Definition and Overview
Percutaneous needle muscle biopsy is an outpatient diagnostic procedure that removes a small sample of tissue for laboratory testing. It is performed on patients who are suspected of having muscle problems caused by a disease or infection. In the past, the procedure was performed as open surgery. Although the technique allows doctors to obtain a large biopsy sample, it is highly invasive and performed under general anaesthesia, which places the patient at risk of common surgical procedures. Due to the significant advancements in diagnostic techniques, muscle biopsy is now commonly performed percutaneously using a needle that is inserted through the skin.
Who Should Undergo and Expected Results
Percutaneous needle muscle biopsy is performed to diagnose infections that affect the muscles, neuromuscular disorders, and other abnormalities that affect the muscle tissue. Patients who should undergo the procedure are those who are suspected of having:
- Amyotrophic lateral sclerosis (ALS) – Also referred to as Lou Gehrig’s disease, ALS is a rapidly progressive neurological disease that attacks the nerve cells that control voluntary muscles.
- Polymyositis – A chronic inflammatory disease of the muscle that causes symmetrical muscle weakness.
- Muscular dystrophy (MD) – A group of diseases that causes progressive loss of muscle mass leading to an increasing level of disability.
- Duchenne muscular dystrophy (DMD) – Recognised as the most common type of muscular dystrophy, it is a genetic disorder caused by the mutation of dystrophin, a structural protein in muscle.
- Trichinosis – A type of infection caused by roundworm Trichinella spiralis. Its symptoms include muscle pain, abdominal cramps, diarrhoea, and fever.
- Myasthenia gravis (MG) – A complex autoimmune disorder that causes problems with the nerves affecting the voluntary muscles of the eyes, throat, mouth, and limbs.
- Toxoplasmosis – An infection caused by a parasite causing damage to the central nervous system, especially in infants.
Percutaneous needle muscle biopsy provides accurate diagnosis especially in cases where the patient presents with nonspecific symptoms or when imaging studies and laboratory tests are inconclusive. Biopsy findings help doctors rule out certain conditions and initiate a treatment plan.
How is the Procedure Performed?
Before the procedure, diagnostic tests, including blood tests and physical examination, are performed to ensure that the patient is in good health. To minimise potential risks and complications, patients are advised to notify their doctors if they have a history of bleeding disorder, allergic reactions to certain medications and anaesthetic agents, and if they are taking medications including herbal supplements.
To start, the doctor will select the muscle that is not too weak or atrophic to avoid getting biopsy sample from an end-stage muscle where loss of myofibres is severe. Such muscles cannot provide information on what caused the problem being diagnosed.
The patient is then sedated and local anaesthetic is injected to the target site before the biopsy needle is inserted into the skin and then into the muscle where the sample is taken. The biopsy needle is then removed and the opening in the skin is closed using adhesive strips or stitches, if necessary. If stitches are used, they will be removed during a follow-up office visit.
Possible Risks and Complications
As for the possible risks and complications, percutaneous needle muscle biopsy is associated with:
- Pain, bruising, and discomfort at the biopsy site
- Prolonged bleeding and infection of the biopsy site
Allergic reaction to the anaesthetic used
Omura MC, Motamedi K, UyBico S, Nelson SD, Seeger LL. Revisiting CT-guided percutaneous core needle biopsy of musculoskeletal lesions: contributors to biopsy success. AJR Am J Roentgenol. 2011 Aug. 197(2):457-61.
Rimondi E, Rossi G, Bartalena T, Ciminari R, Alberghini M, Ruggieri P, et al. Percutaneous CT-guided biopsy of the musculoskeletal system: results of 2027 cases. Eur J Radiol. 2011 Jan. 77(1):34-42.