Initial experience with magnetic resonance-guided focused ultrasound stereotactic surgery for central brain lesions in young adults

Advancements in Surgical Therapies for Drug-Resistant Epilepsy: A Paradigm Shift towards Precision Care

Epilepsy, a prevalent neurological disorder characterized by recurrent seizures, affects millions worldwide, with a significant proportion resistant to pharmacological treatments. Surgical interventions have emerged as pivotal in managing drug-resistant epilepsy (DRE), aiming to reduce seizure frequency or achieve seizure freedom. Traditional resective surgeries have evolved with technological advances, enhancing precision and safety. Neurostimulation techniques, such as responsive neurostimulation (RNS) and deep brain stimulation (DBS), now provide personalized, real-time seizure management, offering alternatives to traditional surgery. Minimally invasive ablative methods, such as laser interstitial thermal therapy (LITT) and Magnetic Resonance-guided Focused Ultrasound (MRgFUS), allow for targeted destruction of epileptogenic tissue with reduced risks and faster recovery times. The use of stereo-electroencephalography (SEEG) and robotic assistance has further refined surgical precision, enhancing outcomes. These advancements mark a paradigm shift towards precision medicine in epilepsy care, promising improved seizure management and quality of life for patients globally. This review outlines the latest innovations in epilepsy surgery, emphasizing their mechanisms and clinical implications to improve outcomes for patients with DRE.

MRgFUS disconnection surgery for hypothalamic hamartoma-related epilepsy: case report and literature review

BACKGROUND

Drug-resistant epilepsy (DRE) secondary to hypothalamic hamartoma (HH) often requires surgical resection or stereotactic radiosurgery, which frequently fail to provide satisfactory outcomes and are associated with severe side effects. Magnetic resonance-guided focused ultrasound (MRgFUS) may represent a minimally invasive surgical approach to HH by offering precise thermal ablation of sub-millimetric brain targets while sparing surrounding structures.

METHODS

We present the case of a 19-year-old man with HH-associated DRE, who was successfully treated with MRgFUS. The procedure resulted in effective ablation of the hypothalamic interface of the HH, disconnecting the epileptogenic lesion from the surrounding brain tissue. We also reviewed the literature on MRgFUS for DRE.

RESULTS

The patient experienced a complete resolution of seizures and significant improvements in social and occupational functioning over an 18-month follow-up period. No neurological, cognitive, or endocrinological adverse effects were observed.

CONCLUSION

Our case report and literature review suggest that MRgFUS may achieve adequate seizure control in DRE associated with HH without adverse effects. While MRgFUS shows promise for other forms of DRE, data remain preliminary, and some safety concerns persist. Further studies with long-term follow-up are warranted to better support the use of MRgFUS in DRE.

Clinical Trials of Focused Ultrasound for Brain Tumors

BACKGROUND

It is unclear as to where we stand with respect to utilizing emerging focused ultrasound (FUS) technology in the setting of brain tumor treatment in pediatric patients, such as malignant diffuse intrinsic pontine glioma, and various adult counterparts. Correspondingly, the aim of this study was to present a contemporary summary of all pertinent clinical trials to date.

METHODS

The ClinicalTrials.gov database was reviewed in January 2025 for all possible clinical trials involving FUS in the management of brain tumors. These were then screened against selection criteria to identify pertinent clinical trials.

RESULTS

A total of 30 clinical trials were identified. The majority were focused on adult patients (24/30, 80%), with the most common tumor type being glioblastoma (GBM) (14/30, 47%). There were also trials focused on pediatric patients only (5/30, 17%), as well as diffuse intrinsic pontine glioma (DIPG) (5/30, 17%). The most prevalent primary outcome of interest was safety (26/30, 87%). The majority of trials were active, either recruiting currently (12/30, 40%), or active but not recruiting currently (3/30, 10%). North America (22/30, 73%) was the most common location for the primary coordinating institution, and the median number of institutions per trial was one. The median expected start year for all trials was 2021, and the completion year was 2024. To date, there have been no results (interim or final) formally reported, although preliminary reports in the literature indicate this to be a safe procedure. Anecdotal trends suggest later trials target the blood-brain barrier more, involve more pediatric patients, and are more based in the United States.

CONCLUSION

There exists a number of early-stage clinical trials investigating FUS to treat a variety of brain tumors in pediatric patients, as well as adult patients, with a significant clinical potential to improve outcomes. To date, no official results have been published, however anecdotal evidence is promising, and a number of results are expected soon.

