新型钛合金颈椎前路接骨板的三维稳定性试验

Biomechanical evaluation of anterior multifunctional cervical plate system made of a new type of titanium-alloy

背景:目前,颈椎前路接骨板已经广泛应用于颈椎创伤、畸形、退行性变以及颈椎肿瘤的治疗。目的:应用新型钛合金研制颈椎前路多功能接骨板(multifunctional cervicalplate,MCP),并且对其进行三维稳定性试验。方法:收集24具6个月左右宰杀的猪颈椎标本随机分为4组,每组6具标本。在连续的4种状态下,即完整状态、植骨状态、接骨板固定状态以及疲劳测试后状态,对颈椎C3-C7施加2.0Nm的纯力矩,测量标本前屈、后伸、左右侧屈、左右旋转的活动范围(rang of motion,ROM)和中性区(neutral zone,NZ)。结果:所有节段在6个方向的ROM上,MCP固定状态、MCP疲劳状态、C-mark接骨板(C-markplate,CMP)固定状态、CMP疲劳状态之间相比较,差异无统计学意义(P>0.05),但与完整状态、植骨状态相比较,差异均有显著统计学意义(P<0.01)。在前屈、左右侧屈方向的ROM上,植骨状态与完整状态相比较,差异有显著统计学意义(P<0.01)。在屈伸NZ上,MCP固定状态、MCP疲劳状态、CMP固定状态、CMP疲劳状态之间差异无统计学意义(P>0.05),但与完整状态、植骨状态相比较,差异均有显著统计学意义(P<0.01)。在侧屈NZ上,除完整状态与其他状态之间有统计学意义外(P<0.01),其他状态之间没有差异(P>0.05)。在旋转NZ上,所有状态之间均无统计学意义(P>0.05)。结论:体外生物力学研究表明MCP能够给颈椎提供足够的三维稳定性,在进行扭转疲劳试验后仍然可以保持三维稳定性。

Background： To date, anterior surgery for the cervical spine has been performed in spinal fractures, spinal tumors, and degenerative cervical disorders. Objective： Anterior multifunctional cervical plate （MCP） was designed and made by a new type of titanium-alloy. Flexibility test was made to analyze the characteristics of the MCP. Methods： Totally 24 porcine specimens （C3-C7） （median age 6 months） were collected and randomly divided into 4 groups with 6 specimens in each group. Each specimen was loaded in vitro with pure moments of ±2.0 Nm in flexion/extension, lateral bending, and axial rotation. Range of motion （ROM） and neutral zone （NZ） were measured in the intact state, with anterior cervical corpectomy in C4-C6 without plating, after addition of either a MCP or C-mark plate （CMP） and after 2000 cycles of axial torsion. Results： All the segments in all loading directions of ROM, no differences were found among MCP fixed state, MCP fatigue state, CMP fixed state and CMP fatigue state. But there were significant differences between the above states and the intact and grafted states （P0.01）. In flexion and lateral bending of ROM, significant difference was found between the intact and grafted states （P0.01）. In the NZ of flexion/extension, no differences were found among MCP fixed state, MCP fatigue state, CMP fixed state and CMP fatigue state. But when the above states compared with the intact and grafted state, significant differences were found （P0.01）. In the lateral NZ, significant difference was found between the intact state and other states, but no significant differences were found among other states. In the rotational NZ, no significant differences were found among all the states. Conclusions： MCP can provide three-dimensional stability of the cervical spine in the flexibility test. After the torsional fatigue test, the MCP can still provide enough stability.