Platelet-rich Plasma in Management of Anosmia (Single Versus Double Injections)

Platelet-Rich Plasma for Treating COVID-19-Related Anosmia, Hyposmia, and Parosmia: A Controlled Longitudinal Study

OBJECTIVE

To investigate the effectiveness of platelet-rich plasma (PRP) injection into the olfactory clefts of coronavirus disease 2019 (COVID-19) patients with persistent anosmia, hyposmia, and parosmia.

STUDY DESIGN

Controlled study.

SETTING

Multicenter study.

METHODS

From March 2022 to July 2024, 514 COVID-19 patients undergoing PRP injection and olfactory training versus olfactory training (controls) for a persistent olfactory dysfunction (OD) were consecutively recruited from two medical centers. Subjects were evaluated from pre- to 3 months post-injection with the olfactory disorder questionnaire (ODQ) and the threshold, discrimination, and identification (TDI) test. Olfactory outcomes were compared between controls and patients considering the type of OD (anosmia, hyposmia, and parosmia).

RESULTS

The PRP group was composed of 416 patients with anosmia (N = 111; 26.7%), hyposmia (N = 160; 38.5%), and parosmia (N = 145; 34.9%). The baseline ODQ of patients with parosmia was significantly higher than those of the other groups (P = .001). The increase in TDI subscores and total score was significantly higher in all PRP subgroups compared to controls (P = 0.001). The ODQ significantly reduced from pre- to post-PRP injection in hyposmia and parosmia groups (P = 0.001). Patients with parosmia showed a significantly greater reduction in ODQ scores compared to the control group. The 3-month TDI score was negatively influenced by the age of patients (rs = -0.263; P = 0.001) and the duration of OD (rs = -0.213; P = .001).

CONCLUSION

Patients with parosmia experienced a stronger impact of OD on quality of life (QoL), and showed greater QoL improvement following PRP injections compared to other groups.

Short-term efficacy of platelet-rich plasma in the treatment of persistent olfactory dysfunction: systematic review and meta-analysis

PURPOSE

To assess the short-term effects of topical platelet-rich plasma (PRP) injection on persistent refractory olfactory dysfunction.

METHODS

A comprehensive literature search of the PubMed, SCOPUS, EMBASE, Web of Science, Google Scholar, and Cochrane databases was conducted for articles up to November 2023. The search focused on studies that compared the amelioration of olfactory dysfunction between a topical PRP treatment cohort and a control group (receiving either placebo or no treatment), along with pre- and post-treatment comparisons. Subgroup analysis of the evaluation of olfactory function was also performed.

RESULTS

The improvement in olfactory scores 1-3 months post-treatment (standardized mean difference = 1.5354 [95% confidence interval: 0.7992; 2.2716], I2 = 83.8%) was greater in the treatment group than in the control group. In the treatment group, PRP increased the threshold, discrimination, and identification (TDI) score for Sniffin' Sticks by > 5.5 (minimum clinically significant difference; mean difference = 6.1789 [3.9788; 8.3789], I2 = 0.0%), indicating clinically significant improvement based on verified examinations. The rate of significant improvement among patients was 0.6683 [0.5833; 0.7436] after treatment. All TDI subdomains were significantly and similarly improved after treatment.

CONCLUSION

This meta-analysis suggests that injection of PRP into the olfactory fissure or surrounding mucosal areas is an effective treatment for persistent refractory olfactory dysfunction in the short term.

Platelet-Rich Plasma (PRP) in the Treatment of Long COVID Olfactory Disorders: A Comprehensive Review

Background: Long COVID has brought numerous challenges to healthcare, with olfactory dysfunction (OD) being a particularly distressing outcome for many patients. The persistent loss of smell significantly diminishes the affected individual's quality of life. Recent attention has been drawn to the potential of platelet-rich plasma (PRP) therapy as a treatment for OD. This comprehensive review aims to evaluate the effectiveness of PRP therapy in ameliorating OD, especially when associated with long-term COVID-19. Methods: We executed a comprehensive search of the literature, encompassing clinical trials and observational studies that utilized PRP in treating OD limited to COVID-19. We retrieved and comprehensively discussed data such as design, participant demographics, and reported outcomes, focusing on the efficacy and safety of PRP therapy for OD in COVID-19 patients. Results: Our comprehensive analysis interestingly found promising perspectives for PRP in OD following COVID-19 infection. The collective data indicate that PRP therapy contributed to a significant improvement in olfactory function after COVID-19 infection. Conclusions: The evidence amassed suggests that PRP is a promising and safe therapeutic option for OD, including cases attributable to Long COVID-19. The observed uniform enhancement of olfactory function in patients receiving PRP highlights the necessity for well-designed, controlled trials. Such studies would help to refine treatment protocols and more definitively ascertain the efficacy of PRP in a broader, more varied patient cohort.

Efficacy of Platelet-Rich Plasma in the Treatment of Persistent Olfactory Impairment After COVID-19: A Systematic Review and Meta-Analysis

Background and Objectives

This study aimed to evaluate the impact of topical platelet-rich plasma (PRP) injection on persistent refractory olfactory dysfunction after COVID-19 infection.

Methods

A systematic review was conducted, focusing on studies that compared the efficacy of topical PRP treatment with a control group (receiving either placebo or no treatment) in ameliorating olfactory dysfunction. Pre- and post-treatment comparisons were evaluated, along with a subgroup analysis of olfactory function evaluation.

Results

The analysis revealed a significant improvement in olfactory scores between 1 to 3 months post-treatment (standardized mean difference=1.4376; 95% confidence interval [CI]=0.5934-2.2818; I2=84.1%) in the treatment group compared to the control group. Moreover, a notable disparity was observed between the two groups in the incidence of substantial recovery from anosmia or hyposmia (odds ratio=8.6639; 95% CI=2.9752-25.2292; I2=0.0%). PRP treatment led to a clinically significant increase in the threshold, discrimination, and identification (TDI) score for the Sniffin' Sticks test by >5.5 (minimum clinically significant difference; mean difference, 6.3494; 95% CI=4.0605-8.6384; I2=0.0%), as confirmed by verified examinations. The odds ratio for significant improvement among patients after treatment was determined to be 0.7654 (95% CI=0.6612-0.8451). Furthermore, all TDI subdomains exhibited significant and comparable improvements post-treatment.

Conclusion

This meta-analysis indicates that the injection of PRP into the olfactory fissure or surrounding mucosal areas is an effective treatment for persistent refractory olfactory dysfunction.

Platelet-Rich Plasma for Patients with Olfactory Dysfunction: Myth or Reality? A Systematic Review

BACKGROUND

With promising outcomes, platelet-rich plasma (PRP) has recently been suggested as a treatment for olfactory dysfunction (OD).

METHODS

Clinical studies utilizing PRP in OD caused by COVID-19, trauma, anesthetic exposure, viral infection, and chronic rhinosinusitis were included in a systematic review.

RESULTS

Ten clinical studies were qualitatively analyzed. Six of these studies used the PRP for OD caused by COVID-19, one on OD after functional endoscopic sinus surgery, and three on post-infectious or post-trauma OD. The population included 531 patients, ranging in age from 15 to 63.

CONCLUSION

The use of PRP may be a risk-free and efficient therapeutic option with very encouraging outcomes. Indeed, it enhances olfactory perception in patients who not only exhibit COVID-19 infection aftereffects, but also in those who have lost their sense of smell due to trauma, rhinosinusitis, rhinitis, or even surgery. To evaluate the PRP's therapeutic benefits in OD patients and to compare the efficacy of different therapeutic protocols with regard to treatment schedules, there is an urgent need for focused controlled trials.