Temporal Isthmus Research Articles

The Transtemporal Isthmus Approach for Insular Glioma Surgery.

Maximal and safe removal of insular gliomas by a transinsular cortex approach is challenging. In this article, a new transtemporal isthmus approach to resect insular gliomas is presented. We retrospectively examined 53 patients with insular glioma who underwent resection through the temporal isthmus approach using magnetic resonance imaging and functional neuronavigation guidance and intraoperative electrophysiological monitoring. Extent of resection was determined using intraoperative magnetic resonance imaging. Fifty-three patients were included for analysis, 30 men and 23 women. The median (range) age was 45 (26-70) years. Tumor laterality was left in 22 patients and right in 31. All tumors involved at least zone III or IV (Berger-Sanai classification system), including zones I-IV were involved in 29 (54.7%) and zones III and IV in 17 (32.0%). Among the 37 low-grade gliomas, preoperative median (IQR) volume was 45.7 (31.8, 60.3) cm 3 , and gross total resection was achieved in 24 (64.9%). Among the 16 high-grade gliomas, preoperative median (IQR) volume was 45.3 (40.1, 54.0) cm 3 , and gross total resection was achieved in 14 (87.5%). The median (IQR) extent of resection of the whole group was 100% (89%-100%). The median (IQR) postoperative Karnofsky performance score 3 months after surgery was 90 (80-90). Mean temporal isthmus width was significantly higher in the affected side (involving tumor) than the contralateral one (21.6 vs 11.3 mm; 95% CI: 9.3 to 11.3, P < .01). Muscle strength was grade 4 or higher, and speech was nearly normal in all patients 3 months after surgery. Insular glioma surgery using the transtemporal isthmus approach can achieve safe and maximum resection. A widened temporal isthmus provides a surgical pathway for transisthmic resection of insular tumor.

Transopercular Insular Approach, Overcoming the Training Curve Using a Cadaveric Simulation Model: 2-Dimensional Operative Video.

Transopercular approach to the insula is indicated for resection of insular low-grade gliomas, particularly for Yasargil's 3B, 5A, and 5B types. Nevertheless, the infrequent location and its challenging approach make it difficult to master the surgery. Consequently, a realistic laboratory training model might help to acquire key surgical skills. In this video, we describe a cadaveric-based model simulating the resection of a temporo-insular low-grade glioma. Kingler's fixation technique was used to fix the cadaver head before injecting red and blue colorants for a realistic vascular appearance. Hemisphere was frozen for white matter tract dissection. Tractography and intraoperative eloquent areas were extrapolated from a glioma patient by using a neuronavigation system. Then, a fronto-temporal craniotomy was performed through a question mark incision, exposing from inferior temporal gyrus up to middle frontal gyrus. After cortical anatomic landmark identification, eloquent areas were extrapolated creating a simulated functional cortical map. Then, transopercular noneloquent frontal and temporal corticectomies were performed, followed by subpial resection. Detailed identification of Sylvian vessels and insular cortex was demonstrated. Anatomic resection limits were exposed, and implicated white matter bundles, uncinate and fronto-occipital fascicles, were identified running through the temporal isthmus. Finally, a temporo-mesial resection was performed. In summary, this model provides a simple, cost-effective, and very realistic simulation of a transopercular approach to the insula, allowing the development of surgical skills needed to treat insular tumors in a safe environment. Besides, the integration of simulated navigation has proven useful in better understanding the complex white matter anatomy involved. Cadaver donation, subject or relatives, includes full consent for publication of the images. For the purpose of this video, no ethics committee approval was needed. Images correspond to a cadaver head donation. Cadaver donation, subject or relatives, includes full consent for any scientific purposes involving the corpse. The consent includes image or video recording. Regarding the intraoperative surgical video and tractography, the patient gave written consent for scientific divulgation prior to surgery.

Lesion site patterns in severe, nonverbal aphasia to predict outcome with a computer-assisted treatment program.

To test whether lesion site patterns in patients with chronic, severe aphasia who have no meaningful spontaneous speech are predictive of outcome following treatment with a nonverbal, icon-based computer-assisted visual communication (C-ViC) program. Retrospective study in which computed tomographic scans performed 3 months after onset of stroke and aphasia test scores obtained before C-ViC therapy were reviewed for patients after receiving C-ViC treatment. A neurology department and speech pathology service of a Department of Veterans Affairs medical center and a university aphasia research center. Seventeen patients with stroke and severe aphasia who began treatment with C-ViC from 3 months to 10 years after onset of stroke. Level of ability to use C-ViC on a personal computer to communicate. All patients with bilateral lesions failed to learn C-ViC. For patients with unilateral left hemisphere lesion sites, statistical analyses accurately discriminated between those who could initiate communication with C-ViC from those who were only able to answer directed questions. The critical lesion areas involved temporal lobe structures (Wernicke cortical area and the subcortical temporal isthmus), supraventricular frontal lobe structures (supplementary motor area or cingulate gyrus 24), and the subcortical medial subcallosal fasciculus, deep to the Broca area. Specific lesion sites were also identified for appropriate candidacy for C-ViC. Lesion site patterns on computed tomographic scans are helpful to define candidacy for C-ViC training, and to predict outcome level. A practical method is presented for clinical application of these lesion site results in combination with aphasia test scores.

Cerebral blood flow in subcortical global aphasia. Perisylvian cortical hypoperfusion as a crucial role.

