Morphologic Variations of the Collateral Sulcus on the Mediobasal Region of the Temporal Lobe: An Anatomical Study

OBJECTIVE Conventional approaches to the atrium of the lateral ventricle may be associated with complications related to direct cortical injury or brain retraction. The authors describe a novel approach to the atrium through a retrosigmoid transtentorial transcollateral sulcus corridor. METHODS Bilateral retrosigmoid craniotomies were performed on 4 formalin-fixed, colored latex–injected human cadaver heads (a total of 8 approaches). Microsurgical dissections were performed under 3× to 24× magnification, and endoscopic visualization was provided by 0° and 30° rigid endoscope lens systems. Image guidance was provided by coupling an electromagnetic tracking system with an open source software platform. Objective measurements on cortical thickness traversed and total depth of exposure were recorded. Additionally, the basal occipitotemporal surfaces of 10 separate cerebral hemisphere specimens were examined to define the surface topography of sulci and gyri, with attention to the appearance and anatomical patterns and variations of the collateral sulcus and the surrounding gyri. RESULTS The retrosigmoid approach allowed for clear visualization of the basal occipitotemporal surface. The collateral sulcus was identified and permitted easy endoscopic access to the ventricular atrium. The conical corridor thus obtained provided an average base working area of 3.9 cm2 at an average depth of 4.5 cm. The mean cortical thickness traversed to enter the ventricle was 1.4 cm. The intraventricular anatomy of the ipsilateral ventricle was defined clearly in all 8 exposures in this manner. The anatomy of the basal occipitotemporal surface, observed in a total of 18 hemispheres, showed a consistent pattern, with the collateral sulcus abutted by the parahippocampal gyrus medially, and the fusiform and lingual gyrus laterally. The collateral sulcus was found to be caudally bifurcated in 14 of the 18 specimens. CONCLUSIONS The retrosigmoid supracerebellar transtentorial transcollateral sulcus approach is technically feasible. This approach has the potential advantage of providing a short and direct path to the atrium, hence avoiding violation of deep neurovascular structures and preserving eloquent areas. Although this approach appears unconventional, it may provide a minimally invasive option for the surgical management of selected lesions within the atrium of the lateral ventricle.

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The temporoinsular projection system: an anatomical study

Journal of Neurosurgery ◽

10.3171/2018.11.jns18679 ◽

2020 ◽

Vol 132 (2) ◽

pp. 615-623 ◽

Cited By ~ 3

Author(s):

Pieter Nachtergaele ◽

Ahmed Radwan ◽

Stijn Swinnen ◽

Thomas Decramer ◽

Mats Uytterhoeven ◽

...

Keyword(s):

White Matter ◽

Temporal Lobe ◽

Insular Cortex ◽

Anatomical Study ◽

Amygdaloid Complex ◽

Projection System ◽

Temporal Pole ◽

Fiber Dissection ◽

Mesial Temporal Lobe ◽

Association Fibers

OBJECTIVEConnections between the insular cortex and the amygdaloid complex have been demonstrated using various techniques. Although functionally well connected, the precise anatomical substrate through which the amygdaloid complex and the insula are wired remains unknown. In 1960, Klingler briefly described the “fasciculus amygdaloinsularis,” a white matter tract connecting the posterior insula with the amygdala. The existence of such a fasciculus seems likely but has not been firmly established, and the reported literature does not include a thorough description and documentation of its anatomy. In this fiber dissection study the authors sought to elucidate the pathway connecting the insular cortex and the mesial temporal lobe.METHODSFourteen brain specimens obtained at routine autopsy were dissected according to Klingler’s fiber dissection technique. After fixation and freezing, anatomical dissections were performed in a stepwise progressive fashion.RESULTSThe insula is connected with the opercula of the frontal, parietal, and temporal lobes through the extreme capsule, which represents a network of short association fibers. At the limen insulae, white matter fibers from the extreme capsule converge and loop around the uncinate fasciculus toward the temporal pole and the mesial temporal lobe, including the amygdaloid complex.CONCLUSIONSThe insula and the mesial temporal lobe are directly connected through white matter fibers in the extreme capsule, resulting in the appearance of a single amygdaloinsular fasciculus. This apparent fasciculus is part of the broader network of short association fibers of the extreme capsule, which connects the entire insular cortex with the temporal pole and the amygdaloid complex. The authors propose the term “temporoinsular projection system” (TIPS) for this complex.

