you use to occlude the renal vessels for a nephrolithotomy?
- Rumel tourniquet
- Umbilical tape + hemostat
- Bulldog vascular clamp
- Non-traumatic jaws
- Sitiske clamp
- Curved, non-traumatic occlusion
How long can you occlude renal vessels during surgery?
Max of 20 minutes!
What are the closure methods following a nephrolithotomy?
- Sutureless closure
- Most common
- Hold kidney closed for 5 minutes
- Fibrin seal forms
- Suture capsule only (continuous pattern)
- Horizontal mattress (renal cortex)
- Reattach kidney back to where it was to avoid renal torsion
When is a pyelolithotomy indicated?
When proximal ureter and renal pelvis are dilated due to obstruction (when stone is located further down in pelvis area)
What are the advantages of a pyelolithotomy over a nephrolithotomy?
- Prevents destruction of renal tissue–incision is made directly over stone in the renal pelvis
- Does not require occlusion of blood supply
What is the post-operative management of nephrolithotomy?
- Post-op rads to look for calculi
- Monitor PCV
- CVP (hydration)
- Monitor urine output
- Monitor renal enzymes/electrolytes
- Provide diuresis
- Maintains renal perfusion and minimizes clot formation
How can you diagnose renal trauma?
- Diagnosis
- Contrast excretory urography
- Exploratory celiotomy
- Ultrasound
T/F: Hematuria is an indication for renal surgery
FALSE–it is not an indication for surgery
What is the treatment for minor renal trauma?
Conservative treatment
(bruising, subscapular hematoma)
What is the treatment for moderate renal trauma? What are some examples of moderate trauma?
Surgical intervention
Hemostatic agents/partial nephrectomy
Omental patching
Ex: Capsular/parenchymal tears, extravasated urine/blood
What define major renal trauma?
What is the treatment for it?
What should you ALWAYS do first?
- Extensive parenchymal or vascular damage can lead to hemorrhagic shock and death
- If parenchyma is shattered consider partial nephrectomy or nephroureterectomy
- Evaluate contralateral kidney first
What are the indications for performing a nephroureterectomy?
- Severe infection
- Severe trauma
- Massive hemorrhage, severe tearing of renal tissue
- Obstructive calculi with persistent hydronephrosis
- Neoplasia
- Transplant (felines)
What are the indications for a partial nephrectomy?
- Only indicated if patient has severe contralateral renal damage
- Compromised GFR in other kidney
- Trauma/focal hemorrhage/neoplasia
What are the disadvantages of performing a partial nephrectomy?
Higher incidence of post-op hemorrhage
Technically more difficult
What are the clinical signs of hydronephrosis?
- Unilateral
- Abdominal distension
- Palpable mass
- Mass will be large and regular (neoplasia = irregular)
- Bilateral
- Severe azotemia
- Death
How do you diagnose hydronephrosis?
Abdominal rads
Excretory urogram
Ultrasound
How do you manage hydronephrosis? Will renal function return?
- Eliminate cause
- Evaluate function
- < 1 week obstruction–> complete resolution
- > 4 week obstruction–> might regain 25%
- Nephroureterectomy
- Non-functional or severe renal damage
What are the clinical signs of pyelonephritis?
Signs of infection
Often associated with stones
What are the diagnostics of pyelonephritis?
Ascending infection; predisposed by damaged parenchyma
Can evaluate permanent renal damage with renal function tests
How do you manage pyelonephritis?
- Often have to remove stone to rid of infection
- Continue treatment with antibiotics after removal
- Nephroureterectomy
Giant kidney worm: everythang ‘bout it (basics)
- Dioctophyma renale
- Fish or frog consumption
- Destroys renal parenchyma
- Often diagnosed on necropsy
- Nephrectomy or nephrotomy
What is the most common benign kidney tumor in the dog? In the cat?
Renal adenoma (both dogs and cats)
What is the most malignant kidney tumor in the dog? In the cat?
Dog = renal cell carcinoma
Cat = renal lymphoma
How do you manage renal cell carcinomas in dogs?
