臂丛撕脱伤患者同侧膈神经诱发电位的研究

Electrophysiological evaluation of phrenic nerve function after brachial plexus avulsion injury

目的研究臂丛撕脱伤患者同侧膈神经的功能状态，为临床选用膈神经移位治疗臂丛撕脱伤提供依据。方法测定１００例臂丛神经撕脱伤膈肌诱发电位的潜伏期、波幅，并对其功能进行评价。将表面电极置在胸锁乳突肌后缘，在平环状软骨水平进行电刺激，于腋前线水平在第７、８肋间记录肌肉诱发电位。同时在膈神经移位术中取一段膈神经，观察其病理变化。结果诱发电位的资料证实，有１８例膈神经存在不同程度的损伤，其中１１例为完全损伤，７例为不全损伤。病理学观察发现膈神经部分损伤时，光镜下见神经纤维部分髓鞘崩解，髓鞘之间散在性地分布着瘢痕化组织。膈神经完全损伤时，可见神经髓鞘崩解，髓鞘之间布满瘢痕化组织。结论１００例臂丛撕脱伤中１８％的膈神经有损伤，其中７％为不全损伤。应重视这部分病例中膈神经的部分损伤，以便改进手术方法。

Objective To investigate phrenic nerve function after brachial plexus avulsion injury by electrophysiological examination. Methods 100 cases of brachial plexus avulsion injuries were studied. With stimulatory surface electrodes placed at the posterior border of the sternoclaidomastoid muscle at the level of the upper border of the thyroid cartilage, the diaphragmatic evoked potentials were recorded using surface electrodes placed over the left and right side of the seventh intercostal space and the left and right side of the eighth intercostal space. The phrenic nerve function was then evaluated by latent periods and amplitudes of the evoked potentials. During the operations of phrenic nerve transfer, a segment of phrenic nerve was harvested, and its pathological changes were observed with osmic acid staining. Results Phrenic nerve injuries were found in 18 of 100 cases of brachial plexue avulsion injuries. Among them, 11 cases were complete injuries, 7 cases partial injuries. In complete lesions of phrenic nerve, myelinated fibers of the nerve were found to be replaced by scar tissue under electron microscope. In partial lesions, some myelinated fibers disappeared, some still remained intact. Conclusions Phrenic nerve was injured in 18 percent cases of brachial plexue avulsion injuries. Among them, complete injury amounted to 11 percent, partial injury 7 percent. Attention should be paid to partial injury of phrenic nerve for the sake of improving surgical outcome.