Treatment for paraganglioma with stereotactic radiotherapy.

BACKGROUND: Paragangliomas (PG) are rare neoplasms of neuroendocrine origin that tend to be highly vascularized, slow-growing, and usually sporadic. To date, common treatment options are surgical resection (SR), with or without radiation therapy (RT), and a watch-and-wait approach. AIM: To evaluate the local control and effectiveness of exclusive fractionated stereotactic RT (FSRT) treatment in unresectable PG (uPG). METHODS: We retrospectively evaluated patients with uPG (medically inoperable or refused SR) treated with FSRT with a Cyberknife System (Accuray Incorporated, Sunnyvale, California). Toxicity and initial efficacy were evaluated. RESULTS: From May 2009 to January 2023, 6 patients with a median age of 68 (range 20-84) were treated with FSRT. The median delivered dose was 21 Gy (range 20-30 Gy) at a median isodose line of 75.5% (range 70%-76%) in 4 fractions (range 3-5 fractions). The median volume was 13.6 mL (range 12.4-65.24 mL). The median cumulative biological effective dose and equivalent dose in 2-Gy fractions were 70 Gy and 37.10 Gy respectively. Site of origin involved were the timpa-nojugular glomus (4/6), temporal bone, and cervical spine. In 1 of the 6 patients, the follow-up was insufficient; 5 of 6 patients showed a 5-year overall survival and 5-year progression-free survival of 100%. We observed negligible toxicities during and after RT. The majority of patients showed stable symptoms during follow-up. Only 1 patient developed spine metastases. CONCLUSION: Our preliminary results on this small cohort of patients suggest that FSRT could be an effective and safe alternative to SR.

Linear Scalp Incision in Brain Tumor Surgery: Intraoperative and Postoperative Considerations.

BACKGROUND: Although the linear scalp incision is commonly used in neurosurgical practice, a systematic study elucidating its pros and cons in a specific surgical setting is lacking. Herein, we analyzed our experience with linear scalp incision in brain tumor surgery and the impact on intraoperative variables and postoperative complications. METHODS: Patients undergoing brain tumor surgery (January 2014-December 2021) at 2 neurosurgical departments were included and divided into 2 groups: linear or flap scalp incision. Patients' demographics characteristics, surgical variables, and wound-related complications were analyzed. RESULTS: More than a total of 1036 craniotomies, linear incision (mean length 6cm) was adopted in 282 procedures (27.2%). Mean maximum diameter of the craniotomy was 5.25 cm, with no statistical difference between the 2 groups. In emergency surgery (36 cases), the linear and flap incisions were used indifferently. Linear incision was predominant in supratentorial and suboccipital lesions. Flap incision was significantly more frequent among meningiomas (P < 0.01). Neuronavigation, operative microscope, and subgaleal drain were more frequently used in the flap scalp incision group (P = 0.01). Overall complication rate was comparable to flap scalp opening (P = 0.40). CONCLUSIONS: The use of the linear incision was broadly applied for the removal of supratentorial and suboccipital tumors granting adequate surgical exposure with a low rate of postoperative complications. Tumors skull base localization resulted the only factor hindering the use of the linear incision. The choice of 1 incision over another didn't show to have any impact on intraoperative and postoperative variables, and it remains mainly based on surgeon expertise/preference.

Exploring Deep Cervical Compartments in Head and Neck Surgical Oncology through Augmented Reality Vision: A Proof of Concept.

