Akiva Korn - Academia.edu (original) (raw)
Papers by Akiva Korn
The Journal of Pediatrics, Apr 1, 2014
Objective To determine the impact of fetal growth on postnatal amplitude-integrated electroenceph... more Objective To determine the impact of fetal growth on postnatal amplitude-integrated electroencephalography (aEEG) and power spectrum electroencephalography (EEG) data in preterm infants born with intrauterine growth restriction (IUGR). Study design We defined IUGR as birth weight <10th percentile, and control as birth weight appropriate for gestational age (GA). We performed single-channel (C3-C4) EEG during the first 48 hours of life and measured the upper and lower margins of the aEEG trace width. EEG readings were analyzed by spectral analysis, and the relative power of the frequency bands was calculated. The Lacey Assessment of the Preterm Infant was administered before discharge. Results We enrolled 14 infants with IUGR (mean GA, 34.3 AE 1.8 weeks; mean birth weight 1486 AE 304 g) and 16 appropriate for GA controls (mean GA, 33.7 AE 2 weeks; mean birth weight, 1978 AE 488 g). There were no significant between-group differences in perinatal complications. The mean aEEG trace width was 20.8 AE 1.4 mv in the infants with IUGR versus 17.3 AE 1.6 mv in controls (P < .001). The infants with IUGR also had significantly greater delta frequency activity and decreased theta, alpha, and beta frequency activities compared with controls. Delta frequency activity decreased with increasing GA
Journal of Clinical Neurophysiology, Jan 25, 2022
Purpose: To identify characteristics associated with higher incidence of intraoperative deteriora... more Purpose: To identify characteristics associated with higher incidence of intraoperative deterioration of neurophysiological potentials related to spinal tracts in cervical spine surgeries. Methods: Electrophysiological raw data and neurophysiological case reports of 1,611 patients from multiple medical centers, who underwent cervical spine surgery for decompression and/or fusion, were retrospectively reviewed. Patient-related and procedure-related variables were identified and analyzed for correlation with intraoperative neurophysiological event of the spinal tracts. The neurophysiological events were analyzed for identification of collective characteristics. Results: The study cohort presented consistent dominancy of male over female patients (67% vs. 33%). Intraoperative deterioration of spinal tract–derived potentials was noted in 10.5% of the total cases, which was not correlated with gender, age, or indication of the surgery. Higher incidence of neurophysiological events was noted in patients with impaired baseline of motor evoked potentials from the thenar muscle (P = 0.01) or somatosensory evoked potentials of the posterior tibial nerve (P = 0.0002). Procedures of circumferential approach or procedures that involved ≥3 spinal levels demonstrated higher incidence of neurophysiological events as well (P = 0.0003 and 0.001, respectively). Conclusions: Patients with deteriorated neurophysiological baseline and procedures of extensive intervention are at higher risk of intraoperative neurophysiological event in cervical spine surgery. Inclusion of intraoperative neurophysiological monitoring should be encouraged in complicated cases of cervical spine surgeries.
Journal of Neurosurgery, Feb 1, 2017
risk factors for shunt dependency after aneurysmal subarachnoid hemorrhage TO THE EDITOR: We read... more risk factors for shunt dependency after aneurysmal subarachnoid hemorrhage TO THE EDITOR: We read with great interest the article by Wilson et al. 21 (Wilson CD, Safavi-Abbasi S, Sun H, et al: Meta-analysis and systematic review of risk factors for shunt dependency after aneurysmal subarachnoid hemorrhage.
Operative Neurosurgery, Jul 25, 2020
BACKGROUND Percutaneous ablation of the cervical spinothalamic tract (STT) remains a therapeutic ... more BACKGROUND Percutaneous ablation of the cervical spinothalamic tract (STT) remains a therapeutic remedy for intractable cancer pain. However, it is accompanied by the risk of collateral damage to essential spinal cord circuitry, including the corticospinal tract (CST). Recent studies describe threshold-based mapping of the CST with the objective of motor bundle preservation during intramedullary spinal cord and supratentorial surgery. OBJECTIVE To assess the possibility that application of spinal cord mapping using intraoperative neuromonitoring in percutaneous cordotomy procedures may aid in minimizing iatrogenic motor tract injury. METHODS We retrospectively reviewed the files of 11 patients who underwent percutaneous cervical cordotomy for intractable oncological pain. We performed quantitative electromyogram (EMG) recordings to stimulation of the ablation needle prior to the STT-ablative stage. We compared evoked motor and sensory electrical thresholds, and the electrical span between them as a reliable method to confirm safe electrode location inside the STT. RESULTS Quantified EMG data were collected in 11 patients suffering from intractable cancer pain. The threshold range for evoking motor activity was 0.3 to 1.2 V. Stimulation artifacts were detected from trapezius muscles even at the lowest stimulation intensity, while thenar muscles were found to be maximally sensitive and specific. The minimal stimulation intensity difference between the motor and the sensory threshold, set as “Δ-threshold,” was 0.26 V, with no new motor deficit at 3 days or 1 month postoperatively. CONCLUSION Selective STT ablation is an effective procedure for treating intractable pain. It can be aided by quantitative evoked EMG recordings, with tailored parameters and thresholds.
Childs Nervous System, Aug 17, 2019
Purpose Utilization of intraoperative neurophysiology (ION) to map and assess various functions d... more Purpose Utilization of intraoperative neurophysiology (ION) to map and assess various functions during supratentorial brain tumor and epilepsy surgery is well documented and commonplace in the adult setting. The applicability has yet to be established in the pediatric age group. Methods All pediatric supratentorial surgery utilizing ION of the motor system, completed over a period of 10 years, was analyzed retrospectively for the following variables: preoperative and postoperative motor deficits, extent of resection, sensory-motor mappability and monitorability, location of lesion, patient age, and monitoring alarms. Intraoperative findings were correlated with antecedent symptomatology as well as short-and long-term postoperative clinical outcome. The monitoring impact on surgical course was evaluated on a per-case basis. Results Data were analyzed for 57 patients (ages 3-207 months (93 ± 58)). Deep lesions (in proximity to the pyramidal fibers) constituted 15.7% of the total group, superficial lesions 47.4%, lesions with both deep and superficial components 31.5%, and ventricular 5.2%. Mapping of the motor cortex was significantly more successful using the short-train technique than Penfield's technique (84% vs. 25% of trials, respectively), particularly in younger children. The youngest age at which motor mapping was successfully achieved was 3 vs. 93 months for each method, respectively. Preoperative motor strength was not associated with monitorability. Direct cortial motor evoked potential (dcMEP) was more sensitive than transcranial (tcMEP) in predicting postoperative motor decline. dcMEP decline was not associated with tumor grade or extent of resection (EOR); however, it was associated with lesion location and more prone to decline in deep locations. ION actively affected surgical decisions in several aspects, such as altering the corticectomy location and alarming due to a MEP decline. Conclusion ION is applicable in the pediatric population with certain limitations, depending mainly on age. When successful, ION has a positive impact on surgical decision-making, ultimately providing an added element of safety for these patients.
