The Effect of Platelet-Rich Plasma and Hyaluronic Acid Nasal Injections in the Treatment of Traumatic Olfactory Dysfunction.

Objective: Platelet-rich plasma (PRP) has been injected into the olfactory cleft to treat olfactory dysfunction related to coronavirus disease 2019. In this study, we aimed to evaluate the effect of PRP combined with hyaluronic acid (HA) nasal injection in the treatment of traumatic olfactory dysfunction. Methods: Patients who had lost olfactory function after experiencing head trauma and were willing to receive PRP and HA nasal injections for treatment were enrolled. Before nasal injection, 10 cc of blood was drawn from the patients. The drawn blood was injected into a centrifuge tube for processing, and finally, 5 cc of the PRP mixed with HA was drawn out using an empty syringe. The PRP mixed with HA was injected into the upper part of the middle nasal septum and the medial side of the middle turbinate of the patient's nasal cavity under a nasal endoscope. The olfactory function of each patient was evaluated by the phenyl ethyl alcohol (PEA) odor detection threshold test before and at both 1 and 3 months after nasal injection and the traditional Chinese version of the University of Pennsylvania Smell Identification Test at 3 months after nasal injection. Results: A total of 28 patients received PRP and HA nasal injections between August and December of 2023 and came back for evaluation of the effect. In all, 20 (71.4%) patients felt their olfactory function improved 1 month after injection, and 24 of 28 (85.7%) patients reported their olfactory function improved at 3 months after injection. The bilateral or unilateral PEA threshold decreased in 22 (78.6%) patients 1 month after injection, and decreased in 15 (53.6%) patients 3 months after injection. Conclusions: Our results show that PRP and HA nasal injections were associated with favored patient-reported outcomes and improved the olfactory threshold in the treatment of traumatic olfactory dysfunction.