Disabling amnestic syndrome following stereotactic laser ablation of a hypothalamic hamartoma in a patient with a prior temporal lobectomy

Direct resection is a safe and effective strategy to control seizures in patients with hypothalamic hamartoma

Achieving favorable seizure outcomes is challenging in patients with seizures resulting from hypothalamic hamartoma. Although minimally invasive and non-invasive surgical procedures are used to treat this population, these procedures have limitations. Therefore, we analyzed the outcomes of patients with hypothalamic hamartoma following direct resection. We included 159 patients with hypothalamic hamartoma who underwent direct resection using the transcallosal interforniceal approach between 2011 and 2018. The relationships between clinical parameters and seizure outcomes were analyzed. In total, 55.3% achieved gross total resection and 25.2% underwent near-total resection. Of all patients, 79.2% were overall seizure-free at one year, but this number dropped to 77.0% at more than five years. Moreover, 88.4% (129/146) reached gelastic seizure (GS)-free status at one year and this number increased to 89.0% (97/109) at more than five years. Seventy-one patients took antiseizure medication (ASM) long-term, 68 took it for one year, and 11 took it for one-half year. The duration of ASM consumption (p < 0.001) and extent of hypothalamic hamartoma resection (p = 0.016) were significant independent predictors of long-term overall seizure-free survival, while the duration of ASM consumption (p = 0.011) and extent of hypothalamic hamartoma resection (p = 0.026) were significant independent predictors of long-term GS-free survival. Most patients' behavior, school performance, and intelligence were not affected after surgery. Direct resection is effective and safe strategy for patients with hypothalamic hamartomas. Hypothalamic hamartomas should be removed as completely as possible, and patients should take ASM long-term following surgery to reach long-term overall seizure-free or GS-free status.

Clinical Presentation and Management of Hypothalamic Hamartomas: A Systematic Review of the Literature

Hypothalamic hamartomas (HHs) are composed of abnormally distributed but cytologically normal cellular elements. This disease typically manifests in infancy with gelastic seizures characterized by outbursts of mechanical laughter (mirthless laughter), altered or retained consciousness, refractory to antiepileptic, and later progresses to behavioral and cognitive disturbances and secondary seizure types. A systematic review of the literature on the clinical presentation and management of HHs. A literature search was carried out in electronic databases such as PubMed, COCHRANE, SCOPUS, ScienceDirect, which included the studies reported on “hypothalamic,” “hamartoma,” and “epilepsy,” as well as the outcome with full texts in English. Letters, case reports, reviews, preclinical studies, conference proceedings, protocols, and nonhuman studies were excluded. Duplicates were removed in EndNote X7, and titles and abstracts of all listed articles were scanned. Data analysis of all included studies indicates that smaller lesions result in better outcomes and stereotactic laser ablative procedures have the highest Engel class I outcome percentage. Delalande type II lesions are much more common (n=201) followed by type III (n = 182), IV (n = 71), and I (n = 50). Stereotactic laser ablation is safe for large lesions. HHs can be treated safely when they are small. Therefore, early identification and intervention play a major role. This also prevents the seizure progression, leading to morbidity. SLA has fewer complications and increased seizure-free survival compared to other modalities of treatment.

Microsurgical management of complex hypothalamic hamartomas in the era of minimally invasive therapy: a case series and narrative review

INTRODUCTION

There has been a paradigm shift in the management of hypothalamic hamartoma (HH) from traditional microsurgical techniques to less invasive alternatives. However, large and extensive HH may fail to respond to these therapies, ultimately necessitating craniotomies.

METHODS

All patients who underwent microsurgical resection of a complex HH by the 2 senior authors from 2011-2021 were included. Charts were retrospectively reviewed and demographic, clinical, imaging, and outcome data were recorded.

