Absence of movement disorders after surgical resection of glioma invading the right striatum

Revolutionizing Brain Tumor Care: Emerging Technologies and Strategies

Glioblastoma multiforme (GBM) is one of the most aggressive forms of brain tumor, characterized by a daunting prognosis with a life expectancy hovering around 12-16 months. Despite a century of relentless research, only a select few drugs have received approval for brain tumor treatment, largely due to the formidable barrier posed by the blood-brain barrier. The current standard of care involves a multifaceted approach combining surgery, irradiation, and chemotherapy. However, recurrence often occurs within months despite these interventions. The formidable challenges of drug delivery to the brain and overcoming therapeutic resistance have become focal points in the treatment of brain tumors and are deemed essential to overcoming tumor recurrence. In recent years, a promising wave of advanced treatments has emerged, offering a glimpse of hope to overcome the limitations of existing therapies. This review aims to highlight cutting-edge technologies in the current and ongoing stages of development, providing patients with valuable insights to guide their choices in brain tumor treatment.

Motor outcome after resective surgery for the central lobe gliomas

Background:

Extent of resection (EOR) plays a major role in the prognosis on patients with gliomas, although the postoperative functionality of the patient is of great importance as well. It is why many surgeons advocate to not operate extensively on tumors that involve eloquent regions such as the central lobe. Recent series have demonstrated that it is possible to achieve extensive resections in this area without significantly affecting the functional outcome for these patients. We illustrate this issue with the experience obtained at the National Institute of Neurology and Neurosurgery in Mexico City.

Methods:

This is an observational and retrospective study that included patients that received surgical resection for intracranial gliomas that involved the central lobe at the National Institute of Neurology and Neurosurgery of Mexico, between January 2017 and May 2020. Demographic and clinical variables of the patients at the time of diagnosis were collected as well as tumor morphological variables, surgical adjuncts, and clinical outcomes. Statistical analysis was performed with SPSS software.

Results:

A total of 28 patients were included in the study with 43% of patients having a motor deficit before surgery. The average EOR was 88.6%. Patients presented with worsening of their motor status in the immediate postoperative period in 21% of the cases, although most of the patients recovered within the 1^st month of follow-up. After analyzing all variables, not having a presurgical motor deficit was a statistically significant risk factor for developing a new motor deficit in the immediate postoperative period (P: 0.02).

Conclusion:

A resective surgery for gliomas near or within the central lobe can be performed safely and a satisfactory motor outcome for patients can be achieved without sacrificing the EOR. An intact presurgical motor status is a risk factor for developing a new deficit after surgery.

Neural correlates of consciousness and related disorders: From phenotypic descriptors of behavioral and relative consciousness to cortico-subcortical circuitry

We report a review of medical aspects of the consciousness. The behavioral dimension, phenotypic descriptors, relative consciousness and neural correlates of consciousness and related disorders were addressed successively in a holistic and chronological approach. Consciousness is relative, specific to each individual across time and space. Historically defined as the perception of the self and the environment, it cannot be separated from behaviors, entailing an idea of conscious behavior with metapractic and metagnostic aspects. Observation of spontaneous and evoked overt behavior distinguishes three main types of disorder of consciousness (DoC): coma, vegetative state or unresponsive wakefulness, and minimally conscious or relationally impoverished state. Modern functional exploration techniques, such as imaging, increase the understanding of DoCs and consciousness. Whether consciousness is a superior function and/or an instrumental function is discussed. Neural correlates can be subdivided into two wakefulness pathways (superior thalamic cholinergic and inferior extra-thalamic), and cortico-subcortical circuitry. The deep brain structures are those described in the well-known sensorimotor, associative and limbic loops, as illustrated in the mesolimbic model of DoC. The cortices can be segregated into several overlapping networks: (1) a global workspace including thalamo-cortical loops; (2) the default mode network (DMN) and related intrinsic connectivity networks (i.e., central executive, medial DMN and salience networks); (3) a 3-fold network comprising the fronto-parietal control system and its dorsal and ventral attentional sub-networks, the fronto-parietal executive control network, and the cingulo-opercular salience network; (4) the internal and external cortices, respectively medial, turned toward the self, and lateral, turned toward the environment. The network dynamics is the reflection of consciousness, notably anticorrelations such as the decrease in activity of the posterior cingulate-precuneus regions during attentional tasks. Thanks to recent advances in DoC pathophysiology, further significative therapeutic progress is expected, taking into account the societal context. This depends notably on the dissemination of medical knowledge and its transfer to a wider public.

