improving-outcomes-anteromesial-temporal-lobe-resections

Improving Outcomes in Anteromesial Temporal Lobe Resections - A Demonstration of Resecting the Temporal Piriform Cortex

Anteromesial temporal lobe resection (ATLR) is a useful treatment option for drug-resistant mesial temporal lobe epilepsy (DRmTLE). Growing evidence ...

University College London

National Hospital for Neurology and Neurosurgery

Temporary CSF diversion through an external ventricular drain (EVD) comes with the risk of EVD-related infections (ERIs). The incidence of ERIs varies from 0.8% to 22%. ERIs increase mortality, morbidity, length of stay, and costs; require prolonged courses of antibiotics; and increase the need for subsequent permanent CSF diversion. The authors report the results of a quality improvement project designed to improve infection rates and EVD placement using simulation training in addition to a standardized perioperative care bundle. This project resulted not only in a decrease in ERIs, but also a significant improvement in surgical outcomes.

Simulation workshops as an adjunct to perioperative care bundles in the management of external ventricular drains: improving surgical technique and reducing infection.

The accuracy of tunneled external ventricular drain (EVD) placement has been shown to be similar among practitioners of varying experience, but this has not yet been investigated for bolt EVDs. Tunneled and bolt EVDs are distinct techniques, and it is unclear if conclusions regarding accuracy can be inferred from one method to the other. The goal of this study was to determine whether neurosurgical experience influences the accuracy of bolt EVD placement.

Accuracy of bolt external ventricular drain insertion by neurosurgeons of different experience.

Individuals with temporal lobe epilepsy (TLE) may have significant language deficits. Language capabilities may further decline following temporal lobe resections. The language network, comprising dispersed gray matter regions interconnected with white matter fibers, may be atypical in individuals with TLE. This review explores the structural changes to the language network and the functional reorganization of language abilities in TLE. We discuss the importance of detailed reporting of patient's characteristics, such as, left- and right-sided focal epilepsies as well as lesional and nonlesional pathological subtypes. These factors can affect the healthy functioning of gray and/or white matter. Dysfunction of white matter and displacement of gray matter function could concurrently impact their ability, in turn, producing an interactive effect on typical language organization and function. Surgical intervention can result in impairment of function if the resection includes parts of this structure-function network that are critical to language. In addition, impairment may occur if language function has been reorganized and is included in a resection. Conversely, resection of an epileptogenic zone may be associated with recovery of cortical function and thus improvement in language function. We explore the abnormality of functional regions in a clinically applicable framework and highlight the differences in the underlying language network. Avoidance of language decline following surgical intervention may depend on tailored resections to avoid critical areas of gray matter and their white matter connections. Further work is required to elucidate the plasticity of the language network in TLE and to identify sub-types of language representation, both of which will be useful in planning surgery to spare language function.

Structure and function of language networks in temporal lobe epilepsy.

Drug-resistant focal epilepsy presents a significant morbidity burden globally, and epilepsy surgery has been shown to be an effective treatment modality. Therefore, accurate identification of the epileptogenic zone for surgery is crucial, and in those with unclear noninvasive data, stereoencephalography is required.

Previous, current, and future stereotactic EEG techniques for localising epileptic foci.

Anteromesial temporal lobe resection is the most common surgical technique used to treat drug-resistant mesial temporal lobe epilepsy, particularly when secondary to hippocampal sclerosis. Structural and functional imaging data suggest the importance of sparing the posterior hippocampus for minimising language and memory deficits. Recent work has challenged the view that maximal posterior hippocampal resection improves seizure outcome. This study was designed to assess whether resection of posterior hippocampal atrophy was associated with improved seizure outcome.

Hippocampal resection in temporal lobe epilepsy: Do we need to resect the tail?

In medically refractory temporal lobe epilepsy (TLE), 30%-50% of patients experience substantial language decline after resection in the language-dominant hemisphere. In this study, we investigated the contribution of white matter fiber bundle damage to language change at 3 and 12 months after surgery.

Contribution of White Matter Fiber Bundle Damage to Language Change After Surgery for Temporal Lobe Epilepsy.

