'Moderate global aphasia': A generalized decline of language processing caused by glioma surgery but not stroke.

Unlike stroke, neurosurgical removal of left-hemisphere gliomas acts upon a reorganized language network and involves brain areas rarely damaged by stroke. We addressed whether this causes the profiles of neurosurgery- and stroke-induced language impairments to be distinct. K-means clustering of language assessment data (neurosurgery cohort: N = 88, stroke cohort: N = 95) identified similar profiles in both cohorts. But critically, a cluster of individuals with specific phonological deficits was only evident in the stroke but not in the neurosurgery cohort. Thus, phonological deficits are less clearly distinguished from other language deficits after glioma surgery compared to stroke. Furthermore, the correlations between language production and comprehension scores at different linguistic levels were more extensive in the neurosurgery than in the stroke cohort. Our findings suggest that neurosurgery-induced language impairments do not correspond to those caused by stroke, but rather manifest as a 'moderate global aphasia' - a generalized decline of language processing abilities.

Functional linguistic specificity of the left frontal aslant tract for spontaneous speech fluency: Evidence from intraoperative language mapping.

The left frontal aslant tract (FAT) has been proposed to be relevant for language, and specifically for spontaneous speech fluency. However, there is missing causal evidence that stimulation of the FAT affects spontaneous speech, and not language production in general. We present a series of 12 neurosurgical cases with awake language mapping of the cortex near the left FAT. Tasks for language mapping included the commonly used action picture naming, and sentence completion, tapping more specifically into spontaneous speech. A task dissociation was found in 10 participants: while being stimulated on specific sites, they were able to name a picture but could not complete a sentence. Overlaying of these sites on preoperative white-matter tract reconstructions revealed that in each individual case they were located on cortical terminations of the FAT. This corroborates the language functional specificity of the left FAT as a tract underlying fluent spontaneous speech.

Comprehension and production of nouns and verbs in temporal lobe epilepsy.

Previous research on linguistic performance at the single-word level in patients with temporal lobe epilepsy (TLE) has mostly been limited to the comprehension and production of nouns, and findings have been inconsistent. Results are likewise limited and controversial regarding the lateralization of the epileptogenic focus. The present study investigates comprehension and production of nouns and verbs in patients with left and right TLE (12 in each group). We designed a comprehension (word-picture matching) test and a production (naming) test, matched on a range of psycholinguistic parameters for the two word classes. The results showed impaired verb comprehension in patients with left TLE and impaired noun and verb production in both groups of patients compared to the control group. Patients with left and right TLE differed significantly on verb comprehension and noun production, whereas verb production was equally impaired in the two groups of patients. These findings suggest difficulties with single-word processing in patients with both left and right TLE, which are more prominent for verbs than for nouns in patients with left TLE. The verb production (action naming) test turned out to be the most effective tool for assessing linguistic difficulties at the single-word level in patients with TLE.

A novel device for hands-free positioning and adjustment of the surgical microscope.

The authors have developed a novel device, which they have named Mari, that allows hands-free utilization of the surgical microscope. The device is attached to the eyepieces of a multifunction counterweight-balanced surgical microscope and consists of a metallic holder with supportive plates that facilitate interaction between the device and surgeon's head. On the holder are installed 1) an electric switch, which allows the surgeon to release the microscope's magnetic clutches, allowing movement of the microscope along the x, y, and z axes as well as the rotational and diagonal ones, and 2) a joystick at the level of the surgeon's mouth for adjustment of focus and zoom. The authors report on the initial experience with the use of the device at the Burdenko Neurosurgery Institute, where the senior author used it in approximately 600 procedures between 2006 and 2012. The surgeries ranged in difficulty and in duration (from 20 minutes to 7 hours, median 2.5 hours). Use of the Mari device resulted in increased accuracy of the surgical manipulations and a reduction in the duration of surgery.

Microsurgical third ventriculostomy with stenting in intrinsic brain tumors involving anterior third ventricle.

OBJECTIVE: Microsurgical fenestration of the third ventricular floor performed in one session with resection of deep seated tumors has been recently demonstrated as an approach to specifically address the concomitant obstructive hydrocephalus. As with endoscopic third ventriculostomy, occlusion of the stoma may result in progression of the obstructive hydrocephalus. In order to provide reliable communication between the basal cisterns and ventricles, we propose stenting of the stoma in cases of direct surgical approach to deep seated tumors. METHODS: After performing tumor resection through the anterior transcallosal approach, premamillar and Liliequist's membranes were identified and fenestrated. A silicon stent was inserted into the prepontine cistern through the fenestrated floor of the third ventricle; the stent connected the third and lateral ventricles with the basal cisterns. RESULTS: Microsurgical ventriculostomy of the third ventricle and stenting of the stoma was performed in 9 patients simultaneously with tumor resection (5 cases), open biopsy (3 cases), or microsurgical dissection of severe adhesions at the level of Monro foramina (1 case). In 7 cases, the third ventricular floor was infiltrated with the tumor and obstruction of the aqueduct persisted after tumor surgery; in 2 patients, high risk of reocclusion at the level of Monro foramen was expected. Stenting of the ventricular system provided patency of the stoma and Monro foramen. None of the patients required a shunt postoperatively. The follow-up time ranged from 3 to 22 months. CONCLUSION: Microsurgical fenestration of the third ventricle floor combined with stoma stenting can be a viable option for hydrocephalus control.

Intraoperative direct third ventriculostomy and aqueductal stenting in deep-seated midline brain tumor surgery.

OBJECTIVE: Surgical resection of deep-seated midline brain tumors does not always resolve obstruction of cerebrospinal fluid pathways, and an additional operation--ventricular shunting--is required. To prevent postoperative obstructive hydrocephalus, we combine tumor removal and internal ventricular shunting in 1 stage. METHODS: Between 2000 and 2006, 82 patients with deep-seated midline brain tumors (tumors of the third ventricle, pineal region, thalamus, upper brainstem, and superior half of the fourth ventricle) underwent 84 tumor resections with intraoperative internal ventricular shunting. Two types of intraoperative shunting were performed: direct third ventriculostomy with fenestration of the premammillary membrane of the third ventricle floor and Liliequist's membrane, 53 operations; and aqueductal stenting, 30 operations. In 1 patient, third ventriculostomy and aqueductal stenting were performed simultaneously. RESULTS: As most of the tumors had an infiltrative growth pattern, gross total tumor removal was achieved in only 31% of patients in this series. There were no fatal outcomes related to the surgery. Follow-up data were collected in 73 patients (89%) and ranged from 2 to 68 months (median, 16 months). Additional shunting because of inadequate function of stoma or stent was performed in 13 patients at various times after surgery (median, 30 days). The Kaplan-Meier survival analysis demonstrated that at 12 and 24 months the intraoperative direct third ventriculostomy success rates were 67 and 61%, respectively; aqueductal stenting success rates were 93% at both 12 and 24 months. CONCLUSION: Intraoperative direct third ventriculostomy and aqueductal stenting under direct visual control were found to be reliable methods of hydrocephalus management in patients with deep-seated midline brain tumors.