RESULTS

8 patients (mean age 7 years) were included. 2 had failed previous treatments. All 7 presented with gelastic seizures and cognitive dysfunction, 6 exhibited central precocious puberty, and 3 had behavioral problems. Mean lesion size was 21.6 mm and all had interpeduncular extension, 5 had intraventricular extension (Delalande type I: 3, type III: 4, type IV: 1). A frontotemporal orbitozygomatic (FTOZ) approach with optic nerve decompression was used in all patients, supplemented by another approach in 3 (endoscopic transventricular: 3, transcallosal: 1). Gross total resection was achieved in 6 patients and subtotal resection in 2. Transient complications occurred in 3 patients (37.5%): self-limited sodium imbalance (n=3), subdural hygroma (n=2). Permanent complications occurred in 2 patients (25%): perforator infarct (n=1), short-term memory loss (n=1). All patients experienced seizure resolution with preserved hypothalamic-pituitary axis function. After a mean follow-up of 41 months (2-66), 7 patients remain seizure-free, while 1 has rare seizures. Cognitive and behavioral symptoms improved in all patients.

CONCLUSION

For large HH with interpeduncular extension, microsurgery via the FTOZ approach is a safe and highly effective treatment modality.

[Surgical treatment of epilepsy in patients with hypothalamic hamartomas]

The purpose of this review was to analyze the current ideas about various techniques and methods for treating epilepsy in patients with hypothalamic hamartomas including microsurgery, endoscopy, radiofrequency thermal destruction, stereotactic laser ablation and radiosurgery. Data characterizing their effectiveness, limitations and complications are considered.

CONCLUSION

When choosing the optimal treatment option, it is necessary to take into account patient age and course of disease, anatomical and topographic features of hamartoma location, previous attempts of treatment, opinion of the patient and his guardians, as well as surgical experience.

Magnetic Resonance-Guided Laser Interstitial Thermal Therapy (MR-gLiTT) in Pediatric Epilepsy Surgery: State of the Art and Presentation of Giannina Gaslini Children's Hospital (Genoa, Italy) Series

Magnetic resonance-guided laser interstitial thermal therapy (MR-gLiTT) is a novel minimally invasive treatment approach for drug-resistant focal epilepsy and brain tumors. Using thermal ablation induced by a laser diode implanted intracranially in a stereotactic manner, the technique is highly effective and safe, reducing the risk associated with more traditional open surgical approaches that could lead to increased neurological morbidity. Indications for MR-gLiTT in pediatric epilepsy surgery include hypothalamic hamartoma, tuberous sclerosis complex, cavernoma-related epilepsy, SEEG-guided seizure onset zone ablation, corpus callosotomy, periventricular nodular heterotopia, mesial temporal lobe epilepsy, and insular epilepsy. We review the available literature on the topic and present our series of patients with drug-resistant epilepsy treated by MR-gLiTT. Our experience, represented by six cases of hypothalamic hamartomas, one case of tuberous sclerosis, and one case of dysembryoplastic neuroepithelial tumor, helps to confirm that MR-gLiTT is a highly safe and effective procedure for several epilepsy conditions in children.

Long-term cognitive outcome after radiosurgery in epileptic hypothalamic hamartomas and review of the literature

OBJECTIVE

Epileptic patients with hypothalamic hamartoma (HH) frequently present cognitive impairments. Surgical techniques aiming at HH can be very efficient for epilepsy relief and cognitive improvement but are also demonstrated to carry a significant risk of additional reduction in memory function in these already disabled patients. Gamma knife radiosurgery (GKS) offers an efficient minimally invasive procedure. We evaluated the effect of stereotactic radiosurgery on cognitive outcome.

METHODS

We designed a prospective single-center case series study. Thirty-nine epileptic patients (median age = 17 years, range = 4-50) with HH underwent preoperative and postoperative testing of intelligence quotient (IQ; all patients), including a working memory component, and other memory function testing (for patients ≥16 years old). All patients were prospectively evaluated and underwent complete presurgical and postsurgical clinical, electrophysiological, endocrinal, and visual assessments. In all patients, the postoperative assessment was performed at least 3 years after radiosurgery. We explored what variables correlate with cognitive outcome. Literature review was done for other surgical techniques and their risks for cognitive complications after surgery.

