Long-Term Results of Stereotactic Radiotherapy in Patients with at Least 10 Brain Metastases at Diagnosis.

PURPOSE: to evaluate an SRT approach in patients with at least 10 lesions at the time of BM initial diagnosis. METHODS: This is a monocentric prospective cohort of patients treated by SRT, followed by a brain MRI every two months. Subsequent SRT could be delivered in cases of new BMs during follow-up. The main endpoints were local control rate (LCR), overall survival (OS), and strategy success rate (SSR). Acute and late toxicity were evaluated. RESULTS: Seventy patients were included from October 2014 to January 2019, and the most frequent primary diagnosis was non-small-cell lung cancer (N = 36, 51.4%). A total of 1174 BMs were treated at first treatment, corresponding to a median number of 14 BMs per patient. Most of the patients (N = 51, 72.6%) received a single fraction of 20-24 Gy. At 1 year, OS was 62.3%, with a median OS of 19.2 months, and SSR was 77.8%. A cumulative number of 1537 BM were treated over time, corresponding to a median cumulative number of 16 BM per patient. At 1-year, the LCR was 97.3%, with a cumulative incidence of radio-necrosis of 2.1% per lesion. Three patients (4.3%) presented Grade 2 toxicity, and there was no Grade ≥ 3 toxicity. The number of treated BMs and the treatment volume did not influence OS or SSR (p > 0.05). CONCLUSIONS: SRT was highly efficient in controlling the BM, with minimal side effects. In this setting, an SRT treatment should be proposed even in patients with ≥10 BMs at diagnosis.

Revitalizing neurosurgical frontiers: The EANS frontiers in neurosurgery committee's strategic framework.

Introduction: The field of neurosurgery faces challenges with the increasing involvement of other medical specialties in areas traditionally led by neurosurgeons. This paper examines the implications of this development for neurosurgical practice and patient care, with a focus on specialized areas like pain management, peripheral nerve surgery, and stereotactic radiosurgery. Research question: To assess the implications of the expanded scope of other specialties for neurosurgical practice and to consider the response of the EANS Frontiers in Neurosurgery Committee to these challenges. Materials and methods: Analysis of recent trends in neurosurgery, including the shift in various procedures to other specialties, demographic challenges, and the emergence of minimally invasive techniques. This analysis draws on relevant literature and the initiatives of the Frontiers in Neurosurgery Committee. Results: We explore a possible decrease in neurosurgical involvement in certain areas, which may have implications for patient care and access to specialized neurosurgical interventions. The Frontiers in Neurosurgery Committee's role in addressing these concerns is highlighted, particularly in terms of training, education, research, and networking for neurosurgeons, especially those early in their careers. Discussion and conclusion: The potential decrease in neurosurgical involvement in certain specialties warrants attention. This paper emphasizes the importance of carefully considered responses by neurosurgical societies, such as the EANS, to ensure neurosurgeons continue to play a vital role in managing neurological diseases. Emphasis on ongoing education, integration of minimally invasive techniques, and multidisciplinary collaboration is essential for maintaining the field's competence and quality in patient care.

Impact of biologically effective dose on tremor decrease after stereotactic radiosurgical thalamotomy for essential tremor: a retrospective longitudinal analysis.

