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Purpose: Previous evidence suggests that glioma re-resection can be effective in improving clinical outcomes. Furthermore, the use of mapping techniques during surgery has proven beneficial for newly diagnosed glioma patients. However, the effects of these mapping techniques during re-resection are not clear. This systematic review aimed to assess the evidence of using these techniques for recurrent glioma patients. Methods: A systematic search was performed to identify relevant studies. Articles were eligible if they included adult patients with recurrent gliomas (WHO grade 2–4) who underwent re-resection. Study characteristics, application of mapping, and surgical outcome data on survival, patient functioning, and complications were extracted. Results: The literature strategy identified 6372 articles, of which 125 were screened for eligibility. After full-text evaluation, 58 articles were included in this review, comprising 5311 patients with re-resection for glioma. Of these articles, 17% (10/58) reported the use of awake or asleep intraoperative mapping techniques during re-resection. Mapping was applied in 5% (280/5311) of all patients, and awake craniotomy was used in 3% (142/5311) of the patients. Conclusion: Mapping techniques can be used during re-resection, with some evidence that it is useful to improve clinical outcomes. However, there is a lack of high-quality support in the literature for using these techniques. The low number of studies reporting mapping techniques may, next to publication bias, reflect limited application in the recurrent setting. We advocate for future studies to determine their utility in reducing morbidity and increasing extent of resection, similar to their benefits in the primary setting. [ABSTRACT FROM AUTHOR]

Introduction: Understanding the spatiotemporal location of the spontaneous termination of ventricular tachycardia (VT) may provide new insights for ablation. To test the hypothesis that spontaneous VT termination most frequently occurs at the VT exit due to source‐sink mismatch and to characterize electrophysiological properties of the sites termination during VT and with extra‐stimulus technique. Methods: Retrospective analysis of intraoperative mapping studies of nine patients with ischemic cardiopathy or repaired tetralogy of Fallot. Simultaneous endocardial and epicardial mapping was performed in both ventricles using a custom mapping array during VT. Electrogram (EGM) characteristics before and at the moment of termination were analyzed including: cycle length oscillations, EGM heterogeneity and a variation in the systolic/diastolic path. The decrements to extra stimulus were analysed for termination sites and other diastolic sites. Results: Nine VTs in seven patients demonstrated spontaneous VT termination. Seven VTs (77.8%) spontaneously terminated in the final third of the systolic interval, one (11.1%) in early diastole and one (11.1%) in mid diastole. Cycle length oscillations (prolongation, shortening, and no change) were seen in equal frequency. Four VTs (44.4%) showed alternans in the local EGM at the site of termination and this was more prevalent than alternans at other sites in the diastolic pathway (p <.001). Only one‐third of VTs showed a change in activation pattern before termination. There was no difference based on etiology. During substrate characterization with extra‐stimulus pacing, sites of spontaneous termination showed greater decrement than other sites of the VT circuit during pacing (43.5 ± 14.5 ms vs. 31.2 ± 31.2 ms; p =.003). Conclusion: The entrance zone rather than the exit is the commonest site for the spontaneous termination of VT in the human heart. These sites tend to demonstrate EGM alternans during VT and greater decrement during extrastimulus pacing. These findings may help guide future studies into improving the success of VT ablation. [ABSTRACT FROM AUTHOR]

Intraoperative mapping of the nervous system is used to identify "eloquent" cortical areas. In this technical report, we describe a novel way of mapping the somatosensory cortex so that injury to those critical pathways can be avoided. An 8-year-old female with drug resistant epilepsy presented for resection of a right posterior parietal focal cortical dysplasia. Left median nerve stimulation was used to record somatosensory evoked potentials (SEPs) directly from the somatosensory cortex with a strip electrode. A handheld monopolar electrode was also used to record both the median and tibial SEP. Total intravenous anesthesia with propofol and remifentanil was used. SEP recordings were obtained from a 4-contact strip electrode placed across the central sulcus. A phase reversal was identified and the most likely post central gyrus was noted. With the strip electrode left in place, a monopolar handheld electrode was used to record the median nerve SEPs from different locations on the postcentral gyrus. The tibial nerve was also stimulated to record where the highest amplitude tibial nerve SEP was present. This map was used delineate functionally "eloquent" areas to avoid during surgery. During resection, the median nerve SEP was recorded from the strip electrode continuously. No significant change in the SEP was noted, and the patient awoke without any sensory deficits. Sensory mapping of the cortex is possible with a handheld monopolar electrode. This technique is easy to perform and can help reduce neurological morbidity. [ABSTRACT FROM AUTHOR]

Functional MRI is a well-established tool used for pre-surgical planning to help the neurosurgeon have a roadmap of critical functional areas that should be avoided, if possible, during surgery to minimize morbidity for patients with brain tumors (though this also has applications for surgical resection of epileptogenic tissue and vascular lesions). This article reviews the locations of secondary language centers within the brain along with imaging findings to help improve our confidence in our knowledge on language lateralization. Brief overviews of these language centers and their contributions to the language networks will be discussed. These language centers include primary language centers of “Broca’s Area” and “Wernicke’s Area”. However, there are multiple secondary language centers such as the dorsal lateral prefrontal cortex (DLPFC), frontal eye fields, pre- supplemental motor area (pre-SMA), Basal Temporal Language Area (BTLA), along with other areas of activation. Knowing these foci helps to increase self-assurance when discussing the nature of laterality with the neurosurgeon. By knowing secondary language centers for language lateralization, via fMRI, one can feel confident on providing neurosurgeon colleagues with appropriate information on the laterality of language in preparation for surgery.

Intraoperative functional mapping of tumor and peri-tumor tissue is a well-established technique for avoiding permanent neurologic deficits and maximizing extent of resection. Motor, language, and other cognitive domains may be assessed with intraoperative tasks. This article describes techniques used for motor and language mapping including awake mapping considerations in addition to less traditional intraoperative testing paradigms for cognition. It also discusses complications associated with mapping and insights into complication avoidance.

