Search

Standard of care in glioma surgery involves maximal-safe resection. Intraoperative stimulation mapping can improve the extent of resection in eloquent area tumors. Resection is performed during awake craniotomy (AC) or under general anesthesia (GA). Considering the advances in glioma management, an updated meta-analysis is needed. We identified studies evaluating surgical outcomes in adult patients undergoing glioma resection in motor areas, comparing AC and GA mapping until November 2023. Twenty-four observational studies and one randomized controlled trial met our inclusion criteria, adding 3011 patients. The mean extent of resection was 92.2% (95%CI = 89.9%-94.5%) for AC and 92.5% (95%CI = 89.6%-95.3%) for GA. Immediate deficit revealed a nonsignificant risk ratio (RR) of 0.96 favoring AC (95%CI = 0.66-1.41, p = 0.84). Similarly, long-term deficits showed a nonsignificant RR of 1.33 favoring GA (95%CI = 0.91-1.95, p = 0.14). Karnofsky performance score (KPS) analysis revealed a nonsignificant mean difference of 2.32 favoring GA (95%CI = -6.10-10.73, p = 0.59). Intraoperative stimulation-induced seizures analysis yielded a nonsignificant RR of 0.73 (95% CI = 0.27-1.97, p = 0.53) favoring AC. Postoperative seizure analysis showed a significant RR of 0.64 (95% CI = 0.44-0.94, p = 0.02) favoring AC. This meta-analysis suggests that AC and GA are comparable approaches to maximize extent of resection and achieve safe resection in eloquent glioma surgery. These findings can offer guidance to neurosurgeons in the decision-making process., Competing Interests: Declarations Ethics approval and consent to participate Not applicable. Consent for publication Not applicable. Competing interests The authors declare no competing interests., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

After resective glioma surgery in the Supplementary Motor Area (SMA), patients often experience a transient disturbance of the ability to initiate speech and voluntary motor actions, known as the SMA syndrome (SMAS). It has been proposed that enhanced interhemispheric functional connectivity (FC) within the sensorimotor system may serve as a potential mechanism for recovery, enabling the non-resected SMA to assume the function of the resected region. The purpose of the present study was to investigate the extent to which changes in FC can be observed in patients after resolution of the SMAS. Eight patients underwent resection of left SMA due to suspected gliomas, resulting in various levels of the SMA syndrome. Resting-state functional MR images were acquired prior to the surgery and after resolution of the syndrome. At the group level we found an increased connectivity between the unaffected (right) SMA and the primary motor cortex on the same side following surgery. However, no significant increase in interhemispheric connectivity was observed. These findings challenge the prevailing notion that increased interhemispheric FC serves as the only mechanism underlying recovery from SMA syndrome and suggest the presence of one or more alternative mechanisms., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Purpose: Brain plasticity after multistep surgery in low-grade glioma is highly variable; the neurosurgical approach must be individualised and functional imaging can be used for this purpose. In supplementary motor area complex (SMAC) tumors, the early and adequate functional recovery of patients raises the possibility of a latent bihemispheric or "mirror" cortico-subcortical network, which would develop depending on the needs of each patient., Methods: Functional and DTI-MR data from 4 right-handed patients with left frontal low grade gliomas near the SMAC, who were operated at least in two occasions were collected. The time of the reintervention was variable (18 months- 8 years), related to the tumor growth. All patients were evaluated by a neuropsychologist and imaged before each surgery, in a 3 T MR, with a 24 multichanel head coil Motor and expressive language task-fMRI and DTI sequences were obtained to evidence the main cortico-subcortical components of the SMAC. Data were processed with Brainwave (GE Medical Systems) and with an Iplan Fiber Tracking tool (MEDTRONIC), respectively RESULTS: None of our patients presented permanent neurological deficits after the first or second functional surgery. Three patients with partial or complete resection of the left middle and / or inferior frontal gyrus, and the left frontal aslant tract evidenced new right hemispherical cortical activity. This right shift were not observed in the patient without left middle gyrus resection, indeed with partial absent of the left frontal aslant tract., Conclusion: SMAC is a latent cortico-subcortical bihemispheric network that allows it to reorganize itself in response to specific neurological deficits. We highlight the importance in the cortical reorganization of the left middle frontal gyrus in the SMAC, closely connected with the essential language areas of this region, but also we focused in the potential cortioco-subcortical changes to compensate the functionality of the FAT., Competing Interests: Declaration of Competing Interest The authors have no relevant financial or non-financial interest to disclose., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Background: One of the challenges in surgery of tumors in motor eloquent areas is the individual risk assessment for postoperative motor disorder. Previously a regression model was developed that permits estimation of the risk prior to surgery based on topographical and neurophysiological data derived from investigation with nTMS (navigated Transcranial Magnetic Stimulation). This study aims to analyze the impact of including additional neurophysiological TMS parameters into the established risk stratification model for motor outcome after brain tumor surgery., Methods: Biometric and clinical data of 170 patients with glioma in motor eloquent areas were collected prospectively. In addition, the following nTMS parameters were collected bihemispherically prior to surgery: resting motor threshold (RMT), recruitment curve (RC), cortical silent period (CSP) and a nTMS based fibertracking to measure the tumor tract distance (TTD). Motor function was quantified by Medical Research Council Scale (MRCS) preoperatively, seven days and three months postoperatively. Association between nTMS parameters and postoperative motor outcome was investigated in bivariate and multivariable analyses., Results: The bivariate analysis confirmed the association of RMT ratio with the postoperative motor outcome after seven days with higher rates of worsening in patients with RMT ratio > 1.1 compared to patients with RMT ratio ≤ 1.1 (31.6% vs. 15.1%, p = 0.009). Similarly, an association between a pathological CSP ratio and a higher risk of new postoperative motor deficits after seven days was observed (35.3% vs. 16.7% worsening, p = 0.025). A pathological RC Ratio was associated postoperative deterioration of motor function after three months (42.9% vs. 16.2% worsening, p = 0.004). In multiple regression analysis, none of these associations were statistically robust., Conclusions: The current results suggest that the RC ratio, CSP ratio and RMT ratio individually are sensitive markers associated with the motor outcome 7 days and 3 months after tumor resection in a presumed motor eloquent location. They can therefore supply valuable information during preoperative risk-benefit-balancing. However, underlying neurophysiological mechanisms might be too similar to make the parameters meaningful in a combined model., (© 2024. The Author(s).)