Stereotactic radiosurgery (SRS) is one of the surgical alternatives for drug-resistant essential tremor (ET). Here, we aimed at evaluating whether biologically effective dose (BEDGy2.47) is relevant for tremor improvement after stereotactic radiosurgical thalamotomy in a population of patients treated with one (unplugged) isocenter and a uniform dose of 130 Gy. This is a retrospective longitudinal single center study. Seventy-eight consecutive patients were clinically analyzed. Mean age was 69.1 years (median 71, range 36-88). Mean follow-up period was 14 months (median 12, 3-36). Tremor improvement was assessed at 12 months after SRS using the ET rating assessment scale (TETRAS, continuous outcome) and binary (binary outcome). BED was defined for an alpha/beta of 2.47, based upon previous studies considering such a value for the normal brain. Mean BED was 4573.1 Gy2.47 (median 4612, 4022.1-4944.7). Mean beam-on time was 64.7 min (median 61.4; 46.8-98.5). There was a statically significant correlation between delta (follow-up minus baseline) in TETRAS (total) with BED (p = 0.04; beta coefficient - 0.029) and beam-on time (p = 0.03; beta coefficient 0.57) but also between TETRAS (ADL) with BED (p = 0.02; beta coefficient 0.038) and beam-on time (p = 0.01; beta coefficient 0.71). Fractional polynomial multivariate regression suggested that a BED > 4600 Gy2.47 and a beam-on time > 70 min did not further increase clinical efficacy (binary outcome). Adverse radiation events (ARE) were defined as larger MR signature on 1-year follow-up MRI and were present in 7 out of 78 (8.9%) cases, receiving a mean BED of 4650 Gy2.47 (median 4650, range 4466-4894). They were clinically relevant with transient hemiparesis in 5 (6.4%) patients, all with BED values higher than 4500 Gy2.47. Tremor improvement was correlated with BED Gy2.47 after SRS for drug-resistant ET. An optimal BED value for tremor improvement was 4300-4500 Gy2.47. ARE appeared for a BED of more than 4500 Gy2.47. Such finding should be validated in larger cohorts.

Dynamic functional changes upon thalamotomy in essential tremor depend on baseline brain morphometry.

Patients with drug-resistant essential tremor (ET) may undergo Gamma Knife stereotactic radiosurgical thalamotomy (SRS-T), where the ventro-intermediate nucleus of the thalamus (Vim) is lesioned by focused beams of gamma radiations to induce clinical improvement. Here, we studied SRS-T impacts on left Vim dynamic functional connectivity (dFC, n = 23 ET patients scanned before and 1 year after intervention), and on surface-based morphometric brain features (n = 34 patients, including those from dFC analysis). In matched healthy controls (HCs), three dFC states were extracted from resting-state functional MRI data. In ET patients, state 1 spatial stability increased upon SRS-T (F1,22 = 19.13, p = 0.004). More frequent expression of state 3 over state 1 before SRS-T correlated with greater clinical recovery in a way that depended on the MR signature volume (t6 = 4.6, p = 0.004). Lower pre-intervention spatial variability in state 3 expression also did (t6 = - 4.24, p = 0.005) and interacted with the presence of familial ET so that these patients improved less (t6 = 4.14, p = 0.006). ET morphometric profiles showed significantly lower similarity to HCs in 13 regions upon SRS-T (z ≤ - 3.66, p ≤ 0.022), and a joint analysis revealed that before thalamotomy, morphometric similarity and states 2/3 mean spatial similarity to HCs were anticorrelated, a relationship that disappeared upon SRS-T (z ≥ 4.39, p < 0.001). Our results show that left Vim functional dynamics directly relates to upper limb tremor lowering upon intervention, while morphometry instead has a supporting role in reshaping such dynamics.

Connectome-Based Neurosurgery in Primary Intra-Axial Neoplasms: Beyond the Traditional Modular Conception of Brain Architecture for the Preservation of Major Neurological Domains and Higher-Order Cognitive Functions.

Despite the therapeutical advancements in the surgical treatment of primary intra-axial neoplasms, which determined both a significative improvement in OS and QoL and a reduction in the incidence of surgery-induced major neurological deficits, nowadays patients continue to manifest subtle post-operative neurocognitive impairments, preventing them from a full reintegration back into social life and into the workforce. The birth of connectomics paved the way for a profound reappraisal of the traditional conception of brain architecture, in favour of a model based on large-scale structural and functional interactions of a complex mosaic of cortical areas organized in a fluid network interconnected by subcortical bundles. Thanks to these advancements, neurosurgery is facing a new era of connectome-based resections, in which the core principle is still represented by the achievement of an ideal onco-functional balance, but with a closer eye on whole-brain circuitry, which constitutes the foundations of both major neurological functions, to be intended as motricity; language and visuospatial function; and higher-order cognitive functions such as cognition, conation, emotion and adaptive behaviour. Indeed, the achievement of an ideal balance between the radicality of tumoral resection and the preservation, as far as possible, of the integrity of local and global brain networks stands as a mandatory goal to be fulfilled to allow patients to resume their previous life and to make neurosurgery tailored and gentler to their individual needs.

Impact of the Mean Cochlear Biologically Effective Dose on Hearing Preservation After Stereotactic Radiosurgery for Vestibular Schwannoma: A Retrospective Longitudinal Analysis.