Functional MRI is a well-established tool used for pre-surgical planning to help the neurosurgeon have a roadmap of critical functional areas that should be avoided, if possible, during surgery to minimize morbidity for patients with brain tumors (though this also has applications for surgical resection of epileptogenic tissue and vascular lesions). This article reviews the locations of secondary language centers within the brain along with imaging findings to help improve our confidence in our knowledge on language lateralization. Brief overviews of these language centers and their contributions to the language networks will be discussed. These language centers include primary language centers of "Broca's Area" and "Wernicke's Area". However, there are multiple secondary language centers such as the dorsal lateral prefrontal cortex (DLPFC), frontal eye fields, pre- supplemental motor area (pre-SMA), Basal Temporal Language Area (BTLA), along with other areas of activation. Knowing these foci helps to increase self-assurance when discussing the nature of laterality with the neurosurgeon. By knowing secondary language centers for language lateralization, via fMRI, one can feel confident on providing neurosurgeon colleagues with appropriate information on the laterality of language in preparation for surgery. [ABSTRACT FROM AUTHOR]

Functional activation leads to an increase in local brain temperature via an increase in local perfusion. In the intraoperative setting, these cortical surface temperature fluctuations may be imaged using infrared thermography such that the activated brain areas are inferred. While it is known that temperature increases as a result of activation, a quantitative spatiotemporal description has yet to be achieved. A novel intraoperative infrared thermography device with data collection software was developed to isolate the thermal impulse response function. Device performance was validated using data from six patients undergoing awake craniotomy who participated in motor and sensory mapping tasks during infrared imaging following standard mapping with direct electrical stimulation. Shared spatiotemporal patterns of cortical temperature changes across patients were identified using group principal component analysis. Analysis of component time series revealed a thermal activation peak present across all patients with an onset delay of five seconds and a peak duration of ten seconds. Spatial loadings were converted to a functional map which showed strong correspondence to positive stimulation results for similar tasks. This component demonstrates the presence of a previously unknown impulse response function for functional mapping with infrared thermography. [ABSTRACT FROM AUTHOR]

Simple Summary: The increasing relevance given to sentinel lymph node assessment in veterinary medicine has led to the necessity of evaluating different mapping techniques and their combination. This study was performed in dogs with mast cell tumors after preoperative assessment identification of draining nodes using lymphoscintigraphy. The aim was to assess whether the addition of methylene blue dye to intraoperative detection of radioactivity in lymph nodes increased the surgical identification of such nodes. Dogs included totaled 103, for a total of 116 mast cell tumors and 196 biopsied lymph nodes. Adding the removal of blue-stained lymph nodes to radioactive positive nodes, the detection of metastatic lymph nodes increased from 90% to 95%. A low percentage of nodes detected in the single lymphocenter were both unstained and non-radioactive. Interestingly, all lymph nodes considered overtly metastatic at histopathology were radioactive. Only a few self-limiting side effects were recorded. The results of this study reported an advantage of the combination of intraoperative gamma probe and methylene blue for guiding the dissection of sentinel lymph nodes in dogs with mast cell tumors. Methylene Blue (MB) is combined with radiopharmaceutical for intraoperative sentinel lymph node (SLN) mapping, but its role during SLN extirpation has not been investigated yet in veterinary medicine. The aim of this study was to assess whether MB increased surgical detection of SLN beyond the use of intraoperative gamma-probe (IGP) alone in clinically node-negative dogs with mast cell tumors (MCTs) following the detection of sentinel lymphocentrums (SLCs) via preoperative planar lymphoscintigraphy. Dogs enrolled underwent MCT excision and SLC exploration guided by both MB and IGP. Data recorded for each SLN were staining (blue/non-blue), radioactivity (hot/non-hot), and histopathological status (HN0-1 vs. HN2-3). A total of 103 dogs bearing 80 cutaneous, 35 subcutaneous, and 1 mucocutaneous MCTs were included; 140 SLCs were explored, for a total of 196 SLNs removed. Associating MB with IGP raised the SLNs detection rate from 90% to 95%. A total of 44% of SLNs were metastatic: 86% were blue/hot, 7% were only blue, 5% were only hot, and 2% were non-blue/non-hot. All HN3 SLNs were hot. Combining MB with IGP can increase the rate of SLN detection in dogs with MCTs; nonetheless, all lymph nodes identified during dissection should be removed, as they might be unstained but metastatic. [ABSTRACT FROM AUTHOR]

Awake craniotomy (AC) is a critical neurosurgical technique for maximizing tumor resection in eloquent brain regions while preserving essential neurological functions like speech and motor control. Despite its widespread adoption, no prior bibliometric analysis has evaluated the most influential research in this field. This study analyzed the top 100 most-cited articles on AC to identify key trends, influential works, and authorship demographics. A systematic search of the Web of Science Core Collection on September 17, 2024, yielded 718 publications, with the top 100 ranked by citation count. Analysis revealed a surge in AC research after 2013, peaking in 2021, with the Journal of Neurosurgery contributing significantly (49 articles; 2,611 citations). Themes included functional mapping, anesthetic techniques, and patient outcomes, with technological advancements such as intraoperative MRI and virtual reality enhancing surgical precision. Authorship analysis highlighted a gender disparity, with male authors occupying 77% of first authorship and 88% of senior roles. These findings underscore AC's evolution, foundational studies, and ongoing advancements while emphasizing the need for greater diversity and inclusion in the field., Competing Interests: Conflicts of interest: In compliance with the ICMJE uniform disclosure form, all authors declare the following: Payment/services info: Zeiki Medical, Rio de Janeiro, Brazil, sponsored our work. Financial relationships: All authors have declared that they have no financial relationships at present or within the previous three years with any organizations that might have an interest in the submitted work. Other relationships: All authors have declared that there are no other relationships or activities that could appear to have influenced the submitted work., (Copyright © 2024, McBenedict et al.)