Background: Navigated transcranial magnetic stimulation (nTMS) has been established as a preoperative diagnostic procedure in glioma surgery, increasing the extent of resection and preserving functional outcome. nTMS motor mapping for the resection of motor eloquent meningiomas has not been evaluated in a comparative analysis, yet., Methods: We conducted a retrospective matched-pair analysis for tumor location and size in meningioma patients with tumors located over or close to the primary motor cortex. Half of the study population received nTMS motor mapping preoperatively (nTMS-group). The primary endpoint were permanent surgery-related motor deficits. Additional factors associated with new motor deficits were evaluated apart from nTMS., Results: 62 patients (mean age 62 ± 15.8 years) were evaluated. 31 patients received preoperative nTMS motor mapping. In this group, motor thresholds (rMT) corresponded with tumor location and preoperative motor status, but could not predict motor outcome. No patient with preoperative intact motor function had a surgery-related permanent deficit in the nTMS group whereas four patients in the non-TMS group with preoperative intact motor status harbored from permanent deficits. 13 patients (21.3%) had a permanent motor deficit postoperatively with no difference between the nTMS and the non-TMS-group. Worsening in motor function was associated with higher patient age ( p  = 0.01) and contact to the superior sagittal sinus ( p = 0.027)., Conclusion: nTMSmotor mapping did not lead to postoperative preservation in motorfunction. nTMS data corresponded well with the preoperative motorstatus and were associated with postoperative permanent deficits if tumors were located over the motor hotspot according to nTMS.

Resection of a glioma from the dorsomedial frontal lobe, including the supplementary motor area (SMA), can result in postoperative SMA syndrome. SMA syndrome may occur during awake craniotomies. However, it is often difficult to intraoperatively distinguish between motor dysfunction due to pyramidal tract damage from that due to SMA syndrome. Patients with suspected intraoperative SMA syndrome are indifferent to their surroundings, have stiff facial muscles, and maintain a fixed gaze. We defined this condition as "apathetic look." The present study aimed to investigate whether intraoperative "apathetic look" is useful for identifying intraoperative SMA syndrome in patients with glioma close to motor-related areas, including the SMA, during awake craniotomy. This study included 33 consecutive patients with glioma included in the SMA. We excluded patients whose tumors extended to motor-related areas. We also assessed whether intraoperative SMA syndrome occurred in each patient. We evaluated the correlation between the occurrence of intraoperative SMA syndrome and various clinical factors, including intraoperative "apathetic look." Of the 33 patients, 12 had intraoperative SMA syndrome. Intraoperative "apathetic look" showed strong correlation with intraoperative SMA syndrome (p < 0.0001). Additionally, higher extent of resection (EOR) and resection of the corpus callosum showed a significantly higher incidence of intraoperative "apathetic look." All 12 patients with intraoperative SMA syndrome showed intraoperative "apathetic look" and recovered from SMA syndrome with high EOR. In conclusion, intraoperative "apathetic look" shows strong correlation with intraoperative SMA syndrome. Therefore, "apathetic look" may be a valuable indicator of intraoperative SMA syndrome during awake craniotomy., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Background: The balance between comprehensive intraoperative neurophysiological monitoring (IONM) for both upper and lower limbs while ensuring the reliability of motor evoked potentials (MEPs) is paramount in motor area surgery. It is commonly difficult to obtain good simultaneous stimulation of both upper and lower limbs. A series of factors can bias MEP accuracy, and inappropriate stimulation intensity can result in unreliable monitoring. The presented IONM technique is based on the concurrent use of both transcranial and cortical strip electrodes to facilitate simultaneous monitoring of both upper and lower limbs at optimized stimulation intensities to increase IONM accuracy during motor area surgery., Methods: Ten nonconsecutive motor area tumors were studied. Good visualization of both limbs was observed in the series at a low amperage (1.2 mA from the strip electrode and 165.3 mA from the transcranial electrode)., Results: Our analysis confirms concordance between the IONM data and postoperative outcomes. An MEP reduction >20% and >50% correlated with postoperative modified Rankin scale score changes without false-negative IONM findings., Conclusions: The technique was demonstrated to be accurate in providing a good simultaneous neurophysiological evaluation of both upper and lower limbs with an optimized and stimulation amplitude. The technique results in a low encumbrance of electrodes in the surgical field. Our results have confirmed the "proof of concept," its reliability and feasibility., (Copyright © 2024 Elsevier Inc. All rights reserved.)

This article addresses the discrepancy between Edouard Hitzig's and David Ferrier's findings on the cortical localization of movements in animals and Jean-Martin Charcot's findings in humans. The results of Hitzig's and Ferrier's vivisections were criticized by experimentalists in England and France as discordant, irreproducible, and inconclusive, and they were rejected by clinicians as irrelevant. Charcot addressed the gap between animal and human motor function by correlating motor deficits and focal epileptic seizures in patients to their autopsy findings. By this method he discovered the functional organization of the human motor cortex and produced the first accurate human motor brain map. Ferrier, William Osler, and Hughlings Jackson acknowledged Charcot's findings, and his findings guided the first neurosurgeons in localizing and resecting intracranial mass lesions presenting with focal epileptic seizures. Although his contributions in these fields have been neglected by modern historians, Charcot made significant contributions to the neurobiology of the human motor system, to epileptology, and to the birth of modern neurosurgery.

Background:  Resection of infiltrative neuroepithelial primary brain tumors, such as low-grade gliomas (LGGs) remains a neurosurgical challenge. Usual lack of clinical deficit despite LGGs growing in eloquent brain areas may be explained by reshaping and reorganization of functional networks. The development of modern diagnostic imaging techniques could disclose better understanding of the rearrangement of the brain cortex; however, mechanisms underlying such compensation and how it occurs in the motor cortex remain unclear. This systematic review aims to analyze the neuroplasticity of motor cortex in patients with LGGs, as determined by neuroimaging and functional techniques., Methods:  Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, medical subject headings (MeSH) and the following terms related to neuroimaging, LGGs and neuroplasticity were used with the Boolean operators AND and OR to synonymous terms in the PubMed database. Among the 118 results, 19 studies were included in the systematic review., Results:  Motor function in patients with LGG was characterized by a compensation in the contralateral and supplementary motor areas and premotor functional networks. Furthermore, ipsilateral activation in these types of gliomas was rarely described. Moreover, some studies did not reveal statistical significance in association between functional reorganization and the postoperative period, which can be explained by the low number of patients., Conclusion:  Our findings suggest a high pattern of reorganization per different eloquent motor areas and gliomas diagnosis. Understanding this process is useful to guide safe surgical resection and to develop protocols that assess the plasticity, even though functional network rearrangement needs to be better characterized by more studies., Competing Interests: None declared., (Thieme. All rights reserved.)

Objective: Anatomy and connections of the supplementary motor area (SMA) are studied essentially to analyze the SMA syndrome. Experience with surgical treatment of 19 tumors located in SMA is analyzed., Material and Methods: The cortical anatomy and subcortical connectivity of the SMA was studied on ten previously frozen and formalin fixed human cadaveric brain specimens. The white fiber dissection was performed using Klingler's method. Nineteen patients with low grade gliomas in the region of the SMA treated surgically were clinically analyzed., Results: The white fiber connections of the SMA include short arcuate connections with the pre-central, middle and inferior frontal gyri, the medial part of the SLF, the cingulum, the frontal aslant tract (FAT), the claustro-cortical fibers, the fronto-striatal tract and the crossed frontal aslant tract. All tumors were operated using en-masse surgical technique described by us and its subsequent modifications that focused on attempts towards preservation of related critical fiber tracts namely FAT, cingulum and corpus callosum presumed to be responsible for postoperative SMA syndrome. Eight patients developed an SMA syndrome in the immediate post-operative period. Eleven patients did not develop any post-operative neurological deficits. In all these 11 patients it was apparent that the cingulum, FAT and the corpus callosal fibers were preserved during surgery by modifying the tumor resection technique., Conclusions: SMA syndrome is a frequent occurrence following surgery in patients with tumors in the region of the SMA complex. Surgical strategy that preserves the cingulum and the FAT can prevent the occurrence of the SMA syndrome., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier Ltd.)

