Treatment modality for intractable epilepsy in hypothalamic hamartomatous lesions

Hypothalamic Hamartoma related epilepsy: A systematic review exploring clinical, neuropsychological, and psychiatric outcome after surgery

The post-surgical outcome for Hypothalamic Hamartoma (HH) related epilepsy in terms of seizure freedom (SF) has been extensively studied, while cognitive and psychiatric outcome has been less frequently reported and defined. This is a systematic review of English language papers, analyzing the post-surgical outcome in series of patients with HH-related epilepsy (≥5 patients, at least 6 months follow-up), published within January 2002-December 2022. SF was measured using Engel scale/equivalent scales. We looked at the outcome related to different surgical techniques, and HH types according to Delalande classification. We evaluated the neuropsychological and neuropsychiatric status after surgery, and the occurrence of post-surgical complications. Forty-six articles reporting 1318 patients were included, of which ten pediatric series. SF was reported in 686/1222 patients (56,1%). Delalande classification was reported in 663 patients from 24 studies, of which 70 were type I HH (10%), 320 were type II HH (48%), 189 were type III HH (29%) and 84 were type IV HH (13%). The outcome in term of SF was reported in 243 out of 663 patients. SF was reported in 12 of 24 type I HH (50%), 80 of 132 type II HH (60,6%), 32 of 59 type III HH (54,2%) and 12 of 28 type IV HH (42,9%). SF was reached in 129/262 (49,2%) after microsurgery, 102/199 (51,3%) after endoscopic surgery, 46/114 (40,6%) after gamma knife surgery, 245/353 (69,4%) after radiofrequency thermocoagulation, and 107/152 (70,4%) after MRI-guided laser interstitial thermal therapy. Hyperphagia/weight gain were the most reported surgical complications. Others were electrolyte alterations, diabetes insipidus, hypotiroidism, transient hyperthermia/poikilothermia. The highest percentage of memory deficits was reported after microsurgery, while hemiparesis and cranial nerves palsy were reported after microsurgery or endoscopic surgery. Thirty studies reported developmental delay/intellectual disability in 424/819 (51,7%) patients. 248/346 patients obtained a global improvement (72%), 70/346 were stable (20%), 28/346 got worse (8%). 22 studies reported psychiatric disorders in 257/465 patients (55,3%). 78/98 patients improved (80%), 13/98 remained stable (13%), 7/98 got worse (7%). Most of the patients had non-structured cognitive/psychiatric assessments. Based on the available data, the surgical management in patients with HH related epilepsy should be individualized, aiming to reach not only the best epilepsy result, but also the optimal cognitive and psychiatric outcome.

Seizure outcomes and safety profiles of surgical options for epilepsy associated to hypothalamic hamartomas. A systematic review and meta-analysis

PURPOSE

Several surgical options are available for treating hypothalamic hamartoma-related epilepsy but their respective efficacy and safety profiles are poorly defined.

METHODS

A literature search identified English-language articles reporting series of patients (minimum 3 patients with a follow-up ≥12 months) operated on by either microsurgery, endoscopic surgery, radiosurgery, radiofrequency thermocoagulation or laser interstitial thermal therapy for hypothalamic hamartoma-related epilepsy. The unit of analysis was each selected study. Pooled rates of seizure freedom and of neurological and endocrinological complications were analyzed using meta-analysis to calculate both fixed and random effects. The results of meta-analyses were compared.

RESULTS

Thirty-nine studies were included. There were 568 and 514 participants for seizure outcome and complication analyses, respectively. The pairwise comparison showed that: i) the proportion of seizure-free cases was significantly lower for radiosurgery as compared to microsurgery, radiofrequency thermocoagulation and laser ablation, and significantly lower for endoscopic surgery as compared to radiofrequency thermocoagulation; ii) the proportion of permanent hypothalamic dysfunction was significantly higher for microsurgery as compared to all other techniques, and significantly lower for endoscopic surgery as compared to radiofrequency thermocoagulation and laser ablation; iii) the incidence of permanent neurological disorders was significantly higher for microsurgery as compared to endoscopic surgery, radiosurgery and radiofrequency thermocoagulation, and significantly lower for radiosurgery as compared to laser ablation.

