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To identify characteristics associated with higher incidence of intraoperative deterioration of neurophysiological potentials related to spinal tracts in cervical spine surgeries.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.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).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.

Background Ventral thoracic meningiomas may pose a technical challenge owing to a limited surgical corridor and the presence of long-standing ventral cord compression. Unopposed dorsal spinal cord migration may occur following a laminectomy resulting in immediate neurologic injury. We discuss the possible mechanism underlying such a phenomenon, suggesting alternative approach to prevent neurologic injury. Methods Two patients operated on for ventral thoracic meningioma and sustained neurologic compromise were retrospectively evaluated. Image editing software was used for 3D modeling to simulate the possible underlying mechanism of injury. Cases where ventral thoracic meningiomas were approached via unilateral hemilaminectomy, performed in 2020, were retrospectively analyzed and compared with the laminectomy approach cohort. Results Two patients sustained postoperative neurologic function decline following resection of ventral thoracic meningioma via the laminectomy approach. Both exhibited permanent abolishment of transcranial motor evoked potentials (MEPs) following laminectomy. Based on the extrapolated 3D models for these two cases, dorsal cord migration was postulated as the cause for the acute neurologic compromise. Conclusion Laminectomy for resection of thoracic ventral meningioma may lead in some cases to dorsal cord migration resulting in grave neurologic deterioration. Unilateral approach to these tumors restricts the dorsal migration and may mitigate neurologic outcomes.

Filum terminale lipomas (FTL) represent a sub-type of spinal lipomas, where there is fatty infiltration of the filum. It becomes a surgical entity when it manifests as clinical or radiological tethered cord syndrome. Intraoperative neuromonitoring (IONM) has been suggested as a valuable tool in children for tethered cord surgeries. FTL is distinct and cannot be compared with complex tethered cord syndrome (TCS). Untethering an FTL is a relatively straightforward microsurgical exercise, usually based on anatomical findings. Neurological morbidity in FTL untethering is extremely low. The necessity of IONM in FTL has not been evaluated. The objective of this study was to identify the role of IONM in untethering an FTL Available electronic data and case files were interrogated to identify children (0–18 years) who underwent an untethering of FTL between 2008 and 2019. We had a shift in our policy and tried to use IONM as often as possible in all tethered cord surgery from 2014. All children were categorised under ‘IONM implemented’ or ‘no IONM’ group. Outcomes analysed were as follows: (1) Clinical status on short-term and long-term follow-up, (2) alteration of surgical course by IONM and (3) complications specifically associated with IONM Among 80 children included in this study, IONM was implemented in 37 children and 43 children underwent untethering without IONM. 32.5% of children were ‘syndromic’. Seventy-five percent of children were under age 3 years during surgery. Both groups (No IONM vs. IONM implemented) were well matched in most variables. Majority of ‘no IONM’ surgeries were performed prior to 2014. There was no neurological morbidity in the entire cohort. Mean duration of follow-up was 49.10 (± 33.67) months. Short-term and long-term clinical status remained stable in both cohorts. In 16 children, the filum was stimulated. Based on our protocol, majority had a negative response. One child showed a positive response, contradicted by thorough microscopic inspection. Despite a positive response, the filum was untethered. IONM was not associated with any complication in this study. FTL untethering is an inherently low-risk microsurgery in experienced hands with rarely reported neurological morbidity. IONM may not be required for all FTL and may be used more judiciously.

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.

Creative thinking represents a major evolutionary mechanism that greatly contributed to the rapid advancement of the human species. The ability to produce novel and useful ideas, or original thinking, is thought to correlate well with unexpected, synchronous activation of several large-scale, dispersed cortical networks, such as the default network (DN). Despite a vast amount of correlative evidence, a causal link between default network and creativity has yet to be demonstrated. Surgeries for resection of brain tumors that lie in proximity to speech related areas are performed while the patient is awake to map the exposed cortical surface for language functions. Such operations provide a unique opportunity to explore human behavior while disrupting a focal cortical area via focal electrical stimulation. We used a novel paradigm of individualized direct cortical stimulation to examine the association between creative thinking and the DN. Preoperative resting-state fMRI was used to map the DN in individual patients. A cortical area identified as a DN node (study) or outside the DN (controls) was stimulated while the participants performed an alternate-uses-task (AUT). This task measures divergent thinking through the number and originality of different uses provided for an everyday object. Baseline AUT performance in the operating room was positively correlated with DN integrity. Direct cortical stimulation at the DN node resulted in decreased ability to produce alternate uses, but not in the originality of uses produced. Stimulation in areas that when used as network seed regions produced a network similar to the canonical DN was associated with reduction of creative fluency. Stimulation of areas that did not produce a default-like network (controls) did not alter creative thinking. This is the first study to causally link the DN and creative thinking.

