第一部分 上睑运动的力学机制初步探讨

背景：汉族人中双侧重睑者所占比例约为1/2^[1]。近年来，由于大众审美对重睑的偏爱，许多求美者想要通过外科手术改变原有的上睑外观。上睑作为眼球的保护结构，又执行眼睑的开合功能，其内部的解剖结构和运动时的力学机制都十分精细，并且在单睑与重睑之间存在着较大差异。明确上睑运动的力学机制及其对上睑外观的影响，对切开法重睑成形术具有非常重要的临床指导意义。

目的：探讨上睑运动的力学机制，明确其对上睑外观产生的影响，为重睑成形术的术式改进提供理论依据。

方法：1.通过主题词和关键词检索，在PubMed、中国知网、万方、维普等数据库搜集与人类上睑解剖有关的文献，对上睑解剖层次做出总结梳理。2.通过提出上睑“运动复合体”和“相对静止区”概念，对上睑运动的力学机制与外在形态之间的关系进行探讨。3.将探讨所得出的理论结论运用于分析自发性上睑外观变化现象以及两种经典切开法重睑成形术。

结果：1.人类上睑的解剖层次复杂，且在单睑与重睑中存在较大差异。2.睁眼过程中，上睑各层结构可依其运动趋势划分为“运动复合体”与“相对静止区”，两区交界处产生的剪切力及其分布水平对睁眼后的上睑外观产生决定性影响。3.在重睑成形术中，睑板前眼轮匝肌彻底去除或单纯地完全保留，都不能很好地模拟天然重睑运动的力学机制，手术效果具有一定的局限性。

结论：单睑与重睑的解剖结构不同，运动的力学机制也不同，重睑成形术只有同时实现结构仿生和力学重建这两个目标，才能塑造出自然美观的重睑。

第二部分 重睑成形术中结构仿生与力学重建技术的应用

目的：探讨在一种在重睑成形术中通过结构仿生与力学重建技术来塑造自然重睑的手术方式,并通过术后随访和结果分析，评价该术式的可行性。

方法：将2015年06月至2019年10月于北京协和医学院中国医学科学院整形外科医院整形九科行切开法重睑成形术的求美者纳入研究。术前所有求美者均签署手术知情同意书，由我科同一医师采取相同术式进行手术，并在术前、术中拍照记录，术后进行门诊、电话或网络随访。手术中所应用的创新主要包括：①眼轮匝肌深层释放，即分离并去除切口下唇至睑缘的全部眼轮匝肌深筋膜；②眼轮匝肌浅层释放，即沿切口下唇真皮与眼轮匝肌间隙向下分离约1mm；③眼轮匝肌高位悬吊，即将切口下唇经释放后的眼轮匝肌拉伸变薄并高位固定于上睑提肌腱膜。

结果：162名求美者被纳入研究，术后一周左右拆线，手术切口全部一期愈合。获得术后至少6个月随访的求美者共45名，随访时间最长32个月，平均12个月。在该部分求美者中：对手术效果非常满意的36人、基本满意的7人，不满意的2人；全部求美者术后重睑线弧度流畅，睫毛轻度上翘，无眼睑闭合不全或上睑迟滞现象，睁眼无“肉条”现象，闭眼时切口无凹陷或台阶样外观，瘢痕隐蔽；术后双侧重睑轻度不对称者3人，单侧重睑消失者2人，均经再次手术修复；术后早期出现轻度睑缘外翻者2人，未经处理。

结论：在切开法重睑成形术中，将睑板前眼轮匝肌释放后高位悬吊于上睑提肌腱膜，可以模拟天然重睑的解剖结构和力学传递特点，实现结构仿生和力学重建，塑造出自然美观的重睑，且求美者术后满意度较高，是一种值得推广的术式。

Part I  Preliminary investigation on the kinematics mechanism of upper eyelid movement

Background: The proportion of bilateral double eyelids in Han Chinese is about 1/2 ^[1]. In recent years, due to the public’s aesthetic preference for double eyelids, many beauty pursuers want to change the original upper eyelid appearance through surgery. Serving as the protective structure of the eyeball, the upper eyelid performs the opening and closing function, with exquisite internal anatomical structure and complex kinematics mechanism, which are of great differences from those of single eyelid. Thus, clarifying the kinematics mechanism of upper eyelid and its relationship with appearance is of very important clinical guiding significance for incisional blepharoplasty.

