Table 1.
Baseline differences in patient demographic, comorbidity, laboratory, and procedural factors and primary outcomes by presence or absence of pelvic fixation
| With pelvic fixation (n=818), n (%) | Without pelvic fixation (n=37,595), n (%) | P | Cases available (n=38,413) | |
|---|---|---|---|---|
| Demographics | ||||
| Mean age (years)±SD | 63.6±12.4 | 61.1±13.1 | <0.001 | 38,413 |
| Obese | 401 (49.4) | 20,187 (54.0) | 0.009 | 38,213 |
| African American race | 49 (6.4) | 3034 (8.6) | 0.034 | 35,972 |
| Hispanic ethnicity | 38 (4.8) | 2012 (5.7) | 0.320 | 36,229 |
| Male gender | 315 (38.5) | 17,457 (46.4) | <0.001 | 38,402 |
| Comorbidities | ||||
| Smoker | 107 (13.1) | 7388 (19.7) | <0.001 | 38,413 |
| Dyspnea | 58 (7.1) | 2293 (6.1) | 0.242 | 38,413 |
| Diabetes mellitus | 135 (16.5) | 6993 (18.6) | 0.127 | 38,413 |
| COPD | 52 (6.4) | 1695 (4.5) | 0.012 | 38,413 |
| Heart failure | 11 (1.3 ) | 138 (0.4) | <0.001# | 38,411 |
| Hypertension | 514 (62.8) | 22,031 (58.6) | 0.015 | 38,413 |
| Disseminated cancer | 38 (4.6) | 366 (1.0) | <0.001 | 38,413 |
| Open wound infection | 24 (2.9) | 171 (0.5) | <0.001# | 38,413 |
| Chronic steroid use | 59 (7.2) | 1591 (4.2) | <0.001 | 38,413 |
| Bleeding disorder | 12 (1.5) | 607 (1.6) | 0.740 | 38,413 |
| Preoperative transfusion | 16 (2.0) | 131 (0.3) | <0.001# | 38,413 |
| ASA class ≥3 | 548 (67.0) | 19,106 (50.9) | <0.001 | 38,367 |
| Lab values, mean±SD | ||||
| Creatinine | 0.93±0.76 | 0.92±0.43 | 0.591 | 34,381 |
| White cell count | 7.43±2.62 | 7.40±2.47 | 0.687 | 35,645 |
| Hematocrit | 38.6±5.6 | 40.8±4.4 | <0.001 | 36,103 |
| Platelet | 247±78 | 247±69 | 0.862 | 35,630 |
| Procedural factors | ||||
| Length of stay, mean±SD | 7.8±7.7 | 4.3±4.6 | <0.001 | 38,386 |
| Has ALIF | 159 (19.4) | 9770 (26.0) | <0.001 | 38,413 |
| Has CAS | 165 (20.2) | 2519 (6.7) | <0.001 | 38,413 |
| Mean levels fused, mean±SD | 2.6±1.0 | 2.4±0.8 | <0.001 | 38,413 |
| Mean interbody fusions, mean±SD | 0.8±1.1 | 1.2±1.1 | <0.001 | 38,413 |
| Unadjusted primary outcomes | ||||
| Readmission | 84 (12.4) | 2130 (6.8) | <0.001 | 32,022 |
| Reoperation | 60 (7.3) | 1355 (3.6) | <0.001 | 38,413 |
| Morbidity | 465 (56.8) | 8060 (21.4) | <0.001 | 38,413 |
Readmission data is relative to 677 patients with pelvic fixation and 31,324 without. #Fisher’s exact test. Bold values indicate significance (P<0.05). ASA: American Society of Anesthesiologists, ALIF: Anterior lumbar interbody fusion, CAS: Computer-assisted surgery, COPD: Chronic obstructive pulmonary disease, SD: Standard deviation