1. Bombardier C. Outcome assessments in the evaluation of treatment of spinal disorders: summary and general recommendations. Spine (Phila Pa 1976) 2000 25:3100–3.

2. Ko S, Chae S. Correlations between the SF-36, the Oswestry-Disability Index and Rolland-Morris Disability Questionnaire in patients undergoing lumbar decompression according to types of spine origin pain. Clin Spine Surg 2017 30:E804–8.

3. Chiu TT, Lam TH, Hedley AJ. Correlation among physical impairments, pain, disability, and patient satisfaction in patients with chronic neck pain. Arch Phys Med Rehabil 2005 86:534–40.

4. DeVine J, Norvell DC, Ecker E, et al. Evaluating the correlation and responsiveness of patient-reported pain with function and quality-of-life outcomes after spine surgery. Spine (Phila Pa 1976) 2011 36(21 Suppl): S69–74.

5. Vernon H, Mior S. The Neck Disability Index: a study of reliability and validity. J Manipulative Physiol Ther 1991 14:409–15.

6. Ware JE, Kosinski M, Keller SD. SF-36 physical and mental health summary scales: a user’s manual. Boston (MA): Health Assessment Lab; 1994. 7. Howell ER. The association between neck pain, the Neck Disability Index and cervical ranges of motion: a narrative review. J Can Chiropr Assoc 2011 55:211–21.

8. Pietrobon R, Coeytaux RR, Carey TS, Richardson WJ, DeVellis RF. Standard scales for measurement of functional outcome for cervical pain or dysfunction: a systematic review. Spine (Phila Pa 1976) 2002 27:515–22.

9. Resnick DN. Subjective outcome assessments for cervical spine pathology: a narrative review. J Chiropr Med 2005 4:113–34.

10. Vernon H. The Neck Disability Index: state-ofthe-art, 1991-2008. J Manipulative Physiol Ther 2008 31:491–502.

11. MacDermid JC, Walton DM, Avery S, et al. Measurement properties of the neck disability index: a systematic review. J Orthop Sports Phys Ther 2009 39:400–17.

12. Hains F, Waalen J, Mior S. Psychometric properties of the neck disability index. J Manipulative Physiol Ther 1998 21:75–80.

13. Miettinen T, Leino E, Airaksinen O, Lindgren KA. The possibility to use simple validated questionnaires to predict long-term health problems after whiplash injury. Spine (Phila Pa 1976) 2004 29:E47–51.

14. Andrade-Ortega JA, Ceron-Fernandez E, Ribeiro-Gonzalez M, Garcia-Llorent R, Almecija-Ruiz R, Delgado-Martinez AD. Pain, disability and quality of life in chronic nonspecific neck pain. Phys Med Rehabil Int 2016 3:1094. 15. Song KJ, Choi BW, Choi BR, Seo GB. Cross-cultural adaptation and validation of the Korean version of the neck disability index. Spine (Phila Pa 1976) 2010 35:E1045–9.

16. Cook C, Richardson JK, Braga L, et al. Cross-cultural adaptation and validation of the Brazilian Portuguese version of the Neck Disability Index and Neck Pain and Disability Scale. Spine (Phila Pa 1976) 2006 31:1621–7.

17. Van der Velde G, Beaton D, Hogg-Johnston S, Hurwitz E, Tennant A. Rasch analysis provides new insights into the measurement properties of the neck disability index. Arthritis Rheum 2009 61:544–51.

18. Lee H, Nicholson LL, Adams RD, Maher CG, Halaki M, Bae SS. Development and psychometric testing of Korean language versions of 4 neck pain and disability questionnaires. Spine (Phila Pa 1976) 2006 31:1841–5.

19. Lee JS, Suh KT, Kim JI, Lee HS, Goh TS. Validation of the Korean version of the neck pain and disability scale. Asian Spine J 2013 7:178–83.