BACKGROUND AND OBJECTIVES: Stereotactic radiosurgery (SRS) is a useful alternative for small- to medium-sized vestibular schwannoma. To evaluate whether biologically effective dose (BED Gy2.47 ), calculated for mean (BED Gy2.47 mean) and maximal (BED Gy2.47 max) cochlear dose, is relevant for hearing preservation. METHODS: This is a retrospective longitudinal single-center study. Were analyzed 213 patients with useful baseline hearing. Risk of hearing decline was assessed for Gardner-Robertson classes and pure tone average (PTA) loss. The mean follow-up period was 39 months (median 36, 6-84). RESULTS: Hearing decline (Gardner-Robertson class) 3 years after SRS was associated with higher cochlear BED Gy2.47 mean (odds ratio [OR] 1.39, P = .009). Moreover, BED Gy2.47 mean was more relevant as compared with BED Gy2.47 max (OR 1.13, P = .04). Risk of PTA loss (continuous outcome, follow-up minus baseline) was significantly corelated with BED Gy2.47 mean at 24 (beta coefficient 1.55, P = .002) and 36 (beta coefficient 2.01, P = .004) months after SRS. Risk of PTA loss (>20 dB vs ≤) was associated with higher BED Gy2.47 mean at 6 (OR 1.36, P = .002), 12 (OR 1.36, P = .007), and 36 (OR 1.37, P = .02) months. Risk of hearing decline at 36 months for the BED Gy2.47 mean of 7-8, 10, and 12 Gy 2.47 was 28%, 57%, and 85%, respectively. CONCLUSION: Cochlear BED Gy2.47 mean is relevant for hearing decline after SRS and more relevant as compared with BED Gy2.47 max. Three years after SRS, this was sustained for all hearing decline evaluation modalities. Our data suggest the BED Gy2.47 mean cut-off of ≤8 Gy 2.47 for better hearing preservation rates .

Clinically Driven Alpha/Beta Ratios for Melanoma Brain Metastases and Investigation of Biologically Effective Dose as a Predictor for Local Control After Radiosurgery: A Proof of Concept in a Retrospective Longitudinal Series of 274 Consecutive Lesions.

BACKGROUND AND OBJECTIVES: Brain metastases (BM) develop in nearly half of the patients with advanced melanoma. The aim of this retrospective historical cohort study was to analyze radiological response of melanoma BM to single-fraction Gamma Knife radiosurgery (GKRS), in relation to biologically effective dose (BED) for various alpha/beta ratios. METHODS: Included in the study were 274 lesions. Primary outcome was local control (LC). Mean marginal dose was 21.6 Gy (median 22, range 15-25). Biologically effective dose was calculated for an alpha/beta ratio of 3 (Gy 3 ), 5 (Gy 10 ), 10 (Gy 10 ), and 15 (Gy 15 ). RESULTS: Receiver operating characteristic value for LC and BED was 85% (most statistically significant odds ratio 1.14 for BED Gy 15 , P = .006), while for LC and physical dose was 79% ( P = .02). When comparing equality of 2 receiver operating characteristic areas, this was statistically significant ( P = .02 and .03). Fractional polynomial regression revealed BED (Gy 10 and Gy 15 ) as statistically significant ( P = .05) with BED of more than 63 Gy 10 or 49 Gy 15 as relevant, also for higher probability of quick decrease in volume first month after GKRS and lower probability of radiation necrosis. Shorter irradiation time was associated with better LC ( P = .001), particularly less than 40 minutes (LC below 90%, P = .05). CONCLUSION: BED Gy 10 and particularly Gy 15 were more statistically significant than physical dose for LC after GKRS for radioresistant melanoma BM. Irradiation time (per lesion) longer than 40 minutes was predictive for lower rates of LC. Such results need to be validated in larger cohorts.

Successful MRI-Guided Focused Ultrasound Thalamotomy after Ipsilateral Gamma Knife Radiosurgery for Essential Tremor: A Case Report with Video.

