Chronic hyperglycemia and intracranial meningiomas

Meningiomas are among the most common primary tumors of the central nervous system. Previous research into the meningioma histological appearance, genetic markers, transcriptome and epigenetic landscape has revealed that benign meningiomas significantly differ in their glucose metabolism compared to aggressive lesions. However, a correlation between the systemic glucose metabolism and the metabolism of the tumor hasn't yet been found. We hypothesized that chronic levels of glycaemia (approximated with glycated hemoglobin (HbA1c)) are different in patients with aggressive and benign meningiomas. The study encompassed 71 patients with de novo intracranial meningiomas, operated on in three European hospitals, two in Croatia and one in Spain. Our results show that patients with WHO grade 2 meningiomas had significantly higher HbA1c values compared to patients with grade 1 lesions (P = 0.0290). We also found a significant number of patients (19/71; 26.7%) being hyperglycemic, harboring all the risks that such a condition entails. Finally, we found a significant correlation between our patients' age and their preoperative HbA1c levels (P = 0.0008, ρ(rho) = 0.388), suggesting that older meningioma patients are at a higher risk of having their glycaemia severely dysregulated. These findings are especially important considering the current routine and wide-spread use of corticosteroids as anti-edematous treatment. Further research in this area could lead to better understanding of meningiomas and have immediate clinical impact.

Decreased brain volume may be associated with the occurrence of peri-lead edema in Parkinson's disease patients with deep brain stimulation

BACKGROUND

Peri-lead edema (PLE) is a poorly understood complication of deep brain stimulation (DBS), which has been described in patients presenting occasionally with profound and often delayed symptoms with an incidence ranging from 0.4% up to even 100%. Therefore, our study aims to investigate the association of brain and brain compartment volumes on magnetic resonance imaging (MRI) with the occurrence of PLE in Parkinson's disease (PD) patients after DBS implantation in subthalamic nuclei (STN).

METHODS

This retrospective study included 125 consecutive PD patients who underwent STN DBS at the Department of Neurosurgery, Dubrava University Hospital from 2010 to 2022. Qualitative analysis was done on postoperative MRI T2-weighted sequence by two independent observers, marking PLE on midbrain, thalamus, and subcortical levels as mild, moderate, or severe. Quantitative volumetric analysis of brain and brain compartment volumes was conducted using an automated CIVET processing pipeline on preoperative MRI T1 MPRAGE sequences. In addition, observed PLE on individual hemispheres was delineated manually and measured using Analyze 14.0 software.

RESULTS

In our cohort, PLE was observed in 32.17%, mostly bilaterally. Mild PLE was observed in the majority of patients, regardless of the level observed. Age, sex, diabetes, hypertension, vascular disease, and the use of anticoagulant/antiplatelet therapy showed no significant association with the occurrence of PLE. Total grey matter volume showed a significant association with the PLE occurrence (r = -0.22, p = 0.04), as well as cortex volume (r = -0.32, p = 0.0005). Cortical volumes of hemispheres, overall hemisphere volumes, as well as hemisphere/total intracranial volume ratio showed significant association with the PLE occurrence. Furthermore, the volume of the cortex and total grey volume represent moderate indicators, while hemisphere volumes, cortical volumes of hemispheres, and hemisphere/total intracranial volume ratio represent mild to moderate indicators of possible PLE occurrence.

CONCLUSION

The results of our study suggest that the morphometric MRI measurements, as a useful tool, can provide relevant information about the structural status of the brain in patients with PD and represent moderate indicators of possible PLE occurrence. Identifying patients with greater brain atrophy, especially regarding grey matter before DBS implantation, will allow us to estimate the possible postoperative symptoms and intervene in a timely manner. Further studies are needed to confirm our findings and to investigate other potential predictors and risk factors of PLE occurrence.

Bilateral posterior fossa chronic subdural hematoma as a cause of hydrocephalus

Background

Infratentorial chronic subdural hematoma (cSDH) is still a rather elusive neurosurgical entity, which, due to its proximity and likely compression of the cerebellum and brainstem, can lead to devastating consequences. To establish standardized treatment, more studies and reports regarding its therapy are needed. We report a case of a simultaneous unilateral supratentorial and bilateral infratentorial cSDH, with the latter causing hydrocephalus and successfully treated with a bilateral burr-hole trepanation of occipital bone and placement of subdural drains.

Case Description

A 71-year-old man with gait disturbance, Glasgow Coma Scale 12, and a radiologically verified unilateral supratentorial and bilateral cSDH of the posterior fossa causing cerebellum, brainstem, and fourth ventricle compression with obstructive hydrocephalus, underwent surgical evacuation of infratentorial hematoma with a bilateral burr-hole trepanation. The postoperative course was uneventful, with a control head computed tomography scan showing the resolution of the hematoma and hydrocephalus. The patient was discharged with no newly acquired neurological deficits.

Conclusion

Due to a limited number of reports and studies involving infratentorial cSDHs causing hydrocephalus, decision-making and optimal surgical treatment remain unclear. We recommend a timely surgical evacuation of the hematoma if the patient is symptomatic while avoiding placement of external ventricular drainage.