RESULTS

No decline was observed in intellectual ability (including working memory) after GKS, and no memory decline was seen in adults. We observed significant improvement (>1 SD in z-score) in working memory index (46%) and processing speed index (35%), as well as improvement in full-scale IQ (24%), verbal comprehension index (11%), perceptual organization index (21%), verbal learning (20%), and visual learning (33%). Before GKS, the probability of seizure cessation was higher in patients with higher cognitive performance. After GKS, the cognitive improvement was significantly higher in the seizure-free patients compared to the non-seizure-free patients.

SIGNIFICANCE

We found clear cognitive improvement in a high percentage of patients but importantly no significant decline in intellectual ability (including working memory) and no decline in memory in adult patients 3 years after GKS. GKS compares favorably to the other surgical techniques in terms of cognitive outcome, with similar seizure freedom.

Epileptic Spasms in a Large Hypothalamic Hamartoma Cohort

INTRODUCTION

Hypothalamic hamartoma is rarely associated with epileptic spasms. We describe epileptic spasms in a large cohort of hypothalamic hamartoma patients.

METHODS

We performed a retrospective chart review between March 2011 and March 2020 to identify patients with hypothalamic hamartoma and epilepsy.

RESULTS

We identified 114 patients with hypothalamic hamartoma and epilepsy, only 3 male patients (2.6%) also had epileptic spasms. The epileptic spasms developed between 6 and 18 months of age. Epileptic spasms resolved with oral prednisolone in 1 and with vigabatrin in the second patient. The third patient continued epileptic spasms despite multiple antiepileptic drugs and partial resection of hypothalamic hamartoma. All 3 patients underwent laser-ablation of hypothalamic hamartoma at the age of 14, 29, and 63 months. The seizure burden decreased by 100%, 84%, and 93% at follow-up (3-47 months).

CONCLUSIONS

Epileptic spasms are rare in hypothalamic hamartoma patients and early laser-ablation could potentially treat epileptic spasms and all other seizure types associated with hypothalamic hamartoma.

Stereotactic radiofrequency thermocoagulation and resective surgery for patients with hypothalamic hamartoma

OBJECTIVE

In this study, the authors compared the efficacy and safety of stereotactic radiofrequency thermocoagulation (SRT) and resective surgery (RS) for patients with hypothalamic hamartoma (HH).

METHODS

The authors included all patients with HHs who were treated by SRT or hamartoma resection. Seizure outcomes were assessed by blinded observers according to the International League Against Epilepsy (ILAE) classification. Favorable seizure outcomes were defined as ILAE classes 1 and 2, and unfavorable seizure outcomes were defined as ILAE classes 3-6.

RESULTS

Twenty-nine patients who underwent SRT or RS met the inclusion criteria; 3 were excluded because they had completed less than 12 months of follow-up. Most of the patients (20 of 26; 76.9%) had small HHs (i.e., maximum HH diameter less than 20 mm). The patients' follow-up time ranged from 12 to 66 months (median 60 months). At the last follow-up, favorable outcomes were observed in 9 patients (69.2%) who had undergone SRT and 10 patients (76.9%) who had undergone HH resection. No significant difference was found in seizure outcomes between SRT and RS recipients. Patients with giant HHs were more likely than patients with smaller tumors to undergo multiple resections (p = 0.043, univariate logistic regression; significant). However, no significant difference was found between SRT and RS recipients in terms of the number of procedures per patient. SRT recipients had fewer and less-severe adverse events than RS recipients.

CONCLUSIONS

For patients with small HHs, SRT provides similar seizure outcomes to RS with a less invasive procedure. Patients who underwent SRT experienced fewer and lighter adverse effects than patients who had RS. Patients with giant HHs were more likely to undergo multiple HH resections.

Magnetic Resonance Imaging-Guided Laser Interstitial Thermal Therapy for Epilepsy: Systematic Review of Technique, Indications, and Outcomes

BACKGROUND

For patients with focal drug-resistant epilepsy (DRE), surgical resection of the epileptogenic zone (EZ) may offer seizure freedom and benefits for quality of life. Yet, concerns remain regarding invasiveness, morbidity, and neurocognitive side effects. Magnetic resonance-guided laser interstitial thermal therapy (MRgLITT) has emerged as a less invasive option for stereotactic ablation rather than resection of the EZ.

