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Lumbar synovial cysts (LSCs) can cause painful radiculopathy and sensory and/or motor deficits. Historically, first-line surgical treatment has been decompression with fusion. Recently, minimally invasive laminectomy without fusion has shown equal or superior results to traditional decompression and fusion methods.This study investigates the long-term efficacy of minimally invasive laminectomy without fusion in the treatment of LSC as it relates to the rate of subsequent fusion surgery.A retrospective review was performed over a 10-year period of patients undergoing minimally invasive laminectomy for symptomatic LSCs. The primary end point was the rate of revision surgery requiring fusion.Eighty-five patients with symptomatic LSCs underwent minimally invasive laminectomy alone January 2010-August 2020 at our institution. The most common location was L4-5 (72%). Preoperative imaging identified spondylolisthesis (grade 1) in 43 patients (57%), none of which was unstable on available dynamic radiographs. Average procedure duration was 93 minutes, with 78% of patients discharged home on the same day of surgery. Over 46 months of mean follow-up, 17 patients (20%) required 19 revision operations. Of those operations, 16 were spinal fusions (17.6%). Median time to fusion surgery was 36 months. There were no identifiable risk factors on multivariate regression analysis that predicted the need for fusion.Minimally invasive laminectomy is an effective first-line treatment for symptomatic LSCs and avoids the need for fusion in most treated patients. Of our patients, 18% required a fusion over 46 months, suggesting that further studies are required to guide patient selection.

OBJECTIVE Single-position lateral lumbar interbody fusion (SP-LLIF) has recently gained significant popularity due to increased operative efficiency, but it remains technically challenging. Robot-assisted percutaneous pedicle screw (RA-PPS) placement can facilitate screw placement in the lateral position. The authors have reported their initial experience with SP-LLIF with RA-PPS placement in the lateral position, and they have compared this accuracy with that of RA-PPS placement in the prone position. METHODS The authors reviewed prospectively collected data from their first 100 lateral-position RA-PPSs. The authors graded screw accuracy on CT and compared it to the accuracy of all prone-position RA-PPS procedures during the same time period. The authors analyzed the effect of several demographic and perioperative metrics, as a whole and specifically for lateral-position RA-PPS placement. RESULTS The authors placed 99 lateral-position RA-PPSs by using the ExcelsiusGPS robotic platform in the first 18 consecutive patients who underwent SP-LLIF with postoperative CT imaging; these patients were compared with 346 prone-position RA-PPSs that were placed in the first consecutive 64 patients during the same time period. All screws were placed at L1 to S1. Overall, the lateral group had 14 breaches (14.1%) and the prone group had 25 breaches (7.2%) (p = 0.032). The lateral group had 5 breaches (5.1%) greater than 2 mm (grade C or worse), and the prone group had 4 (1.2%) (p = 0.015). The operative level had an effect on the breach rate, with breach rates (grade C or worse) of 7.1% at L3 and 2.8% at L4. Most breaches were grade B (< 2 mm) and lateral, and no breach had clinical sequelae or required revision. Within the lateral group, multivariate regression analysis demonstrated that BMI and number of levels affected accuracy, but the side that was positioned up or down did not. CONCLUSIONS RA-PPSs can improve the feasibility of SP-LLIF. Spine surgeons should be cautious and selective with this technique owing to decreased accuracy in the lateral position, particularly in obese patients. Further studies should compare SP-LLIF techniques performed while the patient is in the prone and lateral positions.

Intradural spinal cord pathologies have traditionally been managed with open surgical procedures and require the completion of a durotomy. Minimally invasive techniques are emerging as alternative procedures with the goal of reducing complications, but often require specialized equipment with additional training.We conduct a single institution retrospective review from 2016 to 2019 of patients undergoing minimally invasive durotomy closure for intradural extramedullary pathologies using a novel technique that utilizes standard operating room equipment. This cohort is compared to a cohort of patients treated with a traditional open approach.Patients treated with minimally invasive surgery (MIS) had no statistically significant differences in baseline characteristics compared to patients treated with open procedures. Patients treated with MIS had decreases in complication rates, estimated blood loss, and length of stay in the hospital compared to the patients treated with open procedures, but these differences did not reach levels of statistical significance.Our novel MIS technique for intradural extramedullary pathologies appears to be safe and effective in creating a watertight dural closure using standard operating room equipment, while avoiding the costs and training associated with specialized equipment and possibly improving surgical outcome measures when compared to open approaches.

Background Uncontrolled seizures in patients with gliomas have a significant impact on quality of life and morbidity, yet the mechanisms through which these tumors cause seizures remain unknown. Here, we hypothesize that the active metabolite d-2-hydroxyglutarate (d-2-HG) produced by the IDH-mutant enzyme leads to metabolic disruptions in surrounding cortical neurons that consequently promote seizures. Methods We use a complementary study of in vitro neuron-glial cultures and electrographically sorted human cortical tissue from patients with IDH-mutant gliomas to test this hypothesis. We utilize micro-electrode arrays for in vitro electrophysiological studies in combination with pharmacological manipulations and biochemical studies to better elucidate the impact of d-2-HG on cortical metabolism and neuronal spiking activity. Results We demonstrate that d-2-HG leads to increased neuronal spiking activity and promotes a distinct metabolic profile in surrounding neurons, evidenced by distinct metabolomic shifts and increased LDHA expression, as well as upregulation of mTOR signaling. The increases in neuronal activity are induced by mTOR activation and reversed with mTOR inhibition. Conclusion Together, our data suggest that metabolic disruptions in the surrounding cortex due to d-2-HG may be a driving event for epileptogenesis in patients with IDH-mutant gliomas.

