Pontomesencephalic Junction Research Articles

Medial Pontine Area: A Safe Entry to the Brainstem as a Cut Above the Rest.

To examine the fiber-based anatomy of the medial pontine area (MPA), one of the most commonly used brainstem (BS) safe entry zones in neurosurgery. According to the protocol of Klingler and Ludwig, six BSs were kept in 10% formalin solution for at least 2 months. After removing the arachnoid mater, pia mater, and vascular structures, the samples were frozen at -16°C for at least 2 weeks. White matter (WM) pathways of the BS were gradually examined using fiber dissections under a surgical microscope. Safe entry zones of the BS were defined and investigated, focusing on the ventral pontine region and pontomesencephalic junction. Because of the lack of fibers on the anterior surface of the pons, the MPA formed a safe surgical area. The MPA, strategically positioned between the descending corticospinal tracts and extending securely to the anterior limit of the medial lemniscus, serves as a protective pathway, creating a secure environment for accessing safe entry zones within the BS during surgery. The position of the MPA has the potential to provide a combined surgical path with superiorly located BS entry zones, resulting in a larger surgical area. Entry to the BS via the MPA increases the accessible surface area in the ventral pons and can be combined with the other perioculomotor safe regions outlined. Our findings might lead to safer endoscopic endonasal transclival interventions for intrinsic pontine lesions.

Comparison of the Retrosigmoid Suprameatal and Anterior Subtemporal Transpetrosal Approaches After Full Exposure of the Internal Acoustic Meatus.

Surgical approaches to the ventral brainstem and petroclival regions are complex, and standard retrosigmoid and subtemporal approaches are often inadequate. Retrosigmoid suprameatal tubercle (RSMTA) and anterior subtemporal transpetrosal (ASTA) approaches may provide extended surgical exposure with less brain retraction. The objective of this study was to evaluate advantages and disadvantages of RSMTA vs ASTA, and illustrate the surgical corridors and 3-dimensional microsurgical anatomy of the related structures. Four silicone-injected adult cadaver heads (8 sides) were dissected to evaluate the accessibility of lesions located at the petrous apex, ventral brainstem, and pontomedullary region using ASTA and RSTMA. Both ASTA and RSMTA provide access from the petrous apex to the ventral lower pons and pontomedullary junction. A greater extent of safely resected bone was found in ASTA vs RSMTA. ASTA provides a larger surgical view to the ventrolateral midpons, peritrigeminal region, superior neurovascular complex, pontomesencephalic junction, and posterior cavernous sinus. Meanwhile, through cranial nerve V mobilization, RSMTA provides a larger surgical view to the lower half part of the pons, ventrolateral part of the pontomedullary junction, and middle and lower neurovascular structures. The choice of surgical approach is determined by considering the area where the lesion originates, lesion size, the anatomic structures to which it extends, and evaluation of the area that can be surgically exposed. Our study highlights the differences between these approaches and important surgical anatomic considerations.

Oculomotor nerve segment between proximal posterior and superior cerebellar arteries: an MRI study.

No study has documented the oculomotor nerve (OMN) segment lying between the posterior cerebral (PCA) and superior cerebellar (SCA) arteries adjacent to the brainstem. The present study aimed to characterize it. A total of 71 patients underwent thin-sliced, sagittal T2-weighted magnetic resonance imaging for analysis. The OMN segments lying between the PCA and SCA were identified in all patients. The OMN segment in relation to the PCA and SCA was classified into five types. Of them, the PCA-OMN contact type was the most frequent and found in 35.2% of 71 sides on the right and 39.4% on the left. Also, the PCA-OMN compression type was identified in 12.7% on the right and 15.5% on the left. In these types, the mean distance between the brainstem and contact/compression sites were measured 4.4 ± 2.3mm on the right and 4.4 ± 1.6mm on the left. In more than forty percent, the sites were located at the level of the pontomesencephalic junction. The OMN may be frequently in contact with the PCA near the brainstem. The site located more distal than the central-peripheral myelin junction of the OMN can attribute to a low frequency of neurovascular compression syndrome of the nerve.

