PEEK (by Invibio) cages for posterior lumbar intersomatic fusion (PLIF). Twin Peaks design comes close to disc space anatomy: - Improve primary stability - Prevent secondary pull-out - Favor bone ingrowth/secure arthrodesis - Correct intervertebral height - Restore physiological lordosis - 2 lengths : 20 mm and 25 mm - 3 angles : 0°, 4°, 8° - 7 heights : from 8 mm to 14 mm PEEK (by Invibio) material is recognized for its properties : - very close to bone elasticity - Radiolucency permits to observe the growth of bone graft - Very compact instrumentation : only 1 container