Article Figures & Data
Figures
- Figure
Example pre- and postoperative lateral x-ray images for each group.
Tables
Characteristic Maintained (n = 177) Restored (n = 101) Kyphotic (n = 30) P Valuea,b Age 57.0 (59.5, 65.0) 57.0 (49.0, 63.0) 52.5 (45.5, 68.7) 0.18 Sex 0.02 Female 86 (48.6%) 39 (38.6%) 20 (66.7%) Male 91 (51.4%) 62 (61.4%) 10 (33.3%) Body mass index 28.7 (25.6, 32.6) 29.5 (27.1, 34.7) 27.7 (24.9, 31.4) 0.07 Smoking status 0.59 Never smoker 117 (66.1%) 64 (63.4%) 23 (76.7%) Former smoker 39 (22.0%) 27 (26.7%) 6 (20.0%) Current smoker 21 (11.9%) 10 (9.9%) 1 (3.3%) Charlson Comorbidity Index 2.0 (1.0, 3.0) 2.0 (1.0, 3.0) 1.0 (0.7, 2.0) 0.17 Preoperative diagnosis 0.52 Radiculopathy 90 (50.8%) 49 (48.5%) 19 (63.4%) Myelopathy 73 (41.2%) 46 (45.5%) 10 (33.3%) Myeloradiculopathy 14 (7.9%) 6 (5.9%) 1 (3.3%) Levels fused 0.28 1 58 (32.8%) 35 (34.7%) 8 (26.7%) 2 58 (32.8%) 42 (41.6%) 10 (33.3%) 3 61 (34.5%) 24 (23.8%) 12 (40.0%) Preoperative C2-C7 Cobb angle 8.9 (7.5, 9.7) −5.6 (−6.5, −4.8) −7.2 (−9.0, −5.4) <0.001 Postoperative C2-C7 Cobb angle 12.3 (13.3, 11.2) 8.2 (4.6, 13.8) −6.2 (−8.5, −5.2) <0.001 Follow-up 14.6 (12.1, 18.3) 14.8 (12.6, 19.5) 16.2 (12.0, 21.1) 0.28 - Table 2
Health-related quality-of-life outcomes stratified by postoperative correction of cervical lordosis.
Outcome Measure Maintained
(n = 177)Restored
(n = 101)Kyphotic
(n = 30)P Valuea Physical component of short form-12 Preoperative 32.6 (30.2, 35.0) 35.5 (32.0, 39.0) 35.0 (28.1, 41.9) 0.32 Postoperative 41.6 (38.4, 44.8) 45.8 (41.9, 49.6) 36.6 (29.1, 44.1) 0.02 Delta 9.0 (5.4, 12.6) 10.3 (7.0, 13.5) 1.5 (−7.8, 10.8) 0.04 P value <0.001 <0.001 0.01 Mental component of short form-12 Preoperative 49.0 (45.3, 52.7) 46.7 (43.0, 50.3) 49.1 (41.7, 56.5) 0.86 Postoperative 50.8 (47.2, 54.3) 45.2 (38.8, 51.6) 51.4 (43.5, 59.3) 0.73 Delta 1.8 (−2.8, 6.3) −1.4 (−7.7, 4.9) 2.3 (−5.8, 10.3) 0.68 P value 0.04 0.22 0.07 Neck Disability Index Preoperative 36.8 (31.6, 42.0) 43.0 (34.7, 51.4) 35.6 (28.8, 42.4) 0.65 Postoperative 23.8 (17.6, 30.2) 28.0 (18.2, 37.8) 17.4 (8.8, 26.0) 0.65 Delta −13.0 (−19.8, −6.1) −14.8 (−27.0, −2.6) −18.2 (−25.8, −10.5) 0.89 P value <0.001 <0.001 0.002 VAS arm Preoperative 3.3 (2.1, 4.4) 5.3 (3.8, 6.8) 2.8 (0.9, 4.9) 0.02 Postoperative 2.3 (1.3, 3.3) 1.5 (0.6, 2.4) 2.3 (0.6, 4.1) 0.93 Delta −0.9 (−2.0, 0.1) −3.8 (−5.1, −2.6) −0.6 (−2.8, 1.5) 0.03 P value <0.001 <0.001 0.01 VAS neck Preoperative 5.1 (4.1, 6.1) 5.3 (4.0, 6.6) 6.4 (5.4, 7.3) 0.31 Postoperative 2.2 (1.3, 3.1) 2.0 (0.7, 3.2) 3.5 (1.0, 6.1) 0.23 Delta −2.9 (−4.3, −1.5) −3.3 (−5.0, −1.7) −2.8 (−5.2, −0.4) 0.26 P value <0.001 <0.001 0.002 Abbreviation: VAS, visual analog scale.
