Correction to: Trials (2018) 19: 633

https://doi.org/10.1186/s13063-018-2993-9

Following publication of the original article [1], we have been notified that the final specification of randomisation implemented in the study is slightly different to that stated in the protocol and needs to be corrected as follows:

  • Allocation will be stratified by centre and minimised on patient age (≥ 65 or < 65 years), gender, and presence of FBSS or not