摘要：

目的：通过研究眶下孔（infraorbital foramen, IOF）相对于前鼻棘点（anterior nasal spine, ANS）的位置关系及颏孔（mental foramen, MF）相对于颏前点（pogonion, Pog）的相对位置关系，来为正颌外科手术提供更精准的定位参考。方法：随机选取115例年轻患者的锥形束CT（cone-beam CT）图像。利用Mimics 15.0 软件分析IOF和ANS、MF和Pog之间的相对位置。结果：ANS比IOF低21.40 mm，两者间的水平距离为26.42 mm。MF和Pog间的水平和垂直距离分别为23.57 mm和9.71 mm。以ANS为中心的散点图显示，83%（191/230）的IOF位于半径为30~40 mm的30~45°扇形区域内。以Pog为中心的散点图显示，98%（226/230）的MF位于半径为20~30 mm的45°扇形区域内。结论：为规避直接损伤眶下神经血管束，术者在行上颌骨截骨术时需在不高于ANS点21.40 mm的区域操作。过度地牵引黏骨膜瓣是神经受损的因素之一，尤其是在以ANS为中心的30°扇形区域（半径30~40 mm）和以Pog为中心的45°区域（半径20~30 mm），术者翻瓣和牵拉时应警惕IOF和MF的意外损伤。

关键词: 锥形束CT, 眶下孔, 颏孔, 正颌手术

Abstract:

Objective: To determine the positions of the infraorbital foramen (IOF) relative to the anterior nasal spine (ANS) as well as the mental foramen (MF) relative to the pogonion (Pog), so as to provide reference for orthognathic surgery. Methods: A total of 115 patients with cone-beam CT (CBCT) images were randomly selected. We measured the distances and positional relationships between IOF and ANS, MF and Pog, using Mimics 15.0 software. Results: On average, the ANS was 21.40 mm below the IOF and the horizontal distance between the IOF and ANS was 26.42 mm. The horizontal and vertical distances between MF and Pog was 23.57 mm and 9.71 mm, respectively. Scatter plots centered on ANS showed 83% (191/230) IOF appeared in a 30-45° fan shape ranged in 30-40 mm radius. 98% (226/230) MF occupied a 45° fan shape ranged in 20-30 mm radius in bilateral superior quadrant centered on the Pog. Conclusion: During the maxillary osteotomy, it exists a risk of injuring the infraorbital neurovascular bundle 21.40 mm above the ANS. To avoid IOF injury, excessive flap retraction should be avoided, especially below a 30° fan shape ranged in 30-40 mm radius centered on ANS and a 45° fan shape ranged in 20-30 mm radius centered on Pog. Special attention should be paid when performing flap elevation in this area.

Key words: cone-beam CT, infraorbital foramen, mental foramen, orthognathic surgery

中图分类号: 

• R782