Effect of an Intraoperative Polynucleotide Injection on Scar Quality After Thyroidectomy and Parathyroidectomy

The goal of this clinical trial is to learn whether a single polynucleotide injection can improve scar quality after thyroid or parathyroid surgery in adults. It will also assess the safety of the injection. The main questions this study aims to answer are the following: Does a single polynucleotide injection improve scar quality 24 weeks after surgery? Does it improve scar appearance and symptoms such as pain, itching, hardness, or tightness? Are there any side effects or wound problems related to the injection? Researchers will compare PLINEST One PN-HPT, a solution containing polynucleotides, with sterile saline, which does not contain polynucleotides. After the surgical incision is closed, participants will receive one injection along the incision line. Participants will be randomly assigned to receive either PLINEST One PN-HPT or saline. Scar healing and appearance will be checked after surgery. Formal scar assessments will be performed at 4, 12, and 24 weeks. Scar quality will be assessed using patient and researcher scar rating scales, scar measurements, photographs, symptoms, and participant satisfaction.

Inclusion Criteria: * Adults aged 40 to 60 years. * Scheduled to undergo open thyroidectomy, thyroid lobectomy, or parathyroidectomy through a standard anterior cervical (Kocher) incision. * Undergoing anterior neck surgery for the first time. * Able to provide written informed consent. * Willing to attend the planned postoperative follow-up visits. * Able and willing to comply with the study procedures. Exclusion Criteria: * Younger than 40 years or older than 60 years. * Previous anterior neck surgery. * Pre-existing scar in the planned incision area. * History of hypertrophic scar or keloid formation. * Previous radiotherapy to the neck. * Active dermatologic disease involving the anterior neck. * Active local or systemic infection. * Uncontrolled diabetes mellitus. * Current use of systemic corticosteroids or immunosuppressive medications. * Pregnancy or breastfeeding. * Known hypersensitivity to fish, salmonid-derived products, polynucleotides, or any component of PLINEST One. * Coagulation disorder or clinically significant bleeding tendency. * Use of anticoagulant therapy that constitutes a contraindication to intradermal injection. * Any contraindication to mesotherapy, intradermal injection, or injectable biostimulant procedures. * Inability or unwillingness to comply with the planned follow-up assessments.