Intraoperative MRI–based elastic fusion for anatomically accurate tractography of the corticospinal tract: correlation with intraoperative neuromonitoring and clinical status

OBJECTIVETractography is a useful technique that is standardly applied to visualize subcortical pathways. However, brain shift hampers tractography use during the course of surgery. While intraoperative MRI (ioMRI) has been shown to be beneficial for use in oncology, intraoperative tractography can rarely be performed due to scanner, protocol, or head clamp limitations. Elastic fusion (EF), however, enables adjustment for brain shift of preoperative imaging and even tractography based on intraoperative images. The authors tested the hypothesis that adjustment of tractography by ioMRI-based EF (IBEF) correlates with the results of intraoperative neuromonitoring (IONM) and clinical outcome and is therefore a reliable method.METHODSIn 304 consecutive patients treated between June 2018 and March 2020, 8 patients, who made up the basic study cohort, showed an intraoperative loss of motor evoked potentials (MEPs) during motor-eloquent glioma resection for a subcortical lesion within the corticospinal tract (CST) as shown by ioMRI. The authors preoperatively visualized the CST using tractography. Also, IBEFs of pre- and intraoperative images were obtained and the location of the CST was compared in relation to a subcortical lesion. In 11 patients (8 patients with intraoperative loss of MEPs, one of whom also showed loss of MEPs on IBEF evaluation, plus 3 additional patients with loss of MEPs on IBEF evaluation), the authors examined the location of the CST by direct subcortical stimulation (DSCS). The authors defined the IONM results and the functional outcome data as ground truth for analysis.RESULTSThe maximum mean ± SD correction was 8.8 ± 2.9 (range 3.8–12.0) mm for the whole brain and 5.3 ± 2.4 (range 1.2–8.7) mm for the CST. The CST was located within the lesion before IBEF in 3 cases and after IBEF in all cases (p = 0.0256). All patients with intraoperative loss of MEPs suffered from surgery-related permanent motor deficits. By approximation, the location of the CST after IBEF could be verified by DSCS in 4 cases.CONCLUSIONSThe present study shows that tractography after IBEF accurately correlates with IONM and patient outcomes and thus demonstrates reliability in this initial study.

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Long-term motor deficit in brain tumour surgery with preserved intra-operative motor-evoked potentials

Brain Communications ◽

10.1093/braincomms/fcaa226 ◽

2021 ◽

Vol 3 (1) ◽

Author(s):

Davide Giampiccolo ◽

Cristiano Parisi ◽

Pietro Meneghelli ◽

Vincenzo Tramontano ◽

Federica Basaldella ◽

...

Keyword(s):

Evoked Potentials ◽

Brain Tumour ◽

Evoked Potential ◽

Corticospinal Tract ◽

Motor Evoked Potentials ◽

Motor Evoked Potential ◽

Motor Deficit ◽

Motor Deficits ◽

Brain Tumour Surgery

Abstract Muscle motor-evoked potentials are commonly monitored during brain tumour surgery in motor areas, as these are assumed to reflect the integrity of descending motor pathways, including the corticospinal tract. However, while the loss of muscle motor-evoked potentials at the end of surgery is associated with long-term motor deficits (muscle motor-evoked potential-related deficits), there is increasing evidence that motor deficit can occur despite no change in muscle motor-evoked potentials (muscle motor-evoked potential-unrelated deficits), particularly after surgery of non-primary regions involved in motor control. In this study, we aimed to investigate the incidence of muscle motor-evoked potential-unrelated deficits and to identify the associated brain regions. We retrospectively reviewed 125 consecutive patients who underwent surgery for peri-Rolandic lesions using intra-operative neurophysiological monitoring. Intraoperative changes in muscle motor-evoked potentials were correlated with motor outcome, assessed by the Medical Research Council scale. We performed voxel–lesion–symptom mapping to identify which resected regions were associated with short- and long-term muscle motor-evoked potential-associated motor deficits. Muscle motor-evoked potentials reductions significantly predicted long-term motor deficits. However, in more than half of the patients who experienced long-term deficits (12/22 patients), no muscle motor-evoked potential reduction was reported during surgery. Lesion analysis showed that muscle motor-evoked potential-related long-term motor deficits were associated with direct or ischaemic damage to the corticospinal tract, whereas muscle motor-evoked potential-unrelated deficits occurred when supplementary motor areas were resected in conjunction with dorsal premotor regions and the anterior cingulate. Our results indicate that long-term motor deficits unrelated to the corticospinal tract can occur more often than currently reported. As these deficits cannot be predicted by muscle motor-evoked potentials, a combination of awake and/or novel asleep techniques other than muscle motor-evoked potentials monitoring should be implemented.