Recent studies suggest that changes in neuronal metabolism are associated with epilepsy. High rates of ATP depletion, lactate dehydrogenase A and lactate production have all been found in epilepsy patients, animal and tissue culture models. As such, it can be hypothesized that chronic seizures lead to continuing elevations in neuronal energy demand which may lead to an adapted metabolic response and elevations of lactate dehydrogenase A. In this study, we examine elevations in the lactate dehydrogenase A protein as a long-term cellular adaptation to elevated metabolic demand from chronic neuronal activation. We investigate this cellular adaptation in human tissue samples and explore the mechanisms of lactate dehydrogenase A upregulation using cultured neurones treated with low Mg2+, a manipulation that leads to NMDA-mediated neuronal activation. We demonstrate that human epileptic tissue preferentially upregulates neuronal lactate dehydrogenase A, and that in neuronal cultures chronic and repeated elevations in neural activity lead to upregulation of neuronal lactate dehydrogenase A. Similar to states of hypoxia, this metabolic change occurs through the AMP-activated protein kinase/hypoxia-inducible factor-1α pathway. Our data therefore reveal a novel long-term bioenergetic adaptation that occurs in chronically activated neurones and provide a basis for understanding the interplay between metabolism and neural activity during epilepsy.

Unlike tandem stenosis of the cervical and lumbar spine, tandem cervical and thoracic stenosis (TCTS) of the spine is less common, and the approach and order of intervention are controversial. We aim to review the literature to evaluate the incidence and interventions for patients with cervical and thoracic stenosis. We provide illustrative cases to demonstrate that thoracic myelopathy in the setting of asymptomatic cervical stenosis can be treated safely. A systematic review of the literature through electronic databases of PubMed, EMBASE, Web of Science, and Cochrane Library was performed to present the current literature that evaluates TCTS as it relates to incidence and surgical interventions. We also present two cases of patients undergoing operative intervention for thoracic myelopathy in the setting of concurrent cervical stenosis. A total of 26 English original studies and case reports were identified. Nine studies evaluated the incidence of TCTS. 20 studies with a total of 168 patients with TCTS presented information on surgical intervention options. There is an overall aggregate incidence of 11.6% (530/4751) based on incidence studies. 165 patients underwent thoracic intervention. Of these patients, 63 patients underwent cervical intervention first, 29 underwent thoracic intervention first, and 73 underwent simultaneous, single-stage intervention. In patients presenting with myelopathy, both cervical and thoracic spine should be evaluated for TCTS. Order of operative intervention is tailored to clinical and radiographic information. In cases of thoracic myelopathy with asymptomatic cervical stenosis, thoracic intervention can be pursued with precautions to prevent further cervical cord injury.

Recent evidence favors a network concept in tuberous sclerosis (TSC) with seizure generation and propagation related to changes in global and regional connectivity between multiple, anatomically distant tubers. Direct exploration of network dynamics in TSC has been made possible through intracranial sampling with stereoelectroencephalography (sEEG). The objective of this study is to define epileptic networks in TSC using quantitative analysis of sEEG recordings. We also discuss the impact of the definition of these epileptic networks on surgical decision-making. Intracranial sEEG recordings were obtained from four pediatric patients who presented with medically refractory epilepsy secondary to TSC and subjected to quantitative signal analysis methods. Cortical connectivity was quantified by calculating pairwise coherence between all contacts and constructing an association matrix. The global coherence, defined as the ratio of the largest eigenvalue to the sum of all the eigenvalues, was calculated for each frequency band (delta, theta, alpha, beta, gamma). Spatial distribution of the connectivity was identified by plotting the leading principal component (product of the largest eigenvalue and its corresponding eigenvector). Four pediatric subjects with TSC underwent invasive intracranial monitoring with sEEG, comprising 31 depth electrodes and 250 contacts, for localization of the epileptogenic focus and guidance of subsequent surgical intervention. Quantitative connectivity analysis revealed a change in global coherence during the ictal period in the beta/low gamma (14–30 Hz) and high gamma (31–80 Hz) bands. Our results corroborate findings from existing literature, which implicate higher frequencies as a driver of synchrony and desynchrony. Coordinated high-frequency activity in the beta/low gamma and high gamma bands among spatially distant sEEG define the ictal period in TSC. This time-dependent change in global coherence demonstrates evidence for intra-tuberal and inter-tuberal connectivity in TSC. This observation has surgical implications. It suggests that targeting multiple tubers has a higher chance of seizure control as there is a higher chance of disrupting the epileptic network. The use of laser interstitial thermal therapy (LITT) allowed us to target multiple disparately located tubers in a minimally invasive manner with good seizure control outcomes.

