Effects of photobiomodulation with red and infrared low-level laser diodes in individuals undergoing rhinoplasty at a single centre in São Paulo, Brazil: protocol for a randomised, double-blind, controlled clinical trial.

introductionOedema and ecchymosis are common after rhinoplasty and may delay recovery. Photobiomodulation (PBM) has been shown to have analgesic, anti-inflammatory and regenerative effects; however, its role in rhinoplasty remains underexplored. This study aims to evaluate the effectiveness of PBM in reducing periorbital oedema in patients undergoing rhinoplasty. METHODS AND ANALYSIS: This is a single-centre, randomised, controlled, double-blind clinical trial that will include 60 participants allocated into two groups: a control group (n=30), receiving sham PBM before surgery, and an intervention group (n=30), receiving preoperative PBM followed by rhinoplasty. PBM will be delivered using a cluster device containing three red low-level laser diodes (660 nm, 150 mW each) and three infrared low-level laser diodes (808 nm, 150 mW each), applying 12 J per point for 80 s at three standardised facial sites. The intervention (PBM or sham) will be applied 1 hour before the surgical procedure. The primary outcome will be periorbital oedema on postoperative day 3, assessed using the Hoffmann clinical scale. Standardised photographic analysis using ImageJ software will be employed as a complementary measure. Secondary outcomes will include oedema at additional follow-up time points, ecchymosis, postoperative pain assessed using the visual analogue scale, nasal tip skin thickness, analgesic consumption and patient-reported aesthetic and functional outcomes assessed using the Standardized Cosmesis and Health Nasal Outcomes Survey (SCHNOS) questionnaire. Follow-up assessments will be conducted at 3, 7, 30, 60 and 90 days, as well as at 6 and 12 months. Data will be analysed using parametric or non-parametric tests according to data distribution. ETHICS AND DISSEMINATION: The study was approved by the Research Ethics Committee of Irmandade da Santa Casa de São Paulo (protocol number: 7503097), will be conducted in accordance with the Declaration of Helsinki and current Brazilian regulations for research involving human participants and registered at ClinicalTrials.gov (NCT07033039). Written informed consent will be obtained from all participants prior to enrolment. The results will be disseminated through peer-reviewed scientific publications, presentations at national and international scientific conferences, and communication of findings to interested participants. TRIAL REGISTRATION NUMBER: NCT07033039.