One of the major challenges during glioblastoma surgery is balancing between maximizing extent of resection and preventing neurological deficits. Several surgical techniques and adjuncts have been developed to help identify eloquent areas both preoperatively (fMRI, nTMS, MEG, DTI) and intraoperatively (imaging (ultrasound, iMRI), electrostimulation (mapping), cerebral perfusion measurements (fUS)), and visualization (5-ALA, fluoresceine)). In this review, we give an update of the state-of-the-art management of both primary and recurrent glioblastomas. We will review the latest surgical advances, challenges, and approaches that define the onco-neurosurgical practice in a contemporary setting and give an overview of the current prospective scientific efforts. [ABSTRACT FROM AUTHOR]

Objective: Surgical approach to low-grade glioma (LGG) involving the posterior insula is challenging, especially in the left hemisphere, with a high risk of sensorimotor, language, or visual deterioration. In this study, a case series of 5 right-handed patients harboring a left posterior insular LGG is reported, by detailing a transcorticosubcortical approach.Method: The five surgeries were achieved in awake patients using cortical and axonal electrostimulation mapping. The glioma was removed through the left rolandic and/or parietal opercula, with preservation of the subcortical connectivity.Results: The cortical mapping was positive in the five patients, enabling the selection of an optimal transcortical approach, via the anterolateral supramarginal gyrus in four patients and/or via the lateral retrocentral gyrus in three cases (plus through the left superior temporal gyrus in one case). Moreover, the white matter tracts were identified in all cases, i.e., the lateral part of the superior longitudinal fasciculus (five cases), the arcuate fasciculus (four cases), the thalamocortical somatosensory pathways (four cases), the motor pathway (one case), the semantic pathway (three cases), and the optic tract (one case). Complete resection of the LGG was achieved in two patients and near-total resection in three patients. There were no postoperative permanent sensorimotor, language, or visual deficits.Conclusion: A transcortical approach through the parietorolandic operculum in awake patients represents safe and effective access to the left posterior insular LGG. Detection and preservation of the functional connectivity using direct electrostimulation of the white matter bundles are needed in this cross-road brain region to prevent otherwise predictable postsurgical impairments.

Purpose: Resting‐state functional Magnetic Resonance Imaging (rs‐fMRI) is suggested to be a viable option for pre‐operative mapping for patients with brain tumours. However, it remains an open issue whether the tool is useful in the clinical setting compared to task‐based fMRI (T‐fMRI) and intraoperative mapping. Thus, a systematic review was conducted to investigate the usefulness of this technique. Methods: A systematic literature search of rs‐fMRI methods applied as a pre‐operative mapping tool was conducted using the PubMed/MEDLINE and Cochrane Library electronic databases following PRISMA guidelines. Results: Results demonstrated that 50% (six out of twelve) of the studies comparing rs‐fMRI and T‐fMRI showed good concordance for both language and sensorimotor networks. In comparison to intraoperative mapping, 86% (six out of seven) studies found a good agreement to rs‐fMRI. Finally, 87% (twenty out of twenty‐three) studies agreed that rs‐fMRI is a suitable and useful pre‐operative mapping tool. Conclusions: rs‐fMRI is a promising technique for pre‐operative mapping in assessing the functional brain areas. However, the agreement between rs‐fMRI with other techniques, including T‐fMRI and intraoperative maps, is not yet optimal. Studies to ascertain and improve the sophistication in pre‐processing of rs‐fMRI imaging data are needed. [ABSTRACT FROM AUTHOR]

The study of brain connectomics has led to a rapid evolution in the understanding of human brain function. Traditional localizationist theories are being replaced by more accurate network, or hodologic, approaches that model brain function as widespread processes dependent on cortical and subcortical structures, as well as the white matter tracts (WMTs) that link these areas. Recent surgical literature suggests that WMTs may be more critical to preserve than cortical structures because of the comparably lower capacity of recovery of the former when damaged. Given the relevance of eloquent WMTs to neurologic function and thus quality of life, neurosurgical interventions must be tailored to maximize their preservation. Direct electric stimulation remains a vital tool for identification and avoidance of these critical tracts. Neurosurgeons therefore require proper understanding of the anatomy and function of WMTs, as well as the reported contemporary tasks used during intraoperative stimulation. We review the relevant tracts involved in language, visuospatial, and motor networks and the updated direct electric stimulation–based mapping tasks that aid in their preservation. The dominant-hemisphere language WMTs have been mapped using picture naming, semantic association, word repetition, reading, and writing tasks. For monitoring of vision and spatial functions, the modified picture naming and line bisection tasks, as well as the recording of visual evoked potentials, have been used. Repetitive movements and monitoring of motor evoked potentials and involuntary movements have been applied for preservation of the motor networks. [ABSTRACT FROM AUTHOR]

Brain plasticity is an ongoing process of reorganization not only on the macroscopic level but also from underlying changes at the cellular and molecular levels of neurons. This evolution has not yet been fully understood. The objective of this paper is to review and understand neuroplasticity through the review of literature, imaging, and intraoperative evidence. [ABSTRACT FROM AUTHOR]

