Epilepsy Surgery in the Last 10 Years: Advancements and Controversies

Abstract

The past decade has witnessed a transformative evolution in epilepsy surgery, marked by the introduction and maturation of the so-called “minimally invasive interventions,” neuromodulation strategies, and personalized surgical approaches. These developments have redefined treatment paradigms for drug-resistant epilepsy, offering safer, more targeted, and sometimes more effective alternatives to traditional open resections. The 2025 AES Surgery Symposium served as a platform for synthesizing the state-of-the-art in this dynamic field, highlighting not only the significant strides made in surgical and neurotechnological innovation but also the unresolved controversies that continue to shape clinical practice. This review aims to distill key themes from the symposium, including emerging surgical techniques, the resurgence of stereo-electroencephalography (SEEG)-guided thermocoagulation, the further integration of neuromodulation into mainstream epilepsy care, and the future of individualized surgical planning through advanced imaging and connectomics. While these innovations hold remarkable promise, their efficacy, accessibility, and long-term impact require rigorous scrutiny and global discourse.

Introduction

Over the last 10 years, epilepsy surgery has undergone a radical transformation fueled by interdisciplinary innovation and a paradigm shift toward precision medicine. The once-dominant landscape of open resections has expanded to include sophisticated surgical methods such as laser interstitial thermal therapy (LITT), stereo-electroencephalography (SEEG)-guided radiofrequency thermocoagulation (RF-TC), and endoscopic or robotic-assisted disconnections. Concurrently, neuromodulation therapies—including responsive neurostimulation (RNS) and deep brain stimulation (DBS)—have become cornerstones of treatment for patients who are not candidates for resection or ablative procedures.

These advances coincide with an intensified focus on the individualization of care. With the advent of high-resolution neuroimaging, functional connectomics, and real-time electrophysiology, surgical strategies are increasingly tailored to each patient's unique epileptogenic network. This progress has not come without challenges. The high cost of new technologies, variable efficacy across different patient populations, and the absence of standardized protocols have raised questions about equity, feasibility, and long-term outcomes. This review provides an in-depth examination of these innovations and the controversies they generate, framed by the discussions and presentations from the 2025 AES Surgery Symposium.

Less Invasive Approaches in Epilepsy Surgery

One of the most notable advancements in epilepsy surgery over the last decade has been the rise of less invasive techniques, which have been instrumental in reducing surgical morbidity and recovery times while maintaining efficacy. LITT has emerged as an alternative to traditional open resections, particularly for deep-seated epileptogenic foci and lesional temporal lobe epilepsy (TLE). LITT utilizes laser-generated heat to ablate epileptic tissue with minimal damage to surrounding structures. Studies have demonstrated that LITT offers shorter hospitalization periods and fewer complications compared to conventional surgeries.^1–13 However, concerns remain regarding the standardization of patient selection criteria, long-term seizure control rates, and the financial burden associated with this technology.

A significant controversy in epilepsy surgery over the last decade has been the debate between LITT and open resection. Proponents of LITT highlight its minimally invasive nature, lower risk of complications, and faster recovery times as major advantages. Studies have demonstrated favorable seizure control rates for LITT in select patient populations, particularly those with mesial temporal lobe epilepsy (MTLE).^6,12–14 However, concerns remain regarding the long-term durability of seizure control, as some patients experience recurrence, necessitating repeat procedures or eventual open surgery. ¹⁵

Efficacy of LITT Versus Open Resection

Despite its growing popularity, the long-term efficacy of LITT in achieving seizure control is still under scrutiny. Open resection, particularly ATL, continues to be considered the gold standard for the treatment of MTLE, with seizure freedom rates surpassing 60% to 70% in long-term follow-up studies.^16,17 ATL allows for the complete resection of the epileptogenic zone, offering a definitive solution for many patients with localized MTLE. This procedure's efficacy has been extensively documented across numerous clinical studies over several decades.

In contrast, LITT offers reduced recovery times and is often viewed as a viable option for patients who may not be suitable candidates for open resection due to comorbidities, anatomical challenges, or patient preferences. LITT involves targeted thermal ablation of the epileptogenic tissue, typically in the mesial temporal lobe, using MRI guidance. However, critics of LITT highlight that it does not always achieve the same level of seizure freedom as open resection, particularly in patients with larger or more complex epileptogenic zones. The inability to perform complete resection of all epileptogenic tissue, especially in patients with diffuse or multifocal seizure foci, may limit the long-term efficacy of LITT as compared to anterior temporal lobe surgery (ATL).^9,18

Several studies indicate that while LITT may provide significant short-term seizure control, it does not consistently match the long-term outcomes of open surgery. For example, a study by Jermakowicz et al ⁹ emphasized that incomplete ablation of the epileptogenic zone could contribute to recurrence of seizures in patients treated with LITT, especially those with extensive or multifocal epilepsy. Consequently, the role of LITT in the treatment of MTLE remains a subject of ongoing research, and further investigations are necessary to fully define its clinical utility.

