有限元分析颈椎棘突骨折内固定有效性

Finite Element Analysis of Internal Fixation in Cervical Spinous Process Fracture

通过对颈椎棘突骨折(累及椎板)内固定治疗有限元模型的建立和分析,明确此种治疗方式对颈椎棘突骨折的有效性。先建立正常全颈椎(C0-T1)的有限元模型并与文献报告进行对比验证,模型验证后,在正常模型基础上建立颈椎棘突骨折(累及椎板)模型,并模拟直型接骨板行内固定治疗,测量并比较颈椎棘突骨折模型及手术内固定模型和原始正常模型在前屈、后伸、左右侧弯、左右旋转6种条件下活动度改变。以及颈椎各结构的应力变化。结果表明,在正常模型上结合临床病例建立的颈椎棘突骨折(累及椎板)外观逼真,生物力学相似度良好。骨折模型部分节段,主要为C7-T1的活动度(前屈+后伸9.20°,左右侧弯5.83°,左右旋转13.12°)较正常模型(前屈+后伸7.11°,左右侧弯4.92°,左右旋转9.59°)增大,尤其是旋转活动度,模拟植入内固定后稳定性增加(前屈+后伸4.07°,左右侧弯2.21°,左右旋转2.91°),且内固定钢板应力分析提示,承受最大应力值在安全范围。颈椎棘突骨折(累及椎板)及内固定模型可以较好地模拟临床实际病例,通过有限元分析预示,此型骨折存在潜在不稳的可能性,探讨微型棘突钢板在骨折手术治疗中的应用,具有一定的临床参考价值。

The aim of this work is to establish a three-dimensional finite element model of cervical spinous process fracture （extension into the lamina） after internal fixation and assure its availability to surgical treatment. Based on a finite element model of a normal cervical spine, a finite element model of cervical spinous process fracture （extension into the lamina） was developed according to the clinical case, with which an internal fixation therapy on fracture model was simulated. The range of motion （ROM） under flexion, extension, lateral-bending and axial rotation were measured and analyzed in the normal and fracture model and fixation model. The force loading was applied on both vertebra and internal fixation to elucidate the safety of this surgical therapy. It was shown that the finite element model of cervical spinous process fracture （extension into the lamina） had a high similarity and profile to the clinical ease. The range of motion （ROM） on C7-T1 segment under each movement in fracture model （flexion ＋ extension 9.20°, lateral-bending 5.83°, axial rotation 13.12°） was larger than that in the normal model（ flexion ＋ extension 7.11 °, lateral-bending 4.92°, axial rotation 9.59°） , especially in the rotation movement. The whole cervical vertebra was more stable under internal fixation （flexion ＋ extension 4.07°, lateral-bending 2.21°, axial rotation 2.91°） with the safety of internal fixation system. In conclusion, the finite element model could be used to simulate the biomechanics of cervical spinous process fracture （extension into the lamina） to indicate the potential for delayed instability.