兔腰神经根的解剖位置及实验性硅胶管压迫程度的测量

Anatomic localization of lumbar spinal nerve root and the determination of compression in rats

目的 确定兔腰神经根的解剖位置及硅胶管在椎间管内压迫神经根的程度。方法 18只纯种新西兰成年兔 ,雄性 ,随机分为 2组 :A组 6只 ,利用几何作图原理 ,测量脊神经的长度、角度、脊神经在椎间外孔的直径及椎间外孔面积等解剖特点 ;B组 12只 ,采用断层解剖技术 ,6只用于测量冠状面和椎间外孔矢状面上硅胶管的压迫程度 ,6只用于关节突关节矢状面的压迫程度。测量工具主要有 :圆规、量角器和游标卡尺。结果 脊神经长度、与硬脊膜的夹角及椎间外孔面积在不同椎间隙各不相同。L5、L6脊神经长度分别为5 .83± 1.18和 8.94± 1.64mm ,与硬脊膜的夹角分别为 5 5 .2± 11.1和 2 9.6± 4.2°。硅胶管的截面积为椎间管经关节突关节矢状面面积的 2 0 %左右 ,为椎间外孔面积的 5 0 %左右。结论 本模型为脊神经轻度受压实验模型 ,接近于临床椎间盘突出和椎间管狭窄对脊神经的压迫。按照A组实验的结果进行插管 ,实验成功率高 。

Objective To investigate the anatomic lumbar nerve root localization and to measure the degree of compression induced by silastic tube implantation in rats. Methods Eighteen pure New Zealand rabbits, weighing from 2.5 kg to 3.0 kg, were randomly allocated into 2 groups:group A ( n =6), in which the animals were dissected according to the geometrical principles to localize the lumbar spinal nerve roots, and the length of spinal nerve, the angle to the dura matter, and the anatomical characteristics such as the diameter of the spinal nerve at the external intervertebral foramen and the sagittal area of the foramen were measured; group B ( n =12), from which the extent of compression of intervertebral foramen was measured by using the sectional anatomic techniques after the artificial implantation of a silastic tube was performed. Results The length of lumbar intervertebral canal, the angle and area of intervertebral foramen varied at various lumbar intervertebral spaces; the length of the spinal nerve root was 5.83 ±1.18mm at L 5～6 and 8.94±1.64mm at L 6～7 , its angles to the dura matter were 55.2±11.1° and 29.6± 4.2° , respectively, on condition that the measured sectional area of the silastic tube was 20% of the sagittal area of the intervertebral canal and 50% of the area of the external intervertebral foramen. Conclusion The animal models of spinal nerve root compression established in this experimental study is similar to that seen in clinical settings. It is suggested that high successful intubation rate and slim possibility of injury to the spinal cord can be expected if it is manipulated in the way described above.