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Precise MEP monitoring with a reduced interval is safe and useful for detecting permissive duration for temporary
Masahiro Kameda1, Tomohito Hishikawa2, Masafumi Hiramatsu2
1Department of Neurological Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, 2-5-1 Shikata-cho, Kita-ku, Okayama-Shi, Okayama, 700-8558, Japan. mrkameda@gmail.com.
Abstract:
Although temporary clipping of the parent artery is an indispensable technique in clipping surgery for intracranial aneurysms, the permissive duration of temporary clipping is still not well known. The aim of this study is to confirm the safety of precise motor evoked potential (MEP) monitoring and to estimate the permissive duration of temporary clipping for middle cerebral artery (MCA) aneurysm based on precise MEP monitoring results. Under precise MEP monitoring via direct cortical stimulation every 30 seconds to 1 minute, surgeons released a temporary clip and waited for MEP amplitude to recover following severe (>50%) reduction of MEP amplitude during temporary clipping. Precise MEP monitoring was safely performed. Twenty-eight instances of temporary clipping were performed in 42 MCA aneurysm clipping surgeries. Because precise MEP monitoring could be used to determine when to release a temporary clip even with a severe reduction in MEP amplitude due to lengthy temporary clipping, no patients experienced permanent postoperative hemiparesis. Based on logistic regression analysis, if a temporary clip is applied for 312 seconds or more, there is a higher probability of a severe reduction in MEP amplitude. We should therefore release temporary clips after 5 minutes in order to avoid permanent postoperative hemiparesis.
Insights
Precise motor evoked potential (MEP) monitoring safely guides temporary clipping duration during middle cerebral artery aneurysm surgery. Releasing clips within 5 minutes prevents severe MEP reduction and permanent hemiparesis.
Area of Science:
- Neurosurgery
- Neurology
- Medical Monitoring
Background:
- Temporary clipping is crucial for intracranial aneurysm surgery but its safe duration is unknown.
- Monitoring brain function during clipping is essential to prevent neurological deficits.
Purpose of the Study:
- To validate the safety and efficacy of precise motor evoked potential (MEP) monitoring.
- To determine the permissive duration for temporary artery clipping in middle cerebral artery (MCA) aneurysm surgery.
Main Methods:
- Utilized precise MEP monitoring with direct cortical stimulation every 30-60 seconds.
- Temporarily clipped arteries during MCA aneurysm surgery, releasing clips upon >50% MEP amplitude reduction.
- Analyzed 28 temporary clipping instances across 42 surgeries.
Main Results:
- Precise MEP monitoring was performed safely and effectively.
- No permanent postoperative hemiparesis occurred in any patients.
- Logistic regression indicated a higher probability of severe MEP reduction with clipping durations of 312 seconds or longer.
Conclusions:
- Precise MEP monitoring is a safe and reliable method for guiding temporary clipping.
- Temporary clips should be released within 5 minutes to minimize the risk of permanent hemiparesis.
- This study establishes a guideline for safe temporary clipping duration in MCA aneurysm surgery.
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