Virtual Planning and Augmented Reality-Guided Microsurgical Resection of a Frontal Arteriovenous Malformation

Arteriovenous malformations (AVMs) are complex vascular lesions that can pose significant risk for spontaneous hemorrhage, seizures, and symptoms related to ischemia and venous hypertension.1 Microsurgical management of AVMs requires a deep understanding of the surrounding anatomy and precise identification of the lesion characteristics. We demonstrate the use of augmented reality in the localization of arterial feeders and draining veins in relation to bordering normal structures (Video 1). A 66-year-old man presented with several episodes of severe right frontal headaches. Magnetic resonance imaging revealed an AVM along the right frontal pole. Subsequent computed tomography angiography demonstrated arterial supply from the right anterior cerebral artery with venous drainage to the superior sagittal sinus. Due to the size, noneloquent location, and superficial pattern of venous drainage, the patient elected to proceed with microsurgery. A virtual planning platform was used in preparation for surgery. Augmented reality integrated with neuronavigation was used during microsurgical resection. Postoperative angiography showed complete resection of the AVM. The patient was discharged home on postoperative day 3 with no complications. He remains neurologically well at 4 months of follow-up.

Neuropsychological outcome after frontal surgery for pediatric-onset epilepsy with focal cortical dysplasia in adolescent and young adult

OBJECTIVE

We investigated neuropsychological outcome in patients with pharmacoresistant pediatric-onset epilepsy caused by focal cortical dysplasia (FCD), who underwent frontal lobe resection during adolescence and young adulthood.

METHODS

Twenty-seven patients were studied, comprising 15 patients who underwent language-dominant side resection (LDR) and 12 patients who had languagenondominant side resection (n-LDR). We evaluated intelligence (language function, arithmetic ability, working memory, processing speed, visuo-spatial reasoning), executive function, and memory in these patients before and two years after resection surgery. We analyzed the relationship between neuropsychological outcome and resected regions (side of language dominance and location).

RESULTS

Although 75% of the patients showed improvement or no change in individual neuropsychological tests after surgical intervention, 25% showed decline. The cognitive tests that showed improvement or decline varied between LDR and n-LDR. In patients who had LDR, decline was observed in Vocabulary and Phonemic Fluency (both 5/15 patients), especially after resection of ventrolateral frontal cortex, and improvement was observed in WCST-Category (7/14 patients), Block Design (6/15 patients), Digit Symbol (4/15 patients), and Delayed Recall (3/9 patients). In patients who underwent n-LDR, improvement was observed in Vocabulary (3/12 patients), but decline was observed in Block Design (2/9 patients), and WCST-Category (2/9 patients) after resection of dorsolateral frontal cortex; and Arithmetic (3/10 patients) declined after resection of dorsolateral frontal cortex or ventrolateral frontal cortex. General Memory (3/8 patients), Visual Memory (3/8 patients), Delayed Recall (3/8 patients), Verbal Memory (2/9 patients), and Digit Symbol (3/12 patients) also declined after n-LDR.

CONCLUSION

Postoperative changes in cognitive function varied depending on the location and side of the resection. For precise presurgical prediction of neuropsychological outcome after surgery, further prospective studies are needed to accumulate data of cognitive changes in relation to the resection site.

Protocol for postmortem bedside endoscopic procedure to sample human respiratory and olfactory cleft mucosa, olfactory bulbs, and frontal lobe

We present a protocol for the rapid postmortem bedside procurement of selected tissue samples using an endoscopic endonasal surgical technique that we adapted from skull base surgery. We describe steps for the postmortem collection of blood, cerebrospinal fluid, a nasopharyngeal swab, and tissue samples; the clean-up procedure; and the initial processing and storage of the samples. This protocol was validated with tissue samples procured postmortem from COVID-19 patients and can be applied in another emerging infectious disease. For complete details on the use and execution of this protocol, please refer to Khan et al. (2021)1 and Khan et al. (2022).2.

Predictive factors of post-operative apathy in patients with diffuse frontal gliomas undergoing awake brain mapping

Patients with diffuse frontal gliomas often present with post-operative apathy after tumour removal. However, the association between apathy and tumour removal of gliomas from the frontal lobe remains unknown. This study aimed to investigate the factors influencing post-operative apathy after tumour removal in patients with diffuse frontal gliomas. We compared the demographics and clinical characteristics of patients with and without post-operative apathy in a cohort of 54 patients who underwent awake brain mapping for frontal gliomas. The frequency of clinical parameters such as left-sided involvement, high-grade tumour types (WHO grades III, IV), main tumour location in the anterior cingulate gyrus (ACC) and/or dorsolateral prefrontal cortex (DLPFC) and orbitofrontal cortex (OFC) was significantly greater in the apathetic group compared to the non-apathetic group. The apathetic group scored significantly lower on neuropsychological assessments such as the Letter Fluency Test among the Word Fluency Tests than the non-pathetic group (p = .000). Moreover, the scores of Parts 3, and 3-1 of the Stroop test were significantly lower in the apathetic group than those in the non-apathetic group (p = .023, .027, respectively). Multivariate model analysis revealed that the appearance of post-operative apathy was significantly related to side of the of lesion [left vs. right, hazard ratio (HR) = 8.00, 95% confidence interval (CI) = 1.36-46.96, p = .021], location of the main tumour in the frontal lobe (ACC/DLPFC/OFC vs. others, HR = 7.99, 95% CI = 2.16-29.59, p = .002), and the Letter Fluency Test (HR = .37, 95% CI = .15-.90, p = .028). Post-operative apathy is significantly associated with ACC and/or DLPFC and OFC in the left hemisphere of diffuse frontal gliomas. Apathy in frontal gliomas is correlated with a decline in the Letter Fluency Test scores. Therefore, this instrument is a potential predictor of post-operative apathy in patients with diffuse frontal gliomas undergoing awake brain mapping.

Contralateral Interhemispheric Transfalcine Approach to the Basal Ganglia

The contralateral interhemispheric approach provides a robust path into the mesial frontal lobe and basal ganglia structures.1 The use of gravity to retract the dominant frontal lobe allows the surgeon to avoid injury caused by exposure of the dominant hemisphere. The transfalcine corridor, however, is long and often not well illuminated, necessitating the use of lighted instruments. Within the path of approach lie the anterior cerebral arteries, which must be carefully dissected and preserved. Upon opening the falx, the entire mesial frontal lobe and deep basal ganglia structures can be readily accessed. Herein, we present a patient with familial cerebral cavernous malformation-1 syndrome who presented after an acute hemorrhage from a deep basal ganglia cerebral cavernous malformation (Video 1). The patient consented to the procedure. The patient was hemiparetic and aphasic, likely secondary to mass effect from the bleed. The lesion was approached from a contralateral interhemispheric approach and removed completely. The patient's examination improved with removal of the mass lesion. This case demonstrates the utility of this approach for accessing deep corridors within the cerebral cortices.

Awake brain mapping paradigms for nondominant hemisphere gliomas

OBJECTIVE

Traditionally, resection of nondominant hemisphere brain tumors was performed under general anesthesia. An improved understanding of right-lateralized neural networks has led to a paradigm shift in recent decades, where the right or nondominant hemisphere is no longer perceived as "functionally silent." There is an increasing interest in awake brain mapping for nondominant hemisphere resections. The objective of this study was to perform a comprehensive review of the existing brain mapping paradigms for patients with nondominant hemisphere gliomas undergoing awake craniotomies.

METHODS

In accordance with PRISMA guidelines, systematic searches of the Medline, Embase, and American Psychological Association PsycInfo databases were undertaken from database inception to July 1, 2023. Studies providing a description of the intraoperative mapping paradigm used to assess cognition during an awake craniotomy for resection of a nondominant hemisphere glioma were included.