Background Anterior cervical discectomy and fusion (ACDF) has conventionally been performed using an allograft cage with a plate-and-screw construct. Recently, standalone cages have gained popularity due to theorized decreases in operative time and postoperative dysphagia. Few studies have compared these outcomes. Here, we directly compare the outcomes of plated versus standalone ACDF constructs. Methods A single-center retrospective review of patients undergoing ACDF after June 2011 with at least 6 months of follow up was conducted. Clinical outcomes were analyzed and compared between standalone and plated constructs. Multivariate regression analysis of the primary outcome, need for revision surgery, as well as several secondary outcomes, procedure duration, estimated blood loss (EBL), length of hospital stay, disposition, and incidence of dysphagia, hoarseness, or surgical site infection, was completed. Results A total of 321 patients underwent ACDF and met inclusion-exclusion criteria, with mean follow-up duration of 20 months. Forty-six (14.3%) patients received standalone constructs, while 275 (85.7%) received plated constructs. Fourteen (4.4%) total revisions were necessary, 4 in the standalone group and 10 in the plated group, yielding revision rates of 8.7% and 3.6%, respectively (P = .125). Mean EBL was 98 mL in the standalone group and 63 mL in the plated group (P = .001). Mean procedure duration was 147 minutes in the standalone group and 151 minutes in the plated group (P = .800). Mean hospital stay was 3.6 days in the standalone group and 2.5 days in the plated group (P = .270). There was no significant difference in incidence of dysphagia (P = .700) or hoarseness (P = .700). Conclusions Standalone ACDF demonstrates higher, but not statistically significant, revision rates than plate-and-screw constructs, without the hypothesized decreased incidence of dysphagia or hoarseness and without decreased procedure duration or EBL. Surgeons may consider limiting use of these constructs to cases of adjacent segment disease. Larger studies with longer follow up are necessary to make more definitive conclusions. Level of Evidence 4. Clinical Relevance This study will help spine surgeons decide between using standalone or cage-and-plate constructs for ACDF.

Objective The true incidence of perioperative coronavirus disease 2019 (COVID-19) has not been well elucidated in neurosurgical studies. We reviewed the effects of the pandemic on the neurosurgical case volume to study the incidence of COVID-19 in patients undergoing these procedures during the perioperative period and compared the characteristics and outcomes of this group to those of patients without COVID-19. Methods The neurosurgical and neurointerventional procedures at 2 tertiary care centers during the pandemic were reviewed. The case volume, type, and acuity were compared to those during the same period in 2019. The perioperative COVID-19 tests and results were evaluated to obtain the incidence. The baseline characteristics, including a modified Medically Necessary Time Sensitive (mMeNTS) score, and outcome measures were compared between those with and without COVID-19. Results A total of 405 cases were reviewed, and a significant decrease was found in total spine, cervical spine, lumbar spine, and functional/pain cases. No significant differences were found in the number of cranial or neurointerventional cases. Of the 334 patients tested, 18 (5.4%) had tested positive for COVID-19. Five of these patients were diagnosed postoperatively. The mMeNTS score, complications, and case acuity were significantly different between the patients with and without COVID-19. Conclusion A small, but real, risk exists of perioperative COVID-19 in neurosurgical patients, and those patients have tended to have a greater complication rate. Use of the mMeNTS score might play a role in decision making for scheduling elective cases. Further studies are warranted to develop risk stratification and validate the incidence.

Background Posterior cervical fusion (PCF) is performed to treat cervical myelopathy, radiculopathy, and/or deformity. Constructs ending at the cervicothoracic junction (CTJ) may lead to higher rates of adjacent segment disease, and much debate exists regarding crossing the CTJ due to paucity of data in the literature. Objective To determine whether extension of PCF constructs across the CTJ decreases incidence of adjacent segment disease and need for revision surgery. Methods A single-center retrospective case series of patients undergoing multilevel PCFs since 2011 with at least 6-mo follow-up was conducted. Outcomes were analyzed and compared based on caudal extent of instrumentation via multivariate regression. Results A total of 149 patients underwent PCF, with a mean follow-up of 18.9 mo. A total of 15 (10.1%) revisions were performed, 7 (4.7%) of which were related to the construct. Five (8.3%) revisions were performed for constructs ending at C6, 1 (5.3%) at C7, 1 (2.6%) at T1, and none (0%) at T2 (P = .035). Mean procedure duration was 215 min at C6, 214 min at C7, 239 min at T1, and 343 min at T2 (P = .001). Mean estimated blood loss was 224 mL at C6, 178 mL at C7, 308 mL at T1, and 575 mL at T2 (P = .001). There was no difference in length of stay, disposition, surgical site infection, or radiographic parameters. Conclusion Extension of PCFs across the CTJ leads to lower early revision rates, but also to increased procedure duration and estimated blood loss. As such, decisions regarding caudal extent of instrumentation must weigh the risk of pseudarthrosis against that of longer procedures with higher blood loss.

