Treatment of refractory anosmia with topical platelet rich plasma

Introduction: We assess the role of topical platelet-rich plasma (PRP) in the management of anosmic patients;aim to understand the mechanism of action of topical PRP in the olfactory groove;and differentiate and analyze objective vs subjective improvement in patients receiving topical PRP for anosmia. Anosmia affects up to 20% of the general population, has significant negative impact on quality of life, and has been associated with increased mortality. Further, an estimated 30% to 75% of patients who contract COVID-19 develop anosmia or hyposmia. Despite the commonality and adverse impact of this disorder, there are very few effective treatment options. This abstract/ manuscript presents encouraging, late-breaking data showing that topical PRP placed in the olfactory groove may show some efficacy in managing persistent, long-standing anosmia. Methods: Ten patients with persistent anosmia for at least 6 months were included in this pilot study. All 10 patients had failed previous medical management and olfactory training. An absorbable sponge was soaked in PRP and placed in the patient's olfactory groove on one side in a single-blinded and randomized fashion. The other side received an absorbable sponge soaked in saline. The patient was subsequently seen at 4-week intervals for an additional 2 months, with this procedure repeated at each interval. The same side of the nose was treated with PRP at each encounter and was randomized only at the beginning of the trial. At each interval, a Brief Smell Identification Test (B-SIT) was performed on each nostril independently. Results: Nine patients completed 3 treatment sessions, and 1 patient was lost to follow-up after two treatments. The average overall presenting B-SIT score was 3.5 ± 1.76 (scores <4 are considered anosmic);3.9 ± 2.02 in the treatment nostril and 3.1 ± 1.37 in the control nostril. B-SIT scores improved after each subsequent visit, regardless of the nostril side treated. After completion of the 3 treatments, or at the time of exiting the study, the average overall B-SIT score improved to 4.5 ± 1.92;4.6 ± 1.81 in the treatment nostril and 4.4 ± 2.12 in the control nostril. All patients reported subjective improvement in their sense of smell. Conclusion: Topical PRP placed in the olfactory groove appears to show some efficacy in managing persistent, longstanding anosmia.