1. 2021;24;533-548Ultrasound-Guided Nerve Blocks in the Head and Neck for Chronic Pain Management: The Anatomy, Sonoanatomy, and Procedure
   Narrative Review
   Jinpu Li, MD, and Alexandra Szabova, MD.

BACKGROUND: Ultrasound guided nerve blocks have become a popular tool in the armamentarium for pain physicians because of its advantages over fluoroscopy by offering portable, radiation-free and real-time imaging. But ultrasound guided procedures require training and practice to gain the expertise. There is a scarcity of review articles describing ultrasound guided injections techniques for nerve blocks of the head and neck.

OBJECTIVE: To elucidate the anatomy, sonoanatomy, indications, techniques, side effects and complications for the most frequently utilized nerve blocks of the head and neck in chronic pain management.

STUDY DESIGN: Narrative review.

SETTING: Academic medical center.

METHODS: Literature review of publications in English language of the related topics using Medline (Ovid) search engine.

RESULTS: Deep cervical plexus block, cervical sympathetic ganglion block, trigeminal nerve and pterygopalatine ganglion block at the pterygopalatine fossa, greater occipital nerve block, third occipital nerve and medial branch block, and cervical selective nerve root block are discussed in this paper. The review begins with in depth discussion about the anatomy of the target nerve, followed by reviewing the available literature on the indications for the procedures. Detailed description of the procedure techniques is also presented. The volume and selection of medications is also discussed if there is available research. The review will conclude with summary of side effects, complications and precautions.

LIMITATION: We only review those nerve blocks of the head and neck that would benefit from ultrasound guided injections in chronic pain management. Other nerve blocks such as transnasal sphenopalatine ganglion block, the interscalene brachial plexus block, superficial and intermediate cervical plexus block, anterior suprascapular nerve block, superficial trigeminal nerve block are not discussed due to either that ultrasound guidance is not warranted or they are rarely utilized in chronic pain management. This paper is not a systematic review, thus it might not include all the available evidence. Many of the available evidence is case series and case reports. More randomized control studies are warranted in the future to validate these techniques.

CONCLUSION: Ultrasound guided nerve blocks of the head and neck are useful techniques for pain physicians to learn.

KEY WORDS: Cervical plexus block, cervical ganglion block, pterygopalatine ganglion block, trigeminal nerve block, greater occipital nerve block, medial branch block, selective nerve root block