Bone marrow aspiration in north Sudan : the procedure , indications and the diagnostic value

Introduction: Bone marrow aspiration (BMA) is a common and useful investigation tool in clinical practice to obtain information about both hematological and non-hematological disorders. The aim of the work was to identify the main indications for BMA in Atbara city, north Sudan and to determine the common diagnoses encountered. Methods: All reports of BMA carried out during a 6-year period from 2009 to 2014, in the Modern Specialized Laboratory (the only site where BMA is conducted in Atbara) were reviewed. The information extracted included the main indications for performing this procedure, age groups involved, and the most common diagnoses established. A specially designed form was used for this purpose and the data were analyzed using SPSS computer program. Results: A total number of 112 cases were subjected to bone marrow aspiration. The most frequent indications were: pancytopenia 43(38.4%), anemia 39 (34.8%), and suspected leukemia 13 (11.6%).In 86(76.8%) cases, BMA provided either the diagnosis or diagnostic clues to the disease process, while 26 (23.2%) of the aspirates revealed a normally functioning marrow. Conclusion: Bone marrow aspiration is an important investigation for establishing the diagnosis in many medical conditions. The most common indication for this procedure in our study was pancytopenia and the most common finding was aplastic


Introduction
Bone marrow aspiration is a useful investigation tool to help diagnose hematological and non-hematological disorders. (1,2)Hematological indications for this procedure include diagnosis, staging and follow-up of anemia, pancytopenia, lymphoproliferative disorders, lymphomas and many other conditions (Table 1). (3)Nonhematological disorders include pyrexia of unknown origin, granulomatous diseases, metastatic tumors and some inborn errors of metabolism.More sophisticated and ancillary techniques in which bone marrow aspiration is used include flow cytometry, genetic and chromosomal studies. (3)The procedure of bone marrow aspiration is cost-effective, technically simple for the experienced and is associated with minimal hazards when precautions are considered. (3)e aimed by this work to describe our experience in Atbara, north Sudan with special emphasis on indications and findings of bone marrow examination.

Material and methods
This was a descriptive retrospective laboratory-based study in which records of all patients underwent bone marrow aspiration in Atbara, during the period from 2009 to 2014 were retrieved and data extracted.The information obtained included the demographic data, the main indications for performing bone marrow examination and the most common diagnoses established.A special form was designed for this purpose in which data was displayed.

The procedure of bone marrow aspiration and examination
In brief, the procedure consists of inserting a special needle into a bone and withdrawing the red marrow by suction or coring out a sample of the marrow to be examined microscopically.The steps of the procedure can be practically divided into:

Pre-aspiration
Revised CBC and indication, check general condition of the patient (including examination of liver, spleen and lymph node groups), take patient consent, and ensure his/her comfort; patient lying of left side flexing right knee joint and extending left leg.Take universal infection precautions.Check that everything is ready and functioning: disinfectants, local anesthesia, well-fitting plastic syringe.Check the most prominent flat bone, the posterior superior iliac crest is most commonly chosen, but the anterior superior iliac crest may be easier in obese individuals or those with sacral edema.

During aspiration
Patient assurance , explain what you are doing to patient, check your assistance preparedness, administer adequate local anesthetic in skin, subcutaneous tissue and periosteum, wait for a few minutes (2-5 is enough) till patients tell you that there is no pain at insertion site.Insert needle with its trochar, remove trochar once inside marrow and aspirate 0.3 -1.0 ml.May need to repeat aspirate if inadequate sample, or no bone fragments seen.Tell patient that you are finished with the aspiration process.

Post aspiration
Assessing adequacy of the sample, make smears for staining and examination, part of the sample may be allowed to clot, preserved in a fixative solution and submitted for histopathology.Portions of the sample may be submitted to the microbiology laboratory for cultures or special stains e.g.ZN.Certain conditions may require other specialized studies such as genetic testing or cell marker studies.Patient care after aspiration: press firmly, then place adhesive plaster to site of needle insertion.Stop and manage bleeding in case it occurs.Reporting should be systematic: start with a comment on cellularity, megakaryoblasts/cytes, RBCs precursors, WBCs precursors, plasma cells, parasites and any other cells.Write your report and suggest further investigations if needed. (3)mplications of BMA Are uncommon and include local pain, bleeding and infection in addition to complications of local anesthesia. (4)ntra-indications of BMA These are relative and not absolute contraindications for BMA: the very ill/terminal patient, infection at site of aspirate (select another site). (4)

Statistical analysis
Data generated were coded, validated and analyzed using Statistical Package for Social Science (SPSS) version 20 (IBM Statistics, USA).Pearson chi squared test was used to test for significance between proportions; p value below 0.05 was considered statistically significant.The main variables analyzed were age, sex, indication of BMA and the final conclusion/diagnosis.