Focused ultrasound for treatment of epilepsy: a systematic review and meta-analysis of preclinical and clinical studies

Various preclinical and clinical studies have demonstrated the neuromodulatory and ablative effects of focused ultrasound (FUS). However, the safety and efficacy of FUS in clinical settings for treating epilepsy have not been well established. This study aims to provide a systematic review of all preclinical and clinical studies that have used FUS for the treatment of epilepsy. A systematic search was conducted using Scopus, Web of Science, PubMed, and Embase databases. All preclinical and clinical studies reporting outcomes of FUS in the treatment of epilepsy were included in the systematic review. Random-effect meta-analysis was performed to determine safety in clinical studies and seizure activity reduction in preclinical studies. A total of 24 articles were included in the study. Meta-analysis demonstrated that adverse events occurred in 13% (95% CI = 2-57%) of patients with epilepsy who underwent FUS. The frequency of adverse events was higher with the use of FUS for lesioning (36%, 95% CI = 4-88%) in comparison to neuromodulation (5%, 95% CI = 0-71%), although this difference was not significant (P = 0.31). Three-level meta-analysis in preclinical studies demonstrated a reduced spike rate in neuromodulating FUS compared to the control group (P = 0.02). According to this systematic review and meta-analysis, FUS can be considered a safe and feasible approach for treating epileptic seizures, especially in drug-resistant patients. While the efficacy of FUS has been demonstrated in several preclinical studies, further research is necessary to confirm its effectiveness in clinical practice and to determine the adverse events.

A Scoping Review of Focused Ultrasound Enhanced Drug Delivery for Across the Blood-Brain Barrier for Brain Tumors

BACKGROUND AND OBJECTIVES

Previous mechanisms of opening the blood-brain barrier (BBB) created a hypertonic environment. Focused ultrasound (FUS) has recently been introduced as a means of controlled BBB opening. Here, we performed a scoping review to assess the advances in drug delivery across the BBB for treatment of brain tumors to identify advances and literature gaps.

METHODS

A review of current literature was conducted through a MEDLINE search inclusive of articles on FUS, BBB, and brain tumor barrier, including human, modeling, and animal studies written in English. Using the Rayyan platform, 2 reviewers (J.P and C.Y) identified 967 publications. 224 were chosen to review after a title screen. Ultimately 98 were reviewed. The scoping review was designed to address the following questions: (1) What FUS technology improvements have been made to augment drug delivery for brain tumors? (2) What drug delivery improvements have occurred to ensure better uptake in the target tissue for brain tumors?

RESULTS

Microbubbles (MB) with FUS are used for BBB opening (BBBO) through cavitation to increase its permeability. Drug delivery into the central nervous system can be combined with MB to enhance transport of therapeutic agents to target brain tissue resulting in suppression of tumor growth and prolonging survival rate, as well as reducing systemic toxicity and degradation rate. There is accumulating evidence demonstrating that drug delivery through BBBO with FUS-MB improves drug concentrations and provides a better impact on tumor growth and survival rates, compared with drug-only treatments.

CONCLUSION

Here, we review the role of FUS in BBBO. Identified gaps in the literature include impact of tumor microenvironment and extracellular space, improved understanding and control of MB and drug delivery, further work on ideal pharmacologics for delivery, and clinical use.

Magnetic Resonance-Guided Focused Ultrasound Thalamotomy for Essential Tremor in Fahr's Disease: Case Report

INTRODUCTION

Magnetic resonance-guided focused ultrasound (MRgFUS) thalamotomy effectively treats medication-resistant essential tremor (ET). Usually, intracranial calcifications are excluded as no-pass zones because of their low penetrability which may limit the effectiveness of treatment and lead to unintended side effects. This case report illustrates the efficacy of unilateral MRgFUS for tremor control in a patient with extensive basal ganglia calcifications due to Fahr's disease.

CASE PRESENTATION

A 69-year-old right-handed male with debilitating Fahn-Tolosa-Marin grade 3-4 bilateral hand tremor underwent unilateral left MRgFUS thalamotomy. The treatment involved careful preoperative planning to accommodate his extensive basal ganglia calcifications, element path consideration, and skull density ratio to ensure accurate and effective lesioning. Posttreatment, the patient exhibited complete abolition of tremor on the treated side with minor transient dysarthria and imbalance. Follow-up at 12 weeks posttreatment showed sustained tremor relief and an absence of any adverse effects, validating the procedural adjustments made to accommodate the unique challenges posed by his intracranial calcifications.

CONCLUSION

MRgFUS can be safely and effectively applied in certain patients with extensive basal ganglia calcifications - in this case, due to Fahr's disease. This case report suggests expanding the application of MRgFUS to patients with extensive intracranial calcifications who previously might not have been considered suitable candidates for MRgFUS.