Deep brain stimulation in disorders of consciousness: 10 years of a single center experience

Disorders of consciousness (DoC), namely unresponsive wakefulness syndrome (UWS) and minimally conscious state (MCS), represent severe conditions with significant consequences for patients and their families. Several studies have reported the regaining of consciousness in such patients using deep brain stimulation (DBS) of subcortical structures or brainstem nuclei. Our study aims to present the 10 years' experience of a single center using DBS as a therapy on a cohort of patients with DoC. Eighty Three consecutive patients were evaluated between 2011 and 2022; entry criteria consisted of neurophysiological and neurological evaluations and neuroimaging examinations. Out of 83, 36 patients were considered candidates for DBS implantation, and 32 patients were implanted: 27 patients had UWS, and five had MCS. The stimulation target was the centromedian-parafascicular complex in the left hemisphere in hypoxic brain lesion or the one better preserved in patients with traumatic brain injury. The level of consciousness was improved in seven patients. Three out of five MCS patients emerged to full awareness, with the ability to interact and communicate. Two of them can live largely independently. Four out of 27 UWS patients showed consciousness improvement with two patients emerging to full awareness, and the other two reaching MCS. In patients with DoC lasting longer than 12 months following traumatic brain injury or 6 months following anoxic-ischemic brain lesion, spontaneous recovery is rare. Thus, DBS of certain thalamic nuclei could be recommended as a treatment option for patients who meet neurological, neurophysiological and neuroimaging criteria, especially in earlier phases, before occurrence of irreversible musculoskeletal changes. Furthermore, we emphasize the importance of cooperation between centers worldwide in studies on the potentials of DBS in treating patients with DoC.

Predictive value of spinal CSF volume in the preoperative assessment of patients with idiopathic normal-pressure hydrocephalus

Introduction

The pathophysiology, diagnosis, and management of idiopathic normal pressure hydrocephalus (iNPH) remain unclear. Although some prognostic tests recommended in iNPH guidelines should have high sensitivity and high predictive value, there is often no positive clinical response to surgical treatment.

Materials and methods

In our study, 19 patients with clinical and neuroradiological signs of iNPH were selected for preoperative evaluation and possible further surgical treatment according to the guidelines. MR volumetry of the intracranial and spinal space was performed. Patients were exposed to prolonged external lumbar drainage in excess of 10 ml per hour during 3 days. Clinical response to lumbar drainage was assessed by a walk test and a mini-mental test.

Results

Twelve of 19 patients showed a positive clinical response and underwent a shunting procedure. Volumetric values of intracranial space content in responders and non-responders showed no statistically significant difference. Total CSF volume (sum of cranial and spinal CSF volumes) was higher than previously published. No correlation was found between spinal canal length, CSF pressure, and CSF spinal volume. The results show that there is a significantly higher CSF volume in the spinal space in the responder group (n = 12) (120.5 ± 14.9 ml) compared with the non-responder group (103.1 ± 27.4 ml; n = 7).

Discussion

This study demonstrates for the first time that CSF volume in the spinal space may have predictive value in the preoperative assessment of iNPH patients. The results suggest that patients with increased spinal CSF volume have decreased compliance. Additional prospective randomized clinical trials are needed to confirm our results.

METEOROLOGICAL VARIABLES ASSOCIATED WITH SUBARACHNOID HEMORRHAGE: A SINGLE CENTER STUDY

Spontaneous subarachnoid hemorrhage (SAH) can occur unexpectedly and independently of the classic risk factors. Several different factors could affect intracranial aneurysm (IA) rupture, such as morphological and hemodynamic factors. The aim of this study was to establish the potential association of meteorological data such as temperature, atmospheric pressure, and humidity, and the onset of clinical symptoms preceding hospital admission of patients with acute SAH due to IA rupture. This retrospective study included 130 consecutive patients admitted for non-traumatic SAH with a determinable onset of SAH symptoms. The effects of meteorological parameters of atmospheric pressure, ambient temperature, and relative air humidity on the day of acute SAH onset and 24 hours prior to the onset of symptoms were recorded and analyzed in each patient. Spearman rank correlation analysis was used to assess the risks of incident SAH on the basis of daily meteorological data. Seasonal incidence of acute SAH showed the peak incidence in winter and a trough in summer, with monthly incidence peak in January and December. The circadian rhythm analysis showed the peak incidence of SAH in the forenoon, followed by the evening. Acute SAH incidence showed moderate positive association with daily atmospheric pressure (p<0.05), while no association was found with ambient temperature and relative air humidity. Our results suggested no significant association of changes in ambient temperature and relative humidity with the risk of SAH. Increases in atmospheric pressure were weakly associated with a higher SAH risk. Additional studies are needed to establish in detail both meteorological and morphological factors important to predict IA rupture and SAH.

TRANSVENOUS APPROACH FOR INDIRECT CAROTID-CAVERNOUS FISTULA USING DETACHABLE COILS: A CASE REPORT AND REVIEW OF TREATMENT OPTIONS

Carotid-cavernous fistula (CCF) is a relatively rare pathology with a low incidence compared with other vascular pathologies. They can be classified based on hemodynamics as low- or high-flow fistulas, and anatomically as direct or indirect fistulas. Anatomy of the shunt somewhat dictates the selection of endovascular treatment, meaning the venous or arterial approach and selection of embolizing materials. Although there is general agreement as to when to access CCF transvenously or transarterialy, which depends on the shunt being direct or indirect, there is no uniform agreement on which occlusion method should be used. Herein, we report a case of an 80-year-old woman treated for indirect CCF using detachable coils. We also provide a brief review of the literature, including recent advances in treatment of said entities. In conclusion, selection of both the approach and material used depends on the operator's experience and preference.