BACKGROUND Stereoelectroencephalography (sEEG) using depth electrodes has become a mainstay of pediatric epilepsy surgery. This technique relies on rigid cranial fixation using skull pins, which forms the basis for accurate stereotactic navigation. The use of cranial fixation pins poses the threat of traumatic skull injuries in young children because of inadequate cranial bone thickness. OBJECTIVE To describe a rigid cranial fixation technique involving the integrated Gel Head Ring from the DORO QR3 multipurpose skull clamp set (Pro Med Instruments) with superimposed pin fixation in children below the age of 36 mo undergoing sEEG. METHODS Patients were placed in the supine position and the head was fixed using a DORO skull clamp with 3 pediatric cranial pins. The head was supported on the integrated Gel Head Ring, and a pin pressure of 20 pounds was applied. The DORO skull clamp set was then attached to the ROSA neurosurgical robot support telescopic arm for stereotactic navigation. RESULTS We present an illustrative series of 2 patients below the age of 3 yr with medically refractory epilepsy who underwent sEEG using our modified cranial fixation technique. Head position and reference registration were stable throughout the surgeries. Postoperative volumetric computed tomography scans of the head showed accurate placement of sEEG depth electrodes and did not reveal any fractures or epidural hematoma. No other complications related to cranial fixation were noted. CONCLUSION Concurrent use of rigid and nonrigid cranial fixation using the DORO skull clamp set provides safe and effective cranial fixation in infants and toddlers undergoing sEEG.

BACKGROUND Sacroiliac joint (SIJ) dysfunction can lead to significant pain and disability, greatly impairing quality of life. Arthrodesis may take up to 1 year to occur, after which revision can be considered. There is a need for highly accurate and reproducible techniques for revision that allow for purchase through undisturbed bone to prevent prolonged pain and disability. Moreover, a minimally invasive technique for revision would be favorable for recovery, particularly in elderly patients. OBSERVATIONS An 84-year-old man with a prior history of lumbar fusion presented with severe buttock pain limiting ambulation and sitting because of the failure of arthrodesis after SIJ fusion 1 year earlier. He underwent revision using a triangular titanium implant (TTI) in an S2-alar-iliac (S2-AI) trajectory under robotic guidance, which is a novel technique not yet described in the literature. The patient’s pain largely resolved, he was able to ambulate independently, and his quality of life improved tremendously. There were no complications of surgery. LESSONS Placement of a TTI using an S2-AI trajectory is a safe and effective method for revision that can be considered for elderly patients. Robot-assisted navigation can be used to facilitate an accurate and reproducible approach using a minimally invasive approach.

BACKGROUND Commercial magnetic resonance-guided laser interstitial thermal therapy (MRgLITT) systems utilize a generalized Arrhenius model to estimate the area of tissue damage based on the power and time of ablation. However, the reliability of these estimates in Vivo remains unclear. OBJECTIVE To determine the accuracy and precision of the thermal damage estimate (TDE) calculated by commercially available MRgLITT systems using the generalized Arrhenius model. METHODS A single-center retrospective review of pediatric patients undergoing MRgLITT for lesional epilepsy was performed. The area of each lesion was measured on both TDE and intraoperative postablation, postcontrast T1 magnetic resonance images using ImageJ. Lesions requiring multiple ablations were excluded. The strength of the correlation between TDE and postlesioning measurements was assessed via linear regression. RESULTS A total of 32 lesions were identified in 19 patients. After exclusion, 13 pairs were available for analysis. Linear regression demonstrated a strong correlation between estimated and actual ablation areas (R2 = .97, P

Endovascular thrombectomy has revolutionized the management of acute ischemic stroke from emergent large vessel occlusion. Continued technological advancement in the field, as evidenced by successive introduction of large bore aspiration catheters with enhanced trackability and large inner diameter, has played a major role in achieving fast and robust recanalization and improved clinical outcome. Here, we present three patients with intraprocedural device malfunction related to the JET 7 XTRA Flex reperfusion catheter.

Highlights • Intracranial hemorrhage occurs in COVID-19 patients with prolonged hospitalization. • SARS-CoV-2 binds to the endothelial lining of the cerebral vasculature via ACE-II. • Direct endothelial injury, pro-thrombotic states and DIC lead to hemorrhagic events. • We advocate heightened vigilance for intracerebral hemorrhage in COVID-19 patients., In this study, we report three cases of spontaneous intracranial hemorrhage in patients who were initially hospitalized at our tertiary care center in Washington, DC with symptoms of COVID-19. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection was diagnosed in all three patients, who were critically ill, requiring intubation and ventilatory support. During their protracted hospitalizations, subsequent imaging disclosed intracranial hemorrhages, including intracerebral and subarachnoid hemorrhages, in the context of anticoagulation and coagulopathy. We believe this is related to the tropism of SARS-CoV-2 to the endothelial lining of the cerebral vasculature via their angiotensin-converting enzyme (ACE) II receptors. Given our findings, we advocate heightened vigilance for intracerebral hemorrhage events, and scanning when practicable, in COVID-19 patients which have prolonged ventilatory support and depressed neurologic examinations.