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Brain mapping with direct electric stimulation is considered the gold standard for maximum safe resection of tumors affecting eloquent regions. However, no consensus exists in selection and interpretation of intraoperative testing for language and other cognitive domains. Our aim was to capture and statistically analyze variability in practices in intraoperative language testing among neurosurgeons and neuropsychologists in the United States, Europe, and the rest of the world. An electronic questionnaire was developed by a multidisciplinary team at Queen Square, London, and distributed internationally through selected organized societies. The survey included 2 domains: terminology and common understanding of clinical deficits; and selection of intraoperative tests used per specific brain region. Participants were stratified by specialty, years of experience, and monthly caseload. Data were analyzed using Krippendorff α, Wilcoxon rank sum test, and Kruskal-Wallis analysis of variance. A total of 137 specialists participated. A low agreement was recorded for each of the 20 questions (Krippendorff α = −0.023 to 0.312). Further subgroup analysis revealed low interrater reliability independent of specialism (neurosurgeons, α = 0.013–0.318 compared with nonneurosurgeons, α = −0.021 to 0.398; P = 0.808) and years of experience (<1 years, α = −0.003 to 0.282; 2–5 years, α = 0.009–0.327; 6–10 years, α = 0.003–0.234; and >10 years, α = −0.003 to 0.372; P = 0.200). The current study documents high interrater variability, regardless of specialism and years of experience in the cohort of neurosurgeons and language specialists surveyed and may be applicable to a wider group of specialists, indicating the need to reduce interobserver, interinstitutional and interspecialty variability, reach consensus, and increase the validity, interpretation, and predictive power of intraoperative mapping. [ABSTRACT FROM AUTHOR]

Electrical stimulation mapping is a longstanding practice that aids in identification and delineation of eloquent cortex. Initially used to expand our understanding of the typical human cortex, it now plays a significant role in mapping cortical function in individuals with atypical structural and functional tissue organization undergoing epilepsy surgery. This review discusses the unique challenges that arise in the functional testing of the immature cortex of a child and the parameters of stimulation that optimize accurate results in conventional open implantation and in stereo-electroencephalography. The prerequisite baseline evaluation and preparation recommended to increase the yield from pediatric stimulation mapping sessions is described, as are ideal approaches to the mapping of the sensory, motor, language, and visual cortices. [ABSTRACT FROM AUTHOR]

Background: The ventricular tachycardia (VT) circuit is often assumed to be located in the endocardium or epicardium. The plateauing success rate of VT ablation warrants reevaluation of this mapping paradigm.Objective: The purpose of this study was to resolve the intramural components of VT circuits by mapping in human hearts.Methods: Panoramic simultaneous endocardial-epicardial mapping (SEEM) during intraoperative mapping (IOM) was performed in human subjects. In explanted hearts (EH), SEEM and intramural multielectrode plunge needle mapping (NM) of the left ventricle were performed. Overall, 37 VTs (26 ischemic cardiomyopathy [ICM], 11 nonischemic cardiomyopathy [NICM]) were studied in 32 patients. Intraoperative SEEM was performed in 16 patients (16 ICM). Additionally, 16 explanted myopathic human hearts (9 NICM, 7 ICM) were studied in a Langendorff setup. Predominant intramural location of the VT was imputed by the absence of significant endocardial-epicardial activation during IOM (using SEEM and no NM) or by the presence of intramural activation spanning the entire cycle length (including mid-diastole) in EH (SEEM and NM).Results: By IOM (SEEM), predominant endocardial activation (entire tachycardia cycle length including mid-diastolic activation) was present in 10 of 18 VTs (55%). In 8 of 18 VTs (44%), the VT circuit was presumed to be intramural due to incomplete diastolic activation in endocardium and epicardium. In EH (SEEM and NM), VT location was predominantly intramural, endocardial, and epicardial in 8 of 19 (42%), 5 of 19 (26%), and 1 of 19 VTs (5%), respectively.Conclusion: In a significant proportion of both ischemic and nonischemic ventricular tachycardias, the predominant activation was located in the intramural space. [ABSTRACT FROM AUTHOR]

Background: Complete tumor resection is a standard strategy in the surgical treatment of ventricular tachycardia (VT) associated with cardiac tumors. Recently, an intraoperative electroanatomic mapping system (CARTO) has enabled surgeons to target the localized arrhythmogenic substrate for partial resection and/or cryoablation in nonresectable cardiac tumors.Objective: The purpose of this study was to evaluate the surgical procedures and late outcomes of the treatment of VT associated with cardiac tumors.Methods: We examined six patients (age 1-65 years) who had undergone surgical treatment of VT associated with cardiac tumors between 2010 and 2016. The 4 pathologies of the cardiac tumors were lipoma 2, fibroma 2, hemangioma 1, and lymphoma 1. Intraoperative epicardial mapping using CARTO was performed in 5 patients(80%). Surgical procedures and long-term outcomes were evaluated.Results: Arrhythmogenic substrates with abnormal electrograms, such as fractionated or late potential, were identified locally or circumferentially beside the tumor in every patient. Complete tumor resection with cryoablation was performed in 3 patients. Two patients underwent partial tumor resection with cryoablation. Cryoablation without tumor resection was performed in 1 patient. No mortality and morbidity occurred. Additional catheter ablation was required in 2 patients to treat occurrence of nonclinical VT and induction of clinical VT during hospital stay. Mean follow-up time was 90 ± 52.5 months. There was no recurrence of clinical VT.Conclusion: The outcomes of surgical treatment of VT associated with cardiac tumors were excellent. Intraoperative CARTO mapping was beneficial to eliminate the VT substrates associated with nonresectable cardiac tumors. [ABSTRACT FROM AUTHOR]

We describe a 15-year-old girl who underwent intraoperative catheter ablation for the ventricular tachycardia associated with Ebstein's anomaly with functional pulmonary atresia and a small right ventricle (RV) after Fontan surgery. The computed tomography showed the dilated right atrium and RV due to the failure of RV plication. The activation mapping revealed that the ventricular tachycardia showed a focal pattern originating from the atrialized RV (aRV). With careful preparations, the procedure of catheter ablation combined with the adjustment of Starnes fenestration and plication of RV/atrialized RV was very effective for this patient. [ABSTRACT FROM AUTHOR]

