Anatomical analysis of different hemispherotomy procedures based on dissection of cadaveric brains

2002 ◽  
Vol 97 (2) ◽  
pp. 423-431 ◽  
Author(s):  
Michiharu Morino ◽  
Hiroyuki Shimizu ◽  
Kenji Ohata ◽  
Kiyoaki Tanaka ◽  
Mitsuhiro Hara
Keyword(s):  
Internal Capsule ◽  
Brain Anatomy ◽  
Anatomical Landmarks ◽  
Systematic Analysis ◽  
Content Type ◽  
Neuronal Connections ◽  
Acceptable Method ◽  
Human Brains ◽  
Formalin Fixed ◽  
Fine Print

Object. Functional hemispherectomy, itself a modification of anatomical hemispherectomy, has been further modified to a less invasive method (hemispherotomy), in which cortical resection is minimized and the rest of the affected hemisphere is functionally isolated by transecting its projection and commissural fibers. Although descriptions of three different types of hemispherotomy procedures have been published, the authors believe that it is important to develop a common and universally acceptable method based on a systematic analysis of topographic anatomy and neuronal connections. To this end, they have analyzed the three aforementioned procedures on the basis of meticulous fiber dissections in previously frozen formalin-fixed human brains. Methods. The brain anatomy pertinent to surgical hemispherotomy is described in conjunction with dissection studies in 14 previously frozen, formalin-fixed human brains. The anatomical landmarks necessary for performing particular neuronal fiber resections are identified, and their relationships with operative methods are discussed, with an emphasis on commonalities among the three hemispherotomy procedures. Conclusions. In this analysis the authors confirmed that hemispherotomy typically consists of four common procedures: 1) interruption of the internal capsule and corona radiata; 2) resection of the medial temporal structures; 3) transventricular corpus callosotomy; and 4) disruption of the frontal horizontal fibers. After meticulous dissection of cadavers, the authors have designated a reliable method for performing these four operations that may be applicable as a commonly used procedure.

Transkull focal lesions in cat brain produced by ultrasound

1981 ◽  
Vol 54 (5) ◽  
pp. 659-663 ◽  
Author(s):  
Francis J. Fry ◽  
Stephen A. Goss ◽  
James T. Patrick
Keyword(s):  
Focused Ultrasound ◽  
Ultrasonic Beam ◽  
Acoustical Parameters ◽  
Focal Lesions ◽  
Content Type ◽  
Histological Appearance ◽  
Cat Brain ◽  
Ultrasonic Techniques ◽  
Formalin Fixed ◽  
Fine Print

✓ Focused ultrasound has been used for focal modifications of brain tissue and in preliminary studies of the application of ultrasonic techniques for tissue modification in human stereotaxic neurosurgery; however, the technique has been seriously compromised by the necessity of removal of intervening skull. Such removal was necessary to avoid distortion and extremely large attenuation of the ultrasonic beam which resulted from passage through bone. Recent studies have shown that under proper conditions focal beams of ultrasound can be transmitted with tolerable distortion and attenuation through skull, suggesting the possibility of transkull lesion production in brain. This report describes the acoustical parameters and histological features of focal brain lesions produced in 10 craniectomized cats with intense focal ultrasonic beams which first had passed through a formalin-fixed human skull overlay. The histological appearance of these lesions produced to date is similar to that produced previously without intervening skull.

Quadrant anatomy of the articular pillars (lateral cervical mass) of the cervical spine

1995 ◽  
Vol 82 (6) ◽  
pp. 1011-1014 ◽  
Author(s):  
T. Glenn Pait ◽  
Phillip V. McAllister ◽  
Howard H. Kaufman
Keyword(s):  
Anatomical Landmarks ◽  
Cervical Mass ◽  
Content Type ◽  
Bony Landmarks ◽  
Fixation Devices ◽  
Human Cadavers ◽  
Lateral Mass Screws ◽  
Neurovascular Structures ◽  
Lateral Facet ◽  
Fine Print