RESULTS

The search yielded 1084 potentially eligible articles. Thirty-nine unique studies reporting on 788 patients were included in the systematic review. The most frequently tested cognitive domains in patients with nondominant hemisphere tumors were spatial attention/neglect (17/39 studies, 43.6%), speech-motor/language (17/39 studies, 43.6%), and social cognition (9/39 studies, 23.1%). Within the frontal lobe, the highest number of positive mapping sites was identified for speech-motor/language, spatial attention/neglect, dual tasking assessing motor and language function, working memory, and social cognition. Within the parietal lobe, eloquence was most frequently found upon testing spatial attention/neglect, speech-motor/language, and calculation. Within the temporal lobe, the assessment of spatial attention/neglect yielded the highest number of positive mapping sites.

CONCLUSIONS

Cognitive testing in the nondominant hemisphere is predominantly focused on evaluating two domains: spatial attention/neglect and the motor aspects of speech/language. Multidisciplinary teams involved in awake brain mapping should consider testing an extended range of functions to minimize the risk of postoperative deficits and provide valuable information about anatomo-functional organization of cognitive networks.

Connectome-guided initiation of dopamine agonists facilitates cognitive recovery after frontal lobe resection: A case report

Abulia is a common problem that manifests following various brain conditions, including brain surgeries. Abulia is felt to be related to dysfunction with the brain's dopamine-dependent circuitry. The role of default mode network (DMN) in its pathogenesis is crucial. In this case report, we detail the presentation of abulia in an elderly woman following surgical resection of a right frontal glioblastoma involving the DMN. Connectomic imaging was used pre-operatively and post-operatively, demonstrating disruption of regions integral to the DMN and the central executive network. We observed a significant cognitive improvement following the administration of levodopa and carbidopa. Preoperative assessment of both anatomical and functional networks can help ensure surgical safety and predict postoperative deficits. This evaluation not only enhances preparedness and facilitates early case diagnosis but also expedites the initiation of prompt and potentially targeted treatments. This case highlights the potential efficacy of levodopa and carbidopa in addressing DMN dysfunction and broadly suggests the potential for connectomics-guided post-operative therapies.

Trans-Interhemispheric Stereoelectroencephalography Depth Electrode Placement for Mesial Frontal Lobe Explorations in Medically Refractory Epilepsy: A Technical Note and Case Series

BACKGROUND

Stereoelectroencephalography (SEEG) is an established and safe methodology for extra-operative invasive monitoring in patients with medical refractory epilepsy. SEEG has several advantages such as the ability to record deep cortical structures, mapping the epileptogenic zone in a three-dimensional manner, and analyze bihemispheric regions without the need for bilateral craniotomies. In patients with bilateral hemispheric hypotheses, especially the mesial surface of frontal lobes, bilateral lead placement is compulsory to further define and localize the epileptogenic zone. In this particular cohort of patients, bilateral monitoring may be accomplished from a single entry point using trans-interhemispheric placement of the electrodes. The use of trans-interhemispheric monitoring offers several advantages including sparing the need for additional leads.

OBJECTIVE

To test the hypothesis that, given the lack of the falx as a limiting structure in the ventral and mesial frontal lobe regions, trans-interhemispheric SEEG placement is feasible and a potential benefit for the SEEG method.

METHODS

We report on 6 patients who underwent bilateral monitoring using trans-interhemispheric SEEG lead placement and discuss the operative technique.

RESULTS

Six patients underwent trans-interhemispheric monitoring, with a median of 3 leads per patient (19 total). Trajectory error was minimal (<0.3 mm), and operating room time was comparable with that in previous reports. All leads were placed without adverse events, mislocalization, electrode hemorrhages, or any other complications. All patients had successful localization of the epileptogenic zone.

CONCLUSION

Trans-interhemispheric SEEG to monitor the mesial wall of frontal lobe regions is technically feasible. No adverse events were observed, suggesting a favorable safety profile.

The Transcaruncular Corridor of the Medial Transorbital Approach to the Frontal Lobe: Technical Nuances and Applications

BACKGROUND AND IMPORTANCE

Medial orbital access through a transcaruncular corridor has yet to be fully characterized as a potential approach to intradural lesions within the skull base. Transorbital approaches present unique potential in the management of complex neurological pathologies and require subspecialty collaboration across multiple disciplines.

CLINICAL PRESENTATION

A 62-year-old man presented with progressive confusion and mild left-sided weakness. He was found to have a right frontal lobe mass with significant vasogenic edema. A comprehensive systemic workup was otherwise unremarkable. A multidisciplinary skull base tumor board conference recommended a medial transorbital approach through transcaruncular corridor, which was performed by neurosurgery and oculoplastics services. Postoperative imaging demonstrated gross total resection of the right frontal lobe mass. Histopathologic evaluation was consistent with amelanotic melanoma with BRAF (V600E) mutation. At his last follow-up visit, 3 months after surgery, the patient did not experience any visual symptoms and had an excellent cosmetic outcome after surgery.

CONCLUSION

The transcaruncular corridor through a medial transorbital approach provides a safe and reliable access to the anterior cranial fossa.

Interhemispheric Transcingulate Sulcus Approach to Deep-Seated Medial Frontal and Parietal Lesions-Fiber Dissection Study With Illustrative Cases

BACKGROUND

Surgery for lesions located in the medial frontal and parietal lobes can be quite challenging for neurosurgeons because of morbidities that may arise from damage to critical midline structures or intact neural tissue that need to be crossed to reach the lesion. In our anatomic studies, the cingulate sulcus was observed as an alternative access route for lesions located in medial frontal and parietal lobes.

OBJECTIVE

To explain the microsurgical anatomy of the medial hemisphere and cingulate sulcus and to demonstrate the interhemispheric transcingulate sulcus approach (ITCSA) with 3 clinical cases.

METHODS

Five formalin-fixed brain specimens, which were frozen at -18 °C for at least 2 weeks and then thawed under tap water, were gradually dissected from medial to lateral. Diffusion fiber tracking performed using DSI Studio software in data was provided by the Human Connectome Project. Clinical data of 3 patients who underwent ITCSA were reviewed.

RESULTS

Cingulate sulcus is an effortlessly identifiable continuous sulcus on the medial surface of the brain. Our anatomic dissection study revealed that the lesions located in the deep medial frontal and parietal lobes can be reached through the cingulate sulcus with minor injury only to the cingulum and callosal fibers. Three patients were treated with ITCSA without any neurological morbidity.

CONCLUSION

Deep-seated lesions in the medial frontal lobe and parietal lobe medial to the corona radiata can be approached by using microsurgical techniques based on anatomic information. ITCSA offers an alternative route to these lesions besides the known lateral transcortical/transsulcal and interhemispheric transcingulate gyrus approaches.

A Super-selective Wada Test Successfully Detected an Artery That Supplied Broca's Area in a Case of Left Frontal Lobe Glioblastoma: Technical Case Report

In cases of malignant gliomas located at language eloquent area, it is often difficult to preoperatively detect those area with functional MRI. Awake surgery is often used to spare the language eloquent area during surgery for such tumors; it is not available for a patient whose intracranial pressure is elevated due to the malignant tumor. The Wada test involves infusing anesthetic agents into the internal carotid artery to determine language dominancy before surgery for epilepsy or brain tumor. The super-selective Wada test is a technique to detect more detailed functional localization by infusing anesthetics into far distal middle cerebral artery branches. We present a 37-year-old man suffering from a left frontal lobe glioblastoma, in whom detection of an artery supplying Broca's area was attempted by a super-selective Wada test. The super-selective Wada test successfully detected the branch of middle cerebral artery supplying Broca's area. Total resection of the contrast-enhancing area was achieved without damaging the artery supplying Broca's area without any neurological sequelae. This is the first report describing the usefulness of the super-selective Wada test in glioblastoma treatment. Our findings suggest that the super-selective Wada test is a powerful and useful means to distinguish the artery that supplies the language area from the tumor feeding artery in cases of tumors in the language eloquent area.