OBJECTIVE The use of intraoperative neuromonitoring (IONM) has become an imperative adjunct to the resection of intramedullary spinal cord tumors (IMSCTs). While the diagnostic utility of IONM during the immediate postoperative period has been previously studied, its long-term diagnostic accuracy has seldom been thoroughly assessed. The aim of this study was to evaluate long-term variations in the diagnostic accuracy of transcranial motor evoked potentials (tcMEPs), somatosensory evoked potentials (SSEPs), and D-wave recordings during IMSCT excision. METHODS The authors performed a retrospective evaluation of imaging studies, patient charts, operative reports, and IONM recordings of patients who were operated on for gross-total or subtotal resection of IMSCTs at a single institution between 2012 and 2018. Variations in the specificity, sensitivity, positive predictive value (PPV), and negative predictive value (NPV) for postoperative functional outcome (McCormick Scale) were analyzed at postoperative day 1 (POD1), 6 weeks postoperatively (PO-6 weeks), and at the latest follow-up. RESULTS Overall, 28 patients were included. The mean length of follow-up was 19 ± 23.4 months. Persistent motor attenuations occurred in 71.4% of the cohort. MEP was the most sensitive modality (78.6%, 87.5%, and 85.7% sensitivity at POD1, PO-6 weeks, and last follow-up, respectively). The specificity of the D-wave was the most consistent over time (100%, 83.35%, and 90% specificity at the aforementioned time points). The PPV of motor recordings decreased over time (58% vs 33% and 100% vs 0 for tcMEP and D-wave at POD1 and last follow-up, respectively), while their NPV consistently increased (67% vs 89% and 70% vs 100% for tcMEP and D-wave at POD1 and last follow-up, respectively). CONCLUSIONS The diagnostic accuracy of IONM in the resection of IMSCTs varies during the postoperative period. The decrease in the PPV of motor recordings over time suggests that this method is more predictive of short-term rather than long-term neurological deficits. The increasing NPV of motor recordings indicates a higher diagnostic accuracy in the identification of patients who preserve neurological function, albeit with an increased proportion of false-negative alarms for the immediate postoperative period. These variations should be considered in the surgical decision-making process when weighing the risk of resection-associated neurological injury against the implications of incomplete tumor resection.

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. 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. 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. 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.

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.

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 continuous subcortical mapping using an electrified Cavitron UltraSonic Aspirator (CUSA) in children with supratentorial lesions.We evaluated the method of subcortical mapping using a CUSA as a stimulation probe. Included in this study were children (18 years of age) with supratentorial lesions in proximity to the CST in which the CUSA stimulator was applied. Data were collected retrospectively.Eleven children were included. Lesions were located in the thalamus (3), basal-ganglia (2), lateral ventricle (1), and convexity (5). Lesions included low-grade gliomas (6), arteriovenous malformation (1), cavernoma (1), cortical dysplasia (1), ependymoma grade II (1), and high-grade glioma (1). Seven patients had positive mapping responses to CUSA-based stimulation at various stimulation intensities. These responses led to a more limited resection in 5 cases. There were no complications related to the mapping technique.Continuous CUSA-based subcortical stimulation is a feasible mapping technique for assessing proximity to the CST during resection of supratentorial lesions in children. Future studies should be performed to better correlate the current threshold for eliciting a motor response with the distance from the CST, as well as the effect of age on this technique.

Highlights • Lower extremity (LE) muscles demonstrate intraoperative excitability differences. • Abductor hallucis is a suitable LE muscle for monitoring the corticospinal tract (CST). • CST monitoring with two LE muscles includes advantages but also practical limitations., Objective This study examines and compares excitability characteristics of tibialis anterior (TA) and abductor hallucis (AH) transcranial motor evoked potentials (tcMEP) during anterior cervical decompression and fusion (ACDF) surgery. Methods Electrophysiological and clinical data of 89 patients who underwent ACDF procedure were retrospectively reviewed. TcMEP data of TA and AH muscles from 178 limbs were analyzed for availability, robustness and stability during the procedure. Results TA tcMEP was available at 83% whereas AH tcMEP was available at 99% of the monitored lower limbs at preposition baseline. Availability of both TA and AH tcMEP was demonstrated in 147/178 limbs. The baseline amplitude of AH tcMEP was significantly greater than that of TA tcMEP recorded from the same limb (744.6 ± 54.0 and 326.9 ± 33.3 µV, respectively). Simultaneous deterioration of TA and AH tcMEP data was demonstrated in 10/147 limbs. Deterioration of either TA or AH tcMEP data accompanied by unchanged tcMEP data from the other lower limb muscle was noted in 32/147 compared to 1/147 limbs, respectively. The deteriorated TA and AH tcMEP data returned to baseline before closing at incidence of 17% compared to 46%, respectively. No new lower extremity (LE) neurological deficit was presented postoperatively in any patient. Conclusions AH tcMEP is a more reliable candidate than TA tcMEP for intraoperative LE monitoring in ACDF procedure. Significance The excitability differentials in LE tcMEP in ACDF is a variable that need to be considered while interpreting intraoperative neurophysiological data.

