Summary of findings.
| Outcomes | Primary Analysis | RCT Subgroup | Grade I Spondylolisthesis | Single-Vertebral Level Surgery |
| Oswestry Disability Index | MD 4.04 [0.95, 7.13], P = 0.01; I 2: 80% | MD 1.78 [−10.34, 13.91], P = 0.77; I 2: 80% | MD 6.48 [1.17, 11.79], P < 0.001; I 2: 72% | MD 4.15 [1.48, 6.82], P = 0.002; I 2: 0% |
| MCID ODI | OR 0.76 [0.57, 1.07], P = 0.12; I 2: 0% | Insufficient data | Insufficient data | Insufficient data |
| Back pain | SMD 0.27 [0.00, 0.53], P = 0.05; I 2: 90% | Insufficient data | SMD 0.26 [−0.58, 1.10], P = 0.55; I 2: 95% | SMD 0.15 [−0.20, 0.51], P = 0.39; I 2: 76% |
| Leg pain | SMD 0.13 [0.06, 0.21], P < 0.001; I 2: 0% | Insufficient data | SMD 0.02 [−0.17, 0.20], P = 0.86; I 2: 0% | SMD 0.13 [−0.02, 0.28], P = 0.08; I 2: 0% |
| Complications | OR 0.60 [0.34, 1.04], P = 0.07; I 2: 35% | OR 0.49 [0.11, 2.23], P = 0.36; I 2: 68% | OR 0.77 [0.45, 1.33], P = 0.35; I 2: 0% | OR 0.42 [0.09, 1.94], P = 0.27; I 2: 37% |
| Reoperation | OR 1.17 [0.71, 1.93], P = 0.54; I 2: 52% | OR 1.39 [0.33, 5.93], P = 0.66; I 2: 80% | Insufficient data | Insufficient data |
| Duration of surgery | MD −85.18 min [−122.79, −47.57], P < 0.001; I 2: 99% | MD −104.40 min [−168.75, −40.04], P = 0.001; I 2: 96% | MD −81.21 min [−129.40, −33.03], P = 0.001; I 2: 98% | MD −115.38 min [−160.05, −70.71], P < 0.001; I 2: 91% |
| Blood loss | MD −262.65 mL [−313.45, −211.85], P < 0.001; I 2: 87% | MD −345.00 mL [−458.89, −231.11], P < 0.001; I 2: 71% | MD −267.15 mL [−326.17, −208.14], P < 0.001; I 2: 90% | MD −277.09 mL [−395.15, −159.03], P < 0.001; I 2: 89% |
| Length of hospital stay | MD −2.64 d [−3.58, −1.70], P < 0.001; I 2: 91% | MD −2.14 d [−3.12, −1.16], P < 0.001; I 2: 49% | MD −2.09 d [−2.69, −1.49], P < 0.001; I 2: 62% | MD −2.03 d [−2.62, −1.44], P < 0.001; I 2: 70% |
Data in brackets represent 95% CIs.