Citations

OBJECTIVEAlmost 30% of the patients with suspected temporal lobe epilepsy (TLE) have normal results on MRI. Success rates for resection of MRI-negative TLE are less favorable, ranging from 36% to 76%. Herein the authors describe the impact of intraoperative electrocorticography (ECoG) augmented by opioid activation and its effect on postoperative seizure outcome.METHODSAdult and pediatric patients with medically resistant MRI-negative TLE who underwent standardized ECoG at the time of their elective anterior temporal lobectomy (ATL) with amygdalohippocampectomy between 1990 and 2016 were included in this study. Seizure recurrence comprised the primary outcome of interest and was assessed using Kaplan-Meier and multivariable Cox regression analysis plots based on distribution of interictal epileptiform discharges (IEDs) recorded on scalp electroencephalography, baseline and opioid-induced IEDs on ECoG, and extent of resection.RESULTSOf the 1144 ATLs performed at the authors’ institution between 1990 and 2016, 127 (11.1%) patients (81 females) with MRI-negative TLE were eligible for this study. Patients with complete resection of tissue generating IED recorded on intraoperative ECoG were less likely to have seizure recurrence compared to those with incomplete resection on univariate analysis (p < 0.05). No difference was found in seizure recurrence between patients with bilateral independent IEDs and unilateral IEDs (p = 0.15), presence or absence of opioid-induced epileptiform activation (p = 0.61), or completeness of resection of tissue with opioid-induced IEDs on intraoperative ECoG (p = 0.41).CONCLUSIONSThe authors found that incomplete resection of IED-generating tissue on intraoperative ECoG was associated with an increased chance of seizure recurrence. However, they found that induction of epileptiform activity with intraoperative opioid activation did not provide useful intraoperative data predictive of improving operative results for temporal lobectomy in MRI-negative epilepsy.

Abstract BACKGROUND Erdheim-Chester disease (ECD) is a rare, non-Langerhans cell histiocytosis. Up to 50% of patients develop central nervous system involvement, and a subset of these patients can present with isolated tumor-like masses. OBJECTIVE To describe the skull base manifestations of ECD with an emphasis on aspects most pertinent to surgeons who may be referred such patients for primary evaluation. METHODS Scopus, Web of Science, and PubMed were searched from database inception to May 1, 2018 for articles reporting skull base ECD. An institutional retrospective analysis of all patients treated at the authors’ institution since January 1, 1996 was also performed to supplement these data. RESULTS Of 465 retrieved articles, 18 studies totaling 20 patients met inclusion criteria. Institutional review identified an additional 7 patients. Collectively, the median age at diagnosis was 49 yr (interquartile range, 42-58) with a 4:1 male-to-female ratio. Patients frequently presented with diplopia (48%), headache (30%), dysarthria (22%), and vertigo or imbalance (22%), though trigeminal hypesthesia (11%), facial nerve paresis (7%), hearing loss (7%), and trigeminal neuralgia (7%) were also observed. ECD commonly mimicked meningioma (33%), trigeminal schwannoma (8%), neurosarcoidosis (8%), and skull base lymphoma (8%). CONCLUSION Discrete skull base lesions frequently mimic more common pathology such as meningioma or cranial nerve schwannomas. Medical therapy comprises the initial treatment for symptomatic skull base disease. Surgical resection is not curative and the utility of surgical intervention is largely limited to biopsy to establish diagnosis and/or surgical debulking to relieve mass effect.