Cerebrospinal fluid micro-volume changes inside the spinal space affect intracranial pressure in different body positions of animals and phantom

Interpersonal differences can be observed in the human cerebrospinal fluid pressure (CSFP) in the cranium in an upright body position, varying from positive to subatmospheric values. So far, these changes have been explained by the Monroe–Kellie doctrine according to which CSFP should increase or decrease if a change in at least one of the three intracranial volumes (brain, blood, and CSF) occurs. According to our hypothesis, changes in intracranial CSFP can occur without a change in the volume of intracranial fluids. To test this hypothesis, we alternately added and removed 100 or 200 μl of fluid from the spinal CSF space of four anesthetized cats and from a phantom which, by its dimensions and biophysical characteristics, imitates the cat cerebrospinal system, subsequently comparing CSFP changes in the cranium and spinal space in both horizontal and vertical positions. The phantom was made from a rigid “cranial” part with unchangeable volume, while the “spinal” part was made of elastic material whose modulus of elasticity was in the same order of magnitude as those of spinal dura. When a fluid volume (CSF or artificial CSF) was removed from the spinal space, both lumbar and cranial CSFP pressures decreased by 2.0–2.5 cm H2O for every extracted 100 μL. On the other hand, adding fluid volume to spinal space causes an increase in both lumbar and cranial CSFP pressures of 2.6–3.0 cm H2O for every added 100 μL. Results observed in cats and phantoms did not differ significantly. The presented results on cats and a phantom suggest that changes in the spinal CSF volume significantly affect the intracranial CSFP, but regardless of whether we added or removed the CSF volume, the hydrostatic pressure difference between the measuring sites (lateral ventricle and lumbar subarachnoid space) was always constant. These results suggest that intracranial CSFP can be increased or decreased without significant changes in the volume of intracranial fluids and that intracranial CSFP changes in accordance with the law of fluid mechanics.

Frameless stereotactic brain biopsy and external ventricular drainage placement using the RONNA G4 system

Robot-assisted stereotactic procedures are among the latest technological improvements in neurosurgery. Herein, to the best of our knowledge, we report a first external ventricular drainage (EVD) placement using the RONNA G4 robotic system preformed together with brain biopsy, all in one procedure. A patient was presented with progressive drowsiness, cognitive slowing, poor mobility and incontinent. Magnetic resonance imaging brain scans revealed multicentric process located in the basal ganglia right with extensive vasogenic edema and dilatated ventricular system. Using the RONNAplan software two trajectories were planned: one for brain biopsy on the left side and one for EVD implantation on the right side; the procedures went without complications. The RONNA G4 robotic system is an accurate neurosurgical tool for performing frameless brain biopsies and EVD placement. Further studies are needed in order to enroll a larger patient sample and to calculate the possible placement deviation, and to perform the comparison with other robotic systems.

Decoding the Role of DVL1 in Intracranial Meningioma

In the search for molecular candidates for targeted meningioma therapies, increasing attention has been paid to the role of signaling pathways in the development and progression of intracranial meningiomas. Although it is well known that the Wnt signaling pathway is involved in meningioma progression, the role of its central mediator, DVL1, is still unclear. In order to investigate the influence of DVL1 gene alterations on the progression of human intracranial meningioma, we focused on its central PDZ domain, which is responsible for DVL interaction with the Fzd receptor and the phosphorylation of DVL mediated through the casein kinases CK1 and CK2. A genetic analysis of genomic instability revealed the existence of microsatellite instability in 9.09% and the loss of heterozygosity in 6.06% of the samples. The sequencing of the PDZ gene region showed repetitive deletions of two bases located in intron 7 and exon 8, and a duplication in intron 8 in most samples, with different outcomes on the biological function of the DVL1 protein. Immunohistochemistry revealed that the nuclear expression of DVL1 was significantly correlated with a higher expression of active β-catenin (p = 0.029) and a higher meningioma grade (p = 0.030), which leads to the conclusion that it could be used as biomarker for meningioma progression and the activation of the Wnt signaling pathway.

Glycemia and venous thromboembolism in patients with primary brain tumors - A speculative review

Venous thromboembolism (VTE) is a significant public health issue causing severe morbidity and mortality. One of the most vulnerable populations for VTE development are cancer patients. And among them, patients with brain tumors have arguably the highest risk of developing this often fatal complication. Hyperglycemia is a well-known factor which leads to a wide variety of pro-thrombotic changes. In this article, we review the current literature on the topic of VTE in brain tumor patients. We also discuss the known correlation between VTE and glycemia, as well as the importance and frequency of glycemia dysregulation in brain tumor patients. Based on the already well-known importance of glucose metabolism in cancer patients, as well as the previous research of our group, we hypothesize that there is a significant number of brain tumor patients who have chronically elevated glycemia, a fact that so-far hasn't been reported. We argue that these patients carry a significantly higher risk of VTE development and would benefit greatly from strict glycemic control. We present our hypothesis, the ways in which to test it, as well as the possible counter-arguments against it. Our hope is that other investigators will be inspired by our article to continue this type of research, since we consider the topic of VTE in brain tumor patients highly important and urgent, primarily due to its prevalence and severity.

No Arachnoid Granulations-No Problems: Number, Size, and Distribution of Arachnoid Granulations From Birth to 80 Years of Age

Introduction: The study aims to quantify changes in the number, size, and distribution of arachnoid granulations during the human lifespan to elucidate their role in cerebrospinal fluid physiology.

Material and Methods: 3T magnetic resonance imaging of the brain was performed in 120 subjects of different ages (neonate, 2 years, 10 years, 20 years, 40 years, 60 years, and 80 years) all with the normal findings of the cerebrospinal fluid system (CSF). At each age, 10 male and 10 female subjects were analyzed. Group scanned at neonatal age was re-scanned at the age of two, while all other groups were scanned once. Arachnoid granulations were analyzed on T2 coronal and axial sections. Each arachnoid granulation was described concerning size and position relative to the superior sagittal, transverse, and sigmoid sinuses and surrounding cranial bones.