Nephroureterectomy + chemotherapy
MST = 6.8 mo
How do you manage renal lymphomas in cats?
Chemo therapeutics
(Not commonly a surgical disease unless causing significant obstruction in urinary tract)
What is a nephroblastoma? What kind of patient does it occur in?
Congenital neoplasia–part of the developing kidney
Occurs in younger patients
How do you manage a nephroblastoma?
Remove if possible (treatment of choice in humans is removal); if not, chemotherapy
MST = 6mo
What are the clinical signs of renal neoplasia?
- Signs vary with type, location, and size
- Hematuria
- Abdominal distension
- Anorexia
- Weight loss
- Depression
- Abdominal pain
How do you diagnose renal neoplasia?
- Abdominal palpation
- Abdominal rads
- 81% abdominal mass
- 54% renal mass
-
Ultrasound
- 100% abdominal mass
- 85% kidney mass
- IV urography, CT, MRI
What are the indications for a renal biopsy?
- Suspected neoplasia
- Nephrotic syndrome (PLN)
- Renal cortex disease
- Non-diagnosed ARF
What should you consider before performing a renal biopsy?
If the information gained will outweigh the risks
When should you avoid performing a renal biopsy?
- Avoid if results don’t:
- Alter course of therapy
- Change prognosis with diagnosis (CRF)
- Owner won’t pursue further therapy
- Higher risk of serious complications
What are some complications of performing a renal biopsy?
- Coagulopathies (clotting profiles)
- Hypertension (risk of hemorrhage)
- Severe chronic hydronephrosis (nephroureterectomy)
What sample size is needed for a renal biopsy? What is the common instrument used?
Sample size must be diagnostic (5-6 glomeruli)
Monopty biopsy needle (spring activated)
What are the various techniques for performing a renal biopsy?
- Percutaneous
- Ultrasound-guided (preferred method)
- Keyhole
- Laparoscopic-assisted
- Wedge/incisional
What is the percutaneous renal biopsy technique?
- Small cats/dogs
- Secure kidney against abdominal wall
- Blind technique–doesn’t visualize target lesions
- Risk of hitting vessels
What is the ultrasound-guided renal biopsy technique?
- Preferred method–non-invasive, no surgical approach
- Very diagnostic
- Advance needle into prepared area
- Penetrate capsule
- Can ID target lesions
What is the keyhole renal biopsy technique?
- Modified surgical flank approach
- Isolate kidney in flank area
- Make keyhole incision–>dissect down to renal tissue with hemostats
- Introduce biopsy needle
What is the laparoscopic renal biopsy technique?
- Forceps hold kidney
- Skin incision
- Needle placement through incision (visualize with laparoscope)
What is the wedge/incisional biopsy technique?
- Ventral midline celiotomy
- Occlude renal vessels
- Crescent-shaped sample
- 5-10mm long
- 5mm deep in cortex
- Close with mattress suture
What are the possible complications of a renal biopsy?
-
Severe hemorrhage
- Hypertension
- NSAID w/in 5 days
- Coagulopathy
- Poor technique
- Hematuria (usually resolves in 2-3 days)
- Hydronephrosis (ureteral obstruction from clot)
What are the indications for a feline renal transplant?
- Irreversible ARF
- Decompensated chronic renal failure
- Polycystic disease
What are the special considerations of a feline renal transplant?
- Cost
- Frequent visits
- Immunosuppression
What are the screening parameters for a feline renal transplant?
- CBC, chem profile
- U/A and culture
- Abdominal rads, u/s, echo
- FELV, FIV, toxo
What 4 things will lead to rejection from a feline renal transplant consideration?
- Virus positive
- Cardiac disease
- Neoplasia
- Fractious
What is required of feline renal transplant donors?
- Excellent health
- 1-3 years old
- Similar screening process for acceptors
- Blood type/cross match
What is the prognosis for feline renal transplant patients?
- MST = 613 days
- 23% do not survive discharge