Acta neurochirurgica, Mar 8, 2014
Background Ependymomas are the most common glial neoplasms in the spinal cord. However, spinal co... more Background Ependymomas are the most common glial neoplasms in the spinal cord. However, spinal cord ependymomas presenting with regional dissemination along the neuroaxis are rare, with a yet undetermined standard of care. We retrospectively evaluated the management and outcomes of patients who were diagnosed with spinal ependymoma with regional metastases at presentation (SERMP). Methods Between 2002 and 2012, 16 patients with regionally metastatic spinal ependymomas were diagnosed and treated. The patients were retrospectively divided into two groups according to tumor grading and histological features. Nine patients were diagnosed with myxopapillary ependymomas (MPE), and seven patients were diagnosed with other lowgrade ependymomas. Results With a median follow-up of 46.4 months, 13 out of 16 patients had no postsurgical recurrence/progression of the disease. In three patients, the disease recurred/progressed, leading to death in one patient. There was no correlation between gross total removal (GTR) of the main tumor, or resection of the main lesion and the metastatic foci and increased progression free survival in patients of the MPE group. There was an advantage for patients diagnosed with other low-grade ependymomas. Adjuvant radiotherapy did not prove beneficial. Conclusions SERMP has a relatively benign course. Achieving GTR of both the main lesion and the metastases is preferable, but should not be achieved at any cost, especially in MPE interfering with the conus medullaris. The benefit of adjuvant radiotherapy remains unproven.
Acta neurochirurgica, Dec 15, 2015
Introduction Chiari malformation type I is defined as a descent of cerebellar tonsils below the l... more Introduction Chiari malformation type I is defined as a descent of cerebellar tonsils below the level of the foramen magnum. The traditional treatment for symptomatic patients is foramen magnum decompression (FMD) surgery. Intraoperative neurophysiological monitoring (INM) is an established surgical adjunct, which is proposed to reduce the potential risk of various surgical procedures. Though INM has been suggested as being helpful in patient positioning and in determining the optimal surgical extent of FMD (i.e., duroplasty, laminectomy, tonsillectomy), its shortcomings include prolongation of anesthesia and surgery as well as monetary costs. Multimodality INM including transcranial-electric motor evoked potential (TcMEP) is not routinely employed in most practices. This study evaluates efficacy of multimodality INM during FMD. Methods This work is a retrospective analysis of prospectively collected data. Twenty-two FMD surgeries in 21 pediatric patients (aged 1-18 years) were performed at our center utilizing multimodality INM. All patients presented Chiari malformation type I, 18 of which had presented with syringomyelia, underwent posterior fossa decompression (FMD + C1 laminectomy), accompanied in some with additional cervical laminectomies, duroplasty, and partial tonsillectomies. TcMEP and somatosensory evoked potentials (SSEP) were monitored throughout the procedure including before and after positioning. INM alarms were correlated with perioperative and long-term patient outcomes. Results INM data remained stable during 19 operations. Three cases displayed significant attenuation in the monitoring signals, all concomitant with patient positioning on the surgical table. One case showed attenuation in SSEP data only, which remained attenuated following repositioning. Another displayed altered TcMEP concomitant with positioning which partially stabilized following repositioning and resolved following bony decompression. The third case showed unilateral attenuation of both TcMEP and SSEP data, which did not rectify until closure. In each of these three cases, no new neurological deficits were observed post operatively. Conclusions Multimodality INM can be useful in FMD surgery, particularly during patient positioning. TcMEP attenuations may occur independent of SSEPs. The clinical implications of these monitoring alerts have yet to be defined. There is a need to establish an optimal, cost-effective monitoring protocol for FMD.
World Neurosurgery, May 1, 2017
Background Intraoperative electrophysiology is increasingly used for various lesion resections, b... more Background Intraoperative electrophysiology is increasingly used for various lesion resections, both in adult and pediatric brain surgery. Subcortical mapping is often used in adult surgery when lesions lie in proximity to the corticospinal tract (CST). We describe a novel technique of
Neurosurgical Review, Dec 15, 2018
The preferred treatment of patients with persistent, recurrent, or progressive syringomyelia afte... more The preferred treatment of patients with persistent, recurrent, or progressive syringomyelia after foramen magnum decompression (FMD) for Chiari I (CMI)-associated syringomyelia is controversial, and may include redo FMD, stabilization, or shunting procedures (such as syringopleural or syringo-subarachnoid shunts). We describe our experience in treating these patients and discuss the treatment modalities for these patients. We retrospectively collected data of CMI patients with persistent, recurrent, or progressive syringomyelia after FMD. In addition to baseline characteristics, surgical treatments and neurological and radiological outcomes were assessed. Further, we assessed through uni-and multivariate analyses possible technical, surgical, and radiological factors which might lead to failed FMD. Between 1998 and 2017, 48 consecutive patients (35 females (73%), average age 16.8 ± 11.5 years) underwent FMD for a syringomyelia-Chiari complex. Twenty-four patients (50%) underwent surgical treatment for a persistent (n = 10), progressive (n = 12), or recurrent (n = 2) syringomyelia 21.4 ± 27.9 months (median 14.6 months, range 12 days-134.9 months) after FMD. Of all analyzed factors, only extradural FMD was significantly associated with lower failure rates. Two patients (8%) underwent redo FMD, 18 (75%) underwent 19 syringo-subarachnoid-shunts, and 4 (17%) had 6 cranial CSF diversion procedures. The overall follow-up time was 40.1 ± 47.4 months (median 25 months, range 3-230 months). Based on our results, 50% of the patients undergoing FMD for syringomyelia-Chiari complex may require further surgical treatment due to persistent, progressive, or recurrent syringomyelia. Treatment should be tailored to the suspected underlying pathology. A subgroup of patients may be managed conservatively; however, these patients need close clinical and radiological follow-ups. The technical aspects of FMD in CMI-syrinx complex should be the focus of larger studies, as an effort to improve failure rates.
