Percutaneous conchotome biopsy of the deltoid and quadricep muscles in the diagnosis of neuromuscular disorders.

Clinical usefulness and safety of percutaneous conchotome biopsy of the deltoid muscle and of the quadriceps muscle was compared in patients suspected to have a neuromuscular disorder. In 121 samples from the quadriceps muscle and in 39 samples from the deltoid muscle, the quantity of muscle fibers was equal and the fraction of biopsies resulting in a specific diagnosis was similar (50% and 56%, respectively). Also, biopsy from the 2 locations resulted in the same distribution of neurogenic, inflammatory, and myopathic disorders. After quadriceps muscle biopsy, 2 patients developed vasovagal syncopes and one patient a local hematoma, whereas no complications occurred in the patients subjected to deltoid muscle biopsy. We conclude that biopsy from the deltoid muscle is clinically as useful and safe as biopsy from the quadriceps muscle.