Results: Our study shows that 85% of neonates and 2-year-old children do not have visible arachnoid granulations in the dural sinuses and cranial bones on magnetic resonance imaging. With age, the percentage of patients with arachnoid granulations in the superior sagittal sinus increases significantly, but there is no increase in the sigmoid and transverse sinuses. However, numerous individuals in different age groups do not have arachnoid granulations in dural sinuses. Arachnoid granulations in the cranial bones are found only around the superior sagittal sinus, for the first time at the age of 10, and over time their number increases significantly. From the age of 60 onwards, arachnoid granulations were more numerous in the cranial bones than in the dural sinuses.

Conclusion: The results show that the number, size, and distribution of arachnoid granulations in the superior sagittal sinus and surrounding cranial bones change significantly over a lifetime. However, numerous individuals with a completely normal CSF system do not have arachnoid granulations in the dural sinuses, which calls into question their role in CSF physiology. It can be assumed that arachnoid granulations do not play an essential role in CSF absorption as it is generally accepted. Therefore, the lack of arachnoid granulations does not appear to cause problems in intracranial fluid homeostasis.

The Accuracy of Direct Targeting Using Fusion of MR and CT Imaging for Deep Brain Stimulation of the Subthalamic Nucleus in Patients with Parkinson's Disease

INTRODUCTION

 In 33 consecutive patients with Parkinson's disease (PD) undergoing awake deep brain stimulation (DBS) without microelectrode recording (MER), we assessed and validated the precision and accuracy of direct targeting of the subthalamic nucleus (STN) using preoperative magnetic resonance imaging (MRI) and stereotactic computed tomography (CT) image fusion combined with immediate postoperative stereotactic CT and postoperative MRI, and we report on the side effects and clinical results up to 6 months' follow-up.

MATERIALS AND METHODS

 Preoperative nonstereotactic MRI and stereotactic CT images were merged and used for planning the trajectory and final lead position. Immediate postoperative stereotactic CT and postoperative nonstereotactic MRI provided the validation of the final electrode position. Changes in the Unified Parkinson's Disease Rating Scale III (UPDRS III) scores and the levodopa equivalent daily doses (LEDD) and appearance of adverse side effects were assessed.

RESULTS

 The mean Euclidian distance (ED) error between the planned position and the final position of the lead in the left STN was 1.69 ± 0.82 mm and that in the right STN was 2.12 ± 1.00. The individual differences between planned and final position in each of the three coordinates were less than 2 mm. The UPDRS III scores improved by 75% and LEDD decreased by 45%. Few patients experienced complications, such as postoperative infection (n = 1), or unwanted side effects, such as emotional instability (n = 1).

CONCLUSION

 Our results confirm that direct targeting of an STN on stereotactic CT merged with MRI could be a valid method for placement the DBS electrode. The magnitude of our targeting error is comparable with the reported errors when using MER and other direct targeting approaches.

Histological and MRI Study of the Development of the Human Indusium Griseum

To uncover the ontogenesis of the human indusium griseum (IG), 28 post-mortem fetal human brains, 12-40 postconceptional weeks (PCW) of age, and 4 adult brains were analyzed immunohistochemically and compared with post-mortem magnetic resonance imaging (MRI) of 28 fetal brains (14-41 PCW). The morphogenesis of the IG occurred between 12 and 15 PCW, transforming the bilateral IG primordia into a ribbon-like cortical lamina. The histogenetic transition of sub-laminated zones into the three-layered cortical organization occurred between 15 and 35 PCW, concomitantly with rapid cell differentiation that occurred from 18 to 28 PCW and the elaboration of neuronal connectivity during the entire second half of gestation. The increasing number of total cells and neurons in the IG at 25 and 35 PCW confirmed its continued differentiation throughout this period. High-field 3.0 T post-mortem MRI enabled visualization of the IG at the mid-fetal stage using T2-weighted sequences. In conclusion, the IG had a distinct histogenetic differentiation pattern than that of the neighboring intralimbic areas of the same ontogenetic origin, and did not show any signs of regression during the fetal period or postnatally, implying a functional role of the IG in the adult brain, which is yet to be disclosed.

Hemoglobin A1c in Patients with Glioblastoma-A Preliminary Study

BACKGROUND

Glioblastomas are among the most common primary brain tumors with an abysmal prognosis. The significance of glucose metabolism in glioblastoma cell metabolism and proliferation is well-known. However, a significant correlation between the systemic metabolic status of the patient and the cellular proliferation of the glioblastoma has not yet been established.

METHODS

Our aim was to observe and analyze for a possible correlation between glioblastoma cellular proliferation and patients' glycated hemoglobin (HbA1c) levels as a marker of chronic systemic glycemia. We analyzed the data from 25 patients and compared their Ki-67 values with their preoperative HbA1c values.

RESULTS

We observed a statistically significant correlation (P < 0.03) between chronic glycemia (measured using HbA1c) and the cellular proliferation of glioblastoma (measured by cellular Ki-67 expression).

CONCLUSIONS

These results imply a possible positive correlation between glioblastoma cell proliferation and chronic systemic glycemia, a correlation that, to the best of our knowledge, has not yet been reported. Further research in this area could not only lead to a better understanding of glioblastoma but also have significant clinical applications in treating this devastating disease.

