Bone biopsy

Bone biopsy is a medical procedure during which a small sample of bone tissue is taken and examined for the presence of cancer cells, infections or any other bone disorders. Bone biopsy involves removing the hard outer portion of the bone from the compact tissue, unlike bone marrow biopsy procedure where the innermost sponge-like material containing marrow is removed to assess for abnormalities.

Why is bone biopsy conducted?

Tests like x rays and bone scans may reveal a tumor, but whether it is benign or malignant and if it is malignant, the type of cancer cell is detected accurately by bone biopsy. Bone biopsy determines the presence of benign tumors like Fibroma, Osteoblastoma, Osteoid osteoma and cysts and cancerous tumors like Ewing's sarcoma, Multiple myeloma and Osteosarcoma. Apart from tumors, bone biopsies are also used to identify the bone infections like osteomyelitis and abnormal bone structures that may be causing persistent pain and tenderness.

Types of bone biopsy

Closed biopsy or needle biopsy involves inserting a needle through the skin into the bone to draw a small bone tissue with the needle. Closed biopsy is performed under imaging guidance using a variety of modalities such as fluoroscopy, CT and MRI. Firstly the doctor will choose the bone, mostly the one that is closer to the surface such as hip bone, but biopsy can be performed on any bone. The area is sterilized with antiseptic lotion and local anesthesia is administered. It is important for the patient to remain motionless during the procedure; he may be strapped or belted to restrict movement.

A small incision is made at the site through which the needle is drilled till it finds bone. Needle will be wriggled into the bone to obtain the sample. After the needle is withdrawn, gentle pressure is applied on the site to control the bleeding; finally, the area is cleaned and covered with the bandage. The tissue sample is sent to the laboratory for analysis.

Open biopsy procedure takes place during surgery after administering general anesthesia. Here, the size of the incision is relatively larger as a small piece of bone is removed from the patient's body for further examination.

The patient is required to undergo few blood tests before the procedure to assess the blood clotting and the functioning of kidneys and liver. Medications like blood thinners and anti platelet drugs may need to be stopped temporarily. The site of the biopsy may feel sore and tender for few days and patient may be given pain relievers. If it is a closed biopsy, the patient can return home within an hour or as soon as he starts feeling comfortable. In the case of open biopsy, the patient will regain consciousness after few minutes but may feel drowsy for few hours after the procedure and is retained in the hospital for the whole day. Whether it is needle or open biopsy, patient should keep the area of biopsy bandaged and dry to avoid infections.

Complications arising from bone biopsy are rare, yet patient should be aware of the risks associated with the bone biopsy. Patient may contact skin infection or suffer from bone infection. There is also a risk of needle breaking the bone and causing injury. Hence whenever there is bleeding, redness or oozing of the pus or fever, pain and chills, it should immediately be brought to the doctor's notice.

Bone Marrow Aspiration

Bone marrow refers to the spongy tissue that is found inside the larger bones such as spine, breast bone, hips, ribs, legs and skull. Marrow has two parts – both solid and liquid. If the solid portion of the bone is sampled, it is called biopsy. Aspiration procedure is used to collect the liquid part of the marrow.

Both the procedures show whether the bone marrow is healthy and making normal amounts of blood cells. This procedure is normally used by doctors to diagnose and monitor blood and marrow diseases, including cancer. In bone marrow aspiration, the doctor uses a needle to draw a sample of the fluid portion. For a biopsy, a larger needle is used to take the sample of the solid part.

Most often bone marrow aspiration and bone biopsy is done at once. Together, they make the bone marrow examination. Although they are different procedures, they offer complementary information about bone marrow cells.

Why is it done?

Bone marrow aspiration and biopsy offer detailed information about the condition of the bone marrow and blood cells. In case the blood tests indicate that cell counts are abnormal, and information is not sufficient about a suspected problem, this is done. The doctor may perform bone marrow exam to diagnose a disease condition involving the bone marrow or blood cells:

• To determine a disease progression
  
• To check the iron levels and metabolism and
  
• To monitor treatment of a disease.

Pre bone marrow aspiration procedure

It is imperative to inform the doctor about any medications and supplements the patient is consuming. This can increase the risk of bleeding after a bone marrow aspiration. In case of anxiety or worry, better talk to the health care provider so that a sedative medication could be given before the aspiration in addition to a numbing agent through local anesthesia at the site where the needle is inserted.

Bone marrow aspiration is done in a hospital, a clinic or in a doctor's room. A specialist in blood disorders – a hematologist – or an oncologist, who is a specialist in cancer does the procedure with a nurse and a trained technologist. It usually takes about half an hour for the exam and if any intravenous sedation is given, extra time is taken for pre and post procedure care.

The patient's blood pressure and heart rate are checked. Some form of anesthesia is administered before the bone marrow aspiration as it can be painful. For many, local anesthesia is sufficient. You will be fully awake during the aspiration, but the site is numbed to reduce pain. If you are quite anxious, intravenous IV sedation is given before the marrow procedure.