Transorbital craniectomy for treatment of frontal lobe and olfactory bulb neoplasms in two dogs

CASE DESCRIPTION

An 8-year-old spayed female Shih Tzu crossbreed dog (dog 1) and a 13-year-old neutered male Miniature Fox Terrier (dog 2) were evaluated for removal of neoplasms involving both the frontal lobe and olfactory bulb.

CLINICAL FINDINGS

Physical examination revealed decreased menace response and behavioral changes in both dogs. For dog 1, neuroanatomic localization of the lesion was the left forebrain region; for dog 2, neuroanatomic localization of the lesion was the right forebrain region. Both dogs underwent CT, and dog 1 also underwent MRI. Results of diagnostic imaging were consistent with frontal lobe and olfactory bulb neoplasia in both cases. Dog 1 had lysis of the frontal bone adjacent to the neoplasm.

TREATMENT AND OUTCOME

Both dogs underwent a transorbital craniectomy to permit surgical tumor removal. Dog 1 was discharged from the hospital 48 hours after surgery, at which time its mentation and cranial nerve examination findings were considered normal. Dog 2 developed neurologic deterioration after surgery but was ultimately discharged from the hospital after 72 hours, at which time its mentation appeared normal.

CLINICAL RELEVANCE

The transorbital approach to the cranium provided excellent access to facilitate removal of frontal lobe and olfactory bulb neoplasms in these 2 dogs.

Axono-cortical evoked potentials as a new method of IONM for preserving the motor control network: a first study in three cases

BACKGROUND

White matter stimulation in an awake patient is currently the gold standard for identification of functional pathways. Despite the robustness and reproducibility of this method, very little is known about the electrophysiological mechanisms underlying the functional disruption. Axono-cortical evoked potentials (ACEPs) provide a reliable technique to explore these mechanisms.

OBJECTIVE

To describe the shape and spatial patterns of ACEPs recorded when stimulating the white matter of the caudal part of the right superior frontal gyrus while recording in the precentral gyrus.

METHODS

We report on three patients operated on under awake condition for a right superior frontal diffuse low-grade glioma. Functional sites were identified in the posterior wall of the cavity, whose 2-3-mA stimulation generated an arrest of movement. Once the resection was done, axono-cortical potentials were evoked: recording electrodes were put over the precentral gyrus, while stimulating at 1 Hz the white matter functional sites during 30-60 s. Unitary evoked potentials were averaged off-line. Waveform was visually analyzed, defining peaks and troughs, with quantitative measurements of their amplitudes and latencies. Spatial patterns of ACEPs were compared with patients' own and HCP-derived structural connectomics.

RESULTS

Axono-cortical evoked potentials (ACEPs) were obtained and exhibited complex shapes and spatial patterns that correlated only partially with structural connectivity patterns.

CONCLUSION

ACEPs is a new IONM methodology that could both contribute to elucidate the propagation of neuronal activity within a distributed network when stimulating white matter and provide a new technique for preserving motor control abilities during brain tumor resections.

[Anterior transperiinsular approach to the head of the caudate nucleus and mediobasal frontal lobe]

BACKGROUND

The head of the caudate nucleus and adjacent mediobasal frontal lobe are deeply localized and have complex anatomical and topographic relationships with surrounding functionally significant cerebral structures. These aspects determine difficult surgical treatment of pathology in this zone.

OBJECTIVE

To propose a new anterior transperiinsular approach for optimizing surgical access to the head of the caudate nucleus and mediobasal frontal lobe.

MATERIAL AND METHODS

Two patients with cavernoma of the head of the caudate nucleus and oligodendroglioma of the head of the caudate nucleus and mediobasal frontal lobe underwent resection via transsylvian anterior transperiinsular approach in 2018. In both cases, tumors were localized in dominant hemisphere. Standard MRI was performed before and after surgery. Luria's neurological and neuropsychological examination was carried out before surgery, in 7 days after surgery and then every 3 months.

RESULTS

Surgical access was performed via stage-by-stage proximal dissection of Sylvian fissure with visualization of anterior and superior periinsular grooves. After that, periinsular groove was dissected at the base of anterior short gyrus. Then, we moved apart white matter using microinstruments and approached the area of interest. In case of this trajectory, surgical approach was performed at the level of the upper parts of inferior frontooccipital fascicle under the arcuate fascicle. Both patients underwent total resection of tumors that was confirmed by MRI. No pre- and postoperative neurological or neuropsychological abnormalities were observed.

CONCLUSION

Anterior transperiinsular approach provides minimally invasive access to the head of the caudate nucleus and mediobasal frontal lobe. It can be used on dominant hemisphere without significant risk of speech or other cognitive impairments. The advantages of this approach are minimal damage to associative pathways and small distance between periinsular groove and zone of interest. Dissection of commissural fibers of the corpus callosum is not required compared to conventional transcallosal approach.

Approach to Slitlike Ventricles: Parietal-Occipital versus Frontal Burr Catheter Entry Sites

BACKGROUND

Slit ventricles can be a challenging target during shunt catheter insertion. Traditionally, the frontal approach has been considered optimal for small ventricles. At this center, routine use of electromagnetic (EM) stereotactic guidance (Stealth, Medtronic, Dublin, Ireland) has enabled a parietooccipital (P-O) burr hole approach to the frontal horns. We compare shunt placement and revisions required for patients with slit ventricles who had shunts inserted via a P-O approach versus frontal shunt.

METHODS

We studied a retrospective cohort of patients with slit ventricles and a ventricular shunt inserted using EM guidance between 2012 and 2018. Slitlike ventricles were defined as the widest point of the lateral ventricle <3 mm. Outcome measures included placement accuracy and survival using the Kaplan-Meier curve. Optimal final catheter tip location was considered to be the frontal horn of the ipsilateral lateral ventricle.

RESULTS

Eighty-two patients (77 female, 5 male) aged 34.9 ± 10.8 years (mean ± standard deviation) had ventricular shunts inserted for idiopathic intracranial hypertension (n = 63), chiari/syrinx (n = 8), congenital (n = 10), and pseudomeningocele (n = 1). Of those identified, 35 had primary P-O shunts and 46 had frontal shunts. Overall, 94% of cases had the catheter tip sitting in the frontal horn. The P-O approach was just as accurate as the frontal approach. Eight P-O shunts and 9 frontal shunts required revision over a 60-month period. There was no significant different in shunt survival between the 2 approaches (P = 0.37).

CONCLUSIONS

EM-guided placement has enabled the P-O approach to be as safe and with equivalent survival to frontal approach. The accuracy of shunt placement between the 2 approaches was similar.

Supratentorial neuroenteric cyst in children: a case report and brief literature review

Neurenteric cysts are rare developmental lesions typically found outside the central nervous system but when they do, we most likely find them in a spinal (cervical or dorsal) intradural extramedular location, often associated with dysraphism. The more unusual intracranial cases have been published because of its rarity, occurring mostly as a posterior fossa extra-axial cyst, in adults. Supratentorial cases are distinctly infrequent, especially in children, resulting in few case reports and even fewer case reviews. We describe a case of a child with a supratentorial neurenteric cyst and present a brief review of the literature about these cysts in children, a noticeable gap in the literature.

