Participants were eligible for inclusion if they were adults aged 18 years or older and were undergoing or had undergone rhinoseptoplasty. Recruitment was conducted via telephone contact. Exclusion criteria included any cognitive or language impairment that interfered with the comprehension of the questionnaires, or refusal to complete any of the assessment instruments.

All questionnaires were administered by a single trained interviewer, a medical student under the supervision of physicians from the Department of Otolaryngology.

This study was designed to analyze the measurement properties and conduct the cross-cultural adaptation of a patient-reported outcome measure. Three instruments were used: the Short Form Health Survey (SF-36) and the Standardized Cosmesis and Health Nasal Outcomes Survey (SCHNOS) ‒ both previously translated and validated for Brazilian Portuguese ‒ and the Functional Rhinoplasty Outcome Inventory-17 (FROI-17).

Authorization to translate and validate the FROI-17 into Brazilian Portuguese was granted by its original authors.5 The translation and cultural adaptation process followed the internationally accepted guidelines proposed by Beaton et al.,3 ensuring semantic, idiomatic, experiential, and conceptual equivalence between the original and translated versions.

The translation process consisted of six phases: “Phase I” – initial translation; “Phase II” – synthesis of translations; “Phase III” – reverse translation; “Phase IV” – committee of experts; “Phase V” – pre-testing of the final version; and “Phase VI” – submission and consideration of all written reports.9

“Phase I” – Initial translation

“Phase I” consists of translating the questionnaire in its original English version into Portuguese Brazilian. For this stage, two translators (“TR1” and “TR2”) were invited to translate the questionnaire independently, without any type of communication or contact between them.

It was ensured that none of the translators had had previous contact specifically with the questionnaire to be translated, ensuring that they did not have prior knowledge of the content. The translators were native speakers of English and fluent in Portuguese Brazilian. “TR1” had previous knowledge of concepts and terms used in the health area, to provide a possibly more accurate translated version in the language of technical terms in the area. The “TR2”, on the other hand, had only knowledge of lay people about themes related to the health area without knowledge of technical terms.

The two versions translated into Portuguese Brazilian (T1 and T2) contained comments by the translators so that doubts and possible discrepancies could be discussed in “Phase II”.

“Phase II” – Synthesis of translations

“Phase II” consists of the synthesis of the translations (“T1” and “T2”) performed in “Phase I”. Under the coordination of the principal investigator, the translators met to produce a unified version (“T1‒2”), in which any discrepancies were discussed so that there was a consensus among the translators. The synthesis process was documented in a report so that the adjustment stage was reported with its proper justifications.

“Phase III” – Reverse translation

In “Phase III”, a third Translator (“TR3”), native in the Portuguese Brazilian language and fluent in the English language, who did not know the original questionnaire, back-translated the unified version (“T1‒2”) in Portuguese-Brazilian into English (“RT1-2”). The retro-translated version (“RT1‒2”) was sent to the original author and study team of the questionnaire for proper validation of the content. The original author and study team identified discrete items in which the content of the back translation did not meet the intended meaning of the original items. Based on this feedback, modifications in the content of the “RT1‒2” version, and “Phase II” was resumed so that the syntheses of the signaled points could be discussed and modified.

“Phase IV” – Expert committee

In “Phase IV”, the reverse-translated version (“RT1‒2”) was analyzed by a committee of experts to perform the cross-cultural equivalence of the questionnaire. This committee was composed of 4 professionals: 2 health professionals, 1 language professional, 1 methodologist and the translators involved in the process of “Phases I and II” (“TR1”, “TR2” and “TR3”). The authors of the original questionnaire were in contact with this committee during this process.

With the availability of the original questionnaire and the translations performed and their respective reports with their observations, the objective of this committee was to review the translations, remedy any discrepancies found between them and develop the pre-final version for field testing. This committee aimed to achieve equivalence from the original language to the translated version in the following areas:

Semantic equivalence – Assessed grammatical and vocabulary equivalence by comparing whether words have the same meaning during translation.

Idiomatic equivalence – Dealt with the difficulties in translating colloquial expressions from the English language.

Experiential or cultural equivalence – Sought to equate the terms used with the lived experience of the population to which it is intended.

Conceptual equivalence – Adapted the concepts of terms used between both languages.

“Phase V” – Submission and appraisal

In “Phase 5”, an audit of the entire process was carried out, where all reports and translated versions were presented. The original questionnaire study team (CD and IB) reviewed all phases to ensure that they were properly followed and that they were in accordance with the process.

Evaluations related to measures or outcomes of an instrument were performed. For statistical analysis, the SPSS software for Windows (version 22; SPSS inc.; USA, Armonk, NY). The Shapiro-Wilk test was used to determine the normality of the data. Parametric variables were described as mean and Standard Deviation (SD). Categorical variables were described as absolute numbers, percentage, and frequency. Clinimetric analyses were performed considering internal consistency, agreement, intra-rater reliability, convergent validity, and ceiling-floor effect.

For the sample calculation, we followed the recommendations of the guideline of the “COnsensus-based Standards for the selection of health Measurement Instruments” (COSMIN), which suggests that studies with the objective of performing an adequate evaluation of internal consistency, agreement, reliability and construct validity, the sample size can be classified as being considered an “adequate” sample when composed of 100 or more participants; a sample “good” when composed of between 50 and 99 participants; “moderate” when composed of between 30 and 49 participants; and a “small” sample when composed of fewer than 30 participants.

A total of 61 candidates were eligible to participate in the present study. Of these, 50 met the inclusion criteria. Ten candidates refused to answer the questionnaires, and one provided incomplete responses.

The mean age of participants was 50.20-years (SD = 15.07), with 56% identifying as female and 44% as male (Table 1).

Test-retest analysis showed that both reliability and internal consistency were adequate. Cronbach’s alpha was 0.93, indicating excellent internal consistency. Intraclass Correlation Coefficient (ICC) was 0.95, which is also considered excellent. These evaluations were performed for each domain of the questionnaire.

The Standard Error of Measurement (SEM), which reflects the measurement error, was calculated as: SEM=SD×√(1-ICC). The Minimal Meaningful Difference (MMD) represents the smallest change that can be interpreted as a real difference. It was calculated using the formula: MMD=1.96×√2×SEM. MMD was also expressed as a percentage (MMD%), providing an estimate of the relative random measurement error. The percentage was calculated as: MMD% = MMD-mean total score× 100; a minimum detectable change percentage <30% was considered acceptable, and <10% excellent (Tables 2 and 3).