Objective: Establish the evolution of the connectome before and after resection of motor area glioma using a comparison of connectome maps and high-definition differential tractography (DifT)., Methods: DifT was done using normalized quantitative anisotropy (NQA) with DSI Studio. The quantitative analysis involved obtaining mean NQA and fractional anisotropy (FA) values for the disrupted pathways tracing the corticospinal tract (CST), and white fiber network changes over time., Results: We described the baseline tractography, DifT, and white matter network changes from two patients who underwent resection of an oligodendroglioma (Case 1) and an IDH mutant astrocytoma, grade 4 (Case 2)., Case 1: There was a slight decrease in the diffusion signal of the compromised CST in the immediate postop. The NQA and FA values increased at the 1-year follow-up (0.18 vs. 0.32 and 0.35 vs. 0.44, respectively)., Case 2: There was an important decrease in the immediate postop, followed by an increase in the follow-up. In the 1-year follow-up, the patient presented with radiation necrosis and tumor recurrence, increasing NQA from 0.18 in the preop to 0.29. Fiber network analysis: whole-brain connectome comparison demonstrated no significant changes in the immediate postop. However, in the 1-year follow up there was a notorious reorganization of the fibers in both cases, showing the decreased density of connections., Conclusions: Connectome studies and DifT constitute new potential tools to predict early reorganization changes in a patient's networks, showing the brain plasticity capacity, and helping to establish timelines for the progression of the tumor and treatment-induced changes., Competing Interests: Declaration of Competing Interest The authors have no conflict of interest to report., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Supplementary motor area syndrome (SMAS) represents a common neurosurgical sequela. The incidence and time frame of its occurrence have yet to be characterized after surgery for brain tumors. We examined patients suffering from a brain tumor preoperatively, postoperatively, and during follow-up examinations after three months, including fine motor skills testing and transcranial magnetic stimulation (TMS). 13 patients suffering from a tumor in the dorsal part of the superior frontal gyrus underwent preoperative, early postoperative, and 3-month follow-up testing of fine motor skills using the Jebsen-Taylor Hand Function Test (JHFT) and the Nine-Hole Peg Test (NHPT) consisting of 8 subtests for both upper extremities. They completed TMS for cortical motor function mapping. Test completion times (TCTs) were recorded and compared. No patient suffered from neurological deficits before surgery. On postoperative day one, we detected motor deficits in two patients, which remained clinically stable at a 3-month follow-up. Except for page-turning, every subtest indicated a significant worsening of function, reflected by longer TCTs (p < 0.05) in the postoperative examinations for the contralateral upper extremity (contralateral to the tumor manifestation). At 3-month follow-up examinations for the contralateral upper extremity, each subtest indicated significant worsening compared to the preoperative status despite improvement to the immediate postoperative level. We also detected significantly longer TCTs (p < 0.05) postoperatively in the ipsilateral upper extremity. This study suggests a long-term worsening of fine motor skills even three months after SMA tumor resection, indicating the necessity of targeted physical therapy for these patients., (© 2024. The Author(s).)

Background: Postoperative hemiparesis following frontal lobe lesion resection is alarming, and predicting motor function recovery is challenging. Supplementary motor area (SMA) syndrome following resection of frontal lobe lesions is often indistinguishable from postoperative motor deficit due to surgical injury of motor tracts. We aimed to describe the use of intraoperative transcranial electrical stimulation (TES) with motor evoked potential monitoring data as a diagnostic tool to distinguish between SMA syndrome and permanent motor deficit (PMD)., Methods: A retrospective analysis of 235 patients undergoing craniotomy and resection with TES-MEP monitoring for a frontal lobe lesion was performed. Patients who developed immediate postoperative motor deficit were included. Motor deficit and TES-MEP findings were categorized by muscle group as left upper extremity, left lower extremity, right upper extremity, or right lower extremity. Statistical analysis was performed to determine the predictive value of stable TES-MEP for SMA syndrome versus PMD., Results: This study included 20 patients comprising 29 cases of immediate postoperative motor deficit by muscle group. Of these, 27 cases resolved and were diagnosed as SMA syndrome, and 2 cases progressed to PMD. TES-MEP stability was significantly associated with diagnosis of SMA syndrome (P = 0.015). TES-MEP showed excellent diagnostic utility with a sensitivity and positive predictive value of 100% and 92.6%, respectively. Negative predictive value was 100%., Conclusions: Temporary SMA syndrome is difficult to distinguish from PMD immediately postoperatively. TES-MEP may be a useful intraoperative adjunct that may aid in distinguishing SMA syndrome from PMD secondary to surgical injury., (Copyright © 2024 Elsevier Inc. All rights reserved.)

The frontal aslant tract (FAT) connects the supplementary motor area (SMA) with the pars opercularis. Its role in language and its implications in glioma surgery remain under discussion. We present an anatomosurgical study of three cases with surgical resolution. Three patients with gliomas in the left frontal lobe were operated on using an awake patient protocol with cortical and subcortical mapping techniques, conducting motor and language evaluations. Tractography was performed using DSI Studio software. All three patients showed intraoperative language inhibition through subcortical stimulation of the FAT. Resection involving the FAT correlated with language deficits in all cases and movement initiation deficits in two cases. All patients recovered from their deficits at six months postoperatively. In conclusion, the tract has been successfully reconstructed, showing both anatomical and functional complexity, supporting the idea of its mapping and preservation in glioma surgery. Future interdisciplinary studies are necessary to determine the transient or permanent nature of the deficits.

Objective: This study aimed to evaluate the impact of augmented reality intraoperative fiber tractography (AR-iFT) on extent of resection (EOR), motor functional outcome, and survival of patients with primary motor area (M1) intra-axial malignant tumors., Methods: Data obtained from patients who underwent AR-iFT for M1 primary tumors were retrospectively analyzed and compared with those from a control group who underwent unaugmented reality intraoperative fiber tractography (unAR-iFT). A full asleep procedure with electrical stimulation mapping and fluorescein guidance was performed in both groups. The Neurological Assessment in Neuro-Oncology (NANO), Medical Research Council (MRC), and House-Brackmann grading systems were used for neurological, motor, and facial nerve assessment, respectively. Three-month postoperative NANO and MRC scores were used as outcome measures of the safety of the technique, whereas EOR and survival curves were related to its cytoreductive efficacy. In this study, p < 0.05 indicated statistical significance., Results: This study included 34 and 31 patients in the AR-iFT and unAR-iFT groups, respectively. The intraoperative seizure rate, 3-month postoperative NANO score, and 1-week and 1-month MRC scores were significantly (p < 0.05) different and in favor of the AR-iFT group. However, no difference was observed in the rate of complications. Glioma had incidence rates of 58.9% and 51.7% in the study and control groups, respectively, with no statistical difference. Metastasis had a slightly higher incidence rate in the control group, without statistical significance, and the gross-total resection and near-total resection rates and progression-free survival (PFS) rate were higher in the study group. Overall survival was not affected by the technique., Conclusions: AR-iFT proved to be feasible, effective, and safe during surgery for M1 tumors and positively affected the EOR, intraoperative seizure rate, motor outcome, and PFS. Integration with electrical stimulation mapping is critical to achieve constant anatomo-functional intraoperative feedback. The accuracy of AR-iFT is intrinsically limited by diffusion tensor-based techniques, parallax error, and fiber tract crowding. Further studies are warranted to definitively validate the benefits of augmented reality navigation in this surgical scenario.