BACKGROUND Postoperative neurological deficits may outweigh the benefit conferred by maximal resection of gliomas. We evaluated the incidence of ischemic events in patients undergoing surgery for low-grade gliomas (LGG) and the long-term neurological and cognitive sequelae. METHODS Between 2013–2017, 168 patients underwent surgical resection or biopsy for LGG at our center. A full dataset, including pre- and postoperative magnetic resonance imaging (MRI) and long-term clinical evaluation findings, was available for 82 patients (study group). Ischemic complications, overall and progression-free survival, and functional and neurocognitive outcomes were evaluated. RESULTS The immediate postoperative MRI revealed an acute ischemic stroke adjacent to the tumor resection cavity in 19 patients (23%), 13 of whom developed new neurological deficits due to the ischemic event. Infarcts were more common in patients with recurrent tumors, especially those involving the Sylvian fissure (p< 0.05). Surgery for insular gliomas had the strongest association with postoperative infarcts. Survival of patients w/wo a postoperative infarct was the same. The median Karnofsky-Performance Status was lower for the infarct group vs. the non-infarct group at 3 months post-surgery (p=0.016), with a gradual significant improvement for the former over one year (p=0.04). Immediately after surgery, 27% of the patients without infarcts and 58% of those with infarcts experienced a new motor deficit (p=0.037), decreasing to 16% (p=0.028) and 37% (p=0.001), respectively, at one year. Neurocognitive analysis findings before and 3 months after surgery were unchanged, but patients with an infarct had a significant decrease in naming (p=0.04). Confusion during awake craniotomy was a strong predictor of an ischemic stroke. CONCLUSIONS Intraoperative strokes are more prevalent among patients who undergo recurrent surgeries, especially in the insula. Although they do not affect survival, these strokes negatively impact the patients’ activity and performance status, especially during the first 3 postoperative months, with gradual functional improvement over one year.

OBJECTIVEIschemic complications are a common cause of neurological deficits following low-grade glioma (LGG) surgeries. In this study, the authors evaluated the incidence, risk factors, and long-term implications of intraoperative ischemic events.METHODSThe authors retrospectively evaluated patients who had undergone resection of an LGG between 2013 and 2017. Analysis included pre- and postoperative demographic, clinical, radiological, and anesthetic data, as well as intraoperative neurophysiology data, overall survival, and functional and neurocognitive outcomes.RESULTSAmong the 82 patients included in the study, postoperative diffusion-weighted imaging showed evidence of acute ischemic strokes in 19 patients (23%), 13 of whom (68%) developed new neurological deficits. Infarcts were more common in recurrent and insular surgeries (p < 0.05). Survival was similar between the patients with and without infarcts. Immediately after surgery, 27% of the patients without infarcts and 58% of those with infarcts experienced motor deficits (p = 0.024), decreasing to 16% (p = 0.082) and 37% (p = 0.024), respectively, at 1 year. Neurocognitive functions before and 3 months after surgery were generally stable for the two groups, with the exception of a decline in verbal rhyming ability among patients with infarcts. Confusion during awake craniotomy was a strong predictor of the occurrence of an ischemic stroke. Mean arterial pressure at the beginning of surgery was significantly lower in the infarct group.CONCLUSIONSRecurrent surgeries and insular tumor locations are risk factors for intraoperative strokes. Although they do not affect survival, these strokes negatively affect patient activity and performance status, mainly during the first 3 postoperative months, with gradual functional improvement over 1 year. Several intraoperative parameters may suggest the impending development of an infarct.

Background “Kissing” neurofibromas (KNs) are a unique group of spinal tumors found in neurofibromatosis type 1 (NF1) patients. These are bilateral neurofibromas that approximate each other at the same level, with significant impingement compression of the cord or thecal sac. The best management options and surgical strategies for NF1 patients with KN have not been standardized. Methods We conducted a retrospective study evaluating adult NF1 patients with KN. All patients are followed routinely at the Gilbert Israeli NF Center. Patients' files were reviewed for natural history, imaging features, surgical technique, and surgical outcome. Results Twelve patients with at least 1 pair of KN were identified (6 females). Median age at spinal presentation was 24 (range 17–48). KNSs were located at the cervical (n = 8) and lumbar (n = 8) region, with no thoracic involvement. Seven of the 12 patients were operated; all underwent surgery due to cervical compression with progressive myelopathy. Four patients remained asymptomatic during the follow-up period. Three patients underwent multiple operations. Operative outcome was favorable in 71% of patients, with marked overall motor improvement or stabilization of neurologic deterioration. Two patients who entered surgery with a low functional reserve deteriorated after surgery. Conclusions In our series, KN caused progressive cord compression in 7 of the 8 patients with cervical tumors. No intervention was needed for lumbar tumors. Cervical tumors should be followed closely, with a low threshold for intervention. NF1 patients harboring KN should be followed both clinically and radiologically for life.

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.

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. 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. 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. 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.

Introduction: Intraoperative cardiovascular complications were previously demonstrated in relation to high sympathetic nervous system outflow or stimulation of the vagal nerve nucleus during theneurosurgical procedures on brain tumors. Main Symptoms and Important Clinical Findings: We are presenting clinical case of 13-year-old girl who suffered from midbrain glioma and developed life threatening cardiovascular events during neurosurgical procedure after surgicel hemostatic agent application. Therapeutic Interventions and Outcomes: Cardiovascular stability has been restored after immediate removal of surgicel from the operating field. We believe that it might be related to direct application of the surgicel hemostatic agent.

OBJECTIVEResection 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.METHODSA 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.RESULTSBaseline 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).CONCLUSIONSIntraoperative 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.