HbA1c in patients with intracranial meningiomas WHO grades I and II: A preliminary study

Meningiomas are among the most common primary brain tumors. There is a growing need for novel ways of differentiating between benign (World Health Organization [WHO] grade I) and atypical (WHO grade II) meningiomas as well as for novel markers of the tumor's future behavior. A difference between glucose metabolism in atypical and benign meningiomas is well known. However, a significant correlation between the systemic metabolic status of the patient and the meningioma WHO grade has not yet been established. Our aim was to compare the WHO grades of intracranial meningiomas with the patient's HbA1c levels as a more reliable marker of the chronic systemic metabolic status than the fasting blood glucose value, which is usually looked at. We retrospectively analyzed 15 patients and compared their meningioma WHO grade with their preoperative HbA1c values. Our results show that patients with benign intracranial meningiomas have significantly lower HbA1c value. Conversely, patients with atypical intracranial meningiomas have higher HbA1c values. Furthermore, we showed that the proliferation factor Ki67 was statistically strongly correlated with the HbA1c value (p < .001. These results imply a possible positive correlation between meningioma cell proliferation and the chronic systemic glycemia. Further research in this area could not only lead to better understanding of meningiomas but could have significant clinical application.

Importance of ovarian tissue cryopreservation in fertility preservation and anti-aging treatment

Various oncological and non-oncological diseases, as well as their treatments, can cause premature ovarian insufficiency and reduce a woman's reproductive potential. Fertility preservation is, therefore, becoming an emerging field of reproductive medicine allowing these patients to have their own biological children. The aim of this review is to analyze the importance of ovarian tissue cryopreservation as a fertility preservation method as well as its new role as a hormone replacement treatment. Although ovarian tissue cryopreservation is currently regarded as an experimental procedure, it is rapidly advancing and may become an established fertility preservation method in the near future. This method does not require ovarian stimulation or a subsequent delay in the initiation of cancer treatment. Furthermore, orthotopic ovarian tissue transplantation offers the unique opportunity of spontaneous conception. Due to the restoration of endocrine function following the procedure, ovarian tissue cryopreservation may also be used as tissue hormone replacement therapy in cases of premature ovarian insufficiency, to postpone menopause and prevent its troublesome symptoms and diseases. Even though the role of ovarian tissue cryopreservation as a new anti-aging treatment modality is quite promising, the safety and efficacy of this approach should be investigated in clinical settings.

The Dubrava Model-A Novel Approach in Treating Acutely Neurotraumatized Patients in Rural Areas: A Proposal for Management

Introduction Neurotrauma is one of the leading causes of death and disabilities nowadays and represents one of the largest socioeconomic problems in rich countries, as well as developing ones. A satisfying, medically viable, and cost-effective model of managing acutely neurotraumatized patients, especially ones who come from distant and/or rural areas, has yet to be found. Patient outcome after acute neurotrauma depends on many factors of which the possibility of urgent treatment by an experienced specialist team has a crucial role. Here, we present our own way of managing acutely neurotraumatized patients from distant places which is unique in Croatia, the Dubrava model.

Methods We present our 5-year experience cooperating with general hospitals in four neighboring cities (Ĉakovec, Bjelovar, Sisak, and Koprivnica) in managing, operating, and taking care of acutely neurotraumatized patients.

Results More than 300 surgeries have been performed in these hospitals through the Dubrava model. Our experience so far provides encouraging results that this system could also be successfully implemented in other institutions. Furthermore, we recorded an increased number of surgeries each year, as well as a good mutual cooperation with the local general hospitals.

Discussion This trauma managing model is one of a kind in Croatia. We argue that it is not only better for the patients, providing them with better chances of survival, and disability-free recovery, but is also far superior in many ways to the dominant and currently prevalent way of treating these patients in other parts of Croatia.

Conclusion The Dubrava model of treating patients in rural and distant areas is a reliable and proven model with many benefits and as such its implementation should be considered in other institutions as well.

The Movement of Cerebrospinal Fluid and Its Relationship with Substances Behavior in Cerebrospinal and Interstitial Fluid

The cerebrospinal fluid (CSF) movement and its influence on substance distribution and elimination from the CSF system have been thoroughly analyzed and discussed in the light of the new hypothesis of CSF physiology. As a result, CSF movement is not presented as a circulation, but a permanent rhythmic systolic-diastolic pulsation in all directions. Such movement also represents the main force of substance distribution inside the CSF system. This distribution occurs in all directions, i.e., in the direction of the imagined circulation, as well as in the opposite direction, and depends on the application site and the resident time of tested substance, where longer resident time means longer distribution distance. Transport mechanisms situated on the microvessels inside the central nervous system (CNS) parenchyma play the key role in substance elimination from the CSF and interstitial fluid (ISF) compartments, which freely communicate. If a certain transport mechanism is not available at one site, the substance will be distributed by CSF movement along the CSF system and into the CNS region where that transport mechanism is available. Pharmacological manipulation suggests that the residence time and the substance travel distance along the CSF system depend on the capacity of transport mechanisms situated on CNS blood capillaries. Physiological absorption of the CSF into the venous sinuses and/or lymphatics, due to their small surface area, should be of minor importance in comparison with the huge absorptive surface area of the microvessel network.

Traumatic Optic Neuropathy - Case Report with Discussion on Diagnostic Procedures and Therapy

Traumatic optic neuropathy (TON) is a serious vision threatening condition that can be caused by ocular or head trauma. Indirect damage to the optic nerve is the most common form of TON occurring in 0.5% to 5% of all closed head trauma cases. Although the degree of visual loss after indirect TON may vary, approximately 50% of all patients are left with 'light perception' or 'no light perception' vision, making TON a significant cause of permanent vision loss. We present a 47-year-old male patient with a history of right eye keratoconus following a motorcycle crash. Visual acuity was of 'counting fingers at 2 meters' on the right eye due to keratoconus and 'counting fingers at 1 meter' on the left eye as a consequence of trauma. The Octopus visual field showed diffuse re-duction in retinal sensitivity and the Ishihara color test indicated dysfunction of color perception on the left eye. Relative afferent pupillary defect was also present. Computed tomography revealed multifragmentary fracture of the frontal sinus and the roof of the left orbit without bone displacement. Based on the findings, conservative corticosteroid therapy without surgery was conducted. The patient responded well to treatment with complete ophthalmologic recovery.

