枕骨大孔和枕髁数字化形态的三维重建

Digital morphology of foramen magnum and occipital condyle:an observation based on three-dimensional reconstruction

背景:脑干腹侧面周围结构的病变位于颅颈交界处深面,周围毗邻重要结构,远外侧入路是基本术式,但入路时要考虑性别、侧别间的差异。目的:通过三维重建测量手段对枕骨大孔和枕髁进行形态特征分析,为临床颅底远外侧手术入路提供解剖学参数。方法:选择拍摄头颈部电子计算机断层扫描图像的成年人共673例,男448例,女225例,年龄20-87岁。经软件三维重建颅底,测量枕骨大孔长度和宽度,利用公式计算枕骨大孔面积和指数,测量枕髁长度、宽度,枕髁长轴与矢状轴的夹角,枕骨大孔前、后缘中点连线与枕髁后缘和枕骨大孔交点连线的夹角,枕骨大孔前、后缘连线中点与舌下神经管后壁中点连线的夹角。对各指标进行性别和侧别差异分析。结果与结论:(1)枕骨大孔指标中除枕骨大孔指数不存在性别间统计学差异外,其余指标均存在性别间的差异(P<0.05);枕髁指标中,除男性左枕髁宽小于女性外(P>0.05),左枕髁长、右枕髁长、右枕髁宽男性均大于女性(P<0.05);(2)男性枕髁长轴与矢状轴的夹角小于女性,且左枕髁长轴与矢状轴的夹角在性别间差异有显著性意义(P<0.05);(3)枕骨大孔前、后缘连线中点与枕骨大孔前缘中点和舌下神经管内口后壁中点连线的夹角在侧别间无统计学差异;枕髁长、枕髁宽、枕髁长轴与矢状轴的夹角、枕骨大孔前、后缘中点连线与枕髁和枕骨大孔交点连线的夹角在侧别间差异均有显著性意义(P<0.05);(4)提示枕骨大孔和枕髁的相关参数在性别和侧别间存有差异,临床远外侧髁后及经髁入路中,右侧入路暴露范围较大;男性枕骨大孔长、宽、面积均大于女性,男性枕髁长、枕骨大孔前缘中点和枕髁后缘连线与矢状面夹角大于女性,远外侧入路时应考虑性别间差异。

BACKGROUND:Lesions of structures around the ventral side of the brainstem are located in the deep surface of the craniocervical junction,surrounded by important structures.The far lateral approach is the basic surgical method,but sex and lateral differences should be considered in the approach.OBJECTIVE:To analyze the morphological characteristics of the foramen magnum and occipital condyle by three-dimensional reconstruction measurements,thereby providing anatomical parameters for the far lateral approach to the skull base in clinical practice.METHODS:A total of 673 adult patients(448 males and 225 females)with head and neck CT scans were selected.The age ranged from 20 to 87.The length and width of the foramen magnum were measured.The area and index of the foramen magnum were then calculated by formulas.The length and width of the occipital condyle were measured,as well as the angle between the long and sagittal axis of the occipital condyle(O-S angle),the angle between the line connecting the midpoints of anterior and posterior foramen magnum and the line connecting the midpoint of anterior foramen magnum and the intersection of posterior occipital condyle and lateral foramen magnum(F-O angle),and the angle between the line connecting the midpoints of anterior and posterior foramen magnum and the line connecting the midpoint of anterior foramen magnum and the midpoint of the posterior wall of the hypoglossal canal(F-H angle).The sex and lateral differences of each index were analyzed.RESULTS AND CONCLUSION:There were statistical differences in foramen magnum indexes except between sexes(P>0.05).The indexes of occipital condyle were significantly higher in males than in females(P<0.05)except that the left occipital condyle width in males was lower than that in females(P>0.05).The O-S angle in males was smaller than that in females,and there was a significant difference in the left O-S angle between sexes(P<0.05).There was no statistical difference between right and left F-H angles.Significant differences were observed in occipital condyle length,occipital condyle width,O-S angle,and F-O angle(P<0.05).These findings indicate that the parameters of the foramen magnum and occipital condyle were different in sex and on both sides.For the far lateral and transcondylar approaches,the right approach was relatively safe and exposed to a larger range.The length,width,and area of the foramen magnum,the length of the occipital condyle,and O-S angle in males were larger than those in females.Therefore,the sex difference should be considered in the far lateral approach.