Objective: To evaluate the incidence and risk factors associated with proximal junctional kyphosis (PJK) in patients with adolescent idiopathic scoliosis (AIS) after correction surgery.
Methods: PubMed, Embase, and Cochrane Library were searched from inception until August 2018 to obtain relevant studies. After study selection and data extraction, statistical analysis was performed with RevMan 5.3. The odds ratios (ORs) and weight mean differences (WMDs) with 95% confidence intervals (CIs) for all available factors were analyzed using fixed or random effects models.
Results: A total of 7 studies were included in this meta-analysis. The overall incidence of PJK in AIS was 14% (95% CI, 8%-20%). Among the potential risk factors, proximal implants with screws (OR, 1.64; 95% CI, 1.13-2.39; P = 0.010), instrumentation types with all screws (OR, 1.78; 95% CI, 1.19-2.67; P = 0.005), larger preoperative thoracic kyphosis (TK) (WMD, 7.50; 95% CI, 5.75-9.26; P < 0.001), larger preoperative lumbar lordosis (LL) (WMD, 4.85; 95% CI, 2.79-6.92; P < 0.001), larger postoperative LL (WMD, 2.00; 95% CI, 0.09-3.91; P = 0.040), greater change in TK (WMD, -6.75; 95% CI, -9.72 to -3.78; P < 0.001), and greater change in LL (WMD, -3.26; 95% CI, -5.40 to -1.12; P = 0.003) were identified as risk factors for PJK.
Conclusions: The incidence of PJK in patients with AIS was 14%. Proximal implants with screws and instrumentation types with all screws were significantly associated with increased occurrence of PJK. Larger preoperative TK, larger preoperative LL, larger postoperative LL, greater TK change, and greater LL change were also identified as risk factors for PJK in AIS after correction surgery.
Keywords: Adolescent idiopathic scoliosis; Incidence; Meta-analysis; Proximal junctional kyphosis; Risk factors.
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