Subfrontal recurrence after cerebellar medulloblastoma resection without local relapse: case-based update

OBJECTIVE

This report detailed four cases of tumor recurrence in the subfrontal region after cerebellar medulloblastoma resection without local relapse and explored the causes of recurrence. In addition, a case-based update and insight into the entity is attempted.

METHODS

All four patients received cerebellar medulloblastoma resection and postoperative radiotherapy. They were admitted to our hospital when they were found to have a recurrent tumor in the subfrontal region of the anterior skull base. All four patients received re-resection of the tumor, which was confirmed to be recurrent medulloblastoma by postoperative pathological results.

RESULTS

All patients received local radiotherapy and temozolomide chemotherapy after recurrent tumor resection. They all died due to multiple organ failure resulting from tumor metastasis to other sites or tumor regrowth within 2 years after the second operation.

CONCLUSION

Medulloblastoma metastasize to the subfrontal region and develop a homogenous recurrence is rare. Underdosage of radiation, a gravity-related sanctuary effect, surgical position, and perioperative hydrocephalus management might be factors contributing to this supratentorial meningeal recurrence. A better prevention of tumor recurrence might be achieved by extensive microsurgical tumor resection in the initial operation and by minimizing the need for a permanent V-P shunt in the treatment of perioperative hydrocephalus as well as by administering full-dose radiotherapy to the region of the cribriform plate in the subfrontal area.

Acute contrecoup epidural hematoma that developed without skull fracture in two adults: two case reports

BACKGROUND

The incidence of acute epidural hematoma not accompanied by fracture is low, and it mostly occurs right below the impact point in children. Acute epidural hematoma on the contralateral side of the impact point without fracture is very rare.

CASE PRESENTATION

Case 1: a 52-year-old Japanese woman fell and was bruised in the left occipital region, and acute epidural hematoma developed in the right frontal region. No fracture line was observed in the right frontal region on head computed tomography or during surgery, and the source of bleeding was the middle meningeal artery. Case 2: a 56-year-old Japanese man fell down the stairs and was bruised in the right occipital region, and acute epidural hematoma developed in the right occipital supra- and infratentorial regions and left frontal region. Separation of the lambdoid suture was noted in the right occipital region, but no fracture line was present in the left frontal region on either head computed tomography or during surgery, and the source of bleeding was the middle meningeal artery.

CONCLUSIONS

Two rare cases of frontal contrecoup acute epidural hematoma without facture near the hematoma were reported. It is possible that the dura mater detaches from the inner surface of the skull due to cavitation theory-related negative pressure and blood vessels in the dura mater are damaged, causing contrecoup acute epidural hematoma even though no fracture occurs, for which careful course observation is necessary.

[A foreign object in the frontal lobe]

In this case report a 77-year-old male tumbled in his lavatory and hit his head against a toilet roll holder. The holder penetrated his eye and orbita and left a 0.5 × 1 cm cylindrical piece of plastic inside his frontal lobe. He was admitted at a neurosurgical department, where the foreign object was removed. In this report, we summarise some of the basic principles of handling patients with a penetrating brain trauma, including risk of infection, control of bleeding and technical considerations before surgically removing a foreign object.

Frontoethmoidal Osteoma with Secondary Intradural Mucocele Extension Causing Frontal Lobe Syndrome and Pneumocephalus: Case Report and Review of Literature

BACKGROUND

Paranasal sinus osteoma is a common, asymptomatic, histologically benign, slow-growing tumor. However, it can give rise to secondary pathologies such as a mucocele in about 50% of the cases. Rarely, intracranial and orbital extension is present, leading to rhinoliquorrhea, pneumocephalus, or neurologic and visual impairment, which might be potentially life-threatening.

CASE DESCRIPTION

A 49-year-old man presented with an acute frontal lobe syndrome and rhinoliquorrhea. Cranial magnetic resonance tomography showed a suspected frontoethmoidal osteoma with a mucocele expanding intradurally into the left frontal lobe. It was accompanied by pneumocephalus and showed communication with the left lateral ventricle. Through a bifrontal craniotomy, in toto resection of the frontoethmoidal bony tumor and the intradural mucocele was performed, while thereafter the frontal sinus was cranialized using a pedunculated periosteal flap. Postoperative recovery was uneventful with complete resolution of the tension pneumocephalus and rhinoliquorrhea and led to an improvement of the frontal lobe syndrome.

CONCLUSIONS

We present a rare case of pneumocephalus caused by a frontoethmoidal osteoma associated with an intradural mucocele. A review of the literature, focusing on the surgical strategies in such cases, is provided.

Progressive cystic lesion in a middle-aged patient with tuberous sclerosis complex: A case report

RATIONALE

Tuberous sclerosis complex (TSC) is an uncommon multiple systems disorder. The main characteristics of the disease in the central nervous system include cortical or subcortical tubers, subependymal nodules, and subependymal giant cell astrocytoma. However, progressive cystic lesions in the cerebral hemispheres have rarely been reported in previous studies of TSC.

PATIENT CONCERNS

We present the case of a 35-year-old man with TSC who was admitted to our hospital for a sudden attack of serious headache, vomiting, and left hemiplegia. Brain computerized tomography and magnetic resonance imaging (MRI) revealed multiple subependymal calcific nodes and multiple cystic lesions in the right frontal, temporal, and parietal lobes. The solid nodule in the lesion demonstrated contrast enhancement.

DIAGNOSES

The patient was diagnosed with TSC, but the properties of the cystic lesion in the brain were unclear and a tumor was suspected.

INTERVENTIONS

Emergency operation was performed immediately. Pathological examination of the lesion revealed a vascular malformation, but no tumor cells.

OUTCOMES

In the fourth year after the surgery, brain MRI revealed a relapse of the cystic mass and surgery was suggested again. However, the patient refused to undergo surgery again.

LESSONS

This case describes an atypical MRI presentation of TSC occurring in middle-age. This condition can cause a life-threatening condition and may recur after surgery. Our finding emphasizes the importance of neuroimaging surveillance in patients older than 25 years old and after lesion resection.

Extraventricular Neurocytoma in the Left Frontal Lobe: A Case Report and Literature Review

BACKGROUND

Neurocytoma is a rare brain neoplasm of neuroepithelial origin that occurs predominantly in the ventricular system adjacent to the interventricular foramen and septum pellucidum. However, extraventricular neurocytoma is an extremely rare entity, with poor clinical, radiologic, and histopathological characterization. Here we report a case of an extraventricular parafalcine neurocytoma in the left frontal lobe. We also examine previously reported cases of extraventricular neurocytoma in an attempt to provide an up-to-date summary of the condition.

METHODS

A literature search was performed using PubMed with specific key terms, inclusion criteria, and exclusion criteria. Selected case studies and case series were then compared, and statistical analyses were performed where appropriate. We report a 59-year-old woman presenting with weakness in her right leg and urinary incontinence. Physical examination revealed muscle strength of grade 3/5 in the right lower extremity. Brain magnetic resonance imaging showed a parafalcine mass in the left frontal lobe, with perilesional edema; the cerebral falx and lateral ventricle were shifted due to the compression. Gross total resection was performed.

RESULTS

Histopathological examination revealed a neurocytoma. Immunohistochemical staining showed diffuse positivity for synaptophysin. MIB-1 staining for Ki-67 antibody showed a labeling index of 20%. No adjuvant radiation or chemotherapy was administered. Brain computed tomography performed at a 3-month follow-up showed no signs of recurrence.

CONCLUSION

Extraventricular neurocytoma occurring in the brain parenchyma is a very rare central nervous system tumor. Its clinical and radiologic manifestations are nonspecific. The diagnosis depends on histopathological and immunohistochemical examination. Surgical resection should be the first-choice treatment.

