Radiological outcomes.
| Outcome Measure | Mean ± SD | P | ||
| Total (N = 48) | Group A (N = 24) | Group B (N = 24) | ||
| Diameter of dural sac, mm2 | ||||
| Preoperative | 48.17 ± 20.05 | 41.79 ± 16.11 | 54.59 ± 25.97 | |
| Postoperative | 83.69 ± 21.80 | 73.93 ± 16.41 | 95.49 ± 29.20 | |
| Expansion ratio of dural sac, % | 195.21 ± 62.94 | 192.62 ± 49.39 | 197.74 ± 74.32 | 0.6994 |
| Ipsilateral facet joint volume, mm2 | ||||
| Preoperative | 10.09 ± 1.96 | 10.13 ± 1.98 | 10.06 ± 1.93 | |
| Postoperative | 9.26 ± 1.87 | 9.23 ± 1.88 | 9.29 ± 1.85 | |
| Preservation ratio, % | 91.01 ± 2.24 | 90.96 ± 2.88 | 92.15 ± 2.62 | 0.041 |
| Contralateral facet joint volume, mm2 | ||||
| Preoperative | 9.97 ± 2.08 | 10.07 ± 2.11 | 9.88 ± 2.05 | |
| Postoperative | 9.36 ± 2.06 | 9.47 ± 2.12 | 9.26 ± 2.00 | |
| Preservation ratio (%) | 93.63 ± 2.42 | 93.64 ± 2.61 | 93.61 ± 2.25 | 0.9443 |
| Ipsilateral lateral recess angle (°) | ||||
| Preoperative | 26.59 ± 5.04 | 27.52 ± 4.41 | 25.67 ± 5.90 | |
| Postoperative | 40.52 ± 5.24 | 40.89 ± 4.66 | 40.13 ± 5.78 | |
| Increasing ratio, % | 153.28 ± 20.27 | 150.38 ± 15.91 | 156.11 ± 23.62 | 0.1777 |
| Contralateral lateral recess angle, (°) | ||||
| Preoperative | 27.75 ± 4.66 | 28.57 ± 3.96 | 26.93 ± 5.38 | |
| Postoperative | 43.76 ± 4.82 | 43.87 ± 3.95 | 43.66 ± 5.84 | |
| Increasing ratio, % | 160.36 ± 19.87 | 155.22 ± 15.99 | 165.39 ± 22.07 | 0.0136 |
Abbreviation: BESS, biportal endoscopic spine surgery.
Note: Group A underwent conventional BESS technique. Group B underwent both-facet joint–preserving BESS technique. P < 0.05 was considered a statistically significant difference.