The authors describe the awake surgical mapping of music skills for patients who require resection in brain areas that may support musical abilities. A 65-year-old man was diagnosed with an anterolateral right temporal nonenhancing lesion, likely a diffusely infiltrating glioma, after presenting with several episodes of altered taste and smell and one episode of loss of consciousness. The patient specializes in music and music technology and has composed scores for films. An awake surgery was planned in a semiseated position. Prerecorded melodies were designed preoperatively as a surrogate for a composition skill task. These consisted of 10- to 15-second musical clips played during bipolar electrical stimulation of the overlying cortex and were divided into three segments: listen, play, and accuracy check. During the "listen" phase, the patient listened to a musical prompt. During the "play" phase, he played a musical response on a keyboard. Stimulation at multiple temporal neocortical sites was negative for any alteration in task performance. The patient did well postoperatively with excellent clinical and radiographic results and returned to composing music without functional compromise. Musical composition tasks can be performed safely intraoperatively for patients with musical expertise. Whether stimulating more posterior nondominant temporal neocortex or other cortical or white matter locations can disrupt this task remains undetermined.

Highlights • This article reviews and forms recommendations for intraoperative SEPs. • It endorses SEP optimization to enhance surgical feedback speed and accuracy. • It supports an adaptive warning criterion to adjust for baseline drift and variability. Abstract Intraoperative somatosensory evoked potentials (SEPs) provide dorsal somatosensory system functional and localizing information, and complement motor evoked potentials. Correct application and interpretation require in-depth knowledge of relevant anatomy, electrophysiology, and techniques. It is advisable to facilitate cortical SEPs with total intravenous propofol–opioid or similarly favorable anesthesia. Moreover, SEP optimization is recommended to enhance surgical feedback speed and accuracy by maximizing signal-to-noise ratio (SNR); it consists of selecting highest-SNR peripheral and cortical derivations while omitting low-SNR channels. Confounding factors causing non-surgical SEP reduction should be excluded before issuing a warning. It is advisable to facilitate their identification with peripheral SEP controls and cortical SEP systemic controls whenever possible. Warning criteria should adjust for baseline drift and reproducibility. The recommended adaptive warning criterion is visually obvious amplitude reduction from recent pre-change values and clearly exceeding trial-to-trial variability, particularly when abrupt and focal. Acquisition and interpretation should be done by qualified technical and professional level personnel. Indications for SEP monitoring include intracranial, posterior fossa, and spinal neurosurgery, as well as orthopedic spine, cerebrovascular, and descending aortic surgery. Indications for SEP mapping include sensorimotor cortex and dorsal column midline identification. Future advances could modify current recommendations. [ABSTRACT FROM AUTHOR]

Background: Surgery on patients with lesions in the dominant hemisphere for language is best done with awake language mapping. Intraoperative MRI (iMRI) has also been proposed as an ideal method for tumor resection control in patients with primary brain tumors. Objectives: This study examines the feasibility of low-field iMRI during awake craniotomy and tumor resection. Methods: 36 patients underwent awake resection with a compact iMRI for guidance. Outcomes were grouped using an A–D classification. Outcome A was defined as gross total resection (GTR) without iMRI, B as GTR achieved secondary to iMRI findings, C as resection stopped due to mapping but prior to iMRI, and, finally, D as resection stopped after iMRI had showed residual tumor but subsequent mapping limited further resection. Results: Diagnoses included primary brain tumors in all but 2 patients: 1 had mesial temporal sclerosis and 1 cysticercosis. Overall, outcomes A and D were the most common with 12 patients each, outcome C was the least common occurring in only 3 patients, and outcome B occurred in 9 patients. Hence, in 12 patients, iMRI led to increased tumor resection while in another 12 brain mapping limited the extent of resection. Conclusions: Combined awake language and motor mapping and iMRI guidance is feasible for resection of brain lesions. A compact iMRI has unique advantages for this approach. [ABSTRACT FROM AUTHOR]

Background Hypoglossal nerve deficit is a possible complication caused by carotid endarterectomy (CEA). The accidental injury of the hypoglossal nerve during surgery is one of the major reasons for permanent hypoglossal nerve palsy. In this study, we investigated the usefulness of intraoperative mapping of the hypoglossal nerve to identify this nerve during CEA. Methods Five consecutive patients who underwent CEA for the treatment of symptomatic or asymptomatic carotid artery stenosis were studied. A hand-held probe was used to detect the hypoglossal nerve in the operative field, and the tongue motor evoked potentials (MEPs) were recorded. Results The tongue MEPs were obtained in all the patients. The invisible hypoglossal nerve was successfully identified without any difficulty when the internal carotid artery was exposed. Intraoperative mapping was particularly useful for identifying the hypoglossal nerve when the hypoglossal nerve passed beneath the posterior belly of the digastric muscle. In 1 of 2 cases, MEP was also elicited when the ansa cervicalis was stimulated, although the resulting amplitude was much smaller than that obtained by direct stimulation of the hypoglossal nerve. Postoperatively, none of the patients presented with hypoglossal nerve palsy. Conclusions Intraoperative hypoglossal nerve mapping enabled us to locate the invisible hypoglossal nerve during the exposure of the internal carotid artery accurately without retracting the posterior belly of the digastric muscle and other tissues in the vicinity of the internal carotid artery. [ABSTRACT FROM AUTHOR]

Background: Neurosurgeons use Ojemann cortical stimulators to map and localize cortical and subcortical regions of the brain to map functional areas intraoperatively to avoid resecting or damaging functional tissue. Here we describe a technique where, rather than using a separate retracting tool, a handheld Ojemann cortical stimulator was used to retract cerebral parenchyma while simultaneously stimulating descending white matter tracts to prevent accidental damage to white matter tracts involved with motor function. Case description: A 48-year-old patient developed intractable seizures and preoperative workup showed a left frontal brain mass close to her motor region. Subdural grid electrodes were implanted to localize the patient's ictal onset zone. The electrodes were then removed and the tumor was resected along with the ictal onset zone. During the resection, the neurosurgeon (S. Vadera) successfully utilized the Ojemann cortical stimulator to stimulate descending white matter tracts to prevent accidental injury to the patient and also retract cerebral parenchyma during resection. Four weeks post-operative, the patient had made a complete recovery and had no unforeseen deficits or weaknesses. Conclusion: Here we show that the Ojemann cortical stimulator can be used as an effective retraction tool as well as a cerebral parenchyma stimulator, effectively preventing accidental injury to functional tissue while concurrently giving the neurosurgeon a free hand to perform other tasks.