CONCLUSIONS

Minimally invasive surgical techniques, including endoscopic surgery, radiofrequency thermocoagulation and laser ablation, represent an acceptable compromise between efficacy and safety in the treatment of hypothalamic hamartoma-related epilepsy. Microsurgery and radiosurgery should be considered in carefully selected cases.

A novel technique for frame-based MR-guided laser ablation in an infant

Hypothalamic hamartomata (HH) not only are usually associated with drug-resistant epilepsy but can also cause precocious puberty and developmental delay. Gelastic seizures are the most common type of seizures. Magnetic resonance image (MRI)-guided laser interstitial thermal therapy (LiTT) is a technique whereby a laser fibre is stereotactically implanted into a target lesion and heat is used to ablate whilst tissue temperature is monitored using MRI thermography. MRI-guided LiTT has proven to be an effective and safe method to treat HH. To use the LiTT system, highly accurate stereotactic fibre implantation is required. This can be achieved by the use of frame-based or frameless neuronavigation techniques. However, these techniques generally involve rigid head immobilisation using cranial pin fixation. Patients need sufficient skull thickness to safely secure the pins and sufficient skull rigidity to prevent deformation. Hence, most of the clinical reports on the use of LiTT for children describe patients aged 2 years or older. We report a novel and practical technique of using a paste cast helmet to securely place a stereotactic frame in a 5-month-old infant with HH and drug-resistant epilepsy that allowed the successful application of MRI-guided LiTT.

Minimally Invasive Destructive, Ablative, and Disconnective Epilepsy Surgery

Conventional epilepsy surgery performed by microsurgical dissection typically requires large cranial working windows created with high-speed drills and lengthy incisions. In the past few decades, minimally invasive techniques have been developed with smaller incisions, comparable efficacy, shorter hospitalizations, and better safety profiles. These minimally invasive alternatives utilize stereotactic, ultrasonic, radiotherapeutic, and endoscopic techniques. Although not able to completely replace conventional surgery for all etiologies of epilepsy, these minimally invasive techniques have revolutionized modern epilepsy surgery and have been an invaluable asset to the neurosurgeon's repertoire. The endoscope has allowed for surgeons to have adequate visualization during resective and disconnective epilepsy surgeries using keyhole or miniature craniotomies. Modern stereotactic techniques such as laser interstitial thermal therapy and radiofrequency ablation can be used as viable alternatives for mesial temporal lobe epilepsy and can destroy lesional tissue deep areas without the approach-related morbidity of microsurgery such as with hypothalamic hamartomas. These stereotactic techniques do not preclude future surgery in the settings of treatment failure and have been used successfully after failed conventional surgery. Multiple ablation corridors can be performed in a single procedure that can be used for lesioning of large targets or to simplify treating multifocal epilepsies. These stereotactic techniques have even been used successfully to perform disconnective procedures such as hemispherotomies and corpus callosotomies. In patients unable to tolerate surgery, stereotactic radiosurgery is a minimally invasive option that can result in improved seizure control with minimal procedural risks. Advances in minimally invasive neurosurgery provide viable treatment options for drug-resistant epilepsy with quicker recovery, less injury to functional brain, and for patients that may otherwise not choose conventional surgery.

ILAE classification and definition of epilepsy syndromes with onset in neonates and infants: Position statement by the ILAE Task Force on Nosology and Definitions

The International League Against Epilepsy (ILAE) Task Force on Nosology and Definitions proposes a classification and definition of epilepsy syndromes in the neonate and infant with seizure onset up to 2 years of age. The incidence of epilepsy is high in this age group and epilepsy is frequently associated with significant comorbidities and mortality. The licensing of syndrome specific antiseizure medications following randomized controlled trials and the development of precision, gene-related therapies are two of the drivers defining the electroclinical phenotypes of syndromes with onset in infancy. The principal aim of this proposal, consistent with the 2017 ILAE Classification of the Epilepsies, is to support epilepsy diagnosis and emphasize the importance of classifying epilepsy in an individual both by syndrome and etiology. For each syndrome, we report epidemiology, clinical course, seizure types, electroencephalography (EEG), neuroimaging, genetics, and differential diagnosis. Syndromes are separated into self-limited syndromes, where there is likely to be spontaneous remission and developmental and epileptic encephalopathies, diseases where there is developmental impairment related to both the underlying etiology independent of epileptiform activity and the epileptic encephalopathy. The emerging class of etiology-specific epilepsy syndromes, where there is a specific etiology for the epilepsy that is associated with a clearly defined, relatively uniform, and distinct clinical phenotype in most affected individuals as well as consistent EEG, neuroimaging, and/or genetic correlates, is presented. The number of etiology-defined syndromes will continue to increase, and these newly described syndromes will in time be incorporated into this classification. The tables summarize mandatory features, cautionary alerts, and exclusionary features for the common syndromes. Guidance is given on the criteria for syndrome diagnosis in resource-limited regions where laboratory confirmation, including EEG, MRI, and genetic testing, might not be available.

