Gavid M, Mayaud A, Timochenko A, Asanau A, Prades J M
Laboratoire d'Anatomie, Université Jean Monnet, Saint-Etienne, France.
Service d'Oto-Rhino-Laryngologie, CHU Saint-Etienne, Saint-Etienne, France.
Surg Radiol Anat. 2016 Oct;38(8):917-22. doi: 10.1007/s00276-016-1658-1. Epub 2016 Mar 8.
The aim of this study was to determine the existence and the frequency of communicating branches between the spinal accessory nerve (SAN) and the C2, C3 and C4 roots of the cervical plexus. The present study also aimed to elucidate whether these branches contain motor fibers or not. Dissection of the cervical region was performed on twelve adult cadavers. A powered operating microscope was necessary to dissect the SAN and its branches and also to dissect C2, C3 and C4 nerve branches. In a second step, data from 13 patients who underwent 25 modified neck dissections under trapezius muscle's monitoring were collected. At the end of surgery, intraoperative stimulation on the SAN, C2, C3 and C4 nerve branches was performed. Registered potentials in the three parts of the trapezius muscle, using the NIM Medtronic system, were analyzed. During cadaver dissection, 18 (78 %) communicating branches were identified between the SAN and C2, 11 (48 %) between the SAN and C3, 12 (52 %) between the SAN and C4. Intraoperative stimulation of the SAN and its branch for the trapezius muscle provided a significant electroneurographic response in the three parts of the trapezius muscle in all subjects. Intraoperative stimulation of C3 led to recordable contractions of the trapezius muscle in 5 (20 %) modified neck surgeries, stimulation of C4 led to recordable contractions during 5 (20 %) modified neck dissections. One case of contraction was recorded after intraoperative stimulation of C2 (7 %). Although we were able to identify at least one communicating branch between the SAN and the roots of the cervical plexus in each cadaver dissection, the cervical plexus is not always involved in trapezius motor innervation. Intraoperative electroneurography demonstrated that a motor input from the cervical plexus to the trapezius muscle was provided in only 32 % of cases. Therefore, SAN trunk and C3-C4 roots should be carefully preserved during modified neck dissection to protect trapezius and shoulder functions.
本研究的目的是确定副神经（SAN）与颈丛的C2、C3和C4神经根之间交通支的存在情况及出现频率。本研究还旨在阐明这些分支是否含有运动纤维。对12具成年尸体的颈部区域进行了解剖。解剖SAN及其分支以及C2、C3和C4神经分支时需要使用电动手术显微镜。第二步，收集了13例在斜方肌监测下接受25次改良颈清扫术患者的数据。手术结束时，对SAN、C2、C3和C4神经分支进行了术中刺激。使用美敦力NIM系统分析了斜方肌三个部位记录到的电位。在尸体解剖过程中，发现SAN与C2之间有18条（78%）交通支，SAN与C3之间有11条（48%），SAN与C4之间有12条（52%）。对SAN及其支配斜方肌的分支进行术中刺激时，所有受试者斜方肌的三个部位均出现了明显的神经电图反应。术中刺激C3时，在5例（20%）改良颈清扫术中导致斜方肌出现可记录的收缩，刺激C4时，在5例（20%）改良颈清扫术中导致斜方肌出现可记录的收缩。术中刺激C2后有1例（7%）出现收缩记录。尽管在每次尸体解剖中我们都能在SAN与颈丛神经根之间识别出至少一条交通支，但颈丛并不总是参与斜方肌的运动神经支配。术中神经电图显示，只有32%的病例有来自颈丛至斜方肌的运动输入。因此，在改良颈清扫术中应小心保留SAN主干和C3 - C4神经根，以保护斜方肌和肩部功能。
