Stellate ganglion block for treating post-COVID-19 parosmia.

Abstract

Post-COVID parosmia may be due to dysautonomia and sympathetic hyperresponsiveness, which can be attenuated by stellate ganglion block (SGB). This study evaluates SGB as a treatment for post-COVID olfactory dysfunction (OD). Retrospective case series with prospective data of patients with post-COVID OD undergoing unilateral (UL) or bilateral (BL) SGB. Patients completed Brief Smell Identification Tests (BSIT) (12 points maximum) and post-procedure surveys including parosmia severity scores on a scale of 1 (absent) to 10 (severe). Scores were compared from before treatment (pre-SGB) to after first (SGB1) or second (SGB2) treatments in overall, UL, and BL cohorts. Forty-seven patients with post-COVID OD underwent SGB, including 23 UL and 24 BL. Twenty patients completed pre- and post-SGB BSITs (eight UL and 12 BL). Twenty-eight patients completed postprocedure surveys (11 UL and 17 BL). There were no differences in BSIT scores from pre-SGB to post-SGB1 or post-SGB2 for the overall (p=0.098), UL (p=0.168), or BL (p=0.230) cohorts. Parosmia severity for the overall cohort improved from pre-SGB (8.82±1.28) to post-SGB1 (6.79±2.38) and post-SGB2 (5.41±2.35), with significant differences from pre-SGB to post-SGB1 (p<0.001) and pre-SGB to post-SGB2 (p<0.001), but not post-SGB1 to post-SGB2 (p=0.130). Number of parosmia triggers decreased for overall (p=0.002), UL (p=0.030) and BL (p=0.024) cohorts. Quality of life (QOL) improved for all cohorts regarding food enjoyment, meal preparation, and socialization (p<0.05). SGB may improve subjective parosmia and QOL for patients with post-COVID OD, however it may not affect odor identification. Further placebo-controlled studies are warranted.