Neuropsychological Outcomes and Potential Benefits of LITT

One of the key advantages of LITT over open surgery, particularly ATL, is its potential to minimize the cognitive and neuropsychological risks associated with epilepsy surgery. ATL, which involves the removal of brain tissue from the mesial temporal lobe, carries the risk of significant post-operative cognitive impairments, including memory deficits, particularly in verbal memory. These cognitive impairments can substantially impact patients’ quality of life and may be a deterrent for some individuals when considering surgical treatment for epilepsy.

LITT has been associated with a reduced risk of damage to critical brain structures that are involved in cognitive functions. By using smaller incisions and targeting specific areas of the epileptogenic zone with precision, LITT offers a surgical approach that may be less likely to interfere with functionally significant areas of the brain, such as those involved in memory and language. This reduced risk of cognitive decline is especially pertinent for patients who are concerned about preserving cognitive function, mainly in dominant temporal lobe, as it may offer an alternative with fewer long-term cognitive consequences compared to traditional open surgery.

Drane et al ³ examined the neuropsychological outcomes of epilepsy surgery, specifically comparing ATL and LITT. Their findings suggested that while patients who underwent ATL for MTLE often experienced significant memory deficits, particularly in the realm of verbal memory, those treated with LITT exhibited better preservation of cognitive functions. Specifically, patients treated with LITT demonstrated superior outcomes in domains such as memory and language, despite not always achieving complete seizure freedom. This cognitive preservation may be particularly important for patients who experience seizures that do not significantly interfere with their quality of life, but who are at risk for cognitive decline following more invasive procedures.

While the efficacy of LITT in seizure control may be somewhat lower than that of ATL, the preservation of cognitive function may provide a compelling trade-off for patients who prioritize neuropsychological outcomes over complete seizure freedom. The long-term benefits of cognitive preservation, particularly in patients with localized epilepsy foci, could enhance the attractiveness of LITT as a treatment option.

Financial Burden and Limitations in Low-Resource Settings

The financial burden of implementing LITT on a widespread scale remains one of the most significant barriers to its broader adoption, particularly in resource-limited settings. The technology required for LITT—including laser systems, MRI machines, and specialized neuronavigation equipment—is prohibitively expensive for many healthcare systems, especially in lower income countries. Furthermore, the ongoing costs associated with the maintenance and operation of these technologies add an additional financial strain on healthcare institutions.

In contrast, open resection surgeries, such as ATL, are generally less costly in terms of infrastructure and equipment. Although ATL requires more invasive surgery and extended recovery periods, it does not depend on the availability of advanced technologies, making it a more viable option for many hospitals and clinics in resource-limited areas. Given the financial challenges posed by LITT, its use is often restricted to high-income countries with the necessary infrastructure and funding.

The high cost of LITT, combined with the need for specialized training and expertise, underscores the importance of developing cost-effective strategies to integrate this technology into clinical practice in a way that can reach a broader patient population. Studies suggest that, while LITT can reduce hospital stays and recovery times, its high operational costs remain a key barrier to its widespread use in resource-constrained settings. ¹⁸

The Need for Multicenter, Randomized Controlled Trials

To definitively assess the role of LITT in the treatment of MTLE, particularly in comparison to traditional open resection, large-scale, multicenter randomized controlled trials (RCTs) are essential. Although initial studies suggest promising outcomes in terms of seizure control and cognitive preservation, the evidence base is still insufficient to establish clear guidelines for patient selection and long-term outcomes. Further RCTs are needed to evaluate the relative efficacy of LITT in achieving seizure freedom, particularly in patients with complex or multifocal epilepsy, and to determine whether its potential benefits in cognitive preservation outweigh its slightly lower success rates in seizure control.

The results of these trials will be critical in guiding clinical decision-making and in determining the most appropriate use of LITT in different patient populations. Additionally, future studies should assess the cost-effectiveness of LITT in various healthcare settings, including LMICs, to determine whether it can be implemented in a financially sustainable manner.