Radiological anatomy of the vertebrobasilar artery in a select South African population

IntroductionThe vertebrobasilar artery is the combination of the bilateral vertebral artery and the basilar artery. The basilar artery extends from the confluence of the bilateral vertebral arteries at the pontomedullary junction, terminating at the ponto-mesencephalic junction. Depending on the geometry of the intracranial vertebral arteries and the incidence of arterial tortuosity, the basilar artery may exhibit variable course patterns. This morphologic deformation has negative implications on the hemodynamic of blood flow in the posterior circulatory territory by inducing the development of infarcts and thus increasing the risk of vascular pathologies. Lateral displacement of the basilar artery has been associated with migraines and frequent headaches. The present study aimed to investigate the radiological anatomy of the basilar artery within a select South African cohort of patients in terms of the course patterns and morphometry. Materials and methodThe study is an observational retrospective chart review of 100 radiographic images (Average age: 59; Males: 60%; Females: 40%) of multidetector computed tomography angiography, of the vertebrobasilar artery to establish the course pattern of the basilar artery. ResultsAsymmetry of the intracranial vertebral artery as well as lateral displacement of the basilar artery have been reported with varying course patterns. The average length and diameter of the basilar artery were reported as 25.41 ± 6.44 mm 2.72 ± 0.85 mm, respectively. ConclusionThe geometric characteristics of the vertebrobasilar system in the population studied can predispose to some cerebrovascular diseases in the posterior circulatory territory and influence the build-up of atherosclerotic plaque. Knowledge of this variant anatomy is imperative to the clinician in the diagnosis of many vascular-related pathologies.

Unilateral Internuclear Ophthalmoplegia Following Minor Head Injury

A lesion in the medial longitudinal fasciculus (MLF) causes internuclear ophthalmoplegia (INO). Many intracranial lesions, such as multiple sclerosis or vascular disorders may be associated with INO; however, INO is a rare complication of minor head injury. The mechanism underlying injury to the MLF may be shear force on the brain stem during head trauma. The shear force can tear or stretch the fibers of the MLF and can also lead to compromise or rupture of the perforating branches of the basilar artery. We present an unusual case of unilateral INO after minor head injury in a patient with a small site of hemorrhage in the midline of the pontomesencephalic junction, confirmed by brain magnetic resonance imaging using susceptibility-weighted imaging.

How I do it: surgical resection of ventrolateral pontomesencephalic junction glioma via oculomotor-tentorial triangle.

The surgical resection of the pontomesencephalic junction (PMJ) glioma is difficult because the access is challenging due to nearby complicated neurovascular structures. We report a left ventrolateral PMJ glioma successfully resected via the oculomotor-tentorial triangle (OTT), with improved right extremity weakness postoperatively while preserving the pyramidal tract, which resided laterally and posteriorly to the lesion. This case demonstrates the value of the OTT in brainstem surgery.

A Topographic Atlas of the Human Brainstem in the Ponto-Mesencephalic Junction Plane.

The human brainstem harbors neuronal aggregates that ensure the maintenance of several vital functions. It also acts as a major relay structure for the neuronal information that travels between the cerebral cortex, the cerebellum and the spinal cord. As such, this relatively small portion of the human brain houses a multitude of ascending and descending fibers that course among numerous nuclei whose exact boundaries are still uncertain. Such a large number of nuclei and fiber tracts confined to a relatively small and compact brain region imposes upon the brainstem a highly complex cytoarchitectonic organization that still needs to be deciphered. The present work provides a topographic atlas of the human brainstem composed of 45 anatomical plates, each containing a pair of adjacent sections stained with Cresyl Violet and Luxol Fast Blue to help delineating brainstem nuclei and fiber tracts, respectively. The plates, which cover the entire midbrain, pons and medulla oblongata, are composed of equally-spaced sections referenced and aligned parallel to the ponto-mesencephalic junction rather than the fastigium or the obex. This topographic landmark is particularly suitable for neurosurgical interventions aiming at specific nuclei of the mesencephalic tegmentum. In complement, we provide 8 anatomical plates containing adjacent sections stained for choline acetyltransferase and Luxol Fast Blue, taken through the midbrain and the pons. This open access atlas of the human brainstem is intended to assist neuroanatomists, neurosurgeons and neuropathologists in their work.

