Proximal junctional kyphosis in Lenke 5 AIS patients: the important factor of pelvic incidence

Abstract Background The purpose of the study was to investigate whether pelvic incidence (PI) will affect occurrence PJK in Lenke 5 AIS patients after correction surgery and try explore a better surgical scheme based on PI. Methods 5C that underwent with minimum 2-year follow-up were identified. Demographic radiographic data collected preoperatively, postoperatively, at final follow-up. comparison between Non-PJK group conducted subgroup analysis performed preoperative value PI potential mechanism PJK. Clinical assessments using Scoliosis Research Society (SRS)-22 questionnaire. Results mean Cobb angle TL/L curve 53.4°±8.6. At follow-up, drastically decreased 7.3°±6.8 ( P < 0.001). 18.6 %, 21.9 % (7/32) low (PI 45°) 15.8 (6/38) high ≥ 45°), there no statistical difference two groups (χ 2 = 0.425, 0.514). For patients, is significant where UIV located regards TK apex subgroups 1.103, 0.401). more likely occur when cephalad than caudal (31.25 vs. 4.7 0.038). There selection LIV groups. Conclusions (< (≥45°), but main risk factor should be different. PI, overcorrection LL strictly avoided during surgery. not or thoracic kyphosis retain mobile segments.