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What is a transthoracic needle biopsy (TNB)?
A transthoracic needle biopsy (TNB) removes a piece of lung tissue for examination and to diagnose lung conditions such as lung cancer.
A transthoracic needle biopsy (TNB) is a method used by radiologists to remove a piece of lung tissue for examination. It involves inserting a long needle through the patient’s chest wall (thorax).
TNB is also called a closed, transthoracic, or percutaneous biopsy. This procedure can be performed on an outpatient basis or during the patient’s hospital stay.
Why is a transthoracic needle biopsy (TNB) performed?
Most often, a transthoracic needle biopsy (TNB) is performed to rule out cancer. It is usually performed after the doctor detects an abnormality on chest X-rays or a computed tomography (CT) scan. Other reasons are
- To diagnose lung infection
- To determine the cause of fluid collection in the lungs
- To determine if the lung mass is benign (noncancerous) or malignant (cancerous)
When is a transthoracic biopsy avoided?
A transthoracic needle biopsy (TNB) is avoided if the patient has the following conditions:
- Bleeding disorder
- Severe bullous emphysema (enlarged alveoli that occur with emphysema)
- Hydatid cyst (fluid-filled sacs caused by parasitic infestation in the lungs)
- Pulmonary hypertension (high blood pressure in the lung arteries)
- Severe hypoxia (low oxygen level in blood)
- Recurrent cough
How is a transthoracic needle biopsy (TNB) performed?
Before the procedure
- The patient is advised not to eat anything for 6-12 hours before the test.
- The doctor will ask the patient to discontinue medications, such as aspirin, ibuprofen or blood thinners (warfarin), for a certain number of days before the procedure.
- Before a needle biopsy of the lungs, a chest X-ray or computed tomography (CT) scan may be performed to locate the exact spot.
During the procedure
- The doctor may give the patient a sedative to make them comfortable.
- The patient leans forward or lies down on their back on the bed.
- The doctor may inject a local anesthetic into the chest wall.
- The doctor makes a small incision on the chest.
- Next, the doctor inserts the biopsy needle, attached to a syringe, into the chest. During this procedure, the doctor looks at images displayed by the computed tomography (CT) scan or special X-ray (fluoroscopy) as the needle moves forward inside the chest toward the suspicious area in the lungs.
- Once the needle reaches the lungs, a small sample of the lungs is drawn into the syringe. The patient may feel a short quick pain or mild discomfort. They will be asked to hold their breath at this time.
- The needle is removed gently, and pressure is applied on the incision wound to stop the bleeding followed by bandaging the wound.
- The procedure usually takes 30-60 minutes.
After the procedure
- If the patient remains stable for 30 minutes, a chest X-ray is taken after the biopsy.
- The biopsy sample is sent to the lab for examination, which usually takes a few days.
- If the chest X-ray does not show a complication known as pneumothorax—collection of air between the lung and chest wall—the patient can begin to eat and move around the hospital.
- The chest X-ray is repeated after three hours to exclude a delayed pneumothorax. If the procedure has been performed on an outpatient basis, the patient can be discharged home on the same day.
- If the patient develops pneumothorax during a transthoracic needle biopsy (TNB), they will be observed for several hours. Sometimes, a chest tube needs to be inserted to allow the draining of air from the chest.
What are the complications of a transthoracic needle biopsy (TNB)?
A computed tomography (CT)-guided transthoracic needle biopsy (TNB) is generally a safe procedure. Complications are observed more in patients aged 60-69 years, smokers and those with chronic obstructive pulmonary disease (COPD).
The possible complications of TNB are
- pneumothorax,
- bleeding of wound or the lungs,
- hemoptysis (coughing of blood),
- hemothorax (leaking of blood in the space between the lungs and chest wall) and
- air embolism (one or more bubbles of air that block a blood vessel).