[Stereotactic radiosurgery for epilepsy related to hypothalamic hamartoma]

Hypothalamic hamartoma (HH) is a dysplastic lesion fused with hypothalamus and followed by epilepsy, precocious puberty and behavioral disorders. Up to 50% of patients become free of seizures after surgery, but various complications occur in 1/4 of cases. Radiofrequency thermocoagulation, laser interstitial thermal therapy and stereotactic radiosurgery (SRS) are alternative treatment options.

OBJECTIVE

To define the indications for SRS in patients with HH and to clarify the irradiation parameters.

MATERIAL AND METHODS

Twenty-two patients with HH and epilepsy underwent SRS at the Moscow Gamma-knife Center. A retrospective analysis included 19 patients with sufficient follow-up data. Median age of patients was 11.5 years (range 1.3-25.8). The diameter of irradiated HHs ranged between 5.5 and 40.9 mm. In 8 (36%) cases, the volume of hamartoma exceeded 3 cm³. Mean prescribed dose was 18±2.0 Gy, mean prescribed isodose - 48±4.2%. Median follow-up period was 14.8 months (range 3.4 - 96.1).

RESULTS

Three (15.8%) patients were free of seizures. One patient (5.3%) improved dramatically after treatment with compete resolution of generalized seizures and experienced only rare emotional seizures (Engel IB). Eleven (57.8%) patients reported lower incidence of seizures. Severity and incidence of seizures were the same in 4 patients (21.1%). The best results were achieved in mean target dose over 20-22 Gy, minimal target dose over 7-10 Gy, covering by the prescribed dose of at least 70-80% of hamartoma volume, as well as in patients with the prescribed dose of 12 Gy delivered to almost entire volume of tumor. None patient had any complications after SRS.

CONCLUSION

SRS is safe regarding neurological, endocrine or visual disturbances. Careful patient selection for SRS makes it an effective option for HH-related epilepsy. The best candidates for SRS are children with seizures aged over 1 year, hamartoma <3 cm³ and area of fusion with hypothalamus <150 mm².

[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.

Surgery for Intractable Epilepsy in Pediatrics, a Systematic Review of Outcomes other than Seizure Freedom

To perform a systematic review evaluating reported outcomes for epilepsy surgery in pediatric patients with pharmacoresistant epilepsy beyond seizure control, including impact on quality of life, behavioral, neurocognitive outcomes as well as complications, and death. We reviewed articles from both EMBASE and MEDLINE/PubMed articles that met formal criteria (patients ≤18 years, those with intractable epilepsy, at least 5 patients in the case series, published in peer-reviewed journal). Each reviewer independently reviewed the articles and those with discrepancies were discussed and consensus was reached. Out of a total of 536 abstracts obtained from EMBASE and MEDLINE/PubMed searches combined with additional cross-referencing, a total of 98 manuscripts ultimately met all inclusion criteria. The manuscripts were divided into 3 outcomes categories: Quality of Life (16), Cognitive Outcomes (60), and Deficits and Complications (50). Several papers fell into more than 1 category. These were separated by surgical types and evaluated. We found that overall reporting in all domains was variable and inconsistent amongst the different studies. This systematic review highlights the lack of completeness in reporting outcomes and complications involving pediatric epilepsy surgery and discordant results. This underscores the importance of multicenter systematic prospective data collection in pediatric patients who undergo pediatric epilepsy surgery.

