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1.
J Clin Neurosci ; 89: 226-231, 2021 Jul.
Article in English | MEDLINE | ID: mdl-34119272

ABSTRACT

We describe the anatomical landmarks and surgical feasibility of a novel 'safe' brainstem entry zone to approach ventrally placed intra-axial midbrain tumors. The anatomy of the brainstem was specifically studied to evaluate safe surgical entry zone in the midbrain on two formalin fixed silicon injected cadaver head specimens. A novel entry point through the lateral one - fifth of the cerebral peduncle was identified to be 'safe' to approach lesions of the ventral midbrain. Three patients, having oculomotor schwannoma, peduncular glioma and a peduncular cavernoma were operated using this safe entry zone. To approach the midbrain, retrosigmoid lateral supracerebellar route was used in two patients and a basal subtemporal avenue was deployed in one patient. On the basis of fine microanatomical dissection on cadavers, a novel entry point through the lateral one-fifth of the cerebral peduncle, 5 mm anterior to the lateral mesencephalic sulcus and approximately 5 mm superior to the fourth nerve was identified. The proposed brainstem entry point traverses the parieto-temporo-occipital pontine fibers and the trajectory is between the corticospinal tracts ventrally and the substantia nigra dorsally. Three patients were operated successfully using the approach. There were no post-operative motor, sensory or extra-pyramidal deficits. The corridor through the lateral one-fifth of the cerebral peduncle presents a safe and relative 'easy' surgical route to approach ventrally placed intra-axial midbrain tumors.


Subject(s)
Brain Stem Neoplasms/diagnostic imaging , Brain Stem Neoplasms/surgery , Cerebral Peduncle/diagnostic imaging , Cerebral Peduncle/surgery , Craniotomy/methods , Microsurgery/methods , Adult , Cadaver , Female , Humans , Male , Young Adult
2.
World Neurosurg ; 140: e41-e45, 2020 08.
Article in English | MEDLINE | ID: mdl-32311564

ABSTRACT

BACKGROUND: Lesions arising at the ventral thalamopeduncular junction are difficult to resect. In addition to being relatively inaccessible, these lesions are located in one of the most sensitive areas of the brain. A critical question is whether new approaches could be developed to allow surgeons to adequately resect these lesions with reasonable outcomes. In the present report, we describe our approach to resect lesions in this region of the brain using an eyebrow craniotomy approach with a trajectory through the supracarotid triangle. METHODS: Through retrospective data collection, we present a small series of patients who had undergone an eyebrow, supracarotid triangle approach to resect lesions located at the thalamopeduncular junction. We describe our surgical technique and report patient outcomes using this approach. RESULTS: Three patients had undergone an eyebrow, supracarotid approach for resection of a lesion arising at the ventral thalamopeduncular junction. Two patients had presented with a cavernoma and one with a pilocytic astrocytoma. Complete resection of all 3 lesions was achieved during surgery without any intraoperative complications. No patient developed permanent contralateral weakness despite entering the peduncle during surgery. One patient developed permanent paresthesia in his left hand. CONCLUSIONS: Lesions arising at the ventral thalamopeduncular junction can be adequately resected with reasonable outcomes using an eyebrow, supracarotid triangle approach. This operative technique establishes another potential operative corridor by which neurosurgeons can resect lesions arising within this relatively inaccessible part of the brain.


Subject(s)
Astrocytoma/surgery , Brain Stem Neoplasms/surgery , Cerebral Peduncle/surgery , Craniotomy/methods , Eyebrows , Thalamus/surgery , Adult , Astrocytoma/diagnostic imaging , Brain Stem Neoplasms/diagnostic imaging , Cerebral Peduncle/diagnostic imaging , Female , Humans , Male , Retrospective Studies , Thalamus/diagnostic imaging , Young Adult
3.
Neurosurg Rev ; 42(1): 155-161, 2019 Mar.
Article in English | MEDLINE | ID: mdl-29623480

ABSTRACT

There are still different descriptions of the segmentation of the posterior cerebral artery, although there is a radiological and anatomical consensus on the segmentation of the anterior and the middle cerebral artery. This study aims to define the most appropriate localization for origin and end points of the segments through reviewing the segmentation of the posterior cerebral artery. The segments and the cortical branches originating from those segments of the 40 posterior cerebral arteries of 20 cadaver brains were examined under operating microscope. In this research, the P1, P2, P3, P4, and P5 classification of the segmentation of the posterior cerebral artery is redefined. This redefinition was made to overcome the complexities of previous definitions. The P1 segment in this research takes its origin from the basilar tip and ends at the junction with the posterior communicating artery. The average diameter of this segment at the origin was 2.21 mm (0.9-3.3), and the average length was 6.8 mm (3-12). The P2 segment extends from the junction with the posterior communicating artery to the origin of the lateral temporal trunk. This point usually situates on one level of posterior of the cerebral peduncle. The average diameter of this segment at the origin was 2.32 mm (1.3-3.1), and the average length was 20.1 mm (11-26). The P3 segment extends from the origin of the lateral temporal trunk to the colliculus where both the posterior cerebral arteries are the nearest to each other (quadrigeminal point) and is located at the anterior-inferior of the splenium. The average diameter of this segment at the origin was 1.85 mm (1.2-2.7), and the average length was 16.39 mm (9-28). The P4 begins at the quadrigeminal point and ends at the top of the cuneus. The average diameter of this segment at the origin was 1.55 mm (1.1-2.2). While the P5 segment is named as the terminal branches of the major terminal branches of the posterior cerebral artery, no definite border was found between the P4 and the P5 segments. In this study, the segmentation of the posterior cerebral artery, developed by Krayenbühl and Yasargil, was redefined to be more appropriate for radiological and anatomical purposes.