The Rediscovered Role of the Radiofrequency Thermocoagulation Method Guided by SEEG Electrodes

Radiofrequency (RF) thermocoagulation, first introduced in the 1950s, uses high-frequency alternating current delivered through a thin electrode to generate heat and coagulate tissue. This technique allows for targeted tissue destruction, which can disrupt the electrical circuits involved in epileptic activity, theoretically with reduced risks for cognitive and neurological deficits. However, the technique's potential was initially hampered by difficulties in accurately localizing epileptic foci, especially when they were located in deep or complex brain regions.^19–26

SEEG emerged as a powerful method to overcome these challenges. SEEG involves the implantation of depth electrodes to record brain activity directly, allowing for precise localization of epileptic foci, especially in patients with multifocal epilepsy or seizures originating from deeper brain structures. The combination of SEEG with RF thermocoagulation has allowed for more precise and individualized diagnostic interventions. Importantly, the method has been originally conceptualized as part of the SEEG method, as a diagnostic tool and not necessarily as a treatment option, although some groups have reported a small incidence of patients who obtained sustained seizure control after SEEG-guided RF procedures.^22–25

SEEG and Its Role in RF Thermocoagulation

SEEG provides highly detailed, real-time recordings of electrical activity in the brain, making it particularly valuable in the surgical management of epilepsy. The technique allows for the identification of the precise epileptic foci that may not be visible on traditional imaging modalities such as MRI or CT scans. SEEG can identify both cortical and subcortical foci, including those in regions that are difficult to access using other techniques.

The integration of RF thermocoagulation with SEEG allows for targeted destruction of epileptogenic tissue with minimal collateral damage. Using SEEG to guide RF thermocoagulation provides the advantage of real-time monitoring of brain activity during the procedure, ensuring that only the necessary tissue is destroyed while minimizing the risk of injuring functional brain areas. This approach has been particularly beneficial in patients with deep-seated or multifocal epileptic foci, as well as those with TLE, where precise localization is crucial.

Mechanism of RF Thermocoagulation

RF thermocoagulation delivers RF energy through an electrode, generating heat that causes coagulation and necrosis of targeted brain tissue. The extent of tissue destruction depends on several factors, including the duration of energy delivery, the power of the RF current, and the electrode's size and placement. The controlled destruction of the tissue is aimed at disrupting the abnormal electrical activity associated with seizures.

When used with SEEG, RF thermocoagulation benefits from precise localization of the epileptic foci, ensuring that only the areas responsible for seizure activity are ablated, while surrounding tissue remains unharmed. This approach has allowed for better clinical outcomes and reduced risks of neurological deficits, particularly when the epileptic focus is located near critical brain areas.

Clinical Outcomes and Efficacy

Numerous retrospective studies and prospective series have demonstrated that RF-TC, performed through SEEG electrodes, can achieve meaningful seizure reduction, and in some patients, long-term seizure freedom. Importantly, the results related to reduction of seizure frequency and severity tend to be ephemerous and not sustained, with return in the seizure patterns after couple weeks to 6 months. Guénot et al^24–29 reported seizure freedom in approximately 23% to 30% of carefully selected patients with mesial temporal or perisylvian epilepsy, with over 60% achieving a significant reduction in seizure frequency. Similar outcomes were corroborated by other authors, ²⁶ who found that SEEG-guided RF-TC could serve not only as a minimally invasive palliative measure but also as a functional diagnostic tool that helps predict surgical outcomes. Importantly, the technique offers a favorable safety profile, with low rates of hemorrhagic or infectious complications, making it particularly advantageous in pediatric and high-risk adult populations. While RF-TC is not a replacement for curative resective surgery in all cases, its efficacy in select focal epilepsy phenotypes supports its role as both a therapeutic and prognostic tool within the SEEG framework.

Future Directions

The future of RF thermocoagulation guided by SEEG in epilepsy treatment looks promising. Advances in imaging technologies, such as functional MRI and magnetoencephalography (MEG), may enhance the precision of target localization, further improving the effectiveness of the procedure. Additionally, combining RF thermocoagulation with other treatment modalities, such as DBS or transcranial magnetic stimulation (TMS), could offer enhanced therapeutic outcomes.

Furthermore, the integration of robotic assistance and advanced neuronavigation systems may improve the precision of electrode placement, reducing the risk of complications and optimizing treatment outcomes. Ongoing research into the optimization of RF thermocoagulation parameters and the development of more personalized treatment strategies will likely lead to even better outcomes for patients with drug-resistant epilepsy.

Hemispheric Surgery: Refining Techniques for Better Outcomes

For patients with hemispheric epilepsy, surgical intervention remains a crucial treatment option. Over the years, traditional hemispherectomy has evolved into more refined functional approaches that prioritize seizure control while minimizing morbidity. Functional hemispherectomy has gained favor due to its ability to preserve cortical structures while effectively disconnecting epileptogenic networks. Long-term studies have reinforced its role in improving seizure outcomes and quality of life, particularly in pediatric population.^30–49 Additionally, the emergence of techniques such as hemispherotomy and endoscopic-assisted disconnection have led to improved safety profiles while maintaining high seizure control rates.

