Safety of an operculoinsulectomy in the language-dominant hemisphere for refractory epilepsy

Operculoinsular cortectomy is increasingly recognized as a therapeutic avenue for perisylvian refractory epilepsy. However, most neurosurgeons are reluctant to perform this type of procedure because of feared neurological complications, especially in the language-dominant hemisphere, as the insula is involved in speech and language processes. The goal of this retrospective study is to quantify the incidence and types of speech and language deficits associated with operculoinsulectomies in the dominant hemisphere for language, and to identify factors associated with these complications.

Clinical, imaging, and surgical data of all patients who had an operculoinsulectomy for refractory epilepsy at our center between 1998 and 2018 were reviewed. Language lateralization was determined by functional magnetic resonance imaging (fMRI) and/or Wada test. Speech and language assessments were carried out by neurosurgeons, neurologists, neuropsychologists and/or speech language pathologists, before surgery, during the first week after surgery, and at least 6 months after surgery.

Amongst 44 operculoinsulectomies, 13 were performed in the language-dominant hemisphere. 46% of these patients presented with transient aphasia post-surgery. However, a few months later, the patients' performances on language assessments were not statistically different from before surgery, thus suggesting a complete recovery of speech and language functions.

Temporary aphasias after operculoinsulectomy for refractory epilepsy in the language-dominant hemisphere are frequent, but eventually subside. Potential mechanisms underlying this recovery are discussed.