Subject(s)
Microsurgery , Posterior Cerebral Artery/anatomy & histology , Posterior Cerebral Artery/surgery , Aged , Aged, 80 and over , Basilar Artery/anatomy & histology , Basilar Artery/surgery , Cadaver , Cerebral Arteries/anatomy & histology , Cerebral Arteries/surgery , Cerebral Peduncle/anatomy & histology , Cerebral Peduncle/surgery , Female , Humans , Male , Middle Aged , Neurosurgical Procedures/methods , Occipital Lobe/anatomy & histology , Occipital Lobe/surgery , Superior Colliculi/anatomy & histology , Superior Colliculi/surgery
4.
Acta Neurochir (Wien) ; 159(9): 1597-1601, 2017 Sep.
Article in English | MEDLINE | ID: mdl-28674731

ABSTRACT

BACKGROUND: Thalamopeduncular tumors arise at the junction of the inferior thalamus and cerebral peduncle, and present with a common clinical syndrome of progressive spastic hemiparesis. METHOD: Formal preoperative magnetic resonance imaging (MRI) and diffusion tensor imaging (DTI) were performed. Postoperative MRI was obtained to evaluate the extent of tumor resection. A prospective analysis of clinical outcomes was then conducted by the senior author. CONCLUSIONS: Preoperative tractography is a useful adjunct to surgical planning in tumors that displace motor pathways. Gross total resection of pilocytic astrocytomas usually results in cure, and therefore should be entertained when developing treatment strategies for thalamopeduncular tumors of childhood.


Subject(s)
Astrocytoma/surgery , Brain Neoplasms/surgery , Cerebral Peduncle/surgery , Neurosurgical Procedures/methods , Surgery, Computer-Assisted/methods , Thalamic Diseases/surgery , Adult , Astrocytoma/diagnostic imaging , Brain Neoplasms/diagnostic imaging , Cerebral Peduncle/diagnostic imaging , Child , Diffusion Tensor Imaging/methods , Humans , Magnetic Resonance Imaging , Prospective Studies , Thalamic Diseases/diagnostic imaging
5.
Clin Neurol Neurosurg ; 156: 35-40, 2017 May.
Article in English | MEDLINE | ID: mdl-28292695

ABSTRACT

OBJECTIVE: The Klingler fiber dissection technique is a relevant and reliable method for neurosurgery to identify with accuracy the fine structure of the brain anatomy highlighting white matter tracts. In order to demonstrate the significance of the application of this technique, we aimed to observe the course and relations of the mammillothalamic and habenulo-interpeduncular tracts as there are very few papers showing these important diencephalic tracts. MATERIAL AND METHODS: Twelve formalin-fixed brains were dissected using the Klingler technique in order to expose the medial diencephalic surface. Diencephalic white matter tracts, particularly the mammillothalamic and habenulo-interpeduncular tracts, were dissected using wooden spatulas and metallic dissectors with different sizes and tips. Several measurements were performed in both dissected hemispheres relative to the mammillothalamic and habenulo-interpeduncular tracts. RESULTS: The course and length of these two tracts were visualized and the relations with other fiber systems and with the neighboring gray matter structures quantified and registered. The mammillothalamic tract approximately marks the anteroposterior coordinate of the anterior pole of the subthalamic nucleus in the anterior commissure - posterior commissure plane. CONCLUSION: The present study helps to understand the three-dimensional architecture of the white matter systems of tracts when the Klingler technique is used. The numerical data obtained may be helpful to neurosurgeons while approaching brain paraventricular and ventricular lesions and deep brain stimulation. Finally, the anatomical knowledge can lower surgical complications and improve patient care particularly in the field of neurosurgery.