BACKGROUND: Virtual surgical planning allows surgeons to meticulously define surgical procedures by creating a digital replica of patients' anatomy. This enables precise preoperative assessment, facilitating the selection of optimal surgical approaches and the customization of treatment plans. In neck surgery, virtual planning has been significantly underreported compared to craniofacial surgery, due to a multitude of factors, including the predominance of soft tissues, the unavailability of intraoperative navigation and the complexity of segmenting such areas. Augmented reality represents the most innovative approach to translate virtual planning for real patients, as it merges the digital world with the surgical field in real time. Surgeons can access patient-specific data directly within their field of view, through dedicated visors. In head and neck surgical oncology, augmented reality systems overlay critical anatomical information onto the surgeon's visual field. This aids in locating and preserving vital structures, such as nerves and blood vessels, during complex procedures. In this paper, the authors examine a series of patients undergoing complex neck surgical oncology procedures with prior virtual surgical planning analysis. For each patient, the surgical plan was imported in Hololens headset to allow for intraoperative augmented reality visualization. The authors discuss the results of this preliminary investigation, tracing the conceptual framework for an increasing AR implementation in complex head and neck surgical oncology procedures.

Novel Advances in Treatment of Meningiomas: Prognostic and Therapeutic Implications.

Meningiomas are the most frequent histotypes of tumors of the central nervous system. Their incidence is approximately 35% of all primary brain tumors. Although they have the status of benign lesions, meningiomas are often associated with a decreased quality of life due to focal neurological deficits that may be related. The optimal treatment is total resection. Histological grading is the most important prognostic factor. Recently, molecular alterations have been identified that are specifically related to particular phenotypes and, probably, are also responsible for grading, site, and prognostic trend. Meningiomas recur in 10-25% of cases. In these cases, and in patients with atypical or anaplastic meningiomas, the methods of approach are relatively insufficient. To date, data on the molecular biology, genetics, and epigenetics of meningiomas are insufficient. To achieve an optimal treatment strategy, it is necessary to identify the mechanisms that regulate tumor formation and progression. Combination therapies affecting multiple molecular targets are currently opening up and have significant promise as adjuvant therapeutic options. We review the most recent literature to identify studies investigating recent therapeutic treatments recently used for meningiomas.

Surgical Treatment of Spheno-Orbital Meningiomas: A Systematic Review and Meta-Analysis of Surgical Techniques and Outcomes.

BACKGROUND: Spheno-orbital meningiomas (SOMs) are rare tumors arising from the meninges surrounding the sphenoid bone and orbital structures. Surgical resection is the primary treatment approach for SOMs. Several surgical approaches have been described during the decades, including microsurgical transcranial (MTAs), endoscopic endonasal (EEAs), endoscopic transorbital (ETOAs), and combined approaches, and the choice of surgical approach remains a topic of debate. PURPOSE: This systematic review and meta-analysis aim to compare the clinical and surgical outcomes of different surgical approaches used for the treatment of SOMs, discussing surgical techniques, outcomes, and factors influencing surgical decision making. METHODS: A comprehensive literature review of the databases PubMed, Ovid MEDLINE, and Ovid EMBASE was conducted for articles published on the role of surgery for the treatment of SOMs until 2023. The systematic review was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines. Meta-analysis was performed to estimate pooled event rates and assess heterogeneity. Fixed- and random-effects were used to assess 95% confidential intervals (CIs) of presenting symptoms, outcomes, and complications. RESULTS: A total of 59 studies comprising 1903 patients were included in the systematic review and meta-analysis. Gross total resection (GTR) rates ranged from 23.5% for ETOAs to 59.8% for MTAs. Overall recurrence rate after surgery was 20.7%. Progression-free survival (PFS) rates at 5 and 10 years were 75.5% and 49.1%, respectively. Visual acuity and proptosis improvement rates were 57.5% and 79.3%, respectively. Postoperative cranial nerve (CN) focal deficits were observed in 20.6% of cases. The overall cerebro-spinal fluid (CSF) leak rate was 3.9%, and other complications occurred in 13.9% of cases. MTAs showed the highest GTR rates (59.8%, 95%CI = 49.5-70.2%; p = 0.001) but were associated with increased CN deficits (21.0%, 95%CI = 14.5-27.6%). ETOAs had the lowest GTR rates (23.5%, 95%CI = 0.0-52.5%; p = 0.001), while combined ETOA and EEA had the highest CSF leak rates (20.3%, 95%CI = 0.0-46.7%; p = 0.551). ETOAs were associated with better proptosis improvement (79.4%, 95%CI = 57.3-100%; p = 0.002), while anatomical class I lesions were associated with better visual acuity (71.5%, 95%CI = 63.7-79.4; p = 0.003) and proptosis (60.1%, 95%CI = 38.0-82.2; p = 0.001) recovery. No significant differences were found in PFS rates between surgical approaches. CONCLUSION: Surgical treatment of SOMs aims to preserve visual function and improve proptosis. Different surgical approaches offer varying rates of GTR, complications, and functional outcomes. A multidisciplinary approach involving a skull base team is crucial for optimizing patient outcomes.