We report the case of a 67-year-old left-handed female patient with disabling medically refractory essential tremor who underwent successful right-sided magnetic resonance-guided focused ultrasound (MRgFUS) of the ventral intermediate nucleus after ipsilateral gamma knife radiosurgery (GKRS) thalamotomy performed 3 years earlier. The GKRS had a partial effect on her postural tremor without side effects, but there was no reduction of her kinetic tremor or improvement in her quality of life (QoL). The patient subsequently underwent a MRgFUS thalamotomy, which induced an immediate and marked reduction in both the postural and kinetic tremor components, with minor complications (left upper lip hypesthesia, dysmetria in her left hand, and slight gait ataxia). The MRgFUS-induced lesion was centered more medially than the GKRS-induced lesion and extended more posteriorly and inferiorly. The MRgFUS-induced lesion interrupted remaining fibers of the dentatorubrothalamic tract (DRTT). The functional improvement 1-year post-MRgFUS was significant due to a marked reduction of the patient's kinetic tremor. The QoL score (Quality of Life in Essential Tremor) improved by 88% and her Clinical Rating Scale for Tremor left hand score by 62%. The side effects persisted but were minor, with no impact on her QoL. The explanation for the superior efficacy of MRgFUS compared to GKRS in our patient could be due to either a poor response to the GKRS or to a better localization of the MRgFUS lesion with a more extensive interruption of DRTT fibers. In conclusion, MRgFUS can be a valuable therapeutic option after unsatisfactory GKRS, especially because MRgFUS has immediate clinical effectiveness, allowing intra-procedural test lesions and possible readjustment of the target if necessary.

Single fraction and hypofractionated radiosurgery for perioptic meningiomas-tumor control and visual outcomes: a systematic review and meta-analysis.

Perioptic meningiomas, defined as those that are less than 3 mm from the optic apparatus, are challenging to treat with stereotactic radiosurgery (SRS). Tumor control must be weighed against the risk of radiation-induced optic neuropathy (RION), as both tumor progression and RION can lead to visual decline. We performed a systematic review and meta-analysis of single fraction SRS and hypofractionated radiosurgery (hfRS) for perioptic meningiomas, evaluating tumor control and visual preservation rates. Using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, we reviewed articles published between 1968 and December 8, 2022. We retained 5 studies reporting 865 patients, 438 cases treated in single fraction, while 427 with hfRS. For single fraction SRS, the overall rate of tumor control was 95.1%, with actuarial rates at 5 and 10 years of 96% and 89%, respectively; tumor progression was 7.7%. The rate of visual stability was 90.4%, including visual improvement in 29.3%. The rate of visual decline was 9.6%, including blindness in 1.2%. For hfRS, the overall rate of tumor control was 95.6% (range 92.1-99.1, p < 0.001); tumor progression was 4.4% (range 0.9-7.9, p = 0.01). Overall rate of visual stability was 94.9% (range 90.9-98.9, p < 0.001), including visual improvement in 22.7% (range 5.0-40.3, p = 0.01); visual decline was 5.1% (range 1.1-9.1, p = 0.013). SRS is an effective and safe treatment option for perioptic meningiomas. Both hypofractionated regimens and single fraction SRS can be considered.

Single-fraction radiosurgery outcomes for large vestibular schwannomas in the upfront or post-surgical setting: a systematic review and International Stereotactic Radiosurgery Society (ISRS) Practice Guidelines.

PURPOSE: To perform a systematic review of literature specific to single-fraction stereotactic radiosurgery (SRS) for large vestibular schwannomas (VS), maximum diameter ≥ 2.5 cm and/or classified as Koos Grade IV, and to present consensus recommendations on behalf of the International Stereotactic Radiosurgery Society (ISRS). METHODS: The Medline and Embase databases were used to apply the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) approach. We considered eligible prospective and retrospective studies, written in the English language, reporting treatment outcomes for large VS; SRS for large post-operative tumors were analyzed in aggregate and separately. RESULTS: 19 of the 229 studies initially identified met the final inclusion criteria. Overall crude rate of tumor control was 89% (93.7% with no prior surgery vs 87.7% with prior surgery). Rates of salvage microsurgical resection, need for shunt, and additional SRS in all series versus those with no prior surgery were 9.6% vs 3.3%, 4.7% vs 6.4% and 1% vs 0.9%, respectively. Rates of facial palsy and hearing preservation in all series versus those with no prior surgery were 1.3% vs 3.4% and 34.2% vs 40.4%, respectively. CONCLUSIONS: Upfront SRS resulted in high rates of tumor control with acceptable rates of facial palsy and hearing preservation as compared to the results in those series including patients with prior surgery (level C evidence). Therefore, although large VS are considered classic indication for microsurgical resection, upfront SRS can be considered in selected patients and we recommend a prescribed marginal dose from 11 to 13 Gy (level C evidence).

