Letter to the Editor concerning “Correlation between the apex of lumbar lordosis and pelvic incidence in asymptomatic adult” by Pan C, et al. (Eur Spine J (2020); 29(3): DOI 10.1007/s00586-019-06183-y)

[摘要] We have read with interest the paper by Pan et al. In this study, the authors measured the apex of the lordosis (LLA) and correlated it with the pelvic incidence (PI). The corresponding regression formula was found to be LLA=−0.042 *PI+6.134. Apex positioning was frst used by Roussouly to describe his original classifcation of spinal sagittal balance [1] and was recently found by the French scoliosis study group to be crucial for decreasing postoperative complications in adult spinal disease surgery, especially proximal junctional kyphosis [2, 3]. Even though the authors present a plausible formula for locating the LLA, we have found several methodological and principal problems that we would like to point out to the editors.