Safety Window for the Volar Needle Approach for Examination of the Pronator Quadratus Using Ultrasonography

Dorsal dry needling to the pronator quadratus muscle is a safe and valid technique: A cadaveric study

BACKGROUND

The pronator quadratus (PQ) muscle is an important stabilizer of the distal radio-ulnar joint and its pain referral pattern can mimic median or ulnar neuropathy. Research on treatment safety and efficacy with dry needling is scarce.

OBJECTIVE

To determine if a solid filiform needle accurately and safely penetrates the PQ during simulated clinical application of dry needling.

METHODS

A cadaveric descriptive study was conducted. Needling insertion of PQ was performed in 10 cryopreserved forearms with a 30*0.32 mm solid filiform needle. With the forearm pronated, the needle was inserted 3 cm proximal to the ulnar styloid in an anterior direction toward the muscle. The needle was advanced into the PQ based upon clinician judgment. Safety was assessed by calculating the distance from the needle to the surrounding neurovascular bundles.

RESULTS

Accurate needle penetration of the PQ was observed in 90% of the cadavers (needle penetration: 19.8 ± 4.0 mm, 95%CI 17.0 to 22.6 mm). No neurovascular bundle was pierced during needling in any specimen forearms. The distance from the tip of the needle was 15.1 ± 4.8 mm (95%CI 11.7 to 18.5 mm) to the ulnar nerve, 15.6 ± 7.6 mm (95%CI 10.0 to 21 mm) to the ulnar artery, 11.2 ± 3.3 mm (95%CI 8.8 to 13.6 mm) to the median nerve, and 4.9 ± 1.4 mm (95%CI 3.9 to 5.9 mm) to the anterior interosseous neurovascular bundle.

CONCLUSION

The results from this cadaveric study support the assumption that needling of the PQ by the dorsal aspect of the forearm can be accurately and safely conducted by an experienced clinician. Studies investigating the clinical safety and effectiveness of this interventions are needed.

A cadaveric study for the volar needle approach to the pronator quadratus using the palmaris longus tendon landmark

INTRODUCTION

Our aim in this work was to determine the safety and accuracy of the volar approach to the pronator quadratus (PQ) through cadaver dissection.

METHODS

Twenty upper limbs from 10 fresh cadavers were investigated. At the level 3 cm proximal to the ulnar styloid process (USP), a needle was inserted just medial to the palmaris longus (PL) tendon. Distances of the median nerve (MN) and ulnar artery (UA) from the needle insertion point (IP) were measured using ultrasonography and cadaver dissection.

RESULTS

The PQ was located at a depth of 10.8-19.9 mm from the skin and had a median thickness of 9.1 mm, measured 3 cm proximal to the USP. The median distances of the MN and UA from the IP were 7.6 and 13.4 mm, respectively.

DISCUSSION

A needle insertion for the volar approach to the PQ was safe at 3 cm proximal to the USP, just medial to the PL tendon.