Table 2 Key changes to the Nasal Airway Obstruction Study (NAIROS) protocol

2.0, 31 Jul 2017

• Specification of the location of the RSI within the mometasone SmPC

3.0, 20 Nov 2017

• Specification of the decongestant spray to be used alongside the nasal patency measurements (xylometazoline) and classification of the decongestant spray as a NIMP

• Clarification of the exclusion criteria regarding the use of orally administered steroids and updating the exclusion criteria to exclude patients who have an external bony deformity that is likely to make a substantial contribution to the nasal obstruction

4.0, 11 Jun 2018

• Update to the mometasone RSI

• Update the exclusion criteria from any history of intranasally administered recreational drug use to any history of intranasal recreational drug use within the past 6 months

• Clarify the clinical examination procedure to state that patients who request local anaesthetic for nasal endoscopy may have the nasal endoscopy assessment carried out after the other trial assessments have been completed

• Clarification of the timing for the surgical intervention to state that patients randomised to septoplasty must have their septoplasty anytime within 8 weeks of randomisation

4.1, 21 Dec 2018

Addition of a 4-week window to the timeline for surgery for use in extenuating circumstances (i.e. 8 weeks + 4 weeks)

5.0, 16 Jan 2019

• Change the window for the 6-month visit from ± 2 weeks to − 2 weeks/+ 4 weeks to maximise collection of the primary outcome measure

• Clarification of management of patients between the 6-month and 12-month follow-up visits

• Clarification of management and options for participants who wish to discontinue with their allocated treatment and explore other surgical or medical treatments as part of standard NHS care

• State that discontinuation of allocated treatment does not constitute withdrawal from the trial. Update to the RSI for the surgical intervention