Table 5. Subsidence risk factors.
| Subsidence (N=7) | No Subsidence (N=85) | t, χ2 | P | |
|---|---|---|---|---|
| Age (years) | 62.4±9.2 | 57.7±12.6 | 0.97 | 0.336 |
| Gender | ||||
| Female | 4 (57.1) | 38 (44.7) | 0.4 | 0.698 |
| BMI | 28.5 | 27.3 | 0.58 | 0.562 |
| Charlson comorbidity index | 2.0±1.2 | 2.0±1.6 | 0.02 | 0.984 |
| Current smoker | 0 | 6 (7.1) | 0.53 | 1 |
| Preoperative diagnosis | ||||
| Spondylolisthesis | 6 (85.7) | 38 (44.7) | 4.49 | 0.61 |
| Degenerative disk disease | 1 (14.3) | 32 (37.6) | ||
| Isthmic spondylolisthesis | 0 | 7 (8.2) | ||
| Spondylolisthesis/DDD | 0 | 3 (3.5) | ||
| ASD/Spondylolisthesis | 0 | 2 (3.5) | ||
| Pseudoarthrosis | 0 | 1 (1.2) | ||
| Spondylosis/RDH | 0 | 2 (2.4) | ||
| Surgical level | ||||
| L3–4 | 0 | 5 (5.9) | 3.68 | 0.159 |
| L4–5 | 5 (71.4) | 30 (35.3) | ||
| L5–S1 | 2 (28.6) | 50 (58.8) | ||
| PEEK interbody cage | 6 (85.7) | 67 (78.8) | 0.19 | 1 |
| BMP | 0 | 14 (16.5) | 1.36 | 0.59 |
| Implant lordosis (°) | 9.9 | 11.8 | 1.45 | 0.15 |
| Pelvic incidence (°) | 60.3 | 57.3 | 0.65 | 0.52 |
| Lumbar lordosis (°) | ||||
| Pre-op | 49.7 | 51.9 | 0.39 | 0.699 |
| Post-op | 53 | 54.5 | 0.28 | 0.777 |
DDD, degenerative disk disease; ASD, adjacent segment disease; RDH, recurrent disk herniation; BMP, bone morphogenetic protein.