Microsurgical resection of gliomas of the cingulate gyrus: a systematic review and meta-analysis.

Cingulate gyrus gliomas are rare among adult, hemispheric diffuse gliomas. Surgical reports are scarce. We performed a systematic review of the literature and meta-analysis, with the aim of focusing on the extent of resection (EOR), WHO grade, and morbidity and mortality, after microsurgical resection of gliomas of the cingulate gyrus. Using Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, we reviewed articles published between January 1996 and December 2022 and referenced in PubMed or Embase. Inclusion criteria were peer-reviewed clinical studies of microsurgical series reporting resection of gliomas of the cingulate gyrus. Primary outcome was EOR, classified as gross total (GTR) versus subtotal (STR) resection. Five studies reporting 295 patients were included. Overall GTR was 79.4% (range 64.1-94.7; I2= 88.13; p heterogeneity and p < 0.001), while STR was done in 20.6% (range 5.3-35.9; I2= 88.13; p heterogeneity < 0.001 and p= 0.008). The most common WHO grade was II, with an overall rate of 42.7% (24-61.5; I2= 90.9; p heterogeneity, p< 0.001). Postoperative SMA syndrome was seen in 18.6% of patients (10.4-26.8; I2= 70.8; p heterogeneity= 0.008, p< 0.001), postoperative motor deficit in 11% (3.9-18; I2= 18; p heterogeneity= 0.003, p= 0.002). This review found that while a GTR was achieved in a high number of patients with a cingulate glioma, nearly half of such patients have a postoperative deficit. This finding calls for a cautious approach in recommending and doing surgery for patients with cingulate gliomas and for consideration of new surgical and management approaches.

Proton beam radiation therapy for vestibular schwannomas-tumor control and hearing preservation rates: a systematic review and meta-analysis.

OBJECTIVE: Proton beam therapy is considered, by some authors, as having the advantage of delivering dose distributions more conformal to target compared with stereotactic radiosurgery (SRS). Here, we performed a systematic review and meta-analysis of proton beam for VSs, evaluating tumor control and cranial nerve preservation rates, particularly with regard to facial and hearing preservation. METHODS: We reviewed, using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) articles published between 1968 and September 30, 2022. We retained 8 studies reporting 587 patients. RESULTS: Overall rate of tumor control (both stability and decrease in volume) was 95.4% (range 93.5-97.2%, p heterogeneity= 0.77, p<0.001). Overall rate of tumor progression was 4.6% (range 2.8-6.5%, p heterogeneity < 0.77, p<0.001). Overall rate of trigeminal nerve preservation (absence of numbness) was 95.6% (range 93.5-97.7%, I2 = 11.44%, p heterogeneity= 0.34, p<0.001). Overall rate of facial nerve preservation was 93.7% (range 89.6-97.7%, I2 = 76.27%, p heterogeneity<0.001, p<0.001). Overall rate of hearing preservation was 40.6% (range 29.4-51.8%, I2 = 43.36%, p heterogeneity= 0.1, p<0.001). CONCLUSION: Proton beam therapy for VSs achieves high tumor control rates, as high as 95.4%. Facial rate preservation overall rates are 93%, which is lower compared to the most SRS series. Compared with most currently reported SRS techniques, proton beam radiation therapy for VSs does not offer an advantage for facial and hearing preservation compared to most of the currently reported SRS series.

Stereotactic Therapies for Meningiomas.

Although surgery remains the mainstay of treatment for most meningiomas, radiotherapy, specifically stereotactic radiosurgery, has become more commonplace as first-line therapy for select meningioma cases, particularly small meningiomas in challenging or high-risk anatomic locations. Radiosurgery for specific groups of meningiomas have been found to provide local control rates comparable to surgery alone. In this chapter stereotactic techniques for the treatment of meningiomas such as stereotactic radiosurgery by using Gamma knife or Linear Accelerator-based techniques (modified LINAC, Cyberknife, etc.) as well as stereotactically guided implantation or radioactive seeds for brachytherapy are introduced.

