Lu Wei, Xu Jian-Guang, Wang Da-Ping, Gu Yu-Dong
Department of Traumatic and Hand Surgery, Southern Medical University, Shenzhen Hospital, GuangDong, China.
Clin Anat. 2008 Sep;21(6):509-13. doi: 10.1002/ca.20656.
Ipsilateral C7 nerve root transfer or neurotization has been used for the repair of brachial plexus avulsions. In this procedure, the ipsilateral C7 nerve root is used as a donor nerve and is implanted into the damaged nerve of the brachial plexus in order to reinnervate distal muscles. However, this procedure may result in unintended injury to the thoracodorsal nerve, which receives motor fascicles form the cervical nerves of C6, C7, and C8, but mainly from C7. Damage to the thoracodorsal nerve ultimately results in weakness or paralysis of the latissimus dorsi muscle, which it innervates. In the present study, 20 adult cadaveric brachial plexus specimens and 3 fresh specimens were dissected using microscopy. The origin and direction of motor fascicles from the three trunks of the brachial plexus to the thoracodorsal nerve were investigated. Motor fiber counts of C7 and the thoracodorsal nerve were also performed. Several observations can be made: (1) The origin of the thoracodorsal nerve can be divided into three types: Type A, the thoracodorsal nerve originated from the superior and middle trunks; Type B, the thoracodorsal nerve originated from the inferior and middle trunks; and Type C, the thoracodorsal nerve originated from all three trunks. (2) More than 52% of the motor fibers in the thoracodorsal nerve originated in the C7 nerve root. (3) Motor fascicles from C7 to the thoracodorsal nerve were mostly localized in the posterior-internal part of C7 at the trunk-division boundary. In conclusion, we suggest that: (1) Because of variation in the origin of the thoracodorsal nerve, electromyography should be routinely performed intraoperatively during C7 nerve root transfer to determine the origin type and avoid thoracodorsal fascicle injury. (2) Preservation of the posterior-internal part of C7 (selective C7 transfer) can protect thoracodorsal nerve fascicles from damage and prevent postoperative dysfunction of the latissimus dorsi muscle.
同侧C7神经根移位或神经移植已被用于臂丛神经撕脱伤的修复。在该手术中，同侧C7神经根被用作供体神经，并植入臂丛神经的受损神经中，以便重新支配远端肌肉。然而，该手术可能会意外损伤胸背神经，胸背神经接收来自C6、C7和C8颈神经的运动束，但主要来自C7。胸背神经损伤最终会导致其支配的背阔肌无力或麻痹。在本研究中，使用显微镜解剖了20个成人尸体臂丛神经标本和3个新鲜标本。研究了臂丛神经三个干至胸背神经的运动束的起源和方向。还对C7和胸背神经进行了运动纤维计数。可以得出以下几点观察结果：（1）胸背神经的起源可分为三种类型：A型，胸背神经起源于上干和中干；B型，胸背神经起源于下干和中干；C型，胸背神经起源于所有三个干。（2）胸背神经中超过52%的运动纤维起源于C7神经根。（3）从C7至胸背神经的运动束大多位于C7在干部分界处的后内侧部分。总之，我们建议：（1）由于胸背神经起源的变异，在C7神经根移位术中应常规进行术中肌电图检查，以确定起源类型并避免胸背束损伤。（2）保留C7的后内侧部分（选择性C7移位）可保护胸背神经束免受损伤，并防止术后背阔肌功能障碍。