Intramedullary spinal cord tumors (IMSCTs) represent a rare entity, accounting for 4%–10% of all central nervous system tumors. Microsurgical resection of IMSCTs is currently considered the primary treatment modality. Intraoperative neurophysiological monitoring (IONM) has been shown to aid in maximizing tumor resection and minimizing neurological morbidity, consequently improving patient outcome. The gold standard for IONM to date is multimodality monitoring, consisting of both somatosensory evoked potentials, as well as muscle-based transcranial electric motor evoked potentials (tcMEPs). Monitoring of tcMEPs is optimal when combining transcranial electrically stimulated muscle tcMEPs with D-wave monitoring. Despite continuous monitoring of these modalities, when classic monitoring techniques are used, there can be an inherent delay in time between actual structural or vascular-based injury to the corticospinal tracts (CSTs) and its revelation. Often, tcMEP stimulation is precluded by the surgeon’s preference that the patient not twitch, especially at the most crucial times during resection. In addition, D-wave monitoring may require a few seconds of averaging until updating, and can be somewhat indiscriminate to laterality. Therefore, a method that will provide immediate information regarding the vulnerability of the CSTs is still needed.The authors performed a retrospective series review of resection of IMSCTs using the tip of an ultrasonic aspirator for continuous proximity mapping of the motor fibers within the spinal cord, along with classic muscle-based tcMEP and D-wave monitoring.The authors present their preliminary experience with 6 patients who underwent resection of an IMSCT using the tip of an ultrasonic aspirator for continuous proximity mapping of the motor fibers within the spinal cord, together with classic muscle-based tcMEP and D-wave monitoring. This fusion of technologies can potentially assist in optimizing resection while preserving neurological function in these challenging surgeries.

Direct cortical stimulation (DCS) is considered the gold-standard for functional cortical mapping during awake surgery for brain tumor resection. DCS is performed by stimulating one local cortical area at a time. We present a feasibility study using an intra-operative technique aimed at improving our ability to map brain functions which rely on activity in distributed cortical regions. Following standard DCS, Multi-Site Stimulation (MSS) was performed in 15 patients by applying simultaneous cortical stimulations at multiple locations. Language functioning was chosen as a case-cognitive domain due to its relatively well-known cortical organization. MSS, performed at sites that did not produce disruption when applied in a single stimulation point, revealed additional language dysfunction in 73% of the patients. Functional regions identified by this technique were presumed to be significant to language circuitry and were spared during surgery. No new neurological deficits were observed in any of the patients following surgery. Though the neuro-electrical effects of MSS need further investigation, this feasibility study may provide a first step towards sophistication of intra-operative cortical mapping.

Approximately 30% of patients treated with foramen magnum decompression (FMD) for Chiari I-associated syringomyelia will show persistence, recurrence, or progression of the syrinx.This study evaluates the clinical and radiologic outcomes of syringo-subarachnoid shunt (SSS) as the treatment for persistent syringomyelia after FMD.Data were collected retrospectively. The primary outcome measurement was neurologic function (assessed with the Modified Japanese Orthopedic Association [mJOA] scale). Secondary outcome measurements were surgical complications, reoperation rate, and syrinx status on magnetic resonance imaging (MRI).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 out of a possible 17 points on the scale (mean follow-up, 24.9 months). Expressed as a percentage, overall improvement was 11.8% (95% confidence interval [CI], 5.9-17.6; P0.001). On postoperative MRI, shrinkage of the syrinx was seen in all but 1 patient in whom the syrinx remained unchanged. Expressed as percentage, the improvement of the syrinx surface was 76.3% (95% CI, 65.0-87.7; P0.001), and the improvement of syrinx span was 36.4% (95% CI, 21.8-50.9; P = 0.05).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.

Object Intraoperative seizures during awake craniotomy may interfere with patients' ability to cooperate throughout the procedure, and it may affect their outcome. The authors have assessed the occurrence of intraoperative seizures during awake craniotomy in regard to tumor location and the isocitrate dehydrogenase 1 (IDH1) status of the tumor. Methods Data were collected in 137 consecutive patients who underwent awake craniotomy for removal of a brain tumor. The authors performed a retrospective analysis of the incidence of seizures based on the tumor location and its IDH1 mutation status, and then compared the groups for clinical variables and surgical outcome parameters. Results Tumor location was strongly associated with the occurrence of intraoperative seizures. Eleven patients (73%) with tumor located in the supplementary motor area (SMA) experienced intraoperative seizures, compared with 17 (13.9%) with tumors in the other three non-SMA brain regions (p < 0.0001). Interestingly, there was no significant association between history of seizures and tumor location (p = 0.44). Most of the patients (63.6%) with tumor in the SMA region harbored an IDH1 mutation compared with those who had tumors in non-SMA regions. Thirty-one of 52 patients (60%) with a preoperative history of seizures had an IDH1 mutation (p = 0.02), and 15 of 22 patients (68.2%) who experienced intraoperative seizures had an IDH1 mutation (p = 0.03). In a multivariate analysis, tumor location was found as a significant predictor of intraoperative seizures (p = 0.002), and a trend toward IDH1 mutation as such a predictor was found as well (p = 0.06). Intraoperative seizures were not associated with worse outcome. Conclusions Patients with tumors located in the SMA are more prone to develop intraoperative seizures during awake craniotomy compared with patients who have a tumor in non-SMA frontal areas and other brain regions. The IDH1 mutation was more common in SMA region tumors compared with other brain regions, and may be an additional risk factor for the occurrence of intraoperative seizures.

