Management of intractable chronic cough during awake craniotomy: illustrative case

BACKGROUND Chronic cough is a common but challenging clinical condition that can adversely affect the safety of awake surgical endeavors such as awake craniotomy (AC). This case lesson highlighted a patient with severe refractory chronic cough undergoing AC for resection of a recurrent left frontal, insula, anterior temporal anaplastic ependymoma of the eloquent cortex. OBSERVATIONS The patient was successfully managed using a multifaceted medical treatment regimen combined with preoperative and intraoperative cough suppression therapy with a speech-language pathologist. The patient coughed only once intraoperatively and had a positive outcome. LESSONS Chronic cough is often multifactorial and requires a multifaceted treatment approach. Despite this challenge, select patients can successfully be navigated through AC with appropriate treatment for their condition. A review of neurogenic cough and modern treatments, which were used in this patient and would be helpful to neurologists or neurosurgeons, are also discussed.

Intraoperative localization and preservation of reading in ventral occipitotemporal cortex

Resective surgery in language-dominant ventral occipitotemporal cortex (vOTC) carries the risk of causing impairment to reading. As it is not on the lateral surface, it is not easily accessible for intraoperative mapping and extensive stimulation mapping can be time consuming. Here we assess the feasibility of using task-based electrocorticography (ECoG) recordings intraoperatively to help guide stimulation mapping of reading in vOTC. In 11 patients undergoing extraoperative, intracranial seizure mapping we recorded induced broadband gamma activation (70 - 150 Hz) during a visual category localizer. Word-responsive cortex localized in this manner showed a high sensitivity (72%) to stimulation-induced reading deficits, and the confluence of ECoG and stimulation positive sites appears to demarcate the visual word form area. In two additional patients, with pathologies necessitating resections in language-dominant vOTC, task-based functional mapping was performed intraoperatively using subdural ECoG, alongside direct cortical stimulation. Cortical areas critical for reading were mapped and successfully preserved, while enabling pathological tissue to be completely removed. Data collection is possible in <3 minutes and initial intraoperative data analysis takes <3 minutes, allowing for rapid assessment of broad areas of cortex. Eloquent cortex in ventral visual cortex can be rapidly mapped intraoperatively using ECoG. This method acts to guide high-probability targets for stimulation, with limited patient participation, and can be used to avoid iatrogenic dyslexia following surgery.

SURG-09. SUCCESSFUL SAFETY AND EFFICACY OF GAMMATILE INTRACRANIAL BRACHYTHERAPY IMPLANTED DURING AWAKE CRANIOTOMY

INTRODUCTION GammaTile intracranial brachytherapy utilizing cesium-131 seeds has demonstrated encouraging safety and local control results in a single-arm precommercial study, and recently received Food and Drug Administration clearance. The authors report the first case of GammaTile intraoperative brachytherapy performed during an awake craniotomy. METHODS A 50-year-old man suffered a generalized tonic-clonic seizure while a vehicle passenger. MRI revealed a 2.8 cm left lateral frontal lesion nearing his Broca’s area. Open brain biopsy revealed IDH-wildtype MGMT unmethylated GBM. Unfortunately, despite several interventions (awake craniotomy, adjuvant chemoradiation with temozolomide, Avastin, tumor treating fields) he suffered tumor progression near the left parietal resection cavity. Due to the location of this tumor, re-resection was planned with awake craniotomy and language mapping. A preoperative planning session involving Radiation Oncology and Neurosurgery identified the area of the expected postoperative bed, and consequently five GammaTiles were ordered, each containing 4 cesium-131 3.5 U seeds. RESULTS During surgery, once the tumor was mapped, bipolar stimulation was performed while the patient spoke in complete sentences until going into speech arrest on the posterior edge of the gyrus, indicative of language cortex. Following this mapping, microsurgical maximal safe resection occurred, after which areas at risk for tumor residual/recurrence were determined in consultation with Radiation Oncology. Subsequently, Neurosurgery placed all five GammaTiles (20 cesium-131 seeds total) in customized forward fashion to optimally cover the dosimetric needs of these areas. Following GammaTile placement, closure was completed and radioactive surveys of the room remained within state statue. Postoperative dosimetry yielded excellent coverage, and speech function was maintained. CONCLUSIONS The first reported case of GammaTile intraoperative brachytherapy during awake craniotomy supports the safety and feasibility of this treatment strategy. This case indicates that for patients with tumors adjacent to eloquent cortex, awake craniotomy can allow for maximum safe resection and implantation of intraoperative brachytherapy.

