Article Figures & Data
Figures
- Figure 1
Illustration of positive (A), neural (B), and negative (C) upper instrumented vertebrae (UIV) tilt angle.
- Figure 2
Illustration of positive (A), neural (B), and negative (C) upper instrumented vertebrae (UIV) screw angle.
- Figure 3
Distribution of upper instrumented vertebrae (UIV) tilt angle (A) and UIV screw angle (B). Abbreviation: IQR, interquartile range.
- Figure 4
Distribution of upper instrumented vertebrae (UIV) tilt angle (A) and UIV screw angle (B) with proximal junctional kyphosis (PJK) occurrence.
Tables
- Table 1
Demographics, operative variables, radiographic measurements, and PROMs of the total cohort.
Variables N = 117 Age, y, mean ± SD 65.6 ± 9.2 Women, n (%) 92 (78.6) Body mass index, mean ± SD 30.0 ± 6.4 Charlson Comorbidity Index, mean ± SD 2.1 ± 2.8 Comorbidities, n (%) Diabetes 28 (23.9) Chronic obstructive pulmonary disease 37 (31.6) Congestive heart failure 13 (11.1) Hypertension 88 (75.2) Osteopenia/osteoporosis 47 (40.1) Dependent 15 (12.8) Hounsfield unit average, mean ± SD 151.3 ± 53.4 Prior fusion, n (%) 46 (39.3) Fused to sacrum, n (%) 111 (94.9) Total instrumented levels, mean ± SD 8.9 ± 1.7 Three-column osteotomy, n (%) 21 (18.0%) Sagittal malalignment (SVA > 5 cm), n (%) 56 (47.8%) Coronal malalignment (CVA > 3 cm), n (%) 21 (17.9%) Neutral alignment, n (%) 22 (18.8%) Mixed malalignment, n (%) 18 (15.3%) Upper instrumented vertebra, n (%) T7 9 (7.7) T8 19 (16.2) T9 12 (10.3) T10 33 (28.2) T11 20 (17.1) T12 15 (12.8) L1 4 (3.4) L2 5 (4.3) Preoperative radiographic measurements, mean ± SD Pelvic incidence 51.6 ± 10.8 Pelvic tilt 25.9 ± 8.9 Thoracic kyphosis 32.3 ± 15.8 SVA 88.0 ± 73.5 CVA 23.9 ± 25.2 Pelvic incidence lumbar lordosis mismatch 21.9 ± 16.5 L1–S1 lordosis 29.7 ± 18.0 L4–S1 lordosis 27.9 ± 12.1 Lordosis distribution index 96.0 ± 158.6 Preoperative PROMs, mean ± SD NRS-Back 7.3 ± 1.7 NRS-Leg 6.3 ± 2.4 Oswestry Disability Index 51.6 ± 11.5 EQ-5D 0.485 ± 0.204 Abbreviations: CVA, coronal vertical axis; NRS, Numeric Rating Scale; PROM, patient-reported outcome measure; SVA, sagittal vertical axis.
Outcomes Total Sample
N = 117Complications, n (%) Mechanical complications 70 (59.8) Proximal junctional kyphosis 41 (35.0) Proximal junctional failure 26 (22.2) Rod fracture/pseudarthrosis 46 (39.3) Distal junctional kyphosis 1 (0.9) Implant related 8 (6.8) Reoperations 54 (46.2) Postoperative radiographic measurements, mean ± SD Pelvic tilt 23.9 ± 9.2 Thoracic kyphosis 40.9 ± 14.4 Sagittal vertical axis 66.3 ± 58.4 Coronal vertical axis 19.2 ± 17.5 Pelvic incidence lumbar lordosis mismatch 11.3 ± 14.2 L1–S1 lordosis 40.3 ± 14.4 L4–S1 lordosis 26.9 ± 9.1 Lordosis distribution index 70.1 ± 29.1 Sagittal vertical axis correction 47.9 ± 41.97 Coronal vertical axis correction 29.2 ± 30.8 Patient-reported outcome measures, n (%) MCID NRS-Back 47 (51.1) MCID NRS-Leg 59 (68.6) MCID Oswestry Disability Index 51 (55.4) Abbreviations: MCID, minimal clinically important difference; NRS, Numeric Rating Scale.
- Table 3
Comparison of the UIV tilt angle and UIV screw angle in patients with and without proximal junctional kyphosis.
Variables With PJK Without PJK P UIV tilt angle Mean ± SD 13.6° ± 14.1° 12.5° ± 13.4° 0.689 Lordotic UIV tilt angle, n (%) 34 (36.9) 58 (63.1) 0.405 Neutral/kyphotic UIV tilt angle, n (%) 7 (28.0) 18 (72.0) UIV screw angle Mean ± SD –0.4° ± 7.9° –4.7° ± 7.7° 0.005 Cranially directed screws, n (%) (N = 32) 17 (53.1) 15 (46.9) 0.012 Neutral/caudally directed screws, n (%) (N = 85) 24 (28.2) 61 (71.8) Abbreviation: UIV, upper instrumented vertebrae.
- Table 4
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.
In this issue
Jump to section
Related Articles
Cited By...
- No citing articles found.