OBJECTIVE

To provide an introduction to MRgLITT for epilepsy, including historical development, surgical technique, and role in therapy.

METHODS

The development of MRgLITT is briefly recounted. A systematic review identified reported techniques and indication-specific outcomes of MRgLITT for DRE in human studies regardless of sample size or follow-up duration. Potential advantages and disadvantages compared to available alternatives for each indication are assessed in an unstructured review.

RESULTS

Techniques and outcomes are reported for mesial temporal lobe epilepsy, hypothalamic hamartoma, focal cortical dysplasia, nonlesional epilepsy, tuberous sclerosis, periventricular nodular heterotopia, cerebral cavernous malformations, poststroke epilepsy, temporal encephalocele, and corpus callosotomy.

CONCLUSION

MRgLITT offers access to foci virtually anywhere in the brain with minimal disruption of the overlying cortex and white matter, promising fewer neurological side effects and less surgical morbidity and pain. Compared to other ablative techniques, MRgLITT offers immediate, discrete lesions with real-time monitoring of temperature beyond the fiber tip for damage estimates and off-target injury prevention. Applications of MRgLITT for epilepsy are growing rapidly and, although more evidence of safety and efficacy is needed, there are potential advantages for some patients.

Hypothalamic Hamartomas: A Comprehensive Review of Literature - Part 3: Updates on Radiotherapy Management

Hypothalamic hamartomas (HH) are rare, non-neoplastic heterotopic tissues which contains normal neurons and glia including oligodendrocytes and fibrillary astrocytes but in an abnormal distribution. They arise from the floor of the third ventricle, tuber cinereum, or mammillary bodies. Estimated incidence ranges from 1 in 50,000 to 1 in 1,000,000. Hypothalamic hamartomas are associated with different clinical presentations including various types of seizures, most characteristically; the gelastic seizures, precocious puberty, cognitive impairment and behavioral changes. In this review, the authors discuss the recent advancements in different modalities of radiotherapy and their application in hypothalamic hamartomas management.

MRI-Guided Laser Interstitial Thermal Therapy for Epilepsy

MRI-guided laser interstitial thermal therapy for epilepsy (LITT-E) has become an established, minimally invasive alternative to traditional epilepsy surgery. LITT-E is particularly valuable in cases in which open surgery poses unacceptably high morbidity or patient preference precludes craniotomy. Here we present a focused review of technical details and application of LITT to both focal and generalized epilepsy.

Curative and palliative MRI-guided laser ablation for drug-resistant epilepsy

Epilepsy is a common neurological disorder occurring in 3% of the US adult population. It is characterised by seizures resulting from aberrant hypersynchronous neural activity. Approximately one-third of newly diagnosed epilepsy cases fail to become seizure-free in response to antiseizure drugs. Optimal seizure control, in cases of drug-resistant epilepsy, often requires neurosurgical intervention targeting seizure foci, such as the temporal lobe. Advances in minimally invasive ablative surgical approaches have led to the development of MRI-guided laser interstitial thermal therapy (LITT). For refractory epilepsy, this surgical intervention offers many advantages over traditional approaches, including real-time lesion monitoring, reduced morbidity, and in some reports increased preservation of cognitive and language processes. We review the use of LITT for epileptic indications in the context of its application as a curative (seizure freedom) or palliative (seizure reduction) measure for both lesional and non-lesional forms of epilepsy. Furthermore, we address the use of LITT for a variety of extratemporal lobe epilepsies. Finally, we describe clinical outcomes, limitations and future applications of LITT for epilepsy.

A novel use of the NeuroBlate SideFire probe for minimally invasive disconnection of a hypothalamic hamartoma in a child with gelastic seizures

The authors describe the case of a 22-month-old boy who presented with gelastic seizures and developmental delay. Magnetic resonance imaging and video-electroencephalography monitoring revealed a primarily intraventricular hypothalamic hamartoma and gelastic seizures occurring 20-30 times daily. The patient was treated with various regimens of antiepileptic medications for 16 months, but the seizures remained medically intractable. At 3 years of age, he underwent stereotactic laser ablation with an aim of disconnection of the lesion. The procedure was performed with the NeuroBlate SideFire probe. To the authors' knowledge, this is the first reported use of this technology for this procedure and serves as proof of concept. There were no perioperative complications, and 2 years postprocedure, the patient remains seizure free with marked behavioral and cognitive improvements.

