Answer to the Letter to the Editor of B. Hu et al. concerning “Demographics, presentation and symptoms of patients with Klippel-Feil syndrome: analysis of a global patient-reported registry” by Nouri et al. [Eur Spine J; (2019) 28(10): 2257–2265]

[摘要] Thank you for your interest in our paper. The purpose of our research was to investigate data of patients with KFS, a rare disease, to describe the demographics and identify possible associations with health problems based on the reported data—such an analysis is inherently explorative. While it is true that generally speaking Fisher’s exact test is used when 20% of cells with an expected value of less than 5 are present in a 2×2 comparison, this test has also been considered to be conservative [1]. The concern that not having used this test has led to inappropriate conclusions is incorrect.