视神经管周围结构解剖的实验研究

目的 了解视神经管周围结构的解剖并为临床视神经管减压术及鼻窦手术提供解剖学依据.方法 实验研究.(1)成人干性颅骨标本50个,观察和测量筛窦和蝶窦的形态和大小;(2)甲醛溶液固定的成年湿性头颅标本15个,观察和测量蝶窦中部外侧壁与颈内动脉的距离、眼动脉起始处与颈内动脉的夹角,测量视神经颅内段的长度、视神经于视交叉前方之间的夹角、视神经颅内段颅口处两侧视神经内侧缘之间的距离,测量眼动脉在视神经管内的长度和直径;(3)选取6例经甲醛溶液防腐固定的完整成年无明显病变的成年湿性头颅标本,应用CT对筛、蝶窦进行轴位和冠状位扫描,观察视神经管与筛、蝶窦的关系;然后将CT扫描后的湿性头颅标本利用工业用钢锯行筛、蝶窦的断面(6例)、水平断面(3例)、冠状断面(3例)解剖,层厚均为6 mm.将筛窦、蝶窦、视神经管的CT扫描图像和相对应的解剖断面标本进行对比、观察.采用SPSS 13.0统计学软件进行数据处理.男性与女性湿性颅骨标本的测量值比较,采用两组独立样本的t检验.结果 全筛窦前后径(39.02±4.89)mm,前部横径(12.26±2.12)mm,前筛窦上下径(11.89±2.56)mm;蝶窦前后径(24.08±4.87)mm,蝶窦中部外侧壁与颈内动脉的距离(1.23±0.56)mm;眼动脉起始处与颈内动脉的夹角54.33°±7.89°;视神经颅内段的长度(9.91±2.89)mm,两侧视神经于视交叉前方之间的夹角59.89°±4.79°,视神经颅口处两侧视神经内侧缘之间的距离(14.26±3.23)mm;眼动脉在管内段的长度(5.38±1.87)mm,眼动脉外径(2.18±0.37)mm.男性与女性间的视神经颅内段长度(t=0.25)、两侧视神经于视交叉前方之间的夹角(t=0.71)、视神经颅口处两侧视神经内侧缘之间的距离(t=0.57)、蝶窦中部外侧壁与颈内动脉的距离(t=0.29)、眼动脉起始处与颈内动脉的夹角(t=0.99)、眼动脉在视神经管内段的长度(t=0.50)、眼动脉外径(t=0.52)测量值比较,差异均无统计学意义(P>0.05).结论 (1)切开视神经管内侧壁时,在蝶窦内切开的深度不宜超过13 mm,否则有可能损伤颈内动脉并引起大出血;(2)在进行视神经管减压术时,穿破前部筛窦的左右深度不宜超过15 mm,上下不宜超过12 mm,否则易穿破到对侧筛窦或向上穿破颅底进入颅内;(3)应特别注意保护眼动脉,防止眼部缺血和失明.

Experimental study on anatomy of adjacent structures of the optic canal

Objective To provide microanatomical data for optic canal decompression surgery or paranasal sinus surgery through anatomaical study on adjacent structures of the optic canal Methods It was a experimental study. (1)Fifty dry cadaveric adult heads (100 sides) were dissected. The shapes and sizes of ethmoid sinus and sphenoid sinus were observed and measured. (2) The distance between the mid-point of the lateral wall of the sphenoid sinus and the internal carotid artery, the angle between the initial section of the ophthalmic artery and internal carotid artery were observed and measured under both naked eye and microscope. The distance between the medial margin of bilateral optic nerve at the frontal outlet were measured on 15 formalin-fixed wet cadaveric adult heads. The relationships between the optic canal and ethmoid sinus and spbenoid sinus were observed on 6 formalin-fixed cadaveric adult heads by CT scanning;the morphological features and adjacent structures were contrasted and observed on 6 ice-frozen cadaveric head specimens by CT scanning and corresponding applied sectional anatomy. Results The anterior-posterior diameter of total ethmoid sinus was( 39. 02 ± 4. 89 ) mm. The horizontal diameter of anterior ethmoid sinus was ( 12. 26 ± 2. 12)mm. The superior-inferior diameter of anterior ethmoid sinus was ( 11.89 ± 2. 56) mm. The anterior-posterior diameter of sphenoid sinus was ( 24. 08 ± 4. 87 ) mm. The distance between the middle part of the lateral wall of sphcnoid sinus and internal carotid artery was ( 1.23 ± 0. 56 ) mm;the angle between the initial section of ophthalmic artery and internal carotid artery was 54. 33°±7.89°. The distance between the medial margin of bilateral optic nerve at the frontal outlet was ( 14. 26 ± 3.23 ) mm. Conclusions (1)When the medial wail of the optic canal is opened inside the sphenoid sinus, the depth shouldn't exceed 13 mm, otherwise it may damage the internal carotid artery and cause severe bleeding even death. (2)The depth should be less than 15 mm and the superior-inferior diameter should be less than 12 nun inside the anterior ethmoid sinus, otherwise the opposite ethmoid sinus or frontal base may be opened aocidently. (3) The ophthalmic artery should be specifically protceted in order not to cause ocular ischemia and blindness.