BackgroundOlfactory nerve fibers are at risk of injury during transnasal endoscopic skull‐base approaches. Olfactory outcomes for various techniques have not been thoroughly investigated. This study aims to report long‐term olfactory outcomes when a cold knife upper septal limb incision technique is used compared to monopolar cautery.MethodsA prospective cohort study was performed at a tertiary referral center. Adult patients undergoing endoscopic approaches with septal incisions were randomized to cold knife or monopolar cautery groups. Patient demographics, clinical history, surgical data, and outcomes were collected. Preoperative, 3‐month, and 12‐month postoperative scores on the University of Pennsylvania Smell Inventory Test (UPSIT) and 22‐item Sino‐Nasal Outcome Test (SNOT‐22) were measured. Fisher's exact tests were performed for categorical variables and t tests were performed for continuous variables.ResultsTwenty‐two (22) patients (10 cold knife, 12 cautery) were enrolled between March 2016 and August 2017. The average age ± standard deviation was 50.2 ± 14.0 years (p = 0.59), 54% (p = 0.69) were female, and the primary pathology was pituitary adenoma (73%, p = 1.00). Preoperative, 3‐month, and 12‐month postoperative UPSIT scores were similar between the cold knife and cautery groups (32.8 vs 32.4, p = 0.80; 33.1 vs 33.0, p = 0.96; 33.6 vs 33.3, p = 0.84). On the “sense of smell/taste” question of the SNOT‐22, there was also no difference at all time points (p > 0.22).ConclusionThere was no significant change in patient UPSIT scores 1 year after transnasal skull‐base approaches, and no short‐term or long‐term differences between cold knife and cautery upper septal limb incision techniques. Our study supports an individualized approach based on surgeon preference.

Background Age, tumor size and location, overall health, and patient preference are primary considerations driving treatment decision-making for intracranial meningiomas. However, even for the same individual patient, treatment recommendations may vary between centers and providers. Objective To study associations between geography, disease presentation, and management of intracranial meningioma in the United States. Methods The population-based Surveillance, Epidemiology, and End Results(SEER) data were queried between 2004 and 2014 for cases of intracranial meningioma. Results A total of 65,808 patients with intracranial meningioma were identified. Univariate analyses demonstrated strong associations between geographic location, age, and size of tumor at presentation. The mean age for all registries was 64.2 years, with a range from 62.0 (Utah registry) to 66.6 (Detroit registry). The greatest proportion of small tumors (<1 cm) were identified in the Utah registry (13.9% of tumors), while the greatest proportion of large tumors (> 4cm) were noted in the Hawaii registry (30.7% of tumors). Multivariable analysis demonstrated that the impact of geography on treatment selection was just as important as other established variables. For example, the distribution in tumor size between New Mexico and Greater California registries is nearly identical; however, the odds ratio for surgery was 1.5 times greater for the New Mexico population. Conclusion These data suggest that disease presentation and treatment are significantly influenced by regional referral patterns, provider or institutional treatment preferences, and regional availability of subspecialty expertise. Understanding such biases is important for patients, referring physicians, and treatment providers in an effort to provide balanced counseling and treatment.

Objective/Hypothesis The aim of the study was to determine the impact of race on disease presentation and treatment of intracranial meningioma in the United States. Study Design This study comprised of the analysis of a national population-based tumor registry. Methods Analysis of the surveillance, epidemiology, and end results (SEER) database was performed, including all patients identified with a diagnosis of intracranial meningioma. Associations between race, disease presentation, treatment strategy, and overall survival were analyzed in a univariate and multivariable model. Results A total of 65,973 patients with intracranial meningiomas were identified. Of these, 45,251 (68.6%) claimed white, 7,796 (12%) black, 7,154 (11%) Hispanic, 4,902 (7%) Asian, and 870 (1%) patients reported “other-unspecified” or “other-unknown.” The median annual incidence of disease was lowest among black (3.43 per 100,000 persons) and highest among white (9.52 per 100,000 persons) populations (p < 0.001). Overall, Hispanic patients were diagnosed at the youngest age and white patients were diagnosed at the oldest age (mean of 59 vs. 66 years, respectively; p < 0.001). Compared with white populations, black, Hispanic, and Asian populations were more likely to present with larger tumors (p < 0.001). After controlling for tumor size, age, and treatment center in a multivariable model, Hispanic patients were more likely to undergo surgery than white, black, and Asian populations. Black populations had the poorest disease specific and overall survival rates at 5 years following surgery compared with other groups. Conclusion Racial differences among patients with intracranial meningioma exist within the United States. Understanding these differences are of vital importance toward identifying potential differences in the biological basis of disease or alternatively inequalities in healthcare delivery or access Further studies are required to determine which factors drive differences in tumor size, age, annual disease incidence, and overall survival between races.