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Prevalence of the Anterior Occipital Sulcus in the Human Brain: Anatomical Study

Journal of King Abdulaziz University-Medical Sciences ◽

10.4197/med.23-1.3 ◽

2016 ◽

Vol 23 (1) ◽

pp. 19-22

Author(s):

Bassam MJ Addas

Keyword(s):

Human Brain ◽

Temporal Lobe ◽

External Surface ◽

Anatomical Study ◽

Occipital Lobe ◽

The Mean ◽

The Right ◽

Human Brains ◽

Formalin Fixed

The objective of this article is to investigate the prevalence of the anterior occipital sulcus in the human brain. The external surface of 25 consecutive formalin fixed brains (50 hemispheres) were examined for the presence of the anterior occipital sulcus. The anterior occipital sulcus was identified in 11 (22%) hemispheres, seven on the right side and four on the left side. The sulcus length ranged from 1-5 cm with a mean length of 2.89 cm. The mean distance from the occipital lobe tip to the anterior occipital sulcus was 4.75 cm on the right side and 5 cm on the left side. The anterior occipital sulcus can be infrequently encountered in human brains (22%); when present it represents the posterior limit of the temporal lobe and the anterior limit of the occipital lobe.

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Anatomical study of cerebral asymmetry in the temporal lobe of humans, chimpanzees, and rhesus monkeys

Science ◽

10.1126/science.816005 ◽

1976 ◽

Vol 192 (4237) ◽

pp. 387-389 ◽

Cited By ~ 290

Author(s):

G. Yeni-Komshian ◽

D. Benson

Keyword(s):

Temporal Lobe ◽

Rhesus Monkeys ◽

Anatomical Study ◽

Cerebral Asymmetry

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Mesial temporal lobe morphology in intractable pediatric epilepsy: so-called hippocampal malrotation, associated findings, and relevance to presurgical assessment

Journal of Neurosurgery Pediatrics ◽

10.3171/2015.11.peds15485 ◽

2016 ◽

Vol 17 (6) ◽

pp. 683-693 ◽

Cited By ~ 2

Author(s):

James L. Leach ◽

Reem Awwad ◽

Hansel M. Greiner ◽

Jennifer J. Vannest ◽

Lili Miles ◽

...

Keyword(s):

Temporal Lobe ◽

Hippocampal Sclerosis ◽

Brain Mri ◽

Group Analysis ◽

Intractable Epilepsy ◽

Imaging Features ◽

Imaging Findings ◽

Number Of Patients ◽

Collateral Sulcus ◽

Mesial Temporal Lobe

OBJECTIVE Diagnostic criteria for hippocampal malrotation (HIMAL) on brain MRI typically include a rounded hippocampus, vertical collateral sulcus, and architectural blurring. Relationship to epileptogenesis remains speculative, and usefulness for surgical guidance is unknown. The study was performed to determine the prevalence of hippocampal rotational anomalies in a cohort of pediatric patients with intractable epilepsy undergoing evaluation for surgery and to determine the significance of this finding in the context of surgical planning. METHODS Forty-eight surgically treated children with intractable epilepsy were compared with matched healthy subjects; reviewers were blinded to surgical side. Each temporal lobe was evaluated for rounded hippocampus, blurring, vertical collateral sulcus, wide choroidal fissure, enlarged temporal horn, low fornix, hippocampal signal, and findings of hippocampal sclerosis. A mesial temporal lobe (MTL) score was calculated by summing the number of features, and the collateral sulcus angle (CSA) was measured in each temporal lobe. Surgical side, pathological diagnosis, and imaging findings elsewhere in the brain were tabulated. Presence of HIMAL, associated imaging features, and MTL score were compared between sides, between epilepsy and control groups, in relationship to side of surgery, and in relationship to postoperative outcome. RESULTS Only 3 epilepsy patients (6.2%) and no controls exhibited all 3 features of HIMAL (p = 0.12). Eight of 48 (16.7%) epilepsy versus 2 of 48 (4.6%) control subjects had both a rounded hippocampus and vertical collateral sulcus (suggesting HIMAL) (p = 0.045). In control and epilepsy subjects, most findings were more prevalent on the left, and the left CSA was more vertical (p < 0.0001). Epilepsy subjects had higher MTL scores (z = −2.95, p = 0.002) and more acute CSAs (p = 0.04) than controls. Only lateralizing raw MTL score had a significant association with surgical side (p = 0.03, OR 7.33); however, this was not significant when hippocampal sclerosis cases were excluded. HIMAL findings were more prevalent and MTL scores were higher in patients with resections involving the temporal lobes. On group analysis, HIMAL findings did not predict eventual surgical side and did not predict outcome, although the numbers are small. In 4 patients the abnormally rotated hippocampus was resected and showed hippocampal sclerosis and/or dysplastic changes on histopathology. All of these patients had a good outcome after surgery. CONCLUSIONS While increased in prevalence in children with intractable epilepsy, imaging findings of HIMAL did not have preoperative lateralizing utility in this group. Findings of HIMAL (including round hippocampus, architectural blurring, and vertical collateral sulcus) did not predict outcome after surgery, although the small number of patients with these findings limits evaluation. In the small number of patients in which the malrotated hippocampus was removed, outcome was good. Further research is needed to continue to define this association in children with intractable epilepsy, focusing on a temporal lobe cohort.

