Bone flap elevation for intracranial EEG monitoring: technical note

Yasunori Nagahama; Brian J Dlouhy; Daichi Nakagawa; Janina Kamm; David Hasan; Matthew A Howard III; Hiroto Kawasaki

doi:10.3171/2017.3.JNS163109

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Bone flap elevation for intracranial EEG monitoring: technical note

Journal article

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Peer reviewed

Bone flap elevation for intracranial EEG monitoring: technical note

Yasunori Nagahama, Brian J Dlouhy, Daichi Nakagawa, Janina Kamm, David Hasan, Matthew A Howard III and Hiroto Kawasaki

Journal of neurosurgery, Vol.129(1), pp.182-187

07/2018

DOI: 10.3171/2017.3.JNS163109

PMID: 28946179

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Abstract

Intracranial electroencephalography (iEEG) provides invaluable information in determining seizure focus and spread due to its high spatial and temporal resolution, which are not afforded by noninvasive studies. Electrodes of various types (e.g., grid, strip, and depth electrodes) and configurations are often used for optimum coverage of suspected areas of seizure onset and propagation. Given the fixed intracranial volume and added mass effect from placement of cortical electrodes, brain edema and postoperative deficits can occur.The authors describe a simple, inexpensive, and highly effective technique of bone flap replacement using standard titanium plates to expand the intracranial volume and minimize risks of brain compression and intracranial hypertension. Rectangular titanium plates are bent and placed in a way that secures the bone flap in a slightly elevated position relative to the adjacent calvaria during iEEG monitoring. The authors evaluated the degree of bone flap elevation and amount of volume created using this technique in 3 iEEG cases. They then compared these results with the bone flap elevation and volume created using linear titanium plates, a method they had used previously. The use of rectangular plates produced on average 6.6 mm of bone flap elevation, compared with only 1.8 mm of bone flap elevation with the use of linear plates, resulting in a statistically significant 261% increase in bone flap elevation (p ≤ 0.001). The authors suggest that rectangular plates may provide stronger resistance to scalp tension after myocutaneous skin closure compared with the linear plates and that subsidence of the bone flap likely occurred with the use of linear plates. In summary, the described technique utilizing rectangular plates creates significantly increased bone flap elevation compared with a similar method using linear plates, and it may reduce the risk of neurological deficits related to intracranial electrode placement.

Details

Title: Subtitle: Bone flap elevation for intracranial EEG monitoring: technical note
Creators: Yasunori Nagahama - Departments of 1Neurosurgery and
Brian J Dlouhy - Departments of 1Neurosurgery and
Daichi Nakagawa - 2Department of Neurosurgery, University of Tokyo, Japan
Janina Kamm - 3Neurology, University of Iowa Hospitals and Clinics, Iowa City, Iowa; and
David Hasan - Departments of 1Neurosurgery and
Matthew A Howard III - Departments of 1Neurosurgery and
Hiroto Kawasaki - Departments of 1Neurosurgery and
Resource Type: Journal article
Publication Details: Journal of neurosurgery, Vol.129(1), pp.182-187
DOI: 10.3171/2017.3.JNS163109
PMID: 28946179
NLM abbreviation: J Neurosurg
ISSN: 0022-3085
eISSN: 1933-0693
Language: English
Date published: 07/2018
Academic Unit: Roy J. Carver Department of Biomedical Engineering; Neurology; Stead Family Department of Pediatrics; Iowa Neuroscience Institute; Neurosurgery; Otolaryngology
Record Identifier: 9984020653502771

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