胸椎椎弓根外内固定技术的临床应用

目的:研究胸椎椎弓根外内固定技术的安全性和有效性。方法:应用胸椎椎弓根外内固定技术在2004年至2010年治疗13例患者,术前采用CT加密扫描测量进钉点、进钉点至椎体前缘的深度、进钉角度和直径,根据测量结果术中椎弓根钉入钉点为横突尖,进钉方向为平均向头侧倾斜10°～20°、内倾角26°～40°,顺椎弓根外侧皮质进入椎体。结果:术后CT加密扫描观察螺钉周围的皮质骨是否完整,是否靠近节段血管,是否穿透皮质骨。评价置入钉的准确性和安全性。13例患者共置入64枚椎弓根螺钉,术后CT加密扫描和X线片观察到60枚(93.7%)螺钉置入准确,4枚(6.3%)螺钉发生错置。结论:实验结果表明,胸椎椎弓根外内固定与胸椎椎弓根内固定相比,具有更宽的置入宽度、更长的螺钉长度及更大的螺钉直径,具有安全可靠、简单实用的优点,并具有生物力学优越性,是胸椎后路内固定的一种良好选择。

Clinical application of extrapedicular screw fixation in thoracic spine

Objective:To evaluate the efficacy and safety of extrapedicular screw fixation in thoracic spine.Methods:13 cases were treated with extrapedicular screw fixation between 2004 and 2010.Prior to the operations,the screw entrypoints,angles,depths and diameters,on the thoracic vertebrae pedical,were determined by the measurements from standard CT thin-slice scan.The screw entrypoints were located at the tip of transverse process.The average inclination angle is between 10° and 20° towards head and between 26°and 40° towards neutral line respectively.The screws were inserted into the vertebral body along the external cortex of pedical.Results:The integrity of cortical bone surrounding the screws,the distance to segmental blood vessels and the penetration of cortex were observed after operation to evaluate the accuracy and safety of screw placement.Among 64 thoracic pedical screws that were implanted in the 13 cases,60 screws(93.7%)were accurately inserted inside the costotransverse unit,and 4 cases(6.3%)were misplaced according to the image of X-ray and CT thin-slice scan.Conclusion:Compared to the transpedicular fixation,extrapedicular fixation allows for wider insertion area,as well as longer and bigger screws,hence making it is a safer and simpler alternative to thoracic posterior fixation because of its theoretical biomechanical superiority.