Intra-operative subcortical electrical stimulation: A comparison of two methods

Szelényi, Andrea; Senft, Christian; Jardan, M.; Forster, Marie-Thérèse; Franz, Kea; Seifert, Volker; Vatter, Hartmuth

doi:10.1016/j.clinph.2010.12.055

Cited by 119 publications

(87 citation statements)

References 29 publications

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“…This MT corridor has been reported by several authors. 22,25,32,36,37,55 However, we also found that the critically low mapping MTs associated with motor deficit are probably lower than previously thought. In our experience, of the patients with a very low mapping MT of 1 mA, 75% showed stable DCS-MEP or only unspecific reversible changes, and none of them had a permanent motor worsening at 3 months.…”

Section: Is There a Safe Lower Mt?contrasting

confidence: 40%

Continuous dynamic mapping of the corticospinal tract during surgery of motor eloquent brain tumors: evaluation of a new method

Raabe¹,

Beck²,

Schucht³

et al. 2014

JNS

163

127

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Object The authors developed a new mapping technique to overcome the temporal and spatial limitations of classic subcortical mapping of the corticospinal tract (CST). The feasibility and safety of continuous (0.4–2 Hz) and dynamic (at the site of and synchronized with tissue resection) subcortical motor mapping was evaluated. Methods The authors prospectively studied 69 patients who underwent tumor surgery adjacent to the CST (< 1 cm using diffusion tensor imaging and fiber tracking) with simultaneous subcortical monopolar motor mapping (short train, interstimulus interval 4 msec, pulse duration 500 μsec) and a new acoustic motor evoked potential alarm. Continuous (temporal coverage) and dynamic (spatial coverage) mapping was technically realized by integrating the mapping probe at the tip of a new suction device, with the concept that this device will be in contact with the tissue where the resection is performed. Motor function was assessed 1 day after surgery, at discharge, and at 3 months. Results All procedures were technically successful. There was a 1:1 correlation of motor thresholds for stimulation sites simultaneously mapped with the new suction mapping device and the classic fingerstick probe (24 patients, 74 stimulation points; r2 = 0.98, p < 0.001). The lowest individual motor thresholds were as follows: > 20 mA, 7 patients; 11–20 mA, 13 patients; 6–10 mA, 8 patients; 4–5 mA, 17 patients; and 1–3 mA, 24 patients. At 3 months, 2 patients (3%) had a persistent postoperative motor deficit, both of which were caused by a vascular injury. No patient had a permanent motor deficit caused by a mechanical injury of the CST. Conclusions Continuous dynamic mapping was found to be a feasible and ergonomic technique for localizing the exact site of the CST and distance to the motor fibers. The acoustic feedback and the ability to stimulate the tissue continuously and exactly at the site of tissue removal improves the accuracy of mapping, especially at low (< 5 mA) stimulation intensities. This new technique may increase the safety of motor eloquent tumor surgery.

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Section: Is There a Safe Lower Mt?contrasting

confidence: 40%

Continuous dynamic mapping of the corticospinal tract during surgery of motor eloquent brain tumors: evaluation of a new method

Raabe¹,

Beck²,

Schucht³

et al. 2014

JNS

163

127

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show abstract

“…Some reports have used the 50-Hz stimulation technique, which was first described by Penfield in 1937; others have used the multipulse train stimulation technique ("train of five") first described by Taniguchi et al in 1993. 51 Stimulation conditions were also different with regard to bipolar versus monopolar stimulation, as well as stimulation polarity (anodal vs cathodal) and stimulation pulse duration. A report by Szelényi et al 49 compared different stimulation conditions in 20 patients. Both the multipulse train stimulation and the 50-Hz stimulation techniques, using bipolar or monopolar stimulation probes, were examined.…”

Section: Discussionmentioning

confidence: 99%

Intraoperative subcortical motor evoked potential stimulation: how close is the corticospinal tract?