Successful Endoscopic Disconnection for Hypothalamic Hamartomas in a Child with Gelastic Seizures: An Unusual Case in a Resource-Scare Setting

Although the endoscopic disconnection surgery for the hamartomas was previously shown as a safe and effective treatment strategy in eliminating gelastic epilepsy, to date, there was no convincing evidence with this procedure in the resource-scare settings. We discuss an unusual case of a 7-year-old child who suffered from pharmacoresistant gelastic seizures was surgically treated with the endoscopic disconnection of the hypothalamic hamartomas. The patient underwent endoscopic surgery through the left ventricle approach to disconnect the lesion of the hypothalamus. Immediately after surgery, the patient’s clinical laughter was eliminated with no complications. From the initial experience at our center, successful outcome of this case contributes to supporting the solid evidence in choosing the right treatment approach for the hypothalamus in subsequent cases, towards not only Vietnam but also the countries having similar resource-scare conditions.

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.

Hypothalamic Hamartoma, Gray Matter Heterotopia, and Polymicrogyria in a Boy: Case Report and Literature Review

BACKGROUND

Hypothalamic hamartomas (HHs) are rare, and it is even rarer when combined with gray matter heterotopia (GMH) and polymicrogyria (PMG).

CASE DESCRIPTION

A 5-year-old boy with HH, GMH, and PMG was retrospectively evaluated. The clinical data, including the symptoms, examinations, diagnosis, and treatment, were collected. The patient had a chief complaint of gelastic seizures and intellectual deficiency. Brain magnetic resonance imaging showed HH, paraventricular nodular heterotopia, and PMG. Video electroencephalographs were normal. The patient underwent resection of the HH via transcallosal transseptal interforniceal approach. Seizures disappeared immediately after complete resection of HH, and the intellectual development improved.

CONCLUSIONS

In this extremely rare case, resection of the HH eliminated the symptoms. Nonetheless, we still need to be cautious about the possible epilepsy that may be caused by GMH and PMG.

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.

Endoscopic Treatment of Hypothalamic Hamartomas

Hypothalamic hamartoma (HH) is a benign indolent lesion despite the presentation of refractory epilepsy. Behavioral disturbances and endocrine problems are additional critical symptoms that arise along with HHs. Due to its nature of generating epileptiform discharge and spreading to cortical region, various management strategies have been proposed and combined. Surgical approaches with open craniotomy or endoscopy, stereotactic approaches with radiosurgery and gamma knife surgery or radiofrequency thermos-coagulation, and laser ablation have been introduced. Topographical dimension and the surgeon’s preference are key factors for treatment modalities. Endoscopic disconnection has been one of the most favorable options performed in treating HHs. Here we discuss presurgical evaluation, patient selection, surgical procedures, and complications.

Pure endoscopic management of epileptogenic hypothalamic hamartomas

Hypothalamic hamartomas (HH) are rare congenital malformations located in the region of the tuber cinereum and third ventricle. Their usual clinical presentation is characterized by gelastic/dacrystic seizures which often become pharmaco-resistant and progress to secondary focal/generalized intractable epilepsy causing mostly in children cognitive and behavioral problems (particularly in cases of progressive epileptic encephalopathy) and precocious puberty. Whereas gelastic seizures can be surgically controlled either by resection of the lesion or disconnection (tissue-destructive) procedures, aimed at functionally prevent the spreading of the epileptic burst; generalized seizures tend to respond better to HH excision rather than isolated neocortical resections, which generally fail to control them. Prospective analysis of 14 consecutive patients harboring HH treated in an 8-year period; 12 patients had unilateral and two bilateral HH. All patients were managed by pure endoscopic excision of the HH. The mean operative time was 48 min and mean hospital stay was 2 days; perioperative blood loss was negligible in all cases. Two patients showed a transient diabetes insipidus (DI); no transient or permanent postoperative neurological deficit or memory impairment was recorded. Complete HH excision was achieved in 10/14 patients. At a mean follow-up of 48 months, no wound infection, meningitis, postoperative hydrocephalus, and/or mortality were recorded in this series of patients. Eight patients became seizure free (Engel class I), 2 other experienced worthwhile improvement of disabling seizures (Engel class II); 2 patients were cured from gelastic attacks while still experiencing focal dyscognitive seizures; and 2, having bilateral HH (both undergoing unilateral HH excision), did not experience significant improvement and required later on a temporal lobectomy coupled to amygdalohyppocampectomy. Overall, the followings resulted to be predictive factors for better outcomes in terms of seizure control: (1) cases of unilateral, Delalande class B, HH, (2) shorter history of epilepsy. Endoscopic resection of HH proved, in our series, to be effective in achieving complete control or in reducing the frequency of seizures. Furthermore, this approach has confirmed its minimally invasive nature with a very low morbidity rate: of note, it allowed to better preserve short-term memory and hypothalamic function.