Around 50% of patients undergoing frontal lobe surgery for focal drug-resistant epilepsy become seizure free post-operatively; however, only about 30% of patients remain seizure free in the long-term. Early seizure recurrence is likely to be caused by partial resection of the epileptogenic lesion, whilst delayed seizure recurrence can occur even if the epileptogenic lesion has been completely excised. This suggests a coexistent epileptogenic network facilitating ictogenesis in close or distant dormant epileptic foci. As thalamic and striatal dysregulation can support epileptogenesis and disconnection of cortico-thalamostriatal pathways through hemispherotomy or neuromodulation can improve seizure outcome regardless of focality, we hypothesize that projections from the striatum and the thalamus to the cortex may contribute to this common epileptogenic network. To this end, we retrospectively reviewed a series of 47 consecutive individuals who underwent surgery for drug-resistant frontal lobe epilepsy. We performed voxel-based and tractography disconnectome analyses to investigate shared patterns of disconnection associated with long-term seizure freedom. Seizure freedom after 3 and 5 years was independently associated with disconnection of the anterior thalamic radiation and anterior cortico-striatal projections. This was also confirmed in a subgroup of 29 patients with complete resections, suggesting these pathways may play a critical role in supporting the development of novel epileptic networks. Our study indicates that network dysfunction in frontal lobe epilepsy may extend beyond the resection and putative epileptogenic zone. This may be critical in the pathogenesis of delayed seizure recurrence as thalamic and striatal networks may promote epileptogenesis and disconnection may underpin long-term seizure freedom.

Thalamostriatal disconnection underpins long-term seizure freedom in frontal lobe epilepsy surgery.

A greater extent of resection of the temporal portion of the piriform cortex (PC) has been shown to be associated with higher likelihood of seizure freedom in adults undergoing anterior temporal lobe resection (ATLR) for drug-resistant temporal lobe epilepsy (TLE). There have been no such studies in children, therefore this study aimed to investigate this association in a pediatric cohort.

Extent of piriform cortex resection in children with temporal lobe epilepsy.

Computer-assisted planning (CAP) allows faster SEEG planning and improves grey matter sampling, orthogonal drilling angles to the skull, reduces risk scores and minimises intracerebral electrode length. Incorporating prior SEEG trajectories enhances CAP planning, refining output with centre-specific practices. This study significantly expands on the previous work, compares priors libraries between two centres, and describes differences between SEEG in adults and children in these centres.

Refining computer-assisted SEEG planning with spatial priors - A novel comparison of implantation strategies across adult and paediatric centres.

This study aims to refine computer-assisted planning (CAP) of SEEG implantations by adding spatial constraints from prior SEEG trajectories ("Priors") to improve safety and reduce manual adjustments, without increasing planning time.

Article	Year
Simulation workshops as an adjunct to perioperative care bundles in the management of external ventricular drains: improving surgical technique and reducing infection. Journal of neurosurgery\| PubMed ID: 30497209	2019
Accuracy of bolt external ventricular drain insertion by neurosurgeons of different experience. Acta neurochirurgica\| PubMed ID: 33479814	2021
Structure and function of language networks in temporal lobe epilepsy. Epilepsia\| PubMed ID: 35184291	2022
Previous, current, and future stereotactic EEG techniques for localising epileptic foci. Expert review of medical devices\| PubMed ID: 36003028	2022
Hippocampal resection in temporal lobe epilepsy: Do we need to resect the tail? Epilepsy research\| PubMed ID: 36709527	2023
Contribution of White Matter Fiber Bundle Damage to Language Change After Surgery for Temporal Lobe Epilepsy. Neurology\| PubMed ID: 36750386	2023
Thalamostriatal disconnection underpins long-term seizure freedom in frontal lobe epilepsy surgery. Brain : a journal of neurology\| PubMed ID: 37062539	2023
Extent of piriform cortex resection in children with temporal lobe epilepsy. Annals of clinical and translational neurology\| PubMed ID: 37475156	2023
Refining computer-assisted SEEG planning with spatial priors - A novel comparison of implantation strategies across adult and paediatric centres. Neurophysiologie clinique = Clinical neurophysiology\| PubMed ID: 39808968	2025
Computer-assisted stereoelectroencephalography planning: center-specific priors enhance planning. Frontiers in neurology\| PubMed ID: 40083454	2025

Debayan Dasgupta

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