Development of a patient-reported outcomes and experience measure for Orthognathic surgery: validation of the Northwick Park Orthognathic Questionnaire (NOQ).

Orthognathic surgery aims to correct dentoskeletal and facial discrepancies. The expected benefits are functional, cosmetic, and psychological. In a previous publication, this group assessed the determinants of patient satisfaction to formulate the Northwick Park Orthognathic Questionnaire (NOQ). The aim of the present study was to validate this questionnaire. A total of 118 postoperative patients prospectively completed the NOQ, 30 of whom completed the questionnaire a second time. The mean completion rate was 87.6 +/- 10%. Response reproducibility was high: 92% of patients gave identical responses (range 81-100%). The intra-class correlation coefficient (ICC) was 0.96 (0.96 +/- 0.072). Average test-retest scores for each domain were as follows (range in parenthesis): reasons for treatment 93% (60-100%), preoperative experience 96% (81-100%), preparation for surgery 95% (81-100%), inpatient experience 89% (55-100%), post-discharge experience 83% (55-100%), benefits of treatment 92% (71-100%), overall patient education 91% (62-100%). Internal validity using Cronbach's alpha was 0.72 (standard deviation 0.23, range 0.5-1). The results confirm the consistency of responses and the reliability of the information collected with the NOQ. The NOQ is a novel questionnaire and a valid metric to quantify a patient's perception of their experience. Its adoption may aid in making targeted improvements to patient care.