Objective: In transcranial MR-guided focused ultrasound (TcMRgFUS), fiber tractography using diffusion tensor imaging (DTI) has been proposed as a direct method to identify the ventral intermediate nucleus (Vim), the ventral caudal nucleus (Vc), and the pyramidal tract (PT). However, the limitations of the DTI algorithm affect the accuracy of visualizing anatomical structures due to its low-quality fiber tractography, whereas the application of the generalized q-sampling imaging (GQI) algorithm enables the visualization of high-quality fiber tracts, offering detailed insights into the spatial distribution of motor cortex fibers. This retrospective study aimed to investigate the usefulness of high-precision fiber tractography using the GQI algorithm as a planning image in TcMRgFUS to achieve favorable clinical outcomes., Methods: This study included 20 patients who underwent TcMRgFUS. The Clinical Rating Scale for Tremor (CRST) scores and MR images were evaluated pretreatment and at 24 hours and 3-6 months after treatment. Cases were classified based on the presence and adversity of adverse events (AEs): no AEs, mild AEs without additional treatment, and severe AEs requiring prolonged hospitalization. Fiber tractography of the Vim, Vc, and PT was visualized using the DTI and GQI algorithm. The overlapping volume between Vim fibers and the lesion was measured, and correlation analysis was performed. The relationship between AEs and the overlapping volume of the Vc and PT fibers within the lesions was examined. The cutoff value to achieve a favorable clinical outcome and avoid AEs was determined using receiver operating characteristic curve analysis., Results: All patients showed improvement in tremors 24 hours after treatment, with 3 patients experiencing mild AEs and 1 patient experiencing severe AEs. At the 3- to 6-month follow-up, 5 patients experienced recurrence, and 2 patients had persistent mild AEs. Although fiber visualization in the motor cortex using the DTI algorithm was insufficient, the GQI algorithm enabled the visualization of significantly higher-quality fibers. A strong correlation was observed between the overlapping volume that intersects the lesion and Vim fibers and the degree of tremor improvement (r = 0.72). Higher overlapping volumes of Vc and PT within the lesion were associated with an increased likelihood of AEs (p < 0.05); the cutoff volume of Vim fibers within the lesion for a favorable clinical outcome was 401 mm3, while the volume of Vc and PT within the lesion to avoid AEs was 99 mm3., Conclusions: This pilot study suggests that incorporating the high-precision GQI algorithm for fiber tractography as a planning imaging technique for TcMRgFUS has the potential to enhance targeting precision and achieve favorable clinical outcomes.

Background: Motor cortex stimulation (MCS) represents a treatment option for refractory trigeminal neuralgia (TGN). Usually, patients need to be awake during surgery to confirm a correct position of the epidural electrode above the motor cortex, reducing patient's comfort., Method: Epidural cortical mapping (ECM) and motor evoked potentials (MEPs) were intraoperatively performed for correct localization of motor cortex under general anesthesia that provided comparable results to test stimulation after letting the patient to be awake during the operation., Conclusion: Intraoperative ECM and MEPs facilitate a confirmation of correct MCS-electrode position above the motor cortex allowing the MCS-procedure to be performed under general anesthesia., (© 2023. The Author(s).)

Competing Interests: None

Supplementary motor area (SMA) syndrome is characterised by transient disturbance in volitional movement and speech production which classically occurs after injury to the medial premotor area. We present two cases of SMA syndrome following isolated surgical injury to the frontal aslant tract (FAT) with the SMA intact. The first case occurred after resection of a left frontal operculum tumour. The second case occurred after a transcortical approach to a ventricular neurocytoma. The clinical picture and fMRI activation patterns during recovery were typical for SMA syndrome and support the theory that the FAT is a critical bundle in the SMA complex function., (© 2023. The Author(s).)

After surgical treatment of tumors of the supplementary motor area (SMA) post-operative speech and/or motor neurological deficit may occur., Objective: To determinate frequency and reversibility of such deficit and identify risk factors for its development., Material and Methods: We retrospectively analyzed postoperative outcomes in 34 patients with SMA tumors. Pre- and postoperative neurological status, localization of tumors, extent of resection relative to adjacent regions and relationship of tumor with white matter tracts were assessed. We also analyzed the influence of these factors on the risk of postoperative neurological impairment., Results: Postoperative neurological impairment occurred in 47% of cases. Complete or significant regression was observed in all patients within 5.7 month after surgery. Major risk factors were lesion of dominant hemisphere ( p =0.029), tumor spreading to primary motor cortex ( p =0.018) and resection of SMA together with cingulate gyrus ( p =0.000). Location of frontal aslant tract in dominant hemisphere just near the tumor contributed to disorders regarding speech initiation and fluency ( p =0.016). Resection of SMA with cingulate gyrus in dominant hemisphere affected development of more serious speech disorders ( p =0.003)., Conclusion: Surgery for SMA tumors is safe and followed by favorable functional outcomes.

Objective: Surgical resection of gliomas involving the supplementary motor area (SMA) frequently results in SMA syndrome, a symptom complex characterized by transient akinesia and mutism. Because the factors influencing patient functional outcomes after surgery remain elusive, the authors investigated network-based predictors in a multicentric cohort of glioma patients., Methods: The participants were 50 patients treated for glioma located in the SMA at one of the three centers participating in the study. Postoperative functional outcomes (motor deficits, mutism) and duration of symptoms were assessed during hospitalization. Long-term outcome was assessed 3 months after surgery. MRI-based lesion-symptom mapping was performed to estimate the severity of gray matter damage and white matter disconnection., Results: The median duration of acute symptoms was 3 days (range 1-42 days). Long-term deficits involving fine motor movements and speech were found at follow-up in 27 patients (54%). Disconnection of the central callosal fibers was associated with prolonged acute symptoms (p < 0.05). Postoperative mutism was significantly related to disconnection severity of the left frontopontine tract, frontal aslant tract, cingulum, and corticostriatal tract (p < 0.05). Disconnection of midposterior callosal fibers and lesion loads within the left medial Brodmann area 4 were associated with long-term motor deficits (p < 0.05)., Conclusions: This study provides evidence for the pathophysiology and predictive factors of postoperative SMA syndrome by demonstrating the relation of the disconnection of callosal fibers with prolonged symptom duration (central segment) and long-term motor deficits (midposterior segment). These data may be useful for presurgical risk assessment and adequate consultation for patients prior to undergoing resection of glioma located within the SMA region.

