What is bone marrow?
You won't feel any pain during the procedure
Bone marrow is the spongy tissue present within the larger bones such as the hip bone, sternum, ribs, and thighbone.
The bone marrow contains stem cells also called hematopoietic stem cells (HSCs) that develop into blood cells:
- White blood cells (WBCs): These fight against infection.
- Red blood cells (RBCs): These carry oxygen and nutrients.
- Platelets: These are responsible for blood clotting.
What are stem cells?
Stem cells are specialized cells in the human body that develop into different types of cells that could be of the skin, muscles, or even brain tissues.
Stem cells can be used in the treatment of various medical conditions to replace damaged tissues (stem cell therapy or stem cell transplant). They arise from various sources based on which they are classified into the following:
- Adult stem cells: These are found in few parts of the body such as the bone marrow. They only develop into certain types of cells.
- Embryonic stem cells: These arise from four- to five-day embryos. They can develop into any tissue.
- Induced pluripotent stem cells: These are adult stem cells induced conditions in the laboratory to develop into any tissue.
- Perinatal stem cells: These are stem cells from the cord blood and amniotic fluid.
What is a bone marrow transplant?
A bone marrow transplant is a medical procedure performed when the bone marrow has been damaged or destroyed due to various conditions. This procedure involves replacing damaged stem cells by transplanting healthy stem cells that promote the growth of new marrow and healthy blood cells, thus helping the levels of white blood cells (WBCs), red blood cells (RBCs) and platelets to increase to normal levels.
Bone marrow transplants are of two types:
- Autologous bone marrow transplant: This uses healthy stem cells from the patient’s own body to replace the damaged tissue.
- Allogenic bone marrow transplant: This uses healthy stem cells from a matching donor. There is a risk of stem cell (graft) failure.
Why is a bone marrow transplant done?
A bone marrow transplant may be done to treat malignant (cancer) and nonmalignant diseases. The healthy stem cells replace the diseased cells of the marrow, thus curing the condition.
Some malignant diseases treated using a bone marrow transplant are as follows:
- Chronic myeloid leukemia and acute myeloid leukemia (cancer arising from the myeloid cells in the bone marrow that form blood cells)
- Acute lymphocytic leukemia and acute lymphocytic leukemia (cancer arising from the lymphocyte cells, a type of white blood cells [WBC] present in the bone marrow)
- Hodgkin and non-Hodgkin lymphoma (cancer of the lymphatic system)
- Hairy cell leukemia (cancer of the B-cells, a type of WBC)
- Multiple myeloma (cancer of the plasma cells or B-cells, a type of WBC)
- Some solid tumors (testicular and pediatric tumors)
Some nonmalignant diseases treated using a bone marrow transplant are as follows:
- Inherited blood disorders (e.g., sickle cell anemia and thalassemia)
- Damage due to chemotherapy or radiation
- Hereditary storage diseases (genetic defects)
- Osteopetrosis (a bone disease)
- Selected autoimmune diseases (body has allergy to its own proteins)
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What is the procedure for a bone marrow donor?
A suitable donor is selected based on the donor’s health status and whether matching criteria to the recipient is similar to that of blood donation.
Before the procedure:
The doctor obtains a detailed medical history, performs a physical assessment and advises complete blood and radiological analysis. Consent for the procedure is also taken.
During the procedure:
The bone marrow is taken from the donor under anesthesia (general or local). During the procedure, the patient does not have much pain. A small incision is made, through which a wide bore needle is inserted into the bone marrow and stem cells are collected in syringes. The donor may experience pain after the anesthesia wears off. Painkillers may be needed for next few days.
For the recipient, the procedure is relatively painless because the stem cells are injected through a vein.
The most common site to obtain stem cells is the iliac spine, a projection on the large broad bone forming the upper part of each half of the pelvis/hip (ilium). It is easily accessible and associated with lesser complications. The sternum may be used in some cases.
After the procedure:
Wound dressing would remain for 24-48 hours. Normal activities can be resumed in a day or two. Patients may experience pain, swelling, and bruising that usually resolve in a week. Painkillers and antibiotics may be prescribed.
Donor complications:
Infection, bleeding, damage to the surrounding nerves and blood vessels, and bone fracture.
Transplant of the stem cells to the patient:
The stem cells are injected into the patient’s blood through the vein, after which they enter the bone marrow.