Brain metastases present a significant public health issue, affecting more than 100,000 patients per year in the U.S. and result in significant morbidity. Brain metastases can occur in a variety of clinical situations ranging from multiple brain metastases with uncontrolled systemic disease to a solitary metastasis in the setting of controlled systemic disease. Additionally, advances in genomics have broadened the opportunities for targeted treatment options and potentially more durable systemic responses. As such, the treatment of brain metastases is now more tailored and multimodal, involving systemic, radiation, and surgical therapies, often in combination. This review discusses the historical and current role of neurosurgical techniques in the treatment of brain metastases. [ABSTRACT FROM AUTHOR]

The authors report on an observational study designed to isolate the impact of navigated transcranial magnetic stimulation (nTMS) on surgical outcome in glioblastoma treatment. We undertook a controlled observational study to identify the additive impact of presurgical nTMS in patients scheduled for surgical treatment of glioblastoma in or near motor eloquent locations. The trial data is derived from a large university hospital with a differential availability of its nTMS mapping service at its two campuses, both equally served by a single neurosurgical department. When available, the nTMS cortical mapping data and nTMS-based fiber tractography are used for surgical planning and patient counseling as well as intraoperative identification of the primary motor cortex and guidance in subcortical motor mapping. The addition of preoperative nTMS mapping data to a clinical routine already incorporating preoperative fiber tractography and intraoperative neuronavigation and electrophysiology was shown to improve surgical outcomes by increasing the extent of resection, without compromising patient safety or long-term functional outcomes in comparison to the concurrent non-TMS control group. This study is the first to prove that the improved surgical outcomes observed in previous studies after the implementation of nTMS to presurgical work-up are not caused by any overall improvement in patient care or a paradigm shift toward more aggressive resection but by the additional functional data provided by nTMS. [ABSTRACT FROM AUTHOR]

Background: A crucial aspect of surgery on the supraclavicular region, lateral neck, and mid-cervical vertebral region is the identification and sparing of the phrenic nerve and cervical (C4) root that are responsible for diaphragmatic innervation. Therefore intraoperative mapping of these nerve structures can be useful for difficult cases. Electrical stimulation with simultaneous observation of the ventilator waveforms of the anesthesia machine provides an effective method for the precise intraoperative mapping of these structures. In the literature, there is only one publication reporting the use of one of the waveforms (capnography) for this purpose. Methods: Capnography and pressure-time waveforms, two mandatory curves in anesthesiological monitoring, were studied under electrical stimulation of the phrenic nerve (one patient) and the C4 root (eight patients). The aim was to detect changes that would verify diaphragmatic contraction. No modifications in anesthesia or surgery and no additional maneuvers were required. Results: In all patients, stimulation was followed by identifiable changes in the two waveforms, compatible with diaphragmatic contraction: acute reduction in amplitude on capnography and repetitive saw-like elevations on pressure-time curve. Frequency of patterns on pressure-time curve coincided with the frequency of stimulation; therefore the two recordings were complementary. Conclusions: This simple method proved effective in identifying the neural structures responsible for diaphragmatic function. We therefore suggest that it should be employed in the various types of surgery where these structures are at risk. [ABSTRACT FROM AUTHOR]

Glioblastomas (GBM), one of the most common tumors of the central nervous system, are associated with poor prognosis, even with all the scientific development of the last decades. Individual survival, however, is not homogenous among GBM patients, and multiple factors are related to their outcome, including age, biological characteristics of the tumor, and extent of treatment. Extent of resection (EOR) plays a major role as an independent modifiable factor associated with improved overall and progression-free survival. Achievement of maximal safe resection, removing as much as possible the tumor while preserving the neurological function, is the main goal of the current surgical treatment of GBM. To reach this objective, different technologies and surgical techniques have been introduced in neuro-oncology surgery, including functional neuronavigation systems, ultrasound surgery, intraoperative MRI scan, and intraoperative cortical and subcortical mapping techniques. In the current manuscript, we examine the impact of EOR on the prognosis of GBM patients and the benefits and limitations of modern adjuvant techniques used for resection of these lesions. [ABSTRACT FROM AUTHOR]

Introduction. For gliomas, the goal of surgery is maximal tumour removal with the preservation of neurological function. We evaluated the contribution of the combination of diffusion tensor imaging-based fibre tracking (DTI-FT) of the pyramidal tract (PT) integrated to the navigation and subcortical direct electrical stimulations (DESs) to surgical outcomes. Method. Ten patients underwent surgery for gliomas located in close relationship with the subcortical course of the PT. Preoperative DTI was performed with a three-Tesla magnetic resonance scanner applying an echo-planar sequence with 20 diffusion directions. DTI-FT data were systematically loaded into the navigation for intraoperative guidance. When the resection closely approached the PT as illustrated on navigation images, subcortical DESs were used to confirm the proximity of the PT by observing motor responses. The location of all subcortically stimulated points with positive motor response was correlated with the illustrated PT. Motor deficits were evaluated pre- and postoperatively, and compared with the extent of tumour removal. Results. DTI-FT of the PT was successfully performed in all patients. A total of fifteen positive subcortical DESs were obtained in 8 of 10 patients; in these cases, the mean distance from the stimulated point to the PT was 6.2 ± 3.6 mm. The mean tumoural volumetric resection was 90.8 ± 10.4%, with a gross total resection in four patients. At one month after surgery, only one patient had a slight impairment of motor function (decreased fine motor hand skills). Conclusions. DTI-FT is an accurate technique to map the PT in the vicinity of brain tumours. By combining anatomical (DTI-FT) and functional (subcortical DES) studies for intraoperative localization of the PT, the authors achieved a good volumetric resection of tumours located in eloquent motor areas, with low morbidity. Careful use of this protocol requires the knowledge of some pitfalls, mainly the occurrence of brain shift during removal of large tumours. [ABSTRACT FROM AUTHOR]