Object Awake craniotomy for removal of intraaxial tumors within or adjacent to eloquent brain regions is a well-established procedure. However, awake craniotomy failures have not been well characterized. In the present study, the authors aimed to analyze and assess the incidence and causes for failed awake craniotomy. Methods The database of awake craniotomies performed at Tel Aviv Medical Center between 2003 and 2010 was reviewed. Awake craniotomy was considered a failure if conversion to general anesthesia was required, or if adequate mapping or monitoring could not have been achieved. Results Of 488 patients undergoing awake craniotomy, 424 were identified as having complete medical, operative, and anesthesiology records. The awake craniotomies performed in 27 (6.4%) of these 424 patients were considered failures. The main causes of failure were lack of intraoperative communication with the patient (n = 18 [4.2%]) and/or intraoperative seizures (n = 9 [2.1%]). Preoperative mixed dysphasia (p < 0.001) and treatment with phenytoin (p = 0.0019) were related to failure due to lack of communication. History of seizures (p = 0.03) and treatment with multiple antiepileptic drugs (p = 0.0012) were found to be related to failure due to intraoperative seizures. Compared with the successful awake craniotomy group, a significantly lower rate of gross-total resection was achieved (83% vs 54%, p = 0.008), there was a higher incidence of short-term speech deterioration postoperatively (6.1% vs 23.5%, p = 0.0017) as well as at 3 months postoperatively (2.3% vs 15.4%, p = 0.0002), and the hospitalization period was longer (4.9 ± 6.2 days vs 8.0 ± 10.1 days, p < 0.001). Significantly more major complications occurred in the failure group (4 [14.8%] of 27) than in the successful group (16 [4%] of 397) (p = 0.037). Conclusions Failures of awake craniotomy were associated with a lower incidence of gross-total resection and increased postoperative morbidity. The majority of awake craniotomy failures were preventable by adequate patient selection and avoiding side effects of drugs administered during surgery.

To evaluate the frequency of loss of neurophysiological potentials during head positioning, the usefulness of head repositioning to restore the potentials, and the effect on neurological outcome.We retrospectively reviewed consecutive cervical spine surgeries performed at the Israel Spine Center, Assuta Medical Center, during 2006 to 2013. Surgeries performed with neuromonitoring (transcranial-electric motor evoked potentials, somatosensory evoked potentials, electromyographic recordings) were included. Demographic data, medical history, findings at neurological examination and imaging, electrophysiological data recorded during surgery, and neurological outcomes were collected and analyzed.Three hundred eighty-one patients met inclusion criteria. Loss of potentials detected in nine patients during patient positioning and repositioning was undertaken with the aim of restoring electrophysiological signals. In 5/9 patients, repositioning resulted in immediate reappearance of potentials; in 1/5, potentials were affected again during decompression. In 4/9, repositioning did not immediately restore electrophysiological signals; in ¼, potentials reappeared later during the decompression and in ¾, potentials had not recovered till the conclusion of surgery. There were new neurological deficits in 2/9, including one patient with loss of potential that was not restored with repositioning and the one in whom potential was restored but lost again during decompression.Intraoperative neuro monitoring is an efficient tool to alert the surgical team to potential neurological damage. Head reposition often restores the electrophysiological signals with possible prevention of impending sequelae.

Background. Awake-craniotomy allows maximal tumor resection, which has been associated with extended survival. The feasibility and safety of awake-craniotomy and the effect of extent of resection on survival in the elderly population has not been established. The aim of this study was to compare surgical outcome of elderly patients undergoing awake-craniotomy to that of younger patients. Methods. Outcomes of consecutive patients younger and older than 65 years who underwent awake-craniotomy at a single institution between 2003 and 2010 were retrospectively reviewed. The groups were compared for clinical variables and surgical outcome parameters, as well as overall survival. Results. A total of 334 young (45.4 ± 13.2 years, mean ± SD) and 90 elderly (71.7 ± 5.1 years) patients were studied. Distribution of gender, mannitol treatment, hemodynamic stability, and extent of tumor resection were similar. Significantly more younger patients had a better preoperative Karnofsky Performance Scale score ([70) than elderly patients (P = 0.0012). Older patients harbored significantly more high-grade gliomas (HGG) and brain metastases, and fewer low-grade gliomas (P \ 0.0001). No significantly higher rate of mortality, or complications were observed in the elderly group. Age was associated with increased length of stay (4.9 ± 6.3 vs. 6.6 ± 7.5 days, P = 0.01). Maximal extent of tumor resection in patients with HGG was associated with prolonged survival in the elderly patients. Conclusions. Awake-craniotomy is a well-tolerated and safe procedure, even in elderly patients. Gross total tumor resection in elderly patients with HGG was associated with prolonged survival. The data suggest that favorable prognostic factors for patients with malignant brain tumors are also valid in elderly patients.

