A Meta-analysis of the incidence and risk factors of proximal junctional kyphosis after correction surgery for Scheuermann′s disease

English Keywords:Scheuermann′s disease  Proximal junctional kyphosis  Risk factors  Meta analysis

English Abstract:

  【Abstract】 Objectives: To investigate the incidence of proximal junctional kyphosis (PJK) after orthopaedic surgery for Scheuermann′s disease and associated risk factors through Meta-analysis. Methods: Database such as PubMed, Embase, Cochrane Library, CNKI, and Wanfang were searched from inception to November 2021 for studies related to the occurrence of PJK in patients with Scheuermann′s disease after orthopedics surgery. The Newcastle-Ottawa Scale(NOS) was used to evaluate the quality of the included studies, and the outcome indicators of the included studies were extracted, including the incidence of PJK, age and gender, the surgical procedure, relative position of proximal instrumented vertebra(PIV) to proximal end vertebra(PEV), the position of PIV, the amount of kyphosis correction, the pelvic incidence(PI), and pre- and post-operative lumbar lordosis(LL), pelvic tilt(PT), sacral slope(SS), and thoracic kyphosis(TK), PI-LL, correction loss, and TK correction rate. Statistical analyses were performed using Revman 5.3 software. A fixed or random effects model was used with odds ratios(OR) for single rate and weighted mean difference(WMD) for continuous variables, and confidence intervals CI was 95%. Results: A total of 17 high quality cohort studies were included in this meta-analysis, involving 784 patients, of which 213 patients with Scheuermann′s disease developed PJK after corrective surgery(PJK group) and the other 571 cases were included in non-PJK group. The follow-up time was 35.72±14.16 months. Meta-analysis showed that the overall incidence of PJK was 23%(RD 0.23, 95%CI 0.13-0.33, P<0.00001), and there were significant differences between groups in PIV position(OR 0.37, 95%CI 0.16-0.85, P=0.02) and the amount of correction of kyphosis(OR 4.52, 95%CI 1.72-11.90, P=0.002), with a significantly higher incidence of PJK when the fixed position of the upper vertebrae was between T5 and T8 and also when the amount of kyphosis correction was >50%. There was no significant difference between groups in PI(WMD -1.51, 95%CI -4.75-1.73, P=0.36), age(WMD 0.15, 95%CI -1.80-2.09, P=0.88), sex(OR 1.08, 95%CI 0.39-2.97, P=0.88), surgical procedure(OR 1.2, 95%CI 0.65-2.22, P=0.55), relative position of PIV to PEV(OR 0.6, 95%CI 0.32-1.14, P=0.12), preoperative LL(WMD -1.22, 95%CI -5.86-3.41, P=0.60), postoperative LL(WMD -1.43, 95%CI -6.02-3.16, P=0.54), preoperative PT(WMD 0.63, 95%CI -1.82-3.08, P=0.62), postoperative PT(WMD 4.03, 95%CI -1.71-9.78, P=0.17), preoperative SS(WMD -0.10, 95%CI -3.40-3.19, P=0.95), postoperative SS(WMD -1.15, 95%CI -3.95-1.67, P=0.42), preoperative TK(WMD 1.38, 95%CI -1.21-3.98, P=0.30), postoperative TK(WMD 3.13, 95%CI -0.56-6.817, P=0.10), PI-LL(WMD -2.40, 95%CI -6.92-2.12, P=0.30), correction loss (WMD -0.49, 95%CI -2.92-1.93, P=0.69), and correction rate of TK(WMD -4.22, 95%CI -12.63-4.18, P=0.32). Conclusions: The incidence of PJK after orthopaedic surgery in patients with Scheuermann′s disease was 23%, with a significant increase in the incidence of PJK when the fixation position of the upper vertebrae was between T5 and T8 and when the amount of kyphosis correction was >50%.