Joubert syndrome: incidence and clinicoradiological description of a genotyped series of seven cases

Joubert syndrome is produced by an alteration of the ciliary proteins essential for the structure and function of neurons and organs such as the kidneys, liver, sight, and hearing. Some 34 mutations are currently known. Calculate the incidence / prevalence, describe the phenotype / genotype and radiological alterations of this ciliopathy in our health area. We reviewed the medical records with a diagnosis of Joubert Syndrome in the last 10 years to collect phenotype, radiological characteristics, and extra-neurological manifestations in relation to the genetic alteration detected. 7 cases were included: 5 children (6 -17 years). They had 6 different mutations. Hypotonia, thin / long fingers and delayed psychomotor development were constant. They presented dysmorphic features, mental retardation, ocular apraxia, and nystagmus indistinctly in 3/7; Neonatal apnea/hyperpnea 2/7; hypoplasia of vermis 7/7; Molar syndrome was evident in 6/7 and in 2/7 there was elongation-thinning of cerebellar peduncles. Pontomesencephalic junction tightness 6/7; fastigium of the IV ventricle high in 4/7. Among the somatic complications, retinopathy 2/7, retinal coloboma 1/7, liver fibrosis 1/7, nephronoptysis 1/7 and renal cyst 1/7. The incidence of Joubert syndrome was at least 1 / 20,000 newborns / year. The pontomesencephalic and peduncular radiological alterations were constant. Hypotonia, psychomotor retardation, and thin / long fingers affected all cases.

Human basilar artery: morphology & variations

<sec> Introduction Basilar artery is an unpaired medium-sized artery formed by the confluence of right and left vertebral arteries at the pontomedullary junction and extends to the pontomesencephalic junction. It forms the spine of posterior cerebral circulation which is constituted by the vertebrobasilar system and its branches. Normal morphology of the basilar artery forms an essential component of cerebral circulation. The present study aims to measure the level of formation &amp; termination, length, diameter, and angle of formation of the basilar artery. The data presented are relevant to understanding human variations and would be a good anatomical reference for clinicians, anatomists, and medical students. Caliber, length, and angle of bifurcation of the basilar artery help in assessing the feasibility and approach for various surgical procedures and predict cerebro-vascular diseases. </sec><sec> Materials &amp; methods 96 adult human brain specimens were studied. (78 male, 18 female) (Age range: 19–80 y; Average age: 47.66 y). Measurements were taken using Vernier calliper. Data was analysed using Microsoft Excel and SPSS software version 17. </sec><sec> Results The basilar artery was formed by the confluence of two vertebral arteries in all specimens extending from the pontomedullary junction to the pontomesencephalic junction in 2/3^rd of the cases. The left vertebral artery was found to be dominant in 62.5% specimens. The basilar artery showed an average length of 3.1 cm (demonstrating positive correlation with age), average diameter of 3.6–3.9 mm at different levels, and average angle of formation as 65.38° in males and 62.22° in females. Fetal type posterior cerebral artery was noticed in 9.4% cases. 3.1% and 6.3% cases were seen on the right and left sides respectively. Basilar artery fenestration was noted in 2 percent specimens. </sec><sec> Conclusion Basilar artery morphology was studied in 96 human adult cadavers. Basilar artery formation and termination was normal in more than 2/3^rd cases. Variations were noted in its origin, vessel hypoplasia, presence of fenestrations, and fetal patterns. The data obtained from this study are relevant for anatomists, medical students, interventional radiologists, and neurosurgeons. </sec>

Physiological properties of the lamina I spinoparabrachial neurons in the mouse.

