Topical Versus Injection PRP for Olfactory Dysfunction

Summary

The goal of this clinical trial is to determine whether two different delivery methods of autologous platelet-rich plasma (PRP) can improve olfactory function in adults with persistent olfactory dysfunction lasting more than three months. The main questions it aims to answer are:

1. Does carrier-assisted topical application of PRP lead to comparable or better improvement in smell function than intranasal injection of PRP?
2. Which method provides greater patient comfort and fewer adverse effects?

Researchers will compare carrier-assisted topical PRP application to intranasal PRP injection to see if one approach is more effective in restoring olfactory function.

Participants will:

1. Receive a single PRP treatment delivered either by injection or via a PRP-soaked carrier placed into the olfactory cleft.
2. Continue daily olfactory training for three months following the intervention.
3. Undergo smell testing (Sniffin' Sticks) before and after treatment and complete quality-of-life questionnaires.

Conditions

• Olfactory Dysfunction
• Anosmia
• Hyposmia

Interventions

PROCEDURE

Intranasal Injection of Autologous PRP

Under topical anesthesia and decongestion, approximately 1 mL of freshly prepared autologous platelet-rich plasma will be injected into multiple sites of the olfactory cleft mucosa bilaterally using a 25-gauge needle under endoscopic guidance. Single treatment session.

PROCEDURE

Carrier-Assisted Topical Application of Autologous PRP

Four pieces of sterile, bioabsorbable carrier (Gelfoam sponge) will be soaked with approximately 5 mL of freshly prepared autologous platelet-rich plasma. Under endoscopic guidance, two pieces will be placed gently into each olfactory cleft, ensuring contact with the olfactory mucosa. Carriers will remain briefly to allow PRP diffusion before dissolving naturally or being removed. Single treatment session.

COMBINATION_PRODUCT

platelet-rich plasma

This study adopts a fully automated, closed-system PRP preparation technique to ensure the stability of the blood product. A total of 60 mL of whole blood is drawn and processed using the Phoenix Q1 centrifuge (TFDA Medical Device Manufacturing License No. 004461) for blood component separation in a closed, sterile environment. An optical sensor identifies and automatically collects the buffy coat layer (rich in platelets and monocytes), yielding approximately 6 mL of autologous platelet-rich plasma (PRP). The centrifugation and PRP collection process takes about 5 minutes. Compared with traditional methods requiring manual identification and collection, this approach enhances the precision and safety of centrifugation-based preparation.

DEVICE

olfactory training

Participants will perform olfactory training for 12 weeks following the PRP intervention. Training is conducted twice daily using four odor bottles containing standardized odorants from Sigma-Aldrich (Germany): lemon (citronellal, #27470), rose (phenylethanol, #77861), clove (eugenol, #W246700), and eucalyptus (eucalyptol, #C80601). Each odor is sniffed gently for about 20 seconds, with a 20-second pause between bottles. Participants will record the perceived intensity of each odor in a training diary after every session.

Sponsors & Collaborators

• Taipei Veterans General Hospital, Taiwan

  lead OTHER_GOV

Study Design

Allocation

RANDOMIZED

Purpose

TREATMENT

Masking

DOUBLE

Model

PARALLEL

Eligibility

Min Age

18 Years

Max Age

80 Years

Sex

ALL

Healthy Volunteers

No

Timeline & Regulatory

Start

2025-10-01

Primary Completion

2027-12-31

Completion

2028-12-31

Countries

• Taiwan

Study Locations