Resection of the contrast-enhancing tumor in diffuse gliomas bordering eloquent areas using electrophysiology and 5-ALA fluorescence: evaluation of resection rates and neurological outcome-a systematic review and meta-analysis.

Independently, both 5-aminolevulinic acid (5-ALA) and intraoperative neuromonitoring (IONM) have been shown to improve outcomes with high-grade gliomas (HGG). The interplay and overlap of both techniques are scarcely reported in the literature. We performed a systematic review and meta-analysis focusing on the concomitant use of 5-ALA and intraoperative mapping for HGG located within eloquent cortex. Using PRISMA guidelines, we reviewed articles published between May 2006 and December 2022 for patients with HGG in eloquent cortex who underwent microsurgical resection using intraoperative mapping and 5-ALA fluorescence guidance. Extent of resection was the primary outcome. The secondary outcome was new neurological deficit at day 1 after surgery and persistent at day 90 after surgery. Overall rate of complete resection of the enhancing tumor (CRET) was 73.3% (range: 61.9-84.8%, p < .001). Complete 5-ALA resection was performed in 62.4% (range: 28.1-96.7%, p < .001). Surgery was stopped due to mapping findings in 20.5% (range: 15.6-25.4%, p < .001). Neurological decline at day 1 after surgery was 29.2% (range: 9.8-48.5%, p = 0.003). Persistent neurological decline at day 90 after surgery was 4.6% (range: 0.4-8.7%, p = 0.03). Maximal safe resection guided by IONM and 5-ALA for high-grade gliomas in eloquent areas is achievable in a high percentage of cases (73.3% CRET and 62.4% complete 5-ALA resection). Persistent neurological decline at postoperative day 90 is as low as 4.6%. A balance between 5-ALA and IONM should be maintained for a better quality of life while maximizing oncological control.

Benefits of combined use of 68-Ga Dotatoc and 5-ALA fluorescence for recurrent atypical skull-base meningioma after previous microsurgery and Gamma Knife radiosurgery: a case report.

BACKGROUND: Studies of novel microsurgical adjuncts, such as 5-aminolevulinic acid (5-ALA) fluorescence have shown various fluorescence patterns within meningiomas, opening new avenues for complete microsurgical resection. Here, we present a recurrent, radiation-induced meningioma, previously operated on two occasions (initial gross total resection and subtotal 12 years later) and also irradiated by Gamma Knife radiosurgery (GKR, 6 years after the first surgery). We thought to assess the usefulness of 68-Ga Dotatoc in surgical target planning and of 5-ALA as an adjunct for maximal microsurgical excision. CASE REPORT: We report on a 43 years-old Caucasian male diagnosed with atypical, radiation induced WHO II meningioma, with left basal temporal bone implantation. Hodgkin lymphoma treated with cranial and mediastinal radiation during infancy marked his personal history. He underwent a first gross total microsurgical resection, followed 6 and 12 years later by Gamma Knife radiosurgery (GKR) and second subtotal microsurgical resection, respectively. Magnetic resonance imaging (MRI) displayed new recurrence 13 years after initial diagnosis. He was clinically asymptomatic but routine Magnetic resonance imaging showed constant progression. There was strong 68-Ga Dotatoc uptake. We used 5-ALA guided microsurgical resection. Intraoperative views confirmed strong fluorescence, in concordance with both preoperative Magnetic resonance imaging enhancement and 68-Ga Dotatoc. The tumor was completely removed, with meningeal and bone resection. CONCLUSION: The authors conclude that fluorescence-guided resection using 5-ALA is useful for recurrent atypical, radiation-induced meningioma even despite previous irradiation and multiple recurrences.

Combined use of intraoperative MRI and awake tailored microsurgical resection to respect functional neural networks: preliminary experience.