Endoscopic techniques have also emerged as a less invasive alternative for hemispheric surgeries. With advancements in surgical visualization and instrumentation, endoscopic approaches offer reduced surgical trauma and faster recovery. Recent studies have demonstrated that endoscopic hemispherotomy is associated with reduced blood loss and shorter hospital stays compared to traditional open techniques. ⁵⁰ However, these methods present challenges, including technical limitations, the steep learning curve for surgeons, and the need for refined patient selection criteria. Comparative studies assessing the outcomes of endoscopic versus traditional approaches will be essential to determine the viability of these techniques in routine clinical practice.

In addition to endoscopic techniques, robotic-assisted approaches have gained attention for their potential to enhance precision in hemispheric epilepsy surgery. Robotic assistance enables more accurate trajectory planning and reduces intraoperative variability, potentially leading to better long-term outcomes. As these novel techniques continue to be refined, large-scale comparative studies will be crucial in establishing their role in epilepsy surgery.

Neuromodulation and Individualized Approaches

The field of neuromodulation in epilepsy has made significant strides in the past decade, with innovative technologies and individualized approaches improving the management of drug-resistant epilepsy. Two of the most notable advancements in this area are RNS and DBS, both of which have gained widespread acceptance and application in clinical practice. These techniques aim to modulate brain activity to prevent or reduce the frequency and severity of seizures, offering new hope for patients who have not responded to conventional therapies.

Responsive Neurostimulation

RNS, approved by the FDA in 2013, has become a valuable treatment option for patients with multifocal epilepsy who are not candidates for resective surgery. RNS works by detecting abnormal epileptiform activity in real-time and delivering targeted electrical pulses to disrupt this activity, preventing seizures from occurring. In the last decade, RNS technology has evolved significantly, with notable advancements in both hardware and software. One of the most important improvements is the ability to customize the stimulation parameters, including frequency, duration, and intensity, allowing for more personalized treatment regimens.^51,52 The introduction of individualized targeting strategies has played a critical role in improving the success rates of RNS for epilepsy, with precise mapping of thalamic-cortical networks becoming a key component of the treatment approach. ⁵¹

Recent studies^53–58 have provided new insights into the efficacy of RNS in specific patient populations. Nair and colleagues conducted a multicenter study evaluating the long-term effects of RNS in patients with epilepsy originating from multiple brain regions. The study demonstrated that RNS could significantly reduce seizure frequency (by ∼50%) and improve overall quality of life in these patients, with a subset experiencing near-complete seizure freedom. ⁵⁹ These results have been pivotal in reinforcing the potential of RNS for patients with multifocal epilepsy, whose seizures are otherwise difficult to control using traditional treatments. However, the study also highlighted the need for ongoing optimization of stimulation parameters and further research into identifying predictors of RNS response.

Advances in imaging and connectomics have further optimized the use of RNS. The integration of high-resolution brain imaging, such as functional magnetic resonance imaging (fMRI) and diffusion tensor imaging (DTI) has enabled more accurate identification of seizure foci and more precise placement of the RNS electrode. Additionally, the growing field of brain network connectivity and connectomics has allowed for the exploration of epileptic brain networks, which has been instrumental in refining target selection and improving the precision of neuromodulatory interventions. ⁶⁰

Recent findings from the Nautilus trials, focused on centromedian thalamic RNS for epilepsy, show promising results in patients with generalized or multifocal drug-resistant epilepsy. The Nautilus trial, a multicenter randomized controlled study, reported a significant reduction in seizure frequency (by more than 40%) after DBS targeting the centromedian nucleus, particularly in patients with generalized seizures that were poorly controlled by medications. Notably, patients also reported improvements in alertness, mood, and cognitive function, suggesting that the therapeutic effects of centromedian thalamic DBS extend beyond seizure control and may improve overall brain function. These findings support the idea that targeting thalamic circuits involved in brain network synchronization could have broader therapeutic benefits for epilepsy.

The Role of Individualized Targeting in Neuromodulation

The growing emphasis on individualized targeting has been instrumental in advancing the field of neuromodulation for epilepsy. Recent efforts to integrate personalized approaches, including the use of patient-specific anatomical, electrophysiological, and genetic profiles, have led to more tailored and effective treatments. For instance, individualized stimulation parameters based on the patient's unique brain network dynamics have been shown to enhance the efficacy of both RNS and DBS.^51,52

Conclusions and Future Directions

Epilepsy surgery is undergoing a transformative shift, with innovative techniques and neuromodulation approaches expanding treatment options for patients with drug-resistant epilepsy. Invasive procedures associated with less complications such as LITT, stereotactic thermocoagulation, and intracranial neuromodulation have demonstrated significant potential, though ongoing research is necessary to address concerns regarding long-term efficacy and accessibility.