Transcranial Electrical Motor Evoked Potential Monitoring for Brain Tumor Resection

Zhou, Henry H.; Kelly, Patrick J.

doi:10.1227/00006123-200105000-00021

Cited by 38 publications

(54 citation statements)

References 32 publications

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“…14 Currently, it is acceptable that a persistent intraoperative MEP reduction of >50% is associated with postoperative motor deficits. 15,16 Cranial nerve paresis is usually an inevitable byproduct of treating MCF tumors. The oculomotor and trochlear nerves are the most vulnerable nerves resulting in this complication owing to the trajectory through the cavernous sinus and tentorial incisura.…”

Section: Discussionmentioning

confidence: 99%

Transzygomatic Approach with Intraoperative Neuromonitoring for Resection of Middle Cranial Fossa Tumors

et al. 2011

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Access to the floor of the middle cranial fossa (MCF) is often required when performing cranial base approaches to expose various lesions of the petrous apex, petroclival junction, internal auditory canal, and posterior cavernous sinus. In many patients with these lesions, a temporal craniotomy is sufficient to reach the floor of the MCF. However, the caudal limit of a simple temporal craniotomy is the zygomatic arch, which can present an obstacle in accessing the MCF in some individuals. Several authors have advocated mobilizing the zygomatic arch by performing a simple zygomatic osteotomy or using extended frontotemporo-orbitozygomatic approaches to reach low-lying lesions. [1][2][3] Intraoperative neuromonitoring (IOM) is one of the methods in which modern neurosurgery can improve surgical results while reducing morbidity. Motor-evoked potentials (MEPs) obtained by transcranial electrocortical stimulation is routinely used to monitor major motor pathways intraoperatively during several neurosurgical procedures. 4-6 Monitoring of oculomotor, trochlear, trigeminal, and facial nerve function is usually performed using free-running electromyography (EMG) or by direct stimulation of each cranial nerve. 7-9 Keywords ► middle fossa approach ► skull base surgery ► motor-evoked potentials ► intraoperative monitoring ► neurophysiology AbstractThe authors reviewed the surgical experience and operative technique in a series of 11 patients with middle fossa tumors who underwent surgery using the transzygomatic approach and intraoperative neuromonitoring (IOM) at a single institution. This approach was applied to trigeminal schwannomas (n ¼ 3), cavernous angiomas (n ¼ 3), sphenoid wing meningiomas (n ¼ 3), a petroclival meningioma (n ¼ 1), and a hemangiopericytoma (n ¼ 1). An osteotomy of the zygoma, a low-positioned frontotemporal craniotomy, removal of the remaining squamous temporal bone, and extradural drilling of the sphenoid wing made a flat trajectory to the skull base. Total resection was achieved in 9 of 11 patients. Significant motor pathway damage can be avoided using a change in motor-evoked potentials as an early warning sign. Four patients experienced cranial nerve palsies postoperatively, even though free-running electromyography of cranial nerves showed normal responses during the surgical procedure. A simple transzygomatic approach provides a wide surgical corridor for accessing the cavernous sinus, petrous apex, and subtemporal regions. Knowledge of the middle fossa structures is essential for anatomic orientation and avoiding injuries to neurovascular structures, although a neuronavigation system and IOM helps orient neurosurgeons.

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Section: Discussionmentioning

confidence: 99%

Transzygomatic Approach with Intraoperative Neuromonitoring for Resection of Middle Cranial Fossa Tumors

et al. 2011

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“…3,4,7,18,19,34,40,48,60 Intraoperative mapping and monitoring involving CMAPs is a valid modality for reducing iatrogenic morbidity during surgery in and around the central region as well as for intracranial aneurysms. 7,10,11,26,38,39,42,44,[49][50][51][52]62 Two methods are used for intraoperative mapping and monitoring during surgery in and around the insula. The first is the TCES of the motor cortex.…”

mentioning

confidence: 99%

Subcortical mapping and monitoring during insular tumor surgery

Kombos

Süss²,

Vajkoczy³

2009

FOC

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Object The treatment of insular tumors is controversial. Surgical treatment is associated with a higher morbidity rate than other therapies. The present work presents a new method in which the descending motor pathways are monitored during surgery for insular tumors. Methods Intraoperative monitoring was performed in a combination of 2 techniques. The motor cortex was stimulated with a transcranial electrical stimulus. In addition, direct subcortical stimulation was performed with an electrical anodal monopolar stimulus. Compound motor action potentials (CMAPs) were recorded from target muscles. Results Fifteen patients were included in this preliminary study. Following transcranial stimulation, CMAPs were recorded in all cases. Subcortical stimulation was successful in 12 cases. Significant CMAP alterations were recorded in 5 patients. There were no false-negative results in the series. Conclusions The technique presented here is a safe method. It allows a quantitative monitoring of motor function and functional mapping of the pyramidal tract during insular surgery.

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“…17) In the present case, the enhanced lesion was located in the cerebral peduncle, so MEPs were monitored following transcranial high-voltage stimulation together with direct peduncular stimulation. 12,26) Transcranial MEP seems to be the obvious candidate because stimulation evokes large and multiple descending motor volleys. 16) In our experience, high-voltage (600 V) stimulation can reach a deep site including the brain stem, whereas relatively low voltage (300-400 V) stimulation after craniotomy can be localized near the motor cortex.…”

Section: Discussionmentioning

confidence: 99%

Biopsy of Brain Stem Glioma Using Motor-Evoked Potential Mapping by Direct Peduncular Stimulation and Individual Adjuvant Therapy-Case Report-

Tanaka

Kobayashi

Utsuki

et al. 2005

Neurol. Med. Chir.(Tokyo)

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A 23-year-old man presented with a brain stem glioma manifesting as a 6-month history of right hemiparesis and diplopia. Serial magnetic resonance imaging showed an intrinsic diffuse brain stem glioma that gradually localized to the left cerebral peduncle after initial adjuvant therapy. Surgery was performed through a left subtemporal transtentorial approach under motor-evoked potential (MEP) mapping by direct peduncular stimulation. The lateral aspect of the midbrain was exposed, a train of five bipolar 25 mA pulses was applied, and MEPs recorded from the extremities. MEPs were only recorded from the left extremities even with left cerebral peduncular stimulation. Partial resection of the tumor was safely performed, with slight temporary neurological worsening. The histological diagnosis was anaplastic astrocytoma. Individual adjuvant therapy based on the results of real-time reverse transcription-polymerase chain reaction of O 6 -methylguanine-deoxyribonucleic acid methyltransferase achieved an almost complete tumor response. Surgery under pyramidal tract mapping and intensive postoperative adjuvant therapy resulted in a good outcome despite the presence of a generally intractable intrinsic brain stem glioma.

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Transcranial Electrical Motor Evoked Potential Monitoring for Brain Tumor Resection

Cited by 38 publications

References 32 publications

Transzygomatic Approach with Intraoperative Neuromonitoring for Resection of Middle Cranial Fossa Tumors

Transzygomatic Approach with Intraoperative Neuromonitoring for Resection of Middle Cranial Fossa Tumors

Subcortical mapping and monitoring during insular tumor surgery

Biopsy of Brain Stem Glioma Using Motor-Evoked Potential Mapping by Direct Peduncular Stimulation and Individual Adjuvant Therapy-Case Report-

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