Summary of Study Population Characteristics: Total Disc Replacement (TDR) and Fusion Groups
| TDR | Fusion | |
|---|---|---|
| General | ||
| Gender | ||
| Male | 55.9% | 46.7% |
| Female | 44.1% | 53.3% |
| Mean age, years | 41.1 | 41.2 |
| Mean body mass index (kg/m2) | 27.0 | 27.0 |
| Pain duration | ||
| < 1 year | 13.4% | 10.0% |
| > 1 year | 86.6% | 90.0% |
| Previous nonfusion spinal surgery | 37.0% | 23.3% |
| Smoker | 32.3% | 43.3% |
| Surgical | ||
| Number of levels operated | ||
| 1 level | 60.6% | 53.3% |
| 2 levels | 39.4% | 46.7% |
| Level(s) operated | ||
| L3–L4 | 3.3% | 3.3% |
| L4–L5 | 18.1% | 6.7% |
| L5–S1 | 38.6% | 43.3% |
| L3–L4 and L4–L5 | 3.1% | 6.7% |
| L4–5 and L5–S1 | 36.9% | 40.0% |
Note. No significant differences were observed (all Ps > .05).