El lóbulo de la ínsula: Parte 2 - anatomía microquirúrgica y correlación clínico-quirúrgica

Antecedentes:

El conocimiento profundo de la anatomía microquirúrgica del lóbulo de la ínsula es crucial para operar pacientes con tumores en esta región. El objetivo de la segunda parte de este estudio es correlacionar la anatomía microquirúrgica con casos ilustrativos retirados de nuestra casuística de 35 pacientes en los cuales fueron realizados 44 cirugías de tumores en relación con el lóbulo de la ínsula.

Métodos:

A lo largo de marzo de 2007 y agosto de 2014, 44 microcirugías fueron realizadas en 35 pacientes portadores de tumores insulares y los hallazgos de las cirugías y mapeo cerebral se correlacionaron con la anatomía microquirúrgica.

Resultados:

De una serie de 44 pacientes con tumores de la ínsula, la mayoría de los casos eran gliomas de bajo grado de malignidad (29 casos). El inicio de los síntomas en 34 pacientes fue epilepsia, siendo esta refractaria al tratamiento medicamentoso en 12 casos. El grado de resección fue subtotal o total en la mayoría de los casos de la serie. La mejoría en la calidad de vida (epilepsia, etc.) estuvo presente en más de la mitad de los pacientes. El dé cit neurológico permanente estuvo presente en tres pacientes.

Conclusión:

En los tumores insulares, es tan importante el conocimiento profundo de la anatomía, como el saber utilizar e interpretar en tiempo real las observaciones de la monitorización neuro siológica intraoperatoria.

Parte I: Anatomía microquirúrgica tridimensional de la ínsula

Antecedentes:

El lóbulo de la ínsula, o ínsula, se encuentra oculto en la super cie lateral del cerebro. La ínsula está localizada profundamente en el surco lateral o cisura silviana, recubierta por los opérculos frontal, parietal y temporal. Estudiar la compleja anatomía del lóbulo de la ínsula, una de las regiones de mayor complejidad quirúrgica del cerebro humano, y su correlación anatómica con casos quirúrgicos.

Métodos:

En la primera parte de este estudio presentamos los resultados de nuestras disecciones microquirúrgicas en fotografías 2 D y 3D; en la segunda parte de nuestro trabajo, la correlación anatómica con una serie de 44 cirugías en pacientes con tumores de la ínsula, principalmente gliomas, operados entre 2007 y 2014.

Resultados:

Extenso conjunto de bras subcorticales, incluyendo el fascículo uncinado, fronto-occipital inferior y el fascículo arcuato, conectan la ínsula a las regiones vecinas. Varias estructuras anatómicas responsables por dé cits neurológicos severos están íntimamente relacionadas con la cirugía de la ínsula, tales como lesiones de la arteria cerebral Media, cápsula interna, áreas del lenguaje en el hemisferio dominante y arterias lenticuloestriadas.

Conclusión:

El entrenamiento en laboratorio de neuroanatomía, estudio de material impreso en 3D, el conocimiento sobre neuro siología intra-operatoria y el uso de armamento neuroquirúrgico moderno son factores que in uencian en los resultados quirúrgicos.

Comparing Glioblastoma Surgery Decisions Between Teams Using Brain Maps of Tumor Locations, Biopsies, and Resections

Purpose

The aim of glioblastoma surgery is to maximize the extent of resection while preserving functional integrity, which depends on the location within the brain. A standard to compare these decisions is lacking. We present a volumetric voxel-wise method for direct comparison between two multidisciplinary teams of glioblastoma surgery decisions throughout the brain.

Methods

Adults undergoing first-time glioblastoma surgery from 2012 to 2013 performed by two neuro-oncologic teams were included. Patients had had a diagnostic biopsy or resection. Preoperative tumors and postoperative residues were segmented on magnetic resonance imaging in three dimensions and registered to standard brain space. Voxel-wise probability maps of tumor location, biopsy, and resection were constructed for each team to compare patient referral bias, indication variation, and treatment variation. To evaluate the quality of care, subgroups of differentially resected brain regions were analyzed for survival and functional outcome.

