Wintrobe's Clinical Hematology 14e SC

Chapter 1: Examination of the Blood and Bone Marrow 9

needle into the bone marrow cavity should be sensed as a slight give or

increase in the speed of needle advancement. The needle obturator is

removed, and the needle is attached to a 10- or 20-mL syringe. Aspiration

of the marrow is achieved by rapid suctioning with the syringe so that 0.2

to 2.0 mL of bloody fluid is obtained. Aspiration may cause a very brief,

sharp pain. If no pain is noted and no marrow is obtained, the needle may

be rotated and suction applied again. If no marrow is obtained, relocation to another sampling site may be required. 108,111

The aspirated material is given to a technical assistant, who makes

smears of the material ( Figure 1.5 ) and assesses the quality of the

material by noting the presence of marrow spicules. The smears must

be made quickly to avoid clotting in a manner similar to that described

for blood smears using either coverslips or slides to spread the marrow

(Figure 1.3). After smears are made, the aspirate may be allowed to clot

to form a histologic clot section for processing. In some cases, where

immediate slide preparation is not available, the bone marrow may be

aspirated into a tube containing a small amount of anticoagulant to impede

clotting. The aspirate may later be filtered and submitted for histologic

FIGURE 1.4 Jamshidi bone marrow aspiration and biopsy needle. This type of hollow needle with a beveled tip (A) is satisfactory for percutaneous biopsy

processing into a particle clot section. EDTA is the best anticoagulant

to use because it introduces the least amount of morphologic artifact to the specimen. 111 If additional material is needed for flow cytometry,

of the bone marrow. The needle is inserted with the obturator (B) in place. The

biopsy is expressed from the needle using the stylet (C).

cytogenetics, culture, or other special studies, additional aspirations

may be performed by withdrawing the needle and repositioning it in

prevents plugging of the needle before aspiration, and a stylet that may

a new site and drawing marrow into appropriate tubes. Morphologic

be used to express the bone marrow biopsy sample ( Figure 1.4 ). Some

examination requires the best sample, and the aspirations for ancillary

models, primarily used for sternal bone marrow aspiration procedures,

studies should be performed subsequent to the initial aspiration. Occa-

have adjustable guards that limit the extent of needle penetration and reduce morbidity. 109 Most bone marrow needles are disposed of after one

sionally, a portion of an anticoagulated marrow aspirate is spun down

to obtain a buffy coat, thereby concentrating the cellular elements. In

use, and specific longer needles that may be used for obese patients and

some instances, no marrow can be aspirated (dry tap). In these cases,

mechanical drills to aid in bone penetration are available commercially.

it is essential to make smears from material at the tip of the needle and

In most cases, marrow aspiration and biopsy may be carried out with

also to make touch preparations from the biopsy, as outlined below, to allow cytologic examination of the bone marrow elements. 108,111

little risk of patient discomfort, provided adequate local anesthesia is used. Apprehensive patients may be sedated before the procedure. 110 The

The bone marrow core biopsy ( Figure 1.6 ) may be performed using

procedure is performed under sterile conditions. The skin at the site of the

the same skin incision if the aspirate has been performed in the iliac

biopsy is shaved, if necessary, and cleaned with a disinfectant solution.

crest area. A separate biopsy needle that is slightly larger than the nee-

Laboratory Hematology

The skin, subcutaneous tissue, and periosteum in the area of the biopsy

dle used for aspiration may be used, or the same needle that was used

are anesthetized with a local anesthetic, such as 1% lidocaine, using a

for the bone marrow aspiration may be reused. Care must be taken to

25-Gauge needle. Care must be taken to fully anesthetize the periosteum,

reposition the needle biopsy site away from the area where the aspiration

where most of the bone pain fibers are located. After the anesthetic has

was performed to avoid collection of a specimen with extensive artifact induced by the aspiration procedure. 108,112 The use of a biopsy needle

taken effect, a small cut is made in the skin overlying the biopsy site, and

the marrow aspiration needle is inserted through the skin, subcutaneous

may require more pressure to enter the bone because of the larger bore

tissues, and bone cortex with a slight rotating motion. Entrance of the

size. Once the needle is in place in the bone, the stylet may be inserted

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B

A

FIGURE 1.5 Bone marrow aspirate smear stained with Wright-Giemsa stain. The bone marrow aspirate shows a central spicule with dispersion of hematopoietic precursor cells around the spicule. The preparation allows for optimal evaluation of cytologic features of the bone marrow precursor cells. Panel A (low power)

demonstrating distribution of hematopoietic cells near the darkly staining bone marrow spicule in a bone marrow aspirate. Panel B (high power) demonstrating

cytologic features of bone marrow aspirate hematopoietic cells.

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