[1] Orebro Univ Hosp, Dept Surg, Div Trauma & Emergency Surg, S-70185 Orebro, Sweden
[2] Orebro Univ, Sch Med Sci, S-70281 Orebro, Sweden
[3] Univ Penn, Penn Presbyterian Med Ctr, Div Traumatol Surg Crit Care & Emergency Surg, Philadelphia, PA 19104 USA
[4] Orebro Univ Hosp, Div Neurosurg, Dept Neurosurg, Orebro, Sweden
[5] Orebro Univ, Sch Med Sci, Clin Epidemiol & Biostat, S-70182 Orebro, Sweden
[6] Karolinska Univ Hosp, Dept Surg, S-17176 Stockholm, Sweden
[7] Heinrich Heine Univ, Med Sch, Dusseldorf, Germany