Innovative Surgical Technique Gives Hope To Patients Suffering From Refractory Epilepsy

"Recent observations by our team and others confirm the previously unsuspected role played by the insula in cases of refractory epilepsy. The non-recognition of insular seizures has probably been responsible for some failures in epilepsy surgery in the past," note doctors Alain Bouthillier, neurosurgeon, and Dang Khoa Nguyen, neurologist, the study's principal investigators, who teach at Université de Montréal and are researchers at the CHUM's research centre.

For many years, insular surgery to treat refractory epilepsy was abandoned and it is still rarely practiced because of the risk of damaging important structures of the brain. Initial attempts to resect the insula resulted in a high rate of complications, including hemiparesis (partial paralysis) and dysphasia (language loss). However, better understanding of the anatomy of the brain, in particular, the cerebral cortex and its vascular system, combined with the use of microsurgical techniques, now enable surgery to be performed on the insula, with greatly reduced risk to the patient. "This is the first cohort of patients with refractory epilepsy to have undergone such a procedure since the work of neurosurgeon Wilder Penfield in the 1950s," adds one of the investigators, Dr. Ramez Malak, neurosurgical resident.

Methodology

A retrospective study over the past ten years evaluated cases of patients with refractory epilepsy who had undergone insular surgery. In order to confirm the epileptic foci, intracranial electrodes were implanted, with the surgeon using neuronavigation and magnetic resonance imaging of the brain. Insulectomy was performed either

• as part of an insulooperculectomy, in which the insula and the opercula (meaning "lids": the lips of the deep fold that separates the frontal, temporal and parietal lobes) are completely removed;
• by resection of the temporal lobe with insulectomy;
• or as a pure insulectomy.

Results

Nine patients were treated successfully with insular surgery, seven for refractory epilepsy without tumour and two with refractory epilepsy associated with the presence of tumours. After surgery, some patients presented with transient complications (hemiparesis, dysphasia), which disappeared after a few days or weeks post-surgery.

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. She was also able to stop taking anticonvulsants.

The role of the insula

The insula is one of the lobes of the brain. Its role is still not well understood but its multiple connections with other parts of the brain reflect its involvement in a wide range of functions: automatic, sensory, motor, speech, auditory, olfactory, gustatory and limbic (emotion).

The CHUM epilepsy multidisciplinary team

The epilepsy multidisciplinary team is one of the principal groups of clinicians and professionals in Quebec treating people suffering from epilepsy. This unit is a centre of excellence, where services to its clientele and fundamental and clinical research and teaching activities are concentrated. Providing tertiary and quaternary services, the members of the CHUM epilepsy multidisciplinary team work in conjunction with partners in the health network to provide their patients with continuity of care.