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. 

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)

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

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.

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).