Clinical Study

Parasagittal Transinsular Electrodes for Stereo-EEG in Temporal and Insular Lobe Epilepsies
Santiago Gil Robles^a, Philippe Gelisse^a, Hassan El Fertit^a, Cornel Tancu^b, Hugues Duffau^a, Arielle Crespel^a, Philippe Coubes<sup>a, b

a</sup>Epilepsy Unit, Departments of Neurosurgery and Neurology, and
^bResearch Unit in Movement Disorders (URMA), IGF-UMR CNRS 5203, INSERM U661, Montpellier, France

Address of Corresponding Author

Stereotact Funct Neurosurg 2009;87:368-378 (DOI: 10.1159/000249818)

  Key Words

• Stereoelectroencephalography
• Epilepsy
• Surgery
• Insula
• Temporal lobe

  Abstract

Objective: Direct invasive EEG recordings of the insula - due to its particular anatomical position, deeply seated between both opercula - can only be performed with intracerebral electrodes. To date, the technique most commonly used for insular stereoelectroencephalography (SEEG) is the orthogonal-transopercular electrode approach with the Talairach methodology. We propose another technique utilizing MRI with transinsular parasagittal electrodes and a posterior entry point. This avoids passing through the opercula and sylvian vessels running over the insular surface. Methods: Nine patients, whose seizures implicated the insula, underwent brain surgery. Under general anesthesia with a Leksell frame, 3D-T₁ SPGR MRI with gadolinium enhancement was achieved. Surgical planning was performed using the StealthStation with an entry point in the parieto-occipital junction setting the target for the first contact of the lead at the most anterior part of the insula. The trajectory was manipulated in order to have at least 4 contacts per electrode track within the insular cortex. All patients had a postoperative MRI to verify the exact position of each contact. Results: Insular seizures were recorded in all patients. There was neither intracranial bleeding nor infection. In all of the cases, except 1, the seizures recorded were found to be propagations of the primary epileptic zone located in the temporal lobe, either in the mesial structures or the superior temporal gyrus. Eight patients were operated, 7 with an antero-mesial temporal lobectomy and 1 with dysplasia of the superior temporal gyrus. No insular resections were performed. Conclusion: We report a novel technique for insular SEEG with parasagittal electrodes, parallel to the insular cortex, with an entry point at the parieto-occipital junction. This technique is based entirely on use of MRI, and avoids passing through the opercula and sylvian vessels.

Copyright © 2009 S. Karger AG, Basel

  Author Contacts

Philippe Coubes
Service de Neurochirurgie, Hôpital Gui de Chauliac
80 avenue Fliche
FR-34295 Montpellier Cedex 05 (France)
Tel. +33 467 337 261, Fax +33 467 337 464, E-Mail p-coubes@chu-montpellier.fr

  Article Information

Received: September 16, 2008
Accepted after revision: March 17, 2009
Published online: October 21, 2009
Number of Print Pages : 11
Number of Figures : 5, Number of Tables : 1, Number of References : 26