Results

One team included 101 patients, and the other included 174; 91 tumors were biopsied, and 181 were resected. Patient characteristics were largely comparable between teams. Distributions of tumor locations were dissimilar, suggesting referral bias. Distributions of biopsies were similar, suggesting absence of indication variation. Differentially resected regions were identified in the anterior limb of the right internal capsule and the right caudate nucleus, indicating treatment variation. Patients with (n = 12) and without (n = 6) surgical removal in these regions had similar overall survival and similar permanent neurologic deficits.

Conclusion

Probability maps of tumor location, biopsy, and resection provide additional information that can inform surgical decision making across multidisciplinary teams for patients with glioblastoma.

Microsurgical anatomy of the central core of the brain

OBJECTIVE

The purpose of this study was to describe in detail the cortical and subcortical anatomy of the central core of the brain, defining its limits, with particular attention to the topography and relationships of the thalamus, basal ganglia, and related white matter pathways and vessels.

METHODS

The authors studied 19 cerebral hemispheres. The vascular systems of all of the specimens were injected with colored silicone, and the specimens were then frozen for at least 1 month to facilitate identification of individual fiber tracts. The dissections were performed in a stepwise manner, locating each gray matter nucleus and white matter pathway at different depths inside the central core. The course of fiber pathways was also noted in relation to the insular limiting sulci.

RESULTS

The insular surface is the most superficial aspect of the central core and is divided by a central sulcus into an anterior portion, usually containing 3 short gyri, and a posterior portion, with 2 long gyri. It is bounded by the anterior limiting sulcus, the superior limiting sulcus, and the inferior limiting sulcus. The extreme capsule is directly underneath the insular surface and is composed of short association fibers that extend toward all the opercula. The claustrum lies deep to the extreme capsule, and the external capsule is found medial to it. Three fiber pathways contribute to form both the extreme and external capsules, and they lie in a sequential anteroposterior disposition: the uncinate fascicle, the inferior fronto-occipital fascicle, and claustrocortical fibers. The putamen and the globus pallidus are between the external capsule, laterally, and the internal capsule, medially. The internal capsule is present medial to almost all insular limiting sulci and most of the insular surface, but not to their most anteroinferior portions. This anteroinferior portion of the central core has a more complex anatomy and is distinguished in this paper as the “anterior perforated substance region.” The caudate nucleus and thalamus lie medial to the internal capsule, as the most medial structures of the central core. While the anterior half of the central core is related to the head of the caudate nucleus, the posterior half is related to the thalamus, and hence to each associated portion of the internal capsule between these structures and the insular surface. The central core stands on top of the brainstem. The brainstem and central core are connected by several white matter pathways and are not separated from each other by any natural division. The authors propose a subdivision of the central core into quadrants and describe each in detail. The functional importance of each structure is highlighted, and surgical approaches are suggested for each quadrant of the central core.

CONCLUSIONS

As a general rule, the internal capsule and its vascularization should be seen as a parasagittal barrier with great functional importance. This is of particular importance in choosing surgical approaches within this region.

Endoscopic considerations treating hydrocephalus caused by basal ganglia and large thalamic tumors

Background:

Deep basal-ganglia and large thalamic (BGT) tumors may cause secondary hydrocephalus by compressing the lateral and third ventricles. The ventricular distortion, as well as the infiltrative nature and friability of these tumors, raise specific considerations and risks when treating these patients. Treatment goals may therefore focus on cerebrospinal fluid (CSF) diversion and tissue sampling, followed by nonsurgical treatment options. We present our experience in applying endoscopic techniques for the initial management of such patients.

Methods:

Over a period of 15 months (January 2013 to April 2014), six patients with BGT tumors presented with signs and symptoms of increased intracranial pressure secondary to hydrocephalus. Data was collected retrospectively, including clinical, surgical, and outcome variables.