The impact of COVID-19 pandemic on surgical neuro-oncology: A survey from the Italian society of neurosurgery (SINch).

Background: The COVID-19 pandemic and its impact on hospitals' activity and organization has imposed a vast change in standard neurosurgical oncology practice to accommodate for shifting resources. Aims: This investigation aims to analyse the nationwide capability in reorganizing the surgical neuro-oncological activity during the COVID-19 pandemic to evaluate whether COVID-19-pandemic influenced the surgical management in these patients. Method: A web-based dataset model organized by the Italian Neurosurgical Society (SINCh) was sent to all the Italian neurosurgical departments in May 2021, requesting to report the types and numbers of surgical procedures performed in the pre-pandemic period (from March 9th 2019 to March 9th 2020) compared to the pandemic period (from March 10th 2020 to March 10th 2021). Results: This multicentre investigation included the surgical activity of 35 Italian Neurosurgical Departments in a pre-pandemic year versus a pandemic year. During the COVID period, 699 fewer neuro-oncological patients were operated on than in the pre-COVID period. We noted a slight increase in urgency and a more severe decrease in elective and benign pathology. None of these differences was statistically significant. Surgically treated patients who tested positive for SARS-CoV-2 were 36, of which 11 died. Death was found to be COVID-related only in 2 cases. Conclusion: The reorganization of the Italian Neurosurgical Departments was able to guarantee a redistribution of the CNS tumors during the inter-pandemic periods, demonstrating that patients even in the pandemic era could be treated without compromising the efficacy and safety of the surgical procedure.

Surgical management of Glioma Grade 4: technical update from the neuro-oncology section of the Italian Society of Neurosurgery (SINch®): a systematic review.

PURPOSE: The extent of resection (EOR) is an independent prognostic factor for overall survival (OS) in adult patients with Glioma Grade 4 (GG4). The aim of the neuro-oncology section of the Italian Society of Neurosurgery (SINch®) was to provide a general overview of the current trends and technical tools to reach this goal. METHODS: A systematic review was performed. The results were divided and ordered, by an expert team of surgeons, to assess the Class of Evidence (CE) and Strength of Recommendation (SR) of perioperative drugs management, imaging, surgery, intraoperative imaging, estimation of EOR, surgery at tumor progression and surgery in elderly patients. RESULTS: A total of 352 studies were identified, including 299 retrospective studies and 53 reviews/meta-analysis. The use of Dexamethasone and the avoidance of prophylaxis with anti-seizure medications reached a CE I and SR A. A preoperative imaging standard protocol was defined with CE II and SR B and usefulness of an early postoperative MRI, with CE II and SR B. The EOR was defined the strongest independent risk factor for both OS and tumor recurrence with CE II and SR B. For intraoperative imaging only the use of 5-ALA reached a CE II and SR B. The estimation of EOR was established to be fundamental in planning postoperative adjuvant treatments with CE II and SR B and the stereotactic image-guided brain biopsy to be the procedure of choice when an extensive surgical resection is not feasible (CE II and SR B). CONCLUSIONS: A growing number of evidences evidence support the role of maximal safe resection as primary OS predictor in GG4 patients. The ongoing development of intraoperative techniques for a precise real-time identification of peritumoral functional pathways enables surgeons to maximize EOR minimizing the post-operative morbidity.