Objective Percutaneous pedicle screws (PPS) are used to stabilize the spine after interbody fusion in minimally invasive approaches. Recently, robotic assistance has been developed to improve the accuracy of PPS. We report our initial experience with ExcelsiusGPS and compare its accuracy with our historical cohort of fluoroscopy-guided PPS. Methods We reviewed prospectively collected data from our first 100 robot-assisted PPS. We graded accuracy of screws on computed tomography imaging and compared it with a previous cohort of 90 PPS placed using fluoroscopy. We also analyzed the effect of various demographic and perioperative metrics on accuracy. Results We placed 103 PPS in the first 20 consecutive patients with postoperative computed tomography imaging using ExcelsiusGPS. All screws were placed at L2 to S1. Our robot-assisted cohort had 6 breaches, with only 2 breaches >2 mm, yielding an overall breach rate of 5.8% and a significant breach rate of 1.9%. In comparison, our fluoroscopy-guided cohort had a breach rate of 3.3% and a significant breach rate of 1.1%, which was not significantly different. More breaches occurred in the first half of cases, suggesting a learning curve with robotic assistance. No demographic or perioperative metrics had a significant effect on accuracy. Conclusions Our breach rates with ExcelsiusGPS were low and consistent with others reported in the literature, as well as with other robotic systems. Our series shows equivalent accuracy of placement of PPS with this robotic platform compared with fluoroscopic guidance and suggests a relatively short learning curve.

Deep brain stimulation (DBS) has traditionally been used to target the subthalamic nucleus (STN) or globus pallidus internus (GPi) to treat Parkinson’s disease (PD) and the ventral intermediate thalamic nucleus (VIM) to treat essential tremor (ET). Recent case reports have described targeting both the STN and VIM with a single trajectory and electrode to treat patients with tremor-dominant PD, yet outcome data for this procedure remains sparse. Our objective is to determine the safety and efficacy of combination STN-VIM DBS. We conducted a single-center retrospective case series of all patients who underwent combined STN-VIM DBS. Demographic, perioperative, and outcome data, including Unified Parkinson Disease Rating Scale-III (UPDRS) and tremor scores (OFF-medication), and levodopa equivalent daily dose (LEDD), were collected and analyzed. Nineteen patients underwent this procedure. Patients were 89% male and 11% female, with a mean age of 63.6 years. Mean preoperative UPDRS was 24.1, and LEDD was 811.8. At a mean follow-up of 33.8 months, UPDRS and LEDD decreased by an average of 9.2 (38.2%) and 326.3 (40.2%), respectively. Tremor scores decreased by 4.9 (59.0%), and 58% were able to decrease total medication burden. One patient developed transient left-sided weakness, yielding a complication rate of 5.3%. Combined targeting of STN and VIM thalamus via a single frontal trajectory for tremor-dominant Parkinson’s Disease results in similar UPDRS outcomes to STN DBS and improved control of tremor symptoms. Larger multicenter studies are necessary to validate this as the optimal DBS target for tremor-dominant PD.

To investigate the safety and efficacy of stereoelectroencephalography (sEEG) directed magnetic resonance-guided laser interstitial thermal therapy (MRgLITT) in medically refractory insular epilepsy in pediatric patients, define the relationship between ablation volumes and seizure control, and analyze the relationship between thermal energy and ablation volumes. A single-institution, retrospective review of pediatric patients with insular epilepsy who underwent sEEG directed MRgLITT over a 10-month period was performed. Perioperative, imaging, and outcome data were analyzed. Seizure outcomes were determined based on Engel score (Engel I versus Engel II–IV). Insula and ablation volumes were measured, and the proportion of insula volume ablated was calculated. Thermal energy was calculated in joules. Four patients underwent sEEG directed MRgLITT of insular epileptogenic foci. The ablation volume was higher in patients with Engel I outcome (3.93 cm3) compared to Engel II–IV outcome (1.02 cm3). The proportion of ablation to insula volume was lowest in patients with Engel II–IV outcome (25.09%). The mean energy requirement to create a unit volume of ablation in the insula is 1205.86 J. A linear trend was noted between thermal ablation energy and ablation volume (R2 = 0.884). Over a mean follow-up period of 104 days, three patients were seizure-free (Engel I), and one patient saw significant improvement in seizure frequency (Engel III). The proportion of insula ablated, as well as the volume of ablation, are related to seizure outcome with increasing ablation volumes corresponding to improved seizure control. Further analysis of insula laser ablation thermal dynamics and volumes is needed.

Background Pancreatic neuroendocrine tumors (pNETs) are known to frequently metastasize to the liver and lymphatics; however, metastasis to the spine is exceedingly rare. We report the first case of an intradural, extramedullary pNET metastasis to the upper cervical spine. Case Description A 75-year-old Hispanic male patient with history of stage IV pNET with metastasis to the liver and lymph nodes and new-onset lymphadenopathy seen on CT of the chest was found on positron emission tomography scan to have a lesion in the cervical spine. The patient was neurologically intact on physical examination, yet given the patient's medical history, magnetic resonance imaging of the cervical spine was performed, revealing a right-sided intradural, extramedullary mass at the C1–C2 level with associated mass effect on the spinal cord, likely representing a schwannoma. Due to the tumor size, mass effect, and the need for definitive tissue diagnosis, a partial C1–C2 laminectomy with intradural resection of the tumor was performed. The histology was consistent with the patient's known pNET. Conclusions As treatment for pNETs has evolved, there has been a surge in unique presentations of systemic well-differentiated pNETs being reported. It is vital that patients diagnosed with pNET be monitored for metastases, and when discovered, treated promptly.