Results:

Six patients aged 9–41 years (25.6 ± 12.5) were included. Endoscopic procedures included endoscopic third ventriculostomy (4), septum pellucidotomy (5), foramen of Monro stenting (2), and endoscopic biopsy (3). One patient underwent a ventriculoperitoneal shunt placement and another stereotactic biopsy. Indications for endoscopic treatment included the infiltrative nature of the tumor preventing a resective procedure, combined with clinical deterioration related to increased intracranial pressure secondary to hydrocephalus. Pathology results included anaplastic astrocytoma (3) and anaplastic oligodendroglioma (1). Pathological sampling was not possible in two patients. Five patients enjoyed a good clinical recovery with no associated morbidity. There was one perioperative death, secondary to preoperative herniation.

Conclusions:

Endoscopic surgery may potentially play a significant role in the initial management of patients with large basal ganglia and large thalamic tumors causing obstructive hydrocephalus. Technical nuances and individualized goals are crucial for optimal outcomes.

Subcortical surgical anatomy of the lateral frontal region: human white matter dissection and correlations with functional insights provided by intraoperative direct brain stimulation: laboratory investigation

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.

[Controversy in the management of WHO grade II gliomas in eloquent brain areas: recent literature review]

Recent studies have shown that diffuse grade II gliomas (GGII) located in eloquent brain areas represent over 80% of all GGII. The optimal management of these tumours is still controversial. It has long been considered that surgery is not an option for GGII within eloquent areas, due to the high risk of inducing postoperative sequelae in patients with normal neurological explorations. However, the safety of these surgeries has significantly improved in recent years due to the rapid development of techniques enabling a precise mapping of brain functions. Noninvasive functional neuroimaging techniques have been recently developed, enabling cortical mapping of the entire brain prior to surgical procedures. Such precise data provide a preoperative estimation of the location of eloquent areas in relation to the tumour, which is essential for surgical planning and preoperative assessment of morbidity for various surgical approaches. The intraoperative electrical stimulation (IES) mapping technique consists in the application of a bipolar electrode on the brain tissue, enabling an accurate location of brain functions. This provides unique assistance in GGII resection, as it generates a discrete and transient "virtual" lesion within the eloquent tissue. Tumour removal is then tailored according to functional boundaries in order to optimise the quality of resection and to minimise the risk of postoperative sequelae, preserving quality of life. For patients with a GGII in an eloquent area, the possibility of an early resection should be evaluated by a multidisciplinary neuro-oncology team specialising in the management of such tumours.

Brain Hodotopy: From Esoteric Concept to Practical Surgical Applications

BACKGROUND:

The traditional neurosurgical approach to cerebral lesions is based on the classic view of a rigid brain organization in fixed “eloquent” areas. However, this method is brought into discussion by the conceptual and methodological advances in neurosciences that provide a more dynamic representation of the anatomo-functional distribution of the human central nervous system (CNS).

OBJECTIVE AND METHODS:

We review the relevant literature concerning the main features of the modern CNS representation and their implications in neurosurgical practice.

RESULTS:

The CNS is an integrated, wide, plastic network made up of cortical functional epicenters, “topic organization,” connected by both short-local and large-scale white matter fibers, ie, “hodological organization.” According to this model, called hodotopic, brain function results from parallel streams of information dynamically modulated within an interactive, multimodal, and widely distributed circuit. The application of this framework, which can be studied by combining preoperative, intraoperative, and postoperative mapping techniques, enables the neurosurgeon exploration of the individual anatomo-functional architecture, including neurocognitive and emotional aspects. Thus, it is possible to adapt the surgical approach specifically to each patient and to each lesion according to the individual organization. Several experiences demonstrate the possibility of removing regions traditionally considered inoperable without inducing permanent deficits and the potential use of these areas as a safe passage to deeper territories.

CONCLUSION:

We advocate the more systematic integration of a hodotopical view of the CNS to improve the surgical indications and planning for brain lesions, with the goal of optimizing both the extent of resection and functional outcome.

A personal consecutive series of surgically treated 51 cases of insular WHO Grade II glioma: advances and limitations

Object

Few experiences of insular surgery have been reported. Moreover, there are no large surgical studies with long-term follow-up specifically dedicated to WHO Grade II gliomas involving the insula. In this paper, the author describes a personal consecutive series of 51 cases in which patients underwent surgery for an insular Grade II glioma. On the basis of the functional and oncological results, advances and limitations of this challenging surgery are discussed.

