Muscle biopsy is performed to confirm the diagnosis of muscle disease. A small piece of skeletal muscle is surgically removed and appropriately processed and observed under the microscope. The following factors require careful consideration prior to performing a muscle biopsy: (a) Patient selection is important to ensure that correct information can be obtained. Genetic analysis or other tests may be required for diagnostic confirmation. (b) Selection of the appropriate muscle is essential for accurate diagnosis. Therefore, it is recommended that a muscle showing a moderate degree of weakness be biopsied. (c) Studying the specimen must be planned and carefully prepared based on the suspected diagnoses. It is not sufficient to study only wax-embedded muscle tissue. A portion of the specimen must be frozen and cut using the cryostat for histochemical and immunohistological analyses.
Appropriate processing of a portion of the tissue for electron microscopy is required for evaluation of specific muscle disorders. Furthermore, genetic studies require a small piece of the frozen specimen. It is necessary to obtain written informed consent from the patient or family members prior to performing these procedures and studies.