1) Sugita Y, Tanikaze S, Yoshino K, et al : Severe hypospadias repair with meatal based paracoronal skin flap : the modified Koyanagi repair. J Urol 166 : 1051─1053, 2001
2) Hayashi Y, Mizuno K, Kojima Y, et al : Characterization of the urethral plate and the underlying tissue defined by expression of collagen subtypes and microarchitecture in hypospadias. Int J Urol 18 : 317─322, 2011
3) Hayashi Y, Kojima Y, Mizuno K, et al : The modified Koyanagi repair for severe proximal hypospadias. BJU Int 87 : 235─238, 2001
4) Hayashi Y, Kojima Y, Mizuno K, et al : Neo-modified Koyanagi technique for the single-stage repair of proximal hypospadias. J Pediatr Urol 3 : 239─242, 2007
5) Catti M, Lottman H, Babloyan S, et al : Original Koyanagi urethroplasty versus modified Hayashi technique : outcome in 57 patients. J Pediatr Urol 5 : 300─306, 2009