Note: Significance achieved at P < 0.05.
↵a Multiple linear regression analysis was done between groups controlling for age, body mass index, Charlson Comorbidity Index, and preoperative diagnosis.
- Table 3
Regression analysis comparing correction of cervical lordosis and health-related quality-of-life outcomes.
Outcome Measure β Coefficient 95% CI P Valuea Physical component of short form-12 Maintained : restored −1.5 (−5.8, 2.7) 0.19 Restored : kyphotic 8.6 (3.9, 13.3) 0.03 Maintained : kyphotic 4.2 (−0.7, 9.1) 0.17 Mental component of short form-12 Maintained : restored 1.1 (−2.9, 5.0) 0.50 Restored : kyphotic −3.2 (−9.7, 3.4) 0.54 Maintained : kyphotic −2.2 (−8.5, 3.9) 0.76 Neck Disability Index Maintained : restored 1.7 (−8.6, 5.2) 0.71 Restored : kyphotic 5.6 (−5.8, 17.2) 0.82 Maintained : kyphotic 7.6 (−3.2, 18.5) 0.62 VAS arm Maintained : restored 1.9 (−0.1, 2.9) 0.27 Restored : kyphotic −2.0 (−3.7, −0.4) 0.03 Maintained : kyphotic −1.2 (−2.7, 0.4) 0.11 VAS neck Maintained : restored 0.3 (−1.4, 1.9) 0.22 Restored : kyphotic −0.5 (−1.5, 0.5) 0.12 Maintained : kyphotic −0.8 (−2.3, 0.8) 0.33 Abbreviation: VAS, visual analog scale.
Note: Significance achieved at P < 0.05.
↵a Regression analysis controlled for age, body mass index, Charlson Comorbidity Index, and preoperative diagnosis.
- Table 4
Health-related quality-of-life outcomes in patients with preoperative cervical lordosis less than 0° (kyphotic).
Outcome Measure 1-Level
(n = 43)2-Level
(n = 51)3-Level
(n = 36)P Value Regression Analysisa Physical component of short form-12 Preoperative 34.4(31.1, 37.8 36.0 (33.0, 38.9) 34.4 (31.4, 37.3) 0.87 β: 0.03 (−1.96, 2.02) P = 0.98 Postoperative 42.4 (39.2, 45.7) 42.4 (39.3, 45.5) 42.4 (39.6, 45.2) 0.95 Delta 7.8 (5.5, 10.0) 7.9 (5.5, 10.3) 7.5 (4.0, 11.0) 0.99 P value <0.001 <0.001 <0.001 Mental component of short form-12 Preoperative 50.5 (47.2, 53.7) 50.8 (47.8, 53.8) 48.1 (44.3, 51.9) 0.52 β: 1.06 (−2.04, 4.16) P = 0.50 Postoperative 51.9 (48.5, 55.4) 49.9 (46.3, 53.5) 52.6 (49.0, 56.3) 0.53 Delta 1.5 (−1.9, 5.0) 0.8 (−3.6, 5.1) 3.9 (−1.3, 9.0) 0.65 P value 0.35 0.55 0.08 Neck Disability Index Preoperative 39.7 (32.8, 46.5) 33.4 (27.7, 39.1) 38.4 (33.1, 43.8) 0.37 β: 0.76 (−7.89, 9.41) P = 0.86 Postoperative 35.8 (15.6, 56.0) 22.3 (15.3, 29.4) 23.3 (16.2, 30.3) 0.39 Delta −15.5 (−29.1, −2.0) −16.7 (−28.6, −4.9) −15.6 (−27.1, −4.0) 0.52 P value 