A Large Facial Nerve Schwannoma Presenting as a Swelling in Parotid Region-A Rare Case Report

Extratemporal facial nerve schwannomas are rare entity. Pre-operative assessment is mostly inconclusive with differential diagnosis of parotid tumors. We hereby report a case of 28 years female who presented with painless swelling in right parotid region with normal facial nerve function. Ultrasonography was suggestive well circumscribed and homogenous mass arising from the deep lobe of parotid gland. The Fine-needle aspiration cytology came out to be inconclusive. For further characterization of the tumor contrast enhanced MR imaging was performed. The MR imaging revealed well-defined cystic, heterogeneous, pear-shaped mass lesion situated near the stylomastoid foramen. Post operatively the mass came out to be schwannoma on histopathological examination.

Value of semiology in predicting epileptogenic zone and surgical outcome following frontal lobe epilepsy surgery

OBJECTIVE

To evaluate the ability of semiology alone in localising the epileptogenic zone (EZ) in people with frontal lobe epilepsy (FLE) who underwent resective surgery.

METHODS

We examined data on all individuals who had FLE surgery at our centre between January 01, 2011 and December 31, 2020. Descriptions of ictal semiology were obtained from video-EEG telemetry reports and presurgical multidisciplinary meeting summaries. The putative EZ was represented by the final site of resection. We assessed how well initial and combined set-of-semiologies correlated anatomically with the EZ, using a semiology visualisation tool to generate probabilistic cortical heatmaps of involvement in seizures.

RESULTS

Sixty-one individuals had FLE surgery over the study period. Twelve months following surgery, 28/61 (46%) were completely seizure-free, with a further eight experiencing only auras. Comparing the semiology database with the putative EZ, combined set-of-semiology correctly lateralised in 77% (95% CI: 69-85%), localised to the frontal lobe in 57% (95% CI: 48-67%), frontal lobe subregions in 52% (95% CI: 43-62%), and frontal gyri in 25% (95% CI: 16-33%). No difference in degree of correlation was seen comparing those with ongoing seizures 12 months after surgery to those seizure free.

SIGNIFICANCE

Semiology alone was able to correctly lateralize the putative EZ in 77%, and localise to a sublobar level in approximately half of individuals who had FLE surgery. Semiology is not adequate alone and must be combined with imaging and EEG data to identify the epileptogenic zone.

Long-term seizure, psychiatric and socioeconomic outcomes after frontal lobe epilepsy surgery

OBJECTIVE

Resective surgery for selected individuals with frontal lobe epilepsy can be effective, although multimodal outcomes are less established than in temporal lobe epilepsy. We describe long-term seizure remission and relapse patterns, psychiatric comorbidity, and socioeconomic outcomes following frontal lobe epilepsy surgery.

METHODS

We reviewed individual data on frontal lobe epilepsy procedures at our center between 1990 and 2020. This included the presurgical evaluation, operative details and annual postoperative seizure and psychiatric outcomes, prospectively recorded in an epilepsy surgery database. Outcome predictors were subjected to multivariable analysis, and rates of seizure freedom were analyzed using Kaplan-Meier methods. We used longitudinal assessment of the Index of Multiple Deprivation to assess change in socioeconomic status over time.

RESULTS

A total of 122 individuals with a median follow-up of seven years were included. Of these, 33 (27 %) had complete seizure freedom following surgery, with a further 13 (11 %) having only auras. Focal MRI abnormality, histopathology (focal cortical dysplasia, cavernoma or dysembryoplastic neuronal epithelial tumor) and fewer anti-seizure medications at the time of surgery were predictive of a favorable outcome; 67 % of those seizure-free for the first 12 months after surgery never experienced a seizure relapse. Thirty-one of 50 who had preoperative psychiatric pathology noticed improved psychiatric symptomatology by two years postoperatively. New psychiatric comorbidity was diagnosed in 15 (13 %). Persistent motor complications occurred in 5 % and dysphasia in 2 %. No significant change in socioeconomic deciles of deprivation was observed after surgery.

