国人腰椎峡部裂直接修补螺钉的解剖学参数测量

Anatomic parameters for direct intralaminar screw repair of lumbar spondylolysis in Chinese

目的:测量国人下腰段腰椎峡部裂直接修补螺钉的手术相关解剖学参数,探讨国人应用该方法的可行性及适当的螺钉规格.方法:随机选取18至40岁成年人腰椎三维CT影像资料男女各40名作为研究对象,在其第3、4、5腰椎3个节段确定以椎板下缘中点为理想进钉点,与峡部上下表面最凹陷两点连线中点所在线段止于同侧椎弓根上切迹骨皮质最凹陷处为理想钉道,测量所在矢状面进钉长度、峡部上径、下径、外径、进钉角度及水平面正中距离、冠状面外偏角度等手术相关参数,统计性别与节段间各参数的差异.结果:各节段间左右双侧各参数无差异,平均进钉长度第3腰椎35.79 mm大于第4腰椎34.74 mm、大于第5腰椎31.52mm,平均外径第3腰椎6.98 mm小于第4腰椎7.52mm、小于第5腰椎7.91mm,平均正中距离第3腰椎9.26 mm小于第4腰椎10.64mm、小于第5腰椎12.99mm,平均外偏角第3腰椎7.23°大于第4腰椎6.41°、大于第5腰椎4.06°,差异均具有统计学意义;各节段头偏角度无差异.男性各节段进钉长度及头偏、外偏角度均大于女性.结论:峡部裂直接修补螺钉既定的理想进钉点与钉道适用于国人第3～5腰椎各节段的峡部裂解剖学特征,大部分研究对象适用4.5mm直径的螺钉.

Objective:To determine anatomic parameters for ideal intralaminar screw trajectory and the feasibility of screw placement for direct intralaminar screw repair of spondylolysis.Methods:80 randomly selected normal adult lumbar computed tomographic scans(40 for each gender) were chosen as subjects of our research.With the help of the imaging software for 3-dimensional interactive viewing,the ideal intralaminar screw trajectory was drawn from the inferior lamina through the middle point of the narrowest part at the isthmus to the upper cortical bone edge of the pedicle.We measured the ideal screw length,insert angle,outer diameter of the cortex at the isthmus in the sagittal plane,lateral angle in the coronal plane,and the distance from the insertion point to the spinous process in the transverse plane bilaterally from L3 to L5.The differences between gender and each segment were analyzed.Results:There was no statistical difference bilaterally.At the ideal trajectory,the mean screw length decreased from cranial to caudal,which was 35.79 mm at L3,34.74 mm at L4 and 31.52 mm at L5,respectively.Meanwhile,the mean outer diameter of the isthmus in the sagittal plane and the distance from the insert point to the spinous process in the transverse plane decreased at L3 6.98 mm & 9.26 mm,L4 7.52 mm & 10.64 mm,and L5 7.91 mm & 12.99 mm,respectively.However,there was no statistical difference.between each segment in the mean screw sagittal angle.The screw length and insert angle of men were greater than those of women.Conclusion:At the ideal screw trajectory designed by our research,pars fixation by direct intralaminar screw is feasible at L3 to L5 laminae,where most Chinese patients can accommodate a 4.5 mm screw.