Sheshadri Veena, Bharadwaj Suparna, Chandramouli B A
Department of Anaesthesia, Toronto Western Hospital, Toronto, Canada.
Department of Anaesthesia and Perioperative Medicine, Schulich School of Medicine and Dentistry, London, Ontario, Canada.
Indian J Anaesth. 2016 Aug;60(8):560-5. doi: 10.4103/0019-5049.187784.
Intra-operative identification and preservation of extraocular motor nerves is one of the main goals of surgeries for skull base tumours and this is done by monitoring the extraocular movement (EOM). Intra-operative electromyographic monitoring has been reported, but it is a complex and skilful process. Electrooculography (EOG) is a simple and reliable technique for monitoring EOMs. We aimed to assess the utility of EOG monitoring in preventing extraocular motor nerve dysfunction during skull base surgeries.
In this retrospective cohort study, intra-operative EOG recordings were obtained using disposable needle electrodes placed on the periorbital skin and the polarity of the waves noted for interpretation. Triggered as well as continuous EOG responses were recorded after monopolar electrode stimulation of cranial nerve (CN) during tumour removal which helped the surgeon with careful dissection and avoiding potential nerve injuries.
Of the 11 cases monitored, oculomotor and abducent nerves were identified in all cases, but the trochlear nerve could not be definitively identified. Six patients had no pre- or post-operative extraocular motor nerve dysfunction. The other five patients had pre-existing deficits before surgery, which recovered completely in two, significantly in one, and did not improve in two patients at 3-6 months follow-up.
EOG was found to be a simple and reliable method of monitoring extraocular motor nerves (CNs III and VI) intraoperatively.
术中识别并保留眼外肌神经是颅底肿瘤手术的主要目标之一，这通过监测眼外肌运动（EOM）来实现。术中肌电图监测已有报道，但这是一个复杂且需要技巧的过程。眼电图（EOG）是一种监测眼外肌运动的简单可靠技术。我们旨在评估EOG监测在预防颅底手术中眼外肌神经功能障碍方面的效用。
在这项回顾性队列研究中，使用置于眶周皮肤的一次性针电极获取术中EOG记录，并记录波的极性以供解读。在肿瘤切除过程中，对脑神经（CN）进行单极电极刺激后，记录触发及连续的EOG反应，这有助于外科医生进行仔细解剖并避免潜在的神经损伤。
在监测的11例病例中，所有病例均识别出动眼神经和展神经，但滑车神经无法明确识别。6例患者术前和术后均无眼外肌神经功能障碍。其他5例患者术前存在功能缺损，在3至6个月的随访中，2例完全恢复，1例明显恢复，2例未改善。
发现EOG是术中监测眼外肌神经（动眼神经和展神经）的一种简单可靠方法。
