Univariate and multivariable drivers of cost.
| Independent Variables | Univariate Analysis (P) | Multivariable Cost Analysis | |||
| ACDF | Foraminotomy | All | β (±95% CI) | P | |
| Preoperative variables | |||||
| BMI | 0.243 | 0.801 | 0.549 | - | - |
| Age | 0.091 | 0.006 | <0.001 | - | - |
| Race (white) | 0.505 | 0.072 | 0.211 | - | |
| Gender | 0.675 | 0.559 | 0.049 | - | - |
| Insurance (private) | 0.529 | 0.026 | 0.297 | - | - |
| Operative variables | |||||
| LOS (nights) | 0.604 | - | <0.001 | - | - |
| Operative minutes | 0.427 | 0.122 | <0.001 | - | - |
| Surgical procedure | |||||
| ACDF | - | - | <0.001 | $17,723 ± $3065 | <0.001 |
| Endoscopic (reference) | - | - | - | $10,103 ± $2537 | <0.001 |
Abbreviations: ACDF, anterior cervical discectomy and fusion; BMI, body mass index; LOS, length of stay.
Note: Univariate analysis performed with 2-tailed t test for binary independent variables and simple linear regression for independent continuous variables with a cutoff at alpha = 0.2. Multivariable stepwise regression including any significant univariate variables was performed with a significance cutoff at alpha < 0.05. Boldface indicates statistically significant findings.