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Ipsilateral Motor Innervation Discovered Incidentally on Intraoperative Monitoring: A Case Report

Neurosurgery ◽

10.1093/neuros/nyw074 ◽

2017 ◽

Vol 80 (3) ◽

pp. E194-E200

Author(s):

Jerry Ku ◽

Daniel Mendelsohn ◽

Jason Chew ◽

Jason Shewchuk ◽

Charles Dong ◽

...

Keyword(s):

Intraoperative Monitoring ◽

Corticospinal Tract ◽

Diffusion Tensor ◽

Motor Evoked Potentials ◽

Motor Deficits ◽

Motor Innervation ◽

First Case ◽

Technical Issues ◽

Cautious Interpretation ◽

Rare Anatomic Variant

Abstract BACKGROUND AND IMPORTANCE: Lesions in the corticospinal tract above the decussation at the medullary pyramids almost universally produce contralateral deficits. Rare cases of supratentorial lesions causing ipsilateral motor deficits have been reported previously, but only ever found secondary to stroke or congenital pyramidal tract malformations. CLINICAL PRESENTATION: Herein, we report a case of ipsilateral corticospinal tract innervation discovered incidentally with intraoperative monitoring during a microsurgical resection of a vestibular schwannoma. Intraoperative monitoring with electrical transcranial stimulation of the frontal scalp triggered motor-evoked potentials in the ipsilateral arms. The uncrossed pathways were later confirmed with MRI tractography using diffusion tensor imaging. CONCLUSION: To the best of our knowledge, this is the first case of isolated ipsilateral motor innervation of the corticospinal tract discovered incidentally during a neurosurgical procedure. Given the increasing use of intraoperative monitoring, this case underscores the importance of cautious interpretation of seemingly discordant neurophysiological findings. Once technical issues have been ruled out, ipsilateral motor innervation may be considered as a possible explanation and neurosurgeons should be aware of the existence of this rare anatomic variant.

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Management and outcomes of isolated interhemispheric subdural hematomas associated with falx syndrome

Journal of Neurosurgery ◽

10.3171/2018.8.jns181812 ◽

2019 ◽

Vol 131 (6) ◽

pp. 1920-1925

Author(s):

Daniel A. Tonetti ◽

William J. Ares ◽

David O. Okonkwo ◽

Paul A. Gardner

Keyword(s):