The effects of lumboperitoneal and ventriculoperitoneal shunts on the cranial and spinal cerebrospinal fluid volume in a patient with idiopathic intracranial hypertension

Lumboperitoneal (LP) and ventriculoperitoneal (VP) shunts are a frequent treatment modality for idiopathic intracranial hypertension (IIH). Although these shunts have been used for a long time, it is still not clear how they change the total craniospinal CSF volume and what portions of cranial and spinal CSF are affected. This report for the first time presents the results of a volumetric analysis of the total cranial and spinal CSF space in a patient with IIH. We performed an automated segmentation of the cranial and a manual segmentation of the spinal CSF space first with an LP shunt installed and again after the LP shunt was replaced by a VP shunt. When the LP shunt was in place, the total CSF volume was smaller than when the VP shunt was in place (222.4 cm(3) vs 279.2 cm(3)). The difference was almost completely the result of the spinal CSF volume reduction (49.3 cm(3) and 104.9 cm(3) for LP and VP, respectively), while the cranial CSF volume was not considerably altered (173.2 cm(3) and 174.2 cm(3) for LP and VP, respectively). This report indicates that LP and VP shunts in IIH do not considerably change the cranial CSF volume, while the reduction of CSF volume after LP shunt placement affects almost exclusively the spinal part of the CSF system. Our results suggest that an analysis of both the cranial and the spinal part of the CSF space is necessary for therapeutic procedures planning and for an early recognition of numerous side effects that often arise after shunts placement in IIH patients.

New Concepts of Cerebrospinal Fluid Physiology and Development of Hydrocephalus

The goal of this review is the presentation of the new (Bulat-Klarica-Orešković) hypothesis of cerebrospinal fluid (CSF) physiology and the ensuing new concept of hydrocephalus development in light of this hypothesis. The widely accepted classic hypothesis of CSF physiology and the traditional concept of hydrocephalus are contradicted by numerous experimental and clinical data, which consequently results in unsatisfying clinical treatment and patient recovery. Therefore, the newly presented concept of hydrocephalus development and possible future treatments are discussed. A new definition suggests that hydrocephalus is a pathological state in which CSF is excessively accumulated inside the cranial part of the CSF system, predominantly in one or more brain ventricles as a consequence of impaired hydrodynamics of intracranial fluids between CSF, brain, and blood compartments.

Experimental Spinal Stenosis in Cats: New Insight in Mechanisms of Hydrocephalus Development

In our new experimental model of cervical stenosis without inflammation we have tested hypothesis that cranio-spinal communication impairment could lead to hydrocephalus development. Spinal and cranial cerebrospinal fluid (CSF) space separation was obtained with positioning of plastic semiring in epidural space at C2 level in cats. Brain ventricles planimetry, and CSF pressure recording in lateral ventricle (LV) and lumbar subarachnoid space (LSS) were performed in acute and subchronic experiments. In all experiments opening CSF pressures were normal. However, in acute experiments, an infusion of artificial CSF into the LV led to increase of CSF pressure and significant gradient pressure development between LV and LSS due to limited pressure transmission. After 3 or 6 weeks spinal cord atrophy was observed at the site of cervical stenosis, and pressure transmission from LV to LSS was improved as a consequence of spinal tissue atrophy. Planimetry of both the coronal brain slices and the ventricles' surface showed that control ventricular surface was 0.6 ± 0.1% (n = 5), and 1.6 ± 0.2% (n = 4) in animals with subchronic cervical stenosis (P < 0.002). These results support the mentioned hypothesis claiming that CSF volume cranio-spinal displacement impairment could start pathophysiological processes leading to development of hydrocephalus.

Monoamine Neurotransmitter Metabolite Concentration as a Marker of Cerebrospinal Fluid Volume Changes

OBJECTIVE

In our previous papers we demonstrated that changes in blood and cerebrospinal fluid (CSF) osmolarity have a strong influence on CSF pressure and volume, which is in accordance with a new proposed hypothesis of CSF physiology. Thus, acute changes in CSF volume should be reflected in the CSF concentration of different central nervous system (CNS) metabolites.

METHODS

In anesthetized cats (n = 4) we measured the outflow volume of CSF by cisternal free drainage at a negative CSF pressure (-10 cmH2O) before and after the intraperitoneal (i.p.) application of a hypo-osmolar substance (distilled water). In samples of CSF collected at different time intervals (30 min) we measured the concentration of homovanillic acid (HVA).

RESULTS

In spite of fact that constant CSF outflow volume was obtained after a 30-min period in our model, the concentration of HVA gradually increased over time and became stable after 90 min. After the i.p. application of distilled water the outflow CSF volume increased significantly, whereas the concentration of HVA significantly decreased over 30 min.

CONCLUSIONS

The results observed suggest that alterations in serum osmolarity change the CSF volume and concentrations of neurotransmitter metabolites because of the osmotic arrival of water from CNS blood capillaries in all CSF compartments.

