[1] Univ Hong Kong, Med Ctr, Queen Mary Hosp, Div Surg,Dept Paediat Surg, Hong Kong, Hong Kong, Peoples R China
[2] St Bartholomews & Royal London Sch Med & Dent, Acad Dept Surg, London, England
[3] St Bartholomews & Royal London Sch Med & Dent, Acad Dept Neurol, London, England
[4] Washington Univ, Sch Med, St Louis, MO USA