Pathological Investigation of Meningioma Capsule with respect to Tumor Cell Invasion

OBJECTIVE No previous study has pathologically investigated whether the meningioma capsule presents with tumor cells. We investigated which types of tumor capsules include tumor cells to help decide the kind of capsules which can be left intraoperatively without recurrence risk. METHODS We investigated 22 specimens of 14 newly diagnosed meningiomas between February 2011 and June 2021. Capsules were classified into three types: tumor capsule (TC), capsule-like thickened arachnoid membrane (CAM), and extended membrane (EM). Capsule properties were scored as hardness (soft = 1, medium = 2, hard = 3) and transparency (high = 1, medium = 2, low = 3). Hardness, transparency, and score sum was compared between capsules with/without tumor invasion in CAM and EM types. RESULTS The mean follow-up duration was 28.1 months, and there was only one recurrence in a remote location from the residual capsule. Nine capsules were classified as TC, seven as CAM, and six as EM. 88.9% of TCs, 42.9% of CAMs, and 50% of EMs were invaded by tumor cells. Hardness, transparency, and score sum in CAM with tumor invasion was lower than in CAM without, but not significant (p = 0.114, p = 0.114, p = 0.057). CONCLUSION Thickened TC or soft and highly transparent CAM imply a high risk of tumor cell invasion, thus such cases should be followed up long and carefully. The hard and low transparent residual CAMs may have low risk of tumor invasion, thus these kinds of residual capsules might not increase the recurrence risk. Thus, leaving such capsules tightly adhered to the eloquent cortex is theoretically justified to avoid damaging the brain surface.

Awake craniotomy for a low-grade glioma - a pilot procedure at a public hospital in Trinidad and Tobago

Awake craniotomies (AC) are proven to reduce the neurological deficit associated with tumour resection in areas of eloquent cortex. Successful performance requires not only technical skill, but the availability of neuronavigation, cortical mapping, intra-operative frozen section and the appropriate anaesthetic support. This case report describes the first fully awake craniotomy done in Trinidad, at a public hospital, for a patient with seizures secondary to a low-grade glioma. It resulted in an excellent patient outcome, with full cessation of seizures and no postoperative deficits.

Intraoperative seizures occurrence in cortical mapping of eloquent areas

The effect of structural epilepsy on the frequency of intraoperative convulsive seizures is assessed when mapping functionally significant areas of the cerebral cortex during resection of intracerebral neoplasms. The work is based on the analysis of the results of intraoperative neurophysiological studies at the Polenov Neurosurgical Institute. For the period 20192020 87 intraoperative mappings of eloquent cortex were carried out during resections of intracerebral neoplasms: 79 mappings of the motor cortex and 16 mappings of auditory-speech areas during operations with awakening. When mapping the motor zones of the cortex, the frequency of seizures was 5.1%, while mapping the auditory-speech zones with awakening 18.75%. The division of cases of intraoperative convulsive seizures into two groups: seizures arising from motor mapping and seizures associated with the mapping of auditory zones reflects differences in factors that affect the excitability of the cerebral cortex. In motor mapping, stimulation occurs against the background of general anesthesia, unlike waking operations. The intensity of stimulation in auditory mapping is higher than in motor mapping in motor mapping. Formally, the current used in motor mapping is significantly higher than in mapping auditory zones. In general, with the development of intraoperative convulsive seizures, the current intensity of cortical stimulation does not exceed the average values required to stimulate functionally significant cortical zones. The presence of epileptic syndrome in patients with intracerebral tumors cannot be considered as a predictor of intraoperative seizure development when performing motor mapping under general anesthesia as well as during surgery with awakening for mapping of motor or auditory verbal zones.

Awake craniotomy for glioblastoma in COVID-19–positive patients and delivering the standard of care: illustrative case

BACKGROUND Providing the standard of care to patients with glioblastoma (GBM) during the novel coronavirus of 2019 (COVID-19) pandemic is a challenge, particularly if a patient tests positive for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Further difficulties occur in eloquent cortex tumors because awake speech mapping can theoretically aerosolize viral particles and expose staff. Moreover, microscopic neurosurgery has become difficult because the use of airborne-level personal protective equipment (PPE) crowds the space between the surgeon and the eyepiece. However, delivering substandard care will inevitably lead to disease progression and poor outcomes. OBSERVATIONS A 60-year-old man with a left insular and frontal operculum GBM was found to be COVID-19 positive. Treatment was postponed pending a negative SARS-CoV-2 result, but in the interim, he developed intratumoral hemorrhage with progressive expressive aphasia. Because the tumor was causing dominant hemisphere language symptomatology, an awake craniotomy was the recommended surgical approach. With the use of airborne-level PPE and a surgical drape to protect the surgeon from the direction of potential aerosolization, near-total gross resection was achieved. LESSONS Delaying the treatment of patients with GBM who test positive for COVID-19 will lead to further neurological deterioration. Optimal and timely treatment such as awake speech mapping for COVID-19–positive patients with GBM can be provided safely.