Global aphasia after subcortical stroke is very rare, and its pathophysiology remains unsolved. To clarify the mechanism underlying subcortical global aphasia, we investigated lesion sites and cerebral blood flow in patients with subcortical global aphasia and nonaphasic patients with subcortical stroke. We examined four patients with global aphasia and four nonaphasic patients. Language testing was performed more than 4 weeks after the onset. Measurement of cerebral blood flow was done between 35 and 75 days after stroke by using single-photon emission computed tomography (SPECT) with N-isopropyl-p[123I]iodoamphetamine as a tracer and three-dimensional surface display generated from SPECT. All aphasic patients had subcortical lesions in the putamen, posterior internal capsule, temporal isthmus, and periventricular white matter in the left hemisphere. No cortical lesions were found on either magnetic resonance imaging or computed tomographic scanning. The nonaphasic patients had smaller periventricular white matter lesions and no temporal isthmus lesions. All aphasic patients showed cortical hypoperfusion mainly in the perisylvian areas, including Broca's and Wernicke's areas. In contrast, cortical cerebral blood flow of the nonaphasic patients was decreased in smaller areas and spared the perisylvian language areas. These results suggest that cortical hypoperfusion in the perisylvian language areas, presumably due to undercutting of the white matter, is crucial for the development of subcortical global aphasia.

Late Recovery of Auditory Comprehension in Global Aphasia

This study examined the relationship between recovery of auditory comprehension in global aphasia patients after 1 year post onset, and temporal lobe lesion in Wernicke's cortical area vs temporal lobe lesion in the subcortical temporal isthmus area. Computed tomographic scans and language behavior were examined in 14 right-handed globally aphasic stroke patients with lesion in the left hemisphere. Nine patients had large cortical/subcortical frontal, parietal, and temporal lobe lesion that included more than half of Wernicke's cortical area (FPT cases). Five patients had large cortical/subcortical frontal and parietal lobe lesion, but only subcortical temporal lobe lesion, including the temporal isthmus (FPTi cases). All patients were tested acutely at 1 to 4 months post onset and again at 1 to 2 years post onset. There was a significantly greater increase in the amount of recovery that had taken place after 1 to 2 years post onset for the FPTi group vs the FPT group in the overall Boston Diagnostic Aphasia Examination (BDAE) Auditory Comprehension Z score. In four of the five FPTi cases, the late BDAE Auditory Comprehension Z scores were above -0.5 (mild-to-moderate comprehension deficits). Most recovery was in single-word comprehension. In eight of the nine FPT cases, the late BDAE Auditory Comprehension Z-scores were below -0.5 (moderate-to-severe comprehension deficits). There was no significant difference between the two groups in recovery of spontaneous speech, repetition, or naming, where severe deficits remained in most cases.(ABSTRACT TRUNCATED AT 250 WORDS)

Distributed anatomy of transcortical sensory aphasia.

We examined four patients with transcortical sensory aphasia and eight with milder language disturbances but with similar thalamic and/or temporo-occipital lesions. Specific attention was paid to differentiation of the computed tomographic lesion site of the milder cases from the transcortical sensory aphasia cases. The critical lesion for transcortical sensory aphasia in these patients involved pathways in the posterior periventricular white matter adjacent to the posterior temporal isthmus, pathways that are probably converging on the inferolateral temporo-occipital cortex. Analysis of the language function of these patients, of the influence of sensory modalities on language function, and of the interaction between semantic memory and semantic lexical functions suggests the existence of a specific brain system for semantic functions. This semantic system has a particular distributed anatomy. We propose that damage to this system may have a variety of clinical manifestations in language and in memory, depending on the exact lesion configuration.

CT Scan Lesion Localization and Response to Melodic Intonation Therapy with Nonfluent Aphasia Cases

The purpose of this retrospective study was to investigate the relationship between CT scan lesion localization and good or poor response to Melodic Intonation Therapy (MIT) as measured by pre- and post-MIT treatment scores. The four good response (GR) cases improved in speech characteristics ratings for Phrase Length and Grammatical Form on the Boston Diagnostic Aphasia Examination; the four poor response (PR) cases showed no improvement. The GR cases had lesions which involved Broca's area and/or white matter deep to it plus large superior lesion extension into periventricular white matter deep to the lower motor cortex area for face. These GR cases had no large lesion in Wernicke's area and no lesion in the temporal isthmus or the right hemisphere. The PR cases, however, had bi-lateral lesions or lesion including Wernicke's area or the temporal isthmus.

Vascular lesions affecting the visual pathways.

There is no better means of acquiring an understanding of the subject of neuro-ophthalmology than by firsthand examination of pathologic specimens. For the ophthalmologist it is a most enlightening experience to see the great frequency with which sections of the brain contain lesions that affect, in a variety of interesting ways, the visual pathways. The autopsy material on which this discussion is based was selected by me from a large number of brain sections inspected at the neuropathology conferences conducted by Dr. J. M. Nielsen, of Los Angeles. The present discussion will deal primarily with involvement of the visual pathways through lesions in the temporal isthmus and in the occipital lobes. When the ophthalmologist is confronted with a cerebral defect producing a homonymous hemianopia without optic atrophy or impairment of the pupillary light reflex, he knows that the lesion is situated somewhere posterior to the lateral geniculate bodies. But for