Objective: Drug-resistant essential tremor (ET) can be treated by Magnetic-Resonance-guided Focused-Ultrasound (MRgFUS) targeted to thalamic ventralis-intermediate nucleus (ViM). We are presenting the results obtained in ET patients by evaluating the cortico-muscular coherence (CMC) and the out-strength among cortical areas., Methods: We recorded MEG-EMG signals in 16 patients with predominant tremor on the right upper limb. The examination was performed the day before MRgFUS (T0) treatment, 24 hours (T1), and 3-months (T2) after lesioning the left ViM. Normalized CMC (nCMC) and cortico-cortical out-strength among cortical areas were assessed during isometric extension of the right hand., Results: According to the Essential Tremor Rating Assessment Scale, 13 of 16 patients were considered responders. At T1, in the beta-band, nCMC increased in the left hemisphere, namely in the areas directly involved in motor functions. At T2, the nCMC in non-motor areas decreased and the out-strength from other examined cortical areas toward the left motor-area decreased., Conclusions: In patients positively responding to MRgFUS, the CMC increased in the motor-area of the treated hemisphere immediately after the treatment, while the reorganization of CMC and cortico-cortical out-strength toward the cortical motor area occurred with a delay., Significance: The effective treatment with MRgFUS corresponds with a readjustment of the CMC and of the communication between cortical areas., (Copyright © 2022 International Federation of Clinical Neurophysiology. Published by Elsevier B.V. All rights reserved.)

Background: Previous studies have reported the pain-relieving effect of chronic electrical motor cortex stimulation (eMCS) in various types of neuropathic pain. The study aimed to explore the potential relationship between the clinical efficacy of eMCS for the treatment of chronic neuropathic pain and the precise localization of the contacts over the motor cortex somatotopic representation of the painful area., Methods: A total of 22 patients with neuropathic pain were implanted with eMCS electrodes. Implantation of the electrodes was performed using intraoperative 1) anatomical identification by neuronavigation software using 3D-MRI; 2) monitoring of somesthetic evoked potentials to check the potential reverse over the central sulcus; and 3) electrical stimulations through the dura to identify the motor responses and its somatotopy. Image fusion of postoperative 3D-CT and preoperative MRI images allowed postoperative location of the electrodes., Results: Analgesic effects were obtained in 18 (81.81%) out of 22 patients. Postoperative 3D-CT analysis showed a correspondence between localization of the contacts and the motor cerebral cortex somatotopy in the patients with postoperative good analgesic effects. No correspondence was found between localization of the contacts and the motor cerebral cortex somatotopy in the four patients with no analgesic effects. In three out of these four patients, analgesic effects were obtained after new surgery allowed repositioning of the electrode over the motor cortex somatotopy of the painful area., Conclusions: The findings of this study suggest that eMCS provides analgesic effects when the stimulated cortex corresponds to the somatotopy of the painful area.

Objective: To investigate the synergistic changes of the astrocytes and neurons in the sensorimotor cortex during the process of implant osseointegration after insertion., Methods: A total of 75 rats were allocated into three groups (n = 25): non-operated, extraction and implant. The rats in the latter two groups underwent extraction surgery of three maxillary right molars. One month later, the implant group received one titanium implant in the healed extraction socket. The rats were sacrificed on days 1, 3, 7, 14 and 28 after implantation. The brain sections, including sensory centre S1 and motor centre M1, were selected for further immunofluorescence for measurement of the synergistic morphological and quantitative changes of astrocytes and neurons., Results: In layer IV of S1, the number of astrocytes in the implant group showed a descending trend with time; on days 1, 3, 7 and 14, the number of astrocytes in both the extraction group and the implant group was significantly higher than that in the non-operated group, and there was no difference between the extraction group and the implant group; however, on day 28, the number of astrocytes in the implant group was significantly lower than that in the extraction group. In layer V of M1, on days 7, 14 and 28, the number of astrocytes in the implant group was significantly lower than that in the extraction group; on days 14 and 28, the number of astrocytes in the extraction group was significantly higher than that in the non-operated group. In layer IV of S1 or layer V of M1, the number of neurons showed no significant changes between the three groups., Conclusion: The astrocytes in the face sensorimotor cortex were activated as a reaction to oral environment changes. This kind of neuroplasticity can be reversed by oral rehabilitation with dental implants. The motor cortex may be intimately related to osseointegration and osseoperception.

Background: Supplementary motor area syndrome (SMAS) may occur after frontal tumor surgery, with variable presentation and outcomes. We reviewed the literature on postoperative SMAS after brain tumor resection., Methods: PubMed, Web of Science, Scopus, and Cochrane were searched following the PRISMA guidelines to include studies reporting SMAS after brain tumor resection., Results: We included 31 studies encompassing 236 patients. Most tumors were gliomas (94.5%), frequently of low grade (61.4%). Most lesions were located on the left hemisphere (64.4%), involving the supplementary motor area (61.4%) and the cingulate gyrus (20.8%). Tractography and functional magnetic resonance imaging evaluation were completed in 45 (19.1%) and 26 (11%) patients. Gross total resection was achieved in 46.3% patients and complete SMA resection in 69.4%. A total of 215 procedures (91.1%) used intraoperative neuromonitoring mostly consisting of direct cortical/subcortical stimulation (56.4%), motor (33.9%), and somatosensory (25.4%) evoked potentials. Postoperative SMAS symptoms occurred within 24 hours after surgery, characterized by motor deficits (97%), including paresis (68.6%) and hemiplegia (16.1%), and speech disorders (53%), including hesitancy (24.2%) and mutism (22%). Average SMAS duration was 45 days (range, 1-365 days), with total resolution occurring in 188 patients (79.7%) and partial improvement in 46 (19.5%). Forty-eight patients (20.3%) had persisting symptoms, mostly speech hesitancy (60.4%) and fine motor disorders (45.8%)., Conclusions: Postoperative SMAS may occur within the first 24 hours after mesial frontal tumor surgery. Preoperative mapping and intraoperative neuromonitoring may assist resection and predict outcomes. Neuroplasticity and interhemispheric connectivity play a major role in resolution., (Copyright © 2022 Elsevier Inc. All rights reserved.)