Neurological Deterioration ◽

Neurological Deficits ◽

Motor Deficits ◽

Study Cohort ◽

Venous Infarction ◽

Nonsurgical Management ◽

Subdural Hematomas ◽

Poor Outcomes ◽

Contemporary Management

OBJECTIVELarge interhemispheric subdural hematomas (iSDHs) causing falx syndrome are rare; therefore, a paucity of data exists regarding the outcomes of contemporary management of iSDH. There is a general consensus among neurosurgeons that large iSDHs with neurological deficits represent a particular treatment challenge with generally poor outcomes. Thus, radiological and clinical outcomes of surgical and nonsurgical management for iSDH bear further study, which is the aim of this report.METHODSA prospectively collected, single-institution trauma database was searched for patients with isolated traumatic iSDH causing falx syndrome in the period from January 2008 to January 2018. Information on demographic and radiological characteristics, serial neurological examinations, clinical and radiological outcomes, and posttreatment complications was collected and tallied. The authors subsequently dichotomized patients by management strategy to evaluate clinical outcome and 30-day survival.RESULTSTwenty-five patients (0.4% of those with intracranial injuries, 0.05% of those with trauma) with iSDH and falx syndrome represented the study cohort. The average age was 73.4 years, and most patients (23 [92%] of 25) were taking anticoagulants or antiplatelet medications. Six patients were managed nonoperatively, and 19 patients underwent craniotomy for iSDH evacuation; of the latter patients, 17 (89.5%) had improvement in or resolution of motor deficits postoperatively. There were no instances of venous infarction, reaccumulation, or infection after evacuation. In total, 9 (36%) of the 25 patients died within 30 days, including 6 (32%) of the 19 who had undergone craniotomy and 3 (50%) of the 6 who had been managed nonoperatively. Patients who died within 30 days were significantly more likely to experience in-hospital neurological deterioration prior to surgery (83% vs 15%, p = 0.0095) and to be comatose prior to surgery (100% vs 23%, p = 0.0031). The median modified Rankin Scale score of surgical patients who survived hospitalization (13 patients) was 1 at a mean follow-up of 22.1 months.CONCLUSIONSiSDHs associated with falx syndrome can be evacuated safely and effectively, and prompt surgical evacuation prior to neurological deterioration can improve outcomes. In this study, craniotomy for iSDH evacuation proved to be a low-risk strategy that was associated with generally good outcomes, though appropriately selected patients may fare well without evacuation.

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Neurophysiologic Mapping of Thalamocortical Tract in Asleep Craniotomies: Promising Results From an Early Experience

Operative Neurosurgery ◽

10.1093/ons/opaa330 ◽

2020 ◽

Author(s):

Mirela V Simon ◽

Daniel K Lee ◽

Bryan D Choi ◽

Pratik A Talati ◽

Jimmy C Yang ◽

...

Keyword(s):

General Anesthesia ◽

Corticospinal Tract ◽

Sensory Function ◽

Motor Deficit ◽

Motor Deficits ◽

Central Sulcus ◽

Postcentral Gyrus ◽

Subcortical Stimulation ◽

Subcortical Mapping

Abstract BACKGROUND Subcortical mapping of the corticospinal tract has been extensively used during craniotomies under general anesthesia to achieve maximal resection while avoiding postoperative motor deficits. To our knowledge, similar methods to map the thalamocortical tract (TCT) have not yet been developed. OBJECTIVE To describe a neurophysiologic technique for TCT identification in 2 patients who underwent resection of frontoparietal lesions. METHODS The central sulcus (CS) was identified using the somatosensory evoked potentials (SSEP) phase reversal technique. Furthermore, monitoring of the cortical postcentral N20 and precentral P22 potentials was performed during resection. Subcortical electrical stimulation in the resection cavity was done using the multipulse train (case #1) and Penfield (case #2) techniques. RESULTS Subcortical stimulation within the postcentral gyrus (case #1) and in depth of the CS (case #2), resulted in a sudden drop in amplitudes in N20 (case #1) and P22 (case #2), respectively. In both patients, the potentials promptly recovered once the stimulation was stopped. These results led to redirection of the surgical plane with avoidance of damage of thalamocortical input to the primary somatosensory (case #1) and motor regions (case #2). At the end of the resection, there were no significant changes in the median SSEP. Both patients had no new long-term postoperative sensory or motor deficit. CONCLUSION This method allows identification of TCT in craniotomies under general anesthesia. Such input is essential not only for preservation of sensory function but also for feedback modulation of motor activity.

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Increased corticospinal excitability prior to arm cycling is due to enhanced supraspinal but not spinal motoneurone excitability

Applied Physiology Nutrition and Metabolism ◽

10.1139/apnm-2013-0084 ◽

2013 ◽

Vol 38 (11) ◽

pp. 1154-1161 ◽

Cited By ~ 9

Author(s):

Kevin E. Power ◽

David B. Copithorne

Keyword(s):