Subject(s)
Diencephalon/anatomy & histology , Diencephalon/surgery , Neurosurgical Procedures/methods , Pyramidal Tracts/anatomy & histology , Pyramidal Tracts/surgery , White Matter/anatomy & histology , White Matter/surgery , Cadaver , Cerebral Peduncle/anatomy & histology , Cerebral Peduncle/surgery , Dissection/methods , Habenula/anatomy & histology , Habenula/surgery , Humans , Mammillary Bodies/anatomy & histology , Mammillary Bodies/surgery , Thalamus/anatomy & histology , Thalamus/surgery , Tissue Fixation
6.
World Neurosurg ; 98: 463-469, 2017 Feb.
Article in English | MEDLINE | ID: mdl-27888085

ABSTRACT

OBJECTIVE: Thalamopeduncular tumors (TPTs) of childhood present a challenge for neurosurgeons due to their eloquent location. Preoperative fiber tracking provides total or near-total resection, without additional neurologic deficit. High-definition fiber tractography (HDFT) is an advanced white matter imaging technique derived from magnetic resonance imaging diffusion data, shown to overcome the limitations of diffusion tensor imaging. We aimed to investigate alterations of corticospinal tract (CST) and medial lemniscus (ML) caused by TPTs and to demonstrate the application of HDFT in preoperative planning. METHODS: Three pediatric patients with TPTs were enrolled. CSTs and MLs were evaluated for displacement, infiltration, and disruption. The relationship of these tracts to tumors was identified and guided surgical planning. Literature was reviewed for publications on pediatric thalamic and TPTs that used diffusion imaging. RESULTS: Two patients had histologic diagnosis of pilocytic astrocytoma. One patient whose imaging suggested a low-grade glioma was managed conservatively. All tracts were displaced (1 CST anteriorly, 2 CSTs, 1 ML anteromedially, 1 ML medially, and 1 ML posteromedially). Literature review revealed 2 publications with 15 pilocytic astrocytoma cases, which investigated CST only. The condition of sensory pathway or anteromedial displacement of the CST in these tumors was not reported previously. CONCLUSIONS: Displacement patterns of the perilesional fiber bundles by TPTs are not predictable. Fiber tracking, preferably HDFT, should be part of preoperative planning to achieve maximal extent of resection for longer survival rates in this young group of patients, while preserving white matter tracts and thus quality of life.


Subject(s)
Astrocytoma/pathology , Brain Neoplasms/pathology , Adolescent , Astrocytoma/surgery , Cerebral Peduncle/pathology , Cerebral Peduncle/surgery , Child, Preschool , Diffusion Tensor Imaging/methods , Female , Humans , Leukoencephalopathies/pathology , Leukoencephalopathies/surgery , Magnetic Resonance Imaging/methods , Patient Care Planning , Surgery, Computer-Assisted/methods , Thalamic Diseases/pathology , Thalamic Diseases/surgery , Treatment Outcome
7.
Stereotact Funct Neurosurg ; 93(1): 38-41, 2015.
Article in English | MEDLINE | ID: mdl-25662091

ABSTRACT

BACKGROUND/OBJECTIVE: Decisions to use open surgery or radiotherapy in pediatric patients with familial neoplastic syndromes must consider not only the symptomatic benefits of treatment, but also future limitations these treatments may impose. Specifically, open surgical resection of noncurable tumors may preclude or encumber future lesion resections, while radiotherapy has detrimental effects on pediatric cognitive development and increases the risk of future malignancy development. We provide the first report of using a novel 3.0-mm diffusing laser tip with laser-induced thermal therapy (LiTT) to treat a pediatric patient with neurofibromatosis type 1 (NF-1). METHODS: A 12-year-old boy with NF-1 presented with a progressively enlarging lesion in the right midbrain. A stereotactic biopsy was performed, followed by LiTT with a novel 3.0-mm laser applicator. RESULTS: MRI 1 week after LiTT showed stable gross total ablation of the lesion with reduction in fluid-attenuated inversion recovery signal. The patient remained neurologically intact 6 months after his procedure, and follow-up MRI showed no evidence of recurrence. CONCLUSION: LiTT is a powerful adjunct to conventional open surgical and radiotherapy modalities in the treatment of patients with familial neoplastic syndromes or incurable lesions. The novel laser applicator tip described expands the treatment scope of this technique.


Subject(s)
Cerebral Peduncle/surgery , Glioma/surgery , Infratentorial Neoplasms/surgery , Laser Therapy/instrumentation , Neurofibromatosis 1/surgery , Antineoplastic Combined Chemotherapy Protocols/therapeutic use , Astrocytoma/drug therapy , Astrocytoma/radiotherapy , Bevacizumab/administration & dosage , Camptothecin/administration & dosage , Camptothecin/analogs & derivatives , Child , Combined Modality Therapy , Dacarbazine/administration & dosage , Dacarbazine/analogs & derivatives , Glioma/genetics , Humans , Infratentorial Neoplasms/genetics , Irinotecan , Laser Therapy/methods , Male , Neoplasms, Multiple Primary/radiotherapy , Neoplasms, Multiple Primary/surgery , Neuroimaging , Optic Nerve Glioma/radiotherapy , Supratentorial Neoplasms/drug therapy , Supratentorial Neoplasms/radiotherapy , Temozolomide
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