Neuromuscular disease is a very broad term that encompasses many diseases and ailments that impair the functioning of the muscles, either directly, being pathologies of the muscle, or indirectly, being pathologies of nerves or neuromuscular junctions. Neuromuscular diseases are those that affect the muscles and/or their direct nervous system control.
There are multitude of neuromuscular diseases that are exceptionally difficult to diagnose. In some cases, even extensive clinical examination and laboratory workups fail to reveal a diagnosis. In these cases, a nerve and or a muscle biopsy might be required to secure a diagnosis. Once a definitive diagnosis is obtained, the appropriate prognosis and treatments may be provided.
Essentially any nerve or muscle in the body can used for biopsy. The majority of biopsies sample muscles and nerves that are surgically-accessible with a local anesthetic with a minimum of effort. These procedures are almost invariably tolerated quite easily by awake patients.
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. A muscular biopsy will take place in the selected 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.