White matter fiber dissection of the optic radiations of the temporal lobe and implications for surgical approaches to the temporal horn

2004 ◽  
Vol 101 (5) ◽  
pp. 739-746 ◽  
Author(s):  
Eric H. Sincoff ◽  
Yunxi Tan ◽  
Saleem I. Abdulrauf

Object. The aim of this anatomical study was to define more fully the three-dimensional (3D) relationships between the optic radiations and the temporal horn and superficial anatomy of the temporal lobe by using the Klingler white matter fiber dissection technique. These findings were correlated with established surgical trajectories to the temporal horn. Such surgical trajectories have implications for amygdalohippocampectomy and other procedures that involve entering the temporal horn for the resection of tumors or vascular lesions. Methods. Ten human cadaveric hemispheres were prepared with several cycles of freezing and thawing by using a modification of the method described by Klingler. Wooden spatulas were used to strip away the deeper layers of white matter progressively in a lateromedial direction, and various association, projection, and commissural fibers were demonstrated. As the dissection progressed, photographs of each progressive layer were obtained. Special attention was given to the optic radiation and to the sagittal stratum of which the optic radiation is a part. The trajectories of fibers in the optic radiation were specifically studied in relation to the lateral, medial, superior, and inferior walls of the temporal horn as well as to the superficial anatomy of the temporal lobe. In three of the hemispheres coronal sections were made so that the relationship between the optic radiation and the temporal horn could be studied more fully. In all 10 hemispheres that were dissected the following observations were made. 1) The optic radiation covered the entire lateral aspect of the temporal horn as it extends to the occipital horn. 2) The anterior tip of the temporal horn was covered by the anterior optic radiation along its lateral half. 3) The entire medial wall of the temporal horn was free from optic radiation fibers, except at the level at which these fibers arise from the lateral geniculate body to ascend over the roof of the temporal horn. 4) The superior wall of the temporal horn was covered by optic radiation fibers. 5) The entire inferior wall of the temporal horn was free from optic radiation fibers anterior to the level of the lateral geniculate body. Conclusions. Fiber dissections of the temporal lobe and horn demonstrated the complex 3D relationships between the optic radiations and the temporal horn and superficial anatomy of the temporal lobe. Based on the results of this study, the authors define two anatomical surgical trajectories to the temporal horn that would avoid the optic radiations. The first of these involves a transsylvian anterior medial approach and the second a pure inferior trajectory through a fusiform gyrus. Lateral approaches to the temporal horn through the superior and middle gyri, based on the authors' findings, would traverse the optic radiations.

2012 ◽  
Vol 71 (suppl_1) ◽  
pp. ons160-ons172 ◽  
Author(s):  
Richard Gonzalo Párraga ◽  
Guilherme Carvalhal Ribas ◽  
Leonardo Christiaan Welling ◽  
Raphael Vicente Alves ◽  
Evandro de Oliveira

Abstract BACKGROUND: The fiber dissection technique provides unique 3-dimensional anatomic knowledge of the white matter. OBJECTIVE: To examine the optic radiation anatomy and its important relationship with the temporal stem and to discuss its findings in relation to the approaches to temporal lobe lesions. METHODS: We studied 40 cerebral hemispheres of 20 brains that had been fixed in formalin solution for 40 days. After removal of the arachnoid membrane, the hemispheres were frozen, and the Klingler technique was used for dissection under magnification. Stereoscopic 3-dimensional images of the dissection were obtained for illustration. RESULTS: The optic radiations are located deep within the superior and middle temporal gyri, always above the inferior temporal sulcus. The mean distance between the cortical surface and the lateral edge of the optic radiation was 21 mm. Its fibers are divided into 3 bundles after their origin. The mean distance between the anterior tip of the temporal horn and the Meyer loop was 4.5 mm, between the temporal pole and the anterior border of the Meyer loop was 28.4 mm, and between the limen insulae and the Meyer loop was 10.7 mm. The mean distance between the lateral geniculate body and the lateral margin of the central bundle of the optic radiation was 17.4 mm. CONCLUSION: The white matter fiber dissection reveals the tridimensional intrinsic architecture of the brain, and its knowledge regarding the temporal lobe is particularly important for the neurosurgeon, mostly because of the complexity of the optic radiation and related fibers.