Methods

Fifty-one patients harboring an insular Grade II glioma (revealed by seizures in 50 cases) underwent surgery. Findings on preoperative neurological examination were normal in 45 patients (88%). All surgeries were conducted under cortico-subcortical stimulation, and in the case of 16 patients while awake.

Results

Despite an immediate postoperative worsening in 30 cases (59%), the condition of all but 2 patients (96%) returned to baseline or better. Postoperative MR imaging demonstrated that 77% of resections were total or subtotal. Ten patients underwent a second or third surgery, with no additional deficit. Forty-two patients (82%) are alive with a median follow-up of 4 years.

Conclusions

This is the largest reported experience with insular Grade II glioma surgery. The better knowledge of the insular pathophysiology and the use of intraoperative functional mapping allow the risk of permanent deficit to be minimized (and even enable improvement in quality of life) while increasing the extent of resection and thus the impact on the course of the disease. Therefore, surgical removal must always be considered for insular Grade II glioma. However, this surgery remains challenging, especially within the anterior perforating substance and the posterior part of the (dominant) insula. Additional surgery can be suggested in cases in which the first resection is not complete.

Brain plasticity and tumors

Brain plasticity is the potential of the nervous system to reshape itself during ontogeny, learning or following injuries. The first part of this article reviews the pathophysiological mechanisms underlying plasticity at different functional levels. Such plastic potential means that the anatomo-functional organization of the brain in humans, both physiological and pathological, has flexibility. Patterns of reorganization may differ according to the time-course of cerebral damage, with better functional compensation in more slowly growing lesions. The second part of this review analyzes the interactions between tumor growth and brain reshaping, using non-invasive (neuroimaging) and invasive (electrophysiological) methods of functional mapping. Finally, the therapeutic implications provided by a greater understanding of these mechanisms of cerebral redistribution are explored from a surgical point of view. Enhanced preoperative prediction of an individual's potential for reorganization might be integrated into surgical planning and preserving quality of life through tailored rehabilitation programmes to optimize functional recovery following resection of a brain tumor.

Brain plasticity: From pathophysiological mechanisms to therapeutic applications

Cerebral plasticity, which is the dynamic potential of the brain to reorganize itself during ontogeny, learning, or following damage, has been widely studied in the last decade, in vitro, in animals, and also in humans since the development of functional neuroimaging. In the first part of this review, the main hypotheses about the pathophysiological mechanisms underlying plasticity are presented. At a microscopic level, modulations of synaptic efficacy, unmasking of latent connections, phenotypic modifications and neurogenesis have been identified. At a macroscopic level, diaschisis, functional redundancies, sensory substitution and morphological changes have been described. In the second part, the behavioral consequences of such cerebral phenomena in physiology, namely the "natural" plasticity, are analyzed in humans. The review concludes on the therapeutic implications provided by a better understanding of these mechanisms of brain reshaping. Indeed, this plastic potential might be 'guided' in neurological diseases, using rehabilitation, pharmacological drugs, transcranial magnetic stimulation, neurosurgical methods, and even new techniques of brain-computer interface - in order to improve the quality of life of patients with damaged nervous systems.

Lessons from brain mapping in surgery for low-grade glioma: insights into associations between tumour and brain plasticity

Surgical treatment of low-grade gliomas (LGGs) aims to maximise the amount of tumour tissue resected, while minimising the risk of functional sequelae. In this review I address the issue of how to reconcile these two conflicting goals. First, I review the natural history of LGG-growth, invasion, and anaplastic transformation. Second, I discuss the contribution of new techniques, such as functional mapping, to our understanding of brain reorganisation in response to progressive growth of LGG. Third, I consider the clinical implications of interactions between tumour progression and brain plasticity. In particular, I show how longitudinal studies (preoperative, intraoperative, and postoperative) could allow us to optimise the surgical risk-to-benefit ratios. I will also discuss controversial issues such as defining surgical indications for LGGs, predicting the risk of postoperative deficit, aspects of operative surgical neuro-oncology (eg, preoperative planning and preservation of functional areas and tracts), and postoperative functional recovery.

Evaluation of preoperative high magnetic field motor functional MRI (3 Tesla) in glioma patients by navigated electrocortical stimulation and postoperative outcome

OBJECTIVES

The validity of 3 Tesla motor functional magnetic resonance imaging (fMRI) in patients with gliomas involving the primary motor cortex was investigated by intraoperative navigated motor cortex stimulation (MCS).