Highlights: [•] Direct electrical stimulation (DES) is an invaluable method for neuroscience. [•] Claims that DES is a poorly understood, potentially misleading method are unfounded. [•] DES has specific, causally interpretable effects at well-defined anatomical sites. [•] DES also reduces dramatically postoperative deficits in brain-damaged patients. [Copyright &y& Elsevier]

From its introduction in the early 1970s, intraoperative neurophysiological monitoring has evolved into an extremely useful and reliable adjunct for operating on the central and peripheral nervous system. This manuscript reviews the author’s experience with its evolution in his practice and how it impacts it today. [ABSTRACT FROM AUTHOR]

The use of intraoperative physiological monitoring has become increasingly common over the last decade and it is a useful tool to be employed for the resection of ependymomas of the central nervous system. This manuscript reviews the history of its development and its methodology with a particular emphasis on those aspects of particular importance during surgery on ependymomas. [ABSTRACT FROM AUTHOR]

Objective: To present a new technique to identify perineal and anal sphincter anatomy using an electrostimulator in order to facilitate anatomical repair.Methods: A neglected perineal tear was repaired using the technique described.Results: The patient's St Mark's incontinence score improved from 22 out of 24 to 6 out of 24.Conclusions: This technique may be practical and useful for intraoperative mapping of distorted perineal and anal anatomy to assist surgical repair. [ABSTRACT FROM AUTHOR]

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Background: Sudden cardiac death remains the leading cause of death, claiming more than 1000 lives per day in the United States alone. Noninvasive means to diagnose rhythm disorders of the heart have relied heavily on the 12-lead electrocardiogram and, to a lesser extent, on higher-resolution body-surface mapping. These lack sensitivity and specificity due to the smoothing effect of the torso volume conductor. In contrast, noninvasive electrocardiographic imaging (ECGI) reconstructs potentials, electrograms, and activation sequences directly on the heart surface from body-surface electrocardiograms and has been applied in animal as well as clinical studies. This presentation summarizes the application of ECGI for imaging epicardial arrhythmogenic substrates and associated properties, in particular, dispersion of myocardial repolarization, fractionated electrograms, and heterogeneous multipolar potential distributions.Methods: Electrocardiographic imaging was evaluated in a canine model of temperature-induced dispersion of myocardial repolarization through localized warming and cooling and in 3 patients with preserved left ventricular ejection fraction (>or=50%) undergoing open heart surgery. Noninvasively reconstructed epicardial potentials, electrograms (and derived measures), as well as activation sequences were compared with their measured counterparts.Results: Epicardial measures of dispersion of repolarization (activation recovery intervals [ARIs] and QRST integrals) accurately reflected the underlying repolarization properties: prolonged ARIs and increased QRST (warming), shortened ARIs and decreased QRST (cooling), and gradients of adjacent prolonged and shortened ARIs (increased and decreased QRST) during simultaneous warming and cooling. In open-heart surgery patients, ECGI reflected the underlying arrhythmogenic substrate by noninvasively reconstructing fractionated electrograms (cross-correlation with measured electrograms = 0.72 +/- 0.25), regions of heterogeneous multipolar potential distributions, and areas of slow conduction.Conclusion: These studies demonstrate that ECGI can capture and localize noninvasively important electrophysiologic properties of the heart. Its clinical significance lies in mapping arrhythmogenic substrates, evaluation and guidance of therapy, and risk stratification. [ABSTRACT FROM AUTHOR]

Cardiac Surgery for Arrhythmias. Cardiac arrhythmia surgery was initiated in 1968 with the first successful division of an accessory AV connection for the Wolff-Parkinson-White syndrome. Subsequent surgical procedures included the left atrial isolation procedure and right atrial isolation procedure for automatic atrial tachycardias, discrete cryosurgery of the AV node for AV nodal reentrant tachycardia, the atrial transection procedure, the corridor procedure, and the maze procedure for atrial fibrillation, the right ventricular disconnection procedure for arrhythmogenic right ventricular tachycardia, and the encircling endocardial ventriculotomy, subendocardial resection procedure, endocardial cryoablation, the Jatene procedure, and the Dor procedure for ischemic ventricular tachycardia. Because of monumental strides in the treatment of most refractory arrhythmias by endocardial catheter techniques during the past decade, the only remaining viable surgical procedures for cardiac arrhythmias are the maze procedure for atrial fibrillation and the Dor procedure for ischemic ventricular tachycardia. Nevertheless, the 25 to 30 years of intense activity in the field of cardiac arrhythmia surgery provided the essential foundation for the development of these catheter techniques and represent one of the most exciting and productive eras in the history of medicine. In one short professional career, we have witnessed the birth of arrhythmia surgery, its adolescence as an “esoteric” specialty, its prime as an enlightening yet exhausting period, and finally its waning years as a source of knowledge and wisdom upon which better methods of treatment have been founded. One could hardly ask for a more rewarding experience. (J Cardiovasc Electrophysiol, Vol. 15, pp. 250-262, February 2004) [ABSTRACT FROM AUTHOR]

