Ch. 20 Biopsy Principles Flashcards
What depth should a cutting needle biopsy device be inserted to?
1.5 cm or greater into the tissue to be sampled so that the entire sample notch is within the tissue
Name three aspiration core needle biopsy varieties
Jamshidi - has an internal bevel that allows for a large sample aquisition
Klatskin - also has an internal bevel
Menghini - suction based approach
Name two cutting core needle biopsy
Tru cut
Franklin-Silverman
What size needle should be used for renal core biopsies?
14 gauge
According to Tobias but not real life, where should biopsy samples be obtained?
At the periphery of the lesion - the junction of the normal and abnormal tissue
What is the theory behind sentinel lymph node sampling?
If metastasis is located within this lymph node, it is more likely to be in other lymph nodes in that lymphocentrum, but if the sentinel lymph node is negative for metastasis, other lymph nodes in that lymphocentrum are also likely negative
What is the most common complication of liver biopsy?
hemorrhage
How many endoscopic samples are recommended for the stomach, small intestines, and large intestines?
6-8 gastric
10-15 small intestines
3-4 large intestines
How often will surgical biopsies yield a final diagnosis for sampling of the GI tract?
94% of cases
When might renal biopsies be indicated?
glomerular disease (like PLN)
acute renal failure unresponsive to medical therapy
**the goal is to obtain CORTICAL tissue
Name some contraindications to renal biopsy
bleeding disorder, severe anemia, uncontrolled hypertension, pyonephrosis or abscess, hydronephrosis
Why do we only want to sample the renal cortex?
Cortical tissue should be sufficient for a diagnosis
sampling the medulla carries a significantly increased risk of hemorrhage (renal vessels increase in size) as well as an increased risk of infarction and fibrosis
wedge biopsies can be performed with an open surgical approach but may require temporary vascular occlusion to the kidney
What is the most common complication of renal biopsy?
hemorrhage
occurs in 10% of dogs and 15% of cats with normal clotting profiles
Other risks include AV fistula formation, cyst formation, infarction, thrombosis, infection, fibrosis, rarely hydronephrosis
How should you obtain a pancreatic biopsy?
right distal limb is recommended location because it is farthest from the pancreatic ducts and duodenal vasculature
use laparoscopic punch biopsy over laparoscopic cup because punch biopsy cuts while cup tears
when using the laparoscopic punch, grasp and hold the tissue for 30 seconds prior to avulsion to aid in hemostasis
Can you use a bipolar vessel sealing device to obtain a lung biopsy?
yes - but for biopsies that are 3 cm or more from the edge of the lung lobe, suture techniques and staplers/ligation devices are recommended because the bipolar vessel sealing device had inconsistent sealing and consistent leakage at lung pressures below normal thresholds