World Neurosurgery, Dec 1, 2017
Background Approximately 30% of patients treated by foramen magnum decompression (FMD) for Chiari... more Background Approximately 30% of patients treated by foramen magnum decompression (FMD) for Chiari I-associated-syringomyelia will show persistence, recurrence, or progression of the syrinx. Objective This study evaluates the clinical and radiological outcome of syringo-subarachnoid shunt (SSS) as the treatment for persistent syringomyelia after FMD. Methods Data was collected retrospectively. The primary outcome measurement was neurological function (assessed with the Modified Japanese Orthopedic Association (mJOA) scale). Secondary outcome measurements were surgical complications, re-operation rate, and syrinx status on magnetic resonance imaging (MRI). Results Twenty one patients (14 females (66.7%)) underwent SSS, either concurrent to the FMD, or at a later stage. Two minor surgical complications were seen, a wound dehiscence and postoperative kyphosis, both requiring revision surgery. No major complication or mortality occurred. The median change in the mJOA score was an improvement of 3 points out of the total of 17 points on the scale (mean follow up of 24.9 months). Expressed as a percentage, overall improvement was 11.8% (95% confidence interval 5.9-17.6; p<0.001). On postoperative MRI, shrinkage of the syrinx was seen in all patients but one, where the syrinx remained unchanged. Expressed as percentage, the improvement of the syrinx surface was 76.3% (95% confidence interval 65.0-87.7; p<0.001), while the improvement of syrinx span was 36.4% (95% confidence interval 21.8-50.9; p=0.05). Conclusion SSS for persistent, recurrent, or increasing syrinx following FMD for Chiari I malformation is a safe and effective surgical treatment when performed selectively by an experienced neurosurgeon.
Neurosurgery, Feb 20, 2019
BACKGROUND Surgical removal of intra-axial brain tumors aims at maximal tumor resection while pre... more BACKGROUND Surgical removal of intra-axial brain tumors aims at maximal tumor resection while preserving function. The potential benefit of awake craniotomy over craniotomy under general anesthesia (GA) for motor preservation is yet unknown. OBJECTIVE To compare the clinical outcomes of patients who underwent surgery for perirolandic tumors while either awake or under GA. METHODS Between 2004 and 2015, 1126 patients underwent surgical resection of newly diagnosed intra-axial tumors in a single institution. Data from 85 patients (44 awake, 41 GA) with full dataset who underwent resections for perirolandic tumors were retrospectively analyzed. RESULTS Identification of the motor cortex required significantly higher stimulation thresholds in anesthetized patients (9.1 ± 4 vs 6.2 ± 2.7 mA for awake patients, P = .0008). There was no group difference in the subcortical threshold for motor response used to assess the proximity of the lesion to the corticospinal (pyramidal) tract. High-grade gliomas were the most commonly treated pathology. The extent of resection and residual tumor volume were not different between groups. Postoperative motor deficits were more common in the anesthetized patients at 1 wk (P = .046), but no difference between the groups was detected at 3 mo. Patients in the GA group had a longer mean length of hospitalization (10.3 vs 6.7 d for the awake group, P = .003). CONCLUSION Awake craniotomy results in a better early postoperative motor outcome and shorter hospitalization compared with patients who underwent the same surgery under GA. The finding of higher cortical thresholds for the identification of the motor cortex in anesthetized patients may suggest an inhibitory effect of anesthetic agents on motor function.
Acta neurochirurgica, Mar 9, 2013
Avoiding iatrogenic neurological injury during spinal cord surgery is crucially important. Intrao... more Avoiding iatrogenic neurological injury during spinal cord surgery is crucially important. Intraoperative neurological monitoring (INM) has been widely used in a variety of spinal surgeries as a means of reducing the risk of intraoperative neurological insults. This study evaluates the benefits of INM specifically in spinal procedures for treatment of syringomyelia. Thirteen patients who underwent surgery for syrinx drainage with the assistance of INM were included in this study. In all patients both somatosensory-evoked potentials (SSEP) and motor-evoked potentials (MEP) were monitored. INM data and perioperative neurological evaluations were both recorded and analyzed. Eleven patients underwent syringo-subarachnoid shunt (SSAS) surgery. One patient underwent syrinx drainage and foramen magnum decompression (FMD). One patient underwent syringo-pleural shunt (SPA) surgery. Baseline MEP and SSEP were recordable at the beginning of surgery in 11 patients (&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;84 %). In the other two cases, baseline data from specific INM modalities were absent, correlating with the antecedent neurologic symptomotology. Two patients exhibited significant intraoperative changes in MEP data that influenced the course of surgery and prompted removal or re-insertion of the shunt. Mild and transient worsening of preoperative symptoms was reported in these instances. No new postoperative neurological deficits were reported in the other 11 patients in whom INM data were preserved throughout surgery. These data support routine use of INM in syringomyelia surgery. INM can alert the surgeon to potential intraoperative threats to the functional integrity of the spinal cord, providing a useful adjunct to spinal cord surgeries for the treatment of syringomyelia.
Journal of neurosurgery, Aug 1, 2017
I ntramedullary spinal cord tumors (IMSCTs) represent a rare entity in children and adults. 26,33... more I ntramedullary spinal cord tumors (IMSCTs) represent a rare entity in children and adults. 26,33 The most common intramedullary tumors can be classified as primary neoplasms or, less commonly, metastatic lesions. 19 Ependymomas are common in adults, while astrocytomas are far more common in children. 10 Most ependymomas have relatively demarcated borders, while astrocytomas are more infiltrative and need to be resected until a white matter "interphase" appears. 20 Microsurgical resection of IMSCTs is currently considered the primary treatment modality, while radiotherapy and/or chemotherapy are reserved for recurrent or malignant tumors. 3,9,41 The observation that the majority of IMSCTs are benign and consequently gross-total removal might result in long-term survival further supports the need for safe resection. 10 The extent of resection has been correlated with progression-free survival 4 and lower recurrence rates. 21 Advances in microsurgery have contributed to safer resection ability. However, despite all advances, surgery for IMSCTs is still very challenging and may carry significant morbidity. Proximity to crucial neural elements necessitates use of surgical adjuncts such as high-ABBREVIATIONS CMAP = compound motor action potential; CST = corticospinal tract; IMSCT = intramedullary spinal cord tumor; IONM = intraoperative neurophysiological monitoring; SSEP = somatosensory evoked potential; tcMEP = transcranial electric motor evoked potential.