Spinal cord lamina I neurons receiving dense input from nociceptors and projecting to the parabrachial area at the ponto-mesencephalic junction form the major ascending pain-related pathway in rodents. Lamina I spinoparabrachial (SPB) neurons have never been characterized in mice, despite the growing and extensive use of this species to understand the contribution of lamina I SPB neurons in chronic pain. The electrophysiological properties of lamina I SPB neurons recorded here in anaesthetized mice are comparable to those of rat or cat, forming a nociceptive and thermoreceptive pathway. It was confirmed 'on line' that lamina I SPB neurons that normally encode noxious stimuli can receive input from low threshold mechanoreceptors in certain conditions. The present work indicates that the study of lamina I SPB neurons in vivo could take advantage of the use of genetically modified mice. Ongoing studies investigating the role of lamina I projection neurons in the generation of chronic pain are mainly based on the use of genetically modified mice. However, lamina I projection neurons have never been physiologically characterized in this species. The present work aimed to fill this gap, and to assess the effect of spinal 'disinhibition' that may occur in chronic pain states on the responses of these neurons to light touch. Seventy lamina I spinoparabrachial (SPB) neurons were characterized in anaesthetized mice. These neurons showed low central conduction velocities (<12.4ms-1 ) and wide range of responses. Fifty-six neurons responded equally to noxious mechanical and thermal (heat) stimuli (16% responded consistently to light touch). Modality-specific neurons responded preferentially to thermal (cold) stimuli (n=10) and pinch (n=2), or specifically to heat (n=2). Spinal bicuculline and strychnine application induced responses to brush in half of the neurons tested, confirming directly the potential connection between low threshold mechanoreceptors and nociceptive-specific neurons, responsible for mechanical allodynia. Remarkably, the effect of the treatment was highly variable and apparently independent of the initial profile of the neurons. The present data confirm that mice lamina I SPB neurons have the expected characteristics to form a nociceptive and thermoreceptive pathway, but they constitute a highly heterogeneous group. The differential effect of spinal disinhibition observed here suggests that a subgroup of lamina I SPB neurons might be responsible for abnormal pain in pathological conditions, and emphasizes the importance of in vivo recording, a neglected approach.

Case 266.

History A 1-year-old boy was referred for cochlear implant assessment after he received a diagnosis of bilateral profound sensorineural hearing loss at neonatal hearing screening shortly after birth. The child was born at term via uneventful delivery, and there was no history of familial hearing loss or maternal illness. Tympanic membranes were normal, and hearing loss was confirmed with auditory brainstem testing, which showed no response from either ear. Hearing aids were provided from 3 months of age, but no behavioral responses were noted when these were worn. He was also noted to have some mild developmental delay throughout his 1st year of life and was slow to crawl, roll over, and stand up. Physical examination showed no syndromic features or physical abnormalities. Ophthalmology confirmed normal vision and visual movements but bilateral anesthetic corneas. He had corneal abrasions due to minor repeated corneal trauma, and left-sided tarsorraphy was performed at 6 months. Facial nerve function, swallow, and voice quality were normal. To assess suitability for a cochlear implant, the patient underwent MRI of the temporal lobe and brain ( Figs 1 - 4 ) and thin-section CT of the temporal bones ( Figs 5 , 6 ). The patient subsequently underwent left cochlear implantation. Figure 1: Sagittal midline T1-weighted 1.5-T MR image (repetition time msec/echo time msec, 541/15). Figure 2: Axial T2-weighted MR image (6703/116, 4-mm section thickness) at the level of the pontomesencephalic junction. Figure 3: Axial T2-weighted MR image one level inferior to that shown in Figure 2 . Figure 4a: (a) Axial 1.5-T single-slab three-dimensional (3D) turbo spin-echo MR image (1200/271) at the level of the right internal auditory canal. (b) Corresponding axial 1.5-T single-slab 3D turbo spin-echo MR image at the level of the left internal auditory canal. Figure 4b: (a) Axial 1.5-T single-slab three-dimensional (3D) turbo spin-echo MR image (1200/271) at the level of the right internal auditory canal. (b) Corresponding axial 1.5-T single-slab 3D turbo spin-echo MR image at the level of the left internal auditory canal. Figure 5: Unenhanced axial thin-section (0.7-mm section thickness) CT image of the temporal bone at the level of the internal auditory canals and middle cochlear turns. Figure 6: Unenhanced axial thin-section (0.7-mm section thickness) CT image of the temporal bone at a level slightly inferior to that shown in Figure 5 .

Morphometric Study of Basilar Artery in the Eastern Indian Population.

Introduction:The basilar artery (BA) is formed by the fusion of right and left vertebral arteries and divides to form right and left posterior cerebral arteries. This study was done to provide a baseline database regarding length, mid-length diameter, level of origin, and level of termination of BA.Materials and Methods:Thirty-eight formalin-fixed brains were obtained from cadavers dissected for undergraduate studies. The external length and the average external diameter of BA were measured by a digital Vernier caliper. Variation in origin and termination of BA was noted using magnifying glass.Results:The length and diameter of the BA were 25.58 ± 3.57 mm and 3.05 ± 0.41 mm, respectively. The origin and termination of BA was normal in most cases. In two cases, the origin was above the pontomedullary junction, and in one case, it was below. In two cases, the termination was above the pontomesencephalic junction, and in one case, it was below.Conclusion:There was no gender predisposition in length and diameter of the basilar artery. The baseline data established in this study regarding length, diameter, level of origin and level of termination of basilar artery will help neurosurgeons and interventional radiologists to diagnose as well as plan and execute various vascular procedures such as shunting for the treatment of aneurysms and stenosis in the blood vessels of the posterior cranial fossa.

