[1] Chonnam Natl Univ, Med Sch, Dept Neurosurg, Hwasun, South Korea
[2] Hwasun Hosp, Hwasun, South Korea
[3] Seoul Natl Univ, Childrens Hosp, Div Pediat Neurosurg, 101 Daehak Ro, Seoul 03080, South Korea
[4] Seoul Natl Univ, Childrens Hosp, Clin Pediat Neurosci Ctr, 101 Daehak Ro, Seoul 03080, South Korea
[5] Seoul Natl Univ, Coll Med, Dept Anat, Seoul, South Korea
[6] Chonnam Natl Univ, Dept Neurosurg, Med Sch & Hosp, 160 Baekseo Ro, Gwangju 61469, South Korea