Minimally Invasive Surgery of Deep-Seated Brain Lesions Using Tubular Retractors and Navigated Transcranial Magnetic Stimulation-Based Diffusion Tensor Imaging Tractography Guidance: The Minefield Paradigm.

BACKGROUND: Surgical treatment of deep-seated brain lesions is a major challenge for neurosurgeons. Recently, tubular retractors have been used to help neurosurgeons in achieving the targeting and resection of deep lesions. OBJECTIVE: To describe a novel surgical approach based on the combination of tubular retractors and preoperative mapping by navigated transcranial magnetic stimulation (nTMS) and nTMS-based diffusion tensor imaging (DTI) tractography for the safe resection of deep-seated lesions. METHODS: Ten consecutive patients affected by deep-seated brain lesions close to eloquent motor/language/visual pathways underwent preoperative nTMS mapping of motor/language cortical areas and nTMS-based DTI tractography of adjacent eloquent white matter tracts, including optic radiations. The nTMS-based information was used to plan the optimal surgical trajectory and to guide the insertion of tubular retractors within the brain parenchyma without causing injury to the eloquent cortical and subcortical structures. After surgery, all patients underwent a new nTMS-based DTI tractography of fascicles close to the tumor to verify their structural integrity. RESULTS: Gross total resection was achieved in 8 cases, subtotal resection in 1 case, and a biopsy in 1 case. No new postoperative deficits were observed, except in 1 case where a visual field defect due to injury to the optic radiations occurred. Postoperative nTMS-based DTI tractography showed the integrity of the subcortical fascicles crossed by tubular retractors trajectory in 9 cases. CONCLUSION: The novel strategy combining tubular retractors with functional nTMS-based preoperative mapping enables a safe microsurgical resection of deep-seated lesions through the preservation of eloquent cortical areas and subcortical fascicles, thus reducing the risk of new permanent deficits.

The "Combo" radiotherapy treatment for high-risk grade 2 meningiomas: dose escalation and initial safety and efficacy analysis.

PURPOSE: The subgroup "high-risk" WHO grade 2 (hRG2) meningiomas may benefit from adjuvant radiation therapy (RT), but results are still suboptimal with high rates of local progression. A dose escalation using high-conformal RT techniques needs to be evaluated in terms of efficacy and safety. We report the results of a dose-escalation study, named "Combo-RT", combining Intensity Modulated Radiotherapy (IMRT) or Volumetric Arc Therapy (VMAT) with Hypofractionated Stereotactic Radiotherapy (hSRT) boost. PATIENTS AND METHODS: From November 2015 to January 2019, we prospectively enrolled 16 patients with hRG2. Seven patients had subtotal resection (STR) and 9 patients had a recurrent tumor. All patients received Combo-RT: LINAC-IMRT/ VMAT on the surgical bed and CyberKnife-hSRT boost on residual/recurrent meningioma Toxicity and initial efficacy were evaluated. RESULTS: The median age was 62 years (range, 31-80 years). The median cumulative dose delivered was 46 Gy For IMRT or VMAT and 15 Gy in 3 fractions at a median isodose line of 77% for hSRT. The median cumulative BED and EQD2 were 108.75 Gy and 72.5 Gy respectively. 3-year-PFS was 75% for the whole cohort,100% for patients with STR, and 55.5% for recurrent patients. Negligible toxicities, and stable or improved symptoms during long-term follow-up were observed. Salvage treatment for recurrence was an independent predictor of treatment failure (P = 0.025). CONCLUSIONS: With the limitation of a small series of patients, our results suggest that a dose escalation for hRG2 meningiomas, using a Combo-RT approach, is safe and particularly effective in the subgroup of patients with STR. Further studies are warranted.

