Topical Platelet-Rich Plasma: A Novel Delivery Method for an Emerging Treatment of Olfactory Dysfunction

ABSTRACT

Introduction: Olfactory dysfunction (OD) affects more than 3 million US adults. The number of patients with post viral olfactory dysfunction (PVOD) is expected to increase secondary to the worldwide COVID-19 pandemic. Preliminary studies have demonstrated the efficacy of platelet-rich plasma (PRP) in restoration of smell in both animals and humans. To date, human studies have utilized injectable PRP only. We describe our pilot study investigating the use of topical PRP as a novel delivery method for smell restoration and contribute to existing literature demonstrating the promise of PRP as a therapeutic. Method(s) Pilot study from September 2020 to January 2022. Patients >18 years with hyposmia diagnosed via Brief Smell Identification Test (B-SIT) score <8 were included. PRPimpregnated Surgifoam was placed into bilateral olfactory clefts monthly for at least 3 months. Patients completed the B-SIT at baseline and 1 month after each treatment. Result(s) Eight patients underwent at least 3 treatments and completed the B-SIT at month 4. Average age was 56.3 years;mean smell loss duration was 19.3 months. Etiologies included PVOD, post-COVID (5), and idiopathic. Mean change in B-SIT after 3 treatments was +1.06. Of patients, 62.5% had achieved the minimal clinically significant difference of >1 on B-SIT after treatments 2 and 3. Patients with smell loss <12 months demonstrated greater B-SIT scores at 4 months (+1.6 vs +0.2). Two patients achieved B-SIT >8 after 3 treatments. Of patients who have returned thus far for a fourth treatment, 1 additional patient scored >8. Conclusion(s) We present the largest pilot study to date for the use of PRP in treatment of OD and the first study to develop methods for topical delivery in human subjects. Topical PRP may serve as a less invasive, efficacious therapy for patients. Further, randomized control trials are warranted to investigate the required number of topical PRP treatments for smell restoration.