Operculoinsular cortectomy for refractory epilepsy. Part 1: Is it effective?

Abstract

<jats:sec><jats:title>OBJECTIVE</jats:title><jats:p>Patients with refractory epilepsy of operculoinsular origin are often denied potentially effective surgical treatment with operculoinsular cortectomy (also termed operculoinsulectomy) because of feared complications and the paucity of surgical series with a significant number of cases documenting seizure control outcome. The goal of this study was to document seizure control outcome after operculoinsular cortectomy in a group of patients investigated and treated by an epilepsy team with 20 years of experience with this specific technique.</jats:p></jats:sec><jats:sec><jats:title>METHODS</jats:title><jats:p>Clinical, imaging, surgical, and seizure control outcome data of all patients who underwent surgery for refractory epilepsy requiring an operculoinsular cortectomy were retrospectively reviewed. Tumors and progressive encephalitis cases were excluded. Descriptive and uni- and multivariate analyses were done to determine seizure control outcome and predictors.</jats:p></jats:sec><jats:sec><jats:title>RESULTS</jats:title><jats:p>Forty-three patients with 44 operculoinsular cortectomies were studied. Kaplan-Meier estimates of complete seizure freedom (first seizure recurrence excluding auras) for years 0.5, 1, 2, and 5 were 70.2%, 70.2%, 65.0%, and 65.0%, respectively. With patients with more than 1 year of follow-up, seizure control outcome Engel class I was achieved in 76.9% (mean follow-up duration 5.8 years; range 1.25–20 years). With multivariate analysis, unfavorable seizure outcome predictors were frontal lobe–like seizure semiology, shorter duration of epilepsy, and the use of intracranial electrodes for invasive monitoring. Suspected causes of recurrent seizures were sparing of the language cortex part of the focus, subtotal resection of cortical dysplasia/polymicrogyria, bilateral epilepsy, and residual epileptic cortex with normal preoperative MRI studies (insula, frontal lobe, posterior parieto-temporal, orbitofrontal).</jats:p></jats:sec><jats:sec><jats:title>CONCLUSIONS</jats:title><jats:p>The surgical treatment of operculoinsular refractory epilepsy is as effective as epilepsy surgeries in other brain areas. These patients should be referred to centers with appropriate experience. A frontal lobe–like seizure semiology should command more sampling with invasive monitoring. Recordings with intracranial electrodes are not always required if the noninvasive investigation is conclusive. The complete resection of the epileptic zone is crucial to achieve good seizure control outcome.</jats:p></jats:sec>

Predictors of outcomes after surgery for medically intractable insular epilepsy: A systematic review and individual participant data meta‐analysis

“…Despite historical high morbidity rates associated with surgery for IE, 39 modern reports demonstrate that IE surgery can be carried out with moderate permanent morbidity. 16,27 Overall, 42% of patients undergoing surgery for IE experienced neurological deficits in our study, but only a reasonably small fraction of these complications were permanent (7.8% of all surgically treated patients). Additionally, the vast majority of patients who exhibited transient deficits recovered rapidly (68.9% within 3 months).…”

“…These studies have shown IE surgery to be feasible, albeit with variable seizure freedom rates and a non‐negligible neurological morbidity profile. Consequently, widespread adoption of IE surgery has been hampered, primarily due to concerns of its efficacy 16 and safety 34 profile and perceived “unfavorable risk‐to‐benefit ratio” 34–36 …”

“… 2 , 3 , 4 Increased safety of both open 5 , 6 , 7 , 8 and stereotactic electroencephalography (SEEG) electrode placement in the insula and peri‐Sylvian region 2 , 7 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 has led to increased detection of IE in many centers around the world. 2 , 6 , 11 , 16 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 Over the last 15 years, several institutions have reported their experience with resective surgery for IE. 6 , 16 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 29 , 30 , 31 , 32 , 33 These studies have shown IE surgery to be feasible, albeit with variable seizure freedom rates and a non‐negligible neurological morbidi...…”

Laser interstitial thermal therapy for the treatment of insular lesions: A systematic review

“…Around one third of the patients experienced a temporary paresis. Gireesh et al, reported one intracerebral hematoma following LITT that required a decompressive hemicraniectomy, but subsequently had a good outcome ( 26 , 34 ). Bouthillier et al, recently published the results of 44 insulo-opercular cortectomies in 43 patients achieving a an Engel class 1 outcome in 77% (mean follow-up 6 years) with a 7% permanent postoperative deficit.…”

Structural Connectivity Alterations in Operculo-Insular Epilepsy

“…Furthermore, an icEEG recording was performed in eight OIE and one TLE participants. In order to specifically study OIE, we only selected patients who had a favorable outcome following a partial or radical insular resection with or without an operculectomy [34,35] (Engel class I for seven patients and II for two patients; mean follow-up time 4.2 ± 1.3 years). Similarly, to ensure confident focus localization, all patients in the TLE group had to have unilateral hippocampal sclerosis and good outcome after anterior temporal lobectomy (Engel class I at last follow-up; mean follow-up time 3.1 ± 1.6 years).…”