Functional outcome after language mapping for insular World Health Organization Grade II gliomas in the dominant hemisphere: experience with 24 patients

Abstract

<jats:sec> <jats:title>Object</jats:title> <jats:p>Despite the report of recent experiences of insular surgery in the past decade, there has been no series specifically dedicated to studying functional outcome following resection of insular WHO Grade II gliomas involving the dominant hemisphere, in patients with no or only mild preoperative language deficit. In this article, the authors analyze the contribution of awake mapping for preservation of brain function, especially language, in a homogeneous series of 24 patients who underwent surgery for insular Grade II gliomas within the dominant insular lobe.</jats:p></jats:sec> <jats:sec> <jats:title>Methods</jats:title> <jats:p>Twenty-four patients underwent surgery for an insular Grade II glioma involving the dominant hemisphere (22 left, 2 right), revealed by seizures in all but 1 case. The preoperative neurological examination result was normal in 17 patients (71%), whereas 7 patients presented with language disorders detected using an accurate language assessment performed by a speech therapist. All surgeries were performed on awake patients utilizing intra-operative language mapping involving cortical and subcortical stimulation.</jats:p></jats:sec> <jats:sec> <jats:title>Results</jats:title> <jats:p>There were no intrasurgical complications or postsurgical sensorimotor deficits. Despite an immediate postoperative language worsening in 12 cases (50%), all patients recovered to a normal status within 3 months, and 6 cases even improved in comparison with their preoperative examination results. The 24 patients returned to normal social and professional lives. Moreover, the surgery had a favorable impact on epilepsy in all but 4 cases (83%). On control MR imaging, 62.5% of resections were total or subtotal. Three patients underwent a second or third awake surgery, with no additional deficit. All but 2 patients (92%) are alive after a mean follow-up of 3 years (range 3–133 months).</jats:p></jats:sec> <jats:sec> <jats:title>Conclusions</jats:title> <jats:p>Although insular surgery was long believed to be too risky, the present results show that the rate of permanent deficit, especially dysphasia, following resection of Grade II gliomas involving the dominant insula has been dramatically reduced (none in this patient series), thanks to the systematic use of intraoperative awake mapping, even in cases of repeated operations. Furthermore, patient quality of life may be improved due to a decrease of epilepsy after surgery. Thus, the authors suggest systematically considering resection when an insular Grade II glioma is diagnosed after seizures in a patient with no or mild deficit, even a glioma invading the dominant hemisphere.</jats:p></jats:sec>

Surgical assessment of the insula. Part 2: validation of the Berger-Sanai zone classification system for predicting extent of glioma resection

“…6,11,13 Furthermore, surgery can be accomplished with a median EOR of 80%-82% and minimal morbidity of long-term language (0.8%) and motor function (1.6%). 2,3,8,13,14 The significance of volumetric EOR on overall survival for patients with both low-and high-grade insular gliomas has been demonstrated in multiple previously published reports.…”

“…Prior published reports suggest that aggressive resection of both low-and high-grade insular gliomas may be accomplished with an acceptable morbidity profile. 2,3,[7][8][9][10]13,14,17 Maximal extent of resection (EOR) predicts superior overall and progression-free survival as well as improved seizure control. 6,11,13 The majority of insular gliomas not only involve the insular lobe but can also infiltrate into portions of the frontal operculum and temporal lobe.…”

Technical nuances for surgery of insular gliomas: lessons learned

“…The publication of Yaşargil's experience 53 with these tumors prompted neurosurgeons to revisit the surgical option. Since the publication of that work in 1992, 53 several studies have shown a positive impact of tumor resection on PFS and OS with acceptable surgical morbidity rates for both low-grade (WHO Grade I and II) 2,9,10,15,17,19,39,46,55 and high-grade (WHO Grade III and IV) tumors. 27,34,37,46,55 Despite the lack of Class I evidence, data from several recent studies suggest that EOR is one of the main prognostic factors in OS, PFS, and ma-lignant transformation.…”

A case of secondary somatosensory epilepsy with a left deep parietal opercular lesion: successful tumor resection using a transsubcentral gyral approach during awake surgery

“…Some reports describing surgery of the insula may be of use as references. 6,7,17,28,37 The transsylvian approach with wide opening of the fissure for observation of this location may be effective; however, the risk of vascular injury and pial destruction is not insignificant. Furthermore, the transsylvian approach is associated with high neurological morbidity in surgery for medial temporal tumors.…”