[1] Soonchunhyang Univ, Bucheon Hosp, Dept Neurosurg, Bucheon 14584, Gyeonggi Do, South Korea
[2] Catholic Univ Korea, St Vincents Hosp, Dept Neurosurg, Suwon 16247, Gyeonggi Do, South Korea
[3] Hallym Univ, Hangang Sacred Heart Hosp, Dept Neurosurg, Seoul 07247, Gyeonggi Do, South Korea
[4] Soonchunhyang Univ, Bucheon Hosp, Dept Neurosurg, 170 Jomaru Ro, Bucheon 14584, Gyeonggi Do, South Korea