Shiban¹,

Krieg²,

Haller

et al. 2015

JNS

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T he aim of surgery for primary and secondary intrinsic brain tumors is complete tumor resection to improve prognosis and control symptoms, and thereby improve the patient's quality of life. 24,39,45,47 However, the goal of maximum resection should be met without any new surgery-related neurological deficits arising, 13 and all efforts should be made to reduce patients' risk for neurological damage. Therefore, lesions in or near motor-eloquent regions, such as the precentral gyrus or the corticospinal tract (CST), represent particularly difficult situations in neurosurgery, and precautions need to be taken to prevent postoperative damage while maximizing resection.Intraoperative electrophysiological mapping and monitoring of the motor cortex and subcortical pyramidal tract obJect Subcortical stimulation is a method used to evaluate the distance from the stimulation site to the corticospinal tract (CST) and to decide whether the resection of an adjacent lesion should be terminated to prevent damage to the CST. However, the correlation between stimulation intensity and distance to the CST has not yet been clearly assessed. The objective of this study was to investigate the appropriate correlation between the subcortical stimulation pattern and the distance to the CST. methods Monopolar subcortical motor evoked potential (MEP) mapping was performed in addition to continuous MEP monitoring in 37 consecutive patients with lesions located in motor-eloquent locations. The proximity of the resection cavity to the CST was identified by subcortical MEP mapping. At the end of resection, the point at which an MEP response was still measurable with minimal subcortical MEP intensity was marked with a titanium clip. At this location, different stimulation paradigms were executed with cathodal or anodal stimulation at 0.3-, 0.5-, and 0.7-msec pulse durations. Postoperatively, the distance between the CST as defined by postoperative diffusion tensor imaging fiber tracking and the titanium clip was measured. The correlation between this distance and the subcortical MEP electrical charge was calculated. results Subcortical MEP mapping was successful in all patients. There were no new permanent motor deficits. Transient new postoperative motor deficits were observed in 14% (5/36) of cases. Gross-total resection was achieved in 75% (27/36) and subtotal resection (> 80% of tumor mass) in 25% (9/36) of cases. Stimulation intensity with various pulse durations as well as current intensity was plotted against the measured distance between the CST and the titanium clip on postoperative MRI using diffusion-weighted imaging fiberitracking tractography. Correlational and regression analyses showed a nonlinear correlation between stimulation intensity and the distance to the CST. Cathodal stimulation appeared better suited for subcortical stimulation. coNclusioNs Subcortical MEP mapping is an excellent intraoperative method to determine the distance to the CST during resection of motor-eloquent lesions and is highly capable of further reduc...

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“…76,83,88 Concerning this stimulation setup, Szelényi et al performed a highly cited and crucial study comparing train application with the single-pulse technique as well as bipolar and monopolar stimulation. 111 It was found that the CST is most efficiently identified using a multipulse train technique with a monopolar probe. Additionally, results of a large series of patients who underwent subcortical motor mapping were recently published, comparing the 60-Hz low-frequency technique to the train-of-five stimulation technique for subcortical motor mapping in patients with tumors involving the CST.…”

Section: Subcortical Mappingmentioning

confidence: 99%

Functional preoperative and intraoperative mapping and monitoring: increasing safety and efficacy in glioma surgery

Ottenhausen¹,

Krieg²,

Meyer³

et al. 2015

FOC

124

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Greater extent of resection (EOR) of low-grade gliomas is associated with improved survival. Proximity to eloquent cortical regions often limits resectability and elevates the risk of surgery-related deficits. Therefore, functional localization of eloquent cortex or subcortical fiber tracts can enhance the EOR and functional outcome. Imaging techniques such as functional MRI and diffusion tensor imaging fiber tracking, and neurophysiological methods like navigated transcranial magnetic stimulation and magnetoencephalography, make it possible to identify eloquent areas prior to resective surgery and to tailor indication and surgical approach but also to assess the surgical risk. Intraoperative monitoring with direct cortical stimulation and subcortical stimulation enables surgeons to preserve essential functional tissue during surgery. Through tailored pre- and intraoperative mapping and monitoring the EOR can be maximized, with reduced rates of surgery-related deficits.

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Intra-operative subcortical electrical stimulation: A comparison of two methods

Cited by 119 publications

References 29 publications

Continuous dynamic mapping of the corticospinal tract during surgery of motor eloquent brain tumors: evaluation of a new method

Continuous dynamic mapping of the corticospinal tract during surgery of motor eloquent brain tumors: evaluation of a new method

Intraoperative subcortical motor evoked potential stimulation: how close is the corticospinal tract?

Functional preoperative and intraoperative mapping and monitoring: increasing safety and efficacy in glioma surgery

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