Methylome Analysis in Nonfunctioning and GH-Secreting Pituitary Adenomas.

Pituitary adenomas (PAs), usually benign lesions, can sometimes present with "aggressive" features (rapid growth, local invasiveness, scarce response to conventional treatments). Despite the fact that a few genetic alterations have been associated to this clinical behavior, the role of epigenetic modifications, mainly methylation and miRNAs activity, is now opening new frontiers in this field. We evaluated the methylation profile of 21 PA (11 GH-omas, 10 nonfunctioning tumors-NFPAs) samples from TNS surgery and 5 normal pituitaries, collected at our neurosurgery between 2015 and 2017. DNA was extracted and sequenced, selecting 184,841 target regions. Moreover, methylation profiles were correlated with demographic, radiological, and clinicopathological features. NFPAs showed higher methylation levels vs. GH-omas, with 178 differentially methylated regions (DMRs) mainly consisting of noncoding and intronic sequences, and mostly localized in the open sea regions. We also found three hypermethylated genes (C7orf50, GNG7, and BAHCC1) involved in tumorigenesis processes and potentially influencing pituitary tumor pathophysiology. Among the clinicopathological features, only the maximum diameter resulted significantly higher in NFPAs. Our data provide further evidence of the complex epigenetic background of pituitary tumors. In line with the current literature, we confirmed a significant prevalence of hypermethylation in NFPAs vs. GH-omas, whose pathophysiological consequence is yet to be defined.

Cortical Excitability and Connectivity in Patients With Brain Tumors.

Background: Brain tumors can cause different changes in excitation and inhibition at the neuronal network level. These changes can be generated from mechanical and cellular alterations, often manifesting clinically as seizures. Objective/Hypothesis: The effects of brain tumors on cortical excitability (CE) have not yet been well-evaluated. The aim of the current study was to further investigate cortical-cortical and cortical-spinal excitability in patients with brain tumors using a more extensive transcranial magnetic stimulation protocol. Methods: We evaluated CE on 12 consecutive patients with lesions within or close to the precentral gyrus, as well as in the subcortical white matter motor pathways. We assessed resting and active motor threshold, short-latency intracortical inhibition (SICI), intracortical facilitation (ICF), short-latency afferent inhibition (SAI), long-latency afferent inhibition, cortical silent period, and interhemispheric inhibition. Results: CE was reduced in patients with brain tumors than in healthy controls. In addition, SICI, ICF, and SAI were lower in the affected hemisphere compared to the unaffected and healthy controls. Conclusions: CE is abnormal in hemispheres affected by brain tumors. Further studies are needed to determine if CE is related with motor impairment.

Endoscopic Endonasal Approach to the Ventral-Medial Portion of Posterior Paramedian Skull Base: A Morphometric Perspective of Surgical and Radiologic Anatomy.

OBJECTIVE: This study aims to provide morphometric analysis of endoscopic endonasal approach (EEA) to the ventral-medial portion of posterior paramedian skull base. Furthermore, it aims to investigate the surgical exposure obtained through EEA with and without eustachian tube (ET) removal, emphasizing the role of contralateral nostril (CN) access. METHODS: Five fresh adult head specimens were prepared for dissection. A predissection and a postdissection computed tomography study was performed. A surgically oriented classification into 4 regions was used: 1) tubercular region; 2) occipital condyle region; 3) parapharyngeal space (PPhS) region; and 4) jugular foramen (JF) region. The Student t-test was used to compare angulations and measures of EEA with access from the ipsilateral and CN, respectively, with and without ET removal. RESULTS: EEA to the ventral-medial portion of posterior paramedian skull base encompasses 2 medial trajectories (transtubercular and transcondylar) and 2 lateral pathways to the PPhS and JF. The CN access, without removal of the ET, allows a complete exposure of the petrous and intrajugular portion of the JF and superior PPhS without exposition of the parapharyngeal segment of internal carotid artery. The ipsilateral nostril approach with ET removal allows to obtain a wider exposure, reaching the medial sigmoid part of the JF. No significant differences exist in regard to transtubercular and transcondylar approaches. CONCLUSIONS: This study suggests that EEA to posterior paramedian skull base allows the realization of a corridor directed to the jugular tubercle, occipital condyle, medial PPhS, and ventral-medial JF. The CN approach with ET preservation can expose the petrous and intrajugular parts of the JF and PPhS. Case series are needed to demonstrate benefits and drawbacks of these approaches.