PubMed, Apr 1, 2023
Multiple studies have demonstrated that the improved extent of resection for patients with glioma... more Multiple studies have demonstrated that the improved extent of resection for patients with glioma is associated with improved survival. The use of intraoperative electrophysiology cortical mapping to demonstrate function became a standard of care in modern neurosurgery and an indispensable tool to achieve the goal of maximal safe resection in tumor surgery. In this study, we review the brief history of intraoperative electrophysiology cortical mapping from the first cortical mapping study back in 1870 to the innovative tool of broad gamma cortical mapping used today.
Neuro-oncology, Nov 1, 2019
s vi180 NEURO-ONCOLOGY • NOVEMBER 2019 present an unusual case of a child with NB-associated OMS ... more s vi180 NEURO-ONCOLOGY • NOVEMBER 2019 present an unusual case of a child with NB-associated OMS whose OMS symptoms did not flare despite the use of immunotherapy to treat relapsed stage 4 disease. CONCLUSION: While immunosuppression is used to treat OMS and other paraneoplastic syndromes, the use of immunotherapy to treat the underlying malignancy may be tolerated. Further study is needed.
Journal of Neurosurgery, May 1, 2018
OBJECTIVE Resection of intraaxial tumors adjacent to the optic radiation (OR) may be associated w... more OBJECTIVE Resection of intraaxial tumors adjacent to the optic radiation (OR) may be associated with postoperative visual field (VF) deficits. Intraoperative navigation using MRI-based tractography and electrophysiological monitoring of the visual pathways may allow maximal resection while preserving visual function. In this study, the authors evaluated the value of visual pathway mapping in a series of patients undergoing awake craniotomy for tumor resection. METHODS A retrospective analysis of prospectively collected data was conducted in 18 patients who underwent an awake craniotomy for resection of intraaxial tumors involving or adjacent to the OR. Preoperative MRI-based tractography was used for intraoperative navigation, and intraoperative acquisition of 3D ultrasonography images was performed for real-time imaging and correction of brain shift. Goggles with light-emitting diodes were used as a standard visual stimulus. Direct cortical visual evoked potential (VEP) recording, subcortical recordings from the OR, and subcortical stimulation of the OR were used intraoperatively to assess visual function and proximity of the lesion to the OR. VFs were assessed pre-and postoperatively. RESULTS Baseline cortical VEP recordings were available for 14 patients (77.7%). No association was found between preoperative VF status and baseline presence of cortical VEPs (p = 0.27). Five of the 14 patients (35.7%) who underwent subcortical stimulation of the OR reported seeing phosphenes in the corresponding contralateral VF. There was a positive correlation (r = 0.899, p = 0.04) between the subcortical threshold stimulation intensity (3-11.5 mA) and the distance from the OR. Subcortical recordings from the OR demonstrated a typical VEP waveform in 10 of the 13 evaluated patients (76.9%). These waveforms were present only when recordings were obtained within 10 mm of the OR (p = 0.04). Seven patients (38.9%) had postoperative VF deterioration, and it was associated with a length of < 8 mm between the tumor and the OR (p = 0.05). CONCLUSIONS Intraoperative electrophysiological monitoring of the visual pathways is feasible but may be of limited value in preserving the functional integrity of the posterior visual pathways. Subcortical stimulation of the OR may identify the location of the OR when done in proximity to the pathways, but such proximity may be associated with increased risk of postoperative worsening of the VF deficit.
Journal of Neurosurgery, 2021
M axiMal resection of both high-and low-grade gliomas (LGGs) has been associated with better over... more M axiMal resection of both high-and low-grade gliomas (LGGs) has been associated with better overall survival. 8,23 However, acquired surgeryrelated neurological deficits can outweigh the benefit conferred by maximal resection and impair quality of life. Despite the aid of various intraoperative technologies, postoperative deficits are still a major concern, with a significant proportion of them resulting from ischemic complications. 15,22 Reported rates of surgery-related ischemic strokes range from 21% to 80%, and they were linked to new or worsened neurological deficits. 16,22 Moreover, surgically acquired neurological deficits were associated with impaired quality of life and even decreased survival. 19,31 The mixed populations with both high-and low-grade tumors in many studies have made it difficult to draw specific conclusions regarding strokes in LGG patients. Furthermore, most studies have not examined the long-term effects of these complications. 9,15,31 In this study we aimed to evaluate the incidence of ischemic events and their risk factors in patients undergoing surgery for LGG, as well as the short-and long-term clinical and functional implications. We also searched for ABBREVIATIONS DWI = diffusion-weighted imaging; EOR = extent of resection; IOM = intraoperative monitoring; KPS = Karnofsky Performance Status; LGG = low-grade glioma; MAP = mean arterial pressure; MEP = motor evoked potential; mRS = modified Rankin Scale; Tc-MEP = transcortical MEP.
PubMed, Apr 1, 2023
Introduction: The use of intraoperative electrical cortical stimulation (ECS) to map function is ... more Introduction: The use of intraoperative electrical cortical stimulation (ECS) to map function is the standard of care in modern neurosurgery. Recently, high gamma electrocorticography (hgECOG) mapping has had encouraging results. In this study we aim to compare hgECOG and fMRI with ECS for motor and language mapping. Methods: We retrospectively evaluated medical records of patients who underwent awake surgery for tumor resection between January 2018 and December 2021. The first 10 consecutive patients who underwent ECS and hgECOG for mapping of motor and language functions were defined as the study group. Pre- and intra-operative imaging and electrophysiology data were used for analysis. Results: ECS and hgECOG motor mapping demonstrated functional motor areas in 71.4% and 85.7% of patients, respectively. All motor areas identified with ECS were also demonstrated using hgECOG. In 2 patients, hgECOG-based mapping demonstrated motor areas not demonstrated with ECS but present in preoperative fMRI imaging. Of the 15 hgECOG tasks performed for language mapping, the findings of 6 (40%) were in accordance with the ECS mapping. Two (13.3%), showed language areas that were demonstrated using ECS and in addition, showed areas that were not. Four mappings (26.7%) showed language areas that were not demonstrated using ECS. In 3 mappings (20%), the functional areas identified by ECS were not demonstrated by hgECOG. Conclusions: Intraoperative hgECOG for mapping of motor and language functions provide a fast and reliable method without the risk of stimulation-induced seizures. Further studies are needed to assess functional outcome of patients undergoing hgECOG-guided tumor resection.
