Objective: To investigate the impact of fixation in part lumbar segment on rat model with radiography.
Methods: One hundred and twenty SPF male SD rats (350～450g) were randomly divided into simple fixation group (SF group), rotary fixation group (RF group) and sham-operation group (Sham group). The external link fixation system was implanted into the L4-L6 of SF group and RF group rats. In RF group, L5 spinous process of rats was rotated to the right side, making the L4, L6 and L5 spinous process not in a straight line. In SF group, the external link fixation system was implanted simply and not rotated. The anterior and posterior diameter in the intervertebral space and the distance between spinous processes were examined 1, 4, 8 and 12 weeks after fixation.
Results: The anterior diameter in the intervertebral space between L3-L4, L4-L5, L5-L6, and L6-S1 of SF groups 4 weeks after fixation were 28.11 ± 3.94, 25.73 ± 4.70, 29.51 ± 6.34 and 34.97 ± 4.65 pixels; the posterior diameter were 7.39 ± 1.63, 6.65 ± 1.76, 7.02±1.52 and 9.62 ± 2.50 pixels; the distance between spinous process were 39.33 ± 11.74, 14.11 ± 5.75, 21.32 ± 6.84 and 77.43 ± 13.69 pixels, the values were less than those in Sham groups (P<0.05). The anterior and posterior diameter in the intervertebral space and the distance between spinous process of SF groups 8 and 12 weeks after fixation continuously decreased compared with Sham group rats (P<0.05). The results of RF groups were consistent with the measurement of SF groups, the anterior and posterior diameter in the intervertebral space and the distance between spinous process of RF group rats were less than those in Sham groups 4, 8 and 12 weeks after fixation (P<0.05). Osteophyte formation was observed in SF and RF groups 8 weeks after fixation.
Conclusion: The fixation in part lumbar segment can result in the decrease of intervertebral space and the formation of osteophytes.
目的: 利用腰椎X线摄片技术观察大鼠腰椎部分节段固定对椎间隙前、后径和棘突间距的影响。
方法: 120只体质量为350~450g的SPF级雄性SD大鼠随机分为单纯固定组、旋转固定组和假手术组。单纯固定组大鼠腰椎L 4-L 6节段植入椎体外部连接固定装置；旋转固定组大鼠则在此基础上于连接钢板和棘突钢板之间放置金属垫片，使L 5棘突向右侧旋转，造成L 5棘突与L 4和L 6棘突不共线；假手术组则只切开皮肤后缝合。造模1周、4周、8周和12周时大鼠腰椎X线摄片，测量各组固定节段椎间隙前、后径和棘突间距的距离。
结果: 造模4周后，单纯固定组固定节段L 3-L 4、L 4-L 5、L 5-L 6和L 6-S 1椎间隙前径分别为28.11±3.94、25.73±4.70、29.51±6.34和34.97±4.65像素；椎间隙后径分别为7.39±1.63、6.65±1.76、7.02±1.52和9.62±2.50像素；棘突间距分别为39.33±11.74、14.11±5.75、21.32±6.84和77.43±13.69像素，均小于假手术组( P < 0.05)。造模8周及12周后，单纯固定组固定节段L 3-L 4、L 4-L 5、L 5-L 6和L 6-S 1椎间隙前、后径和棘突间距与假手术组相比继续减小( P < 0.05)。旋转固定组与单纯固定组的测量结果一致，在造模4周、8周和12周后，其固定节段L 3-L 4、L 4-L 5、L 5-L 6和L 6-S 1椎间隙前、后径和棘突间距也均小于假手术组( P < 0.05)。造模8周后，单纯固定组和旋转固定组腰椎固定节段出现了较明显的骨赘。
结论: 腰椎部分节段固定可造成椎间隙减小并导致骨赘形成。