trabecula

Most bone graft granules used in lumbar posterior pedicle screw fixation with Cage supporting bone graft fusion are cancellous bones which collapse easily when bearing strong strength.11 During bone graft prophase inflammatory reaction as well as anaphase callus reconstruction and remodeling, osteoblasts can absorb necrotic bone and bone tissue outside the stress axis while forming and connecting callus.12 After implantation of large bone granules, considerable gaps are produced during bone granule accumulation and mutual extrusion, causing bone trabecula breakage.

Regardless, small-sized bone graft granules invisibly prolong the time for fiber joint formation between bone granules and end-plate due to severe bone lamella structural damage, rendering repair and reconstruction rather slow.14-16 By inducing slight bone-bone interface motion, lumbar motion after surgery is bad for bone trabecula rebuilding and repair.17 Then slow repair aggravates the bone-bone interface motion, forming a vicious circle.18,19

Compared with small-sized bone graft granules, bulk graft bone granules have advantages in forming fiber joint and callus joint due to abundant bone trabecula structure with continuity and completeness.