INTRODUCTION: The combined use of intraoperative MRI and awake surgery is a tailored microsurgical resection to respect functional neural networks (mainly the language and motor ones). Intraoperative MRI has been classically considered to increase the extent of resection for gliomas, thereby reducing neurological deficits. Herein, we evaluated the combined technique of awake microsurgical resection and intraoperative MRI for primary brain tumours (gliomas, metastasis) and epilepsy (cortical dysplasia, non-lesional, cavernomas). PATIENTS AND METHODS: Eighteen patients were treated with the commonly used "asleep awake asleep" (AAA) approach at Lille University Hospital, France, from November 2016 until May 2020. The exact anatomical location was insular with various extensions, frontal, temporal or fronto-temporal in 8 (44.4%), parietal in 3 (16.7%), fronto-opercular in 4 (22.2%), Rolandic in two (11.1%), and the supplementary motor area (SMA) in one (5.6%). RESULTS: The patients had a mean age of 38.4 years (median 37.1, range 20.8-66.9). The mean surgical duration was 4.1 hours (median 4.2, range 2.6-6.4) with a mean duration of intraoperative MRI of 28.8 minutes (median 25, range 13-55). Overall, 61% (11/18) of patients underwent further resection, while 39% had no additional resection after intraoperative MRI. The mean preoperative and postoperative tumour volumes of the primary brain tumours were 34.7 cc (median 10.7, range 0.534-130.25) and 3.5 cc (median 0.5, range 0-17.4), respectively. Moreover, the proportion of the initially resected tumour volume at the time of intraoperative MRI (expressed as 100% from preoperative volume) and the final resected tumour volume were statistically significant (p= 0.01, Mann-Whitney test). The tumour remnants were commonly found posterior (5/9) or anterior (2/9) insular and in proximity with the motor strip (1/9) or language areas (e.g. Broca, 1/9). Further resection was not required in seven patients because there were no remnants (3/7), cortical stimulation approaching eloquent areas (3/7) and non-lesional epilepsy (1/7). The mean overall follow-up period was 15.8 months (median 12, range 3-36). CONCLUSION: The intraoperative MRI and awake microsurgical resection approach is feasible with extensive planning and multidisciplinary collaboration, as these methods are complementary and synergic rather than competitive to improve patient oncological outcomes and quality of life.

How to combine the use of intraoperative magnetic resonance imaging (MRI) and awake craniotomy for microsurgical resection of hemorrhagic cavernous malformation in eloquent area: a case report.

BACKGROUND: Cavernous malformations are clusters of abnormal and hyalinized capillaries without interfering brain tissue. Here, we present a cavernous malformation operated under awake conditions, due to location, in an eloquent area and using intraoperative magnetic resonance imaging due to patient's movement upon the awake phase. CASE PRESENTATION: We present the pre-, per-, and postoperative course of an inferior parietal cavernous malformation, located in eloquent area, in a 27-year-old right-handed Caucasian male, presenting with intralesional hemorrhage and epilepsy. Preoperative diffusion tensor imaging has shown the cavernous malformation at the interface between the arcuate fasciculus and the inferior fronto-occipital fasciculus. We describe the microsurgical approach, combining preoperative diffusion tensor imaging, neuronavigation, awake microsurgical resection, and intraoperative magnetic resonance imaging. CONCLUSION: Complete microsurgical en bloc resection has been performed and is feasible even in eloquent locations. Intraoperative magnetic resonance imaging was considered an important adjunct, particularly used in this case as the patient moved during the "awake" phase of the surgery and thus neuronavigation was not accurate anymore. Postoperative course was marked by a unique, generalized seizure without any adverse event. Immediate and 3 months postoperative magnetic resonance imaging confirmed the absence of any residue. Pre- and postoperative neuropsychological exams were unremarkable.

Radiobiology of Radiosurgery for Neurosurgeons.

Stereotactic radiosurgery (SRS) is a precise focusing of radiation to a targeted point or larger area of tissue. With advances in technology, the radiobiological understanding of this modality has trailed behind. Although found effective in both short- and long-term follow-up, there are ongoing evolution and controversial topics such as dosing pattern, dose per fraction in hypo-fractionnated regimens, inter-fraction interval, and so on. Radiobiology of radiosurgery is not a mere extension of conventional fractionation radiotherapy, but it demands further evaluation of the dose calculation on the linear linear-quadratic model, which has also its limits, biologically effective dose, and radiosensitivity of the normal and target tissue. Further research is undergoing to understand this somewhat controversial topic of radiosurgery better.