1 Division of Surgery and Interventional Science, University College London, United Kingdom; Department of Plastic Surgery, Department of Plastic and Reconstructive Surgery, Royal Free NHS Foundation Trust, Royal Free Hospital, Pond Street, London NW3 2QG, United Kingdom.
2 Department of Plastic Surgery, Department of Plastic and Reconstructive Surgery, Royal Free NHS Foundation Trust, Royal Free Hospital, Pond Street, London NW3 2QG, United Kingdom.
3 Department of Neurosurgery, National Hospital for Neurology and Neurosurgery, Queen Square, London, United Kingdom.