What is involved in a muscle (skeletal muscle) biopsy procedure?

From the Guidelines

A muscle biopsy is a medical procedure that involves removing a small sample of muscle tissue for laboratory examination, typically beginning with local anesthesia and involving either a needle biopsy, open biopsy, or minimally invasive biopsy. The procedure is crucial for diagnosing various muscle disorders, including muscular dystrophy, inflammatory conditions, infections, and metabolic diseases 1.

Procedure Details

The muscle biopsy procedure usually takes 20-30 minutes, with minimal recovery time for needle biopsies and slightly longer for open biopsies 1. Patients may experience mild pain, bruising, or swelling at the biopsy site, which typically resolves within days. The choice of biopsy method depends on the location and complexity of the procedure, as well as the patient's overall health 1.

Diagnostic Value

Muscle biopsies are valuable diagnostic tools, allowing direct examination of muscle tissue structure, protein expression, and cellular abnormalities 1. The biopsy sample is sent to a laboratory where it's examined under a microscope and may undergo specialized testing, such as immunocytochemistry and immunoblotting for dystrophin 1.

Key Considerations

When performing a muscle biopsy, it's essential to choose a weak muscle to maximize the diagnostic yield and reduce sampling error 1. The procedure should be performed by an experienced healthcare professional, and the sample should be interpreted by a skilled pathologist 1.

Outcome

The primary outcome of a muscle biopsy is to provide a definitive diagnosis of the underlying muscle disorder, which is essential for guiding treatment and management decisions 1. By prioritizing the most recent and highest-quality evidence, the muscle biopsy procedure is a critical diagnostic tool for improving patient outcomes and quality of life.

From the Research

Muscle Biopsy Procedure

The muscle biopsy procedure involves several key steps, including:

• Obtaining a muscle specimen through an open or needle technique under local anesthesia 2
• Selecting a muscle that is affected by the disease but not too weak or too atrophic 2
• Immediately freezing or fixing the biopsied muscle to prevent loss of enzymatic reactivity, DNA depletion, or RNA degradation 2
• Processing the specimens for cryostat sections, paraffin sections, and electron microscopy 3
• Performing a battery of stainings, including histological, histochemical, and histoenzymatic stainings, to evaluate fiber atrophy, morphological, and structural changes and metabolic disorders 2

Techniques and Considerations

Different techniques can be used for muscle biopsy, including:

• Open biopsy, which allows for direct visualization of the sampling site but is more invasive 2
• Needle biopsy, which is less invasive but has limitations in terms of sample size and direct visualization of the sampling site 2
• Ultrasound imaging of the muscle, which can be a valuable precursor to ensure diseased tissue is obtained 4
• Orientation of the muscle sample and processing by appropriate histochemical techniques, which are crucial for accurate diagnosis 4

Diagnostic Applications

Muscle biopsy can be used to diagnose a variety of muscle disorders, including:

• Neuromuscular disorders, such as myopathies and muscular dystrophies 2, 5
• Inflammatory myopathies, such as myositis 6
• Mitochondrial disorders, which may require biopsy of the deltoid muscle 2
• Other conditions, such as rhabdomyolysis, myalgia, and hyperCKaemia 5