The oculomotor-tentorial triangle. Part 2: a microsurgical workspace for vascular lesions in the crural and ambient cisterns.

Pathology in the region of the basilar quadrifurcation, anterolateral midbrain, medial tentorium, and interpeduncular and ambient cisterns may be accessed anteriorly via an orbitozygomatic (OZ) craniotomy. In Part 1 of this series, the authors explored the anatomy of the oculomotor-tentorial triangle (OTT). In Part 2, the versatility of the OTT as a surgical workspace for treating vascular pathology is demonstrated. Sixty patients with 61 vascular pathologies treated within or via the OTT from 1998 to 2017 by the senior author were retrospectively reviewed. Patients were grouped together based on pathology/surgical procedure and included 1) aneurysms (n = 19); 2) posterior cerebral artery (PCA)/superior cerebellar artery (SCA) bypasses (n = 24); 3) brainstem cavernous malformations (CMs; n = 14); and 4) tentorial region dural arteriovenous fistulas (dAVFs; n = 4). The majority of patients were approached via an OZ craniotomy, wide sylvian fissure split, and temporal lobe mobilization to widen the OTT. Aneurysm locations included the P1-P2 junction (n = 7), P2A segment (n = 9), P2/3 (n = 2), and basilar quadrification (n = 1). Aneurysm treatments included clip reconstruction (n = 12), wrapping (n = 3), proximal occlusion (n = 2), and trapping with (n = 1) or without (n = 1) bypass. Pathologies in the bypass group included vertebrobasilar insufficiency (VBI; n = 3) and aneurysms of the basilar trunk (n = 13), basilar apex (n = 4), P1 PCA (n = 2), and s1 SCA (n = 2). Bypasses included M2 middle cerebral artery (MCA)-radial artery graft (RAG)-P2 PCA (n = 8), M2 MCA-saphenous vein graft (SVG)-P2 PCA (n = 3), superficial temporal artery (STA)-P2 PCA (n = 5) or STA-s1 SCA (n = 3), s1 SCA-P2 PCA (n = 1), V3 vertebral artery (VA)-RAG-s1 SCA (n = 1), V3 VA-SVG-P2 PCA (n = 1), anterior temporal artery-s1 SCA (n = 1), and external carotid artery (ECA)-SVG-s1 SCA (n = 1). CMs were located in the midbrain (n = 10) or pontomesencephalic junction (n = 4). dAVFs drained into the tentorial, superior petrosal, cavernous, and sphenobasal sinuses. High rates of aneurysm occlusion (79%), bypass patency (100%), complete CM resection (86%), and dAVF obliteration (100%) were obtained. The overall rate of permanent oculomotor nerve palsy was 8.3%. The majority of patients in the aneurysm (94%), CM (93%), and dAVF (100%) groups had stable or improved modified Rankin Scale scores. The OTT is an important anatomical triangle and surgical workspace for vascular lesions in and around the crural and ambient cisterns. The OTT can be used to approach a wide variety of vascular pathologies in the region of the basilar quadrifurcation and anterolateral midbrain.

Cranial Cavernous Malformations: Natural History and Treatment.

