1. Division of Head and Neck-Plastic and Reconstructive Surgery, Department of Surgery, the Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, N.T., Hong Kong
2. Oral Maxillofacial Surgery and Dental Unit, the Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, N.T., Hong Kong
3. Department of Maxillofacial Surgery, Kings College Hospital, London.
4. Department of Anaesthesia and Intensive Care, the Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, N.T., Hong Kong