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OBJECTIVE: To develop a more reliable methodology for monitoring the facial nerve in surgeries of vascular malformations where the extracranial segment of the nerve is at risk. METHODS: Our methodology comprises: (1) preoperative mapping to identify the anatomical location of the nerve branches, (2) continuous intraoperative monitoring of the compound muscle action potential (CMAP) by stimulating the facial nerve extracranially, in close proximity to where the trunk of the facial nerve exits the skull at the stylomastoid foramen, (3) intraoperative mapping to identify the nerve branches during surgical dissection and quantify the innervating contribution of each branch to the target muscle...

BACKGROUND: Navigated transcranial magnetic stimulation (nTMS) is increasingly used in presurgical brain mapping. Preoperative nTMS results correlate well with direct cortical stimulation (DCS) data in the identification of the primary motor cortex. Repetitive nTMS can also be used for mapping of speech-sensitive cortical areas. OBJECTIVE: The current cohort study compares the safety and effectiveness of preoperative nTMS with DCS mapping during awake surgery for the identification of language areas in patients with left-sided cerebral lesions...

The aim of the present study was to provide normative data for the Croatian language using 346 visually presented objects (Cycowicz, Friedman, Rothstein, & Snodgrass Journal of Experimental Child Psychology 65:171-237, 1997; Roach, Schwartz, Martin, Grewal, & Brecher Clinical Aphasiology 24:121-133, 1996; Snodgrass & Vanderwart Journal of Experimental Psychology: Human Learning and Memory 6:174-215, 1980). Picture naming was standardized according to seven variables: naming latency, name agreement, familiarity, visual complexity, word length, number of syllables, and word frequency...

OBJECTIVE: This study was to investigate the utility of motor evoked potential monitoring elicited by transcranial electrical stimulation (tcMEP) during CEA in addition to the established median nerve somatosensory evoked potentials (mSSEPs). METHODS: We retrospectively reviewed data from 600 patients undergoing CEA under general anesthesia with monitoring of mSSEPs and tcMEPs in a multicenter study. MSSEP and tcMEP parameters were recorded during internal carotid artery (ICA) cross clamping and compared with the postoperative motor outcome, demographic and patient history data...

No abstract text is available yet for this article.

OBJECTIVES: To establish a methodology for mapping of primary motor cortex (M1) for cricothyroid (CTHY) muscles in a group of healthy subjects using three-dimensional (3D) magnetic resonance imaging (MRI) navigated transcranial magnetic stimulation (nTMS). METHODS: Two independent measurements were performed. Twelve right-handed healthy subjects were included in the study. In the first measurement, mapping of the abductor pollicis brevis (APB) muscle was followed by mapping of the M1 for CTHY...

The cerebral metabolic and vascular effects of intravenous norepinephrine have been shown in an animal model using somatosensory-evoked potentials (SSEPs). A case of intravenous norepinephrine resulting in a decrease in SSEP amplitude (of greater than 50%) despite no significant change in blood pressure, prior to cross-clamping during a carotid endarterectomy is presented. This finding may have implications for the use of norepinephrine in the critical care unit as well as the operating room.

There is evidence that primary hemifacial spasm (HFS) in the majority of patients is related to a vascular compression of the facial nerve at its root exit zone (REZ). As a consequence, the hyperexcitability of facial nerve generates spasms of the facial muscles. Microvascular decompression (MVD) of the facial nerve near its REZ has been established as an effective treatment of HFS. Intra-operative disappearance of abnormal muscle responses (lateral spread) elicited by stimulating one of the facial nerve branches has been used as a method to predict MVD effectiveness...

OBJECT: Thoracic idiopathic spinal cord herniation (TISCH) is a rare neurological disorder characterized by an incarceration of the spinal cord at the site of a ventral dural defect. The disorder is associated with clinical signs of progressive thoracic myelopathy. Surgery can withhold the natural clinical course, but surgical repair of the dural defect bears a significant risk of additional postoperative motor deficits, including permanent paraplegia. Intraoperative online information about the functional integrity of the spinal cord and warning signs about acute functional impairment of motor pathways could contribute to a lower risk of permanent postoperative motor deficit...

Transcranial magnetic stimulation (TMS) is widely used both in basic research and in clinical practice. TMS has been utilized in studies of functional organization of speech in healthy volunteers. Navigated TMS (nTMS) allows preoperative mapping of the motor cortex for surgical planning. Recording behavioral responses to nTMS in the speech-related cortical network in a manner that allows off-line review of performance might increase utility of nTMS both for scientific and clinical purposes, e.g., for a careful preoperative planning...

