Cross-Cultural Adaptation and Translation of the Neck Dissection Impairment Index (NDII) into Spanish.

ImportanceSelective, modified radical, and radical neck dissections are common surgical procedures that can result in significant musculoskeletal issues of the neck and shoulder. Quality-of-life evaluations after neck dissection must assess and quantify these dysfunctions to allow subsequent comparison of outcomes after different treatments.ObjectiveThere is no validated Spanish-language questionnaire designed to evaluate neck and shoulder dysfunction after cervical lymphadenectomy. We therefore sought to translate a version of the Neck Dissection Impairment Index (NDII) into Spanish.Design, Settings, and ParticipantsA three-phased approach was used. Phase 1: The NDII was translated from English to Spanish using a "forward and backward" translational technique following international guidelines. Phase 2: The questionnaire was administered to six patients from our head and neck surgery clinic who were bilingual and fluent in both English and Spanish. Phase 3: The final version was administered prospectively to 34 patients with prior history of neck dissection (ND). These patients were asked to complete the questionnaire a second time 3 to 6 weeks after their first response. Test-retest reliability was calculated with Spearman's correlation. Internal consistency was elicited using Cronbach's alpha.Main Outcome(s) and Measure(s)NDII score at initial administration and follow-up administration 6 weeks later, demographic data.ResultsNDII was successfully translated and validated into Spanish. Cronbach's alpha revealed high internal consistency at both the first time point 0.95 (mean standardized score: 95 (88.1, 97.5), 95% CI: 0.89, 0.97) and at the second time point 0.90 (mean standardized score: 92.5 (80.6, 100.0), 95% CI: 0.81, 0.95). The Spearman's correlation for test-retest reliability of overall score was strong (rho = 0.772,