Screw path of pedicle of upper thoracic spine and anatomical positions of prevertebral key structures: computed tomography evaluation

doi:10.3969/j.issn.2095-4344.2014.26.017

Abstract

Abstract:

BACKGROUND: The structure surrounding upper thoracic spine is complicated. Transverse diameter of pedicle was relatively small. There were important organs in front of the vertebral body. Screws deviated from axis or screws were too long. The safety and effectiveness of screw implantation were not implemented. It is necessary to understand the key structure of surroundings.
OBJECTIVE: To analyze the relationship of anatomic position between the axis of screw of pedicle of upper thoracic spine and key adjacent structure of the vertebral body.
METHODS: A total of 30 healthy adult volunteers received T₁-T₄ pedicle axis parallel to CT scans. The positions of esophagus, trachea position, aortic arch, carotid and vertebral arteries were observed when the pedicle screw was implanted along the pedicle axis. The shortest distance on both sides of a vertebral pedicle axis from these structures was measured. Paired t-test was utilized for analysis.
RESULTS AND CONCLUSION: 240 measurement parameters were analyzed. The distance from the left pedicle axis on T _1-3 to esophagus was small, and the left pedicle on T₂was minimal. The distance from the right pedicle axis on T_2-4 to trachea was small. The distance from right pedicle axis on T₃, T₄to right main bronchus was small. Carotid and vertebral artery did not show the risk of injury. 62% of the patients were in the aortic arch on T₄ plane, and no risk of damage was found. These results indicated that the left pedicle screws were easy to damage the esophagus, and the right pedicle screw was easy to damage trachea. Carotid artery, vertebral artery and aortic arch were not easy to be damaged. The anatomic position of easily damaged structure could be identified by careful analysis of CT data before screw implantation in the pedicle of upper thoracic spine.

中国组织工程研究杂志出版内容重点：人工关节；骨植入物；脊柱；骨折；内固定；数字化骨科；组织工程

全文链接：

Key words: internal fixators, thoracic vertebrae, anatomy, esophagus, trachea

CLC Number:

R318

Xing Wen-hua, Hao Li-xia, Huo Hong-jun, Yang Xue-jun. Screw path of pedicle of upper thoracic spine and anatomical positions of prevertebral key structures: computed tomography evaluation[J]. Chinese Journal of Tissue Engineering Research, 2014, 18(26): 4190-4194.

Figures/Tables 1

2.1 参与者数量分析按意向性分析，30例成人健康志愿者T1-4椎弓根轴线CT扫描数据均进入结果分析，无脱落。 2.2 食管到轴线的距离 T1-T4椎体皮质前结构测量结果见表1。所有结构中，轴线与食管距离最近，最容易受到损伤(图1)。在T1食管位于椎体前缘中线，然后开始向左侧偏离下降。轴线至食管的平均距离为左侧3.0 mm，右侧5.8 mm。T2左侧最小2.3 mm，左侧椎弓根螺钉具有较高损伤食管的风险。 2.3 气管到焦点的距离 72%的志愿者食管位置解剖学上从T1椎体前缘中线开始下降，直到T4个椎体的右侧 (表1)。在T1水平，气管位于食管的前面，在T2-4水平气管紧邻食管。从焦点到气管的平均最短距离右侧为8.3 mm，左侧为11.6 mm。T2-4右侧椎弓根螺钉(6.5 mm)具有高危损伤率，特别是T3右侧位置具有极大的气管损伤率(P < 0.05)，T4右侧螺钉有极大损伤右侧主支气管率(P < 0.05)。 2.4 颈动脉到焦点的距离颈动脉位于焦点的前方或侧方。在所有位置中，焦点到颈动脉的距离均大于10.0 mm (表1)。焦点到颈动脉的平均距离为右侧14.5 mm，左侧为12.8 mm，左右差异无显著性意义(P < 0.05)。考虑到焦点与颈动脉的最短距离较大，暂认为颈动脉无椎弓根螺钉损伤的可能性。 2.5 椎动脉到焦点的距离椎动脉在T3-T4不出现，在T1-T2椎动脉位于螺钉的侧方或前方(表1)。焦点到椎动脉平均距离右侧为12.5 mm，左侧为18.3 mm。因此，也认为椎弓根螺钉不会有椎动脉损伤的可能性。 2.6 主动脉弓到焦点的距离 62%的患者T4水平有主动脉弓的出现。1例患者出现在T2水平。主动脉弓出现在T4水平的患者，20%位于椎体中线，80%位于椎体左侧。T4焦点到主动脉弓的平均距离为8.1 mm。尽管沿左侧椎弓根主动脉弓有下降趋势，但无椎弓根螺钉损伤的风险性。 "

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