Clinically silent magnetic resonance imaging findings after subdural strip electrode implantation

Clinical article

Restricted access

Object

Subdural strip electrodes (SSEs) are often used as part of the workup in patients being considered for epilepsy surgery. To assess for complications or to confirm electrode placement, postoperative imaging is often performed. Imaging performed with the electrodes in situ is limited by streak artifact on CT and susceptibility artifact on MR imaging. Therefore, the first opportunity for high-quality postoperative imaging is following explantation of electrodes. There is no data available to determine what would be the expected MR imaging appearance following insertion of SSE. The purpose of this study is to describe the MR imaging findings in asymptomatic patients who underwent insertion of SSEs.

Methods

Twenty consecutive patients who underwent SSE insertion were studied. Within 24 hours after removal of the electrodes, each patient underwent MR imaging that included axial T2-weighted, gradient echo, diffusion weighted, and coronal FLAIR sequences. No significant symptoms were reported by any of the patients. The studies were reviewed by an experienced, blinded neuroradiologist and categorized.

Results

Of the 20 patients studied, 11 were female (mean age 36 years). Clinically silent postexplantation MR imaging abnormalities were found in all patients: subdural hematomas in 7 (35%), cortical contusions in 5 (25%), local edema in 5 (25%), trans–bur hole cortical herniation in 5 (25%), subdural hygromas in 2 (10%), and pneumocranium in 4 (20%). The MR imaging abnormalities were subdivided into 2 types: Type A, abnormalities related to the site of electrode insertion; and Type B, abnormalities related to the location of the electrodes. The most common location for a Type A abnormality was occipitotemporal, with cortical contusions occurring in this location in 18% of cases, local edema in 24%, and trans–bur hole herniation in 24%. The next most common location was frontal, with cortical contusions found in this location in 10% of cases, local edema in 5% and trans–bur hole herniation in 5%. The most common Type B abnormality was a subdural hematoma, followed by pneumocranium and subdural hygroma.

Conclusions

Clinically silent MR imaging abnormalities are common following SSE placement. Knowledge of these findings would be of assistance in interpreting MR imaging results in patients being assessed for complications.

Abbreviations used in this paper: EEG = electroencephalography; SSE = subdural strip electrode.
Article Information

Contributor Notes

Address correspondence to: David A. Steven, M.D., M.P.H., F.R.C.S.C., Division of Neurosurgery, University Hospital, London Health Sciences Centre, 339 Windermere Road, Room A10-323, London, Ontario, Canada N6A 5A5. email: david.steven@lhsc.on.ca.Please include this information when citing this paper: published online July 24, 2009; DOI: 10.3171/2009.6.JNS09228.

© AANS, except where prohibited by US copyright law.

Headings
References
  • 1

    Adelson PDBlack PMMadsen JRKramer URockoff MARiviello JJ: Use of subdural grids and strip electrodes to identify a seizure focus in children. Pediatr Neurosurg 22:1741801995

    • Search Google Scholar
    • Export Citation
  • 2

    Awad IARosenfeld JAhl JHahn JFLuders H: Intractable epilepsy and structural lesions of the brain: mapping, resection strategies, and seizure outcome. Epilepsia 32:1791861991

    • Search Google Scholar
    • Export Citation
  • 3

    Bancaud JAngelergues RBernouilli CBonis ABordas-Ferrer MBresson M: Functional stereotaxic exploration (SEEG) of epilepsy. Electroencephalogr Clin Neurophysiol 28:85861970

    • Search Google Scholar
    • Export Citation
  • 4

    Bancaud JAngelergues RBernouilli CBonis ABordas-Ferrer MBresson M: [Functional stereotaxic exploration (stereo-electroencephalography) in epilepsies.]. Rev Neurol (Paris) 120:4481969. (Fr)

    • Search Google Scholar
    • Export Citation
  • 5

    Behrens ESchramm JZentner JKonig R: Surgical and neurological complications in a series of 708 epilepsy surgery procedures. Neurosurgery 41:1101997