Background: Focal cortical dysplasia (FCD) is a common etiology of refractory epilepsy, particularly in children. Surgical management is potentially curative, but poses the challenge of distinguishing the border between ictogenic regions of dysplasia and functionally critical brain tissue. Bottom-of-a-sulcus dysplasia (BOSD) amplifies this challenge, due to difficulties in physiologic mapping of the deep tissue., Methods: We report a one-stage resection of a dysplasia-associated seizure focus abutting and involving the hand and face primary motor cortex. In doing so, we describe our surgical planning integrating neuronavigated transcranial magnetic stimulation (nTMS) for functional motor mapping, combined with intraoperative ultrasonography, intracranial electroencephalography, and magnetic resonance imaging (MRI). A 5-year-old girl with intractable focal epilepsy was referred to our comprehensive epilepsy program. Despite attentive pharmacotherapy, she experienced status epilepticus and up to 70 seizures per day, accompanied by multiple side effects from her antiseizure medication. A right frontal BOSD in close proximity to the hand motor area of the precentral gyrus was identified on MRI. Postoperatively, she is seizure-free for over 1 year with no hand deficit., Conclusion: Although technically complex, single-stage resection taking advantage of comprehensive surgical planning with optimized fusion of functional mapping and intraoperative modalities merits consideration given the invasiveness of a two-stage approach for limited added value. Integrated pre-surgical nTMS allowed for mapping of eloquent cortex without invasive electrocortical stimulation., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Objective: To investigate the brain mechanism of non-correspondence between diseases severity and compression degree of the spinal cord in cervical spondylotic myelopathy (CSM) patients and to test the utility of brain imaging biomarkers for predicting prognosis of CSM., Methods: We calculated voxel-wise zALFF from 54 CSM patients and 50 healthy controls using resting-state fMRI data. In analysis 1, we identified the brain regions exhibited significant differences of zALFF between CSM patients and healthy controls. In analyses 2 through 3, we investigated the zALFF differences between light-symptom CSM patients and severe-symptom CSM patients while carefully matching the degree of compression between these two groups. In analysis 4, we tested the utility of zALFF within the primary motor cortex (M1) for predicting the prognosis of CSM., Results: We found that (1) compared with the healthy controls, CSM patients exhibited higher ALFF within left M1, bilateral superior frontal gyrus, and lower zALFF within right precuneus and calcarine, suggesting altered brain neural activity in CSM patients; (2) after matching the compression degree, the CSM patients with more severe clinical symptoms exhibited higher zALFF within M1, indicating cortical function contributes to disease's severity of CSM; (3) taking the M1 zALFF as features in the prognosis prediction model improves the prediction accuracy, indicating that the M1 zALFF provide additional value for predicting the prognosis of CSM patients following decompression surgery., Conclusion: The functional state of M1 contributes to the disease's severity of CSM and can provide complementary information for predicting the prognosis of CSM following decompression surgery., Key Points: • Cervical spondylotic myelopathy (CSM) patients exhibited increased zALFF within the primary motor cortex (M1), bilateral superior frontal gyrus, and decreased zALFF within the right precuneus and calcarine. • After matching the compression degree, the CSM patients with more severe clinical symptoms exhibited higher zALFF within M1, indicating cortical function contributes to disease severity of CSM. • zALFF within M1 provided additional value for predicting the prognosis of CSM patients., (© 2022. The Author(s), under exclusive licence to European Society of Radiology.)

The supplementary motor area (SMA) syndrome is a frequently encountered clinical phenomenon associated with surgery of the dorsomedial prefrontal lobe. The region has a known motor sequencing function and the dominant pre-SMA specifically is associated with more complex language functions; the SMA is furthermore incorporated in the negative motor network. The SMA has a rich interconnectivity with other cortical regions and subcortical structures using the frontal aslant tract (FAT) and the frontostriatal tract (FST). The development of the SMA syndrome is positively correlated with the extent of resection of the SMA region, especially its medial side. This may be due to interruption of the nearby callosal association fibres as the contralateral SMA has a particular important function in brain plasticity after SMA surgery. The syndrome is characterized by a profound decrease in interhemispheric connectivity of the motor network hubs. Clinical improvement is related to increasing connectivity between the contralateral SMA region and the ipsilateral motor hubs. Overall, most patients know a full recovery of the SMA syndrome, however a minority of patients might continue to suffer from mild motor and speech dysfunction. Rarely, no recovery of neurological function after SMA region resection is reported., (© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Background: To avoid permanent neurologic deficits and preserve brain function, intraoperative electrical stimulation mapping (IESM) is essential for surgical resection., Case Report: A 59-year-old right-handed woman with ovarian cancer who had undergone stereotactic radiotherapy for brain metastasis two years before, was introduced due to progressive left upper paresis. Magnetic resonance imaging showed a recurrence of the lesion. We performed awake surgery using IESM. Thus, the sensorimotor site was elicited on the precentral and postcentral gyrus. However, IESM elicited no disturbance of motor function on the surface of the posterior part of the precentral gyrus. We made a safe corticotomy on it, and performed the resection of recurrent BM. Preserving the motor and sensory function, we achieved the resection of BM. After surgery, she experienced a significant improvement in motor function., Conclusion: IESM is a useful tool to make a safe approach via the precentral gyrus avoiding permanent sensorimotor deficits., (Copyright © 2022 International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.)

Objective: To analyze and compare the results of cerebral cortex mapping with task-based (tb-fMRI) and resting-state functional MRI in patients with glioma of eloquent cortical areas., Material and Methods: There were 55 patients (24 men and 31 women aged 24 - 74 years, median 39) with glial tumors. In 26 patients, the tumor was located in motor areas. Twenty-nine patients had lesions of Broca and Wernicke's areas. All patients underwent preoperative tb-fMRI and rs-fMRI. Then, resection of tumor was carried out in all cases., Results: Comparison of fMRI and rs-fMRI activation maps was assessed by calculating the Dice coefficient for inclusive speech and motor cortex masks and exclusive masks without brainstem, cerebellum, subcortical nuclei. Inclusive Dice coefficient for motor cortex ranged from 0.11 to 0.50, for speech cortex - from 0.006 to 0.240 ( p <0.05). In case of exclusive masks, this value ranged from 0.15 to 0.55 for motor cortex and from 0.004 to 0.205 for speech cortex ( p <0.05)., Conclusion: When comparing the results of cortical mapping in patients with glial tumors, the use of hemispheric exclusive and inclusive masks did not significantly increase activation maps matching. Probably, low degree of correspondence was associated with different genesis of activations, as well as with high variability of speech cortex.

Objective: The authors previously showed that combined evaluation of changes in intraoperative voluntary movement (IVM) during awake craniotomy and transcortical motor evoked potentials (MEPs) was useful for predicting postoperative motor function in 30 patients with precentral gyrus glioma. However, the validity of the previous report is limited to precentral gyrus gliomas. Therefore, the current study aimed to validate whether the combined findings of IVM during awake craniotomy and transcortical MEPs were useful for predicting postoperative motor function of patients with a glioma within or close to motor-related areas and not limited to the precentral gyrus., Methods: The authors included 95 patients with gliomas within or close to motor-related areas who were treated between April 2000 and May 2020. All tumors were resected with IVM monitoring during awake craniotomy and transcortical MEP monitoring. Postoperative motor function was classified into four categories: "no change" or "declined," the latter of which was further categorization as "mild," "moderate," or "severe." The authors defined moderate and severe deficits as those that impact daily life., Results: Motor function 6 months after surgery was classified as no change in 71 patients, mild in 18, moderate in 5, and severe in 1. Motor function at 6 months after surgery significantly correlated with IVM (p < 0.0001), transcortical MEPs (decline ≤ or > 50%) (p < 0.0001), age, preoperative motor dysfunction, extent of resection, and ischemic change on postoperative MRI. Thirty-two patients with no change in IVM showed no change in motor function at 6 months after surgery. Five of 34 patients (15%) with a decline in IVM and a decline in MEPs ≤ 50% had motor dysfunction with mild deficits 6 months after surgery. Furthermore, 19 of 23 patients (83%) with a decline in IVM and decline in MEPs > 50% had a decline in motor function, including 13 patients with mild, 5 with moderate, and 1 with severe deficits. Six patients with moderate or severe deficits had the lowest MEP values, at < 100 µV., Conclusions: This study validated the utility of combined application of IVM during awake craniotomy and transcortical MEP monitoring to predict motor function at 6 months after surgery in patients with a glioma within or close to motor-related areas, not limited to the precentral gyrus. The authors also validated the usefulness of the cutoff value, 100 µV, in MEP monitoring.