✓ Knowledge of the relevant anatomy is important when developing a strategy for introducing screws into the lateral masses to secure internal fixation devices. This paper defines key bony landmarks and their relationship to critical neurovascular structures and identifies a location for safe placement of cervical articular pillar (lateral mass) screws. Measurements of anatomical landmarks in 10 spines from human cadavers aged 61 to 85 years were made by caliper and a metric ruler. Landmarks were the lateral facet line, rostrocaudal line, medial facet line, intrafacet line, and medial facet line—vertebral artery line. The average distances and ranges were recorded. Such great variance existed in measurements from spine to spine and within the same spine as to render averages clinically unreliable. Dissection revealed that division of the articular pillar into four quadrants leaves one, the superior lateral quadrant, under which there are no neurovascular structures; this may be considered the “safe quadrant” for placement of posterior screws and plates.

Individual variations in the sulcal anatomy of the basal temporal lobe and its relevance for epilepsy surgery: an anatomical study performed using magnetic resonance imaging

2002 ◽  
Vol 96 (3) ◽  
pp. 464-473 ◽  
Author(s):  
Klaus Novak ◽  
Thomas Czech ◽  
Daniela Prayer ◽  
Wolfgang Dietrich ◽  
Wolfgang Serles ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Temporal Lobe ◽  
Anatomical Landmarks ◽  
Resonance Imaging ◽  
Mr Images ◽  
Hippocampal Region ◽  
Content Type ◽  
Individual Variations ◽  
Fine Print

Object. The concept of selective amygdalohippocampectomy is based on pathophysiological insights into the epileptogenicity of the hippocampal region and the definition of the clinical syndrome of mesial temporal lobe epilepsy (TLE). High-resolution magnetic resonance (MR) imaging allows correlation of the site of histologically conspicuous tissue with anatomical structure. The highly variable sulcal pattern of the basal temporal lobe, however, definitely complicates the morphometric analysis of histomorphologically defined subdivisions of the hippocampal region. The goal of this study was to define individual variations in the sulcal anatomy on the basis of preoperative MR images obtained in patients suffering from TLE. Methods. The authors analyzed coronal MR images obtained in 50 patients for the presence of and intrinsic relationships among the rhinal, collateral, and occipitotemporal sulci. The surface relief of consecutive sections of 100 temporal lobes was graphically outlined and the resulting maps were used for visual analysis. The sulci were characterized by measurement of their depth, distance to the temporal horn, and laterality. The anatomical measurements and frequencies of sulcal patterns were assessed for statistical correlation with patients' histories and the lateralization of the seizure focus. Conclusions. Statistical assessment shows that patient sex is a significant factor in sulcal patterns. Anatomical measurements are significantly decreased on the side of the seizure origin, which relates to loss of white matter, a known morphological abnormality associated with TLE. Magnetic resonance imaging allows for accurate preoperative knowledge of individual sulcal patterns and facilitates intraoperative orientation to anatomical landmarks.

The denticulate ligament: anatomy and functional significance

2001 ◽  
Vol 94 (2) ◽  
pp. 271-275 ◽  
Author(s):  
R. Shane Tubbs ◽  
George Salter ◽  
Paul A. Grabb ◽  
W. Jerry Oakes
Keyword(s):  
Spinal Cord ◽  
Functional Significance ◽  
Spinal Canal ◽  
Cervical Region ◽  
Content Type ◽  
Functional Studies ◽  
Applied Tension ◽  
Limited Degree ◽  
Formalin Fixed ◽  
Fine Print

Object. The authors conducted a study to examine the detailed anatomy of the denticulate ligaments and to assess their classic role in spinal cord stability within the spinal canal. Methods. Detailed observation of the denticulate ligaments in 12 adult cadavers was performed. Stress was applied in all major planes to discern when the ligaments would become taut, and at the same time, gross motion of the cord was observed at sites distal to the stresses applied. Tension necessary for avulsion of the ligaments in various areas of the spinal cord was also measured. Conclusions. These results show that the denticulate ligaments do not inhibit cord motion to such discrete areas of the cord as was once thought. The authors have determined that the ligaments are stronger in the cervical region and that they decrease in strength as the spinal cord descends. These findings are demonstrative of the denticulate ligaments being more resistant to caudal compared with cephalad stresses in the cord. Anterior and posterior motion is constrained by these ligaments but to a limited degree, especially as one descends inferiorly along the cord. Further embryological and functional studies of these ligaments is needed in non—formalin fixed tissues.