Uncontrolled seizures in patients with low grade gliomas have a significant impact on quality of life and morbidity, yet the mechanisms through which these tumors cause seizures remain unknown. Albeit there are multiple features that contribute to tumor related epileptogenesis, IDH mutations are determined to be an independent factor, although the pathogenesis remains poorly understood. Here, we hypothesize that the active metabolite D-2-hydroxyglutarate (D-2-HG) produced by the IDH-mutant enzyme leads to metabolic disruptions in surrounding cortical neurons that consequently promote seizures. We use a complementary study of in vitro cortical cultures and electrographically sorted human cortical tissue from patients (n=5) with IDH-mutant gliomas to test this hypothesis. We demonstrate that D-2-HG leads to increased neuronal spiking activity (p< 0.0001) and promotes a distinct metabolic profile in surrounding neurons and upregulation of mTOR signaling (p< 0.0001), which is consistent in human epileptic cortex compared to peritumoral nonepileptic cortex. Furthermore, increases in neuronal activity are induced by mTOR activation and reversed with mTOR inhibition. Together, our data suggest that metabolic disruptions and mTOR signaling upregulation in the surrounding cortex due to D-2-HG may be a driving event for epileptogenesis in patients with IDH-mutant low grade gliomas.

Background: Smartphone applications (apps) are being increasingly utilized in the health care arena to improve patient care and outcomes. Objective: To further demonstrate the ability of a smartphone app to improve patient compliance with preoperative instructions and to decrease the number of last-minute surgery cancellations. Methods: Patients undergoing spine surgery were prospectively accrued. Smartphone app users were compared to non-app users. Patient adherence with preoperative instructions as well as last-minute surgery cancellations were analyzed. Results: All 85 app users adhered to preoperative instructions according to the acknowledgements sent to the web portal, and there were no cancelled surgeries. Among the 89 non-app users, there were five cancelled surgeries (5.6%). Conclusions: We demonstrate the ability of a smartphone application to improve patient adherence with preoperative instructions and decrease last-minute surgery cancellations.

Introduction: The insula presents anatomic challenges to surgical exploration and intervention. Open neurosurgical intervention is associated with high rates of complications despite improved seizure control. Minimally invasive techniques using novel energy delivery methods have gained popularity due to their relative safety and ability to overcome access-related barriers. The goal of this paper is to present an operative technical report and methodological considerations on the application of magnetic resonance-guided laser interstitial thermal therapy (MRgLITT) for the treatment of nonlesional, medically refractory, insular epilepsy in pediatric patients. Methods: Visualase laser probe(s) were implanted using ROSA robotic stereotactic guidance into the insula using a parasagittal trajectory. After confirmation of placement using intraoperative MRI, thermal energy was delivered under real-time MR guidance. Laser wire pullback was performed when the initial dose of thermal energy was insufficient to ablate the target in its entirety. Thermal ablation within the intended target was confirmed using gadolinium-enhanced brain MRI. Following removal of laser wires, a final T1-weighted axial brain MRI was performed to confirm no evidence of hemorrhage. Results: Three patients underwent MRgLITT of nonlesional insular epilepsy over an 11-month period. The epileptogenic focus was localized to the insula using stereoelectroencephalography. The anterior and middle portions of the insula were accessed using a parasagittal trajectory. Laser ablation was performed for up to 3 min using an output of 10.5 W. No complications were encountered, and all patients were discharged within 24 h after the surgery. At the most recent follow-up, all patients had an Engel I outcome without any new neurologic deficits. Conclusion: This small cohort shows that insular ablation can be achieved safely with promising seizure outcomes in the short term.

INTRODUCTION Epileptic seizures in patients with low-grade, isocitrate dehydrogenase (IDH) mutated gliomas reach 90%, a major source of morbidity for these patients. Albeit there are multiple features that contribute to tumor related epileptogenesis, IDH mutations are determined to be an independent factor, although the pathogenesis remains poorly understood. We demonstrate IDH-mutated tumors promote epileptogenesis through D-2-hydroxyglutarate (D-2-HG) dependent mTOR hyperactivation and metabolic reprogramming. METHODS Human epileptic and nonepileptic cortex were identified via subdural electrodes in patients with IDH-mutated gliomas (n=5). An in vitro rat cortical neuronal model on microelectrode arrays were utilized to investigate the role of D-2-HG on neuronal excitability. mTOR and lysine demethylase (KDM) modulators were applied to elucidate the epileptogenic mechanism. Tetrodotoxin was utilized to evaluate the contribution of neuronal activity to mTOR signaling and metabolism. mTOR signaling was evaluated through western blot analysis and multiplex immunofluorescence. Metabolic function were analyzed via Seahorse assays and metabolomic analysis. RESULTS D-2-HG increased normalized bursting rate in the neuronal cultures (p CONCLUSION We demonstrate IDH-mutated gliomas promote epileptogenesis through a D-2-HG dependent mTOR hyperactivation via KDM inhibition, a putative mechanism and potential therapeutic targets. Furthermore, we argue mTOR hyperactivation results in metabolic reprogramming, independent of neuronal firing, which may contribute to epileptogenesis, a heretofore unrecognized aspect of pathologic mTOR signaling in neurological diseases.

