先天性耳廓畸形的病因和发生机制

耳廓畸形的病因和发病机制仍然不明，报道显示顺产、初生、难产、出生体重>4 000 g为耳形态畸形的高危因素，此类新生儿耳形态畸形发生率明显增高，提示生产时宫内和产道的过分挤压可能为耳畸形的重要致病因素。孕期肝炎也被报道与新生儿耳形态畸形相关，但具体机制不清。此外，耳廓肌肉的先天发育异常也可导致畸形发生，如耳内肌和耳外肌肌肉的缩短会引起局部耳软骨的外突，相反肌肉过长会引起局部沟槽消失导致耳廓平坦。隐耳畸形即与耳上肌和耳横肌肉的短缩有关，而猿耳畸形则与耳横肌的走行方向异常相关。至于耳形态畸形是否有遗传因素目前尚无定论，研究显示正常耳和形态异常耳并无明显的遗传学倾向，个别患儿有家族史但无统计学差异，男女的发生概率基本相同，也无左右侧发生率不等的情况。一般双侧耳廓畸形的发生率明显高于单侧耳畸形，约为后者的两倍。

【参考文献】

[1]Zhao H,Ma L,Qi X,et al.A Morphometric Study of the Newborn Ear and an Analysis of Factors Related to Congenital Auricular Deformities[J].Plast Reconstr Surg,2017,140(1):147-155.10.1097/PRS.0000000000003443

[2]Yotsuyanagi T.Nonsurgical correction of congenital auricular deformities in children older than early neonates[J].Plast Reconstr Surg,2004,114(1):190-191.

[3]Doft M A,Goodkind A B,Diamond S,et al.The Newborn Butterfly Project:A Shortened Treatment Protocol for Ear Molding[J].Plastic and Reconstructive Surgery,2015,135(3):577e-583e.10.1097/PRS.0000000000000999

[4]Yotsuyanagi T,Nihei Y,Shinmyo Y,et al.Stahl's ear caused by an abnormal intrinsic auricular muscle[J].Plast Reconstr Surg,1999,103(1):171-174.