Mandibular subluxation as an adjunct to exposure of the distal internal carotid artery in endarterectomy surgery

1995 ◽  
Vol 83 (5) ◽  
pp. 926-928 ◽  
Author(s):  
David M. Frim ◽  
Bonnie Padwa ◽  
Deidre Buckley ◽  
Robert M. Crowell ◽  
Christopher S. Ogilvy
Keyword(s):  
Carotid Artery ◽  
Internal Carotid Artery ◽  
Skull Base ◽  
Internal Carotid ◽  
Anatomical Landmarks ◽  
Simple Method ◽  
Content Type ◽  
Anterior Nasal Spine ◽  
Edentulous Patients ◽  
Fine Print

✓ The location of the carotid artery bifurcation and the distance atherosclerotic disease extends distally in the internal carotid artery (ICA) are two factors that contribute to the technical difficulty of carotid endarterectomy. When the bifurcation is high (above C-3) or the disease extends distally, standard approaches may not provide adequate exposure for dissection of plaque or for arteriotomy repair. A simple method of mandibular subluxation is described for added exposure of the distal carotid artery. The criteria for use of this method include: a carotid bifurcation at or above C-2; disease extending to within 2 cm of the skull base; and a small-caliber distal ICA lumen with the expectation of a patch graft extending close to the skull base. In dentulous patients, the mandible is subluxed by attaching an intradental wire from the ipsilateral mandibular bicuspid to an intradental wire around the contralateral maxillary bicuspid. In edentulous patients, a wire is placed around the ipsilateral mandible and secured to a wire placed through the anterior nasal spine. The entire preoperative subluxation requires 10 to 15 minutes under anesthesia and an additional 1 to 2 minutes postoperatively to remove the wires. A single skin suture and an absorbable intraoral suture were placed in some edentulous patients. This technique has been evaluated over a 15-month reference period during which 115 carotid endarterectomies were performed. The criteria stated above were met in seven cases (six patients, 6%) and jaw subluxation was performed preoperatively. An additional 1 to 2 cm of distal exposure was obtained by using this technique and endarterectomy proceeded without complication. A slight “shift” of the standard anatomical landmarks occurred due to the movement of the mandible, which was easily recognized. There were no significant postoperative complaints related to the subluxation; specifically, no temporomandibular joint pain, no other postoperative pain, and no tooth damage were encountered. It is concluded that this relatively simple approach to mandibular subluxation provided significant added exposure to the distal ICA without notably increasing operative time. In addition, there was no morbidity and little additional care was needed when compared with other more radical approaches to high carotid artery exposure.

Comparison of the transvermian and telovelar approaches to the fourth ventricle

2004 ◽  
Vol 101 (3) ◽  
pp. 484-498 ◽  
Author(s):  
Necmettin Tanriover ◽  
Arthur J. Ulm ◽  
Albert L. Rhoton ◽  
Alexandre Yasuda
Keyword(s):  
Fourth Ventricle ◽  
Image Guidance ◽  
Surgical Approaches ◽  
Content Type ◽  
Lateral Recess ◽  
Telovelar Approach ◽  
Additional Exposure ◽  
Formalin Fixed ◽  
Fine Print ◽  
Foramen Of Luschka

Object. The two most common surgical routes to the fourth ventricle are the transvermian and telovelar approaches. The purpose of this study was to compare the microanatomy and exposures gained through these approaches. Methods. Ten formalin-fixed specimens were dissected in a stepwise manner to simulate the transvermian and telovelar surgical approaches. Stealth image guidance was used to compare the exposures and working angles obtained using these approaches. The transvermian and telovelar approaches provided access to the entire rostrocaudal length of the fourth ventricle floor from the aqueduct to the obex. In addition, both approaches provided access to the entire width of the floor of the fourth ventricle. The major difference between the two approaches regarded the exposure of the lateral recess and the foramen of Luschka. The telovelar, but not the transvermian, approach exposed the lateral and superolateral recesses and the foramen of Luschka. The transvermian approach, which offered an incision through at least the lower third of the vermis, afforded a modest increase in the operator's working angle compared with the telovelar approach when accessing the rostral half of the fourth ventricle. Conclusions. The transvermian approach provides slightly better visualization of the medial part of the superior half of the roof of the fourth ventricle. The telovelar approach, which lacks incision of any part of the cerebellum, provides an additional exposure to the lateral recesses and the foramen of Luschka.

