Table 2.
Baseline characteristics determined by preoperative magnetic resonance imaging and intraoperative findings
| Early group (n = 20) |
Late group (n = 62) |
OR or difference | 95% CI | P value | |
|---|---|---|---|---|---|
| Surgical level, L3-4/L4-5/L5-S1 | 2/8/10 | 4/14/44 | 0.111† | ||
| Pfirmann grade, I/II/III/IV | 0/4/12/3 | 0/18/38/7 | 0.763† | ||
| High intensity zone | 6 (30.0%) | 22 (35.5%) | 1.436 | 0.391–5.269 | 0.585‡ |
| Morphology of disc, bulging/protruded/extruded | 2/11/9 | 8/35/17 | 0.130† | ||
| Location of herniation, central/right/left | 6/7/7 | 20/13/29 | 0.092† | ||
| Degree of canal compromise, mild/moderate/severe | 13/7/0 | 43/15/0 | 0.208† | ||
| Degree of nerve compression, abutting/displace/near obliteration/obliteration | 8/7/4/1 | 34/21/6/1 | 0.264† | ||
| Herniated disc volume (mm3) | 0.31 ± 0.11 | 0.30 ± 0.14 | 0.01 ± 0.04 | − 0.08–0.09 | 0.898‡ |
| Degree of stenosis, none/mild/moderate/severe | 12/7/1/0 | 42/19/1/0 | 0.450† | ||
| Intraoperative adhesion, mild/moderate/severe | 2/2/16 | 3/20/29 | 0.249† |
CI confidence interval, OR odds ratio
†Pearson’s Chi square test, ‡independent t-test