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

Importance: Selective, 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. Objective: There 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 Participants: A 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. Results: NDII 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, P < 0.001). The intraclass correlation coefficient of the overall score was moderate (ICC = 0.683, P < 0.001). Conclusions and Relevance: NDII is a recognized, previously validated quality-of-life (QOL) tool for the identification of ND-related dysfunction. This validated Spanish version will allow clinicians to adequately assess the neck and shoulder-related QOL for the Spanish-speaking population who are under-represented in head and neck research.