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.