| Random sequence generation (selection bias) | Allocation concealment (Selection bias) | Blinding of participants and personnel (performance bias) | Blinding of outcome assessment (Detection bias) | Incomplete outcome data (attrition bias) | Selective reporting (reporting bias) | |
|---|---|---|---|---|---|---|
| Primrose 2014 |  |
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| Nordlinger 2013 | |
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| Ychou 2009 | |
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| Portier 2006 |  |
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