AbstractBackgroundPast research established that surgery plus adjuvant radiotherapy (S + AR) improves overall survival (OS) in esthesioneuroblastoma (ENB). However, it is unknown if the addition of adjuvant chemotherapy (AC) further improves survival. The primary objective of this study was to compare survival among patients treated with S + AR alone to patients who underwent S + AR + AC.MethodsRetrospective review of patient records.ResultsThirty‐eight patients met inclusion criteria for either S + AR or S + AR + AC treatment groups. The S + AR + AC group contained more patients with Kadish stage D disease, dural invasion, and positive histologic margins postsurgery. All S + AR + AC patients received platinum‐based regimens, combined with etoposide in 67%. OS and recurrence‐free survival did not differ between the two groups, even when restricting the analysis to patients with Kadish stages B and C disease.ConclusionPatients who received platinum‐based AC did not exhibit improved survival compared to S + AR alone. Further investigation, preferably prospective, into the optimal use of systemic therapy in ENB is warranted.

Introduction Optimal management of vestibular schwannoma (VS) demands involvement of an experienced multidisciplinary team. As the number of training programs in neurotology and skull base neurosurgery continues to rise, ensuring that trainees are capable of evidence-based decision-making and treatment, whether microsurgical or radiosurgical, is of paramount importance. The purpose of this study is to characterize the landscape of neurotologic and neurosurgical fellowship training programs in North America, with special reference to VS management. Methods A 64-item web-based survey assessing VS practice trends was devised by members of the North American Skull Base Society (NASBS) Research Task Force and distributed electronically to NASBS membership via SurveyMonkey as a cross-sectional study. Participation was entirely voluntary and there was no remuneration for survey completion. The survey link was active from November 29 to December 14, 2016. Results Of 719 members of the NASBS who were emailed a survey link, a total of 57 were returned (8%) completed surveys. Of all respondents, 51 (89%) claimed to have formal training in skull base neurosurgery or neurotology. Thirty-three respondents (65%) were skull base neurosurgeons while the remainder were neurotologists (n = 18; 35%). Institutions with fellowship programs tended to have a higher surgical, radiosurgical, and overall case volume than those with a residency program alone. However, 20% of respondents at institutions with fellowship programs reported evaluating less than 50 new diagnoses of VS per year and 12% reported a surgical case volume of less than 10 cases per year. Conclusion As the number of skull base training programs expands, it is our duty to ensure that trainees gain sufficient experience to enter independent practice with the ability to exercise informed decision-making and safely perform VS surgery and radiosurgery. In the current training climate, implementing multidisciplinary care models, formalized training requirements, and emerging surgical simulators will support the development of minimum proficiencies in VS care.

Background There is little data regarding postoperative outcomes of patients with obstructive sleep apnea (OSA) undergoing skull base surgery. The purpose of this study is to determine an association between risk factors and proximity of cerebrospinal fluid (CSF) leak to surgery in patients with OSA undergoing endoscopic skull base surgery. Methods A retrospective review of neurosurgical inpatients, with and without OSA, at a tertiary care institution from 2002 to 2015 that experienced a postoperative CSF leak after undergoing endoscopic skull base surgery. Results Forty patients met inclusion criteria, 12 (30%) with OSA. OSA patients had significantly higher body mass index (BMI; median 39.4 vs. 31.7, p < 0.01) and were more likely to have diabetes (41.7 vs. 10.7%, p = 0.04) than non-OSA patients; otherwise there were no significant differences in clinical comorbidities. No patients restarted positive pressure ventilation (PPV) in the inpatient setting. The type of repair was not a significant predictor of the time from surgery to leak. Patients with OSA experienced postoperative CSF leak 49% sooner than non-OSA patients (Hazard Ratio 1.49, median 2 vs. 6 days, log-rank p = 0.20). Conclusion Patients with OSA trended toward leaking earlier than those without OSA, and no OSA patients repaired with a nasoseptal flap (NSF) had a leak after postoperative day 5. Due to a small sample size this trend did not reach significance. Future studies will help to determine the appropriate timing for restarting PPV in this high risk population. This is important given PPV's significant benefit to the patient's overall health and its ability to lower intracranial pressure.