Object Preserving motor function is a major challenge in surgery for intraaxial brain tumors. Navigation systems are unreliable in predicting the location of the corticospinal tracts (CSTs) because of brain shift and the inability of current intraoperative systems to produce reliable diffusion tensor imaging data. The authors describe their experience with elaborate neurophysiological assessment and tractography-based navigation, corrected in real time by 3D intraoperative ultrasonography (IOUS) to identify motor pathways during subcortical tumor resection. Methods A retrospective analysis was conducted in 55 patients undergoing resection of tumors located within or in proximity to the CSTs at the authors' institution between November 2007 and June 2009. Corticospinal tract tractography was coregistered to surgical navigation-derived images in 42 patients. Direct cortical-stimulated motor evoked potentials (dcMEPs) and subcortical-stimulated MEPs (scrtMEPs) were recorded intraoperatively to assess function and estimate the distance from the CSTs. Intraoperative ultrasonography updated the navigation imaging and estimated resection proximity to the CSTs. Preoperative clinical motor function was compared with postoperative outcome at several time points and correlated with incidences of intraoperative dcMEP alarm and low scrtMEP values. Results The threshold level needed to elicit scrtMEPs was plotted against the distance to the CSTs based on diffusion tensor imaging tractography after brain shift compensation with 3D IOUS, generating a trend line that demonstrated a linear order between these variables, and a relationship of 0.97 mA for every 1 mm of brain tissue distance from the CSTs. Clinically, 39 (71%) of 55 patients had no postoperative deficits, and 9 of the remaining 16 improved to baseline function within 1 month. Seven patients had varying degrees of permanent motor deficits. Subcortical stimulation was applied in 45 of the procedures. The status of 32 patients did not deteriorate postoperatively (stable or improved motor status): 27 of them (84%) displayed minimum scrtMEP thresholds > 7 mA. Six patients who experienced postoperative deterioration quickly recovered (within 5 days) and displayed minimum scrtMEP thresholds > 6.8 mA. Five of the 7 patients who had late (> 5 days postoperatively) or no recovery had minimal scrtMEP thresholds < 3 mA. An scrtMEP threshold of 3 mA was found to be the cutoff point below which irreversible disruption of CST integrity may be anticipated (sensitivity 83%, specificity 95%). Conclusions Combining elaborate neurophysiological assessment, tractography-based neuronavigation, and updated IOUS images provided accurate localization of the CSTs and enabled the safe resection of tumors approximating these tracts. This is the first attempt to evaluate the distance from the CSTs using the threshold of subcortical monopolar stimulation with real-time IOUS for the correction of brain shift. The linear correlation between the distance to the CSTs and the threshold of subcortical stimulation producing a motor response provides an intraoperative technique to better preserve motor function.

Object: The use of a supraorbital craniotomy as a minimally invasive neurosurgical technique to treat pathology located in the anterior cranial fossa and parasellar region is reported. Materials and Methods: 25 patients were operated upon using the supraorbital keyhole technique to expose various lesions located in the anterior skull base. Included were benign and malignant tumors, AVM, tuberculoma and trauma. Discussion and Conclusion: Utilizing small eyebrow incisions, a small supraorbital (keyhole) craniotomy, and microneurosurgical and/or endoscopically assisted access, allowed us to gain excellent optimal and safe exposure to a number of different pathologies of the anterior base and parasellar regions. The lesions were resected under complete control and with full preservation of surrounding neurovascular structures.

Intradural-extramedullary spinal cord tumor surgery is common. Unlike intramedullary spinal cord tumor surgery, where intraoperative neurophysiological monitoring (IONM) has been described extensively, the application of IONM has not been described in this context, and its relevance has not been investigated. From 2001 to 2012, 100 patients underwent intradural-extramedullary spinal cord tumor resection with IONM. Preoperative and postoperative clinical evaluations were completed retrospectively, using a modified McCormick grading scale and correlated with IONM monitorability and dynamics. IONM consisted of transcranial motor evoked potentials (tcMEP), spinal (D wave) and muscle generators, somatosensory evoked potentials (SSEP), and electromyography (EMG). Both short-term and long-term clinical evaluations were performed. Patient demographics, tumor type, span, location, and morphologic complexity were analyzed. Surgeries were performed for resection of schwannomas (33 %), meningiomas (22 %), ependymomas (12 %), and other pathologies (20 %); pathology was unknown in 13 % of patients. Tumor locations were cervical in 21 %, thoracic in 46 %, thoracolumbar in 7 %, lumbar 20 %, and not specified in 6 %. Tumors spanned an average of 2.2 spinal levels. Monitorability was 97 and 67 % with tcMEP and SSEP modalities respectively. D waves were monitorable in 73 % of attempts. Intraoperative tcMEP changes were reported in 29 cases with 14 resolved intraoperatively, There were one false-negative outcome and five true-positive outcomes. For SSEP, 13 changes were noted and three resolved; there were three false-negative results and one true-positive result. For D wave monitoring there were two intraoperative changes with none resolved leading to one false negative and one true positive result. With a multimodality approach incorporating any change in evoked potential, IONM demonstrated sensitivity of 0.82, specificity of 0.95, positive predictive value of 0.82, and a negative predictive value of 0.95. IONM is feasible and useful in the context of intradural-extramedullary spinal cord surgery for identifying iatrogenic injury to the spinal cord.

1. The blood-brain barrier (BBB) protects the brain from circulating xenobiotic agents. The pathophysiology, time span, spatial pattern, and pathophysiological consequences of BBB disruptions are not known. 2. Here, we report the quantification of BBB disruption by measuring enhancement levels in computerized tomography brain images. 3. Pathological diffuse enhancement associated with elevated albumin levels in the cerebrospinal fluid (CSF) was observed in the cerebral cortex of 28 out of 43 patients, but not in controls. Four patients displayed weeks-long focal BBB impairment. In 19 other patients, BBB disruption was significantly associated with elevated blood pressure, body temperature, serum cortisol, and stress-associated CSF 'readthrough" acetylcholinesterase. Multielectrode electroencephalography revealed enhanced slow-wave activities in areas of focal BBB disruption. Thus, quantification of BBB disruption using minimally invasive procedures, demonstrated correlations with molecular, clinical, and physiological stress-associated indices. 4. These sequelae accompany a wide range of neurological disorders, suggesting that persistent, detrimental BBB disruption is considerably more frequent than previously assumed.