Ependymomas are the most common adult intramedullary spinal tumors. 1 Although uncommon in the brainstem, ependymomas make up a large proportion of tumors of this location. 2 , 3 , 4 , 5 , 6 , 7 , 8 We present an operative video case report of an intrinsic ependymoma at the cervicomedullary junction. The purpose of this report is to present the clinical picture, operative setup, and surgical technique involved in resection of an intramedullary tumor of this region. For best outcome for intramedullary ependymomas, the goal should be gross total resection. 1 , 9 , 10 These tumors have a relatively distinct plane between tumor and normal parenchyma, making a gross total resection more probable than cases of infiltrative intramedullary astrocytomas. 11 Despite this, significant morbidity can be associated with treatment. 1 Proper microsurgical technique with use of operative adjuncts can maximize resection while minimizing neurologic injury to optimize outcomes in patients. We present the case of a 42-year-old man presenting with neck and shoulder pain, upper extremity paresthesias, and gait instability. Magnetic resonance imaging of the neuroaxis revealed a heterogeneously enhancing expansile lesion in the lower medulla and multiple lesions in the thecal sac, representing drop metastases. Due to symptoms and mass effect from the lesion, the patient underwent a suboccipital craniotomy for tumor resection. We highlight operative techniques in our case, including use of neurophysiologic monitoring, intraoperative ultrasound, ultrasonic aspirator, and dissection with microcottonoid pledgets and bimanual technique. Pathology revealed a World Health Organization grade II ependymoma. Postoperative magnetic resonance imaging revealed a small amount of residual. He underwent full craniospinal proton beam therapy with boost to the residual and metastases with good outcome. Patient provided consent for this report.

Background Spondylolysis is a defect in the pars interarticularis that typically presents with axial back pain. Recently, minimally invasive spine techniques have increased in popularity and have been applied to the Buck technique of direct pars repair. Case Description In our series, 2 patients underwent minimally invasive direct pars repair by the percutaneous insertion of a cannulated lag screw across the pars defect with compression against the lamina. The defect was then decorticated and packed with bone grafting material through a tubular retractor. The clinical records, including preoperative imaging characteristics and intraoperative variables, were collected. The first patient was a 22-year-old woman with bilateral pars defects, and the second was a 21-year-old woman with a left-sided pars defect. They underwent minimally invasive direct pars repair without complications and were discharged home within 24–48 hours. In the first patient, the fusion was successful; however, the second experienced screw back out and required subsequent revision. The follow-up period was 25 months for patient 1 and 21 months for patient 2. The fracture morphology differed. The successfully repaired fractures were linear with smooth cortical edges and oriented perpendicular to the screw trajectory. The failed repair involved a unilateral, curved defect with comminuted cortical edges. Conclusion Minimally invasive direct pars repair can be performed safely and effectively with shortened hospital stays and reduced morbidity. Fracture morphology and orientation could be important predictors of the success of surgery.

OBJECTIVEStereoelectroencephalography (sEEG) and MR-guided laser interstitial thermal therapy (MRgLITT) have both emerged as minimally invasive alternatives to open surgery for the localization and treatment of medically refractory lesional epilepsy. Although some data are available about the use of these procedures individually, reports are almost nonexistent on their use in conjunction. The authors’ aim was to report early outcomes regarding efficacy and safety of sEEG followed by MRgLITT for localization and ablation of seizure foci in the pediatric population with medically refractory lesional epilepsy.METHODSA single-center retrospective review of pediatric patients who underwent sEEG followed by MRgLITT procedures was performed. Demographic, intraoperative, and outcome data were compiled and analyzed.RESULTSFour pediatric patients with 9 total lesions underwent sEEG followed by MRgLITT procedures between January and September 2017. The mean age at surgery was 10.75 (range 2–21) years. Two patients had tuberous sclerosis and 2 had focal cortical dysplasia. Methods of stereotaxy consisted of BrainLab VarioGuide and ROSA robotic guidance, with successful localization of seizure foci in all cases. The sEEG procedure length averaged 153 (range 67–235) minutes, with a mean of 6 (range 4–8) electrodes and 56 (range 18–84) contacts per patient. The MRgLITT procedure length averaged 223 (range 179–252) minutes. The mean duration of monitoring was 6 (range 4–8) days, and the mean total hospital stay was 8 (range 5–11) days. Over a mean follow-up duration of 9.3 (range 5.1–16) months, 3 patients were seizure free (Engel class I, 75%), and 1 patient saw significant improvement in seizure frequency (Engel class II, 25%). There were no complications.CONCLUSIONSThese early data demonstrate that sEEG followed by MRgLITT can be used safely and effectively to localize and ablate epileptogenic foci in a minimally invasive paradigm for treatment of medically refractory lesional epilepsy in pediatric populations. Continued collection of data with extended follow-up is needed.

Background Different diseases may occur within the same anatomic space and invade one another. Lesions of this nature are described as collision tumors. Collision tumors of the sella are rare, with pituitary adenoma-craniopharyngiomas having been described in only 15 cases. We discuss common and rare lesions of the sellar region, their neurodiagnostic qualities, and treatment considerations. Case Description We present the case of a 49-year-old woman presenting with symptoms of headache and blurred vision who underwent a 2-stage procedure and was found to have a craniopharyngioma and corticotrophic pituitary adenoma in collision. We review the literature on various combinations of sellar collision lesions, noting diagnostic and treatment considerations. Neuroimaging, intraoperative pathology, and histologic review help to provide optimum treatment when unusual conditions of the sella arise. Conclusions Many mechanisms for the development of collision lesions have been theorized, and further investigation may provide definitive answers regarding the origin of these neoplastic entities.