SIGNIFICANCE

Favorable long-term seizure, psychiatric and socioeconomic outcomes can be seen following frontal lobe epilepsy surgery. This is a safe and effective treatment that should be offered to suitable individuals early.

Neuropathological spectrum of drug resistant epilepsy: 15-years-experience from a tertiary care centre

Neuropathology of drug resistant epilepsy (DRE) has direct bearing on the clinical outcome. Classification of the most common pathologies, hippocampal sclerosis (HS) and focal cortical dysplasia (FCD) have undergone several revisions and studies on the surgical pathology of DRE employing the updated ILAE classification are scarce. Here, we report the neuropathological spectrum of 482 surgically treated cases of DRE from a single institute using the latest ILAE classifications along with clinicoradiologic correlation. Majority of the cases (324, 67.2%) had temporal lobe epilepsy (TLE), with 158 (32.8%) having extratemporal seizure focus. Among TLE, HS was most common (n = 208, 64.2%), followed by neoplasms (42, 13%), FCD (26, 8%) and dual pathology (23, 7%). Less frequent were vascular malformations (cavernoma-3, arteriovenous malformation-1), mild malformation of cortical development (mMCD, 3), gliotic lesions (5), cysticercosis (2), double pathology (2) and polymicrogyria (1). Among extratemporal epilepsies, FCD was most common (46, 29.1%), followed by neoplasms (29, 18.3%), gliotic lesions (27, 17.1%), Rasmussen encephalitis (18, 11.4%), hypothalamic hamartoma (12, 7.6%), malformations of cortical development (10, 6.3%) and vascular malformations (6, 3.8%). Less frequent were double pathology (2, cysticercosis + FCD type IIb, DNET + FCD type IIb), mMCD (2), cysticercosis (1) and dual pathology (1). No underlying pathology was detected in 12 cases (2.5%). Radiopathological concordance was noted in 83%. In 36 cases (7.5%), histopathology detected an unsuspected second pathology that included FCD type III (n = 16) dual pathology (n = 18) and double pathology (n = 2). Further, in four MRI negative cases, histopathology was required for a conclusive diagnosis.

Network connectivity separate from the hypothesized irritative zone correlates with impaired cognition and higher rates of seizure recurrence

INTRODUCTION

Surgery remains an essential option for the treatment of medically intractable temporal lobe epilepsy (TLE). However, only 66% of patients achieve postoperative seizure freedom, perhaps attributable to an incomplete understanding of brain network alterations in surgical candidates. Here, we applied a novel network modeling algorithm and measured key characteristics of epileptic networks correlated with surgical outcomes and objective measures of cognition.

METHODS

Twenty-two patients were prospectively included, and relevant demographic information was attained. Resting state functional magnetic resonance imaging (rsfMRI) and electroencephalography (EEG) data were recorded and preprocessed. Using our novel algorithm, patient-specific epileptic networks were mapped preoperatively, and geographic spread was quantified. Global functional connectivity was also determined using a volumetric functional atlas. Neuropsychological pre- and postsurgical raw and standardized scores obtained blinded to epileptic network status. Key demographic data and features of epileptic networks were then correlated with surgical outcome using Pearson's product-moment correlation.

RESULTS

At an average follow-up of 18.4 months, 15/22 (68%) patients were seizure-free. Connectivity was measured globally using a functional 3D atlas. Higher mean global connectivity correlated with worse scores in preoperative neuropsychological testing of executive functioning (Ruff Figural Fluency Test [RFFT]-ER; R = 0.943, p = 0.005). A higher ratio of highly correlated connections between regions of interest (ROIs) in the hemisphere contralateral to the seizure onset correlated with impairment in executive functioning (RFFT-ER; R = 0.943, p = 0.005). Higher numbers of highly correlated connections between ROIs in the contralateral hemisphere correlated with impairment in both short- and long-term measures of verbal memory (Rey Auditory Verbal Learning Test Trials 6, 7 [RAVLT6, RAVLT7]; R = -0.650, p = 0.020, R = -0.676, p = 0.030). Epilepsy networks were modeled in each patient, and localization of the epilepsy network in the bitemporal lobes correlated with lower scores in neuropsychological tests measuring verbal learning and short-term memory (RAVLT6; R = -0.671, p = 0.024). Higher rates of seizure recurrence correlated with localization of the epilepsy network bitemporally (R = -0.542, p = 0.014), with the stronger correlation found with localization to the contralateral temporal lobe from side of surgery (R = - 0.530, p = 0.016).