1978 ◽  
Vol 48 (4) ◽  
pp. 622-627 ◽  
Author(s):  
Richard L. Sogg ◽  
Sarah S. Donaldson ◽  
Craig H. Yorke

✓ A 9-year-old schoolgirl received 6007 rads to the suprasellar region for craniopharyngioma. Five years later, a malignant astrocytoma developed in the right temporal lobe. We cite clinical and experimental evidence to support our suspicion that the glioma may have been induced by radiation.


2000 ◽  
Vol 93 (3) ◽  
pp. 498-505 ◽  
Author(s):  
Cole A. Giller ◽  
Maureen Johns ◽  
Hanli Liu

✓ Localization of targets during stereotactic surgery is frequently accomplished by identification of the boundaries between the gray matter of various nuclei and the surrounding white matter. The authors describe an intracranial probe developed for this purpose, which uses near-infrared (NIR) light.The probe fits through standard stereotactic holders and emits light at its tip. The scattered light is detected and analyzed by a spectrometer, with the slope of the trailing portion of the reflectance curve used as the measurement value.Near-infrared readings were obtained during 27 neurosurgical procedures. The first three operations were temporal lobectomies, with values obtained from tracks in the resected specimen and resection bed. In the next five procedures, the probe was inserted stereotactically to a depth of 1 to 2 cm with measurements obtained every 1 mm. The probe was then used in 19 stereotactic procedures for movement disorders, obtaining measurements every 0.5 to 1 mm to target depths of 6 to 8 cm to interrogate subcortical structures. The NIR signals were correlated to distances beneath the cortical surface measured on postoperative computerized tomography or magnetic resonance imaging by using angle correction and three-dimensional reconstruction techniques.The NIR values for white and gray matter obtained during the lobectomies were significantly different (white matter 2.5 ± 0.37, gray matter 0.82 ± 0.23 mean ± standard deviation). The NIR values from the superficial stereotactic tracks showed initial low values corresponding to cortical gray matter and high values corresponding to subcortical white matter.There was good correlation between the NIR signals and postoperative imaging in the 19 stereotactic cases. Dips due to adjacent sulci, a plateau of high signal due to subcortical white matter, a dip in the NIR signal during passage through the ventricle, dips due to the caudate nucleus, and peaks due to the white matter capsule between ventricle and thalamus were constant features. The putamen—capsule boundary and the lamina externa and interna of the globus pallidus could be distinguished in three cases. Elevated signals corresponding to the thalamic floor were seen in 10 cases. Nuances such as prior lesions and nonspecific white matter changes were also detected. There was no incidence of morbidity associated with use of the probe. Data acquisition was straightforward and the equipment required for the studies was inexpensive.The NIR probe described in this article seems to be able to detect gray—white matter boundaries around and within subcortical structures commonly encountered in stereotactic functional neurosurgery. This simple, inexpensive method deserves further study to establish its efficacy for stereotactic localization.


1998 ◽  
Vol 88 (6) ◽  
pp. 1058-1065 ◽  
Author(s):  
Kenneth R. Wagner ◽  
Guohua Xi ◽  
Ya Hua ◽  
Marla Kleinholz ◽  
Gabrielle M. de Courten-Myers ◽  
...  

Object. The authors previously demonstrated, in a large-animal intracerebral hemorrhage (ICH) model, that markedly edematous (“translucent”) white matter regions (> 10% increases in water contents) containing high levels of clotderived plasma proteins rapidly develop adjacent to hematomas. The goal of the present study was to determine the concentrations of high-energy phosphate, carbohydrate substrate, and lactate in these and other perihematomal white and gray matter regions during the early hours following experimental ICH. Methods. The authors infused autologous blood (1.7 ml) into frontal lobe white matter in a physiologically controlled model in pigs (weighing approximately 7 kg each) and froze their brains in situ at 1, 3, 5, or 8 hours postinfusion. Adenosine triphosphate (ATP), phosphocreatine (PCr), glycogen, glucose, lactate, and water contents were then measured in white and gray matter located ipsi- and contralateral to the hematomas, and metabolite concentrations in edematous brain regions were corrected for dilution. In markedly edematous white matter, glycogen and glucose concentrations increased two- to fivefold compared with control during 8 hours postinfusion. Similarly, PCr levels increased several-fold by 5 hours, whereas, except for a moderate decrease at 1 hour, ATP remained unchanged. Lactate was markedly increased (approximately 20 µmol/g) at all times. In gyral gray matter overlying the hematoma, water contents and glycogen levels were significantly increased at 5 and 8 hours, whereas lactate levels were increased two- to fourfold at all times. Conclusions. These results, which demonstrate normal to increased high-energy phosphate and carbohydrate substrate concentrations in edematous perihematomal regions during the early hours following ICH, are qualitatively similar to findings in other brain injury models in which a reduction in metabolic rate develops. Because an energy deficit is not present, lactate accumulation in edematous white matter is not caused by stimulated anaerobic glycolysis. Instead, because glutamate concentrations in the blood entering the brain's extracellular space during ICH are several-fold higher than normal levels, the authors speculate, on the basis of work reported by Pellerin and Magistretti, that glutamate uptake by astrocytes leads to enhanced aerobic glycolysis and lactate is generated at a rate that exceeds utilization.