Germinoma causing wallerian degeneration

1998 ◽  
Vol 88 (1) ◽  
pp. 126-128 ◽  
Author(s):  
Kiyoshi Nagata ◽  
Yuji Nikaido ◽  
Takashi Yuasa ◽  
Kenta Fujimoto ◽  
Yong Jin Kim ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Basal Ganglia ◽  
Cerebral Hemisphere ◽  
Wallerian Degeneration ◽  
Pathological Change ◽  
Internal Capsule ◽  
Resonance Imaging ◽  
Content Type ◽  
The Brain ◽  
Fine Print

✓ Germinomas occurring in the thalamus and basal ganglia sometimes cause atrophy of the cerebral hemisphere on the affected side. The authors present the case of a 12-year-old girl with a germinoma that developed in the basal frontal lobe and cerebral basal ganglia. Magnetic resonance imaging showed atrophy not only of the cerebrum but also of the brainstem. A T2-weighted image revealed an area of high intensity that proved to be wallerian degeneration extending from the corona radiata and internal capsule to the brainstem. The authors suggest that this pathological change may be involved in the development of the symptoms and hemiatrophy associated with germinomas in this region of the brain.

Subfascial and submuscular methods of temporal muscle dissection and their relationship to the frontalis branch of the facial nerve

2000 ◽  
Vol 92 (5) ◽  
pp. 877-880 ◽  
Author(s):  
Ernesto Coscarella ◽  
A. Giancarlo Vishteh ◽  
Robert F. Spetzler ◽  
Eduardo Seoane ◽  
Joseph M. Zabramski
Keyword(s):  
Facial Nerve ◽  
Superficial Temporal Artery ◽  
Temporal Artery ◽  
Microsurgical Anatomy ◽  
Anatomical Landmarks ◽  
Temporal Muscle ◽  
Content Type ◽  
Dissection Technique ◽  
Frontal Branch ◽  
Fine Print

✓ The microsurgical anatomy of the temporal and zygomatic branches of the facial nerve are presented along with related local vasculature (frontal and parietal branches of the superficial temporal artery [STA]) as encountered when using subfascial and submuscular temporal muscle dissection techniques for anterolateral craniotomies.Twenty sides were studied in 10 cadaveric specimens that had been previously injected with latex. The rami of the temporal and zygomatic branches of the facial nerve and branches of the STA were dissected out through pterional and orbitozygomatic approaches by using a submuscular or subfascial temporal muscle dissection technique.The three rami of the temporal branch of the facial nerve (the auricularis, frontalis, and orbicularis) were found to run within the galeal plane of the scalp. The zygomatic branch of the facial nerve was found to course deeper than the most caudal extension of the galea, known as the superficial musculoaponeurotic layer. The frontal branch of the STA served as an important landmark for the subfascial or submuscular dissections because excessive reflection of the scalp flap inferior to the level of this vessel would inadvertently injure the frontalis branch of the facial nerve.Subfascial and submuscular dissections of the temporal muscle offer an alternative to the interfascial technique during anterolateral craniotomies. Scalp and temporal dissection performed with careful attention to anatomical landmarks (frontal branch of the STA and the suprafascial fat pad) provides a safe and expeditious alternative to the traditional interfascial technique.

