体位改变对腰椎前斜入路通道影响的影像学分析

A radiographic evaluation on the effect of body position change on retroperitoneal oblique corridor

中文关键词:  磁共振成像  前斜入路  体位改变  解剖学特点

英文关键词:MRI  Oblique lateral approach  Position change  Anatomical characteristic

中文摘要:

  【摘要】 目的：探讨体位变化对L1～L5腰椎前斜入路椎间融合术（oblique lateral interbody fusion，OLIF）通道大小的影响。方法：随机选取40例健康志愿者，分别在仰卧位及右侧卧位进行L1～L5 MRI扫描。在位于椎间盘中点的图像内定义椎间盘中心点为O；A（平卧位）/A′（右侧卧位）点以及B（平卧位）/B′（右侧卧位）点为∠AOB（∠A′OB′）达到最小值时主动脉（或髂血管）左侧壁以及腰大肌前内侧壁上的点，记录各节段AB及A′B′的距离，并在各节段将AB与A′B′比较；将L1～L5各节段的A′B′进行节段间比较，并探讨其与性别、体重指数（body mass index，BMI）及腰大肌截面积（relative psoas cross-sectional area，PCSA）之间的关系。结果：40例志愿者的BMI值为18.4~26.5，6例存在主动脉高分叉现象；各节段AB和A′B′（mm）：L1/2为14.80±3.89和12.37±3.62，L2/3为12.85±4.16和9.96±3.37，L3/4为12.24±4.10和10.85±3.30，L4/5为9.78±4.69和9.72±4.37；主动脉高分叉者L4/5为7.72±3.56和6.71±2.86。在L1/2、L2/3、L3/4节段A′B′值显著小于AB（P=0.005，0.003，0.020）；L4/5节段无论是否存在主动脉高分叉现象均无统计学差异（P=0.946，0.097）；不同节段间A′B′值存在显著差异（P=0.046），通道大小趋势为L1/2＞L3/4＞L2/3＞L4/5＞主动脉高分叉者L4/5（其中L1/2显著＞主动脉高分叉者L4/5，P=0.003）；男女性间A′B′在各节段无统计学差异（P均＞0.05）；BMI与PCSA在L3/4与A′B′呈负线性相关（P=0.015，0.000），而PCSA在L1/2也与A′B′呈负线性相关（P=0.024）。结论：右侧卧位时，OLIF通道解剖空间在L1/2、L2/3、L3/4水平显著减少，平卧位MRI对通道空间评估价值有限；而且OLIF通道大小与腰椎节段水平有关，并且受BMI值和腰大肌横截面积影响。

英文摘要:

  【Abstract】 Objectives: To analyze whether right lateral decubitus position would change the retroperitoneal oblique corridor to the L1-L5 intervertebral discs. Methods: 40 volunteers were randomly enrolled and MRI(magnetic resonance imaging) scan was performed from L1 to L5 in supine and right lateral decubitus positions respectively. In image across the center of each disc, O was defined as the center of a disc; A(supine)/A′(right lateral decubitus) and B(supine)/B′(right lateral decubitus) were located in left lateral border of the aorta(or iliac artery) and the anterior medial border of the psoas. The distances of AB and A′B′ of all levels were measured and were compared with each other at all levels; A′B′ of different levels was compared and the associations with sex, BMI(body mass index) and relative psoas cross-sectional area(PCSA) were explored. Results: BMI of 40 subjects ranged from 18.4 to 26.5 and 6 cases had high aortic bifurcations. The distances of AB and A′B′(mm) at each level were: L1/2, 14.80±3.89 and 12.37±3.62; L2/3, 12.85±4.16 and 9.96±3.37; L3/4, 12.24±4.10 and 10.85±3.30; L4/5, 9.78±4.69 and 9.72±4.37, L4/5 of subjects with high aortic bifurcation, 7.72±3.56 and 6.71±2.86. AB was significantly larger than A′B′ at L1/2, L2/3, L3/4(P=0.005, 0.003, 0.020) without significant difference at L4/5 no matter whether the subjects had high aortic bifurcation or not(P=0.946, 0.097). There was significant difference between levels(P=0.046), A′B′ in L1/2 was largest, followed by L3/4, L2/3 and L4/5. There was no difference of A′B′ at each level between sexes(all P＞0.05). Negative linear relationship were found among A′B′, BMI and PCSA at L3/4(P=0.015, 0.000) and A′B′ at L1/2 was also affected by PCSA(P=0.024). Conclusions: Retroperitoneal oblique corridors at L1/2, L2/3 and L3/4 decreased from supine to lateral position, which meant that the value of pre-operative lumbar MRI images obtained at supine position might be limited and more intra-operative psoas tractation should be needed. Oblique corridors were different between levels and BMI, PCSA could affect the corridors at L1/2 and L3/4, which should also be taken into consideration before operation.