METHODS

Twenty two patients (10 males, 12 females, mean age 39 years, range 10-65 years) underwent preoperative fMRI studies, performing motor tasks including hand, foot, and mouth movements. A recently developed high field clinical fMRI technique was used to generate pre-surgical maps of functional high risk areas defining a motor focus. Motor foci were tested for validity by intraoperative motor cortex stimulation (MCS) employing image fusion and neuronavigation. Clinical outcome was assessed using the Modified Rankin Scale.

RESULTS

FMRI motor foci were successfully detected in all patients preoperatively. In 17 of 22 patients (77.3%), a successful stimulation of the primary motor cortex was possible. All 17 correlated patients showed 100% agreement on MCS and fMRI motor focus within 10 mm. Technical problems during stimulation occurred in three patients (13.6%), no motor response was elicited in two (9.1%), and MCS induced seizures occurred in three (13.6%). Combined fMRI and MCS mapping results allowed large resections in 20 patients (91%) (gross total in nine (41%), subtotal in 11 (50%)) and biopsy in two patients (9%). Pathology revealed seven low grade and 15 high grade gliomas. Mild to moderate transient neurological deterioration occurred in six patients, and a severe hemiparesis in one. All patients recovered within 3 months (31.8% transient, 0% permanent morbidity).

CONCLUSIONS

The validation of clinically optimised high magnetic field motor fMRI confirms high reliability as a preoperative and intraoperative adjunct in glioma patients selected for surgery within or adjacent to the motor cortex.

The role of dominant striatum in language: a study using intraoperative electrical stimulations

BACKGROUND

The role of the striatum in language remains poorly understood. Intraoperative electrical stimulation during surgery for tumours involving the caudate nucleus or putamen in the dominant hemisphere might be illuminating.

OBJECTIVES

To study the role of these structures in language, with the aim of avoiding postoperative definitive aphasia.

METHODS

11 patients with cortico-subcortical low grade gliomas were operated on while awake, and striatal functional mapping was done. Intraoperative direct electrical stimulation was used while the patients carried out motor and naming tasks during the resection.

RESULTS

In five cases of glioma involving the dominant putamen, stimulations induced anarthria, while in six cases of glioma involving the dominant caudate, stimulations elicited perseveration. There was no motor effect. The striatum was systematically preserved. Postoperatively, all patients except one had transient dysphasia which resolved within three months.

CONCLUSIONS

There appear to be two separate basal ganglia systems in language, one mediated by the putamen which might have a motor role, and one by the caudate which might have a role in cognitive control. These findings could have implications for surgical strategy in lesions involving the dominant striatum.

Intraoperative subcortical stimulation mapping for hemispherical perirolandic gliomas located within or adjacent to the descending motor pathways: evaluation of morbidity and assessment of functional outcome in 294 patients

OBJECT

Intraoperative stimulation mapping of subcortical white matter tracts during the resection of gliomas has become a valuable surgical adjunct that is used to reduce morbidity associated with tumor removal. The purpose of this retrospective analysis was to assess the morbidity and functional outcome associated with this method, thus allowing the surgeon to predict the likelihood of causing a temporary or permanent motor deficit.

METHODS

In this study, the authors report their experience with intraoperative stimulation mapping to locate subcortical motor pathways in 294 patients who underwent surgery for hemispheric gliomas within or adjacent to the rolandic cortex. Data were collected regarding intraoperative cortical and subcortical stimulation mapping results, along with the patient's neurological status pre- and postoperatively. For patients in whom an additional motor deficit occurred postoperatively, its evolution was examined. Of 294 patients, an additional postoperative motor deficit occurred in 60 (20.4%). Of those 60, 23 (38%) recovered to their preoperative baseline status within the 1st postoperative week. Another 12 (20%) recovered from their postoperative motor deficit by the end of the 4th postoperative week, and 11 more recovered to their baseline status by the end of the 3rd postoperative month. Thus, 46 (76.7%) of 60 patients with postoperative motor deficits regained their baseline function within the first 90 days after surgery. The remaining 14 patients (4.8% of the entire study population of 294) had a persistent motor deficit after 3 months. Patients whose subcortical pathways were identified with stimulation mapping were more prone to develop an additional (temporary or permanent) motor deficit than those in whom subcortical pathways could not be identified (27.5% compared with 13.1%, p = 0.003). This was also true when additional (permanent) motor deficits lasted more than 3 months (7.4% when subcortical pathways were found, compared with 2.1% when they were not found; p = 0.041).

