Ultrasound imaging and guidance in peripheral nerve entrapment: hydrodissection highlighted.

Ultrasound (US) imaging has become one of the most useful modalities to assess peripheral nerve disorders. Nowadays, it is as important as nerve conduction studies and electromyography for peripheral nerve entrapment. Additionally, US is also helpful in guiding a possible intervention. As peripheral nerves are tiny, palpation-guided injections are really challenging for precisely targeting the nerves. By using US, perineural injections have significantly become safe and effective. Recently, US-guided hydrodissection has emerged as the mainstream for nerve entrapment. Accordingly, this review aims to summarize and update the mechanism and evidence regarding this imperative procedure for neuropathic pain management. Furthermore, the pathogenesis, anatomic features, US findings and histological correlations of nerve entrapment syndromes will also be discussed in this article.