1. Neurosurgical Trials Group, Newcastle University, Newcastle upon Tyne, United Kingdom.
2. Newcastle Clinical Trials Unit, Newcastle University, Newcastle upon Tyne, United Kingdom.
3. Health Economics Research Unit, University of Aberdeen, Aberdeen, United Kingdom.
4. Department of Medical Physics, South Tees Hospitals Foundation Trust, James Cook University Hospital, Middlesbrough, United Kingdom.
5. Department of Neurosurgery, Heidelberg University, Heidelberg, Germany.
6. Royal Victoria Infirmary, Newcastle upon Tyne, United Kingdom.