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).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 low-grade ependymomas.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.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.

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).We defined IUGR as birth weight10th 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.We enrolled 14 infants with IUGR (mean GA, 34.3 ± 1.8 weeks; mean birth weight 1486 ± 304 g) and 16 appropriate for GA controls (mean GA, 33.7 ± 2 weeks; mean birth weight, 1978 ± 488 g). There were no significant between-group differences in perinatal complications. The mean aEEG trace width was 20.8 ± 1.4 μv in the infants with IUGR versus 17.3 ± 1.6 μv 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 (r = -0.8; P = .001 for infants with IUGR and r = -0.9; P.001 for controls). The Lacey Assessment of the Preterm Infant developmental score was significantly lower in the infants with IUGR (P.02) and was correlated with aEEG trace width (r = -0.6; P = .002) and with delta activity (r = -0.5; P = .02).Preterm infants with IUGR have delayed EEG maturation associated with delayed neuromotor development. The predictive value of these alterations regarding developmental deficits associated with IUGR remains undetermined, however.

BACKGROUND Awake craniotomy (AC) for removal of intra-axial brain tumors is a well-established procedure. However, the occurrence and consequences of intraoperative seizures during AC have not been well characterized. OBJECTIVE To analyze the incidence, risk factors, and consequences of seizures during AC. METHODS The database of AC at Tel Aviv Medical Center between 2003 to 2011 was reviewed. Occurrences of intraoperative seizures were analyzed with respect to medical history, medications, tumor characteristics, and postoperative outcome. RESULTS Of the 549 ACs performed during the index period, 477 with complete records were identified. Sixty patients (12.6%) experienced intraoperative seizures. The AC procedure failed in 11 patients (2.3%) due to seizures. Patients with intraoperative seizures were significantly younger than nonseizing patients (45 ± 14 years vs 52 ± 16 years, P = .003), had a higher incidence of frontal lobe involvement (86% vs % 57%, P < .0001), and had higher prevalence of a history of seizures (P = .008). Short-term motor deterioration developed postoperatively in a higher percentage of patients with intraoperative seizures (20% vs 10.1%, P = .02) with a longer hospitalization period (4.0 ± 3.0 days vs 3.0 ± 3.0 days, P = .045). CONCLUSION Although in most cases intraoperative seizures will not result in AC failure, the surgical team should be prepared to treat them promptly to avoid intractable seizures. Intraoperative seizures are more common in younger patients with a tumor in the frontal lobe and those with a history of seizures. Moreover, they are associated with a higher incidence of transient postoperative motor deterioration and protracted length of hospital stay.

OBJECTIVE Preoperative embolization is performed before spine tumor surgery when significant intraoperative hemorrhage is anticipated. Occlusion of radicular and segmental arteries may result in spinal ischemia. The goal of this study was to check whether neurophysiological monitoring during preoperative angiography in patients scheduled for total en bloc spondylectomy (TES) of spine tumors improves the safety of vessel occlusion. METHODS This was a case series study of patients who underwent tumor embolization under somatosensory evoked potential (SSEP) and motor evoked potential (MEP) monitoring in preparation for TES in treating spine tumors. The angiography findings, the embolized vessels, and the results are presented. RESULTS Five patients whose ages ranged from 33 to 75 years and who had thoracic spine tumors are reported. Four patients suffered from primary tumor and 1 patient had a metastatic tumor. Radicular arteries at the tumor level, 1 level above, and 1 level below were permanently occluded when SSEPs and MEPs were preserved during temporary occlusion. No complications were encountered during or after the angiography procedure and embolization. CONCLUSIONS Temporary occlusion with electrophysiological monitoring during preoperative angiography may improve the safety of permanent radicular artery occlusion, including the artery of Adamkiewicz in patients undergoing TES for the treatment of spine tumors.

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 (>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.

Awake craniotomy for removal of intraaxial tumors within or adjacent to eloquent brain regions is a well-established procedure. However, awake craniotomy failures have not been well characterized. In the present study, the authors aimed to analyze and assess the incidence and causes for failed awake craniotomy.The database of awake craniotomies performed at Tel Aviv Medical Center between 2003 and 2010 was reviewed. Awake craniotomy was considered a failure if conversion to general anesthesia was required, or if adequate mapping or monitoring could not have been achieved.Of 488 patients undergoing awake craniotomy, 424 were identified as having complete medical, operative, and anesthesiology records. The awake craniotomies performed in 27 (6.4%) of these 424 patients were considered failures. The main causes of failure were lack of intraoperative communication with the patient (n = 18 [4.2%]) and/or intraoperative seizures (n = 9 [2.1%]). Preoperative mixed dysphasia (p0.001) and treatment with phenytoin (p = 0.0019) were related to failure due to lack of communication. History of seizures (p = 0.03) and treatment with multiple antiepileptic drugs (p = 0.0012) were found to be related to failure due to intraoperative seizures. Compared with the successful awake craniotomy group, a significantly lower rate of gross-total resection was achieved (83% vs 54%, p = 0.008), there was a higher incidence of short-term speech deterioration postoperatively (6.1% vs 23.5%, p = 0.0017) as well as at 3 months postoperatively (2.3% vs 15.4%, p = 0.0002), and the hospitalization period was longer (4.9 ± 6.2 days vs 8.0 ± 10.1 days, p0.001). Significantly more major complications occurred in the failure group (4 [14.8%] of 27) than in the successful group (16 [4%] of 397) (p = 0.037).Failures of awake craniotomy were associated with a lower incidence of gross-total resection and increased postoperative morbidity. The majority of awake craniotomy failures were preventable by adequate patient selection and avoiding side effects of drugs administered during surgery.

