Covariate distributions prior to the propensity score match, after the match, as well as in the remaining unmatched CONCORDE Bullet treated patients
| Covariate | Total study population | After propensity match | Unmatched exposures | |||||
| CONCORDE Bullet | Alternate IVBI | CONCORDE Bullet | Alternate IVBI | CONCORDE Bullet | ||||
| (N=136) | (N=98) | Std. diff | (N=69) | (N=69) | Std. diff | (N=67) | Std. diff | |
| Female | 52.94% | 52.04% | 0.018 | 50.72% | 55.07% | 0.087 | 55.22% | 0.090 |
| Age—median (IQR) | 61.84±12.43 | 58.87±13.16 | 0.232 | 60.32±13.30 | 60.09±13.88 | 0.017 | 63.40±11.36 | 0.249 |
| Body mass index—median (IQR) | 30.03±5.69 | 29.29±5.80 | 0.130 | 29.86±5.52 | 29.75±6.13 | 0.017 | 30.21±5.89 | 0.062 |
| Diabetes | 13.97% | 10.20% | 0.116 | 14.49% | 10.14% | 0.133 | 13.43% | 0.031 |
| Heart failure | 0.74% | 1.02% | 0.031 | 1.45% | 1.45% | 0.000 | 0.00% | – |
| Coronary artery disease | 4.41% | 4.08% | 0.016 | 4.35% | 4.35% | 0.000 | 4.48% | 0.006 |
| Smoker (active) | 13.24% | 8.16% | 0.165 | 8.70% | 8.70% | 0.000 | 17.91% | 0.274 |
| Preoperative opioid Rx | 19.12% | 27.55% | 0.200 | 24.64% | 18.84% | 0.141 | 13.43% | 0.288 |
| ASA class 1–2 | 68.38% | 72.45% | 0.089 | 66.67% | 75.36% | 0.193 | 70.15% | 0.075 |
| ASA class 3–5 | 31.62% | 27.55% | 0.089 | 33.33% | 24.64% | 0.193 | 29.85% | 0.075 |
| Prior spine surgery | 0.74% | 0.00% | – | 0.00% | 0.00% | – | 1.49% | – |
| Single-level | 40.44% | 44.90% | 0.090 | 57.97% | 55.07% | 0.059 | 22.39% | 0.779 |
| Two-level | 0.00% | 1.02% | – | 0.00% | 0.00% | – | 0.00% | – |
| Complex repair (>2 levels) | 40.44% | 6.12% | 0.889 | 7.25% | 8.70% | 0.054 | 74.63% | 1.881 |
| No level identified | 19.12% | 47.96% | 0.642 | 34.78% | 36.23% | 0.030 | 2.99% | 0.889 |
| Surgeon volume low | 5.15% | 27.55% | 0.636 | 8.70% | 11.59% | 0.096 | 1.49% | 0.332 |
| Surgeon volume medium | 72.79% | 64.29% | 0.184 | 75.36% | 76.81% | 0.034 | 70.15% | 0.117 |
| Surgeon volume high | 22.06% | 8.16% | 0.396 | 15.94% | 11.59% | 0.126 | 28.36% | 0.302 |
ASA class, American Society of Anesthesiology physical status classification; IVBI, intervertebral body implant; Std. diff, standard difference.