Assessment of symptoms
Pre-operative symptoms were assessed by interviews during each patient’s first visit and were documented in the medical records. Post-operative symptoms related to obstructive symptoms, such as swelling and discomfort or pain during or between meals, were assessed based on a three-point Likert-type scale 3 months postoperatively. Treatment outcomes were classified into three scales as follows: obstructive symptoms completely subsided (complete resolution), symptoms partially improved (partial resolution), or symptoms not changed or worsened (non-resolution).