Magnetic Stimulation ◽

Corticospinal Tract ◽

Biceps Brachii ◽

Motor Evoked Potentials ◽

Corticospinal Excitability ◽

Quiescent State ◽

M Wave ◽

Arm Cycling ◽

Intention To Move ◽

Stimulation Of

Human studies have not assessed supraspinal or spinal motoneurone excitability in the quiescent state prior to a rhythmic and alternating cyclical motor output. The purpose of the current study was to determine whether supraspinal and (or) spinal motoneurone excitability was modulated in humans prior to arm cycling when compared with rest with no intention to move. We hypothesized that corticospinal excitability would be enhanced prior to arm cycling due, in part, to increased spinal motoneurone excitability. Supraspinal and spinal motoneurone excitability were assessed via transcranial magnetic stimulation (TMS) of the motor cortex and transmastoid stimulation of the corticospinal tract, respectively. Surface electromyography recordings of TMS motor evoked potentials (MEPs) and cervicomedullary MEPs (CMEPs) were made from the relaxed biceps brachii muscle prior to rhythmic arm cycling and at rest with no intention to move. The amplitude of the MEPs was greater (mean increase: +9.8% of maximal M wave; p = 0.006) and their onset latencies were shorter (mean decrease: –1.5 ms; p < 0.05) prior to cycling when compared with rest. The amplitudes of the CMEPs at any of 3 stimulation intensities were not different between conditions. We conclude that premovement enhancement of corticospinal excitability is greater prior to arm cycling than at rest because of increases in supraspinal but not spinal motoneurone excitability.

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DIFFUSION MRI-BASED FIBER TRACKING IN HEALTHY AND BRAIN INJURY PATIENTS: A COMPARISON OF DIFFERENT SOFTWARE TOOLS

Journal of Mechanics in Medicine and Biology ◽

10.1142/s0219519415400205 ◽

2015 ◽

Vol 15 (02) ◽

pp. 1540020

Author(s):

GIULIA LUCCONI ◽

CHIARA ROMEO ◽

ROBERTO BONETTI ◽

PATRIZIA CENNI ◽

NICOLETTA SCRITTORI

Keyword(s):

Brain Injury ◽

Corpus Callosum ◽

Corticospinal Tract ◽

Preoperative Imaging ◽

Brain Images ◽

Non Invasive ◽

Imaging Tool ◽

Termination Criteria ◽

Fibers Orientation ◽

Deterministic And Probabilistic Approaches

In this work, we compared different DTI-based fibertracking software using deterministic and probabilistic approaches. DTI brain images of 35 healthy and five brain-injury patients were acquired with Philips Achieva 1.5 T scanner using an EPI-SE DTI sequence with 16 diffusion directions. Images were analyzed with Philips FiberTrack module, DTI-Studio and FSL. We studied corticospinal tract and corpus callosum, considering different termination criteria for the fibertracking algorithm. Group studies were performed to create a database of healthy patients. Results of FSL fibertracking with 1 or 2 fibers per voxel were no statistically different. T-tests between Philips and DTI-Studio led to p-values > 0.01 for corticospinal tract and < 0.01 for corpus callosum. FSL analysis led to higher ADC and lower FA values, with significative differences with the other software. In brain injury patients we measured different fibers orientation, reduced FA and increased ADC around the lesion. In conclusion, although DTI fibertracking is a promising non-invasive preoperative imaging tool, the outcome is strongly influenced by the algorithm used and the parameters chosen for the seed generation and fiber propagation.

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Abstract WP366: Quantitative Diffusion Tensor Tractography of the Corticospinal Tract as a Predictive Outcome Parameter in Patients With Intracerebral Hemorrhage

Stroke ◽

10.1161/str.48.suppl_1.wp366 ◽

2017 ◽

Vol 48 (suppl_1) ◽

Author(s):

Bastian Volbers ◽

Angelika Mennecke ◽

Nicola Kästle ◽

Hagen B Huttner ◽

Stefan Schwab ◽

...

