Intraoperative Use of Platelet-Rich Plasma in Tympanoplasty: Effects on Graft Success and Audiological Outcomes - A Prospective Controlled Trial

Study design and ethics This prospective, single-center, randomized controlled trial was conducted at the Otolaryngology-Head and Neck Surgery Clinic of Sisli Hamidiye Etfal Training and Research Hospital, Istanbul, between April 1 and June 30, 2023. The protocol received ethics committee approval (decision no. 3857, April 4, 2023). All participants provided written informed consent before enrolment. The trial was conducted in accordance with the Declaration of Helsinki.

Participants Adults aged 18-65 years were eligible if they had a central tympanic membrane perforation present for at least six months without active discharge in the preceding three months, were able to undergo and cooperate with preoperative pure-tone audiometry, and were available for follow-up. Exclusion criteria were: planned concurrent mastoidectomy, cholesteatoma on preoperative imaging or intraoperative inspection, a history of ventilation tube insertion on the affected side, revision surgery, uncontrolled hypertension or diabetes mellitus, coagulation disorder or antiplatelet/anticoagulant therapy, anaemia (Hgb <12 g/dL) or thrombocytopaenia (platelets <150,000/μL), active malignancy, and serious psychiatric illness.

Randomization Patients who met inclusion criteria were allocated by simple alternation: the first eligible patient was assigned to the PRP group, the second to the control group, the third to the PRP group, and so on. Patients were not informed of their group assignment (single-blind design). Surgeons were necessarily aware of group allocation.

Sample size Sample size was calculated with G*Power version 3.1.6. Based on an expected large effect size (Cohen's d = 0.62) derived from comparable prospective cohort data, a two-sided α of 0.05, and a power of 80%, the required sample was 48 patients (24 per group).

PRP preparation PRP was prepared manually at the start of each operation in the PRP group. After intravenous access was established, 8.5 mL of venous blood was drawn into a glass tube containing 1.5 mL of acid citrate dextrose (ACD-A solution; Becton Dickinson, Plymouth, UK) using an 18-gauge needle. The tube was centrifuged at 419 × g (2,500 rpm) for 8 minutes in a Tomos Centrifuge 802B (Tomos Life Science Group, Shanghai, China), balanced against a tube of equal weight containing normal saline. The platelet-rich buffy coat layer and the overlying plasma were carefully aspirated using a spinal cannula into a sterile, anticoagulant- free 10-mL tube. This tube was then centrifuged at 822 × g (3,500 rpm) for 8 minutes. The upper two-thirds of the supernatant were discarded, and the remaining platelet concentrate was gently resuspended by inverting the tube several times. This final product was used to saturate the spongostans immediately before placement.