Trans-falcine and contralateral sub-frontal electrode placement in pediatric epilepsy surgery: technical note

INTRODUCTION

Phase II monitoring with intracranial electroencephalography (ICEEG) occasionally requires bilateral placement of subdural (SD) strips, grids, and/or depth electrodes. While phase I monitoring often demonstrates a preponderance of unilateral findings, individual studies (video EEG, single photon emission computed tomography [SPECT], and positron emission tomography [PET]) can suggest or fail to exclude a contralateral epileptogenic onset zone. This study describes previously unreported techniques of trans-falcine and sub-frontal insertion of contralateral SD grids and depth electrodes for phase II monitoring in pediatric epilepsy surgery patients when concern about bilateral abnormalities has been elicited during phase I monitoring.

METHODS

Pediatric patients with medically refractory epilepsy undergoing stage I surgery for phase II monitoring involving sub-frontal and/or trans-falcine insertion of SD grids and/or depth electrodes at the senior author's institution were retrospectively reviewed. Intra-operative technical details of sub-frontal and trans-falcine approaches were studied, while intra-operative complications or events were noted. Operative techniques included gentle subfrontal retraction and elevation of the olfactory tracts (while preserving the relationship between the olfactory bulb and cribriform plate) to insert SD grids across the midline for coverage of the contralateral orbito-frontal regions. Trans-falcine approaches involved accessing the inter-hemispheric space, bipolar cauterization of the anterior falx cerebri below the superior sagittal sinus, and sharp dissection using a blunt elevator and small blade scalpel. The falcine window allowed contralateral SD strip, grid, and depth electrodes to be inserted for coverage of the contralateral frontal regions.

RESULTS

The study cohort included seven patients undergoing sub-frontal and/or trans-falcine insertion of contralateral SD strip, grid, and/or depth electrodes from February 2012 through June 2015. Five patients (71%) experienced no intra-operative events related to contralateral ICEEG electrode insertion. Intra-operative events of frontal territory venous engorgement (1/7, 14%) due to sacrifice of anterior bridging veins draining into the SSS and avulsion of a contralateral bridging vein (1/7, 14%), probably due to prior anterior corpus callosotomy, each occurred in one patient. There were no intra-operative or peri-operative complications in any of the patients studied. Two patients required additional surgery for supplemental SD strip and/or depth electrodes via burr hole craniectomy to enhance phase II monitoring. All patients proceeded to stage II surgery for resection of ipsilateral epileptogenic onset zones without adverse events.

CONCLUSIONS

Trans-falcine and sub-frontal insertion of contralateral SD strip, grid, and depth electrodes are previously unreported techniques for achieving bilateral frontal coverage in phase II monitoring in pediatric epilepsy surgery. This technique obviates the need for contralateral craniotomy and parenchymal exposure with limited, remediable risks. Larger case series using the method described herein are now necessary.

[Actinomycotic brain abscess in immunocompetent patient]

BACKGROUND

The actinomyces is germ commonly found in the normal flora of the oral cavity and gastro-intestinal and uro-genital tracts. Involvement in other locations is a very uncommon event.

OBJECTIVES

To describe a patient with an actinomicotyc brain abscess CLINICAL CASE: We report the case of a patient who suffered a seizure and decreased level of consciousness. Imaging tests revealed the presence of lesions both in the lung and in the brain. An urgent craniotomy was performed and the diagnosis of actinomicotyc abscess was obtained.

CONCLUSION

We describe the differential characteristics of this type of infection, discussing the diagnostic process and management in detail.

Epilepsy in Adults with Supratentorial Glioblastoma: Incidence and Influence Factors and Prophylaxis in 184 Patients

AIM

To analyze the incidence of epilepsy in adult patients with supratentorial glioblastoma, assess the factors influencing the development of epilepsy in these cases, and evaluate patients' response to antiepileptic drugs (AEDs) in a series of 184 patients.

METHODS

We retrospectively analyzed the 184 adult patients diagnosed with supratentorial glioblastoma. All subjects were treated within our hospital and subsequently died between 2003 and 2013. The incidence of epilepsy was assessed before and after initial resection and reexamined every 2 months thereafter. We evaluated the efficacy of prophylactic AEDs in this patient population based on the gathered incidence data.

RESULTS

Of 184 patients, 43 (23.37%) were diagnosed with epilepsy before their initial resection. The total incidence of epilepsy (both pre- and postoperative) was 68.48%. The prevalence of active epilepsy reached over 80% in patients with epilepsy and survival of greater than 13 months postoperatively. Patients with glioblastoma in the frontal and/or temporal lobes had a higher prevalence of epilepsy. In the 43 patients with preoperative epilepsy, total resection of glioblastoma resulted in significantly lower seizure frequency. Patients who received epilepsy prophylaxis with AEDs for at least 6 months had significantly fewer seizures and higher Karnofsky scores than those receiving AEDs for less than one month or not at all.

CONCLUSION

The incidence of epilepsy in adult patients with glioblastoma was high and responded poorly to AEDs in the short term. However, when taken for longer periods, AEDs can reduce the frequency of seizures in patients with glioblastoma.

Malignant Bilateral Basifrontal Solitary Fibrous Tumor. A Case Report

BACKGROUND

Solitary fibrous tumors are rare benign mesenchymal neoplasms characterized by involvement of many sites all over the body with uncommon presentation within the cranium. Furthermore, malignant bilateral basifrontal solitary fibrous tumor is extremely rare. Although uncommon, this rare entity may be included in the differential diagnosis of frontal tumors in adults, to ensure complete surgical resection. The tumor falls under the spectrum of fibroblastic proliferation and shares close morphological overlap with meningiomas and hemangiopericytomas, posing a diagnostic challenge for the histopathologist.

CASE

We report a case of a malignant solitary fibrous tumor in the bilateral basifrontal region in a 50-year-old woman who presented with intermittent headache and vomiting and was clinicoradiologically diagnosed with meningioma.

CONCLUSION

Clinicoradiological and pathological correlation is required for recognizing the aggressive behavior of this tumor and aiding the clinician for appropriate surgical management (complete surgical resection) and close sequential follow-up.

Epsilon Aminocaproic Acid Pretreatment Provides Neuroprotection Following Surgically Induced Brain Injury in a Rat Model

Neurosurgical procedures can damage viable brain tissue unintentionally by a wide range of mechanisms. This surgically induced brain injury (SBI) can be a result of direct incision, electrocauterization, or tissue retraction. Plasmin, a serine protease that dissolves fibrin blood clots, has been shown to enhance cerebral edema and hemorrhage accumulation in the brain through disruption of the blood brain barrier. Epsilon aminocaproic acid (EAA), a recognized antifibrinolytic lysine analogue, can reduce the levels of active plasmin and, in doing so, potentially can preserve the neurovascular unit of the brain. We investigated the role of EAA as a pretreatment neuroprotective modality in a SBI rat model, hypothesizing that EAA therapy would protect brain tissue integrity, translating into preserved neurobehavioral function. Male Sprague-Dawley rats were randomly assigned to one of four groups: sham (n = 7), SBI (n = 7), SBI with low-dose EAA, 150 mg/kg (n = 7), and SBI with high-dose EAA, 450 mg/kg (n = 7). SBI was induced by partial right frontal lobe resection through a frontal craniotomy. Postoperative assessment at 24 h included neurobehavioral testing and measurement of brain water content. Results at 24 h showed both low- and high-dose EAA reduced brain water content and improved neurobehavioral function compared with the SBI groups. This suggests that EAA may be a useful pretherapeutic modality for SBI. Further studies are needed to clarify optimal therapeutic dosing and to identify mechanisms of neuroprotection in rat SBI models.

