兔腰椎间盘退变模型的建立及影像学分析

目的：建立腰椎间盘退变的动物模型并进行CR和MRI观察.方法：选用新西兰兔20只,沿右腹直肌外缘做15 cm长切口,钝性剥离腹膜至腰椎横突前外侧,咬除右侧L5、L6横突,显露上述节段椎间盘,斜形切开纤维环约1.5 mm,未伤及髓核,然后逐层缝合.所有动物在标准条件下饲养,分别于术后2、4、8、20、40周行腰椎计算机x线摄影术（CR）和核磁共振成像（MRI）以检测终板下骨及髓核的变化.结果：术后作为自体对照组的L1、2、L2、3椎间盘未见异常,而手术组L4、5、L5、6椎间盘则相继出现T2加权像低信号、腰椎不稳畸形,终板下骨质硬化,椎体边缘骨赘增生,椎间隙变窄,椎间盘后突和硬膜囊受压等改变.对手术节段及其邻近和完全正常节段椎间盘髓核信号值的定量分析显示,手术组椎间盘T2加权像信号值减低在术后4、8、20、40周与正常对照组对比具有统计学意义,而临近椎间盘L3、4、L6、7手术8周后与正常椎间盘对比有显著差异.CR扫描结果显示：手术节段椎间盘终板下信号值减低与对照组相比4周后就开始有显著差异.结论：应用纤维环切开法可获得可靠的新西兰大白兔椎间盘退变模型,可通过MRI及CR在早期加以证实.

Animal model development and imaging analyse of the degenerative disc in rabbit

Objective: To develop the animal model of degenerative disc in rabbit and to observe the change with MRI and CR. Methods: Twenty adult rabbits were subjected to annulotomy. A 15 cm' cut was made along the outer margin of right rectus abdominis, then abdominal membrane was stripped until the transverse process of L5 and L6 can be seen. After biting the transverse process of L5 and L6, annular fibrosus of L4~5 and L5~6 was cut about 1.5 mm, and then sewn up. All of the rabbits were bred in standard circumstance. The operated and controlled discs were scaned with magnetic resonance imaging(MRI) and computed radiography(CR) at 2,4,8,20,40 weeks after operation. Resuls: No difference were found in the controlled L1~2 and L2~3 disc. The lumbar unsteadness, T2WI low signal, osteophytosis, under end plate stiffness and compressed dura were found in experimental group. T2WI signal values decreased significantly at 4, 8, 20 and 40 week postoperatively. T1 signal values were not applied for their blurred image. Contrasting with that of the control group,under end plate bone CR signal value of the experimental group increased significantly at initial time and then increased gradually. Conclusions: The animal model of lumbar disc degeneration could be obtained by anteriolateral annulotomy. The disc degeneration can be found early time from MRI and CR. The decline of T2WI signal value of the nucleus pulposus is a previous and common sign of the disc degeneration, and the increase of CR signal value is an early sign for vertebrae hyperostosis.