Development of spinal implant Development of spinal implant rod made of Ti-29Nb-13Ta-rod made of Ti-29Nb-13Ta-

4.6Zr4.6Zr

Spinal fixationSpinal fixation

Plug

Rod

Screw

Fig. The spinal fixation method for treatment of scoliosis, a) picture of women with scoliosis ,b) X-Ray of Curve before surgery, c) Fixation during surgery, d)X-Ray after surgery

a) b) c) d)

Collaborative projectCollaborative project

Showa Ika

Kogyo Co., Ltd

Project managementPatent standerd

America(Dr.

Burger)

TohokuUniversi

tyBasic study

Europe(Prof. Steib)

Comments and needsAnimal experiment

Medical doctors

Study in Tohoku Univ.Study in Tohoku Univ.

500

600

700

800

900

Ma

xim

um

Cyc

lic S

tre

ss,σ

ma

x/M

Pa

Fig. S-N curves of Ti-29Nb-13Ta-4.6 subjected to various thermo-mechanical treatment in air.

Number of Cycles to Failure ， Nf

105 106 107104103 108

1000

1100

Improvement of fatigue propertyProcess 1Solution treatment → aging treatmentProcess 2Cold rolling → aging treatmentProcess 3Swaging → aging treatment

Ti64 rod(Conventional material of implant rod)