Surgical Treatment for Patients With Obstructive Sleep Apnea by Using Da Vinci SP Surgical System

Inclusion Criteria: 1. Age 18 years or more. 2. OSA with AHI ≥ 15 3. Has failed, refuses, or is unable to tolerate CPAP therapy 4. Indication of resection of tongue base with/without other invasive surgical procedure for OSA (i.e. tongue base resection only or multi-level surgery with tongue base resection) 5. ASA physical status classification 1-2 and adequate organ function 6. Patients willing and able to comply with study protocol requirements and follow-up 7. Informed consent Exclusion Criteria: 1. BMI\>35 2. Mouth opening too narrow for TORS or trismus 3. Betel nut chewing 4. Suspicious cancer diagnosis 5. Prior head-and-neck surgery (note: prior invasive therapy for OSA allowed) 6. Other medical condition or anatomical factor not suitable for TORS, including subject with congenital malformations in the larynx, throat or tongue; 1. Subject with an American Society of Anesthesiologists (ASA) score of Grade 4 or above during preoperative evaluation 7. Active infectious disease 8. Can't follow trial-required procedures 9. Severe concomitant illness that drastically shortens life expectancy or increases risk of therapeutic interventions * Severe heart disease (NYHA functional class III-IV) * Severe lung disease (GOLD Group C-D) 10. Long-term use of anti-coagulant 11. Patients with coagulopathy 12. Emergency surgery 13. Subject for whom any additional surgeries are planned for OSA within the study period, after the surgery in which the da Vinci SP System was used 14. Subject is pregnant or suspected to be pregnant