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Alessandro De Benedictis, Silvio Sarubbo and Hugues Duffau

Object

Recent neuroimaging and surgical results support the crucial role of white matter in mediating motor and higher-level processing within the frontal lobe, while suggesting the limited compensatory capacity after damage to subcortical structures. Consequently, an accurate knowledge of the anatomofunctional organization of the pathways running within this region is mandatory for planning safe and effective surgical approaches to different diseases. The aim of this dissection study was to improve the neurosurgeon's awareness of the subcortical anatomofunctional architecture for a lateral approach to the frontal region, to optimize both resection and postoperative outcome.

Methods

Ten human hemispheres (5 left, 5 right) were dissected according to the Klingler technique. Proceeding lateromedially, the main association and projection tracts as well as the deeper basal structures were identified. The authors describe the anatomy and the relationships among the exposed structures in both a systematic and topographical surgical perspective. Structural results were also correlated to the functional responses obtained during resections of infiltrative frontal tumors guided by direct cortico-subcortical electrostimulation with patients in the awake condition.

Results

The eloquent boundaries crucial for a safe frontal lobectomy or an extensive lesionectomy are as follows: 1) the motor cortex; 2) the pyramidal tract and premotor fibers in the posterior and posteromedial part of the surgical field; 3) the inferior frontooccipital fascicle and the superior longitudinal fascicle posterolaterally; and 4) underneath the inferior frontal gyrus, the head of the caudate nucleus, and the tip of the frontal horn of the lateral ventricle in the depth.

Conclusions

Optimization of results following brain surgery, especially within the frontal lobe, requires a perfect knowledge of functional anatomy, not only at the cortical level but also with regard to subcortical white matter connectivity.

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Alejandro Fernández Coello, Sophie Duvaux, Alessandro De Benedictis, Ryosuke Matsuda and Hugues Duffau

Neural foundations underlying visual agnosia are poorly understood. The authors present the case of a patient who underwent awake surgery for a right basal temporooccipital low-grade glioma in which direct electrostimulation was used both at the cortical and subcortical level. Brain mapping over the inferior longitudinal fascicle generated contralateral visual hemiagnosia. These original findings are in agreement with recent tractography data that have confirmed the existence of an occipitotemporal pathway connecting occipital visual input to higher-level processing in temporal lobe structures. This is the first report of a true transient visual hemiagnosia elicited through electrostimulation, supporting the crucial role of inferior longitudinal fascicle in visual recognition.

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Ryosuke Matsuda, Alejandro Fernández Coello, Alessandro De Benedictis, Matteo Martinoni and Hugues Duffau

Object

Maximal resection of symptomatic cavernous angioma (CA), including its surrounding gliosis if possible, has been recommended to minimize the risk of seizures or (re)bleeding. However, despite recent neurosurgical advances, such extensive CA removal is still a challenge in eloquent areas. The authors report a consecutive series of patients who underwent awake surgery for CA within the left dominant hemisphere in which intraoperative cortical–subcortical electrical stimulation was used.

Methods

Nine patients harboring a CA that was revealed by seizures in 6 cases and bleeding in 3 cases underwent resection. All CAs were located in the left dominant hemisphere: 3 temporal, 2 insular, 2 parietal, and 2 in the parietotemporal region. Awake mapping was performed in all cases by using intraoperative cortical–subcortical electrical stimulation and ultrasonography (except in 1 insular CA in which a neuronavigation system was used).

Results

Total removal of the CA was achieved in all patients, with identification and preservation of language and sensory-motor structures. In addition, the pericavernomatous gliosis was removed in 7 cases, according to the functional boundaries provided by intraoperative subcortical stimulation. In 2 cases, subcortical mapping revealed eloquent areas within the surrounding gliosis, which was voluntarily avoided. There was no postsurgical permanent deficit, no rebleeding, and no epilepsy in 7 cases (2 patients had rare seizures in the 1st year or two after surgery, and then complete arrest), with a mean follow-up of 28.5 months (range 3–64 months).

Conclusions

These results suggest that intraoperative cortical–subcortical stimulation in awake patients represents a valuable adjunct to image-guided surgery with the aim of selecting the safer surgical approach for CAs involving eloquent areas. Moreover, such online mapping can be helpful when removing the pericavernomatous gliosis while preserving functional structures, which can persist within the hemosiderin rim. Thus, the authors propose that awake surgery be routinely considered, both to optimize the resection and to improve the quality of life through seizure control and avoidance of (re)bleeding for CAs located in the left dominant hemisphere.