Cavernous malformations (CMs), also known as cavernous angiomas or cavernomas, are low-flow vascular malformations of the brain and spinal cord that consist of clusters of dilated sinusoidal channels lined with endothelial cells that do not exhibit intervening tight junctions. The involved blood vessels lack muscular and elastic layers, and blood at various stages of thrombosis and organization often fills the thin-walled vascular caverns. CMs are grossly distinct from adjacent brain and have a lobulated appearance sometimes likened to a mulberry, with a characteristic dark red or purple color. Hemosiderin and gliosis often surround CMs of the brain and spinal cord; no neural tissue is present inside the lesion. Except for developmental venous anomalies (DVAs) present in ≈33% of CMs,1 no abnormal vascularity is typically seen on digital subtraction angiography, leading CMs to be termed cryptic or occult vascular malformations (Figure 1). Multiple small hemorrhage events lead to a pathognomonic popcorn appearance on magnetic resonance (MR) imaging because of hemosiderin staining from blood products of various ages. Calcifications may be present on computed tomographic imaging (Figure 2). Figure 1. A 48-year-old woman presented with headaches. A , Magnetic resonance imaging of the brain with T2-weighted imaging demonstrated a 1.1-cm lesion in the cerebellar vermis with mixed signal intensity. B – D , Susceptibility-weighted imaging demonstrated hemosiderin within the lesion’s core and a developmental venous anomaly associated with the cavernous malformation (arrowheads). Figure 2. A 28-year-old woman presented with partial seizures without secondary generalization. A , Noncontrast computed tomography of the head demonstrated a 1.4-cm right posterior cingulate hyperdensity, with evidence of mild hemorrhage and calcification. Magnetic resonance imaging of the brain demonstrated the cavernous malformation to have a core of mixed signal intensity, heterogeneous enhancement, and a rim of hemosiderin consistent with a cavernous malformation, as evidenced on ( B ) susceptibility-weighted imaging, ( C ) T2-weighted …

Internuclear ophthalmoplegia plus ataxia indicates a dorsomedial tegmental lesion at the pontomesencephalic junction.

Internuclear ophthalmoplegia (INO) indicates a lesion involving the medial longitudinal fasciculus (MLF) that interconnects the abducens nucleus and medial rectus subnucleus of the oculomotor nuclear complex. In fact, rostral-caudal localization value of the INO is often limited except when it accompanies symptoms and signs owing to involvement of nearby structures. Ataxia is often observed in lesions involving the cerebellum or the fibers to and from it anywhere in the brainstem. Herein, we sought to determine the localizing value of INO plus ataxia in the rostrocaudal axis of the brainstem. Thirty patients with INO plus limb or truncal ataxia were subjected to analyses. For comparison, 20 patients with isolated INO without any ataxia served as the control. We determined the lesion extent in the MRIs responsible for INO plus ataxia using a probabilistic lesion mapping and subtraction analysis and analyzed the neuro-otologic findings using video-oculography. In patients with INO with limb or truncal ataxia, the responsible lesions were mostly restricted to the paramedian tegmentum at the pontomesencephalic junction. In contrast, the lesions causing isolated INO without ataxia were mostly located in the caudal or mid-pontine area. The rostro-caudal distribution of the lesions was similar among the patients with only limb ataxia (n=3), both limb and truncal ataxia (n=10), and only truncal ataxia (n=17). INO plus ataxia indicates a lesion involving the MLF at the pontomesencephalic junction. Damage to the brachium conjunctivum or mesencephalic locomotor region may explain the ataxia in association with INO in lesions involving this area.

Distribution of catecholaminergic presympathetic-premotor neurons in the rat lower brainstem

We previously characterized the organization of presympathetic-premotor neurons (PSPMNs), which send descending poly-synaptic projections with collaterals to skeletal muscle and the adrenal gland. Such neurons may play a role in shaping integrated adaptive responses, and many of them were found within well-characterized regions of noradrenergic cell populations suggesting that some of the PSPMNs are catecholaminergic. To address this issue, we used retrograde trans-synaptic tract-tracing with attenuated pseudorabies virus (PRV) recombinants combined with multi-label immunofluorescence to identify PSPMNs expressing tyrosine hydroxylase (TH). Our findings indicate that TH-immunoreactive (ir) PSPMNs are present throughout the brainstem within multiple cell populations, including the A1, C1, C2, C3, A5 and A7 cell groups along with the locus coeruleus (LC) and the nucleus subcoeruleus (SubC). The largest numbers of TH-ir PSPMNs were located within the LC and SubC. Within SubC and the A7 cell group, about 70% of TH-ir neurons were PSPMNs, which was a significantly greater fraction of neurons than in the other brain regions we examined. These findings indicate that TH-ir neurons near the pontomesencephalic junction that are distributed across the LC, SubC, and the A7 may play a prominent role in somatomotor–sympathetic integration, and that the major functional role of the A7 and SubC noradrenergic cell groups maybe in the coordination of concomitant activation of somatomotor and sympathetic outflows. These neurons may participate in mediating homeostatic adaptations that require simultaneous activation of sympathetic and somatomotor nerves in the periphery.