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Anatomo-radiologic Correlation of the Mesial Aspect of the Temporal Lobe and its Application to Epilepsy Surgery

International Journal of Medical and Surgical Sciences ◽

10.32457/ijmss.2014.038 ◽

2018 ◽

Vol 1 (4) ◽

pp. 311-318

Author(s):

Alejandra Jaume ◽

Federico Salle ◽

Pablo Pereda ◽

Fernando Martínez ◽

Nicolas Sgarbi ◽

...

Keyword(s):

Surgical Treatment ◽

Temporal Lobe ◽

Epilepsy Surgery ◽

Surgical Approach ◽

Parahippocampal Gyrus ◽

Topographic Anatomy ◽

Treatment Of Epilepsy ◽

Collateral Sulcus ◽

Formalin Fixed

The study of the mesial aspect has gained importance due to its anatomic complexity and its relationship to the surgical treatment of epilepsy. The aim of this paper is to do an anatomo-radiologic correlation of the morphology and topography of the mesial aspect of the temporal lobe, with its neurosurgical application in the treatment of diseases in the region. Eight (8) adult formalin fixed hemispheres with no pathologic signs were studied. On 4 of them sections within the 3 planes were performed (sagittal, coronal and axial), for radiologic correlation. On the remaining 4, dissection of the mesial region was done, in order to correlate the structures found during surgical approach to the region. Both in the cadaveric hemispheres and in the radiologic images, structures from the mesial region were identified, this included: collateral sulcus, rinal sulcus, parahippocampal gyrus, temporal uncus, hippocampal sulcus, hippocampus with its 3 sectors (head, body and tail), the inferior choroidal point and the collicular point that divides the hippocampus intro 3 sectors (anterior, medium and posterior). With the results obtained, the principal anamoto- radiologic aspects of the approach to the mesial aspect of the temporal lobe were analyzed, comparing them with results of previous reports. The proper knowledge of both morphologic and topographic anatomy of the mesial aspect of the temporal lobe is crucial for both interpreting radiologic studies and a correct surgical approach for surgical treatment of epilepsy.

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Supratentorial—infraoccipital approach for posteromedial temporal lobe lesions

Journal of Neurosurgery ◽

10.3171/jns.1995.82.6.0940 ◽

1995 ◽

Vol 82 (6) ◽

pp. 940-944 ◽

Cited By ~ 40

Author(s):

Kris A. Smith ◽

Robert F. Spetzler

Keyword(s):

Temporal Lobe ◽

Medial Temporal Lobe ◽

Anatomical Study ◽

Subtotal Resection ◽

Low Grade ◽

Microsurgical Anatomy ◽

Content Type ◽

Anticonvulsant Medication ◽

Navigational System ◽

Temporal Lobe Lesions

✓ The use of the supratentorial—infraoccipital approach is reported in seven patients with posteromedial temporal lobe lesions. No patient had permanent morbidity. Gross total resection of three low-grade gliomas and two gangliogliomas was achieved in five patients; one patient had subtotal resection of a low-grade glioma with adjacent gliosis, and one was initially thought to have a glioma but proved to have encephalomalacia on final pathological analysis. The patients ranged in age from 5 to 34 years. All seven patients presented with seizures, and four had uncontrolled seizures preoperatively. Six have been seizure-free since surgery (mean follow-up period 15 months), and one is well controlled on anticonvulsant medication. An anatomical study was performed to delineate the microsurgical anatomy relevant to operating on the medial temporal lobe through this posterior approach. A viewing wand intraoperative navigational system was utilized with this approach and proved helpful in gaining access as far anterior as the uncus through this occipital craniotomy. This approach is favorable in selected patients with posterior, medial, temporal lobe tumors because resection of otherwise difficult lesions may be accomplished without sacrificing lateral temporal lobe cortex or transecting the optic radiations.

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