Hemorrhagic Attitude in Frameless and Frame-Based Stereotactic Biopsy for Deep-Seated Primary Central Nervous System Lymphomas in Immunocompetent Patients: A Multicentric Analysis of the Last Twenty Years.

BACKGROUND: Primary central nervous system lymphoma (PCNSL) is a rare manifestation of aggressive extranodal non-Hodgkin lymphoma. In patients with deep-seated lesions, stereotactic brain biopsy (SBB) is an accepted diagnostic procedure to obtain histopathologic confirmation. OBJECTIVE: The aim of this study was to assess the feasibility, diagnostic yield, safety, and complications of stereotactic procedures in midline and deep-seated PCNSLs. METHODS: Patients selected had received a histopathologic diagnosis of PCNSL localized in deep-seated midline structures, obtained by SBB. The intraoperative frozen section was executed as an integral part of the procedure. Computed tomography scan was performed after surgery. RESULTS: A total of 476 SBBs were performed between January 2000 and December 2019 . Of these SBBs, 91 deep-seated lesions had a histologic diagnosis of PCNSL. A significant increase of the incidence of PCNSL compared with all other diseases was observed (P < 0.0001). Eight patients (8.7%) showed a symptomatic hemorrhage, 4 of whom required craniotomy. There were 4 deaths and 2 cases of permanent morbidity. The hemorrhage risk in the PCNSL group was statistically significant (P = 0.0003) compared with other histotypes. CONCLUSIONS: In suspected cases of PCNSL, a histopathologic diagnosis is necessary to distinguish it from glioblastoma or other, nonmalignant conditions. Deep-seated PCNSLs present a higher risk of biopsy-related morbidity and mortality. Intraoperative frozen section increases the diagnostic yield and reduces the number of sampling procedures. Postoperative computed tomography seems to be warranted in patients with suspected PCNSL.

How is stereotactic brain biopsy evolving? A multicentric analysis of a series of 421 cases treated in Rome over the last sixteen years.

OBJECTIVE: In recent decades, frame-based (FBB) and frame-less stereotactic brain biopsy (FLB) have played a crucial role in defining the diagnosis and management of expanding intracranial lesions in critical areas. During the same period, there have been significant advances in diagnostic imaging, a shift in surgical strategies towards extensive resection in gliomas and new molecular classification of brain tumors. Taking these advances into account, we have evaluated whether significant changes have occurred over the last sixteen years of our clinical practice in terms of frequency, indications, target selection, and the histologic results of stereotactic brain biopsy (SBB) procedures. PATIENTS AND METHODS: We analyzed a series of 421 SBB cases treated between January 2002 and June 2017 in three major neurosurgical institutes in Rome, serving a total of 1.5 million people. Within this series, 94.8% of patients underwent FBB, while, more recently, FLB was performed in 5.2% of cases. The entire period under consideration, running from 2002 to 2017, has been further stratified into four-year time-frames (2002-2005, 2006-2009, 2010-2013, 2014-2017) for the purpose of analysis. RESULTS: The diagnostic yield was 97%. Final diagnoses revealed tumors in 90% of cases and non-neoplastic masses in 7%, while 3% of cases were not conclusive. The morbidity rate was 3% (12 cases) and mortality was 0.7% (3 cases). Intra-operative frozen sections were made in 78% of biopsies. In our three institutes, the number of SBBs decreased steadily throughout the time-frames under consideration. We have also observed a statistically significant reduction in biopsy procedures in lobar lesions, while those performed on the basal ganglia increased and the number of SBBs of multiple masses and lesions of the corpus callosum remained stable. Primary central nervous system diagnosis of lymphomas (PCNSL) was the sole diagnosis whose incidence increased significantly. CONCLUSIONS: Over the last sixteen years, we have witnessed a significant decrease in SBB procedures and a modification in target selection and histologic results. Despite the significant evolution of neuroimaging, an accurate non-invasive diagnosis of intracranial expanding lesions has not yet been achieved. Furthermore, the most recent WHO classification of brain tumors (2016), which incorporates molecular and morphological features, has boosted the need for molecular processing of tissue samples in all expanding brain lesions. For these reasons, it is likely that SBBs will continue to be performed in specific cases, playing a significant role in diagnostic confirmation by providing tissue samples, so as to better assess the biology and the prognosis of cerebral lesions, as well as their sensitivity to standard radio-chemotherapy or to new molecular target therapies.

Frameless nonstereotactic image-guided surgery of supratentorial lesions: introduction to a safe and inexpensive technique.

