Objective

We demonstrate the advantages and safety of long, intraorbitally-placed needle electrodes, compared to standard-length subdermal electrodes, when recording lateral rectus electromyography (EMG) during intracranial surgeries.

Methods

Insulated 25 mm and uninsulated 13 mm needle electrodes, aimed at the lateral rectus muscle, were placed in parallel during 10 intracranial surgeries, examining spontaneous and stimulation-induced EMG activities. Postoperative complications in these patients were reviewed, alongside additional patients who underwent long electrode placement in the lateral rectus.

Results

In 40 stimulation-induced recordings from 10 patients, the 25 mm electrodes recorded 6- to 26-fold greater amplitude EMG waveforms than the 13 mm electrodes. The 13 mm electrodes detected greater unwanted volume conduction upon facial nerve stimulation, typically exceeding the amplitude of abducens nerve stimulation. Except for one case with lateral canthus ecchymosis, no clinical or radiographic complications occurred in 36 patients (41 lateral rectus muscles) following needle placement.

Conclusions

Intramuscular recordings from long electrode in the lateral rectus offers more reliable EMG monitoring than 13 mm needles, with excellent discrimination between abducens and facial nerve stimulations, and without significant complications from needle placement.

Significance

Long intramuscular electrode within the orbit for lateral rectus EMG recording is practical and reliable for abducens nerve monitoring.

中文翻译：

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深眶内针电极优化的术中外直肌肌电图记录

客观的

在颅内手术期间记录侧直肌肌电图 (EMG) 时，与标准长度的皮下电极相比，我们展示了长的、眶内放置的针状电极的优势和安全性。

方法

在 10 次颅内手术期间，将针对外直肌的绝缘 25 mm 和非绝缘 13 mm 针电极平行放置，检查自发和刺激诱导的 EMG 活动。回顾了这些患者的术后并发症，以及在外直肌中接受长电极放置的其他患者。

结果

在 10 名患者的 40 次刺激诱导记录中，25 mm 电极记录的 EMG 波形幅度是 13 mm 电极的 6 到 26 倍。13 mm 电极在面神经刺激时检测到更大的不需要的体积传导，通常超过外展神经刺激的幅度。除 1 例外眦瘀斑外，36 例患者（41 块外直肌）置针后均未出现临床或影像学并发症。

结论

来自外直肌长电极的肌内记录提供比 13 毫米针更可靠的 EMG 监测，在外展肌和面神经刺激之间具有出色的辨别力，并且针放置没有明显的并发症。

意义

用于外直肌肌电图记录的轨道内长肌内电极对于外展神经监测是实用且可靠的。