COX, J.L., et al.: Cardiac Surgery for Arrhythmias. Cardiac arrhythmia surgery was initiated in 1968 with the first successful division of an accessory AV connection for the Wolff-Parkinson-White Syndrome. Subsequent surgical procedures included the left atrial isolation procedure and the right atrial isolation procedure for automatic atrial tachycardias, discrete cryosurgery of the AV node for AV nodal reentry tachycardia, the atrial transection procedure, corridor procedure and Maze procedure for atrial fibrillation, the right ventricular disconnection procedure for arrhythmogenic right ventricular tachycardia, the encircling endocardial ventriculotomy, subendocardial resection procedure, endocardial cryoablation, the Jatene procedure, and the Dor procedure for ischemic ventricular tachycardia. Because of monumental strides in the treatment of most refractory arrhythmias by endocardial catheter techniques during the past decade, the only remaining viable surgical procedures for cardiac arrhythmias are the Maze procedure for atrial fibrillation and the Dor procedure for ischemic ventricular tachycardia. Nevertheless, the 25–30 years of intense activity in the field of cardiac arrhythmia surgery provided the essential foundation for the development of these catheter techniques and represent one of the most exciting and productive eras in the history of medicine. In one short professional career, we have witnessed the birth of arrhythmia surgery, its adolescence as an “esoteric” specialty, its prime as an enlightening yet exhausting period, and finally its waning years as a source of knowledge and wisdom on which better methods of treatment have been founded. One could hardly ask for a more rewarding experience. (PACE 2004; 27:266–282) [ABSTRACT FROM AUTHOR]

Background: In patients with perieloquent tumors, neurosurgeons must use a variety of techniques to maximize survival while minimizing postoperative neurological morbidity. Recent publications have shown that conventional anatomical features may not always predict postoperative deficits. Additionally, scientific conceptualizations of complex brain function have shifted toward more dynamic, neuroplastic theories instead of traditional static, localizationist models. Functional imaging techniques have emerged as potential tools to incorporate these advances into modern neurosurgical care. In this case report, we describe our observations using preoperative transcranial magnetic stimulation data combined with tractography to guide a nontraditional surgical approach in a patient with a motor eloquent glioblastoma., Observations: The authors detail the use of preoperative functional and structural imaging to perform a gross total resection despite tumor infiltration of conventionally eloquent anatomical structures. The authors resected the precentral gyrus, specifically the paracentral lobule, localized using intraoperative mapping techniques. The patient demonstrated mild transient postoperative weakness and made a full neurological recovery by discharge 1 week later., Lessons: Preoperative functional and structural imaging has potential to not only optimize patient selection and surgical planning, but also facilitate important intraoperative decisions. Innovative preoperative imaging techniques should be optimized and used to identify safely resectable structures.

Designation of the time of local activation is fundamental to electrophysiological mapping. In normal myocardium, the minimum slope in extracellular monopolar (MP) electrograms has been linked through simultaneous intracellular and extracellular recordings to phase o of the action potential. However, no similar correlation has been demonstrated for a parameter from bipolar (BP) electrograms, now commonly used during electrophysiological studies and intraoperative mapping. The purpose of this work is to compare the activation time, determined according to several common algorithms applied to BP electrograms, with the time of the minimum slope in MP electrograms Simultaneous normal epicardial MP and BP electrograms were acquired from subjects undergoing surgery for Wolf-Parkinson-White Syndrome and from dogs. The activation time in BP electrograms was defined by four algorithms: (1) peak (P); (2) greatest absolute slope (S); (3) zero crossing of the segment containing the greatest slope (FZC); and (4) morphological (M). Each was compared to the time of the minimum slope in the simultaneously recorded MP response. The incidence of outliers was tabulated. The distribution o activation times computed using each BP algorithm was statistically different from the distribution of activation times derived from MP electrograms. M performed best (absolute difference: 2.6 ± 2.9 msec; cor coef: 0.9925 in man). The M, P, FZC, and S algorithms produced 3.2%. 3.5%, 4.7% and 4.7% outliers respectively. The overall performance of a morphologically based algorithm is superior to simplistic BP algorithms based only on slope or peak. [ABSTRACT FROM AUTHOR]

The purpose of this work is to determine the sensitivity of the estimated time of peaks and maximum slopes, commonly used in activation time computations, to the instant at which sampling is initiated. Based on complex and quickly changing waveforms, 471 monopolar (MP) and bipolar (BP) epicardial responses in man were selected. These were decimated from 10 kHz to simulate sampling at frequencies ranging from 200 Hz to 2,000 Hz. The peak and maximum absolute slope for BP and the minimum slope for MP were computed repeatedly starting at successive 100 µsec intervals extending throughout the sampling period and compared with these parameters computed from the waveform sampled at 10 kHz. Slopes were estimated using each of four different algorithms. The average greatest shift (AGS) due to variations in sampling onset ranged from 11.2 ± 3.5 (200 Hz) to 0.3 ± 0.2 msec (2,000 Hz). For bipolar algorithms, the peak performed better than the slope algorithms (AGS: 5.9 ± 3.3 to 0.3 ± 1.0 msec). For MP algorithms, 2 point linear, and 3 and 5 point Lagrange slope estimates performed similarly (AGS: 5.6 ± 3.3 to 0.3 ± 0.2 msec); a 5 point least square fit algorithm performed poorly. Sampling MP and BP electrograms below 500 and 400, respectively, often caused maximum shifts > 4 msec. Thus, the resolution of the peak and estimated slope is not limited to the sampling period, variations in initiation of sampling can cause significant outliers especially at low sampling rates, and MP electrograms should be sampled faster than BP electrograms for comparable accuracy. [ABSTRACT FROM AUTHOR]