Abstract Objective This study investigates high‐frequency oscillations ( HFO s; 65–600 Hz) as a biomarker of epileptogenic brain and explores three barriers to their clinical translation: (1) Distinguishing pathological HFO s (path HFO ) from physiological HFO s (phys HFO ). (2) Classifying tissue under individual electrodes as epileptogenic (3) Reproducing results across laboratories. Methods We recorded HFO s using intracranial EEG ( iEEG ) in 90 patients with focal epilepsy and 11 patients without epilepsy. In nine patients with epilepsy putative phys HFO s were induced by cognitive or motor tasks. HFO s were identified using validated detectors. A support vector machine ( SVM ) using HFO features was developed to classify tissue under individual electrodes as normal or epileptogenic. Results There was significant overlap in the amplitude, frequency, and duration distributions for spontaneous phys HFO , task induced phys HFO , and path HFO , but the amplitudes of the path HFO were higher ( P < 0.0001). High gamma path HFO had the strongest association with seizure onset zone ( SOZ ), and were elevated on SOZ electrodes in 70% of epilepsy patients ( P < 0.0001). Failure to resect tissue generating high gamma path HFO was associated with poor outcomes ( P < 0.0001). A SVM classified individual electrodes as epileptogenic with 63.9% sensitivity and 73.7% specificity using SOZ as the target. Interpretation A broader range of interictal path HFO (65–600 Hz) than previously recognized are biomarkers of epileptogenic brain, and are associated with SOZ and surgical outcome. Classification of HFO s into physiological or pathological remains challenging. Classification of tissue under individual electrodes was demonstrated to be feasible. The open source data and algorithms provide a resource for future studies.

OBJECTIVE Deep brain stimulation (DBS) of the anterior nucleus of the thalamus (ANT) is a promising therapy for refractory epilepsy. Unfortunately, the variability in outcomes from ANT DBS is not fully understood. In this pilot study, the authors assess potential differences in functional connectivity related to the volume of tissue activated (VTA) in ANT DBS responders and nonresponders as a means for better understanding the mechanism of action and potentially improving DBS targeting. METHODS This retrospective analysis consisted of 6 patients who underwent ANT DBS for refractory epilepsy. Patients were classified as responders (n = 3) if their seizure frequency decreased by at least 50%. The DBS electrodes were localized postoperatively and VTAs were computationally generated based on DBS programming settings. VTAs were used as seed points for resting-state functional MRI connectivity analysis performed using a control dataset. Differences in cortical connectivity to the VTA were assessed between the responder and nonresponder groups. RESULTS The ANT DBS responders showed greater positive connectivity with the default mode network compared to nonresponders, including the posterior cingulate cortex, medial prefrontal cortex, inferior parietal lobule, and precuneus. Interestingly, there was also a consistent anticorrelation with the hippocampus seen in responders that was not present in nonresponders. CONCLUSIONS Based on their pilot study, the authors observed that successful ANT DBS in patients with epilepsy produces increased connectivity in the default mode network, which the authors hypothesize increases the threshold for seizure propagation. Additionally, an inhibitory effect on the hippocampus mediated through increased hippocampal γ-aminobutyric acid (GABA) concentration may contribute to seizure suppression. Future studies are planned to confirm these findings.