Muscle/Nerve Biopsy

The Neuromuscular Center at Phoenix Neurological Associates offers state of the art facilities for the performance and processing of muscle and nerve biopsies.

A biopsy is a surgical procedure in which one or more small pieces of muscle or nerve tissue are removed for further microscopic or biochemical examination. The procedure, often used in the diagnosis of a neuromuscular disorder, is considered “minor” surgery and can usually be performed using a local anesthetic. We are able to perform these biopsies in our Neuromuscular Center, so patients do not need to go to a hospital. The procedure takes less than an hour and patients can go home right after the biopsy.

Muscle Biopsy Procedure (24kb PDF)
Nerve Biopsy Procedure (38 kb PDF)
Post Biopsy Instructions (40 kb PDF)

Muscle Biopsy

A doctor is likely to call for a muscle biopsy after looking at preliminary blood tests, performing an electromyogram (EMG) and physical examination, and determining that the patient’s symptoms indicate an underlying neuromuscular disorder. The muscle biopsy can help distinguish between muscular and neurological problems and can help pinpoint the exact neuromuscular disorder present.

The neuromuscular specialist selects a muscle, usually the biceps, triceps, deltoid or quadriceps muscle, that should yield the most information about the disease. Usually, moderately affected muscles are chosen, the weakest muscles may already be too degraded for analysis. The procedure involves a 2-to-3-inch incision, which is then closed with stitches and may feel sore for a few days.

Nerve Biopsy

Most of the time, nerve disorders can be diagnosed without the need for a nerve biopsy. However, a nerve biopsy can be a necessary and valuable test in some patients, such as those suspected of having inflammation of their nerves. As is the case for muscle biopsies, nerve biopsy is an outpatient procedure that can be performed in our Neuromuscular Center.

Analyzing the Sample

All of the biopsies performed in our Neuromuscular Center are processed in our CLIA certified pathology laboratory. This means the samples do not have to be shipped to outside labs. Our highly trained technicians cut them into many thin sections for examination. Using different tests on different sections, we look at the tissue’s overall appearance, chemical activities in the tissue, and the presence or absence of critical proteins. This analysis can yield information about muscle degeneration and regeneration, fiber type abnormalities mitochondrial abnormalities, scar tissue, inflammation and other clues to specific disorders.The information these tests provide helps determine exactly what disease and what form of it the person has.

Finally, a DNA analysis can be performed on a muscle sample to detect a genetic mutation. Although a blood sample is usually adequate for a DNA test, a muscle sample may be needed to test for mitochondrial DNA mutations.

Your doctor may occasionally recommend a new biopsy even though you’ve had one in the past, especially if you’ve been given a tentative diagnosis or now suspect your diagnosis was incorrect. With many new muscle-protein antibodies now available for testing biopsy samples, as well as new understanding of mitochondrial disorders and new DNA tests, a new biopsy may be desirable.

Getting Results

The analysis of a muscle biopsy sample is a very tedious and labor-intensive process in which many sections of the muscle must be cut, many different types of procedures performed, and the results carefully analyzed. Our lab usually performs a few basic histology tests immediately after the biopsy and then, based on these results, determines what further tests should be conducted. The report is usually available within two weeks of the biopsy.