[1] Hamamatsu Univ Sch Med, Dept Orthopaed Surg, Higashi Ku, Handayama 1-20-1, Hamamatsu, Shizuoka 4313192, Japan
[2] Niigata Spine Surg Ctr, Konan Ku, Nishimachi 2-5-22, Niigata 9500165, Japan
[3] Yokohama Brain & Spine Ctr, Dept Spinal Surg, Isogo Ku, Takigashira 1-2-1, Yokohama, Kanagawa 2350012, Japan
[4] Seirei Sakura Citizen Hosp, Dept Orthopaed Surg, Ebaradai 2-36-2, Sakura, Chiba 2858765, Japan
[5] Dokkyo Med Univ Koshigaya Hosp, Dept Orthopaed Surg, Minamikoshigaya 2-1-50, Koshigaya 3438555, Japan
[6] Hirosaki Mem Hosp, Dept Orthopaed Surg, Sakaizekinishita 59-1, Hirosaki, Aomori 0368076, Japan
[7] Natl Hosp Org Kobe Med Ctr, Dept Orthopaed Surg, Suma Ku, Nishiochiai 3-1-1, Kobe, Hyogo 6540155, Japan
[8] Konan Kosei Hosp, Dept Orthopaed Surg, Takayacho Omatsubara 137, Konan 4838704, Japan
[9] Meijo Hosp, Dept Orthopaed Surg, Naka Ku, Sannomaru 1-3-1, Nagoya, Aichi 4600001, Japan
[10] Kitasato Univ, Sch Med, Dept Orthopaed Surg, Minami Ku, Kitasato 1-15-1, Sagamihara, Kanagawa 2520375, Japan
[11] Shinshu Univ, Dept Orthopaed Surg, Asahi 3-1-1, Matsumoto, Nagano 3908621, Japan
[12] Okayama Univ Hosp, Dept Orthopaed Surg, Shikatacho 2-5-1, Okayama 7008558, Japan
[13] Dokkyo Med Univ, Dept Orthopaed Surg, Kitakobayashi 880, Mibu, Tochigi 3210207, Japan
[14] Gifu Prefectural Gen Med Ctr, Dept Orthopaed Surg, Noisshiki 4-6-1, Gifu 5008717, Japan
[15] Tokai Univ, Sch Med, Dept Orthopaed Surg, Shimokasuya 143, Isehara, Kanagawa 2591193, Japan
[16] Gunma Spine Ctr, Dept Orthopaed Surg, Kamitoyookamachi 828-1, Takasaki, Gunma 3700871, Japan
[17] Juntendo Univ, Sch Med, Dept Orthopaed Surg, Bunkyou Ku, Hongo 3-1-3, Tokyo 1138431, Japan
[18] Keio Univ, Dept Orthopaed Surg, Shinjuku Ku, Shinanomachi 35, Tokyo 1608582, Japan