2008 ◽  
Vol 108 (4) ◽  
pp. 775-781 ◽  
Author(s):  
Feng Wang ◽  
Tao Sun ◽  
Xing-Gang Li ◽  
Na-Jia Liu

Object The aim of this study was to use diffusion tensor tractography (DTT) to define the 3D relationships of the uncinate fasciculus, anterior commissure, inferior occipitofrontal fasciculus, inferior thalamic peduncle, and optic radiation and to determine the positioning landmarks of these white matter tracts. Methods The anatomy was studied in 10 adult human brain specimens. Brain DTT was performed in 10 healthy volunteers. Diffusion tensor tractography images of the white matter tracts in the temporal stem were obtained using the simple single region of interest (ROI) and multi-ROIs based on the anatomical knowledge. Results The posteroinferior insular point is the anterior extremity of intersection of the Heschl gyrus and the inferior limiting sulcus. On the inferior limiting sulcus, this point is the posterior limit of the optic radiation, and the temporal stem begins at the limen insulae and ends at the posteroinferior insular point. The distance from the limen insulae to the tip of the temporal horn is just one third the length of the temporal stem. The uncinate fasciculus comprises the core of the anterior temporal stem, behind which the anterior commissure and the inferior thalamic peduncle are located, and they occupy the anterior third of the temporal stem. The inferior occipitofrontal fasciculus passes through the entire temporal stem. The most anterior extent of the Meyer loop is located between the anterior tip of the temporal horn and the limen insulae. Most of the optic radiation crosses the postmedian two thirds of the temporal stem. Conclusions On the inferior limiting sulcus, the posteroinferior insular point is a reliable landmark of the posterior limit of the optic radiations. The limen insulae, anterior tip of the temporal horn, and posteroinferior insular point may be used to localize the white matter fibers of the temporal stem in analyzing magnetic resonance imaging or during surgery.


1970 ◽  
Vol 33 (3) ◽  
pp. 233-252 ◽  
Author(s):  
Murray A. Falconer

✓ The problem of childhood temporal lobe epilepsy is reviewed and illustrated from three cases in which the patients were freed from fits by temporal lobectomy. The pathological lesion (mesial temporal sclerosis) is discussed and the likelihood that many adult cases have gone unrecognized in childhood is emphasized.


1998 ◽  
Vol 89 (6) ◽  
pp. 962-970 ◽  
Author(s):  
Theodore H. Schwartz ◽  
Orrin Devinsky ◽  
Werner Doyle ◽  
Kenneth Perrine

