Ultrasound-Guided Perineural Injection at Guyon's Tunnel: An Anatomic Feasibility Study

Compression of the ulnar nerve (UN) at the wrist causes neuropathy in the ulnar tunnel (UT), or Guyon's tunnel. In the absence of trauma and motor syndromes, primarily conservative treatment is considered. As in carpal tunnel syndrome, a perineural injection of corticosteroids may be beneficial. The aim of this study was to investigate the feasibility of ultrasound-guided injections at the UT. We performed ultrasound-guided injections of ink at the UN within the UT in 21 limbs from 11 non-embalmed cadavers. In all cases, we stained the perineural sheath of the superficial branch of the ulnar nerve within the UT. No ink was found inside the nerve or in adjacent structures such as blood vessels and tendons. In conclusion, perineural injection of the UN in the UT seems to be a technically feasible procedure. On the basis of these anatomic data, clinical trials are needed to prove the concept for routine use.