Answer to the Letter to the Editor of Changyu Pan et al. concerning “Global tilt: a single parameter incorporating spinal and pelvic sagittal parameters and least affected by patient positioning” by Obeid I et al. (Eur Spine J; [2016] 25:3644–3649)

[摘要] The question raised in the Letter to the Editor concerning Global Tilt parameter [1] is very important to understand spinal balance, and we completely agree with the authors.