Indications for Inpatient Magnetoencephalography in Children – An Institution’s Experience

Magnetoencephalography (MEG) is recognized as a valuable non-invasive clinical method for localization of the epileptogenic zone and critical functional areas, as part of a pre-surgical evaluation for patients with pharmaco-resistant epilepsy. MEG is also useful in localizing functional areas as part of pre-surgical planning for tumor resection. MEG is usually performed in an outpatient setting, as one part of an evaluation that can include a variety of other testing modalities including 3-Tesla MRI and inpatient video-electroencephalography monitoring. In some clinical circumstances, however, completion of the MEG as an inpatient can provide crucial ictal or interictal localization data during an ongoing inpatient evaluation, in order to expedite medical or surgical planning. Despite well-established clinical indications for performing MEG in general, there are no current reports that discuss indications or considerations for completion of MEG on an inpatient basis. We conducted a retrospective institutional review of all pediatric MEGs performed between January 2012 and December 2020, and identified 34 cases where MEG was completed as an inpatient. We then reviewed all relevant medical records to determine clinical history, all associated diagnostic procedures, and subsequent treatment plans including epilepsy surgery and post-surgical outcomes. In doing so, we were able to identify five indications for completing the MEG on an inpatient basis: (1) super-refractory status epilepticus (SRSE), (2) intractable epilepsy with frequent electroclinical seizures, and/or frequent or repeated episodes of status epilepticus, (3) intractable epilepsy with infrequent epileptiform discharges on EEG or outpatient MEG, or other special circumstances necessitating inpatient monitoring for successful and safe MEG data acquisition, (4) MEG mapping of eloquent cortex or interictal spike localization in the setting of tumor resection or other urgent neurosurgical intervention, and (5) international or long-distance patients, where outpatient MEG is not possible or practical. MEG contributed to surgical decision-making in the majority of our cases (32 of 34). Our clinical experience suggests that MEG should be considered on an inpatient basis in certain clinical circumstances, where MEG data can provide essential information regarding the localization of epileptogenic activity or eloquent cortex, and be used to develop a treatment plan for surgical management of children with complicated or intractable epilepsy.

Surgically treatable adult epilepsy: a changing patient population. Experience from a level 4 epilepsy center

OBJECTIVE Invasive monitoring has long been utilized in the evaluation of patients for epilepsy surgery, providing localizing information to guide resection. Stereoelectroencephalography (SEEG) was introduced at the authors’ level 4 epilepsy surgery program in 2013, with responsive neurostimulation (RNS) becoming available the following year. The authors sought to characterize patient demographics and epilepsy-related variables before and after SEEG introduction to understand whether differences emerged in their patient population. This information will be useful in understanding how SEEG, possibly in conjunction with RNS availability, may have changed practice patterns over time. METHODS This is a retrospective cohort study of consecutive patients who underwent surgery for epilepsy from 2006 to 2018, comprising 7 years before and 5 years after the introduction of SEEG. The authors performed univariate analyses of patient characteristics and outcomes and used generalized estimating equations logistic regression for predictive analysis. RESULTS A total of 178 patients were analyzed, with 109 patients in the pre-SEEG cohort and 69 patients in the post-SEEG cohort. In the post-SEEG cohort, more patients underwent invasive monitoring for suspected bilateral seizure onsets (40.6% vs 22.0%, p = 0.01) and extratemporal seizure onsets (68.1% vs 8.3%, p < 0.0001). The post-SEEG cohort had a higher proportion of patients with seizures arising from eloquent cortex (14.5% vs 0.9%, p < 0.001). Twelve patients underwent RNS insertion in the post-SEEG group versus none in the pre-SEEG group. Fewer patients underwent resection in the post-SEEG group (55.1% vs 96.3%, p < 0.0001), but there was no significant difference in rates of seizure freedom between cohorts for those patients having undergone a follow-up resection (53.1% vs 59.8%, p = 0.44). CONCLUSIONS These findings demonstrate that more patients with suspected bilateral, eloquent, or extratemporal epilepsy underwent invasive monitoring after adoption of SEEG. This shift occurred coincident with the adoption of RNS, both of which likely contributed to increased patient complexity. The authors conclude that their practice now considers invasive monitoring for patients who likely would not previously have been candidates for surgical investigation and subsequent intervention.