Safety of Dry Needling of the Pronator Teres Muscle in Cadavers: A Potential Treatment for Pronator Syndrome.

BACKGROUND: Entrapment of the median nerve at the pronator teres muscle can contribute to symptoms in the forearm and wrist. The pronator teres is also involved in patterns of spasticity observed in people who had suffered a stroke. Research on treatment efficacy with dry needling is scarce. OBJECTIVE: To determine if a solid filiform needle safely penetrates the pronator teres muscle during the clinical application of dry needling. DESIGN: A cadaveric descriptive study. METHODS: Needle insertion of the pronator teres was conducted in ten cryopreserved forearms with a 30 ×0.32 mm filiform needle. With the forearm supinated, the needle was inserted 3 cm distal to the mid-point between the biceps tendon insertion and the medial epicondyle. The needle was advanced in a cranial and medial direction to a depth clinically judged to be in the pronator teres muscle. Safety was assessed by measuring the distance from the needle to the surrounding neurovascular bundles. RESULTS: Accurate needle penetration of the pronator teres was observed in 100% of the specimens (mean needle penetration: 16.7 ± 4.3 mm, 95% confidence interval [CI] 13.6 to 19.7 mm). No neurovascular bundles were pierced in any of the specimen's forearms. The distances from the tip of the needle to the surrounding neurovascular bundles were 16.4 ± 3.9 mm (95% CI 13.6 to 19.2 mm) to the ulnar nerve (A), 9.0 ± 2.2 mm (95% CI 7.3 to 19.5 mm) to the median nerve (B), and 12.8 ± 4.0 mm (95% CI 10.0 to 15.7 mm) to brachial artery (C). CONCLUSIONS: The results from this cadaveric study support the assumption that needling of the pronator teres using described anatomical landmarks can be accurately and safely conducted by an experienced clinician.