Blackwell Publishing Ltd eBooks, Feb 29, 2012
The Journal of Pediatrics, Apr 1, 2014
Objective To determine the impact of fetal growth on postnatal amplitude-integrated electroenceph... more Objective To determine the impact of fetal growth on postnatal amplitude-integrated electroencephalography (aEEG) and power spectrum electroencephalography (EEG) data in preterm infants born with intrauterine growth restriction (IUGR). Study design We defined IUGR as birth weight <10th percentile, and control as birth weight appropriate for gestational age (GA). We performed single-channel (C3-C4) EEG during the first 48 hours of life and measured the upper and lower margins of the aEEG trace width. EEG readings were analyzed by spectral analysis, and the relative power of the frequency bands was calculated. The Lacey Assessment of the Preterm Infant was administered before discharge. Results We enrolled 14 infants with IUGR (mean GA, 34.3 AE 1.8 weeks; mean birth weight 1486 AE 304 g) and 16 appropriate for GA controls (mean GA, 33.7 AE 2 weeks; mean birth weight, 1978 AE 488 g). There were no significant between-group differences in perinatal complications. The mean aEEG trace width was 20.8 AE 1.4 mv in the infants with IUGR versus 17.3 AE 1.6 mv in controls (P < .001). The infants with IUGR also had significantly greater delta frequency activity and decreased theta, alpha, and beta frequency activities compared with controls. Delta frequency activity decreased with increasing GA
Journal of Clinical Neurophysiology, Jan 25, 2022
Purpose: To identify characteristics associated with higher incidence of intraoperative deteriora... more Purpose: To identify characteristics associated with higher incidence of intraoperative deterioration of neurophysiological potentials related to spinal tracts in cervical spine surgeries. Methods: Electrophysiological raw data and neurophysiological case reports of 1,611 patients from multiple medical centers, who underwent cervical spine surgery for decompression and/or fusion, were retrospectively reviewed. Patient-related and procedure-related variables were identified and analyzed for correlation with intraoperative neurophysiological event of the spinal tracts. The neurophysiological events were analyzed for identification of collective characteristics. Results: The study cohort presented consistent dominancy of male over female patients (67% vs. 33%). Intraoperative deterioration of spinal tract–derived potentials was noted in 10.5% of the total cases, which was not correlated with gender, age, or indication of the surgery. Higher incidence of neurophysiological events was noted in patients with impaired baseline of motor evoked potentials from the thenar muscle (P = 0.01) or somatosensory evoked potentials of the posterior tibial nerve (P = 0.0002). Procedures of circumferential approach or procedures that involved ≥3 spinal levels demonstrated higher incidence of neurophysiological events as well (P = 0.0003 and 0.001, respectively). Conclusions: Patients with deteriorated neurophysiological baseline and procedures of extensive intervention are at higher risk of intraoperative neurophysiological event in cervical spine surgery. Inclusion of intraoperative neurophysiological monitoring should be encouraged in complicated cases of cervical spine surgeries.
Journal of Neurosurgery, Feb 1, 2017
risk factors for shunt dependency after aneurysmal subarachnoid hemorrhage TO THE EDITOR: We read... more risk factors for shunt dependency after aneurysmal subarachnoid hemorrhage TO THE EDITOR: We read with great interest the article by Wilson et al. 21 (Wilson CD, Safavi-Abbasi S, Sun H, et al: Meta-analysis and systematic review of risk factors for shunt dependency after aneurysmal subarachnoid hemorrhage.
Operative Neurosurgery, Jul 25, 2020
BACKGROUND Percutaneous ablation of the cervical spinothalamic tract (STT) remains a therapeutic ... more BACKGROUND Percutaneous ablation of the cervical spinothalamic tract (STT) remains a therapeutic remedy for intractable cancer pain. However, it is accompanied by the risk of collateral damage to essential spinal cord circuitry, including the corticospinal tract (CST). Recent studies describe threshold-based mapping of the CST with the objective of motor bundle preservation during intramedullary spinal cord and supratentorial surgery. OBJECTIVE To assess the possibility that application of spinal cord mapping using intraoperative neuromonitoring in percutaneous cordotomy procedures may aid in minimizing iatrogenic motor tract injury. METHODS We retrospectively reviewed the files of 11 patients who underwent percutaneous cervical cordotomy for intractable oncological pain. We performed quantitative electromyogram (EMG) recordings to stimulation of the ablation needle prior to the STT-ablative stage. We compared evoked motor and sensory electrical thresholds, and the electrical span between them as a reliable method to confirm safe electrode location inside the STT. RESULTS Quantified EMG data were collected in 11 patients suffering from intractable cancer pain. The threshold range for evoking motor activity was 0.3 to 1.2 V. Stimulation artifacts were detected from trapezius muscles even at the lowest stimulation intensity, while thenar muscles were found to be maximally sensitive and specific. The minimal stimulation intensity difference between the motor and the sensory threshold, set as “Δ-threshold,” was 0.26 V, with no new motor deficit at 3 days or 1 month postoperatively. CONCLUSION Selective STT ablation is an effective procedure for treating intractable pain. It can be aided by quantitative evoked EMG recordings, with tailored parameters and thresholds.
Childs Nervous System, Aug 17, 2019
Purpose Utilization of intraoperative neurophysiology (ION) to map and assess various functions d... more Purpose Utilization of intraoperative neurophysiology (ION) to map and assess various functions during supratentorial brain tumor and epilepsy surgery is well documented and commonplace in the adult setting. The applicability has yet to be established in the pediatric age group. Methods All pediatric supratentorial surgery utilizing ION of the motor system, completed over a period of 10 years, was analyzed retrospectively for the following variables: preoperative and postoperative motor deficits, extent of resection, sensory-motor mappability and monitorability, location of lesion, patient age, and monitoring alarms. Intraoperative findings were correlated with antecedent symptomatology as well as short-and long-term postoperative clinical outcome. The monitoring impact on surgical course was evaluated on a per-case basis. Results Data were analyzed for 57 patients (ages 3-207 months (93 ± 58)). Deep lesions (in proximity to the pyramidal fibers) constituted 15.7% of the total group, superficial lesions 47.4%, lesions with both deep and superficial components 31.5%, and ventricular 5.2%. Mapping of the motor cortex was significantly more successful using the short-train technique than Penfield's technique (84% vs. 25% of trials, respectively), particularly in younger children. The youngest age at which motor mapping was successfully achieved was 3 vs. 93 months for each method, respectively. Preoperative motor strength was not associated with monitorability. Direct cortial motor evoked potential (dcMEP) was more sensitive than transcranial (tcMEP) in predicting postoperative motor decline. dcMEP decline was not associated with tumor grade or extent of resection (EOR); however, it was associated with lesion location and more prone to decline in deep locations. ION actively affected surgical decisions in several aspects, such as altering the corticectomy location and alarming due to a MEP decline. Conclusion ION is applicable in the pediatric population with certain limitations, depending mainly on age. When successful, ION has a positive impact on surgical decision-making, ultimately providing an added element of safety for these patients.