    • Search Google Scholar
    • Export Citation
  • 6

    Behrens EZentner Jvan Roost DHufnagel AElger CESchramm J: Subdural and depth electrodes in the presurgical evaluation of epilepsy. Acta Neurochir (Wien) 128:84871994

    • Search Google Scholar
    • Export Citation
  • 7

    Brekelmans GJvan Emde Boas WVelis DNLopes da Silva FHvan Rijen PCvan Veelen CW: Comparison of combined versus subdural or intracerebral electrodes alone in presurgical focus localization. Epilepsia 39:129013011998

    • Search Google Scholar
    • Export Citation
  • 8

    Burneo JGSteven DAMcLachlan RSParrent AG: Morbidity associated with the use of intracranial electrodes for epilepsy surgery. Can J Neurol Sci 33:2232272006

    • Search Google Scholar
    • Export Citation
  • 9

    Cohen-Gadol AASpencer DD: Use of an anteromedial subdural strip electrode in the evaluation of medial temporal lobe epilepsy. Technical note. J Neurosurg 99:9219232003

    • Search Google Scholar
    • Export Citation
  • 10

    Davis LMSpencer DDSpencer SSBronen RA: MR imaging of implanted depth and subdural electrodes: is it safe?. Epilepsy Res 35:95981999

    • Search Google Scholar
    • Export Citation
  • 11

    Diehl BLuders HO: Temporal lobe epilepsy: when are invasive recordings needed?. Epilepsia 41:Suppl 3S61S742000

  • 12

    Engel J Jr: Surgical treatment of the epilepsies ed 2New YorkRaven Press1993

  • 13

    Fountas KNSmith JR: Subdural electrode-associated complications: a 20-year experience. Stereotact Funct Neurosurg 85:2642722007

  • 14

    Gonzalez-Feria LGarcia-Marin V: Sub-occipital approach for implantation of recording multi-electrodes over the medial surface of the temporal lobe. Acta Neurochir Suppl (Wien) 58:1901921993

    • Search Google Scholar
    • Export Citation
  • 15

    Hamer HMMorris HHMascha EJKarafa MTBingaman WEBej MD: Complications of invasive video-EEG monitoring with subdural grid electrodes. Neurology 58:971032002

    • Search Google Scholar
    • Export Citation
  • 16

    Jayakar PDuchowny MResnick TJAlvarez LA: Localization of seizure foci: pitfalls and caveats. J Clin Neurophysiol 8:4144311991

    • Search Google Scholar
    • Export Citation
  • 17

    Lee WSLee JKLee SAKang JKKo TS: Complications and results of subdural grid electrode implantation in epilepsy surgery. Surg Neurol 54:3463512000

    • Search Google Scholar
    • Export Citation
  • 18

    Lesser RPLuders HKlem GDinner DSMorris HHHahn JF: Extraoperative cortical functional localization in patients with epilepsy. J Clin Neurophysiol 4:27531987

    • Search Google Scholar
    • Export Citation
  • 19

    Luders HHahn JLesser RPDinner DSMorris HH IIIWyllie E: Basal temporal subdural electrodes in the evaluation of patients with intractable epilepsy. Epilepsia 30:1311421989

    • Search Google Scholar
    • Export Citation
  • 20

    Mocco JKomotar RJLadouceur AKZacharia BEGoodman RRMcKhann GM II: Radiographic characteristics fail to predict clinical course after subdural electrode placement. Neurosurgery 58:1201252006

    • Search Google Scholar
    • Export Citation
  • 21

    Nair DRBurgess RMcIntyre CCLüders H: Chronic subdural electrodes in the management of epilepsy. Clin Neurophysiol 119:11282008

    • Search Google Scholar
    • Export Citation
  • 22

    Olivier AGloor PQuesney LFAndermann F: The indications for and the role of depth electrode recording in epilepsy. Appl Neurophysiol 46:33361983

