Needle muscle biopsy: techniques to increase sample sizes, and complications.

Muscle biopsy samples of the vastus lateralis (444) using Bergström needles were obtained under local anesthesia from 43 normal athletes and 17 patients with suspected muscle disease. Five biopsy techniques were used and sample weights were compared. Biopsy during isometric muscle contraction was the most effective technique, yielding a mean sample weight 3.2 times that obtained by simple needle insertion, the least effective method (p less than 0.001). Use of a 5mm rather than 4mm diameter needle raised the mean (+/- 1 SD) sample weight to 35mg (+/- 7.3) from 13.7mg (+/- 5.2) (p less than 0.001), and total yields of 150-200mg were easily obtained by resampling. No difficulties were encountered in the biochemical, histochemical, or immunofluroescent evaluations of these samples. Several subjects were assessed for complications at various times following biopsy. Mild to moderate symptoms, signs, and investigative findings were noted in some subjects within the first few days. Only one person reported subsequent persistent symptoms at the biopsy site-a mild "awareness" during athletic exertion. The higher-yield techniques were generally safe, well tolerated, and provided samples of sufficient size and quality for multiple simultaneous studies. Needle biopsy appears to warrant increased use in physiatric research and clinical practice.