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Table 3 Comparison of the screw pull-out group and the normal group

From: Comparative analysis of clinical factors associated with pedicle screw pull‐out during or immediately after surgery between intraoperative cone‐beam computed tomography and postoperative computed tomography

Variable Non-pull-out group Pull-out group P-value
Patients 50 (65.8%) 26 (34.2%)  
Age, years 65.2 ±13.7 76.9 ± 12.5 P = 0.0001*
Sex
 Male 33 14  
 Female 17 12 P = 0.33
Body mass index 22.1 ± 3.7 21.8 ± 2.8 P = 0.80
Operating time, min 161.3 ± 76.8 199.3 ± 97.4 P = 0.10
Estimated blood loss, g 229.1 ± 269.4 217.9 ± 197.1 P = 0.87
Disease
 Injury 35 20 P = 0.60
 Metastasis 11 4 P = 0.56
 Spondylitis 4 2 P = 1.00
Fused segments, n 4.6 ± 1.3 5.3 ± 1.0 P = 0.0031*
Surgical procedure
 PPS 38 19  
 Open 12 7 P = 0.79
Use of a hook system 2 4 P = 0.17
Preoperative complications
 DISH 12 16 P = 0.0023*
 Osteoporosis 15 17 P = 0.0038*
 Rheumatoid arthritis 1 1 P = 1.00
 Diabetes 9 7 P = 0.39
 Asthma 6 0 P = 1.00
 Requirement for dialysis 2 1 P = 1.00
Smoking 11 1 P = 1.00
Type of rods
 Titanium 39 21  
 Cobalt chrome 11 5 P = 1.00
Screw designs
 Mixed thread 11 4  
 Dual thread 39 22 P = 1.00
Degree of sagittal alignment between the UIV and LIV (kyphotic angle)
 Intraoperative CBCT, deg 6.5 ± 24.3 5.3 ± 22.3 P = 0.81
 Postoperative CT, deg 5.9 ± 24.3 5.7 ± 22.5 P = 0.97
Alignment change in the sagittal plane from CBCT to CT, deg 2.2 ± 1.6 1.9 ± 1.3 P = 0.55
Screw density, screws/level 1.69 ± 0.24 1.70 ± 0.21 P = 0.41
  1. Data are presented as mean standard deviation or as number unless otherwise stated. CBCT cone-beam computed tomography, CT computed tomography, DISH diffuse idiopathic skeletal hyperostosis, LIV lower instrumented vertebra, PPS percutaneous pedicle screw, UIV upper instrumented vertebra. *P < 0.05