The invention concerns a dynamic stabilizer system for dynamically stabilizing the sacrum and at least lumbar vertebra L5. The system comprises: ⋅ two anchoring members (12, 14) in the sacrum, said members being implanted at distinct locations； ⋅ two distinct rigid rods (16, 18), each presenting a first end and a second end, each second end being secured to an anchoring member (12, 14) in such a manner that the point at which each rod is secured close to its second end can be adjusted； and ⋅ a mechanical fastener element (20) fastened on the process of a lumbar vertebra (A), said mechanical fastener element presenting a first end and a second end (26, 28), the first end (16a, 18a) of each rigid rod being secured to a respective one of the ends of said mechanical fastener element, said mechanical fastener element including a flexible portion (22, 24).
