Latissimus Dorsi Fine Needle Muscle Biopsy A Novel and Efficient Approach to Study Proximal Muscles of Upper Limbs

BACKGROUND: The muscle biopsy based on the Bergstr\uf6m needle has been widely used for more than 40 y for diagnosis and experimental studies on muscle. More recently, thinner needles and tru-cut needles have also been introduced. Such techniques have been largely tested on various muscles, including the quadriceps, with few studies on upper limb muscles like deltoid, and no studies on latissimus dorsi muscle (LDM). In this study, we implemented and validated a protocol to collect samples of LDM for experimental purposes, causing minimal discomfort to volunteers. Two main problems were considered: the anatomical localization of the biopsy site and the selection of an appropriate needle. MATERIAL AND METHODS: A strict protocol of palpatory anatomy was adopted and validated with ultrasonography to localize the biopsy site in LDM in subjects with various degrees of muscle development. A 14 gauge tru-cut needle was selected as the smallest and still effective device for sampling. Biopsy sampling was performed in 18 subjects without any complications, or complains of pain or functional limitations. RESULTS: Approximately 4 mg of tissue were recovered from each introduction of the inner notched cannula of the needle. With three consecutive samplings, an amount of tissue sufficient to prepare proteins for gel electrophoresis and Western blot and to dissect single fiber segment for functional experiments, was obtained. CONCLUSIONS: Taken together, the results suggest that this biopsy technique opens to experimental studies muscles until now never considered accessible