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Michele Rizzi, Andrea Trezza, Giuseppe Messina, Alessandro De Benedictis, Angelo Franzini and Carlo Efisio Marras

Neurological surgery offers an opportunity to study brain functions, through either resection or implanted neuromodulation devices. Pathological aggressive behavior in patients with intellectual disability is a frequent condition that is difficult to treat using either supportive care or pharmacological therapy. The bulk of the laboratory studies performed throughout the 19th century enabled the formulation of hypotheses on brain circuits involved in the generation of emotions. Aggressive behavior was also studied extensively. Lesional radiofrequency surgery of the posterior hypothalamus, which peaked in the 1970s, was shown to be an effective therapy in many reported series. As with other surgical procedures for the treatment of psychiatric disorders, however, this therapy was abandoned for many reasons, including the risk of its misuse. Deep brain stimulation (DBS) offers the possibility of treating neurological and psychoaffective disorders through relatively reversible and adaptable therapy. Deep brain stimulation of the posterior hypothalamus was proposed and performed successfully in 2005 as a treatment for aggressive behavior. Other groups reported positive outcomes using target and parameter settings similar to those of the original study. Both the lesional and DBS approaches enabled researchers to explore the role of the posterior hypothalamus (or posterior hypothalamic area) in the autonomic and emotional systems.

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Simone Sangiorgi, Alessandro De Benedictis, Marina Protasoni, Alessandro Manelli, Marcella Reguzzoni, Andrea Cividini, Carlo Dell'Orbo, Giustino Tomei and Sergio Balbi

Object

This study was performed to study the microvascular changes that occur during the first 12 hours after traumatic brain injury (TBI) using the corrosion casting technique.

Methods

The authors performed a qualitative and quantitative morphological study of the changes in cerebral vessels at acute (3 hours) and subacute (12 hours) stages after experimental TBI. They used a model of controlled cortical impact (CCI) injury induced by a recently developed electromagnetic device (impactor), focusing their observations mainly on the microvascular alterations responsible for the formation and maintenance of tissue edema and consequent brain swelling during the first hours after TBI. They used corrosion casting, scanning electron microscopy (SEM), light microscopy, and transmission electron microscopy (TEM) to obtain a morphological qualitative map with both 2D and 3D details.

Results

Scanning electron microscopy analysis of vascular casts documented in 3 dimensions the typical injuries occurring after a TBI: subdural, subarachnoid, and intraparenchymal hemorrhages, along with alterations of the morphological characteristics and architecture of both medium-sized and capillary vessels, including ectasia of pial vessels, sphincter constrictions at the origin of the perforating vessels, focal swelling of perforating vessels, widening of intercellular junctions, and some indirect evidence of structural impairment of endothelial cells. All of these vascular alterations were confirmed in 2D analyses using light microscopy and TEM.

Conclusions

The corrosion casting–SEM technique applied to a CCI experimental model proved to be a reliable method for studying the pathophysiology of the vascular alterations occurring at acute and subacute stages after CCI injury. It was also possible to obtain topographical localization of the vascular and cellular events that usually lead to hyperemia, edema, and brain swelling. Moreover, by applying informatic software to anatomical images it was possible to perform quantification and statistical analysis of the observed events.

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Alessandro De Benedictis, Andrea Trezza, Andrea Carai, Elisabetta Genovese, Emidio Procaccini, Raffaella Messina, Franco Randi, Silvia Cossu, Giacomo Esposito, Paolo Palma, Paolina Amante, Michele Rizzi and Carlo Efisio Marras

OBJECTIVE

During the last 3 decades, robotic technology has rapidly spread across several surgical fields due to the continuous evolution of its versatility, stability, dexterity, and haptic properties. Neurosurgery pioneered the development of robotics, with the aim of improving the quality of several procedures requiring a high degree of accuracy and safety. Moreover, robot-guided approaches are of special interest in pediatric patients, who often have altered anatomy and challenging relationships between the diseased and eloquent structures. Nevertheless, the use of robots has been rarely reported in children. In this work, the authors describe their experience using the ROSA device (Robotized Stereotactic Assistant) in the neurosurgical management of a pediatric population.

METHODS

Between 2011 and 2016, 116 children underwent ROSA-assisted procedures for a variety of diseases (epilepsy, brain tumors, intra- or extraventricular and tumor cysts, obstructive hydrocephalus, and movement and behavioral disorders). Each patient received accurate preoperative planning of optimal trajectories, intraoperative frameless registration, surgical treatment using specific instruments held by the robotic arm, and postoperative CT or MR imaging.

RESULTS

The authors performed 128 consecutive surgeries, including implantation of 386 electrodes for stereo-electroencephalography (36 procedures), neuroendoscopy (42 procedures), stereotactic biopsy (26 procedures), pallidotomy (12 procedures), shunt placement (6 procedures), deep brain stimulation procedures (3 procedures), and stereotactic cyst aspiration (3 procedures). For each procedure, the authors analyzed and discussed accuracy, timing, and complications.

CONCLUSIONS

To the best their knowledge, the authors present the largest reported series of pediatric neurosurgical cases assisted by robotic support. The ROSA system provided improved safety and feasibility of minimally invasive approaches, thus optimizing the surgical result, while minimizing postoperative morbidity.