Synovial cysts of the lumbar spine result from degeneration of the facet capsule, and their prevalence may be as high as 10% in symptomatic patients. Although conservative management is possible, the majority of patients will require resection. Traditional procedures for resection use an ipsilateral approach requiring partial or complete resection of the ipsilateral facet complex, possibly leading to further destabilization. A contralateral technique using minimally invasive tubular retractors for synovial cyst resection avoids facet disruption, minimizes soft-tissue trauma, and limits disruption of the ligamentous and bony structures. Additionally, by approaching contralateral, the cyst/dura interface is better visualized especially at the depths of the lateral recess. Seeing the full extent of this interface from an ipsilateral approach is very difficult without decompressing the cyst, which, in turn, makes dissecting and separating the remaining cyst wall more difficult and increases the risk of durotomies.1,2 We report the case of a 53-yr-old female who presented with persistent left leg pain in an L5 distribution that was associated with some mild lower back pain. She was refractory to conservative management that included physical therapy along with a series of epidural steroid injections. She was noted to have some weakness with dorsiflexion on the left side and as absent a straight leg raise. Given the predominance of her leg over her back symptoms along with the patient's age, a minimally invasive contralateral approach for resection of the synovial cyst was offered as opposed to more traditional decompression and fusion. Institutional Review Board approval and patient consent for solitary case reports are not needed at our institution.

Introduction: MR-guided laser interstitial thermal therapy (MRgLITT) has emerged as a safe and effective treatment option for the ablation of epileptic foci. Its minimally invasive nature makes it attractive due to decreased morbidity and hospital stay. Objective: To report the efficacy and safety of MRgLITT as a minimally invasive procedure for the ablation of epileptic foci in the pediatric population of medically refractory lesional epilepsy. Methods: A retrospective review of patients who underwent MRgLITT via Visualase laser ablation at a single pediatric center was performed. Demographic and outcome data were compiled and analyzed. Results: Twelve pediatric patients with a total 18 lesions underwent MRgLITT procedures between December 2013 and September 2017. Mean age at surgery was 11.1 years. Surgical substrates included 4 hypothalamic hamartomas, 3 periventricular heterotopias, 2 deep focal cortical dysplasias, 2 tuberous sclerosis, and 1 mesial temporal sclerosis. Methods of stereotaxis used included Leksell frame, BrainLab VarioGuide, ROSA robot guidance, and ClearPoint navigation. Mean procedure length was 250 min, and mean length of stay was 1.3 days. After treatment, 8 patients were seizure free (Engel I, 66.7%), 2 patients demonstrated significant improvement (Engel II, 16.7%), and 2 patients showed worthwhile improvement (Engel III, 16.7%). One patient developed a left superior quadrantanopsia postoperatively. Mean follow-up duration was 10 months. Conclusion: This study contributes to the sparse literature in this field by demonstrating the high efficacy and low morbidity of MRgLITT as a minimally invasive method of ablation of epileptic foci in the pediatric population of medically refractory lesional epilepsy.

A 5-year old girl with congenital mitral and subaortic stenosis on anticoagulant therapy since her mechanical mitral valve replacement, and a remote history of idiopathic intrahepatic cholestasis requiring liver transplantation presented with jaundice and pruritus. She was found to have elevated transaminases, and an echocardiogram revealed significantly increased right ventricular pressures concerning for pulmonary hypertension. Subsequently, the patient needed to be intubated for respiratory insufficiency and poor cardiac output. After several days in the intensive care unit (ICU), she was noted to be bradycardic and have a dilated right pupil. A stat CT of the head demonstrated a …

Objective Tandem cervical and lumbar spinal stenosis (TSS) is classically described as intermittent claudication, gait disturbance, and clinical findings of mixed myelopathy and polyradiculopathy. Rarely, patients can present with TSS manifesting in isolated lumbar pain. Several reports have demonstrated improved lumbar back pain and radiculopathy after decompressive cervical spine procedures. We present six patients with dramatic resolution of lumbar spine related symptoms after decompression of the cervical spinal cord despite presenting solely with lower back complaints. Methods Clinical records of the senior author (F.A.S.) gathered from April 2006 to March 2013 were retrospectively reviewed identifying six patients presenting solely with lumbar symptoms and diagnosed with TSS based on history and physical examination. Results Six patients with a mean age of 55 (range 39 to 60) presented with solely lower back symptoms and clinical findings suspicious for TSS. Mean follow-up time for all patients was 12 months (range three to 27 months, median 11.5 months). Three patients underwent a cervical procedure as the principal operation, while the remainder had the lumbar spine decompressed initially. All patients that underwent a cervical procedure initially experienced a dramatic decrease or complete resolution of their preoperative lower back pain and radiculopathy (mean preoperative VAS of 6.7 vs. 3.7 postoperative). The remainder of patients with persistent lumbar symptoms resolved after a subsequent cervical operation. Conclusion Patients presenting with lumbar symptoms out of proportion to imaging require further investigation. We highlight the resolution of lumbar symptoms after a cervical procedure in a select group of patients presenting with lone lower back complaints. In patients presenting with symptoms disproportionate to lumbar imaging, treatment of cervical pathology may provide robust long-term relief of the initial lumbar-related presentation.