The Design And Experimental Research Of Ni-Ti Shape Memory Laminoplasty System

To design and manufacture a new kind of cervical spinal shape memory alloy laminoplasty system. Method Evaluate the basic character of the CSMLP with electric measurement assessment and encircle strength of holding part. Establish laminoplasty animal model, two group,ODL group (9 goats) and CSMLP group (9 goats), undergoing C4-C6 laminoplasty in ODL group and the other open-door laminoplasty with CSMLP fixation. Lateral cervical spine radiographs and cervical spine CT scan were obtained preoperatively and at 1week and 12 week post-operation. After 3 goats in each group were killed at 12 weeks post-operation, histomorphological observation were performed. After 6 goats in each group were killed at 24 weeks post-operation, biomechanical testing (range of motion in flexion-extension, lateral flexion and axial rotation) was performed using pure moment loading on 30 intact cervical spinal columns, blank group(6 goats),instant post-laminoplasty(6 goats) and instant post-laminoplasty with CSMLP fixation (6 goats). Result The maximum Stress of the CSML's holding part was 25.40±1.33Mpa, encircle strength was 119.86±7.59N. The hinged side of All specimen in CSMLP group were fused and 7of 9 in ODL group were fused also. Newly formed bone grew along CSMLP which was a frame. CSMLP could promote lamina regeneration. Instant flexion-extension range of post-operation was larger than the control group(p<0.05). Conclusions .CSMLP can open and cramp lamina automatically. It was easy to be performed and the fixation effect was stably. IThe instant cervical spine curvature and cervical spine curvature 24 weeks post-operation decreased significantly. The healing of hinged side was good by using CSMLP. Instant range of flexion- extension decreased after laminoplasty. laminoplasty increase unsteadiness at the early time post-operation. CSMLP can improve the instant stability in flexion-extension post-operation by increase the antibending section modulus. Laminoplasty did not change instant lateral flexion and axial rotation post-operation in the condition of weather use CSMLP or not. The range of motion decreased significantly medium or long period after laminoplasty in the condition of weather use CSMLP or not.