Acta neurochirurgica, Mar 8, 2014
Background Ependymomas are the most common glial neoplasms in the spinal cord. However, spinal co... more Background Ependymomas are the most common glial neoplasms in the spinal cord. However, spinal cord ependymomas presenting with regional dissemination along the neuroaxis are rare, with a yet undetermined standard of care. We retrospectively evaluated the management and outcomes of patients who were diagnosed with spinal ependymoma with regional metastases at presentation (SERMP). Methods Between 2002 and 2012, 16 patients with regionally metastatic spinal ependymomas were diagnosed and treated. The patients were retrospectively divided into two groups according to tumor grading and histological features. Nine patients were diagnosed with myxopapillary ependymomas (MPE), and seven patients were diagnosed with other lowgrade ependymomas. Results With a median follow-up of 46.4 months, 13 out of 16 patients had no postsurgical recurrence/progression of the disease. In three patients, the disease recurred/progressed, leading to death in one patient. There was no correlation between gross total removal (GTR) of the main tumor, or resection of the main lesion and the metastatic foci and increased progression free survival in patients of the MPE group. There was an advantage for patients diagnosed with other low-grade ependymomas. Adjuvant radiotherapy did not prove beneficial. Conclusions SERMP has a relatively benign course. Achieving GTR of both the main lesion and the metastases is preferable, but should not be achieved at any cost, especially in MPE interfering with the conus medullaris. The benefit of adjuvant radiotherapy remains unproven.
Acta neurochirurgica, Dec 15, 2015
Introduction Chiari malformation type I is defined as a descent of cerebellar tonsils below the l... more Introduction Chiari malformation type I is defined as a descent of cerebellar tonsils below the level of the foramen magnum. The traditional treatment for symptomatic patients is foramen magnum decompression (FMD) surgery. Intraoperative neurophysiological monitoring (INM) is an established surgical adjunct, which is proposed to reduce the potential risk of various surgical procedures. Though INM has been suggested as being helpful in patient positioning and in determining the optimal surgical extent of FMD (i.e., duroplasty, laminectomy, tonsillectomy), its shortcomings include prolongation of anesthesia and surgery as well as monetary costs. Multimodality INM including transcranial-electric motor evoked potential (TcMEP) is not routinely employed in most practices. This study evaluates efficacy of multimodality INM during FMD. Methods This work is a retrospective analysis of prospectively collected data. Twenty-two FMD surgeries in 21 pediatric patients (aged 1-18 years) were performed at our center utilizing multimodality INM. All patients presented Chiari malformation type I, 18 of which had presented with syringomyelia, underwent posterior fossa decompression (FMD + C1 laminectomy), accompanied in some with additional cervical laminectomies, duroplasty, and partial tonsillectomies. TcMEP and somatosensory evoked potentials (SSEP) were monitored throughout the procedure including before and after positioning. INM alarms were correlated with perioperative and long-term patient outcomes. Results INM data remained stable during 19 operations. Three cases displayed significant attenuation in the monitoring signals, all concomitant with patient positioning on the surgical table. One case showed attenuation in SSEP data only, which remained attenuated following repositioning. Another displayed altered TcMEP concomitant with positioning which partially stabilized following repositioning and resolved following bony decompression. The third case showed unilateral attenuation of both TcMEP and SSEP data, which did not rectify until closure. In each of these three cases, no new neurological deficits were observed post operatively. Conclusions Multimodality INM can be useful in FMD surgery, particularly during patient positioning. TcMEP attenuations may occur independent of SSEPs. The clinical implications of these monitoring alerts have yet to be defined. There is a need to establish an optimal, cost-effective monitoring protocol for FMD.
World Neurosurgery, May 1, 2017
Background Intraoperative electrophysiology is increasingly used for various lesion resections, b... more Background Intraoperative electrophysiology is increasingly used for various lesion resections, both in adult and pediatric brain surgery. Subcortical mapping is often used in adult surgery when lesions lie in proximity to the corticospinal tract (CST). We describe a novel technique of
Neurosurgical Review, Dec 15, 2018
The preferred treatment of patients with persistent, recurrent, or progressive syringomyelia afte... more The preferred treatment of patients with persistent, recurrent, or progressive syringomyelia after foramen magnum decompression (FMD) for Chiari I (CMI)-associated syringomyelia is controversial, and may include redo FMD, stabilization, or shunting procedures (such as syringopleural or syringo-subarachnoid shunts). We describe our experience in treating these patients and discuss the treatment modalities for these patients. We retrospectively collected data of CMI patients with persistent, recurrent, or progressive syringomyelia after FMD. In addition to baseline characteristics, surgical treatments and neurological and radiological outcomes were assessed. Further, we assessed through uni-and multivariate analyses possible technical, surgical, and radiological factors which might lead to failed FMD. Between 1998 and 2017, 48 consecutive patients (35 females (73%), average age 16.8 ± 11.5 years) underwent FMD for a syringomyelia-Chiari complex. Twenty-four patients (50%) underwent surgical treatment for a persistent (n = 10), progressive (n = 12), or recurrent (n = 2) syringomyelia 21.4 ± 27.9 months (median 14.6 months, range 12 days-134.9 months) after FMD. Of all analyzed factors, only extradural FMD was significantly associated with lower failure rates. Two patients (8%) underwent redo FMD, 18 (75%) underwent 19 syringo-subarachnoid-shunts, and 4 (17%) had 6 cranial CSF diversion procedures. The overall follow-up time was 40.1 ± 47.4 months (median 25 months, range 3-230 months). Based on our results, 50% of the patients undergoing FMD for syringomyelia-Chiari complex may require further surgical treatment due to persistent, progressive, or recurrent syringomyelia. Treatment should be tailored to the suspected underlying pathology. A subgroup of patients may be managed conservatively; however, these patients need close clinical and radiological follow-ups. The technical aspects of FMD in CMI-syrinx complex should be the focus of larger studies, as an effort to improve failure rates.