CONCLUSION

Increased connectivity contralateral to seizure onset and epilepsy network spread in the bitemporal lobes correlated with lower measures of executive functioning and verbal memory. Epilepsy network localization to the bitemporal lobes, in particular, the contralateral temporal lobe, is associated with higher rates of seizure recurrence. These findings may reflect network-level disruption that has infiltrated the contralateral hemisphere and the bitemporal lobes contributing to impaired cognition and relatively worse surgical outcomes. Further identification of network parameters that predict patient outcomes may aid in patient selection, resection planning, and ultimately the efficacy of epilepsy surgery.

The oxymoron of image-guided resection in 3 T MRI-negative extratemporal epilepsy: Technique and postoperative results

OBJECTIVE

We share our experience with extratemporal MRI-negative epilepsies that received "image-guided" resection with the use of neuronavigation after invasive presurgical video-EEG monitoring. We describe and discuss our technique of image generation, navigation system registration, and surgical resection. In addition, we evaluate seizure outcome with respect to the preoperatively planned versus achieved resection.

PATIENTS AND METHODS

Seven patients with 3 T MRI-negative extratemporal epilepsy received navigation-guided resective surgery. The resection plan was based on electrophysiological data from intracranial EEG recordings. For each case a resection segment was created in the neuronavigation device in a systematic manner. We compared the preoperatively planned segment to the achieved resection and looked for correlation with postoperative seizure outcome according to Engel classification, at last follow-up (mean 2.4 years, range 1-4 years).

RESULTS

Mean volume of planned resections was 23.8 ± 15.3 cm³ and of achieved resections 17 ± 10.4 cm³. There was complete overlap with planned resection in 4 patients and partial overlap in 3. Postoperative seizure outcome was class I in 4 patients (57%), IIIA in 1 patient and IVB in 2 patients. Three patients reached seizure-freedom (Engel IA). Volume of planned resection, volume difference of planned versus achieved resection and level of overlap (complete versus partial) did not significantly correlate to seizure outcome.

CONCLUSION

The use of neuronavigation for planning and executing a tailored resection in MRI-negative extratemporal epilepsy is elaborate but can be an effective procedure.

Extratemporal resections in pediatric epilepsy surgery-an overview

Despite optimized medical treatment, approximately one third of all patients with epilepsy continue to have seizures and by definition have medically resistant epilepsy (MRE). For these patients, surgical disruption of the epileptogenic network may enable freedom or great improvement in control of their seizures. The success of surgery is dependent on accurate localization of the epileptogenic zone and network. Epilepsy arising from regions of cortical dysplasia within the neocortex of the frontal, parietal, and occipital lobes show a propensity for reorganization and progressive decline in seizure freedom and consequent poorer surgical outcome. These procedures often require staged investigation with intracranial electrodes via subdural grids or stereoelectroencephalography (SEEG) and are considered extratemporal resections (ETRs). Central concepts include the following: (1) localization of epileptogenic and eloquent functional regions, (2) safe and effective placement of intracranial electrode arrays, (3) resection of epileptogenic cortex, and (4) avoidance of complications. Each of these concepts is summarized and developed in this summary paper.

Increased segregation of brain networks in focal epilepsy: An fMRI graph theory finding

Focal epilepsy is conceived of as activating local areas of the brain as well as engaging regional brain networks. Graph theory represents a powerful quantitative framework for investigation of brain networks. Here we investigate whether functional network changes are present in extratemporal focal epilepsy.

