Microsurgery Offers Hope to Patients Suffering From Refractory Epilepsy

An innovative surgical technique now enables surgeons to perform insular surgery to treat refractory epilepsy, a procedure previously abandoned due to of the risk of damaging important structures of the brain.

Researchers at the Centre Hospitalier de l'Université de Montréal (CHUM, Canada) conducted a retrospective study of patients who underwent surgery for insular lesions associated with epilepsy over a period of 10 years. In order to confirm the epileptic foci, intracranial electrodes were implanted, with the surgeon using neuronavigation and magnetic resonance imaging (MRI) of the brain. The researchers found that nine patients were treated successfully with insular surgery, seven for refractory epilepsy without tumor and two with refractory epilepsy associated with the presence of tumors. After an average follow-up of 54 months, a seizure-free outcome had been achieved in six of seven cases in the epilepsy surgery group. Postoperatively, the majority of patients suffered from minor reversible hemipareses that disappeared completely within a few months. There was no surgical mortality. One patient, who had suffered from regular epileptic seizures, despite numerous essays with a variety of anticonvulsants, has had no seizures since surgery and no complications, and was able to stop taking anticonvulsants. The study was published in the June 2009 issue of the Journal of Neurosurgery.

"Recent observations by our team and others confirm the previously unsuspected role played by the insula in cases of refractory epilepsy. The nonrecognition of insular seizures has probably been responsible for some failures in epilepsy surgery in the past,” said principal investigators neurosurgeon Alain Bouthillier, M.D., and neurologist Dang Khoa Nguyen, M.D.

The insular cortex (often called insula) is a cerebral cortex structure deep within the lateral sulcus, between the temporal and the parietal lobes. The insula has multiple connections with other parts of the brain, which reflect its involvement in a wide range of sensory, motor, speech, auditory, olfactory, gustatory, and limbic functions. For many years, insular surgery to treat refractory epilepsy was abandoned, and it is still rarely practiced because of the risks involved. Initial attempts to resect the insula resulted in a high rate of complications, including hemiparesis (partial paralysis) and dysphasia (language loss). However, a better understanding of the anatomy of the brain--in particular the cerebral cortex and its vascular system--and new microsurgical techniques now enable surgery to be performed on the insula with a greatly reduced risk to the patient.

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