下颈椎椎弓根通道穿透力及突破力的生物力学研究

Biomechanical screw resistance and penetrating strength of the lower cervical pedicle screw channel

目的测定下颈椎椎弓根通道穿透力及四壁突破力,为临床安全置钉提供生物力学上依据。方法新鲜6具成人颈椎标本,制成骨性颈椎标本。以Abumi法确定各标本椎弓根进钉点,分别测定下颈椎椎弓根通道穿透力及与椎弓根轴成30°时四壁突破力。结果下颈椎椎弓根穿透力为(-187.35±42.28)N,上壁突破力为(-283.93±75.0)N,下壁突破力为(-283.33±70.41)N,内侧壁突破力为(-319.59±65.73)N,外侧壁突破力为(-264.01±63.16)N。下颈椎椎弓根穿透力与四壁突破力差异均有统计学意义(均P<0.01),内侧壁突破力均大于其他三侧壁突破力(均P<0.01)。结论根据解剖学特点及生物力学测定表明,下颈椎椎弓根置钉时,应靠近椎弓根内壁和下壁进行。

Objective To elucidate the biomechanical screw resistance and penetrating strength of the lower cervical pedicle screw channel （PSC） walls, and to provide biomechanical basis for clinical safety ofpedicte screw placement, Methods Six fresh bony cervical specimens were made. The Abumi method was used to determine the screw entry points on the vertebrae. The screw resistance through the PSC and the penetrating strength of the four walls of the PSC were measured respectively when the screw entry angle was 30 °. Results For all the vertebral specimens, the average screw resistance was prominently weaker than the penetrating strength （P 〈 0.01）. And the top limit of the penetrating strength of the PSC medial walls was significantly higher than that of the lateral, the superior and the inferior walls （19 〈 0.01）. Conclusions The anatomic basis and the biomechanical test results suggest that the lower cervical pedicle screw should be placed close to the medial and the inferior walls.