Task-free functional magnetic resonance imaging data from 15 subjects with extratemporal epilepsy and 26 age and gender matched healthy controls were used for analysis. Local network properties were calculated using local efficiency, clustering coefficient and modularity metrics. Global network properties were assessed with global efficiency and betweenness centrality metrics. Cost-efficiency of the networks at both local and global levels was evaluated by estimating the physical distance between functionally connected nodes, in addition to the overall numbers of connections in the network.

Clustering coefficient, local efficiency and modularity were significantly higher in individuals with focal epilepsy than healthy control subjects, while global efficiency and betweenness centrality were not significantly different between the two groups. Local network properties were also highly efficient, at low cost, in focal epilepsy subjects compared to healthy controls.

Our results show that functional networks in focal epilepsy are altered in a way that the nodes of the network are more isolated. We postulate that network regularity, or segregation of the nodes of the networks, may be an adaptation that inhibits the conversion of the interictal state to seizures. It remains possible that this may be part of the epileptogenic process or an effect of medications.

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Focal epilepsy is a neurological disorder known to affect neural networks.

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We examine fMRI network changes during rest in extratemporal epilepsy patients.

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Extratemporal epilepsy subjects show increased (isolated) local network regularity.

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Network isolation may represent a ‘seizure-protection’ mechanism in focal epilepsy.

Long-term outcome and predictors of resective surgery prognosis in patients with refractory extratemporal epilepsy

PURPOSE

We analyzed the long-term postoperative outcome and possible predictive factors of the outcome in surgically treated patients with refractory extratemporal epilepsy.

METHODS

We retrospectively analyzed 73 patients who had undergone resective surgery at the Epilepsy Center Brno between 1995 and 2010 and who had reached at least 1 year outcome after the surgery. The average age at surgery was 28.3±11.4 years. Magnetic resonance imaging (MRI) did not reveal any lesion in 24 patients (32.9%). Surgical outcome was assessed annually using Engel's modified classification until 5 years after surgery and at the latest follow-up visit.

RESULTS

Following the surgery, Engel Class I outcome was found in 52.1% of patients after 1 year, in 55.0% after 5 years, and in 50.7% at the last follow-up visit (average 6.15±3.84 years). Of the patients who reached the 5-year follow-up visit (average of the last follow-up 9.23 years), 37.5% were classified as Engel IA at each follow-up visit. Tumorous etiology and lesions seen in preoperative MRI were associated with significantly better outcome (p=0.035; p<0.01). Postoperatively, 9.6% patients had permanent neurological deficits.

CONCLUSION

Surgical treatment of refractory extratemporal epilepsy is an effective procedure. The presence of a visible MRI-detected lesion and tumorous etiology is associated with significantly better outcome than the absence of MRI-detected lesion or other etiology.

Temporal and pontine involvement in a case of herpes simplex encephalitis, presenting as kluver bucy syndrome - a case report

Bilateral temporal and frontal lobe involvement is a common characteristic of herpes simplex encephalitis (HSE). Clinical sequelae of herpes simplex encephalitis may manifest sometimes as Kluver Bucy syndrome (KBS). In herpes simplex encephalitis, apart from frontal lobe, extra temporal involvement is rare and uncommon. We report a case of HSE manifesting clinically as KBS with a rare radiological finding of temporal and extratemporal involvement of pons.

A review of facial nerve anatomy

An intimate knowledge of facial nerve anatomy is critical to avoid its inadvertent injury during rhytidectomy, parotidectomy, maxillofacial fracture reduction, and almost any surgery of the head and neck. Injury to the frontal and marginal mandibular branches of the facial nerve in particular can lead to obvious clinical deficits, and areas where these nerves are particularly susceptible to injury have been designated danger zones by previous authors. Assessment of facial nerve function is not limited to its extratemporal anatomy, however, as many clinical deficits originate within its intratemporal and intracranial components. Similarly, the facial nerve cannot be considered an exclusively motor nerve given its contributions to taste, auricular sensation, sympathetic input to the middle meningeal artery, and parasympathetic innervation to the lacrimal, submandibular, and sublingual glands. The constellation of deficits resulting from facial nerve injury is correlated with its complex anatomy to help establish the level of injury, predict recovery, and guide surgical management.