Equipment and reagents
The necessary equipment for obtaining bone marrow
is usually available as a packaged, sterilized set.
Antiseptic—povidone-iodine solution
Local anesthetic—lidocaine hydrochloride
Sterile cotton gauze pads
Sterile syringes and plungers—a 10 ml syringe is
used to administer the anesthetic. A 5 or 10 ml
syringe is used to collect the specimen.
Sterile surgical blade
Disposable needles—25 and 20 gauge needles are
usually used when administering the anesthetic.
Aspiration needle and stylet or biopsy needle, stylet,
and probe
Sterile adhesive bandage or butterfly closure
Procedure
1. Place the patient in the prone position with his or
her head resting on his or her folded arms.
2. Identify by palpation the posterior superior iliac
spine of the iliac crest.
3. Cleanse the skin over the puncture site using the
antiseptic. The remainder of the procedure is
performed using sterilized equipment and sterile
technique.
4. Local anesthesia is achieved by infiltrating the
skin, soft tissue and periosteum at the puncture
site with 2-3 ml of lidocaine hydrochloride. Use
the 25-gauge needle for the skin and the
20-gauge needle for the soft tissue. Wait 4-5
minutes for the full anesthetic effect.
5. If a biopsy is to be obtained, make a 3 mm skin
incision using the surgical blade to allow the
biopsy needle to pass through the skin easily.
6. Insert the needle with stylet in place holding the
needle perpendicular to the plane of the back.
7. Advance the needle through the bony cortex
using firm pressure and an alternating twisting
motion. Penetration into the marrow space is
usually accompanied by a sudden increase in the
ease of advancing the needle.
8. Remove the stylet and attach the specimen
syringe.
9. Aspirate marrow by withdrawing the plunger. If
no marrow enters the specimen syringe, remove
the syringe, replace the stylet and advance the
needle a few millimeters. Again remove the
stylet, attach the specimen syringe, and attempt
the aspiration. If this fails, remove the syringe,
replace the stylet, and withdraw the needle until
the tip is in the subcutaneous tissue. Redirect
the needle into a nearby site.
10. Aspirate about 0.5 ml of marrow. The patient
will usually experience a few seconds of suction
pain during the aspiration.
11. Remove the syringe from the aspirating needle
and hand it to the assistant or technician who
will process the specimen.
12. If only an aspirate is to be obtained, replace the
stylet and withdraw the needle. Apply firm
pressure to the incision site using a sterile gauze
pad.
13. If a biopsy specimen is to be obtained, replace
the stylet, withdraw the needle from the bone,
and reinsert the needle into nearby bone.
14. When the needle is firmly fixed in bone, remove
the stylet and then slowly advance the needle 2-3
cm into the medullary cavity using an alternating
twisting motion.
15. Replace the stylet. The length of the core speci-
men will be shown by the distance the end of the
stylet projects from the needle hub.
16. Break off the specimen by rotating the needle
through several turns in one direction then in the
other or by rocking the needle from side to side.
17. Withdraw the needle and apply firm pressure to
the incision site using a sterile gauze pad.
18. Remove the biopsy specimen by inserting the
probe into the needle from the cutting end and
pushing the core out through the hub. The assis-
tant or technician will process the specimen.
19. Apply a butterfly closure to the skin incision and
cover the site with an adhesive bandage.
20. Examine the incision site periodically for bleed-
ing in patients who are thrombocytopenic.
Specimen Collection Procedures A-6
BONE MARROW: POSTERIOR ILIAC CREST
ASPIRATION AND BIOPSY
