[1] Yonsei Univ, Gangnam Severance Hosp, Dept Neurosurg, Coll Med, Seoul, South Korea
[2] Yonsei Univ, Gangnam Severance Hosp, Dept Radiol, Coll Med, Seoul, South Korea
[3] Catholic Univ Korea, Dept Neurosurg, Incheon St Marys Hosp, Incheon, South Korea
[4] Seoul Ewha Womans Univ, Dept Neurosurg, Med Ctr, Seoul, South Korea
[5] Catholic Univ Med, Dept Neurosurg, Seoul St Marys Hosp, Seoul, South Korea