Thrombin Preconditioning in Surgical Brain Injury in Rats

The surgical brain injury model replicates neurosurgical brain parenchymal damage. Postsurgical brain edema correlates with postoperative neurological dysfunction. Intranasal administration is a proven method of delivering therapies to brain tissue. Thrombin preconditioning decreased brain edema and improved neurological outcomes in models of ischemic brain injury. We hypothesized thrombin preconditioning in surgical brain injury may improve postoperative brain edema and neurological outcomes. Adult male Sprague-Dawley rats (n = 78) weighing 285-355 g were randomly assigned to sham or pre-injury treatment: one-time pretreatment 1 day prior, one-time pretreatment 5 days prior, and daily preconditioning for 5 days prior. Treatment arms were divided into vehicle or thrombin therapies, and subdivided into intranasal (thrombin 5 units/50 μL 0.9 % saline) or intracerebral ventricular (thrombin 0.1 unit/10 μL 0.9 % saline) administration. Blinded observers performed neurological testing 24 h after brain injury followed immediately by measurement of brain water content. There was a significant difference in ipsilateral brain water content and neurological outcomes between all treatment groups and the sham group. However, there was no change in brain water content or neurological outcomes between thrombin- and vehicle-treated animals. Thrombin preconditioning did not significantly improve brain edema or neurological function in surgical brain injury in rats.

Recombinant Slit2 attenuates neuroinflammation after surgical brain injury by inhibiting peripheral immune cell infiltration via Robo1-srGAP1 pathway in a rat model

BACKGROUND AND PURPOSE

Peripheral immune cell infiltration to the brain tissue at the perisurgical site can promote neuroinflammation after surgical brain injury (SBI). Slit2, an extracellular matrix protein, has been reported to reduce leukocyte migration. This study evaluated the effect of recombinant Slit2 and the role of its receptor roundabout1 (Robo1) and its downstream mediator Slit-Robo GTPase activating protein 1 (srGAP1)-Cdc42 on peripheral immune cell infiltration after SBI in a rat model.

METHODS

One hundred and fifty-three adult male Sprague-Dawley rats (280-350 g) were used. Partial resection of right frontal lobe was performed to induce SBI. Slit2 siRNA was administered by intracerebroventricular injection 24h before SBI. Recombinant Slit2 was injected intraperitoneally 1h before SBI. Recombinant Robo1 used as a decoy receptor was co-administered with recombinant Slit2. srGAP1 siRNA was administered by intracerebroventricular injection 24h before SBI. Post-assessments included brain water content measurement, neurological tests, ELISA, Western blot, immunohistochemistry, and Cdc42 activity assay.

RESULTS

Endogenous Slit2 was increased after SBI. Robo1 was expressed by peripheral immune cells. Endogenous Slit2 knockdown worsened brain edema after SBI. Recombinant Slit2 administration reduced brain edema, neurological deficits, and pro-inflammatory cytokines after SBI. Recombinant Slit2 reduced peripheral immune cell markers cluster of differentiation 45 (CD45) and myeloperoxidase (MPO), as well as Cdc42 activity in the perisurgical brain tissue which was reversed by recombinant Robo1 co-administration and srGAP1 siRNA.

CONCLUSIONS

Recombinant Slit2 improved outcomes by reducing neuroinflammation after SBI, possibly by decreasing peripheral immune cell infiltration to the perisurgical site through Robo1-srGAP1 mediated inhibition of Cdc42 activity. These results suggest that Slit2 may be beneficial to reduce SBI-induced neuroinflammation.

Danish experience with paediatric epilepsy surgery

INTRODUCTION

Epilepsy surgery is increasingly used to treat children with medically intractable epilepsy. This study investigates the aetiology and seizure outcome in Danish children operated between 1996 and 2010.

METHODS

Retrospectively collected data on structural magnetic resonance imaging (MRI) diagnoses, surgical procedures and seizure outcomes classified according to the Engel Classification were used. Changes over time grouped as 1996-2000, 2001-2005 and 2006-2010 were analysed.

RESULTS

A total of 95 children underwent epilepsy surgery. Sixty-three operations were performed in Denmark and 50 abroad. In all, 14 children needed reoperation. The median follow-up period was four years. At the latest follow-up, Engel class I (indicating no disabling seizures) was found in 67% of the patients. Cortical dysplasia, mesial temporal sclerosis and tumour were the most common MRI findings. The percentage of tumours operated decreased over time, and frontal lobe resections increased. In the 2006-2010 period, resections with normal MRI were performed, resulting in a less favourable Engel outcome. Persistent, unexpected complications were seen in three of 113 operations.

CONCLUSIONS

The majority of children who undergo epilepsy surgery have a good, worthwhile seizure outcome. The seizure outcome for Danish children corresponds to that of other epilepsy surgery centres. The clinical criteria for selection of patients changed over time.

FUNDING

none.

TRIAL REGISTRATION

The Danish Data Protection Agency approved the project with record number: 2013-41-2459.

Cystoid angiocentric glioma: A case report and literature review

Angiocentric glioma is a rare subtype of neuroepithelial tumor that is associated with a history of epilepsy. We report a case of cystoid angiocentric glioma associated with an area of calcification. This 25 year old male patient presented with tonic clonic spasm. He underwent craniotomy with complete resection of the lesion. Pathologic specimen showed monomorphous bipolar cells with angiocentric growth pattern.

Positron Emission Tomography Imaging Reveals Auditory and Frontal Cortical Regions Involved with Speech Perception and Loudness Adaptation

Considerable progress has been made in the treatment of hearing loss with auditory implants. However, there are still many implanted patients that experience hearing deficiencies, such as limited speech understanding or vanishing perception with continuous stimulation (i.e., abnormal loudness adaptation). The present study aims to identify specific patterns of cerebral cortex activity involved with such deficiencies. We performed O-15-water positron emission tomography (PET) in patients implanted with electrodes within the cochlea, brainstem, or midbrain to investigate the pattern of cortical activation in response to speech or continuous multi-tone stimuli directly inputted into the implant processor that then delivered electrical patterns through those electrodes. Statistical parametric mapping was performed on a single subject basis. Better speech understanding was correlated with a larger extent of bilateral auditory cortex activation. In contrast to speech, the continuous multi-tone stimulus elicited mainly unilateral auditory cortical activity in which greater loudness adaptation corresponded to weaker activation and even deactivation. Interestingly, greater loudness adaptation was correlated with stronger activity within the ventral prefrontal cortex, which could be up-regulated to suppress the irrelevant or aberrant signals into the auditory cortex. The ability to detect these specific cortical patterns and differences across patients and stimuli demonstrates the potential for using PET to diagnose auditory function or dysfunction in implant patients, which in turn could guide the development of appropriate stimulation strategies for improving hearing rehabilitation. Beyond hearing restoration, our study also reveals a potential role of the frontal cortex in suppressing irrelevant or aberrant activity within the auditory cortex, and thus may be relevant for understanding and treating tinnitus.

[Meningioangiomatosis: a clinicopathological study of five cases]

OBJECTIVE

To investigate the clinicopathologic characteristics of meningioangiomatosis (MA).

METHODS

Five cases of MA were evaluated morphologically by HE and immunohistochemistry on formalin-fixed paraffin-embedded tissue. Clinical information was also obtained. The literature was reviewed. The clinical pathology and biological behavior of MA were discussed.

RESULTS

Five cases of MA were reported, arising in three males and two females, with an age range of 16 to 26 years at diagnosis. All five subjects had intractable seizure disorders, and the duration of illness ranged from 8 months to 18 years. The lesions were resected from the frontal lobe in four patients, and from the temporal lobe in one. All the lesions were confined to the cortex, firm in consistency, without capsules and had poor blood supply. There was focal involvement of the overlying leptomeninges. Microscopically, they showed characteristic features of MA, such as proliferating microvessels with perivascular cuffs of spindle-cell within the cortex. Some had numerous calcifications, others showed acidophilic granular bodies. The cells were positive for EMA and vimentin by immunohistochemistry, and for reticulin by histochemical staining.