World Neurosurgery, Dec 1, 2017
Background Approximately 30% of patients treated by foramen magnum decompression (FMD) for Chiari... more Background Approximately 30% of patients treated by foramen magnum decompression (FMD) for Chiari I-associated-syringomyelia will show persistence, recurrence, or progression of the syrinx. Objective This study evaluates the clinical and radiological outcome of syringo-subarachnoid shunt (SSS) as the treatment for persistent syringomyelia after FMD. Methods Data was collected retrospectively. The primary outcome measurement was neurological function (assessed with the Modified Japanese Orthopedic Association (mJOA) scale). Secondary outcome measurements were surgical complications, re-operation rate, and syrinx status on magnetic resonance imaging (MRI). Results Twenty one patients (14 females (66.7%)) underwent SSS, either concurrent to the FMD, or at a later stage. Two minor surgical complications were seen, a wound dehiscence and postoperative kyphosis, both requiring revision surgery. No major complication or mortality occurred. The median change in the mJOA score was an improvement of 3 points out of the total of 17 points on the scale (mean follow up of 24.9 months). Expressed as a percentage, overall improvement was 11.8% (95% confidence interval 5.9-17.6; p<0.001). On postoperative MRI, shrinkage of the syrinx was seen in all patients but one, where the syrinx remained unchanged. Expressed as percentage, the improvement of the syrinx surface was 76.3% (95% confidence interval 65.0-87.7; p<0.001), while the improvement of syrinx span was 36.4% (95% confidence interval 21.8-50.9; p=0.05). Conclusion SSS for persistent, recurrent, or increasing syrinx following FMD for Chiari I malformation is a safe and effective surgical treatment when performed selectively by an experienced neurosurgeon.
Neurosurgery, Feb 20, 2019
BACKGROUND Surgical removal of intra-axial brain tumors aims at maximal tumor resection while pre... more BACKGROUND Surgical removal of intra-axial brain tumors aims at maximal tumor resection while preserving function. The potential benefit of awake craniotomy over craniotomy under general anesthesia (GA) for motor preservation is yet unknown. OBJECTIVE To compare the clinical outcomes of patients who underwent surgery for perirolandic tumors while either awake or under GA. METHODS Between 2004 and 2015, 1126 patients underwent surgical resection of newly diagnosed intra-axial tumors in a single institution. Data from 85 patients (44 awake, 41 GA) with full dataset who underwent resections for perirolandic tumors were retrospectively analyzed. RESULTS Identification of the motor cortex required significantly higher stimulation thresholds in anesthetized patients (9.1 ± 4 vs 6.2 ± 2.7 mA for awake patients, P = .0008). There was no group difference in the subcortical threshold for motor response used to assess the proximity of the lesion to the corticospinal (pyramidal) tract. High-grade gliomas were the most commonly treated pathology. The extent of resection and residual tumor volume were not different between groups. Postoperative motor deficits were more common in the anesthetized patients at 1 wk (P = .046), but no difference between the groups was detected at 3 mo. Patients in the GA group had a longer mean length of hospitalization (10.3 vs 6.7 d for the awake group, P = .003). CONCLUSION Awake craniotomy results in a better early postoperative motor outcome and shorter hospitalization compared with patients who underwent the same surgery under GA. The finding of higher cortical thresholds for the identification of the motor cortex in anesthetized patients may suggest an inhibitory effect of anesthetic agents on motor function.
Acta neurochirurgica, Mar 9, 2013
Avoiding iatrogenic neurological injury during spinal cord surgery is crucially important. Intrao... more Avoiding iatrogenic neurological injury during spinal cord surgery is crucially important. Intraoperative neurological monitoring (INM) has been widely used in a variety of spinal surgeries as a means of reducing the risk of intraoperative neurological insults. This study evaluates the benefits of INM specifically in spinal procedures for treatment of syringomyelia. Thirteen patients who underwent surgery for syrinx drainage with the assistance of INM were included in this study. In all patients both somatosensory-evoked potentials (SSEP) and motor-evoked potentials (MEP) were monitored. INM data and perioperative neurological evaluations were both recorded and analyzed. Eleven patients underwent syringo-subarachnoid shunt (SSAS) surgery. One patient underwent syrinx drainage and foramen magnum decompression (FMD). One patient underwent syringo-pleural shunt (SPA) surgery. Baseline MEP and SSEP were recordable at the beginning of surgery in 11 patients (&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;84 %). In the other two cases, baseline data from specific INM modalities were absent, correlating with the antecedent neurologic symptomotology. Two patients exhibited significant intraoperative changes in MEP data that influenced the course of surgery and prompted removal or re-insertion of the shunt. Mild and transient worsening of preoperative symptoms was reported in these instances. No new postoperative neurological deficits were reported in the other 11 patients in whom INM data were preserved throughout surgery. These data support routine use of INM in syringomyelia surgery. INM can alert the surgeon to potential intraoperative threats to the functional integrity of the spinal cord, providing a useful adjunct to spinal cord surgeries for the treatment of syringomyelia.
Journal of neurosurgery, Aug 1, 2017
I ntramedullary spinal cord tumors (IMSCTs) represent a rare entity in children and adults. 26,33... more I ntramedullary spinal cord tumors (IMSCTs) represent a rare entity in children and adults. 26,33 The most common intramedullary tumors can be classified as primary neoplasms or, less commonly, metastatic lesions. 19 Ependymomas are common in adults, while astrocytomas are far more common in children. 10 Most ependymomas have relatively demarcated borders, while astrocytomas are more infiltrative and need to be resected until a white matter "interphase" appears. 20 Microsurgical resection of IMSCTs is currently considered the primary treatment modality, while radiotherapy and/or chemotherapy are reserved for recurrent or malignant tumors. 3,9,41 The observation that the majority of IMSCTs are benign and consequently gross-total removal might result in long-term survival further supports the need for safe resection. 10 The extent of resection has been correlated with progression-free survival 4 and lower recurrence rates. 21 Advances in microsurgery have contributed to safer resection ability. However, despite all advances, surgery for IMSCTs is still very challenging and may carry significant morbidity. Proximity to crucial neural elements necessitates use of surgical adjuncts such as high-ABBREVIATIONS CMAP = compound motor action potential; CST = corticospinal tract; IMSCT = intramedullary spinal cord tumor; IONM = intraoperative neurophysiological monitoring; SSEP = somatosensory evoked potential; tcMEP = transcranial electric motor evoked potential.
