Table 2

Outcomes of RCTs in this meta-analysis

Patients (n)Studies (n)RR or SMD (95% CI)P valueI2 (%)
Primary outcome
Risk of failed procedures2813280.58 (0.39 to 0.85)0.00527
Secondary outcomes
First attempt to failure68080.43 (0.30 to 0.62)<0.0000152
Mean attempts to success232622−0.61 (−0.80 to –0.43)<0.0000175
Headache and backache100370.63 (0.46 to 0.85)0.030
Mean procedure time140015−0.14 (−0.49 to 0.21)0.0490
Neurological complications85051.29 (0.54 to 3.09)0.5653
  • RCT, randomised control trial; RR, relative risks; SMD, standardised mean difference.