CONCLUSIONS

In patients with gliomas that are located within or adjacent to the rolandic cortex and, thus, the descending motor tracts, stimulation mapping of subcortical pathways enables the surgeon to identify these descending motor pathways during tumor removal and to achieve an acceptable rate of permanent morbidity in these high-risk functional areas.

Transient Foix-Chavany-Marie syndrome after surgical resection of a right insulo-opercular low-grade glioma: case report

OBJECTIVE AND IMPORTANCE

We describe an atypical case of transient Foix-Chavany-Marie syndrome, or faciopharyngoglossomasticatory diplegia with automatic voluntary dissociation, occurring after surgical resection of a right insulo-opercular glioma.

CLINICAL PRESENTATION

A 26-year-old right-handed man experienced partial seizures that were poorly controlled by antiepileptic drugs during a 2-year period as a result of a right insulo-opercular low-grade glioma, leading to the proposal of surgical resection. In addition, 1 year before the operation, the patient experienced a severe brain injury that resulted in a coma. A computed tomographic scan revealed left opercular contusion. The patient recovered completely within 6 months.

INTERVENTION

Intraoperative corticosubcortical electrical functional mapping was performed along the resection, allowing the identification and preservation of the facial and upper limb motor structures. A subtotal removal of the glioma was achieved. The patient had postoperative anarthria, with loss of voluntary muscular functions of the face and tongue, and he had trouble chewing and swallowing. All of these symptoms resolved within 3 months.

CONCLUSION

These findings provide insight into the use of surgery to treat a right insulo-opercular tumor. First, surgeons must be particularly cautious in cases with a potential contralateral lesion (e.g., history of head injury), even if such a lesion is not visible on magnetic resonance imaging scans; preoperative metabolic imaging and electrophysiological investigations should be considered before an operative decision is made. Second, surgeons must perform intraoperative functional mapping to identify and to attempt to preserve the corticosubcortical facial motor structures. A procedure performed while the patient is awake should be discussed to detect the structures involved in chewing and swallowing in cases of suspected bilateral lesions. Third, the patient must be informed of this particular risk before surgery is performed.

Usefulness of intraoperative electrical subcortical mapping during surgery for low-grade gliomas located within eloquent brain regions: functional results in a consecutive series of 103 patients

OBJECT

Although a growing number of authors currently advocate surgery to treat low-grade gliomas, controversy still persists, especially because of the risk of inducing neurological sequelae when the tumor is located within eloquent brain areas. Many researchers performing preoperative neurofunctional imaging and intraoperative electrophysiological methods have recently reported on the usefulness of cortical functional mapping. Despite the frequent involvement of subcortical structures by these gliomas, very few investigators have specifically raised the subject of fiber tracking. The authors in this report describe the importance of mapping cortical and subcortical functional regions by using intraoperative real-time direct electrical stimulations during resection of low-grade gliomas.

METHODS

Between 1996 and 2001, 103 patients harboring a corticosubcortical low-grade glioma in an eloquent area, with no or only mild deficit, had undergone surgery during which intraoperative electrical mapping of functional cortical sites and subcortical pathways was performed throughout the procedure. Both eloquent cortical areas and corresponding white fibers were systematically detected and preserved, thus defining the resection boundaries. Despite an 80% rate of immediate postoperative neurological worsening, 94% of patients recovered their preoperative status within 3 months--10% even improved--and then returned to a normal socioprofessional life. Eighty percent of resections were classified as total or subtotal based on control magnetic resonance images.

CONCLUSIONS

The use of functional mapping of the white matter together with cortical mapping allowed the authors to optimize the benefit/risk ratio of surgery of low-grade glioma invading eloquent regions. Given that preoperative fiber tracking with the aid of neuroimaging is not yet validated, we used intraoperative real-time cortical and subcortical stimulations as a valuable adjunct to the other mapping methods.