In the head and neck area, this can be accomplished by blocking the cervical sympathetic stellate ganglion. A stellate ganglion block can be both diagnostic and therapeutic for SMP.
Stellate ganglion block (SGB) is used for the treatment of many medical conditions including complex regional pain syndrome and peripheral vascular disease. Historically, the anesthetic has been injected at the C6 or C7 vertebral level with the Chassignac’s tubercle, the cricoid cartilage, and the carotid artery serving as the anatomic landmarks to the procedure.
The therapeutic effects of SGB are due to the block in neural connections in its region of innervation, the improvement in the blood supply of the region, the reduction of adrenal hormones plasma concentration. It is typically used for pain located in the head, neck, chest or arm that is caused by: Sympathetically maintained pain (reflex sympathetic dystrophy) Causalgia (nerve injury) Herpes zoster (shingles).
Some patients report pain relief immediately after the injection, but the pain may return a few hours later as the local anesthetic wears off. Other patients have longer-term relief that outlasts the duration of the local anesthetic and helps them to reduce their medication use and increase their participation in physical therapy.
Piraccini E, Munakomi S, Chang KV. Stellate Ganglion Blocks. [Updated 2021 Aug 9]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2021 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK507798/
Datta, R., Agrawal, J., Sharma, A., Rathore, V. S., & Datta, S. (2017). A study of the efficacy of stellate ganglion blocks in complex regional pain syndromes of the upper body. Journal of anaesthesiology, clinical pharmacology, 33(4), 534–540. https://doi.org/10.4103/joacp.JOACP_326_16