Ethical Approval
An ethical clearance of the research was obtained from the Ethical Committee of the Faculty of Medicine -Nile Valley University.

Results
A total of 112 cases were subjected to bone marrow aspiration in the period from 2009 up to 2014, with an increased frequency in the last two years (Table 2).The male to female ratio was 1:1.The age range was from one to 87 years (mean+ SD=44.0 +22.1).Adults above 45 years were the majority (Table 2).
The most common clinical indications for bone marrow aspiration were pancytopenia 38.4%, anemia 34.8% and suspected leukemia 11.6%.(Table 3).In 86(76.8%)cases BMA provided either the diagnosis or diagnostic clues to the disease process; while 26 (23.2%) of the aspirates revealed a normally functioning marrow.

Discussion
In this study we described, in brief, the basic concepts of bone marrow aspiration, along with our findings of the clinical indications and the final diagnoses in a 6-year period in Atbara city.
One hundred and twelve cases were involved in this study.The range of BMA requests per year was 10 to 28.This number is lesser than the expected to be seen in a population of 135,000 living in Atbara locality.But because BMA service was not available in this city before, the few number of requests is not unexpected, as physicians need time to be aware of the services available upon their request.Even after an initial increase in the rate of annual requests for BMA, there were drops in certain years.This finding may be attributed to the continuous immigration and replacement of physicians in our local community.However, there is noticeable increase in the rate of requests in recent years.Yet, some authors claim that BMA has deteriorated as a diagnostic tool in clinical practice. (5)This might be true in certain settings where other alternative diagnostic procedures exist.However; in most developing countries BMA is still essential and of great importance for establishing the diagnosis of many conditions.
There was no difference between males and females underwent BMA during study period.This can be explained by the fact that pancytopenia, anemia and hematological malignancies have no obvious sex predilection.
The most common age group underwent the procedure were adults above 45 years.This finding points to the age of bone marrow derangements such as myeloproliferative/myelodysplastic syndromes, myelofibrosis and aplastic anemia.
Aplastic anemia was the most common condition encountered.This is similar to that reported from India, (2) but higher than the rate of anemia investigated in Saudi Arabia (8.3%). (6)The high "normally functioning marrow" (23.2%) results issued may be explained by the fact that many anemia's result from other causes rather than a bone marrow problem.Indications for platelet disorders may reflect the situation of infection (a common cause for platelets decrease/increase), or peripheral destruction rather than their synthesis in bone marrow.
The rarity of cases of pyrexia of unknown origin diagnosed in this study may be explained by the fact that, Sudan is a tropical country and the list of differential diagnoses for PUO is long, so that BMA can hardly settle the diagnosis.The role of BMA in settling the diagnosis in PUO is well studied by some authors, (7) as in only 16.5% was BMA diagnostic.
The rate of hematological malignancies was considerable (15.2%).This is lower rate when compared to the study done in Saudi Arabia. (7)he most common hematological malignancy was chronic myelocytic leukemia 8 cases (7.1%) followed by chronic lymphocytic leukemia 5 cases (4.5%), acute myeloblastic leukemia 2 cases (1.8%) and multiple myeloma 2 cases (1.8%)There were 5(4.5%) cases of visceral leishmaniasis (kalazar) encountered in our laboratory.However, all these cases when traced back were found to be from endemic areas of the disease in east, Sudan.
10) Bone marrow aspiration under CT scan has recently been reported and claimed to increase the diagnostic value of the procedure. (11)he need for collaboration between all stakeholders: physicians, hematologists, pathologists, oncologists and technicians are very important in improving the diagnostic yield of bone marrow examination. (12)imitations of our study include the small sample size that may not allow generalization.Despite this limitation, however, this study is novel and is the first of its kind in north Sudan and is anticipated to constitute a database for future studies.
In conclusion, bone marrow aspiration is a useful investigation tool in clinical practice.It is a safe and cost-effective procedure under the hands of the experienced; and is of added value when clinical notes and a peripheral blood films are also obtained.

Table 1 : General indications for and uses of bone marrow aspiration.
* * This list of indications is not exhaustive and some indications are controversial.

Table 2 .
Frequency of sex and age group for patients, and year of bone marrow aspiration.Atbara,

Table 4 .
Frequency of the final diagnosis of bone marrow aspiration in Atbara, Sudan 2009-2014.