Object. Although it is known that 5 to 10% of patients have language areas anterior to the rolandic cortex, many surgeons still perform standard anterior temporal lobectomies for epilepsy of mesial onset and report minimal long-term dysphasia. The authors examined the importance of language mapping before anterior temporal lobectomy. Methods. The authors mapped naming, reading, and speech arrest in a series of 67 patients via stimulation of long-term implanted subdural grids before resective epilepsy surgery and correlated the presence of language areas in the anterior temporal lobe with preoperative demographic and neuropsychometric data. Naming (p < 0.03) and reading (p < 0.05) errors were more common than speech arrest in patients undergoing surgery in the anterior temporal lobe. In the approximate region of a standard anterior temporal lobectomy, including 2.5 cm of the superior temporal gyrus and 4.5 cm of both the middle and inferior temporal gyrus, the authors identified language areas in 14.5% of patients tested. Between 1.5 and 3.5 cm from the temporal tip, patients who had seizure onset before 6 years of age had more naming (p < 0.02) and reading (p < 0.01) areas than those in whom seizure onset occurred after age 6 years. Patients with a verbal intelligence quotient (IQ) lower than 90 had more naming (p < 0.05) and reading (p < 0.02) areas than those with an IQ higher than 90. Finally, patients who were either left handed or right hemisphere memory dominant had more naming (p < 0.05) and reading (p < 0.02) areas than right-handed patients with bilateral or left hemisphere memory lateralization. Postoperative neuropsychometric testing showed a trend toward a greater decline in naming ability in patients who were least likely to have anterior language areas, that is, those with higher verbal IQ and later seizure onset. Conclusions. Preoperative identification of markers of left hemisphere damage, such as early seizure onset, poor verbal IQ, left handedness, and right hemisphere memory dominance should alert neurosurgeons to the possibility of encountering essential language areas in the anterior temporal lobe (1.5–3.5 cm from the temporal tip). Naming and reading tasks are required to identify these areas. Whether removal of these areas necessarily induces long-term impairment in verbal abilities is unknown; however, in patients with a low verbal IQ and early seizure onset, these areas appear to be less critical for language processing.


1982 ◽  
Vol 56 (1) ◽  
pp. 131-134 ◽  
Author(s):  
Hiroshi Yuasa ◽  
Sumitaka Tokito ◽  
Kazuo Izumi ◽  
Kazuaki Hirabayashi

✓ A 51-year-old woman became unconscious 19 hours after the onset of a headache. Computerized tomography disclosed an intracerebral hematoma in the left temporal lobe, with ventricular penetration. Angiography demonstrated the characteristic appearance of cerebrovascular moyamoya disease as well as an aneurysm-like shadow in the left temporal lobe, which proved on histological examination to be a pseudoaneurysm.


1976 ◽  
Vol 44 (6) ◽  
pp. 712-714 ◽  
Author(s):  
Norman Chater ◽  
Robert Spetzler ◽  
Kent Tonnemacher ◽  
Charles B. Wilson

✓ Microvascular anatomical studies were performed to ascertain the most suitable cortical vessel for extracranial-intracranial arterial bypass (EIAB). The three most commonly used cortical areas (the tip of the frontal lobe, the tip of the temporal lobe, and the area at the angular gyrus) were examined in detail. Because of their accessibility and size, the cortical arteries in the area of the angular gyrus offer the most suitable location for creating an EIAB.


1984 ◽  
Vol 60 (3) ◽  
pp. 457-466 ◽  
Author(s):  
Sidney Goldring ◽  
Erik M. Gregorie

✓ One hundred patients with focal epilepsy (44 were children) were evaluated with extraoperative electrocorticography via epidural electrode arrays. Localization of the epileptogenic focus was derived predominantly from recordings made during spontaneously occurring seizures. All resection procedures were carried out under general anesthesia. During anesthesia, the recording of sensory evoked responses made it possible to readily identify the sensorimotor region. Of the 100 patients, 72 underwent resection of an epileptogenic focus, and 33 of these were children. Those who did not have a resection either exhibited a diffuse seizure focus, failed to show an electrical seizure discharge in association with the clinical seizure, failed to have a seizure during the period of monitoring, or failed to exhibit conclusive changes for identifying a focus in the interictal record. Fifty-seven patients (29 children and 28 adults) who had a resection have been followed for between 1 and 12 years. Eighteen (62%) of the 29 children and 18 (64%) of the 28 adults enjoyed a good result. Twenty of the 100 patients reported here had temporal lobe epilepsy. They were candidates for recordings with depth electrodes to identify their focus, but they were evaluated instead with epidural recordings; the method is described. In 15 of them, a unilateral focus was identified and they underwent an anterior temporal lobectomy. Pathological changes were found in every case and, in 11 patients, the epidural recordings distinguished between a medial and a lateral focus. Ten of these patients have been followed for 9 months to 3½ years, and seven have had a good result. The observations suggest that epidural electrodes may be used in lieu of depth electrodes for identifying the symptomatic temporal lobe.


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