Clinical-Pathological, Immunohistochemical, and Genetic Characterization of a Series of Posterior Pituitary Tumors.

Posterior pituitary tumors are supposed to represent the morphological spectrum of a single entity. Herein, we report the clinical-pathological, immunohistochemical, and genetic features of 5 spindle cell oncocytomas (SCOs), 3 pituicytomas, and 1 granular cell tumor (GCT). SCOs had the highest local invasiveness and affected older subjects. The 3 histotypes differed in the content of spindle cells (predominant in pituicytoma and absent in GCT), presence of lymphocytic infiltrate (in SCO and GCT, but not in the pituicytoma) and EMA/GFAP staining (negative in GCT; EMA-positive/GFAP-negative in 4/5 SCO and GFAP-positive in 3/3 pituicytomas). Three SCOs and 1 pituicytoma analyzed with next-generation sequencing had no mutations in 409 genes. However, 1 SCO had previously unreported homozygous deletion of CDKN2A/B and another of SMARCA4, SMARCB1, and NF2. All 3 SCOs had loss of heterozygosity of chromosome 1p, while the pituicytoma had chromosome 19 homozygous loss and chromosomes 10, 13q, and 18q loss of heterozygosity. Since 1p and 13q losses were previously reported in 1 pituicytoma and 1 SCO, respectively, our data demonstrate that posterior pituitary tumors share common genetic alterations. The possibility that posterior pituitary tumors are SMARCA4/SMARCB1-deficient should be kept in mind in the differential diagnosis toward other entities.

Is age an additional factor in the treatment of elderly patients with glioblastoma? A new stratification model: an Italian Multicenter Study.

OBJECTIVE: Approximately half of glioblastoma (GBM) cases develop in geriatric patients, and this trend is destined to increase with the aging of the population. The optimal strategy for management of GBM in elderly patients remains controversial. The aim of this study was to assess the role of surgery in the elderly (≥ 65 years old) based on clinical, molecular, and imaging data routinely available in neurosurgical departments and to assess a prognostic survival score that could be helpful in stratifying the prognosis for elderly GBM patients. METHODS: Clinical, radiological, surgical, and molecular data were retrospectively analyzed in 322 patients with GBM from 9 neurosurgical centers. Univariate and multivariate analyses were performed to identify predictors of survival. A random forest approach (classification and regression tree [CART] analysis) was utilized to create the prognostic survival score. RESULTS: Survival analysis showed that overall survival (OS) was influenced by age as a continuous variable (p = 0.018), MGMT (p = 0.012), extent of resection (EOR; p = 0.002), and preoperative tumor growth pattern (evaluated with the preoperative T1/T2 MRI index; p = 0.002). CART analysis was used to create the prognostic survival score, forming six different survival groups on the basis of tumor volumetric, surgical, and molecular features. Terminal nodes with similar hazard ratios were grouped together to form a final diagram composed of five classes with different OSs (p < 0.0001). EOR was the most robust influencing factor in the algorithm hierarchy, while age appeared at the third node of the CART algorithm. The ability of the prognostic survival score to predict death was determined by a Harrell's c-index of 0.75 (95% CI 0.76-0.81). CONCLUSIONS: The CART algorithm provided a promising, thorough, and new clinical prognostic survival score for elderly surgical patients with GBM. The prognostic survival score can be useful to stratify survival risk in elderly GBM patients with different surgical, radiological, and molecular profiles, thus assisting physicians in daily clinical management. The preliminary model, however, requires validation with future prospective investigations. Practical recommendations for clinicians/surgeons would strengthen the quality of the study; e.g., surgery can be considered as a first therapeutic option in the workflow of elderly patients with GBM, especially when the preoperative estimated EOR is greater than 80%.