Anatomical landmarks for hemispherotomy and their clinical application

2004 ◽  
Vol 101 (5) ◽  
pp. 747-755 ◽  
Author(s):  
Hung Tzu Wen ◽  
Albert L. Rhoton ◽  
Raul Marino
Keyword(s):  
Corpus Callosum ◽  
Choroid Plexus ◽  
Frontal Lobe ◽  
Lateral Surface ◽  
Lateral Ventricle ◽  
Central Core ◽  
Anatomical Landmarks ◽  
Content Type ◽  
Occipital Lobes ◽  
Fine Print

Object. The authors introduce the surgical concept of the central core of a hemisphere, from which anatomical structures are disconnected during most current hemispherotomy techniques. They also propose key anatomical landmarks for hemispherotomies that can be used to disconnect the hemisphere from its lateral surface around the insula, through the lateral ventricle toward the midline. Methods. This anatomical study was performed in five adult cadaveric heads following perfusion of the cerebral arteries and veins with colored latex. Anatomical landmarks were used in five hemispheric deafferentations. The central core of a hemisphere consists of extreme, external, and internal capsules; claustrum; lentiform and caudate nuclei; and thalamus. Externally, this core is covered by the insula and surrounded by the fornix, choroid plexus, and lateral ventricle. During most hemispherotomies, the surgeon reaches the lateral ventricle through the frontoparietal opercula or temporal lobe; removes the mesial temporal structures; and disconnects the frontal lobe ahead, the parietal and occipital lobes behind, and the intraventricular fibers of the corpus callosum above the central core. After a temporal lobectomy, the landmarks include the choroid plexus and posterior/ascending portion of the tentorium to disconnect the parietal and occipital lobes, the callosal sulcus or distal anterior cerebral artery (ACA) to sever the intraventricular fibers of the corpus callosum, and the head of the caudate nucleus and ACA to detach the frontal lobe. Conclusions. These landmarks can be used in any hemispherotomy during which a cerebral hemisphere is disconnected from its lateral surface. Furthermore, they can be used to perform any resection around the central core of the hemisphere and the tentorial incisura.

Diffuse axonal injury in mild traumatic brain injury: a diffusion tensor imaging study

2005 ◽  
Vol 103 (2) ◽  
pp. 298-303 ◽  
Author(s):  
Matilde Inglese ◽  
Sachin Makani ◽  
Glyn Johnson ◽  
Benjamin A. Cohen ◽  
Jonathan A. Silver ◽  
...  
Keyword(s):  
Diffusion Tensor Imaging ◽  
Mr Imaging ◽  
Fractional Anisotropy ◽  
Diffusion Tensor ◽  
Axonal Injury ◽  
Diffuse Axonal Injury ◽  
Mean Diffusivity ◽  
Internal Capsule ◽  
Content Type ◽  
Fine Print

Object. Diffuse axonal injury (DAI) is a major complication of traumatic brain injury (TBI) that leads to functional and psychological deficits. Although DAI is frequently underdiagnosed by conventional imaging modalities, it can be demonstrated using diffusion tensor imaging. The aim of this study was to assess the presence and extent of DAI in patients with mild TBI. Methods. Forty-six patients with mild TBI and 29 healthy volunteers underwent a magnetic resonance (MR) imaging protocol including: dual—spin echo, fluid-attenuated inversion recovery, T2-weighted gradient echo, and diffusion tensor imaging sequences. In 20 of the patients, MR imaging was performed at a mean of 4.05 days after injury. In the remaining 26, MR imaging was performed at a mean of 5.7 years after injury. In each case, mean diffusivity and fractional anisotropy were measured using both whole-brain histograms and regions of interest analysis. No differences in any of the histogram-derived measures were found between patients and control volunteers. Compared with controls, a significant reduction of fractional anisotropy was observed in patients' corpus callosum, internal capsule, and centrum semiovale, and there were significant increases of mean diffusivity in the corpus callosum and internal capsule. Neither histogram-derived nor regional diffusion tensor imaging metrics differed between the two groups. Conclusions. Although mean diffusivity and fractional anisotropy abnormalities in these patients with TBI were too subtle to be detected with the whole-brain histogram analysis, they are present in brain areas that are frequent sites of DAI. Because diffusion tensor imaging changes are present at both early and late time points following injury, they may represent an early indicator and a prognostic measure of subsequent brain damage.

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