Volumetric analysis of cerebrospinal fluid and brain parenchyma in a patient with hydranencephaly and macrocephaly--case report

The aim of this study was to perform for the first time the intracranial volumetric analysis of cerebrospinal fluid (CSF) and brain parenchyma in the supratentorial and infratentorial space in a 30-year-old female patient with hydranencephaly and macrocephaly. A head scan performed using a 3T magnetic resonance was followed by manual segmentation of the brain parenchyma and CSF on T2 coronal brain sections. The volume of CSF and brain parenchyma was measured separately for the supratentorial and infratentorial space. The total volume of the intracranial space was 3645.5 cm³. In the supratentorial space, the volume of CSF was 3375.2 cm³ and the volume of brain parenchyma was 80.3 cm³. In the infratentorial space, the volume of CSF was 101.3 cm³ and the volume of the brain parenchyma was 88.7 cm³. In the supratentorial space, there was severe malacia of almost all brain parenchyma with no visible remnants of the choroid plexuses. Infratentorial structures of the brainstem and cerebellum were hypoplastic but completely developed. Since our patient had no choroid plexuses in the supratentorial space and no obstruction between dural sinuses and CSF, development of hydrocephalus and macrocephaly cannot be explained by the classic hypothesis of CSF physiology with secretion, unidirectional circulation, and absorption as its basic postulates. However, the origin and turnover of the enormous amount of intracranial CSF volume, at least 10-fold larger than normal, and the mechanisms of macroencephaly development could be elucidated by the new hypothesis of CSF physiology recently published by our research team.

Long lasting near-obstruction stenosis of mesencephalic aqueduct without development of hydrocephalus--case report

The aim of this study is to present the five-year longitudinal magnetic resonance imaging (MRI) follow up of a patient with incidental finding of near-obstruction stenosis of the aqueduct of Sylvius due to a large pineal cyst. The patient was scanned 3 times on a 3T MR device using a set of standard structural sequences supplemented with high-resolution constructive interference of steady state (CISS) T2 sequence for precise delineation of the aqueduct of Sylvius and cardiac-gated phase-contrast sequences for the analysis of cerebrospinal fluid (CSF) movement. On all MR scans, the size of the pineal cyst and severity of near-obstruction aqueductal stenosis did not show any morphological changes. There was no significant ventricular enlargement although structural CISS sequence showed a near-obstruction stenosis and cardiac-gated phase-contrast sequences did not detect CSF movement through the aqueduct of Sylvius. Our findings are contradictory to the classic hypothesis of CSF physiology based on secretion, circulation, and absorption of CSF, which states that the impairment of CSF circulation through the aqueduct of Sylvius inevitably leads to a hypertensive hydrocephalus development involving the third and the lateral ventricle. Our research group previously proposed a new hypothesis of CSF physiology, which offers more suitable explanation for such clinical cases.

Measurement of cerebrospinal fluid formation and absorption by ventriculo-cisternal perfusion: what is really measured?

The generally accepted hypothesis on cerebrospinal fluid (CSF) hydrodynamics suggests that CSF is actively formed mainly by the choroid plexuses, circulates unidirectionally along the brain ventricles and subarachnoid space, and is passively absorbed mainly into the dural venous sinuses. CSF formation rate (Vf) has been extensively studied using the ventriculo-cisternal perfusion technique and the results have been used as the key evidence confirming the mentioned hypothesis. This technique and the equation for Vf calculation are based on the assumption that the dilution of the indicator substance is a consequence of the newly formed CSF, ie, that a higher CSF formation rate will result in a higher degree of dilution. However, it has been experimentally shown that the indicator substance dilution inside the CSF system does not occur because of a "newly formed" CSF, but as consequence of a number of other factors (departure of substances into the surrounding tissue, flowing around the collecting cannula into the cortical and spinal subarachnoid space, departure into the contralateral ventricle, etc). This technique allows "calculation" of the CSF formation even in dead animals, in an in vitro model, and in any other part of the CSF system outside the ventricles that is being perfused. Therefore, this method is indirect and any dilution of the indicator substance in the perfusate caused by other reasons would result in questionable and often contradictory conclusions regarding CSF formation rates.

A new look at cerebrospinal fluid movement

Brinker et al. extensively reviewed recent findings about CSF circulation in a recent article: “A new look at cerebrospinal circulation”, but did not analyze some important available data in sufficient detail. For example, our findings as well as some clinical data and experimental results obtained from different animal species, do not support unidirectional CSF circulation but strongly suggest that there are cardiac cycle-dependent systolic-diastolic to-and-fro cranio-spinal CSF movements. These are based on: a) physiological oscillations of arterial and venous blood during cranio-spinal blood circulation; b) respiratory activity, and c) body activity and posture. That kind of complex CSF movement could explain the observed distribution of many different substances in all directions along the CSF system and within central nervous system tissue. It seems that efflux transport systems at capillary endothelium may be more important for brain homeostasis than the removal of metabolites by CSF flow. Thus, when discussing the CSF dynamics we suggest that a more appropriate term would be CSF movement rather than CSF circulation.

The influence of body position on cerebrospinal fluid pressure gradient and movement in cats with normal and impaired craniospinal communication

Intracranial hypertension is a severe therapeutic problem, as there is insufficient knowledge about the physiology of cerebrospinal fluid (CSF) pressure. In this paper a new CSF pressure regulation hypothesis is proposed. According to this hypothesis, the CSF pressure depends on the laws of fluid mechanics and on the anatomical characteristics inside the cranial and spinal space, and not, as is today generally believed, on CSF secretion, circulation and absorption. The volume and pressure changes in the newly developed CSF model, which by its anatomical dimensions and basic biophysical features imitates the craniospinal system in cats, are compared to those obtained on cats with and without the blockade of craniospinal communication in different body positions. During verticalization, a long-lasting occurrence of negative CSF pressure inside the cranium in animals with normal cranio-spinal communication was observed. CSF pressure gradients change depending on the body position, but those gradients do not enable unidirectional CSF circulation from the hypothetical site of secretion to the site of absorption in any of them. Thus, our results indicate the existence of new physiological/pathophysiological correlations between intracranial fluids, which opens up the possibility of new therapeutic approaches to intracranial hypertension.