Coronavirus Disease 2019 (COVID-19) and Neurosurgery: Literature and Neurosurgical Societies Recommendations Update.

BACKGROUND: Since January 2020, when the pathogen causing the coronavirus disease was identified in humans, the literature on coronavirus disease 2019 (COVID-19) has grown exponentially to more than 4000 publications. There is the need to provide an update for each single medical discipline, including neurosurgery, to be used by single professionals or to be distributed through the neurosurgical community and to be used by governments in designing new scenario of care. METHODS: A review of the MEDLINE database was performed on April 13, 2020. Search terms included "COVID-19," "neurosurgery," and "surgery." A review of documents published on the webpage of the WFNS (World Federation of Neurosurgical Societies) and of the 5 continental associations of neurosurgical societies, AANS (American Association of Neurological Surgeons), AASNS (Asian Australasian Society of Neurological Surgeons), CAANS (Continental Association of African Neurosurgical Societies), EANS (European Association of Neurosurgical Societies), and FLANC (Latin American Federation of Neurosurgical Societies), representing the 119 national neurosurgical societies around the world, was performed. RESULTS: The literature search yielded 38 results that were manually reviewed. Fourteen manuscripts were considered eligible. They described suggestions and considerations to optimize care of neurosurgical patients, editorials on operational models, perspectives from neurosurgical departments, letters to the editor describing experiences on how to help medical staff to be prepared in advance for pandemic situations, and descriptions of regional or departmental models and/or organizational schemes. The webpages of the searched societies reported a total of 57 documents. CONCLUSIONS: The neurosurgical scientific community has promptly reacted to the COVID-19 outbreak by producing a growing number of documents that could serve as guidance for neurosurgeons all over the world. Neurosurgical societies will represent the key institutions for guiding the neurosurgical community to overcome the COVID-19 crisis.

Modern Treatment of Brain Arteriovenous Malformations Using Preoperative Planning Based on Navigated Transcranial Magnetic Stimulation: A Revisitation of the Concept of Eloquence.

BACKGROUND: Navigated transcranial magnetic stimulation (nTMS) provides a reliable identification of "eloquent" cortical brain areas. Moreover, it can be used for diffusion tensor imaging fiber tracking of eloquent subcortical tracts. We describe the use of nTMS-based cortical mapping and diffusion tensor imaging fiber tracking for defining the "eloquence" of areas surrounding brain arteriovenous malformations (BAVMs), aiming to improve patient stratification and treatment. METHODS: We collected data of BAVMs suspected to be in eloquent areas treated between 2017 and 2019, and submitted to nTMS-based reconstruction of motor, language, and visual pathways for the definition of the eloquence of the surrounding brain areas. We describe the nTMS-based approach and analyze its impact on patient stratification and allocation to treatment in comparison with the standard assessment of eloquence based on anatomical landmarks. RESULTS: Ten patients were included in the study. Preliminarily, 9 BAVMs were suspected to be located in an eloquent area. After nTMS-based mapping, only 5 BAVMs were confirmed to be close to eloquent structures, thus leading to a change of the score for eloquence and of the final BAVMs grading in 60% of patients. Treatment was customized according to nTMS information, and no cases of neurological worsening were observed. Radiological obliteration was complete in 7 cases microsurgically treated, and accounted for about 70% in the remaining 3 patients 1 year after radiosurgical treatment. CONCLUSIONS: The nTMS-based information allows an accurate stratification and allocation of patients with BAVMs to the most effective treatment according to a modern, customized, neurophysiological identification of the adjacent eloquent brain networks.

