To describe our approach using a 14-gauge disposable core biopsy to collect muscle tissue.
Muscle biopsy is a routinely used for both clinical care and neuromuscular research. Open and modified Bergstrom needle biopsies are traditionally used, but recently we have implemented disposable core needles.
Three staff persons should be available during the biopsy procedure: a licensed, trained medical professional and two trained staff to assist with the procedure and rapidly process the sample. Following informed consent, a time-out procedure is performed. The biopsy site is marked, cleansed with Chloraprep, and then draped in sterile fashion. Using 1% lidocaine, the skin and subcutaneous tissue (1-2 ml) and muscle tissue just proximal to the planned biopsy site (6-8 mL) are anesthetized. Anesthesia is confirmed by testing pain sensation. A small punch incision (~1-2 cm) is made using a #11 scalpel. The 14-gauge coring needle device is passed through the fascia window at a shallow angle (30 degrees or shallower) traveling as parallel as possible with the long axis of the muscle fibers so that the proximal edge of the cutting window is just within the edge of the fascia. Care is taken to keep the cutting window within the belly of the muscle to avoid collection of adipose tissue and deeper neurovascular tissues. A total of 3-5 passes can be made in smaller muscles, such as the tibialis anterior. The incision is closed with steri-strips and then covered with a sterile bandage. Following sampling, each muscle is rapidly processed according to planned analyses. In our experience, typical muscle weights obtained are approximately 15 to 20 milligrams per pass.
Needle muscle biopsy using a 14-gauge soft tissue biopsy needle is an effective way to collect tissue that yields sufficient tissue sampling with minimal tissue damage and discomfort.