Significant predictors of operative duration obtained from multivariate regression analysis.
| Parameter | Regression Coefficient | Standardized Coefficient (β) | 95% CI | P value |
| Experience of the chief surgeon | −22.3 | −0.36 | −32.39)−(to −12.23 | <0.0001 |
| Cobb angle of the major structural curve | 1.5 | 0.35 | 0.61–2.52 | 0.001 |
| Number of screws inserted | 6.2 | 0.28 | 2.21–10.45 | 0.002 |
| C-DAR | 2.2 | 0.20 | 0.24–4.62 | 0.045 |
| Apical vertebral rotation (Nash and Moe Grade)a | ||||
| 2 | −32.2 | −0.21 | −78.2 to 12.4 | 0.10 |
| 3 | 5.3 | 0.03 | −42.9 to 53.2 | 0.08 |
| 4 | 6.4 | 0.03 | −46.4 to 60.2 | 0.08 |
↵Final model: n = 150; R 2 = 0.44; P < 0.0001.
a Nash and Moe Grade 1 was taken as a reference.
C-DAR = coronal deformity angular ratio; CI = confidence interval.