[1] Univ Barcelona, Human Anat & Embryol Unit, Fac Med & Ciencies Salut, Barcelona, Catalunya, Spain
[2] Hosp Santa Creu I Santa Pau, Anesthesia, Barcelona, Spain
[3] Royal Wolverhampton Hosp NHS Trust, Anesthesia, Wolverhampton, England
[4] Hosp Costa Sol, Anesthesia, Marbella, Spain
[5] Univ Barcelona, Lab Surg Nauroanat LSNA, Fac Med & Ciencies Salut, Barcelona, Catalunya, Spain
[6] Univ Barcelona, Fac Med & Ciencies Salut, Human Anat & Embryol, Barcelona, Catalunya, Spain
[7] Hosp Clin Barcelona, Anesthesiol, Barcelona, Spain