1.1 Non-Temperatured Controlled Radiofrequency in the Treatment of Patients with Obstructive Sleep-Disordered Breathing: How We Do it? Paraya Assanasen, M.D. , Weerachai Tantinikorn, M.D., Wish Banhiran, M.D., Choakchai Metheetrairut, M.D. Department of Otolaryngology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand Snoring is an initial end of sleep disorder breathing (SDB) spectrum. It can lead to terminal end, obstructive sleep apnea syndrome. Treatments comprise of non-surgical and surgical treatments, and surgical treatment is an alternative when non-surgical treatment fails. The novel radiofrequency procedures are technically simple, minimally invasive and associated with minimal postoperative pain and discomfort compared to traditional surgical procedures. It can be performed as an outpatient basis under local anesthesia with a low complication rate and excellent therapeutic results. A result of heating by radiofrequency produces ablation to collateral tissue surrounding the target tissue site. Over a course of several weeks following the initial treatment, firmer fibrous tissues are formed and they reduce the tissue volume with less vibration. Temperatured controlled radiofrequency (TCRF) has advantages in monitoring tissue impedance and temperature during application and results in a precision of lesion dimension control. However, the radiofrequency generator with monitoring equipments and specific needle electrodes are very expensive. We have used non-temperatured controlled radiofrequency (NTCRF) to perform radiofrequency- assited uvulopalatoplasty (RAUP) and/ or volumetric tissue reduction of nasal mucosa, soft palate, and base of tongue under local anesthesia or as an adjunct with uvulopalatopharyngoplasty (UPPP) under general anesthesia in our institute successfully for several years without serious complications. Its major advantage over TCRF is cost-effectiveness. It is relatively inexpensive, safe, well-tolerated, and effective in the treatment of patients with obstructive SDB. We present our technique in performing RAUP, volumetric tissue reduction of nasal mucosa, soft palate, and base of tongue by using NTCRF in this study.