Bone marrow aspiration procedure

The area for inserting the biopsy needle is marked and cleaned. The bone marrow fluid (aspirate) is usually collected from the top ridge of the back of the hipbone, and if it is done from the breast bone or the front of the hip near the groin. In young children and kids, the sample is taken from the lower leg bone, just below the knee. The patient will be made to lie down on the abdomen or side.

The bone marrow aspiration is usually done before the biopsy. A small incision is made to insert the needle easier. A hollow needle is inserted through the bone and into the bone marrow. Several samples are taken and aspiration takes only a few minutes. While the health care team ensures that sufficient quantity of sample is drawn, sometimes a 'dry tap' may occur, that is fluid cannot be withdrawn. The needle is moved for another attempt.

Post aspiration procedure

After the bone marrow exam, pressure is applied to the where the needle was inserted to stop the bleeding. A smaller bandage is placed on the site. If local anesthesia had been administered the patient is asked to lie back for 10-15 minutes and apply pressure on the biopsy site. In case, IV sedation had been given, you are taken into a recovery area as sedatives may cause impaired judgment, memory lapses or slowed response.

Tenderness may be felt for a week or more after the bone marrow exam, and the doctor administers pain reliever. You need to keep the bandage dry for 24 hours and not shower or bathe, or swim or use the hot tub. It is okay to get the aspiration site wet after 24 hours. In case bleeding soaks through the bandage, or does not stop even with direct pressure, consult the doctor. The doctor also needs to be contacted if there is persistent fever, worsening pain, swelling at the procedure site and increasing redness or drainage at the procedure site. Also it is advised to avoid rigorous activity for a couple of days to minimize bleeding and discomfort.

Results from bone marrow aspiration

The sample is sent to a laboratory for analysis. The results are available in a few days. The pathologist or hematologist evaluates the samples to check the health of the marrow and if it has enough healthy blood cells and also for abnormal cells. The doctor confirms or rules out a diagnosis and how advanced the disease is or if the treatment is working. Sometimes, follow-up tests are done.

Risks of bone marrow examination

This is a safe procedure and complications are rare. But some complications include:

Excessive bleeding which can happen in people with low platelet count.
Infection in those with weakened immune systems.
Discomfort that could be long lasting in the biopsy site.
Heart and lung problems can be caused due to penetration of the breastbone.
Sedation can cause allergic reaction, nausea and irregular heartbeats in some.

Uses of bone marrow exams

These are used for many conditions including:

• Anemia
  
• Bone marrow disorders which include myelodysplastic syndrome and myelofibrosis.
  
• Blood cell conditions such as Leukopenia, leukocytosis, thrombocytopenia, thrombocytosis, pancytopenia and polycythemia – which produce too few or too many of certain types of blood.
  
• Cancers of the bone marrow or of blood including leukemia, lymphomas and multiple myeloma.
  
• Cancers that have spread to other areas including breast.
  
• Hemochromatosis and
  
• Infections.

While problems with bone marrow can create lasting and serious health problems, bone marrow exams, such as aspiration and biopsy are important to help determine the status and extent of problems in the cells to evaluate and determine further treatment and management.

Osteomyelitis

Osteomyelitis is a medical condition that results from bone infection. The bacteria Staphylococcus aureus is usually the cause of Osteomyelitis. Other possible causes for Osteomyelitis are streptococcus and E. coli. Infection is caused either through the bloodstream or direct bone infection through open wounds or fractures. Surgery, fungal infection, injury or boils can be the source for contamination and infection. Typically the infection results in the formation of pus and abscess in the bone. The blood supply to the bone is affected and Osteomyelitis sets in. Osteomyelitis can affect adults and children. While the long bones of the limbs are usually affected in children, the pelvic or back bone of adults is affected. Chronic Osteomyelitis sets in when there is prolonged loss of blood supply to the affected bone tissue. This can happen in diabetics, dialysis patients and those who abuse drugs intravenously. Persons whose spleen has been removed may be at higher risk for Osteomyelitis.

Osteomyelitis can attack more than one bone at a time. Symptoms of Osteomyelitis are localized swelling and redness in the affected bone area. The patient feels ill and nauseous. There might be fever and pain too. In some cases, Osteomyelitis also results in swelling of feet and ankles or lower back pain. The nagging joint pain fails to respond to pain medications and there is intense pain on touching. There is weight loss and severe fatigue. Tests to diagnose this condition include bone scans and MRI of infected bones. Blood tests and cultures can help identify the type of bacterial infection so that the right course of treatment can be adopted. Blood tests will reveal higher ESR and elevated WBC count in those affected by Osteomyelitis. X-rays can reveal the extent of infection in the affected bone. A biopsy of affected bone tissue can also help identify the bacterial infection.

With early diagnosis, this infection can be treated with antibiotics. Often the antibiotics are given intravenously. Treatment for Osteomyelitis involved hospitalization and bed rest. But newer forms of oral antibiotic therapy have been successful in penetrating bone tissue. This has drastically reduced the need for prolonged hospitalization. In chronic cases of Osteomyelitis, surgical removal of dead bone tissue is required. Bone grafting is done to promote growth of new bone tissue. In rare cases, Osteomyelitis can lead to blood poisoning (septicemia) and destruction of the bone.