The role of focused ultrasound for pediatric brain tumors: current insights and future implications on treatment strategies

INTRODUCTION

Focused ultrasound (FUS) is an innovative and emerging technology for the treatment of adult and pediatric brain tumors and illustrates the intersection of various specialized fields, including neurosurgery, neuro-oncology, radiation oncology, and biomedical engineering.

OBJECTIVE

The authors provide a comprehensive overview of the application and implications of FUS in treating pediatric brain tumors, with a special focus on pediatric low-grade gliomas (pLGGs) and the evolving landscape of this technology and its clinical utility.

METHODS

The fundamental principles of FUS include its ability to induce thermal ablation or enhance drug delivery through transient blood-brain barrier (BBB) disruption, emphasizing the adaptability of high-intensity focused ultrasound (HIFU) and low-intensity focused ultrasound (LIFU) applications.

RESULTS

Several ongoing clinical trials explore the potential of FUS in offering alternative therapeutic strategies for pathologies where conventional treatments fall short, specifically centrally-located benign CNS tumors and diffuse intrinsic pontine glioma (DIPG). A case illustration involving the use of HIFU for pilocytic astrocytoma is presented.

CONCLUSION

Discussions regarding future applications of FUS for the treatment of gliomas include improved drug delivery, immunomodulation, radiosensitization, and other technological advancements.

Strategies to Improve Drug Delivery Across the Blood-Brain Barrier for Glioblastoma

PURPOSE OF REVIEW

Glioblastoma remains resistant to most conventional treatments. Despite scientific advances in the past three decades, there has been a dearth of effective new treatments. New approaches to drug delivery and clinical trial design are needed.

RECENT FINDINGS

We discuss how the blood-brain barrier and tumor microenvironment pose challenges for development of effective therapies for glioblastoma. Next, we discuss treatments in development that aim to overcome these barriers, including novel drug designs such as nanoparticles and antibody-drug conjugates, novel methods of drug delivery, including convection-enhanced and intra-arterial delivery, and novel methods to enhance drug penetration, such as blood-brain barrier disruption by focused ultrasound and laser interstitial thermal therapy. Lastly, we address future opportunities, positing combination therapy as the best strategy for effective treatment, neoadjuvant and window-of-opportunity approaches to simultaneously enhance therapeutic effectiveness with interrogation of on-treatment biologic endpoints, and adaptive platform and basket trials as imperative for future trial design. New approaches to GBM treatment should account for the blood-brain barrier and immunosuppression by improving drug delivery, combining treatments, and integrating novel clinical trial designs.

Current state of the art of traditional and minimal invasive epilepsy surgery approaches

Introduction

Open resective surgery remains the main treatment modality for refractory epilepsy, but is often considered a last resort option due to its invasiveness.

Research question

This manuscript aims to provide an overview on traditional as well as minimally invasive surgical approaches in modern state of the art epilepsy surgery.

Materials and methods

This narrative review addresses both historical and contemporary as well as minimal invasive surgical approaches in epilepsy surgery. Peer-reviewed published articles were retrieved from PubMed and Scopus. Only articles written in English were considered for this work. A range of traditional and minimally invasive surgical approaches in epilepsy surgery were examined, and their respective advantages and disadvantages have been summarized.

Results

The following approaches and techniques are discussed: minimally invasive diagnostics in epilepsy surgery, anterior temporal lobectomy, functional temporal lobectomy, selective amygdalohippocampectomy through a transsylvian, transcortical, or subtemporal approach, insulo-opercular corticectomies compared to laser interstitial thermal therapy, radiofrequency thermocoagulation, stereotactic radiosurgery, neuromodulation, high intensity focused ultrasound, and disconnection surgery including callosotomy, hemispherotomy, and subpial transections.

Discussion and conclusion

Understanding the benefits and disadvantages of different surgical approaches and strategies in traditional and minimal invasive epilepsy surgery might improve the surgical decision tree, as not all procedures are appropriate for all patients.

[Hypothalamic hamartoma dissection using focused ultrasound under MRI control. The first successful experience in Russia]

Treatment of motor disorders by MRI-guided focused ultrasound is an alternative to neuro- and radiosurgery such as stereotactic radiofrequency ablation and thalamotomy with a gamma knife. However, safety, efficacy and feasibility of this technology for intracranial neoplasms are still unclear. The authors report successful hypothalamic hamartoma dissection by MRI-guided focused ultrasound in a 32-year-old woman with drug-resistant gelastic epilepsy and violent laughter and crying attacks. Magnetic resonance imaging revealed type II hypothalamic hamartoma. The last one was detached from surrounding brain tissue by MRI-guided focused ultrasound without side effects. Symptoms regressed immediately after surgery. No laughter and crying attacks were observed throughout 6-month follow-up.

