Lithuanian version of nasolacrimal duct obstruction symptom scoring questionnaire. Cross-cultural adaptation and validation. Short- and long-term results

Abstract

Objectives: The objective of this study was to perform translation, cross-cultural adaptation and validation of the Lithuanian version of specific nasolacrimal duct obstruction symptom scoring (NLDO-SS) questionnaire and to evaluate short- and long-term results of endoscopic endonasal dacryocystorhinostomy (EN-DCRS) procedure.

Design, setting, participants: Permission for questionnaire translation, cross-cultural adaptation and validation was obtained from the authors of the original questionnaire. Translation, validation and cross-cultural adaptation were carried out according to generally accepted methodology. Validation study of the Lithuanian version of NLDO-SS (L-NLDO-SS) was performed, and short- and long-term results of EN-DCRS procedure were evaluated according to symptoms. In total, 44 patients were evaluated 2 weeks before the surgical intervention, a day before the surgery and 41 patients 2 months after the surgery, and again 10 months later.

Main outcome measures: We analysed the internal consistency and test-retest reliability of the L-NLDO-SS questionnaire. Cronbach's alpha was used to represent and evaluate internal consistency for ordinal responses. Validity was assessed by comparing scores between a control group of volunteers without NLDO and the NLDO group using Mann-Whitney test. To test the limiting score on which the sensitivity and specificity curves cross in identifying patients with NLDO, receiver operating characteristic (ROC) curve analysis was used. The pre- and post-operative scores were compared using the paired t-test.

Results: The results showed an acceptable internal consistency of L-NLDO-SS questionnaire, with Cronbach's alpha-.73 in the initial test group and .71 in the retest group. Pearson's correlation coefficient was .94 (P < .001), revealing good correlation between the initial scores and the retest scores. Our sample of healthy individuals had a mean L-NLDO-SS score of 11.42 (±12.69) points, and patients being scheduled for EN-DCRS had a mean L-NLDO-SS score of 27.45 (±9.81) points. Post-operatively mean L-NLDO-SS scores improved from 27.45 (±9.81) points to 4.45 (±6.29) points in the short term and to 5.83 (±4.17) in the long term, demonstrating the statistically significant responsiveness of the instrument over both timescales.

Conclusions: Lithuanian version of NLDO-SS questionnaire is a valid instrument for assessing patients with NLDO in the Lithuanian population. It demonstrated good internal consistency, reproducibility, validity and responsiveness.

Keywords: dacryocystitis; dacryocystorhinostomy; epiphora; nasolacrimal duct obstruction; symptom score questionnaire.