Morphometry of basilar artery in population of Gujarat

IntroductionThe basilar artery is a large median vessel responsible for supplying various parts of the brain. The aim of this study was to observe, record and compare variations in basilar artery regarding its length, mid length diameter, level of origin and level of termination. MethodSixty human formalin fixed brain specimens obtained from cadavers donated for the study purpose were under examination in the Dept. of Anatomy, Gov. Medical College, Baroda. The process was undertaken according to the dissection method as per the Cunningham manual. The variation in length and diameter of basilar artery was noted using Digital Vernier calipers. Variation in origin and termination of basilar artery was noted using magnifying glass. ResultsVariation in basilar artery diameter found ranged from min 2.02 mm to max 4.45 mm. Variation in length found ranged from min 20.1 mm to 42.02. In most of the cases basilar artery origin and termination was normal. In 4 cases origin was above the Ponto-Medullary junction and in 3 cases it was below. In 2 cases termination was above the Ponto-Mesencephalic junction and in 1 case it was below. DiscussionThis observation highlight the variations in morphological aspects of the basilar artery, the knowledge of variations would help neurosurgeons safely diagnose, as well as plan and execute vascular bypass and shunting procedures for the treatment of stenosis, aneurysms and arteriovenous malformations in the posterior cranial fossa.

Quantitative study of white matter neurons in human temporal lobe resection with mild malformation of cortical development (MCD) type II

Quantitative study of white matter neurons in human temporal lobe resection with mild malformation of cortical development (MCD) type II

P12.13 * SURGICAL TREATMENT OF BRAINSTEM TUMORS

OBJECTIVE: To determine the extent of resection and neurological outcomes after surgical treatment of brainstem tumors. METHODS: 34 patients with brainstem tumors operated in Regional Centre of Neurosurgery and Neurology from January, 2008 till January, 2014 were retrospectively analyzed. 20 (58.8%) patients were male, and 14 (41.2%) – female. Mean age of the patients was 22.7 years. Among them 16 (47.1%) were of pediatric age, 18 (52.9%) – adults. In 20 cases (58.8%) tumor had exophytic growth pattern into fourth ventricle. In purely intrinsic tumors (14 cases, 41.2%) the localization was: midbrain – 5 patients (14.7%), ponto-mesencephalic junction – 2 cases (5.9%), pons – 2 patients (5.9%), ponto-medullary junction – 2 cases (5.9 %), medulla oblongata – 3 patients (8.8%). Patients were examined neurologically on admission and one month after surgery. The extent of tumor resection was evaluated on early postoperative MRI (first 48 hours). RESULTS: Surgical approach was chosen individually in each case according to tumor location, using a 2-point method. In patients with midbrain tumors 3 different approaches were used: subtemporal (2 cases, 5.9%), occipital transtentorial (2 cases, 5.9%) and supracerebellar (1 patient, 2.9%). In 2 patients (5.9%) retrosigmoid approach was used. The “workhorse” approach in our series was median suboccipital with telo-velar entrance into the cavity of IV ventricle, which was used in 27 cases (79.4%). The tumors were resected through “safe entry” zones in the brainstem. In 28 cases (82.4%) gross total resection was achieved, in 6 patients (17.6%) the resection was subtotal (>90%). 5 patients (14.7%) deteriorated neurologically after surgery on 30 day follow-up, 29 patients (85.3%) improved or remained stable. None of the operated patients died. Histologic results: anaplastic ependymoma – 9 patients (26.5%), ependymoma – 5 patients (14.7%), pilocityc astrocytoma – 6 patients (17.6%), anaplastic astrocytoma – 4 patients (11.8%), medulloblastoma with significant brainstem invasion – 4 patients (11.8%), choroid plexus papilloma – 2 patients (5.9%), metastasis – 2 patients (5.9%), germinoma – 1 patient (2.9%), dermoid – 1 patient (2.9%). CONCLUSION: Surgical treatment of brainstem tumors can be done effectively (gross total removal in 82.4%) and relatively safe (morbidity – 14.7%, mortality – 0%).

Successful excision of a pontomesencephalic cavernoma through anterior subtemporal route without mapping: Anatomical landmarks as a road map

Successful excision of a pontomesencephalic cavernoma through anterior subtemporal route without mapping: Anatomical landmarks as a road map