Multimodal Approach for the Treatment of Complex Hypothalamic Hamartomas

Hypothalamic hamartomas (HHs) are rare congenital lesions formed by heterotopic neuronal and glial cells attached to the mammillary bodies, tuber cinereum, and hypothalamus.They often present with an intractable epilepsy typically characterized by gelastic seizures but commonly associated with other types of refractory seizures. The clinical course is progressive in most of the cases, starting with gelastic seizures in infancy and deteriorating into complex seizure disorders that result in catastrophic epilepsy associated with cognitive decline and behavioral disturbances.Hamartomas are known to be intrinsically epileptogenic and the site of origin for the gelastic seizures. As antiepileptic drugs are typically ineffective in controlling HH-related epilepsy, different surgical options have been proposed as a treatment to achieve seizure control. Resection or complete disconnection of the hamartoma from the mammillothalamic tract has proved to achieve a long-lasting control of the epileptic syndrome.Usually, symptoms and their severity are typically related to the size, localization, and type of attachment. Precocious puberty appears mostly in the pedunculated type, while epileptic syndrome and behavioral decline are frequently related to the sessile type. For this reason, different classifications of HHs have been developed based on their size, extension, and type of attachment to the hypothalamus.The bigger and more complex hypothalamic hamartomas typically present with severe refractory epilepsy, behavioral disturbances, and progressive cognitive decline posing a formidable challenge for the control of these symptoms.We present here our experience with the multimodal treatment for complex hypothalamic hamartomas. After an in-depth review of the literature, we systematize our approach for the different types of hypothalamic hamartomas.

The evolution of pediatric neurosurgery: reflection of personal experience of the last half-century

OBJECTIVES

In the past 50 years, pediatric neurosurgery has made tremendous strides, and gained its own identity as a distinct subspecialty. I have personally observed this progress and evolution in pediatric neurosurgery in multiple dimensions, which are described based upon my own experience and reflection.

METHODS

The development and evolutions of multiple domains of pediatric neurosurgery, including neuroimaging, hydrocephalus, pediatric brain tumor, spinal dysraphism, craniosynostosis, vascular malformation, functional neurosurgery and spinal disorders were reviewed and commented on based upon my own experience and reflection.

RESULTS

The field of pediatric neurosurgery has grown in all aspects of diagnosis and therapy owing to the introduction of computers, innovative techniques and technologies and new discoveries of scientific data including molecular investigations.

CONCLUSION

A minimally invasive approach and molecular target therapy are a current trend. The past half century's clinical experience and advances in biomedical knowledge and techniques provide foundation for further improvement in the care of children of the next generation. Prospective artificial intelligence will likely promote further advances in pediatric neurosurgery.

Characteristics of Pain During MRI-Guided Focused Ultrasound Thalamotomy

BACKGROUND

Magnetic resonance imaging-guided focused ultrasound (MRgFUS) has become popular as an incisionless mode of neurosurgical treatment. However, head pain during sonication is common and its pathophysiology remains poorly understood.

OBJECTIVE

To explore the characteristics of head pain occurring during MRgFUS thalamotomy.

METHODS

Our study comprised 59 patients who answered questions about the pain they experienced during unilateral MRgFUS thalamotomy. The location and features of pain were investigated using a questionnaire including the numerical rating scale (NRS) to estimate maximum pain intensity and the Japanese version of the Short Form of McGill Pain Questionnaire 2 to evaluate the quantitative and qualitative dimensions of pain. Several clinical factors were investigated for possible correlation with pain intensity.

RESULTS

Forty-eight patients (81%) reported sonication-related head pain, and the degree of pain was severe (NRS score ≥ 7) in 39 patients (66%). The distribution of sonication-related pain was "localized" in 29 (49%) and "diffuse" in 16 (27%); the most frequent location was the "occipital" region. The pain features most frequently reported were those in the "affective" subscale of the Short Form of McGill Pain Questionnaire 2. Patients with diffuse pain had a higher NRS score and lower skull density ratio than did patients with localized pain. The NRS score negatively correlated with tremor improvement at 6 months post-treatment.

CONCLUSION

Most patients in our cohort experienced pain during MRgFUS. The distribution and intensity of pain varied according to the skull density ratio, indicating that the pain might have had different origins. Our results may contribute to the improvement of pain management during MRgFUS.