0.01 0.01 0.001 VAS arm Preoperative 4.6 (3.7, 5.5) 5.0 (4.1, 5.9) 4.2 (2.6, 5.8) 0.62 β: 0.37 (−0.40, 1.14) P = 0.34 Postoperative 2.4 (1.5, 3.2) 2.5 (1.8, 3.3) 1.8 (1.0, 2.6) 0.33 Delta −3.1 (−3.9, −2.4) −3.1 (−4.1, −2.2) −2.4 (−4.2, −0.7) 0.60 P value <0.001 <0.001 0.01 VAS neck Preoperative 4.5 (3.5, 5.4) 5.0 (3.9, 6.1) 5.8 (4.7, 7.0) 0.29 β: 0.31 (−0.61, 1.23) P = 0.50 Postoperative 1.5 (0.7, 2.2) 1.6 (0.8, 2.4) 3.0 (1.8, 4.2) 0.01 Delta −3.4 (−4.5, −2.2) −3.1 (−4.2, −2.0) −2.7 (−4.4, −0.9) 0.76 P value <0.001 <0.001 0.01 Abbreviation: VAS, visual analog scale.
Note: Significance achieved at P < 0.05.
↵a Regression analysis controlled for age, body mass index, Charlson Comorbidity Index, and preoperative diagnosis.
- Table 5
Health-related quality-of-life outcomes in patients with preoperative cervical lordosis between 0° and 10° (neutral).
Outcome Measure 1-Level
(n = 40)2-Level
(n = 42)3-Level
(n = 32)P Value Regression Analysisa Physical component of short form-12 Preoperative 34.5 (30.6, 38.4) 32.7 (30.4, 35.0) 35.2 (32.2, 38.1) 0.43 β: −2.91 (−6.26, 0.43) P = 0.09 Postoperative 44.8 (41.0, 48.6) 39.1 (35.9, 42.2) 38.8 (35.7, 42.0) 0.02 Delta 11.3 (5.8, 16.7) 6.8 (3.2, 10.5) 5.1 (1.3, 8.9) 0.16 P value <0.001 0.001 0.02 Mental component of short form-12 Preoperative 49.3 (44.4, 54.1) 52.6 (48.7, 56.5) 49.8 (45.7, 53.9) 0.27 β: −0.02 (−3.86, 3.83) P = 0.99 Postoperative 52.3 (48.1, 56.4) 52.2 (49.0, 55.4) 50.0 (45.7, 54.3) 0.40 Delta 2.3 (−3.6, 8.3) 0.2 (−3.1, 3.4) 2.4 (−4.1, 9.1) 0.84 P value 0.49 0.85 0.76 Neck Disability Index Preoperative 44.2 (36.6, 51.8) 43.4 (36.5, 50.3) 34.7 (29.4, 40.0) 0.11 β: 3.40 (−2.81, 9.60) P = 0.27 Postoperative 26.5 (6.1, 47.0) 52.4 (15.2, 79.3) 22.6 (17.0, 28.2) 0.09 Delta −23.6 (−34.9, −12.3) −14.9 (−55.5, 25.8) −14.2 (−20.1, −8.2) 0.35 P value 0.027 0.29 <0.001 VAS arm Preoperative 4.7 (3.7, 5.7) 6.1 (5.2, 7.1) 2.5 (1.1, 3.9) <0.001 β: 0.50 (−0.47, 1.47) P = 0.31 Postoperative 2.4 (1.4, 3.5) 3.2 (2.0, 4.4) 2.4 (1.4, 3.5) 0.56 Delta −2.5 (−3.6, −1.4) −4.2 (−5.4, −2.9) −0.9 (−2.4, 0.5) 0.003 P value 0.001 <0.001 0.55 VAS neck Preoperative 4.8 (3.7, 5.9) 6.5 (5.4, 7.4) 4.8 (3.3, 6.2) 0.10 β: 0.43 (−0.59, 1.45) P = 0.40 Postoperative 0.9 (0.3, 1.6) 1.7 (0.7, 2.7) 2.9 (1.8, 4.0) 0.001 Delta −3.9 (−5.1, −2.8) −5.2 (−6.5, −3.9) −2.5 (−4.2, −0.7) 0.03 P value <0.001 <0.001 0.07 Abbreviation: VAS, visual analog scale.