Objective: Surgical management of arteriovenous malformations (AVMs) involving motor cortex or fibre tracts (M-AVMs) is challenging. This study aimed to construct a classification system based on nidus locations and anterior choroidal artery (AChA) feeding to pre-surgically evaluate motor-related and seizure-related outcomes in patients undergoing resection of M-AVMs., Methods and Materials: A total of 125 patients who underwent microsurgical resection of M-AVMs were retrospectively reviewed. Four subtypes were identified based on nidus location: (I) nidus involving the premotor area and/or supplementary motor areas; (II) nidus involving the precentral gyrus; (III) nidus involving the corticospinal tract (CST) and superior to the posterior limb of the internal capsule; (IV) nidus involving the CST at or inferior to the level of posterior limb of the internal capsule. In addition, we divided type IV into type IVa and type IVb according to the AChA feeding. Surgical-related motor deficit (MD) evaluations were performed 1 week (short-term) and 6 months (long-term) after surgery., Results: The type I patients exhibited the highest incidence (62.0%) of pre-surgical epilepsy among the four subtypes. Multivariate analysis showed that motor-related area subtypes (p=0.004) and diffuse nidus (p=0.014) were significantly associated with long-term MDs. Long-term MDs were significantly less frequent in type I than in the other types. Type IV patients acquired the highest proportion (four patients, 25.0%) of long-term poor outcomes (mRS >2). Type IVb patients showed a significantly higher incidence of post-surgical MDs than type IVa patients (p=0.041). The MDs of type III or IV patients required more recovery time. Of the 62 patients who had pre-surgical seizures, 90.3% (56/62) controlled their seizures well and reached Engel class I after surgery., Conclusions: Combining the consideration of location and AChA feeding, the classification for M-AVMs is a useful approach for predicting post-surgical motor function and decision-making., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2021. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Background:  Resection of tumors adjacent to motor pathways carries risks of both postoperative motor deficit and incomplete resection. Our aim was to assess usefulness and limitations of a multimodal strategy that combines intraoperative ultrasound (iUS) guided resection with intraoperative neurophysiology., Methodology:  This is a prospective study of 25 patients with brain lesions adjacent to motor areas who underwent intracranial surgery with assistance of the iUS guidance system and intraoperative neurophysiological monitoring and mapping. Pathologies treated included 19 gliomas, 3 metastases, 1 anaplastic meningioma, 1 arteriovenous malformation (AVM), and 1 ependymoma. The iUS-guided lesion removal accuracy and the extent of resection were estimated and compared with a 30-day postoperative brain MRI. The results were assessed considering the extent of resection related to 6-month motor function outcome., Results:  iUS was accurate in checking the extent of resection in 17 patients, whereas in 8 cases the decline of the iUS images quality did not allow a valuable assessment. Positive mapping was obtained in 16 patients. Gross total resection was achieved in 16 patients. In five of nine cases with subtotal resection, surgery was stopped because a functional area was reached. In four patients, tumor removal was limited due to the difficulty of identifying neoplastic tissue. Motor function worsening was transient in six patients and permanent in two., Conclusions:  The integrated use of intraoperative neuromonitoring to identify motor areas and iUS to identify tumor-tissue interface could help increase the rate of radical resection respecting the eloquent areas., Competing Interests: None declared., (Thieme. All rights reserved.)

Background:  Lesions within the primary motor cortex (M1) and the corticospinal tract (CST) represent a significant surgical challenge with a delicate functional trade-off that should be integrated in the overall patient-centered treatment plan., Methods:  Patients with lesions within the M1 and CST with preoperative cortical and subcortical mapping (navigated transcranial magnetic stimulation [nTMS] and tractography), intraoperative mapping, and intraoperative provisional histologic information (smear with and without 5-aminolevulinic acid [5-ALA]) were included. This independently acquired information was integrated in a decision-making process model to determine the intraoperative extent of resection., Results:  A total of 10 patients (6 patients with metastatic precentral tumor; 1 patient with grade III and 2 patients with grade IV gliomas; 1 patient with precentral cavernoma) were included in the study. Most of the patients (60%) had a preoperative motor deficit. The nTMS documented M1 invasion in all cases, and in eight patients, the lesions were embedded within the CST. Overall, 70% of patients underwent gross total resection; 20% of patients underwent near-total resection of the lesions. In only one patient was no surgical resection possible after both preoperative and intraoperative mapping. Overall, 70% of patients remained stable postoperatively, and previous motor weakness improved in 20%., Conclusion:  The independently acquired anatomical (anatomical MRI) and functional (nTMS and tractography) tests in patients with CST lesions provide a useful guide for resection. The inclusion of histologic information (smear with or without 5-ALA) further allows the surgical team to balance the potential functional risks within the global treatment plan. Therefore, the patient is kept at the center of the informed decision-making process., Competing Interests: None declared., (Thieme. All rights reserved.)

Background:  The use of intraoperative monitoring (IOM) in glioma surgery is a widely adopted and clinically validated adjunct to define safe zones of resection for the neurosurgeon. However, the role of IOM in cases of a significant preexisting motor deficit is questionable., Case Description:  We describe a case of a 25-year-old with a recurrent presentation of a left paracentral glioblastoma, admitted with intratumoral hemorrhage and subsequent acute severe right-sided weakness. The patient underwent a redo left parietal craniotomy and 5-aminolevulinic acid-guided resection with IOM. The severity of the weakness was not reflected by the pre- and intraoperative cortical motor evoked potentials (MEPs) that were reassuring. The patient's hemiparesis recovered to full power postoperatively., Conclusions:  Preoperative weakness is traditionally accepted as a relative contraindication to IOM and therefore its usefulness is questioned in this context. Our case challenges this assumption. We present the clinical course, review the cranial and spinal literature including the reliability of IOM in cases of preoperative motor deficit, and discuss the need for tailor-made IOM strategies., Competing Interests: None declared., (Thieme. All rights reserved.)