OBJECTIVE: To establish the methodology for recording corticobulbar motor evoked potentials (CoMEPs) from cricothyroid muscles (CTHY) elicited by transcranial electrical (TES) and direct cortical stimulation (DCS). METHODS: Six healthy subjects and 18 patients undergoing brain surgery were included in the study. In six healthy subjects as well as in nine patients under general anaesthesia, CoMEP was obtained by TES. In three patients under general anaesthesia and in six patients during awake craniotomy, CoMEP was obtained by DCS...

No abstract text is available yet for this article.

Spinal dural arteriovenous malformation is an increasingly diagnosed cause of ischaemic myelopathy. Though routine intraoperative monitoring has been demonstrated to be of benefit in the endovascular treatment of these lesions, its predictive value has not been well documented. We present the case of an elderly woman with progressive spastic paraparesis who demonstrated marked improvement in limb muscle motor evoked potentials of the lower extremities immediately following endovascular occlusion of the lesion...

The purpose of this study is to evaluate efficacy and reliability of chemical provocative testing using neurophysiological monitoring prior to embolization of spinal cord AVMs (SCAVMs). We performed retrospective analysis of provocative testing using sodium amytal and lidocaine injected superselectively in 41 angiography and/or embolization procedures in 26 patients with a SCAVM, including 23 amytal and 26 lidocaine injections.All procedures were performed under general anesthesia using neuroleptic drugs, and with monitoring of cortical somatosensory evoked potentials (SEPs) and trans-cranial motor evoked potentials (MEPs)...

The decision whether or not to embolise during endovascular procedures for arteriovenous malformations (AVMs) of the spinal cord under general anesthesia, relies primarily on neurophysiological results of provocative tests with Lidocaine and short-acting barbiturates. Because of the complex haemodynamics of spinal AVMs, when either sensory (CSEPs) or muscle motor evoked potentials (mMEPs) are used independently, they can mislead the interpretation of provocative tests. This report illustrates the specific but complementary role played by provocative tests using CSEPs and mMEPs during embolisation of a low thoracic spinal cord AVM...

OBJECT: Intramedullary spinal cord tumors can displace the surrounding neural tissue, causing enlargement and distortion of the normal cord anatomy. Resection requires a midline myelotomy to avoid injury to the posterior columns. Locating the midline for myelotomy is often difficult because of the distorted anatomy. Standard anatomical landmarks may be misleading in patients with intramedullary spinal cord tumors due to cord rotation, edema, neovascularization, or local scar formation...

INTRODUCTION: New advancements of intraoperative neurophysiology for surgery in and around the brainstem have been described. NEUROPHYSIOLOGICAL TECHNIQUES: Brainstem mapping (BSM) is applied to locate cranial nerves and their motor nuclei (CMN) on the floor of the fourth ventricle. Corticobulbar tract (CBT) motor-evoked potential (MEP) monitoring is used to achieve on-line monitoring of the cranial motor nerves' functional integrity. DISCUSSION: Each of these procedures bears a specific role: BSM can help avoid direct damage to CMNs on the fourth ventricular floor; CBT-MEP can provide simultaneous feedback on the functional integrity of the CBT and CMN during surgery, eventually leading to "tailored" modifications of the surgical procedure, based upon neurophysiological responses...

PURPOSE: Intraoperative neurophysiological techniques are becoming routine tools for neurosurgical practice. Procedures affecting the lumbosacral nervous system are frequent in adult and pediatric neurosurgery. This review provides an overview of the techniques utilized in cauda and conus operations. METHODS: Two basic methodologies of intraoperative neurophysiological testing are utilized during surgery in the lumbosacral spinal canal. Mapping techniques help identify functional neural structures, namely, nerve roots and their respective spinal levels...

Until now, there have been no reports on eliciting the blink reflex (BR) during anesthesia at a depth compatible with surgery. We introduce a novel method for eliciting the R1 component of the BR under inhalation or total intravenous anesthesia by using a short train of four to seven stimuli applied over the supraorbital nerve. Recording is done from the ipsilateral orbicularis oculi muscle. We set out to record the BR in 27 patients (age 1-78 years) without involvement of the facial nerve, trigeminal nerve, or brainstem...

OBJECTIVE: To establish a methodology for recording corticobulbar motor evoked potentials (CoMEPs) from vocal muscles after transcranial electrical stimulation (TES) and direct cortical stimulation (DCS). METHODS: Twenty-four patients were included in this study (22 for TES, 2 for DCS, 3 for TES plus DCS) that underwent different surgical procedures. We used two methods to elicit CoMEPs: (a) TES by stimulation over C3/Cz or C4/Cz and (b) DCS with a strip electrode placed over the primary motor area (M1) for laryngeal muscles...