PubMed, Apr 1, 2023
Multiple studies have demonstrated that the improved extent of resection for patients with glioma... more Multiple studies have demonstrated that the improved extent of resection for patients with glioma is associated with improved survival. The use of intraoperative electrophysiology cortical mapping to demonstrate function became a standard of care in modern neurosurgery and an indispensable tool to achieve the goal of maximal safe resection in tumor surgery. In this study, we review the brief history of intraoperative electrophysiology cortical mapping from the first cortical mapping study back in 1870 to the innovative tool of broad gamma cortical mapping used today.
Neuro-oncology, Nov 1, 2019
s vi180 NEURO-ONCOLOGY • NOVEMBER 2019 present an unusual case of a child with NB-associated OMS ... more s vi180 NEURO-ONCOLOGY • NOVEMBER 2019 present an unusual case of a child with NB-associated OMS whose OMS symptoms did not flare despite the use of immunotherapy to treat relapsed stage 4 disease. CONCLUSION: While immunosuppression is used to treat OMS and other paraneoplastic syndromes, the use of immunotherapy to treat the underlying malignancy may be tolerated. Further study is needed.
Journal of Neurosurgery, May 1, 2018
OBJECTIVE Resection of intraaxial tumors adjacent to the optic radiation (OR) may be associated w... more OBJECTIVE Resection of intraaxial tumors adjacent to the optic radiation (OR) may be associated with postoperative visual field (VF) deficits. Intraoperative navigation using MRI-based tractography and electrophysiological monitoring of the visual pathways may allow maximal resection while preserving visual function. In this study, the authors evaluated the value of visual pathway mapping in a series of patients undergoing awake craniotomy for tumor resection. METHODS A retrospective analysis of prospectively collected data was conducted in 18 patients who underwent an awake craniotomy for resection of intraaxial tumors involving or adjacent to the OR. Preoperative MRI-based tractography was used for intraoperative navigation, and intraoperative acquisition of 3D ultrasonography images was performed for real-time imaging and correction of brain shift. Goggles with light-emitting diodes were used as a standard visual stimulus. Direct cortical visual evoked potential (VEP) recording, subcortical recordings from the OR, and subcortical stimulation of the OR were used intraoperatively to assess visual function and proximity of the lesion to the OR. VFs were assessed pre-and postoperatively. RESULTS Baseline cortical VEP recordings were available for 14 patients (77.7%). No association was found between preoperative VF status and baseline presence of cortical VEPs (p = 0.27). Five of the 14 patients (35.7%) who underwent subcortical stimulation of the OR reported seeing phosphenes in the corresponding contralateral VF. There was a positive correlation (r = 0.899, p = 0.04) between the subcortical threshold stimulation intensity (3-11.5 mA) and the distance from the OR. Subcortical recordings from the OR demonstrated a typical VEP waveform in 10 of the 13 evaluated patients (76.9%). These waveforms were present only when recordings were obtained within 10 mm of the OR (p = 0.04). Seven patients (38.9%) had postoperative VF deterioration, and it was associated with a length of < 8 mm between the tumor and the OR (p = 0.05). CONCLUSIONS Intraoperative electrophysiological monitoring of the visual pathways is feasible but may be of limited value in preserving the functional integrity of the posterior visual pathways. Subcortical stimulation of the OR may identify the location of the OR when done in proximity to the pathways, but such proximity may be associated with increased risk of postoperative worsening of the VF deficit.
Journal of Neurosurgery, 2021
M axiMal resection of both high-and low-grade gliomas (LGGs) has been associated with better over... more M axiMal resection of both high-and low-grade gliomas (LGGs) has been associated with better overall survival. 8,23 However, acquired surgeryrelated neurological deficits can outweigh the benefit conferred by maximal resection and impair quality of life. Despite the aid of various intraoperative technologies, postoperative deficits are still a major concern, with a significant proportion of them resulting from ischemic complications. 15,22 Reported rates of surgery-related ischemic strokes range from 21% to 80%, and they were linked to new or worsened neurological deficits. 16,22 Moreover, surgically acquired neurological deficits were associated with impaired quality of life and even decreased survival. 19,31 The mixed populations with both high-and low-grade tumors in many studies have made it difficult to draw specific conclusions regarding strokes in LGG patients. Furthermore, most studies have not examined the long-term effects of these complications. 9,15,31 In this study we aimed to evaluate the incidence of ischemic events and their risk factors in patients undergoing surgery for LGG, as well as the short-and long-term clinical and functional implications. We also searched for ABBREVIATIONS DWI = diffusion-weighted imaging; EOR = extent of resection; IOM = intraoperative monitoring; KPS = Karnofsky Performance Status; LGG = low-grade glioma; MAP = mean arterial pressure; MEP = motor evoked potential; mRS = modified Rankin Scale; Tc-MEP = transcortical MEP.
PubMed, Apr 1, 2023
Introduction: The use of intraoperative electrical cortical stimulation (ECS) to map function is ... more Introduction: The use of intraoperative electrical cortical stimulation (ECS) to map function is the standard of care in modern neurosurgery. Recently, high gamma electrocorticography (hgECOG) mapping has had encouraging results. In this study we aim to compare hgECOG and fMRI with ECS for motor and language mapping. Methods: We retrospectively evaluated medical records of patients who underwent awake surgery for tumor resection between January 2018 and December 2021. The first 10 consecutive patients who underwent ECS and hgECOG for mapping of motor and language functions were defined as the study group. Pre- and intra-operative imaging and electrophysiology data were used for analysis. Results: ECS and hgECOG motor mapping demonstrated functional motor areas in 71.4% and 85.7% of patients, respectively. All motor areas identified with ECS were also demonstrated using hgECOG. In 2 patients, hgECOG-based mapping demonstrated motor areas not demonstrated with ECS but present in preoperative fMRI imaging. Of the 15 hgECOG tasks performed for language mapping, the findings of 6 (40%) were in accordance with the ECS mapping. Two (13.3%), showed language areas that were demonstrated using ECS and in addition, showed areas that were not. Four mappings (26.7%) showed language areas that were not demonstrated using ECS. In 3 mappings (20%), the functional areas identified by ECS were not demonstrated by hgECOG. Conclusions: Intraoperative hgECOG for mapping of motor and language functions provide a fast and reliable method without the risk of stimulation-induced seizures. Further studies are needed to assess functional outcome of patients undergoing hgECOG-guided tumor resection.
Blackwell Publishing Ltd eBooks, Feb 29, 2012