CONCLUSIONS

MA is a rare, benign hamartomatous lesion of the central nervous system. It usually presents as plaque-like or nodular mass in the cerebral cortex and the overlying leptomeninges, consisting of meningovascular proliferation and leptomeningeal calcification. In some cases the lesion may show perivascular proliferation of elongated spindle-shaped cells. MA usually affects children and young adults, and is located in the frontal or temporal lobes with variable involvement of the overlying leptomeninges. Clinically, most of sporadic cases have a long history of intractable seizures despite multiantiepileptic drugs. MA has also been reported to coexist with arteriovenous malformations,meningiomas and other tumorous lesions.

Ammonia encephalopathy and awake craniotomy for brain language mapping: cause of failed awake craniotomy

We report the case of an aborted awake craniotomy for a left frontotemporoinsular glioma due to ammonia encephalopathy on a patient taking Levetiracetam, valproic acid and clobazam. This awake mapping surgery was scheduled as a second-stage procedure following partial resection eight days earlier under general anesthesia. We planned to perform the surgery with local anesthesia and sedation with remifentanil and propofol. After removal of the bone flap all sedation was stopped and we noticed slow mentation and excessive drowsiness prompting us to stop and control the airway and proceed with general anesthesia. There were no post-operative complications but the patient continued to exhibit bradypsychia and hand tremor. His ammonia level was found to be elevated and was treated with an infusion of l-carnitine after discontinuation of the valproic acid with vast improvement. Ammonia encephalopathy should be considered in patients treated with valproic acid and mental status changes who require an awake craniotomy with patient collaboration.

[Posterior reversible encephalopathy syndrome after neurosurgery: A literature review]

Posterior reversible encephalopathy syndrome is a clinical-radiological characterized by decreased level of consciousness, seizures, and visual disturbances, as well as radiologically ras brain edema, predominantly in parieto-occipital white matter regions. There are many situations that can trigger the disorder, including the administration of immunosuppressants, chemotherapy agents, hypertensive disorders, and sepsis. The case is described of a patient diagnosed with stage IV prostate adenocarcinoma, receiving chemotherapy, andundergoing a posterior reversible encephalopathy syndrome after surgery for resection of brain metastasis.

Morphological derivation overflow as a result of disruption of the left frontal aslant white matter tract

The frontal aslant tract (FAT) is a recently described major connection between the preSMA and Broca's area, whose functional role remains undefined. In this study we examined a patient presenting a morphological overregularization strategy in a verb generation task during awake surgery. This specific language deficit coincided with brain tumor resection at the level of the left FAT. During the task execution the patient formed the non-existent verbs by applying a morphological derivation rule to the given nouns, instead of retrieving the appropriate verbs. DTI results confirmed left FAT damage. Neuropsychological follow-up showed that this morphological derivation impairment partially persisted after surgery, whereas the results on a wide spectrum of other language-related tasks remained satisfactory. Additionally, we compared the pre- and the post-operational fMRI activation maps for the same verb generation task. We discuss the potential role of the left FAT in the morphological derivation process and in lexical retrieval.

[The interactive neuroanatomical simulation and practical application of frontotemporal transsylvian exposure in neurosurgery]

BACKGROUND AND PURPOSE

There is an increased need for new digital education tools in neurosurgical training. Illustrated textbooks offer anatomic and technical reference but do not substitute hands-on experience provided by surgery or cadaver dissection. Due to limited availability of cadaver dissections the need for development of simulation tools has been augmented. We explored simulation technology for producing virtual reality-like reconstructions of simulated surgical approaches on cadaver. Practical application of the simulation tool has been presented through frontotemporal transsylvian exposure.

METHODS

The dissections were performed on two cadaveric heads. Arteries and veins were prepared and injected with colorful silicon rubber. The heads were rigidly fixed in Mayfield headholder. A robotic microscope with two digital cameras in inverted cone method of image acquisition was used to capture images around a pivot point in several phases of dissections. Multilayered, high-resolution images have been built into interactive 4D environment by custom developed software.

RESULTS

We have developed the simulation module of the frontotemporal transsylvian approach. The virtual specimens can be rotated or tilted to any selected angles and examined from different surgical perspectives at any stage of dissections. Important surgical issues such as appropriate head positioning or surgical maneuvers to expose deep situated neuroanatomic structures can be simulated and studied by using the module.

CONCLUSION

The simulation module of the frontotemporal transsylvian exposure helps to examine effect of head positioning on the visibility of deep situated neuroanatomic structures and study surgical maneuvers required to achieve optimal exposure of deep situated anatomic structures. The simulation program is a powerful tool to study issues of preoperative planning and well suited for neurosurgical training.

Rapid and minimum invasive functional brain mapping by real-time visualization of high gamma activity during awake craniotomy

BACKGROUND

Electrocortical stimulation (ECS) is the gold standard for functional brain mapping during an awake craniotomy. The critical issue is to set aside enough time to identify eloquent cortices by ECS. High gamma activity (HGA) ranging between 80 and 120 Hz on electrocorticogram is assumed to reflect localized cortical processing. In this report, we used real-time HGA mapping and functional neuronavigation integrated with functional magnetic resonance imaging (fMRI) for rapid and reliable identification of motor and language functions.

METHODS

Four patients with intra-axial tumors in their dominant hemisphere underwent preoperative fMRI and lesion resection with an awake craniotomy. All patients showed significant fMRI activation evoked by motor and language tasks. During the craniotomy, we recorded electrocorticogram activity by placing subdural grids directly on the exposed brain surface.

RESULTS

Each patient performed motor and language tasks and demonstrated real-time HGA dynamics in hand motor areas and parts of the inferior frontal gyrus. Sensitivity and specificity of HGA mapping were 100% compared with ECS mapping in the frontal lobe, which suggested HGA mapping precisely indicated eloquent cortices. We found different HGA dynamics of language tasks in frontal and temporal regions. Specificities of the motor and language-fMRI did not reach 85%. The results of HGA mapping was mostly consistent with those of ECS mapping, although fMRI tended to overestimate functional areas.

CONCLUSIONS

This novel technique enables rapid and accurate identification of motor and frontal language areas. Furthermore, real-time HGA mapping sheds light on underlying physiological mechanisms related to human brain functions.

Ectopic cortical anaplastic ependymoma: an unusual case report and literature review

Ependymona occasionally occurs outside the ventricular structures, which is called ectopic ependymona (EE), while pure cortex location is uncommon. However, cortical anaplastic ependymoma (CE) is rare, especially in children. There were only four primary CEs, which is located in the superficial cortex, were reported the age of the patient under 12 years old. The present case is a 20-month-old boy presenting with simple partial seizure was treated in our department. Cranial magnetic resonance imaging (MRI) revealed a fronto-parietal lobe mass of more than 50mm in diameter with mixed signal intensity. Total removal of the mass lesion was performed without any neurological deficit. Pathological examination of the excised tumor were consistent with anaplastic ependymoma (AE). The patient had a good recovery after his surgical resection. Radiotherapy and chemotherapy were not taken into account in view of his age, the favorable site and the complete resection. The management of this unusual tumor is summarized in this paper.

Cerebral correlates of visuospatial neglect: a direct cerebral stimulation study

OBJECTIVE

To assess the role of the superior longitudinal fascicle, the inferior fronto-occipital fascicle, and the posterior parietal lobe in visuospatial attention in humans during awake brain surgery.