Management of Epilepsy Due to Hypothalamic Hamartomas

A hypothalamic hamartoma consists of hyperplastic heterotopic tissue growing in a disorganized fashion. These lesions occur in about one per 50,000 to 100,000 people. Hypothalamic hamartomas can cause intrinsic epileptogenesis leading to gelastic seizures. Surrounding cortical structures may also develop secondary epileptogenesis. Persistent seizures caused by hypothalamic hamartomas can be debilitating and result in significant cognitive and behavioral impairment. Early recognition and treatment is important in controlling seizures and in preventing further cognitive deterioration. Some patients experience improved cognition and behavior following early treatment, suggesting that hypothalamic hamartomas represent a reversible epileptic encephalopathy. The outcome of epilepsy associated with these lesions has significantly evolved with the availability of new treatment techniques and an improved understanding of its pathogenesis. Increasing evidence supporting the role of hypothalamic hamartomas as a cause of gelastic seizures and secondary epileptogenesis has led to more frequent use of surgery as the definitive treatment. Several minimally invasive procedures have been devised, including neuroendoscopic approaches and different stereotactic radio and laser ablation techniques. Each of these techniques can lead to unique adverse events. We review the various classification schemes used to characterize hypothalamic hamartomas and the recommended surgical approaches for each subtype. We also review the literature for currently available treatment modalities and compare their efficacy in controlling seizures and their safety profiles.

MRI-Guided stereotactic laser ablation for epilepsy surgery: Promising preliminary results for cognitive outcome

Cognitive outcome data are reviewed with respect to the use of magnetic-resonance guided stereotactic laser ablation (SLA) as an epilepsy surgical procedure, with comparisons drawn to traditional open resection procedures. Cognitive outcome with stereotactic laser amygdalohippocampotomy (SLAH) appears better than open resection for several functions dependent on extra-mesial temporal lobe (TL) structures, including category-related naming, verbal fluency, and object/familiar person recognition. Preliminary data suggests episodic, declarative verbal memory can decline following SLAH in the language dominant hemisphere, although early findings suggest comparable or even superior outcomes compared with open resection. The hippocampus has long been considered a central structure supporting episodic, declarative memory, with epilepsy surgical teams attempting to spare it whenever possible. However, ample data from animal and human neuroscience research suggests declarative memory deficits are greater following broader mesial TL lesions that include parahippocampal gyrus and lateral TL inputs. Therefore, employing a neurosurgical technique that restricts the surgical lesion zone holds promise for achieving a better cognitive outcome. Focal SLA lesions outside of the amygdalohippocampal complex may impair select cognitive functions, although few data have been published in such patients to date. SLA is being effectively employed with adults and children with TL or lesional epilepsies across several U.S. epilepsy centers, which may simultaneously optimize cognitive outcome while providing a curative treatment for seizures.

Imaging of Laser Therapy in Epilepsy

BACKGROUND AND PURPOSE

MR-guided laser interstitial thermal therapy (MRgLITT) is an increasingly popular neuroablative method for the surgical treatment of epilepsy patients. This article intends to demonstrate the utility and pitfalls of imaging in the context of patient care with MRgLITT.

MATERIAL AND METHODS

A retrospective review of the medical records and imaging database with six illustrative cases selected to demonstrate the use of imaging throughout patient management with MRgLITT in diverse clinical situations and pathologies. A review of the knowledge in the literature was applied to the relevant points discussed.

RESULTS

Imaging findings were described in the setting of laser therapy in nonlesional epilepsy, mesial temporal sclerosis, dual pathology, periventricular nodular heterotopia, and schizencephaly. Discussion of imaging principles, potential pitfalls, as well as its use in the patient work-up and follow-up, is shown.

