Furukawa Hiroshi, Saito Akira, Mol William, Sekido Mitsuru, Sasaki Satoru, Yamamoto Yuhei
Department of Plastic and Reconstructive Surgery, Graduate School of Medicine, University of Hokkaido at Sapporo, Kita-15 Nishi-7, Kita-Ku, Sapporo, Hokkaido 060-8638, Japan.
J Plast Reconstr Aesthet Surg. 2008;61(3):257-64. doi: 10.1016/j.bjps.2007.01.075. Epub 2007 May 16.
Double innervation of facial mimetic muscles by both facial and hypoglossal nerves after end-to-side neurorrhaphy has not been proven, although facial -hypoglossal end-to-side neurorrhaphy has been used in persistent incomplete facial palsy recently, and has achieved clinical evidences of recovery with rare synkinesis. We established a rat model to compare synkinesis after end-to-end and end-to-side neurorrhaphy techniques between facial and hypoglossal nerves, and confirmed double innervation using retrograde tracers.
Rats were divided into three groups (each consisting of six rats), a facial palsy group (Group A), a facial-hypoglossal end-to-end neurorrhaphy group (Group B), and a facial-hypoglossal end-to-side neurorrhaphy group (Group C). Eight weeks after surgery, synkinesis of the facial mimetic muscles was observed and recorded via video camera. In Group C, post operative, intramuscular injections of retrograde neural tracers (Fast Blue, Diamidino Yellow and DiI) into the facial mimetic muscles were performed to prove double innervation by both the facial and hypoglossal nerves.
In Group B, all rats showed facial palsy. However while eating and drinking, their half of the face showed mass movements (strong contraction of whisker pad muscles, curved nose and eye-closure). In Group C, four rats showed no significant changes however, two rats showed synkinesis of the eyelid while eating and drinking (frequent eye-closure distinguishable from the contralateral normal side). In Group C, retrograde tracers injected in the mimetic muscles were detected in both the facial and hypoglossal motor nuclei in situ of all the rats' brain stem.
This study proved that double innervation of mimetic muscles by both facial and hypoglossal nerves occurs after the end-to-side neurorrhaphy. Double-innervated mimetic muscles around the mouth after hypoglossal-facial end-to-side neurorrhaphy showed less synkinesis than the end-to-end neurorrhaphy.
尽管面神经-舌下神经端侧神经缝合术最近已用于持续性不完全性面神经麻痹，并已获得恢复且极少出现联带运动的临床证据，但面神经和舌下神经对面部表情肌的双重支配在端侧神经缝合术后尚未得到证实。我们建立了一个大鼠模型，以比较面神经和舌下神经端端与端侧神经缝合术后的联带运动，并使用逆行示踪剂证实双重支配。
将大鼠分为三组（每组六只），即面神经麻痹组（A组）、面神经-舌下神经端端神经缝合组（B组）和面神经-舌下神经端侧神经缝合组（C组）。术后八周，通过摄像机观察并记录面部表情肌的联带运动。在C组中，术后向面部表情肌内注射逆行神经示踪剂（快蓝、双脒基黄和碘化丙啶），以证明面神经和舌下神经的双重支配。
在B组中，所有大鼠均表现出面神经麻痹。然而，在进食和饮水时，它们面部的一半出现大量运动（须垫肌肉强烈收缩、鼻子弯曲和闭眼）。在C组中，四只大鼠无明显变化，然而，两只大鼠在进食和饮水时出现眼睑联带运动（频繁闭眼，与对侧正常侧有明显区别）。在C组中，所有大鼠脑干原位的面神经和舌下神经运动核中均检测到注射在表情肌内的逆行示踪剂。
本研究证明，端侧神经缝合术后，面神经和舌下神经对面部表情肌存在双重支配。舌下神经-面神经端侧神经缝合术后口周双重支配的表情肌比端端神经缝合术表现出更少的联带运动。