Objective: This article is to investigate the kinematics mechanism of upper eyelid, and to clarify its relationship with the upper eyelid external-shape and double eyelid plasty.

Methods: 1.Literature related to human upper eyelid anatomy was collected in PubMed, CNKI, Wanfang, Vepsa and other databases through keyword and MeSH，and the anatomical levels of the upper eyelid were summarized.  2. By proposing the concept of "motor complex" and "relative static zone" of the upper eyelid, the relationship between the kinematics mechanism and external shape of the upper eyelid is discussed.  3. The theoretical conclusions are applied to analyze the spontaneous changes in the appearance of the upper eyelid and the two classic incisional blepharoplasty.

Results: 1. The anatomical level of the upper eyelid is complex, and there are great differences between single eyelid and double eyelid.  2. During the process of opening eyes, each anatomical layer of the upper eyelid can be divided into "motor complex" and "relative static zone" according to its movement trend. The shear force generated at the junction of the two zones and its distribution level have a decisive influence on the appearance of the upper eyelid after opening eyes.  3. In blepharoplasty, no matter complete removal or complete retention of the orbicularis oculi muscle in front of the tarsus, they can’t simulate the kinematics mechanism of natural double eyelid movement well, and the surgical effect has certain limitations.

Conclusion: The anatomical structure and the kinematics mechanism have great differences between single eyelid and double eyelid. The blepharoplasty can create a natural and beautiful double eyelid only by realizing the two goals of structural bionics and kinematics reconstruction at the same time.

Part II Application of structural bionics and kinematics reconstruction technique in blepharoplasty

Objective: To explore the surgical technique of shaping natural double eyelid by structural bionics and kinematics reconstruction in blepharoplasty, and to evaluate the feasibility of the surgical technique through postoperative follow-up and result analysis. 

Methods: Beauty pursuers who underwent incisional blepharoplasty at the Nine Department of Plastic Surgery Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College from June 2015 to October 2019 were included in the study. All beauty pursuers signed the informed consent form before operation. The same physician performed the same operation, and photos of these beauty pursuers were taken and collected before and duringoperation. After operation, we have been carrying out outpatient, telephone or Internet follow-up.The innovations applied in these operations mainly include: ① deep release of the orbicularis oculi muscle, that is, separation and removal of all the deep fascia of the orbicularis oculi muscle from the lower lip of the incision to the eyelid margin. ② superficial release of the orbicularis oculi muscle, that is, separation of about 1 mm downward along the interspace between the the dermis and orbicularis oculi muscle of the lower lip of the incision. ③ high suspension of the orbicularis oculi muscle, that is, stretching and thinning of the orbicularis oculi muscle of the lower lip of the incision after release and high fixation to the levator aponeurosis.

Results: 162 beauty pursuers were included in the study. The suture was removed about one week after operation. One-stage incision healing were achieved in all beauty pursuers. A total of 45 beauty pursuers were followed up for at least 6 months after surgery, with a maximum follow-up time of 32 months and an average one of 12 months. Among the beauty pursuers in this part, 36 were very satisfied with the surgical results ,7 were basically satisfied and and 2 were dissatisfied. All the beauty pursuers had smooth curve of double eyelid line, mild upturned eyelashes. There is no hypophasis or upper eyelid hysteresis, no "meat strip" phenomenon when opening eyes, no depression or step-like appearance of incision when closing eyes. The scar is concealed. 3 had mild asymmetry of bilateral double eyelids after surgery. 2 had disappearance of unilateral double eyelids, which were repaired by reoperation. 2 had mild ectropion of eyelid margin in the early postoperative period, without treatment.

Conclusion: Suspension of the orbicularis oculi muscle in front of the tarsus on the levator aponeurosis can simulate the anatomical structure and kinematics transmission of the natural double eyelid, realize structural bionics and kinematics reconstruction, shape the natural beautiful double eyelid, and has a high postoperative satisfaction, which is a new surgical method worth popularizing.