Transsylvian-Transinsular Approaches to the Insula and Basal Ganglia

 

 

 

 

Neurosurgery 70:824–834, 2012 DOI: 10.1227/NEU.0b013e318236760d 

Lesions in the insula and basal ganglia can be risky to resect because of their depth and proximity to critical structures, particularly in the dominant hemi- sphere. Transsylvian approaches shorten the surgical distance to these lesions, preserve perisylvian temporal and frontal cortex, and minimize brain transgression. OBJECTIVE: To report our experience with transsylvian-transinsular approaches to vascular lesions.

METHODS: The anterior approach opened the sphenoidal and insular portions of the sylvian fissure and exposed the limen insulae and short gyri, whereas the posterior approach opened the insular and opercular portions of the sylvian fissure and exposed the circular sulcus and long gyri.

RESULTS: Forty-one patients with vascular lesions (24 arteriovenous malformations [AVMs] and 17 cavernous malformations) were treated surgically with a transsylvian- transinsular approach. Complete resection was obtained in 87.5% of AVMs and 95% of cavernous malformations. Permanent neurological morbidity related to surgery was observed in 2 AVM patients (5%), with the remaining 39 patients (95%) improved or unchanged postoperatively (modified Rankin Scale scores 0-2 in 83%). There were no new language deficits in patients with dominant hemisphere lesions.

CONCLUSION: Transsylvian-transinsular approaches safely expose vascular pathology in or deep to the insula while preserving overlying eloquent cortex in the frontal and temporal lobes. The anterior transsylvian-transinsular approach can be differentiated from the posterior approach based on technical differences in splitting the sylvian fis- sure and anatomic differences in final exposure. Discriminating patient selection and careful microsurgical technique are essential.

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

Neurosurg Focus 27 (2):E7, 2009
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.

Methods
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.

Results
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).

Conclusions
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.