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3D visualization of subdural electrode shift as measured at craniotomy reopening. Epilepsy Res 2011 Mar;94(1-2):102-9 PMID: 21334178 PMCID: PMC4329774

Pubmed ID

21334178

Abstract

PURPOSE: Subdural electrodes are implanted for recording intracranial EEG (iEEG) in cases of medically refractory epilepsy as a means to locate cortical regions of seizure onset amenable to surgical resection. Without the aid of imaging-derived 3D electrode models for surgical planning, surgeons have relied on electrodes remaining stationary from the time between placement and follow-up resection. This study quantifies electrode shift with respect to the cortical surface occurring between electrode placement and subsequent reopening.

METHODS: CT and structural MRI data were gathered following electrode placement on 10 patients undergoing surgical epilepsy treatment. MRI data were used to create patient specific post-grid 3D reconstructions of cortex, while CT data were co-registered to the MRI and thresholded to reveal electrodes only. At the time of resective surgery, the craniotomy was reopened and electrode positions were determined using intraoperative navigational equipment. Changes in position were then calculated between CT coordinates and intraoperative electrode coordinates.

RESULTS: Five out of ten patients showed statistically significant overall magnitude differences in electrode positions (mean: 7.2mm), while 4 exhibited significant decompression based shift (mean: 4.7mm), and 3 showed significant shear displacement along the surface of the brain (mean: 7.1mm).

DISCUSSION: Shift in electrode position with respect to the cortical surface has never been precisely measured. We show that in 50% of our cases statistically significant shift occurred. These observations demonstrate the potential utility of complimenting electrode position measures at the reopening of the craniotomy with 3D electrode and brain surface models derived from post-implantation CT and MR imaging for better definition of surgical boundaries.

Author List

LaViolette PS, Rand SD, Ellingson BM, Raghavan M, Lew SM, Schmainda KM, Mueller W

Authors

Peter LaViolette PhD Associate Professor in the Radiology department at Medical College of Wisconsin
Sean Lew MD Chief, Professor in the Neurosurgery department at Medical College of Wisconsin
Manoj Raghavan MD, PhD Professor in the Neurology department at Medical College of Wisconsin
Scott D. Rand MD, PhD Professor in the Radiology department at Medical College of Wisconsin
Kathleen M. Schmainda PhD Professor in the Radiology department at Medical College of Wisconsin




Scopus

2-s2.0-79952455401   21 Citations

MESH terms used to index this publication - Major topics in bold

Adult
Analysis of Variance
Brain Mapping
Craniotomy
Electrodes, Implanted
Electroencephalography
Epilepsy
Female
Humans
Imaging, Three-Dimensional
Magnetic Resonance Imaging
Male
Middle Aged
Reproducibility of Results
Subdural Space
Tomography, X-Ray Computed
Young Adult
jenkins-FCD Prod-256 97250b83e4554f37bec91ca291f44ff4aedcc508