Patient demographics and preoperative clinical scores (n = 103).
| Early (n = 42) | Late (n = 61) | ||||
| Mean | SD | Mean | SD | P Value | |
| Age, y | 53.0 | 7.7 | 53.0 | 10.3 | 0.975 |
| Gender, % | |||||
| Male | 64.3 | 70.5 | 0.507 | ||
| Female | 35.7 | 29.5 | |||
| BMI | 24.9 | 4.5 | 25.3 | 4.3 | 0.632 |
| Smoking status, % | |||||
| Never | 69.0 | 57.4 | |||
| Former | 16.7 | 13.1 | 0.198 | ||
| Current | 14.3 | 29.5 | |||
| Comorbidities, % | |||||
| Diabetes | 14.3 | 16.4 | 0.772 | ||
| Hypertension | 26.2 | 41.0 | 0.122 | ||
| Hyperlipidemia | 14.3 | 32.8 | 0.039 | ||
| Heart disease | 7.1 | 4.9 | 0.636 | ||
| Stroke | 0.0 | 1.6 | 0.404 | ||
| Kidney disease | 0.0 | 1.6 | 0.404 | ||
| Asthma | 2.4 | 3.3 | 0.790 | ||
| Osteoarthritis | 14.3 | 4.9 | 0.098 | ||
| Depression | 0.0 | 0.0 | 1.000 | ||
| No comorbidities | 45.2 | 34.4 | 0.269 | ||
| No. of levels, % | |||||
| 1 | 52.4 | 42.6 | 0.329 | ||
| 2 | 47.6 | 57.4 | |||
| Length of Op, mins | 127.8 | 30.1 | 135.2 | 44.0 | 0.392 |
| Length of stay, d | 2.9 | 1.6 | 3.3 | 2.4 | 0.397 |
| Time taken to RTW, d | 34.7 | 15.1 | 134.9 | 123.9 | <0.001 |
| Preop VAS NPa | 2.9 | 3.2 | 4.0 | 3.2 | 0.089 |
| Preop VAS APa | 2.6 | 3.3 | 2.9 | 3.3 | 0.678 |
| Preop JOA | 12.8 | 2.4 | 11.4 | 3.1 | 0.015 |
| Preop NSa | 44.3 | 23.3 | 48.0 | 27.3 | 0.469 |
| Preop NPDa | 24.8 | 17.5 | 36.6 | 21.6 | 0.004 |
| Preop NDIa | 21.2 | 16.2 | 33.4 | 19.9 | 0.001 |
| Preop PCS | 40.2 | 11.2 | 35.7 | 13.1 | 0.071 |
| Preop MCS | 47.7 | 11.3 | 46.1 | 12.4 | 0.499 |
aA lower score is better.
BMI, body mass index; JOA, Japanese Orthopaedic Association; MCS, Mental Component Summary; NDI, Neck Disability Index; NPD, neck pain and disability; NS, neurogenic symptoms; PCS, Physical Component Summary; RTW, return to work; VAS AM, visual analog scale arm pain; VAS NP, visual analog scale neck pain.