BACKGROUND: We describe a simple, safe, and inexpensive technique that through the comparison of three-dimensional (3D)-rendered magnetic resonance (MR) images and real anatomy allows us to navigate and remove brain lesions, including those without cortical appearance, by direct recognition of anatomical landmarks. Preoperative planning no longer requires the use of fiducials and can therefore be performed out a stereotactic setting. METHODS: MR Digital Imaging and Communications in Medicine format scans of 93 patients were reconstructed using MRIcro freeware for their three-dimensional rendering (3DR). The main location of the lesions was rolandic or left temporal, and most of them were without cortical appearance (78%). The two-dimensional (2D) sets of images were processed by the software to perform a 3DR, thus obtaining a virtual model of the patient's head. Using the same 2D sets, the edges of the lesion's images were contoured by the region of interest (ROI) tool. In the next step, the ROI was projected onto the surface of the virtual model of the patient's head, thus helping to attain the best identification of the craniotomy area. MRIcro automatic segmentation function, the Brain Extraction Tool (BET), provides a clear 3DR of the cortical surface. We used BET to display gyri, sulci, and perilesional vessels to have further anatomical landmarks to guide the surgical approach. RESULTS: The lesions were accessed through an optimally suited craniotomy. The visual matching of the cortical surface with reconstructed 3D images of the cortex permitted a fast localization of cortical and subcortical lesions. The major limitation is the depth of a lesion deeper than 3 cm. In these cases, the use of frame-based or frameless techniques still seems safer and more advantageous. Conclusions: The shape recognition of the cortical landmarks was not biased by brain distortion because the sulci and cortical vessels almost always had a relationship to each other that was not modified by edema or cerebrospinal fluid leakage. This 3DR allows us to reconstruct a virtual anatomy in an easy, portable, and inexpensive way. In selected cases, this technique represents a valid and safe alternative to the use of costly neuronavigation tools and is potentially helpful in developing countries.

The evolution of the meningeal vascular system in the human genus: From brain shape to thermoregulation.

OBJECTIVES: The imprints of the middle meningeal vessels make it possible to analyze vascularization in fossil specimens. The association between changes in the cortical anatomy and vascular organization raises questions about the actual physiological meaning of these features, most of all when dealing with the origin of the modern human brain. Metabolism and thermoregulation may be relevant factors in influencing morphological adaptations between brain and vessels. This study is aimed at investigating the relationships between endocranial morphology and endocranial vessels in modern humans and to analyze the pattern of heat dissipation through the endocranial surface in fossil specimens. METHODS: Through angiotomography, it is possible to make an anatomical reconstruction of the meningeal and cerebral vessels, providing information on the morphology of the endocranial vascular system. At the same time, digital modeling can be performed to investigate the relationships between the endocranial geometry and physical properties such as heat dissipation patterns in extinct hominids. RESULTS: The middle meningeal network is largely independent from the cerebral vascular system. Furthermore, in adults, the medium and upper tracts of the middle meningeal artery shows scarce or absent blood flow. Parietal bossing in modern humans involves relative cooling of the cortical surface at the supramarginal gyrus. CONCLUSIONS: The evidence does not support a thermoregulatory role for the meningeal vascular network, at least in adult normal blood flow conditions. On the other hand, biomechanical protective functions (hydraulic skeleton for shock adsorption) cannot be ruled out.

The middle meningeal artery: from clinics to fossils.

INTRODUCTION: Although research today ranges from molecular to universe scale, many issues regarding gross anatomy remain totally neglected. Within the framework of the endocranial morphogenesis and evolution, understanding the role and variation of the middle meningeal artery relies upon the very limited, scattered, and descriptive information available. The meninges are supplied by branches originating from both the internal and external carotid arteries, often converging in the same networks and hence raising questions on the homology and embryogenesis of these vessels. The middle meningeal artery is often ligated during craniotomies, with no apparent impairment of the cerebral functional processes. The exact physiological role of this extended vascular system, together with the adaptations and selective pressure associated with its evolutionary characterization, have generally been ignored. THE MIDDLE MENINGEAL VESSELS IN NONHUMAN PRIMATES: Anthropologists have made many attempts to quantify and qualify the differences and variation between and within human and nonhuman primates, with scarce results due to the blurry morphology of the vascular networks. Living apes and humans probably have meningeal vessels originating from different embryogenetic processes, further hampering easy phylogenetic comparisons. Generally, monkeys and apes display a larger component derived from the internal carotid artery and its ophthalmic branch. EVOLUTION AND MORPHOLOGICAL VARIATION IN FOSSIL HOMINIDS: The fossil endocasts partially show the traces of the middle meningeal vessels, allowing some hypotheses on the evolution of these structures. In contrast with modern humans, some extinct groups show a dominance of the posterior branch over the anterior one. The most interesting features are associated with the variation of the middle branch, which supplies the parietal areas. In any case, the most striking difference between the modern and non-modern humans regard the definite increase in the number and complexity of the anastomoses and reticulation in the former. This may be either the simple result of a larger percentage of traces left by the soft tissue or be associated with a more developed vascular network. PERSPECTIVES: Tools are needed to quantify and qualify the morphogenesis and variations of the middle meningeal artery. Supposing these vessels are not strictly necessary in the adult age, the evolutionary pressure shaping their structure may have been associated with early life stages. Apart from oxygenation, another function which deserves attention is thermoregulation, considering the metabolic loadings of the cerebral mass.