CONCLUSIONS

MRgLITT is an alternative minimally invasive therapy for refractory epilepsy, which is becoming widely sought for. Imaging plays a crucial role prior to, during, and after the procedure.

[Stereotactic laser thermocoagulation in epilepsy surgery]

In common with other stereotactic procedures, stereotactic laser thermocoagulation (SLT) promises gentle destruction of pathological tissue, which might become especially relevant for epilepsy surgery in the future. Compared to standard resection, no large craniotomy is necessary, cortical damage during access to deep-seated lesions can be avoided and interventions close to eloquent brain areas become possible. We describe the history and rationale of laser neurosurgery as well as the two available SLT systems (Visualase® and NeuroBlate®; CE marks pending). Both systems are coupled with magnetic resonance imaging (MRI) and MR thermometry, thereby increasing patient safety. We report the published clinical experiences with SLT in epilepsy surgery (altogether approximately 200 cases) with respect to complications, brain structural alterations, seizure outcome, neuropsychological findings and treatment costs. The rate of seizure-free patients seems to be slightly lower than for resection surgery. Due to the inadequate quality of studies, the neuropsychological superiority of SLT has not yet been unambiguously demonstrated.

Stereotactic Laser Ablation for Medically Intractable Epilepsy: The Next Generation of Minimally Invasive Epilepsy Surgery

Epilepsy is a common, disabling illness that is refractory to medical treatment in approximately one-third of patients, particularly among those with mesial temporal lobe epilepsy. While standard open mesial temporal resection is effective, achieving seizure freedom in most patients, efforts to develop safer, minimally invasive techniques have been underway for over half a century. Stereotactic ablative techniques, in particular, radiofrequency (RF) ablation, were first developed in the 1960s, with refinements in the 1990s with the advent of modern computed tomography and magnetic resonance-based imaging. In the past 5 years, the most recent techniques have used MRI-guided laser interstitial thermotherapy (LITT), the development of which began in the 1980s, saw refinements in MRI thermal imaging through the 1990s, and was initially used primarily for the treatment of intracranial and extracranial tumors. The present review describes the original stereotactic ablation trials, followed by modern imaging-guided RF ablation series for mesial temporal lobe epilepsy. The developments of LITT and MRI thermometry are then discussed. Finally, the two currently available MRI-guided LITT systems are reviewed for their role in the treatment of mesial temporal lobe and other medically refractory epilepsies.

How neuropsychology can improve the care of individual patients with epilepsy. Looking back and into the future

Some of the roots of current clinical neuropsychology go back to the early days of epilepsy surgery. Looking back a huge number of publications have dealt with cognition in epilepsy. The major factors driving this work were questions relating to surgery, antiepileptic drugs and, more recently, also to underlying pathology. However, most factors affecting cognition in epilepsy have been discerned many years ago. The body of neuropsychological literature in this field has accumulated much knowledge, raising the question why, apart from epilepsy surgery settings, neuropsychology has still not been fully integrated in the routine care of patients with epilepsy. This review on the occasion of Seizure's 25th anniversary attempts to summarize clinically relevant diagnostic advances following a question guided, modular, and evidence-based approach. In doing so, we hope to attract the interest of readers to an exciting mode of assessment which does not only have theoretical but also practical relevance. The comorbidities of epilepsy are becoming an increasingly relevant topic. It is now widely accepted that, while epilepsy may be defined by the occurrence of epileptic seizures, these seizures represent only one of several possible sources of cognitive impairment. It is well-established that there are complex interactions between epilepsy, cognition and behavior, and that both seizures and problems with cognition or behavior may result from a common underlying pathology requiring treatment. With this review we aim to demonstrate that neuropsychology can make a highly valuable contribution to the care of individual patients by contributing to the diagnostic process and by serving as a tool for the monitoring of disease and treatment, thereby improving the quality and safety of patient care. On a national, European, and international level, first efforts are being made to homogenize diagnostics across epilepsy centers and countries in order to achieve a common language and core standards. This should improve communication within and outside the speciality, and help to generate the data required to allow the field to make further progress.