The role of navigated transcranial magnetic stimulation for surgery of motor-eloquent brain tumors: a systematic review and meta-analysis.

Navigated transcranial magnetic stimulation (nTMS) is an emerging tool for surgery of motor-eloquent intrinsic brain tumors, but a critical reappraisal of the literature evidence has never been performed, so far. A systematic review and meta-analysis was performed searching on PubMed/MEDLINE, and the Cochrane Central Register of Controlled Trials for studies that analyzed the impact of nTMS-based motor mapping on surgery of patients affected by motor-eloquent intrinsic brain tumors, in comparison with series of patients operated without using nTMS. The impact of nTMS mapping was assessed analyzing the occurrence of postoperative new permanent motor deficits, the gross total resection rate (GTR), the size of craniotomy and the length of surgery. Only eight studies were considered eligible and were included in the quantitative review and meta-analysis. The pooled analysis showed that nTMS motor mapping significantly reduced the risk of postoperative new permanent motor deficits (OR = 0.54, p = 0.001, data available from eight studies) and increased the GTR rate (OR = 2.32, p < 0.001, data from seven studies). Moreover, data from four studies documented the craniotomy size was reduced in the nTMS group (-6.24 cm2, p < 0.001), whereas a trend towards a reduction, even if non significant, was observed for the length of surgery (-10.30 min, p = 0.38) in three studies. Collectively, currently available literature provides data in favor of the use of nTMS motor mapping: its use seems to be associated with a reduced occurrence of postoperative permanent motor deficits, an increased GTR rate, and a tailored surgical approach compared to standard surgery without using preoperative nTMS mapping. Nonetheless, a growing need of high-level evidence about the use of nTMS motor mapping in brain tumor surgery is perceived. Well-designed randomized controlled studies from multiple Institutions are clearly advocated to continue to shed a light on this emerging topic.

Exoscope-Guided (VITOM 3D) Single-Stage Removal of Supratentorial Cavernous Angioma and Hemangioblastoma: 3-Dimensional Operative Video.

This video shows an exoscope-guided single-stage resection with 3-dimensional technology of a supratentorial cavernoma and a supratentorial hemangioblastoma during the same surgical procedure. The patient is a 42-yr-old man with a history of generalized tonico-clonic seizures. Contrast-enhanced magnetic resonance (MR) revealed the presence of a left frontal cavernoma and a left T1 non-enhancing hypointese temporal lesion (hemangioblastoma). The operation was carried out in the lateral position with the sole use of a 3D-exoscope (VITOM-3D, Karl Storz GmbH&Co, Tuttlingen, Germany). The operating room set-up included the surgeons standing at the head of the patients with the operating and navigator screens in the front of them and the exoscope arm entering from the left side. As recently highlighted, the 3D-exoscope carries several advantages: (1) it allows neurosurgeons to operate in a confortable and stable position; (2) it is less space-occupying in comparison to the microscope; (3) the optics and 3D-screen offer an optimal stereoscopic view in comparison to the 2D-exoscope, important for both surgical and training purposes; (4) although sharing with the endoscope, the image quality and confortable surgeon's position, there is no conflict between the surgical instruments and the scope in the surgical field. The adopted strategy enabled a complete resection of both lesions. The postoperative course was uneventful and the patient was seizure-free; the antiepileptic drugs were discontinued 3 mo after surgery. The 3D-exoscope represents a promising surgical tool, which may become part of the neurosurgical armamentarium. Nevertheless, the conceivable capability to improve neurosurgical results will have to be explored. All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards. The patient has consented to the submission of the surgical video for submission to the journal.

Endoscopic Endonasal Odontoidectomy and Posterior Fusion in a Single-Stage Surgery: Description of Surgical Technique and Outcome.

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