Keyword(s):

Intracerebral Hemorrhage ◽

Corticospinal Tract ◽

Diffusion Tensor ◽

Clinical Status ◽

Internal Capsule ◽

Favorable Outcome ◽

Outcome Variable ◽

Cerebral Peduncle ◽

Prognostic Impact ◽

Posterior Limb

Introduction: Intracerebral hemorrhage (ICH) is a devastating disease with poor outcome. Established predictive markers include initial hematoma size, clinical status, intraventricular bleeding and age. However, prognostic assessment is often difficult which additionally burdens patients and caregivers and complicates rehabilitation. Functional outcome especially relies on motor function which is correlated with the integrity of the Corticospinal Tract (CST). Diffusion Tensor (DT) Tractography allows visualization of the CST. However, sufficient data about the prognostic impact of quantitative CST assessment is lacking. Methods: We prospectively enrolled patients with spontaneous supratentorial ICH admitted between 08/2012 und 08/2015. Informed consent and ethical approval was obtained. MRI scan was performed on day 5±1. DT data was normalized to MNI Space and Q-Space diffeomorphic reconstruction was performed using DSI-studio. CST was reconstructed based on quantitative anisotropy (QA) using the CST region (JHU white matter atlas) as seeding region and cerebral peduncle as region of interest (ROI). Fractional Anisotropy (FA) and QA were analyzed in the seeding and ROI region and in the posterior limb of the internal capsule (PLIC). Dichotomized modified Rankin Scale on day 90 (favorable outcome = mRS 0-2) was assessed as primary outcome variable. Results: 33 patients, mean age 70.7 y (standard deviation (SD) 12.9), 12 male, 21 with lobar hemorrhage, mean ICH volume on admission 16.5 (SD 11.3) cm 3 were included. 16 patients had a favorable outcome on day 90 (median mRS 3 (IQR 1-3.5). Mean number of reconstructed CST fiber pathways ipsilateral to ICH was higher in patients with favorable outcome (11343 (SD 8201)) than in patients with unfavorable outcome (4868 (SD 3221), p=0.008). Median QA and FA values in the PLIC ipsilateral to ICH were also higher in patients with favorable outcome (QA: 18.9 (IQR 16.2-23.3) vs. 14.6 (IQR 11.7 - 17.7), p=0.016, FA: 0.49 (IQR 0.45-0.53) vs. 0.41 (IQR 0.38-0.49), p=0.026). Conclusion: Higher FA- and QA-values in the PLIC and higher numbers of CST fiber pathways ipsilateral to ICH seem to be associated with a favorable outcome. DT Imaging may turn out as a useful quantitative predictive marker in the acute phase of ICH.

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Differential Recovery in Early- and Late-Onset Delayed Facial Palsy Following Vestibular Schwannoma Resection

Operative Neurosurgery ◽

10.1093/ons/opz083 ◽

2019 ◽

Vol 18 (1) ◽

pp. 34-40 ◽

Cited By ~ 2

Author(s):

Stephano Chang ◽

Serge Makarenko ◽

Ivan Despot ◽

Charles Dong ◽

Brian D Westerberg ◽

...

Keyword(s):

Facial Nerve ◽

Facial Palsy ◽

Early Onset ◽

Late Onset ◽

Motor Evoked Potentials ◽

Historical Analysis ◽

Study Cohort ◽

Postoperative Result ◽

Nerve Recovery ◽

Timing Of Onset

AbstractBACKGROUNDDelayed facial palsy (DFP) after resection of vestibular schwannomas (VS) is worsening of facial nerve function after an initially normal postoperative result.OBJECTIVETo characterize different types of DFP, compare recovery rates, and review of series of outcomes in patients following resection of VS.METHODSBetween 2001 and 2017, 434 patients (51% female) with VS underwent resection. We categorized the patients who developed facial palsy into groups based on timing of onset after surgery, immediate facial palsy (IFP), early-onset DFP (within 48 h), and late-onset DFP (after 48 h). Introduction of facial nerve motor-evoked potentials (fMEP) in 2002 and a change of practice utilizing perioperative minocycline in 2005 allowed for historical analysis of these interventions.RESULTSMean age of study cohort was 49.1 yr (range 13-81 yr), with 19.8% developing facial palsy. The late-onset DFP group demonstrated a significantly faster recovery than the early-onset DFP group (2.8 ± 0.5 vs 47 ± 8 wk, P < .0001), had prolonged latency to palsy onset after initiating perioperative minocycline (7.3 vs 12.5 d, P = .001), and had a nonsignificant trend towards faster recovery from facial palsy with use of minocycline (2.6 vs 3.4 wk, P = .11).CONCLUSIONGiven the timings, it is likely axonal degeneration is responsible for early-onset DFP, while demyelination and remyelination lead to faster facial nerve recovery in late-onset DFP. Reported anti-apoptotic properties of minocycline could account for the further delay in onset of DFP, and possibly reduce the rate and duration of DFP in the surgical cohort.

