2020 Volume 48 Issue 3 Pages 168-172
Objective: We evaluated the efficacy of intraoperative motor evoked potential monitoring (MEP) and a novel laser light imaging system to simultaneously visualize visual light and near-infrared fluorescence for indocyanine green angiography (dual-image VA [DIVA]) in aneurysm surgery.
Materials and Methods: Four hundred and five patients who underwent aneurysm surgery were intraoperatively monitored with a direct transcortical electrical stimulation MEP (DCS -MEP), and 104 patients were monitored with a transcranial electrical stimulation MEP (TES-MEP). The TES-MEP threshold was measured before temporary interruption of the cerebral artery or aneurysm clipping as the threshold can fluctuate throughout surgery. Recently, we also performed a number of surgeries using a newly developed laser light in conjunction with the DIVA system.
Results: In 4 cases, the DCS-MEP and TES-MEP signals disappeared during surgery and did not recover. As a result, these patients developed permanent hemiparesis. Two cases developed transient postoperative hemiparesis even though the DCS-MEP and TES-MEP did not change. The MEP monitoring could not detect intraoperative ischemia except for in the pyramidal tract. The laser light, in conjunction with the DIVA system, clearly showed the blood flow in the perforating arteries with the cranial structures in the background.
Conclusions: MEP monitoring is essential in aneurysm surgery, but it cannot predict ischemia apart from that in the pyramidal tract. The laser light, in conjunction with the DIVA system, was useful in avoiding ischemic complications.