Note: Significance achieved at P < 0.05.
↵a Regression analysis controlled for age, body mass index, Charlson Comorbidity Index, and preoperative diagnosis.
- Table 6
Health-related quality-of-life outcomes in patients with preoperative cervical lordosis greater than 10° (lordotic).
Outcome Measure 1-Level
(n = 18)2-Level
(n = 17)3-Level
(n = 29)P Value Regression Analysisa Physical component of short form-12 Preoperative 33.6 (28.7, 38.5) 31.5 (28.3, 34.8) 30.1 (25.2, 34.9) 0.78 β: 2.09 (−2.56, 6.75) P = 0.37 Postoperative 37.0 (30.5, 43.6) 40.9 (35.8, 45.9) 36.9 (32.3, 41.5) 0.47 Delta 3.6 (−2.2, 9.4) 8.7 (2.8, 14.6) 6.0 (−0.5, 12.5) 0.57 P value 0.20 0.01 0.01 Mental component of short form-12 Preoperative 48.1 (42.2, 54.1) 49.3 (44.6, 54.0) 47.1 (40.5, 53.6) 0.96 β: −1.14 (−6.15, 3.87) P = 0.65 Postoperative 53.0 (47.5, 58.5) 56.4 (51.9, 60.9) 50.7 (46.3, 55.1) 0.15 Delta 3.6 (−5.0, 12.2) 6.4 (0.3, 12.6) 4.1 (−1.7, 9.8) 0.64 P value 0.40 0.04 0.31 Neck Disability Index Preoperative 41.1 (28.3, 53.9) 34.4 (26.0, 42.7) 34.2 (27.5, 40.9) 0.64 β: 5.14 (−12.21, 22.49) P = 0.53 Postoperative 18.5 (−24.1, 61.1) 19.0 (0.4, 45.7) 26.2 (16.6, 35.7) 0.62 Delta −21.3 (−49.6, 6.9) −19.0 (−41.0, −0.2) −7.9 (−25.6, 9.8) 0.70 P value 0.11 0.18 0.02 VAS arm Preoperative 6.4 (4.8, 7.6) 6.7 (5.6, 7.7) 2.9 (1.1, 4.9) 0.01 β: 0.99 (−0.44, 2.42) P = 0.17 Postoperative 2.7 (1.3, 4.0) 2.2 (0.6, 3.8) 1.7 (0.5, 2.9) 0.20 Delta −4.2 (–5.8, –2.6) –5.5 (–7.4, –3.7) –1.3 (–3.6, 0.7) 0.01 P value 0.003 0.02 0.58 VAS neck Preoperative 6.1 (4.5, 7.8) 5.7 (3.7, 7.8) 4.8 (3.1, 6.5) 0.29 β: 0.79 (−0.78, 2.36) P = 0.31 Postoperative 0.6 (−0.1, 1.3) 1.0 (−0.1, 2.1) 2.2 (1.1, 3.4) 0.04 Delta –5.5 (–7.1, –3.8) –5.7 (–7.8, –3.5) –2.6 (–5.1, –0.1) 0.07 P value 0.003 0.03 0.02 Abbreviation: VAS, Visual Analog Scale.
Note: Significance achieved at P < 0.05.
↵a Regression analysis controlled for age, body mass index, Charlson Comorbidity Index, and preoperative diagnosis.
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