Univariate and multivariable logistic regression predicting PJK. Multivariable regression model included age, body mass index, osteopenia/osteoporosis, postoperative sagittal vertical axis, postoperative pelvic incidence lumbar lordosis, UIV tilt angle, and UIV screw angle.
| Variable | Univariate | Multivariable | ||||
| OR (95% CI) | Wald-df | P | OR (95% CI) | Wald-df | P | |
| Mechanical Complications | ||||||
| UIV tilt angle | 0.99 (0.96–1.02) | –0.76 | 0.621 | 1.01 (0.97–1.05) | –0.31 | 0.405 |
| UIV screw angle | 1.01 (0.96–1.06) | –0.64 | 0.545 | 1.06 (0.98–1.15) | 1.70 | 0.100 |
| PJK | ||||||
| UIV tilt angle | 1.00 (0.97–1.03) | –0.85 | 0.686 | 1.06 (1.01–1.12) | 4.42 | 0.020 |
| UIV screw angle | 1.07 (1.01–1.12) | 6.23 | 0.007 | 1.19 (1.07–1.33) | 9.40 | 0.001 |
| PJK | ||||||
| UIV tilt angle | 1.00 (0.97–1.03) | –0.97 | 0.846 | 1.06 (1.01–1.12) | 2.86 | 0.049 |
| UIV screw angle | 1.07 (1.01–1.14) | 5.44 | 0.011 | 1.14 (1.02–1.27) | 5.13 | 0.013 |
| Rod Fracture/Pseudarthrosis | ||||||
| UIV tilt angle | 0.98 (0.96–1.02) | –0.33 | 0.412 | 0.99 (0.95–1.03) | –0.93 | 0.785 |
| UIV screw angle | 0.97 (0.93–1.02) | –0.06 | 0.334 | 0.95 (0.89–1.02) | 0.58 | 0.208 |
| Implant Related | ||||||
| UIV tilt angle | 1.00 (0.95–1.05) | –0.99 | 0.926 | 1.03 (0.95–1.12) | –0.39 | 0.435 |
| UIV screw angle | 0.96 (0.88–1.06) | –0.46 | 0.466 | 0.97 (0.82–1.15) | –0.91 | 0.768 |
| Reoperations | ||||||
| UIV tilt angle | 0.98 (0.96–1.01) | –0.38 | 0.430 | 1.00 (0.96–1.04) | –0.95 | 0.831 |
| UIV screw angle | 0.99 (0.95–1.04) | –0.99 | 0.962 | 0.99 (0.92–1.06) | –0.93 | 0.785 |
| MCID NRS-Back | ||||||
| UIV tilt angle | 0.98 (0.96–1.01) | –0.50 | 0.480 | 0.96 (0.92–1.01) | 1.13 | 0.144 |
| UIV screw angle | 1.04 (0.99–1.10) | 1.60 | 0.106 | 1.08 (0.99–1.18) | 2.11 | 0.077 |
| MCID NRS-Leg | ||||||
| UIV tilt angle | 0.99 (0.96–1.03) | –0.99 | 0.959 | 0.99 (0.94–1.03) | –0.82 | 0.671 |
| UIV screw angle | 1.02 (0.97–1.09) | –0.08 | 0.337 | 1.01 (0.92–1.10) | –0.97 | 0.859 |
| MCID Oswestry Disability Index | ||||||
| UIV tilt angle | 1.00 (0.97–1.03) | 0.09 | 0.753 | 1.01 (0.96–1.04) | –1.00 | 0.961 |
| UIV screw angle | 1.02 (0.97–1.07) | –0.24 | 0.384 | 1.05 (0.96–1.14) | 0.45 | 0.228 |
Abbreviations: MCID, minimal clinically important difference; NRS, Numeric Rating Scale; PJK, proximal junctional kyphosis; UIV, upper instrumented vertebrae.
Note. UIV tilt angle and UIV screw angle were treated as continuous variables.