Stellate ganglion block

A stellate ganglion block or stellate ganglion blockade or SGB or cervicothoracic ganglion block is a nerve block injection in the lower neck/upper back area, either on the left or the right side.

Theory
The stellate ganglion, also known as the cervicothoracic ganglion, is present in 80% of the population, and forms by a natural fusion between the inferior cervical ganglion and first thoracic ganglion.

A stellate ganglion block was proposed as a treatment for dysautonomia symptoms in Long COVID by Liu and Duricka (2021) based on their treatment of just two patients.

Liu and Duricka proposed that a stellate ganglion block on both sides may cause a "reset" of the sympathetic nervous system (SNS), which they propose could allow it to return to homeostasis, resolving or improving dysautonomia symptoms. Changes to the sympathetic nervous system affect the parasympathetic nervous system (PNS), which is the other key part of the autonomic nervous system. Dysautonomia is a range of conditions involving the failure of parts of the SNS and PNS, and sometimes over or underactivation.

Evidence
Liu and Duricka published a case study of two Long COVID patients, both women in their 40s, who had received stellate ganglion blocks on both left and right sides at their clinic.

Patient self-reports were the only results, there were no medical readings or measures reported:
 * significant improvement in cognitive dysfunction, especially long-term memory recall
 * improvements in fatigue
 * sense of smell and taste returning to normal

Risks and safety

 * Horner's syndrome results from a successful stellate ganglion block, which is expected to resolve after the block wears off.
 * Liu and Duricka's study is a pre-print and not yet peer reviewed, peer review may highlight significant issues or prevent publication.
 * No medium or long term follow-up information is available for the Liu and Duricka study. It is not known how long the beneficial effects may last, and later complications or issues may develop.
 * Potential conflict of interest by Liu and Duricka, who performed the treatments at the pain clinic Liu owns and where Duricka is employed, leading to possible financial gain from future patients
 * No case series or controlled trials in men, different ethnic groups, or with younger or older people, people with ME/CFS, or people with other medical conditions
 * Extremely small case series, which has not been duplicated by other clinicians.
 * No indication of whether the same treatment has resulted in different results in different patients
 * Nerve block risks - these are reasonably well established

Notable studies

 * 2021, Stellate ganglion block reduces symptoms of Long COVID: A case series - (Full text)

Learn more

 * Stellate Ganglion Block - Cedars Sinai Medical Center
 * Neuroanatomy, Stellate Ganglion - StatPearls book