Antiphospholipid antibody (APLA) syndrome is a major risk factor for arterial and venous thrombosis. Surgical risks in patients known to suffer from APLA syndrome are usually related to haemorrhage or to thrombo-embolic events, such as deep venous thrombosis and pulmonary emboli. The rare published reports of patients with APLA syndrome undergoing neurosurgical procedures relate to haemostatic complication, with none alerting to the peri-operative risk of stroke in these patients. We present a case of a peri-operative stroke in a patient undergoing resection of a foramen magnum meningioma. We discuss the association of peri-operative stroke and APLA syndrome and emphasize the high risk it imposes for neurosurgical procedures in these patients. In addition, we suggest an anticoagulation treatment algorithm for APLA syndrome patients undergoing craniotomies.

Dear Editor, We would like to present an interesting case of postoperative hematomyelia following resection of an intramedullary spinal cord tumor (IMSCT) and discuss its clinical implications. Hematomyelia is a relatively rare phenomenon. Hematomyelia is mostly associated with traumatic insult, spinal vascular malformations such as intramedullary cavernous malformations [3, 10], or anticoagulation therapy [1, 9]. Clinical presentation varies from acute onset of spinal neurological deficits, accompanied by severe back or radicular pain, to chronic, slowly progressing neurological decline. A slow clinical course is usually associated with better prognosis [7]. Hematomyelia is a known presenting sign of spinal cord tumors [8]. It is also a rarely described complication of IMSCT surgery [2, 5]. Our patient was a 32-year-old male with a history of lung sarcoidosis presented with progressive sensorymotor disturbances of the lower limbs. MRI demonstrated multifocal pial lesions with a large intramedullary lesion at T6-7. Following rapid worsening of motor functions, he was operated upon. A subtotal resection of the lesion was performed. Pathology was consistent with low-grade glial tumor with pilocytic features. Following the first surgery, weakness on the right side improved. Eighteen months after surgery, a further decline in motor function was noticed. MRI demonstrated marked growth of the remnant tumor with homogenous enhancement and subependymal spread evident up to C6-7. The patient experienced rapid motor deterioration and underwent a second operation. A very generous subtotal re-resection was performed. Throughout the surgery, MEP and SSEP potentials monitoring remained uneventful. At the conclusion of surgery, the spinal cord was free of pressure with absolute hemostasis, and displayed pulsation and free CSF flow. Immediately following surgery the patient felt well, with evident motor improvement. However, on postoperative day 2 the patient attempted to get up from his bed unassisted and collapsed. A family member lifted the patient back to his bed. A few hours later the patient began suffering from severe back pain. In the following hours, the patient developed almost complete quadriplegia with minimal distal left hand movements. An emergency MRI revealed massive hematomyelia from the tumor site at T7 ascending all the way up to the foramen magnum (Fig. 1). A decision not to operate was made. The patient was intubated and transferred to the NICU. He underwent a tracheostomy, and over the next few weeks regained motor function in the upper limbs. The patient remains paraplegic however. B. Shofty : J. Roth :A. Korn : S. Constantini (*) Department of Pediatric Neurosurgery, Tel-Aviv Medical Center, 6th Weizman St., Tel-Aviv, Israel e-mail: sconsts@netvision.net.il

Introduction Selective dorsal rhizotomy (SDR) is commonly guided by an intraoperative pathoelectrophysiologic response (IPR) to electrical stimulation of posterior rootlets. The rootlets guided partial transection leads to reduced spasticity postoperatively. Prior studies have shown a statistically significant correlation between the extent of IPR and the preoperative degree of lower extremity GMFM (gross motor function measure) as well as postoperative improvement. Studies have also shown cognitive function (CF) improvement in patients who have undergone SDR, yet it is unknown whether this is a direct or indirect effect of the spasticity reduction. No study has investigated the correlation between IPR and cognitive function.The goal of this study was to answer the question: is there a direct correlation between the extent of IPR and postoperative CF improvement?. Material and methods 11 children with baseline GMFCS 3–5 underwent SDR directed by IPR (5 female, 6 male, age range 3–10 years).IPR severity was classified according to a Modified Phillips & Parks scale (1–6). The CF included communication skills, speech, eye contact, and caregiver’s evaluation. CF Data was stratified by a 3 degree scale (normal, abnormal, absent). The change in each function was scored on a 5 degree score, (−2)–(+2). Intraoperatively, rootlets displaying any degree of IPR were transected unless motor sphincter innervation was evident. The degree and extent of IPR and transaction were correlated with cognitive parameters. Results 177 IPR rootlets were transected. 91% of patients showed CF improvement after SDR. At this time, no specific direct correlation was found between IPR and CF improvement, including specific CF components: eye contact, speech, communication and caregiver’s evaluation. This could be due to small sample size and nearly global CF improvement. Conclusion Cognitive improvement after SDR is a common and consistent finding that needs to be further investigated. Presently, IPR cannot be shown to be a marker for CF changes post-SDR.