Study Procedures
Pilot study: After providing written informed consent, participants completed a self-administered CSOC questionnaire. After filling out the CSOC, each patient was asked how well they had understood each item.
Content validity: We sent an e-mail to the experts alongside an explanatory cover letter, reviewer instructions, definitions of terms, and a content-review questionnaire. The members of the panel responded by e-mail. In the content-review questionnaire, experts were asked to judge how representative the questionnaire items are of QOL in COS using a 4-point scale: 1 = not representative, 2 = somewhat representative, 3 = quite representative and 4 = highly representative. Experts were prompted to evaluate the clarity of item construction and wording. Finally, suggestions for addition or deletion of items were requested.
Validation process: After providing written informed consent, participants completed a self-administered CSOC questionnaire at the following time points:within45 days before sialendoscopy, in the preoperative area before sialendoscopy and 90-120 days after sialendoscopy. SF-36 and visual analogue scale (VAS)fordiscomfort were completed at the first and third time points. The CSOC filled out during the validation process comprised 18 items according to the results of the pilot study and the content validityassessment (Supplementary Table 3).