EXPERIMENTAL DESIGN

Seven patients with hemispheric gliomas (six in the right hemisphere) entered the study. During surgery in asleep/awake anesthesia, guided by Diffusion Tensor Imaging Fiber Tractography, visuospatial neglect was assessed during direct electrical stimulation by computerized line bisection.

PRINCIPAL OBSERVATIONS

A rightward deviation, indicating left visuospatial neglect, was induced in six of seven patients by stimulation of the parietofrontal connections, in a location consistent with the trajectory of the second branch of the superior longitudinal fascicle. Stimulation of the medial and dorsal white matter of the superior parietal lobule (corresponding to the first branch of the superior longitudinal fascicle), of the ventral and lateral white matter of the supramarginal gyrus (corresponding to the third branch of the superior longitudinal fascicle), and of the inferior occipitofrontal fasciculus, was largely ineffective. Stimulation of the superior parietal lobule (Brodmann's area 7) caused a marked rightward deviation in all of the six assessed patients, while stimulation of Brodmann's areas 5 and 19 was ineffective.

CONCLUSIONS

The parietofrontal connections of the dorso-lateral fibers of the superior longitudinal fascicle (i.e., the second branch of the fascicle), and the posterior superior parietal lobe (Brodmann's area 7) are involved in the orientation of spatial attention. Spatial neglect should be assessed systematically during awake brain surgery, particularly when the right parietal lobe may be involved by the neurosurgical procedure.

[Substantiation of the choice of treatment strategy in isolated traumatic injury of the frontal lobes of the brain]

An analysis of the results of the treatment of 132 patients with isolated traumatic parenchymatous injury of the frontal lobes of the brain was made. The treatment strategy was determined in consideration of the traumatic substratum volume and a combination of neurologic status and instrumental data. There were unfavorable risk factors to the course of traumatic parenchymatous injury of the frontal lobes of the brain such as low initial GCS score, the progression of neurologic deficiency in the presence of contusion hemorrhagic foci in the frontal lobe with the volume more than 25 cm3, shifting of midline structures on 5 mm and more or signs of deformation of basilar region cisterns and the presence of mass-effect according to the tomographic data. The developed algorithm allowed improving the results of treatment and the quality of life for patients with traumatic parenchymatous injury of the frontal lobes of the brain.

Association of functional magnetic resonance imaging indices with postoperative language outcomes in patients with primary brain tumors

OBJECT

Functional MRI (fMRI) has the potential to be a useful presurgical planning tool to treat patients with primary brain tumor. In this study the authors retrospectively explored relationships between language-related postoperative outcomes in such patients and multiple factors, including measures estimated from task fMRI maps (proximity of lesion to functional activation area, or lesion-to-activation distance [LAD], and activation-based language lateralization, or lateralization index [LI]) used in the clinical setting for presurgical planning, as well as other factors such as patient age, patient sex, tumor grade, and tumor volume.

METHODS

Patient information was drawn from a database of patients with brain tumors who had undergone preoperative fMRI-based language mapping of the Broca and Wernicke areas. Patients had performed a battery of tasks, including word-generation tasks and a text-versus-symbols reading task, as part of a clinical fMRI protocol. Individually thresholded task fMRI activation maps had been provided for use in the clinical setting. These clinical imaging maps were used to retrospectively estimate LAD and LI for the Broca and Wernicke areas.

RESULTS

There was a relationship between postoperative language deficits and the proximity between tumor and Broca area activation (the LAD estimate), where shorter LADs were related to the presence of postoperative aphasia. Stratification by tumor location further showed that for posterior tumors within the temporal and parietal lobes, more bilaterally oriented Broca area activation (LI estimate close to 0) and a shorter Wernicke area LAD were associated with increased postoperative aphasia. Furthermore, decreasing LAD was related to decreasing LI for both Broca and Wernicke areas. Preoperative deficits were related to increasing patient age and a shorter Wernicke area LAD.

CONCLUSIONS

Overall, LAD and LI, as determined using fMRI in the context of these paradigms, may be useful indicators of postsurgical outcomes. Whereas tumor location may influence postoperative deficits, the results indicated that tumor proximity to an activation area might also interact with how the language network is affected as a whole by the lesion. Although the derivation of LI must be further validated in individual patients by using spatially specific statistical methods, the current results indicated that fMRI is a useful tool for predicting postoperative outcomes in patients with a single brain tumor.

[Neurophysiological assisted transsulcal approach to a high grade glioma without affect neither motor nor somatosensory function]

INTRODUCTION

Intraoperative mapping and neuronavigation permitted a safe approach through the rolandic sulcus, minimizing the impact onto the motor or somatosensory functions. Fluorescence-guide resection defines a limit that allows a total resection without exceed the border of the tumor.

CASE REPORT

A 39-year-old man who was operated by a tumor placed into the rolandic area. With the patient anesthetized (propofol+remyfentanil), we performed cortical mapping, neuronavigation and fluorescence-guide resection with 5-aminolevulinic acid. Post-resection neurophysiologic assessment showed a minor and highly localized effect onto the somato-sensory system.

CONCLUSION

Rolandic area surgery can be safely performed in anesthetized patients when extensive neurophysiological, anatomical and biological assessments are performed.

Pathology of the optic nerve injury

The optic nerve injury is produced by damaging the optic nerve within a craniocerebral trauma. The anatomo-pathology and the pathology of posttraumatic visual impairments are fundamental data for the therapeutic indications. The microscopic examination reveals only the particular cases of very serious or severe extensive lesions. Damage to the vessels of the optic nerve, damage and break of the optical fibers are responsible for immediate visual impairments and secondary hematomas and edemas involving. The factors for the late appearance of visual impairments are numerous and often confounding.

MATERIAL AND METHODS

In the present research, we have a female patient D.A., aged 29, diagnosed with closed fracture in the right frontal lobe, irradiated to the optic canal; blindness in the right eye.

RESULTS

Break of the optical fibers is a result of bone fragments or of traction and torsion. Damage to the vessels of the optic nerve represents the main cause of blindness for most authors. Traction and torsion of the vessels at the moment of injury may cause thrombosis and small hemorrhages which lead to severe ischemia of the, optical fibers.

CONCLUSIONS

The optic nerve injury is produced by damaging the optic nerve within a craniocerebral trauma, through an indirect mechanism most of the times.

Temporary alopecia after embolization of an arteriovenous malformation

Alopecia after head and neck radiotherapy has been extensively reported in the literature. However, alopecia after endovascular procedures is seldom reported in the dermatological literature. Prolonged fluoroscopic imaging during these procedures may cause serious radiation injuries to the skin, such as dermatitis or alopecia. Radiation-induced temporary alopecia is a peculiar form of radiodermitis that occurs over the areas of the scalp that receive the highest doses of radiation. Although repopulation of alopecic patches occurs spontaneously without treatment, it is important to recognize this disorder to establish a correct diagnosis and inform patients about this transient side effect. We report a 44-year-old woman presenting with temporary alopecia after embolization of an arteriovenous malformation.

A 38-year old woman with a dural based lesion

Isolated intracranial xanthogranulomas arising from the dura mater are extremely rare.We present a case of a symptomatic large right frontoparietal dura based intracranial xanthogranuloma in a 38-year-old female. Xanthogranulomas are benign non-Langerhans cell histiocytic lesions. They are frequently described in the skin of infants and children. Extracutaneous manifestations especially in the central nervous system are highly uncommon. Dural xanthogranulomas usually arise in association with familial hypercholesterolemia, with Erdheim Chester disease (ECD), and with Weber-Christian disease. Our case however, had no such associations. In this report, the authors describe the clinical, radiological and microscopic presentation of this case and the differential diagnoses of intracranial xanthogranuloma.