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Diabetes Mellitus-Related Dysfunction of the Motor System

International Journal of Molecular Sciences ◽

10.3390/ijms21207485 ◽

2020 ◽

Vol 21 (20) ◽

pp. 7485

Author(s):

Ken Muramatsu

Keyword(s):

Motor Control ◽

Motor Neurons ◽

Motor System ◽

Corticospinal Tract ◽

Experimental Studies ◽

Sensory System ◽

Treatment Strategies ◽

Motor Deficits ◽

New Perspective ◽

The Brain

Although motor deficits in humans with diabetic neuropathy have been extensively researched, its effect on the motor system is thought to be lesser than that on the sensory system. Therefore, motor deficits are considered to be only due to sensory and muscle impairment. However, recent clinical and experimental studies have revealed that the brain and spinal cord, which are involved in the motor control of voluntary movement, are also affected by diabetes. This review focuses on the most important systems for voluntary motor control, mainly the cortico-muscular pathways, such as corticospinal tract and spinal motor neuron abnormalities. Specifically, axonal damage characterized by the proximodistal phenotype occurs in the corticospinal tract and motor neurons with long axons, and the transmission of motor commands from the brain to the muscles is impaired. These findings provide a new perspective to explain motor deficits in humans with diabetes. Finally, pharmacological and non-pharmacological treatment strategies for these disorders are presented.

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Intraoperative vascular complications during 2278 cerebral endovascular procedures with multimodality IONM: relationship between signal change, complication, intervention and postoperative outcome

Journal of NeuroInterventional Surgery ◽

10.1136/neurintsurg-2020-016604 ◽

2020 ◽

pp. neurintsurg-2020-016604

Author(s):

W Bryan Wilent ◽

Olga Belyakina ◽

Eric Korsgaard ◽

Stavropoula I Tjoumakaris ◽

M Reid Gooch ◽

...

Keyword(s):

Endovascular Procedures ◽

Motor Evoked Potentials ◽

Vascular Complications ◽

Postoperative Outcome ◽

Complete Loss ◽

Motor Deficit ◽

Motor Deficits ◽

Likelihood Ratios ◽

Arterial Complication ◽

The Impact

BackgroundIntraoperative neuromonitoring (IONM) is often used during cerebral endovascular procedures.ObjectiveTo investigate the relationship between intraoperative vascular complications and IONM signal changes, and the impact of interventions on signal resolution and postoperative outcomes.MethodsA series of 2278 cerebral endovascular procedures conducted under general anesthesia and using electroencephalography and somatosensory evoked potential monitoring were retrospectively reviewed. A subset of 763 procedures also included motor evoked potentials (MEPs). IONM alerts were categorized as either a partial attenuation or complete loss of signal. Vascular complications were subcategorized as due to rupture, emboli, instrumentation, or vasospasm. Odds ratios (ORs) for new postoperative motor deficits were calculated and diagnostic accuracy was measured using sensitivity, specificity, and likelihood ratios.ResultsThe overall incidence of new postoperative motor deficit was 1.2%; 20.4% in cases with an IONM alert and 0.09% in cases without an alert. Relative to procedures with no alerts, odds of a new deficit increased if there was partial signal attenuation (OR=210.9, 95% CI 44.3 to 1003.5, p<0.0001) and increased further with complete loss of signal (OR=1437.3, 95% CI 297.3 to 6948.2, p<0.0001). Relative to procedures with unresolved alerts, odds of a new deficit decreased if the alert was fully resolved (OR=0.039, 95% CI 0.005 to 0.306, p<0.002). Procedures using MEPs had slightly higher sensitivity (92.3% vs 85.7%) but slightly lower specificity (96.7% vs 98.2%).ConclusionsAn IONM alert associated with an arterial complication is associated with a dramatic increase in odds of a new postoperative deficit; however, if there is resolution of the alert prior to closure, odds of a new deficit decrease significantly.

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