    • Search Google Scholar
    • Export Citation
  • 23

    Onal COtsubo HAraki TChitoku SOchi AWeiss S: Complications of invasive subdural grid monitoring in children with epilepsy. J Neurosurg 98:101710262003

    • Search Google Scholar
    • Export Citation
  • 24

    Pillay PKBarnett GAwad I: MRI-guided stereotactic placement of depth electrodes in temporal lobe epilepsy. Br J Neurosurg 6:47531992

    • Search Google Scholar
    • Export Citation
  • 25

    Salanova VMorris HH IIIVan Ness PCLuders HDinner DWyllie E: Comparison of scalp electroencephalogram with subdural electrocorticogram recordings and functional mapping in frontal lobe epilepsy. Arch Neurol 50:2942991993

    • Search Google Scholar
    • Export Citation
  • 26

    Silberbusch MARothman MIBergey GKZoarski GHZagardo MT: Subdural grid implantation for intracranial EEG recording: CT and MR appearance. AJNR Am J Neuroradiol 19:108910931998

    • Search Google Scholar
    • Export Citation
  • 27

    Simon SLTelfeian ADuhaime AC: Complications of invasive monitoring used in intractable pediatric epilepsy. Pediatr Neurosurg 38:47522003

    • Search Google Scholar
    • Export Citation
  • 28

    So NGloor PQuesney LFJones-Gotman MOlivier AAndermann F: Depth electrode investigations in patients with bitemporal epileptiform abnormalities. Ann Neurol 25:4234311989

    • Search Google Scholar
    • Export Citation
  • 29

    Spencer SS: Depth electroencephalography in selection of refractory epilepsy for surgery. Ann Neurol 9:2072141981

  • 30

    Spencer SSSpencer DDWilliamson PDMattson R: Combined depth and subdural electrode investigation in uncontrolled epilepsy. Neurology 40:74791990

    • Search Google Scholar
    • Export Citation
  • 31

    Steven DAAndrade-Souza YMBurneo JGMcLachlan RSParrent AG: Insertion of subdural strip electrodes for the investigation of temporal lobe epilepsy. Technical note. J Neurosurg 106:110211062007

    • Search Google Scholar
    • Export Citation
  • 32

    Swartz BERich JRDwan PSDeSalles AKaufman MHWalsh GO: The safety and efficacy of chronically implanted subdural electrodes: a prospective study. Surg Neurol 46:87931996

    • Search Google Scholar
    • Export Citation
  • 33

    Thadani VMWilliamson PDBerger RSpencer SSSpencer DDNovelly RA: Successful epilepsy surgery without intracranial EEG recording: criteria for patient selection. Epilepsia 36:7151995

    • Search Google Scholar
    • Export Citation
  • 34

    Wiebe SBlume WTGirvin JPEliasziw M: A randomized, controlled trial of surgery for temporal-lobe epilepsy. N Engl J Med 345:3113182001

    • Search Google Scholar
    • Export Citation
  • 35

    Wieser HG: ILAE Commission Report. Mesial temporal lobe epilepsy with hippocampal sclerosis. Epilepsia 45:6957142004

  • 36

    Wiggins GCElisevich KSmith BJ: Morbidity and infection in combined subdural grid and strip electrode investigation for intractable epilepsy. Epilepsy Res 37:73801999

    • Search Google Scholar
    • Export Citation
  • 37

    Wyler AROjemann GALettich EWard AA Jr: Subdural strip electrodes for localizing epileptogenic foci. J Neurosurg 60:119512001984

    • Search Google Scholar
    • Export Citation
  • 38

    Wyler ARWalker GSomes G: The morbidity of long-term seizure monitoring using subdural strip electrodes. J Neurosurg 74:7347371991

    • Search Google Scholar
    • Export Citation
TrendMD
Metrics

Metrics

All Time Past Year Past 30 Days
Abstract Views 107 107 9
Full Text Views 83 57 2
PDF Downloads 130 99 2
EPUB Downloads 0 0 0
PubMed
Google Scholar