Stellate Ganglion Block Fails to Improve COVID-Related Smell Distortion: JAMA

A board-certified anesthesiologist and pain medicine expert administered 6 to 8 mL of active mepivacaine, 1%, or saline, 0.9%, by ultrasound-guided injection at the right or left (randomized 1:1) stellate ganglion. 25% difference between subjects in the percentage of respondents who dropped their DisODOR score by 15 points from the baseline was considered as the primary outcome.

32 people were randomly assigned to SGB (median [range] age, 45 [19-64] years; 25 [81%] female) and 16 were assigned to placebo (median [SD] age, 45 [26-64] years; 13 [81%] female) out of the 48 persons examined in the research. Both groups had comparable times after COVID-19 infection (SGB, 35.3 vs. placebo, 30.6 months; MD = -3.1 months; 95% CI, -10.9 to 3.7).

For SGB, the 3-month response rate was 43% (n = 13), while for the placebo, it was 38% (n = 6; difference, −5%; 95% CI, −32% to 33%). There was no difference in the clinical overall perception of improvement across the groups. Overall, in accordance with the results of this research, SGB is not a better therapy for COVID-19-induced parosmia than a placebo, and as such, it should not be suggested.

Source:

Farrell, N. F., Crock, L. W., Islam, A., Adkins, D., Peterson, A. M., Kallogjeri, D., & Piccirillo, J. F. (2025). Stellate ganglion block for the treatment of COVID-19-induced parosmia: A randomized clinical trial. JAMA Otolaryngology-Head & Neck Surgery. https://doi.org/10.1001/jamaoto.2025.1304