Postoperative Surgical Scar

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.