A comparative randomized study of injecting platelet-rich plasma solution versus normal saline injection on olfactory outcomes following endoscopic sinus surgery in patients with chronic sinusitis accompanied by nasal polyps : a single-center clinical trial

The study of the effect of platelet-rich plasma injection on olfactory outcomes following endoscopic sinus surgery in patients with chronic sinusitis with polyps.

A randomized, parallel-group, controlled clinical trial with two groups, involving a total of 40 patients. Block randomization with blocks of four was used for randomization.

In the intervention group, 1 milliliter of platelet-rich plasma (PRP) will be injected intranasally. The PRP will be injected using a 1cc syringe with a 30-gauge needle into the olfactory region, covering an area of 1 square centimeter, under endoscopic visualization, and performed by a physician. In the control group, 1cc of normal saline will be injected into the same area. Patients will be blinded to their group allocation and the type of intervention performed. The data collector will also be blinded to both the group allocation and the injected substance. Additionally, the individual responsible for data collection will not be present during the injection procedure. Preoperative and 6-month postoperative assessments will be performed by the same physician using the I-SIT olfactory scale.

Inclusion criteria: Patients aged 15 to 50 years with nasal polyps, having varying degrees of olfactory dysfunction based on the Iran olfactory identification test score, and with a duration of anosmia of less than 2 years. Exclusion criteria: A history of head trauma, previous sinonasal surgery, smoking, congenital anosmia, and the presence of systemic disorder, Additionally, patients with missing data or those lost to follow-up will also be excluded from the study.

In the intervention group, platelet-rich plasma injection will be administered to patients with polyposis during endoscopic sinus surgery.

Improvement of olfaction

The random allocation of patients into two groups is done by the stratified block randomization method. In such a way that first the eligible patients are referred in the order of entry They are classified according to age and sex. Then based on blocks of 4 (consisting of two groups A and B and two repetitions for each) that are randomly selected from among all the possible cases of permutations and assigned to the desired group they find These blocks were created using the statistical software R version 4.0.2.

In this study, a single-blind method is used. This means that the patient is aware of their participation in the study but will not be informed about the type of intervention, whether it is normal saline or platelet-rich plasma. However, the physician and the principal investigator are aware of the type of injected substance and the selected individuals.