Objective: Resection of glioma in the nondominant hemisphere involving the motor areas and pathways requires the use of brain-mapping techniques to spare essential sites subserving motor control. No clear indications are available for performing motor mapping under either awake or asleep conditions or for the best mapping paradigm (e.g., resting or active, high-frequency [HF] or low-frequency [LF] stimulation) that provides the best oncological and functional outcomes when tailored to the clinical context. This work aimed to identify clinical and imaging factors that influence surgical strategy (asleep motor mapping vs awake motor mapping) and that are associated with the best functional and oncological outcomes and to design a "motor mapping score" for guiding tumor resection in this area., Methods: The authors evaluated a retrospective series of patients with nondominant-hemisphere glioma-located or infiltrating within 2 cm anteriorly or posteriorly to the central sulcus and affecting the primary motor cortex, its fibers, and/or the praxis network-who underwent operations with asleep (HF monopolar probe) or awake (LF and HF probes) motor mapping. Clinical and imaging variables were used to design a motor mapping score. A prospective series of patients was used to validate this motor mapping score., Results: One hundred thirty-five patients were retrospectively analyzed: 69 underwent operations with asleep (HF stimulation) motor mapping, and 66 underwent awake (LF and HF stimulation and praxis task evaluation) motor mapping. Previous motor (strength) deficit, previous treatment (surgery/radiotherapy), tumor volume > 30 cm3, and tumor involvement of the praxis network (on MRI) were identified and used to design the mapping score. Motor deficit, previous treatment, and location within or close to the central sulcus favor use of asleep motor mapping; large tumor volume and involvement of the praxis network favor use of awake motor mapping. The motor mapping score was validated in a prospective series of 52 patients-35 underwent operations with awake motor mapping and 17 with asleep motor mapping on the basis of the score indications-who had a low rate of postoperative motor-praxis deficit (3%) and a high extent of resection (median 97%; complete resection in > 70% of patients)., Conclusions: Extensive resection of tumor involving the eloquent areas for motor control is feasible, and when an appropriate mapping strategy is applied, the incidence of postoperative motor-praxis deficit is low. Asleep (HF stimulation) motor mapping is preferable for lesions close to or involving the central sulcus and/or in patients with preoperative strength deficit and/or history of previous treatment. When a patient has no motor deficit or previous treatment and has a lesion (> 30 cm3) involving the praxis network, awake mapping is preferable.

Microendoscopic calcium imaging with one-photon miniature microscopes enables unprecedented readout of neural circuit dynamics during active behavior in rodents. In this study, we describe successful application of this technology in the rhesus macaque, demonstrating plug-and-play, head-mounted recordings of cellular-resolution calcium dynamics from large populations of neurons simultaneously in bilateral dorsal premotor cortices during performance of a naturalistic motor reach task. Imaging is stable over several months, allowing us to longitudinally track individual neurons and monitor their relationship to motor behavior over time. We observe neuronal calcium dynamics selective for reach direction, which we could use to decode the animal's trial-by-trial motor behavior. This work establishes head-mounted microendoscopic calcium imaging in macaques as a powerful approach for studying the neural circuit mechanisms underlying complex and clinically relevant behaviors, and it promises to greatly advance our understanding of human brain function, as well as its dysfunction in neurological disease., Competing Interests: Declaration of interests A.B., P.S.X., and J.J.N. are paid employees of Inscopix, Inc. The remaining authors declare no competing interests., (Copyright © 2021 The Author(s). Published by Elsevier Inc. All rights reserved.)

Background: Research suggests that unconscious activity in the supplementary motor area (SMA) precedes not only certain simple motor actions but also the point at which we become aware of our intention to perform such actions. The extent to which these findings have implications for our understanding of the concepts of free will and personal responsibility has been subject of intense debate during the latest four decades., Methods: This research is discussed in relation to effects of neurosurgical removal of the SMA in a narrative review., Results: Removal of the SMA typically causes a transient inability to perform non-stimulus-driven, voluntary actions. This condition, known as the SMA syndrome, does not appear to be associated with a loss of sense of volition but with a profound disruption of executive function/cognitive control., Conclusions: The role of the SMA may be to serve as a gateway between the corticospinal tract and systems for executive function. Such systems are typically seen as tools for conscious decisions. What is known about effects of SMA resections would thus seem to suggest a view that is compatible with concepts of personal responsibility. However, the philosophical question whether free will exists cannot be definitely resolved on the basis of these observations.

Background: Awake brain mapping paradigms are variable, particularly in SMA, and not personalised to each patient. In addition, subpial resections do not offer full protection to vascular injury, as the pia can be easily violated., Methods: Mapping paradigms developed by a multidisciplinary brain mapping team. During resection, a combined subpial/interhemispheric approach allowed early identification and arterial skeletonization. Precise anatomo-surgical dissection of the affected cingulum and corpus callosum was achieved., Conclusions: In SMA-cingulum-CC tumours, a combined subpial/interhemispheric approach reduces risk of vascular injury allowing precise anatomo-surgical dissections. Knowledge of cognitive functions of affected parcels is likely to offer best outcomes.

Background: Navigated transcranial magnetic stimulation (nTMS) is an established, noninvasive tool to preoperatively map the motor cortex. Despite encouraging reports from few academic centers with vast nTMS experience, its value for motor-eloquent brain surgery still requires further exploration., Objective: To further elucidate the role of preoperative nTMS in motor-eloquent brain surgery., Methods: Patients who underwent surgery for a motor-eloquent supratentorial glioma or metastasis guided by preoperative nTMS were retrospectively reviewed. The nTMS group (n = 105) was pair-matched to controls (non-nTMS group, n = 105). Gross total resection (GTR) and motor outcome were evaluated. Subgroup analyses including survival analysis for WHO III/IV glioma were performed., Results: GTR was significantly more frequently achieved in the entire nTMS group compared to the non-nTMS group (P = .02). Motor outcome did not differ (P = .344). Bootstrap analysis confirmed these findings. In the metastases subgroup, GTR rates and motor outcomes were equal. In the WHO III/IV glioma subgroup, however, GTR was achieved more frequently in the nTMS group (72.3%) compared to non-nTMS group (53.2%) (P = .049), whereas motor outcomes did not differ (P = .521). In multivariable Cox-regression analysis, prolonged survival in WHO III/IV glioma was significantly associated with achievement of GTR and younger patient age but not nTMS mapping., Conclusion: Preoperative nTMS improves GTR rates without jeopardizing neurological function. In WHO III/IV glioma surgery, nTMS increases GTR rates that might translate into a beneficial overall survival. The value of nTMS in the setting of a potential survival benefit remains to be determined., (Copyright © 2020 by the Congress of Neurological Surgeons.)

Resection of brain tumors involving motor areas and pathways requires the identification and preservation of various cortical and subcortical structures involved in motor control at the time of the procedure, in order to maintain the patient's full motor capacities. The use of brain mapping techniques has now been integrated into clinical practice for many years, as they help the surgeon to identify the neural structures involved in motor functions. A common definition of motor function, as well as knowledge of its neural organization, has been continuously evolving, underlining the need for implementing intraoperative strategies at the time of the procedure. Similarly, mapping strategies have been subjected to continuous changes, enhancing the likelihood of preservation of full motor capacities. As a general rule, the motor mapping strategy should be as flexible as possible and adapted strictly to the individual patient and clinical context of the tumor. In this work, we present an overview of current knowledge of motor organization, indications for motor mapping, available motor mapping, and monitoring strategies, as well as their advantages and limitations. The use of motor mapping improves resection and outcomes in patients harboring tumors involving motor areas and pathways, and should be considered the gold standard in the resection of this type of tumor., (Congress of Neurological Surgeons 2021.)