青少年脊柱侧凸患者胸椎椎弓根螺钉置入的准确性和安全性评价

目的：探讨青少年脊柱侧凸患者胸椎椎弓根螺钉置入的准确性和安全性，以减少相关手术并发症。方法：32例青少年脊柱侧凸患者术前均对畸形脊柱进行标准俯卧位CT加密扫描，测量进钉点至椎体前缘的深度、进针角度、椎弓根直径和椎体的旋转角度，根据测得数据确定椎弓根螺钉置入的深度和方向，置入螺钉后再行脊柱全长X线片及CT扫描评价置钉的准确性和安全性。结果：32例共置入226枚胸椎椎弓根螺钉，术后CT加密和X线片观察到205枚螺钉（90．7％）完全在椎弓根皮质骨内。10例21枚螺钉（9.3％）发生错置，7枚螺钉（3．1％）偏外，5枚螺钉（2．2％）偏前外侧（其中2枚螺钉靠近节段血管），4枚螺钉（1．8％）偏下，4枚螺钉（1．8％）直径过大导致椎弓根内壁膨胀内移，1枚螺钉（0．4％）误入椎管导致完全性脊髓损伤。T1～T4错置12枚（18．2％），T5～T12错置9枚（6．1％）；凸侧椎根螺钉置入的准确率为93．8％，凹侧为83．1％。结论：脊柱畸形患者术前应常规采用标准俯卧位CT加密扫描，根据扫描图像测得的相关数据可为术中准确置入椎弓根螺钉提供重要参考依据。在青少年脊柱侧凸患者胸椎椎弓根螺钉置入有一定的误置率，螺钉发生错置多见于上胸椎和凹侧．术中应高度重视。

The assessment of accuracy and safety of thoracic pedicle screw placement in adolescent scoliosis

Objective:To investigate accuracy and safety of pedicle screw placement in thoracic spine of adolescent scoliosis in order to reduce the related complications of the operation.Method:On the basis of imaging of thoracic vertebral pedicles in 32 cases of adolescent scoliosis,the screw prick point,angle,depth,diameter of vertebral pedicle and rotative angle of vertebra(VRA) were measured and defined on the thoracic vertebrae pedicle by CT thin-slice scan in standard prone in all cases.The accuracy and safety of screws placement were evaluated with whole length spine X-ray and CT thin-slice scan in all cases postoperatively.Result:Of the total 226 thoracic pedicle screws inserted in 32 cases,205 screws(90.7%) were fully contained within the cortical boundaries of the pedicle,21 screws(9.3%) were misplaced in 10 cases.7 screws(3.1%) laterally,5 screws(2.2%) anterolaterally(2 screws close to aortic abutment),4 screws(1.8%) caudad perforations,4 screws(1.8%) medial wall migrated to the canal,one screw(0.4%) was misplaced in vertebral canal (lead to complete spinal cord injury).Conclusion:The thoracic vertebral pedicle of spinal deformity should be measured by thin-slice CT scan in standard prone in all cases preoperatively.Thoracic pedicle screw placement in adolescent scoliosis is of a certain ration of misplacement,screws are more easily misplaced on the concave side proximally,and care should be taken during the operation.