• Intra-operative time [ Time Frame: 1 day ] [ Designated as safety issue: Yes ]
  
• Intra-operative blood loss [ Time Frame: 1 day ] [ Designated as safety issue: Yes ]
  
• Pain, postoperative [ Time Frame: 14 days ] [ Designated as safety issue: Yes ]
  

• Postoperative bleeding and other adverse effects [ Time Frame: 14 days ] [ Designated as safety issue: Yes ]
  

Tonsillectomy is one of the most common procedures performed by otolaryngologists. Intraoperative bleeding is a significant problem which requires hemostasis and causes prolonged operative time. Several different techniques are used to perform this operation. Efficacy in hemostasis and tissue trauma from different operative techniques may result in different operative time and different degrees of morbidity including intraoperative blood loss, postoperative pain and hemorrhage. The vessel sealing system has been widely used in head and neck surgery because of its effectiveness and safety. It was also found quite effective and safe in tonsillectomy procedures, providing excellent hemostasis and minimal tissue trauma. This study was planned to compare vessel sealing system tonsillectomy (VSST) to the traditional cold knife tonsillectomy (CKT) with special regard to intraoperative bleeding, operative time, postoperative pain and hemorrhage. Inclusion criteria are patients planned for tonsillectomy for indications of chronic tonsillitis or obstructive sleep apnea and written informed consent form is given from patient or patient's parents (in case of pediatric patient). Exclusion criteria are pregnancy, history of bleeding disorders, unilateral tonsillectomy, much different size of both tonsils (If the difference is more than or equal to 2, it will be defined as much different in size in this study), patient unable to understand evaluation method or unable to be contacted via telephone. Outcome measurements are the following.

1. Operative time (minutes) will be started at the time of incision and ended at the time of complete hemostasis. After tonsillectomy on the first side is finished, 5-10 minutes is the lag time before tonsillectomy on the second side will be started in order to observe re-bleeding after operative time is recorded. If there is re-bleeding, the operative time will be changed and measured from the same starting time to the time of last complete hemostasis.
2. Amount of blood loss (milliliter) will be measured from amount of fluid including blood and saliva in the container and gauze. Measurement will be started at the time of incision and ended at the time of complete hemostasis in the same manner of operative time.
3. Pain score, postoperative hemorrhage or other adverse effects that the research assistant will record on post-op day 0-14 by using direct and telephone interview.