BONE MARROW EXAMINATION

Bone marrow biopsy is an important and frequently performed invasive investigation undertaken to diagnose a variety of haematologic and non-haematologic disease processes and to obtain supportive evidence for the clinical diagnosis of leukemoid reactions and chronic inflammatory disease. Its uses also extend to monitoring bone marrow transplants and both the effects and the effectiveness of chemotherapy and radiation therapy.  NORMALLY IN THIS HOSPITAL, BONE MARROW  ASPIRATION AND BIOPSY IS PERFORMED BY A CONSULTANT HAEMATOLOGIST, OR HEAMATOLOGY REGISTRAR OR EQUIVALENT WITH APPROPRIATE TRAINING.

         1.   Bone marrow biopsy indications include:

Evaluation of pancytopenia 

Evaluation of possible bone marrow infiltration by leukaemia, metastatic tumour, lymphoma, granulomas etc). 

Diagnosis and staging of solid tumours or lymphoma 

Evaluation of selected cases of fever of unknown origin 

Diagnosis of systemic amyloidosis when other methods have failed. 

Suspected cases of myelofibrosis 

Evaluation of myeloproliferative syndromes (polycythemia vera, essential thrombocythemia etc)

 Failed bone marrow aspiration attempts ("dry tap") 

1. In adults the bone marrow biopsy is usually performed on the right or left posterior iliac crests. 
2. Place the patient in a right or left lateral decubitus position with the knee tops drawn up and back comfortably flexed or in a prone position with a pillow beneath the hips.
3. Once the area of the posterior iliac crest is located by palpation, mark the area with thumbnail pressure and prepare the region with alcohol and iodine, and then drape.
4. Infiltrate the skin, subcutaneous tissue and periosteum with a local anaesthetic. Provide ample time for anaesthetic to take effect.
5. Probe the site with a 21 gauge 1 ˝ inch needle to see if the area is adequately anaesthetised and roughly to outline the borders of posterior iliac crest. This also gives an indication as to the depth at which the bone will be struck and desired angulation of the needle.
6. Make a small (3mm) skin incision with a pointed scalpel blade over the marked area.
7. Hold the needle assembly with its handle rested in the palm, middle and third finger over the transverse handle, and the index finger against the shaft of the needle. The application of the index finger over the shaft helps stabilise the needle and permits proper control.
8. With the stilette and handle in place – introduce the needle through the incision and slowly advance it pointing towards the anterior superior iliac spine.
9. It is useful to put one hand over the anterior iliac crest with the middle or index finger on the anterior superior iliac spine. This approach not only helps stabilise the pelvis and patient in general but also help in the guidance of the needle towards the anterior superior iliac spine.
10. When the posterior iliac crest is reached, it is then penetrated by a controlled forward thrust and gentle rotary motions of the needle. Penetration with the stillete in place should be avoided, as it will reduce the length of the marrow core that will be obtained.
11. Once the cortex is penetrated, the needle becomes locked in the cortical bone. The needle is then held in this position with the left hand while the right hand is used to withdraw the stilette and handle.
12. Advance the needle gently with slow, steady and controlled clockwise and counter clockwise rotary motions until an adequate depth is reached.
13. Rotate the needle completely several times along its long axis to sever all the trabecular connections at the base of the marrow core.
14. Withdraw the needle with a straight pull.
15. Once the needle is withdrawn the biopsy specimen is removed with a blunt probe which must be introduced through the distal cutting end of the needle. During the removal of the specimen, hold the needle and probe near their tips as this stabilises the needle and the probe, preventing damage to the cutting end of the needle and helps easy delivery of the marrow core through the proximal end of the needle.
16. After the biopsy procedure, press the edges of the wound together with an adhesive tape. Apply a gauze dressing on the top of the adhesive tape and instruct the patient to lie on his/her back for 10 to 15 minutes, or longer if the patient has a low platelet count.

     5.    Specimen Preparation and Findings

The bone marrow aspirate is immediately examined for visible bone spicules. The presence of these small spicules suggests an adequate specimen. Direct smears of the aspirate fluid are prepared by the technologist at the bedside. These smears consist of marrow particles and free marrow cells spread onto coverslips. This technique helps to preserve the cytologic appearance of individual blood cells. Bone marrow biopsy samples are handled differently. In many institutions, touch preparations are made first, before specimen fixation. The marrow specimen is touched gently to a clean glass side in several places, without smearing. These "touch preps" are allowed to air-dry and subsequently undergo routine staining. This technique also helps preserve cytologic detail. Once the touch preparations are completed, the remainder of the specimen is placed in a fixative such as formaline or Zenker’s solution. The specimen is then processed according to individual laboratory protocol (for example, overnight fixation, decalcification, wash steps, dehydration, and serial sectioning). Routine strains are performed on process specimens. These include hematoxylin and eosin (H & E), Wright-Giemsa stain, and iron stain. Optional studies may be obtained at a physician request such as cytogenitic analysis, flow cytometry, electron microscopy, and amyloid stains. The Haematology Laboratory must be notified in advance for these studies. Bone marrow specimens may also be submitted for microbiological analysis. Cultures may be obtained for aerobic and anaerobic bacterial, fungi (eg, Histoplasma capsulatum), acid-fast bacilli (eg, Mycobacterium tuberculosis or Mycobacterium avium-intracellulare), and viruses (cytomegalovirus). Fixatives should not be added to specimens submitted for culture. Again, it is important to notify the Microbiology Laboratory in advance for these cultures.

The bone marrow aspirate and biopsy are reviewed by a staff pathologist or haematologist. The preliminary report on the bone marrow aspirate may often be available several hours after the procedure, on request. Normal values for bone marrow cell lines in the adult are as follows:

   6.    Complications

Minor complications include local bleeding, haematoma and discomfort at the needle puncture site. Local infection is rarely seen if proper patient aftercare is provided.

Major complications have been reported with sternal biopsy, including fatal puncture of mediasternal structures. Historical reports of fistula formation, osteomylitis and profuse bleeding have been associated with biopsy of what are now considered non-standard sites, such as the tibia. Complications associated with sampling of the iliac crest are however minimal.

   7.    Summary

The Bone Marrow Biopsy Needle is now widely accepted as the device of choice for performing a bone marrow biopsy. Clinical experience has demonstrated and documented their efficacy and lack of complications.

Nonetheless there remain certain limitations to the use of these devices that could possibly be addressed by improvements to existing devices or indeed alternative products;

1. The procedure is operator dependent
2. Failure of sample retention within the needle is a problem that necessitates repeat procedures increasing patient trauma and discomfort
3. Sample quantity is occasionally inadequate and compromises histological evaluation
4. Sample quality is occasionally poor either as a result of over manipulation of the needle and/or as a result of extracting the specimen from the needle.

Bone marrow sampling is now considered a relatively safe but invasive procedure.