Page 2144 - Cote clinical veterinary advisor dogs and cats 4th

Bone Marrow Aspiration and Core Biopsy 1069

• Clippers dominant hand, palpate the joint, move advancing the needle. Stop after the needle
• Antiseptic scrub solution, isopropyl alcohol, slightly distally, and find the flat surface of is partially seated because it will be further
VetBooks.ir • Sterile gloves • Tent the skin, and make a stab incision. • Remove cap and stylet from needle.
advanced through the marrow after the stylet
the humerus.
gauze squares for skin preparation
has been removed.
• Take biopsy needle in dominant hand, and
• #11 scalpel blade
• Bone marrow aspiration and/or biopsy needle
with firm, downward pressure to fill several
(e.g., Jamshidi), typically 15-18 gauge work through subcutaneous tissues until • Advance needle clockwise-counterclockwise
contact is made with underlying bone. This
• 6-10 mL syringe prevents slippage off of the bone. millimeters of the needle with bone marrow.
• Cytology slides (#20-#30): tilt most slides • After the needle has made contact with the The cap can be replaced, or thumb may be
lengthwise to ≈45% angle, frosted end up, bone, the needle should be perpendicular placed over end of the biopsy needle (where
before starting procedure to the surface of the humerus. Rotate the syringe is attached for aspiration).
• Tissue jar and 10% formalin for biopsy needle clockwise-counterclockwise with firm, • When full purchase has been made and
downward pressure, avoiding any extraneous the needle is deeply seated, rotate (slightly
Anticipated Time side-to-side motion. rock) the needle very slightly in the
15-20 minutes • After good purchase into the bone has been same, circular direction to break core of
made, the needle should be able to move the marrow and bone free from underlying Procedures and Techniques
Preparation: Important entire leg without the needle wiggling. attachments.
Checkpoints • After needle is seated into bone, remove • Continue to rotate (slightly rock) needle
CBC should be obtained the same day as the cap and stylet (place them on sterile surface as it is removed from the bone. A plug
BMA/biopsy. for potential further use), attach syringe, of marrow should be seen in biopsy
and aspirate with short, quick pulses of needle.
Possible Complications and pressure. • Insert the stylet retrograde through the needle
Common Errors to Avoid • After blood/marrow is visualized in hub of to dislodge the tissue plug directly into 10%
Aspirate: syringe (typically only 1-3 short aspirates are formalin. The core sample should have visible
• Inadvertent clotting of sample; preventable required), stop aspiration, remove syringe red marrow. If only white is seen, repeat the
by reducing the time between aspiration and from needle, and immediately disperse onto biopsy procedure to avoid a nondiagnostic
smearing to few seconds microscope slides. sample.
Core biopsy: • Individual droplets of blood/marrow are
• Not always required; BMA is less invasive placed near frosted upper end of tilted slides. Postprocedure
and often adequate Excess blood contamination will drain down • Provide analgesia (e.g., tramadol or
• Loss of the sample on withdrawal of biopsy slide. You should be able to see spicules of nonsteroidal antiinflammatory drugs) for
needle. This can be minimized by adequate marrow as small white/cream dots/clumps 1-3 days, as appropriate.
rocking of the biopsy needle when it is fully on the slide. • For animals with severe thrombocytope-
embedded in the marrow to break off the ○ Any remaining sample collected into nia, apply pressure to site until bleeding
deep attachments to the core. the syringe (accidental oversampling) stops.
• Although unlikely, bone fracture is possible. can be placed on additional slides or in
BMA or core: a purple top Vacutainer tube. Spicules Alternatives and Their
• Inadequate or nondiagnostic sample; be sure can be removed later if slides are Relative Merits
there are visible spicules for BMA or visible inadequate. • Sternal BMA using 18-gauge hypodermic
red marrow for the biopsy core • An additional, blank slide is used to smear needle: can be performed on medium or large
• Hematoma formation or bleeding is rare, the samples, being careful not to place too dogs with minimal sedation. Not amenable
even in thrombocytopenic animals. much pressure on the sample during the to biopsy from this site
• Sliding off the bone, causing soft-tissue squash preparation. • Repeated CBC to assess trends in
trauma: prevented with use of anatomic • Blood/marrow clots extremely fast, and cytopenias
landmarks and making good needle-to-bone the entire aspiration-to-slide preparation • Buffy coat examination
contact before advancing needle into bone should be done very quickly to avoid clotted
sample.
Procedure • If the clinician is satisfied with acquired
Humeral approach to BMA: sample, the needle can be removed from
• For a right-handed clinician, patient is the bone. If not, another aspiration can be
placed in left lateral recumbency. The skin attempted.
over the point of the shoulder is clipped and Ilial approach to BMA:
aseptically scrubbed. • Ilial BMA is more suitable for medium and
• Externally rotate the humerus, find the large dogs than for cats or small dogs and
scapulohumeral joint, move finger distally often requires minimal sedation or only local
from the joint, and locate flat surface of analgesia.
the proximal humerus (distal to the greater • Other than positioning and site of sample
tubercle. Local analgesia is infused subcutane- collection, the procedure is exactly as for
ously deep to the periosteum. humeral BMA.
• Brief aseptic scrub is repeated after local • The animal is positioned in sternal
analgesia injection; clinician then puts on recumbency.
sterile gloves. • Palpate for the small, flat portion on the
• Before making stab incision, remove stylet dorsum of the ilial wing; this is the target BONE MARROW ASPIRATION/CORE BIOPSY
from the biopsy needle to ensure that needle for aspiration, with no regard to using the Position for bone marrow aspiration from the proximal
humerus, using a skeleton for demonstration. This right-
is in working order and seal has been broken; right or left side. handed clinician is standing dorsal to the recumbent
replace stylet. Core biopsy, humerus or ilium: animal and is holding the humerus firmly. The needle
• Using nondominant hand, externally rotate • The same procedure as for bone marrow tip is on the distal, lateral surface of the greater
the humerus (can be done by assistant). With aspiration is followed up to the point of tubercle, ready to be advanced.

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