Body mass index and retinopathy in type 1 diabetic patients

Aim. To investigate whether body mass index (BMI) independently or in correlation with other risk factors is associated with diabetic retinopathy (DR) progression. Methods. The study included 176 patients with type 1 diabetes divided into three groups according to DR status: group 1 (no retinopathy; n = 86), group 2 (mild/moderate nonproliferative DR; n = 33), and group 3 (severe/very severe NPDR or proliferative DR; n = 57). Results. A significant deterioration of HbA1c, an increase in total cholesterol, systolic, diastolic blood pressure, and diabetic nephropathy with the progression of retinopathy were found. DR progression was correlated with diabetes duration, HbA1c, hypertension, total cholesterol, and the presence of nephropathy. In patients without nephropathy, statistical analyses showed that progression of retinopathy increased significantly with higher BMI (gr. 1: 24.03 ± 3.52, gr. 2: 25.36 ± 3.44, gr. 3: 26.93 ± 3.24; P < 0.01). A positive correlation between BMI and a significant deterioration of HbA1c, an increase in cholesterol, triglycerides, and hypertension was observed. Conclusion. BMI in correlation with HbA1c, cholesterol, and hypertension appears to be associated with the progression of DR in type 1 diabetic patients without nephropathy. However, additional studies are required to investigate the pathogenic role of obesity and weight loss in retinal diabetic complications particularly relating to nephropathy.

"Compensated hyperosmolarity" of cerebrospinal fluid and the development of hydrocephalus

Acute osmolar loading of cerebrospinal fluid within one lateral ventricle of dogs was examined as a cause of water extraction from the bloodstream and an increase in intracranial pressure. We have shown that a certain amount of (3)H₂O from the bloodstream enters osmotically loaded cerebrospinal fluid significantly faster, hence causing a significant increase in intracranial pressure. The noted phenomenon in which intracranial pressure still significantly increases, but in which the hyperosmolarity of the cerebrospinal fluid is no longer present, was named "compensated hyperosmolarity". In the case of the sub-chronic application of hyperosmolar solutions into cat ventricles, we observed an increase in cerebrospinal fluid volume and a more pronounced development of hydrocephalus in the area of application, but without significant increase in intracranial pressure and without blockage of cerebrospinal fluid pathways. These results support the newly proposed hypothesis of cerebrospinal fluid hydrodynamics and the ability to develop new strategies for the treatment of cerebrospinal fluid-related diseases.

Dependence of cerebrospinal fluid pressure and volume on the changes in serum osmolarity in cats

OBJECTIVES

To study the effect of blood osmolarity on cerebrospinal fluid (CSF) volume and CSF pressure in cats.

METHODS

Three types of methods were used on anesthetized cats. The first, ventriculo-cisternal perfusion (12.96 μL/min) before and after i.v. application of 20% mannitol; the second, measuring the outflow of CSF by cisternal free drainage; and the third, measuring CSF pressure in the ventricles of an intact CSF system, with the second and third method being performed before and after the i.p. application of a hypo-osmolar substance (distilled water).

RESULTS

In the first group, the application of 20% mannitol led to a significantly reduced (p < 0.005) outflow volume (from 12.60 ± 0.29 to 0.94 ± 0.09 μL/min). In the second group, the outflow CSF volume significantly increased (p < 0.001) after the application of distilled water (from 18.8 ± 0.3 to 28.2 ± 0.7 μL/min). In the third group, after the application of distilled water, the CSF pressure also significantly increased (p < 0.05; from 8.3 ± 0.8 to 16.1 ± 0.14 cm H(2)O).

CONCLUSION

We conclude that changes in serum osmolarity change the CSF volume because of the osmotic gradient between the blood and all of the CSF compartments, and also that the change in CSF pressure is closely associated with changes in CSF volume.

Development of hydrocephalus and classical hypothesis of cerebrospinal fluid hydrodynamics: facts and illusions

According to the classical hypothesis of the cerebrospinal fluid (CSF) hydrodynamics, CSF is produced inside the brain ventricles, than it circulates like a slow river toward the cortical subarachnoid space, and finally it is absorbed into the venous sinuses. Some pathological conditions, primarily hydrocephalus, have also been interpreted based on this hypothesis. The development of hydrocephalus is explained as an imbalance between CSF formation and absorption, where more CSF is formed than is absorbed, which results in an abnormal increase in the CSF volume inside the cranial CSF spaces. It is believed that the reason for the imbalance is the obstruction of the CSF pathways between the site of CSF formation and the site of its absorption, which diminishes or prevents CSF outflow from the cranium. In spite of the general acceptance of the classical hypothesis, there are a considerable number of experimental results that do not support such a hypothesis and the generally accepted pathophysiology of hydrocephalus. A recently proposed new working hypothesis suggests that osmotic and hydrostatic forces at the central nervous system microvessels are crucial for the regulation of interstial fluid and CSF volume which constitute a functional unit. Based on that hypothesis, the generally accepted mechanisms of hydrocephalus development are not plausible. Therefore, the recent understanding of the correlation between CSF physiology and the development of hydrocephalus has been thoroughly presented, analyzed and evaluated, and new insights into hydrocephalus etiopathology have been proposed, which are in accordance with the experimental data and the new working hypothesis.