Transcranial magnetic resonance-guided focused ultrasound for temporal lobe epilepsy: a laboratory feasibility study

OBJECTIVE In appropriate candidates, the treatment of medication-refractory mesial temporal lobe epilepsy (MTLE) is primarily surgical. Traditional anterior temporal lobectomy yields seizure-free rates of 60%-70% and possibly higher. The field of magnetic resonance-guided focused ultrasound (MRgFUS) is an evolving field in neurosurgery. There is potential to treat MTLE with MRgFUS; however, it has appeared that the temporal lobe structures were beyond the existing treatment envelope of currently available clinical systems. The purpose of this study was to determine whether lesional temperatures can be achieved in the target tissue and to assess potential safety concerns. METHODS Cadaveric skulls with tissue-mimicking gels were used as phantom targets. An ablative volume was then mapped out for a "virtual temporal lobectomy." These data were then used to create a target volume on the InSightec ExAblate Neuro system. The target was the amygdala, uncus, anterior 20 mm of hippocampus, and adjacent parahippocampal gyrus. This volume was approximately 5cm³. Thermocouples were placed on critical skull base structures to monitor skull base heating. RESULTS Adequate focusing of the ultrasound energy was possible in the temporal lobe structures. Using clinically relevant ultrasound parameters (power 900 W, duration 10 sec, frequency 650 kHz), ablative temperatures were not achieved (maximum temperature 46.1°C). Increasing sonication duration to 30 sec demonstrated lesional temperatures in the mesial temporal lobe structures of interest (up to 60.5°C). Heating of the skull base of up to 24.7°C occurred with 30-sec sonications. CONCLUSIONS MRgFUS thermal ablation of the mesial temporal lobe structures relevant in temporal lobe epilepsy is feasible in a laboratory model. Longer sonications were required to achieve temperatures that would create permanent lesions in brain tissue. Heating of the skull base occurred with longer sonications. Blocking algorithms would be required to restrict ultrasound beams causing skull base heating. In the future, MRgFUS may present a minimally invasive, non-ionizing treatment of MTLE.

How would we deal with hypothalamic hamartomas?

Hypothalamic hamartoma (HH) is usually associated with refractory epilepsy, cognitive impairment, and behavioral disturbance. There is now increasing evidence that HH can be treated effectively with a variety of neurosurgical approaches. Treatment options for intractable gelastic seizure in HH patients include direct open surgery with craniotomy, endoscopic surgery, radiosurgery with gamma knife and stereotactic radiofrequency thermocoagulation. Selection of treatment modalities depends on type and size of the HH and the surgeon’s preference. Two surgical techniques, resection and disconnection, had been described with favorable outcomes. Pretreatment evaluation, patient selection, surgical techniques, complications, and possible selection of treatment are discussed.

Endoscopic disconnection of hypothalamic hamartomas: safety and feasibility of robot-assisted, thulium laser-based procedures

OBJECT

Hypothalamic hamartomas (HH) may induce drug-resistant epilepsy (DRE), thereby requiring surgical treatment. Conventionally, treatment is aimed at removing the lesion, but a disconnection procedure has been shown to be safer and at least as effective. The thulium laser (Revolix) has been recently introduced in urological endoscopy because of its ability to deliver a smooth cut with good control of the extent of tissue damage. The authors sought to analyze the safety and efficacy of the thulium 2-μm laser applied through navigated, robot-assisted endoscopy in disconnection surgery for HHs.

METHODS

Twenty patients with HH who were drug resistant were treated during a 12-month period. Conventional disconnection by monopolar coagulation (endoscopic electrode) was performed in 13 patients, and thulium laser disconnection was performed in the remaining 7 patients. The endoscope was inserted into the ventricle contralateral to the attachment of the HH on the third ventricular wall. Results in terms of safety, efficacy, and ease of use of the instrument were analyzed.

RESULTS

All 20 patients achieved a satisfactory postoperative Engel score (Classes I-III). At 12 months, the Engel class was I or II in 8 of 13 patients (61.5%) who underwent monopolar coagulation and in 6 of 7 patients (85.7%) who underwent laser disconnection (p = 0.04). Seven of 13 patients (53.8%) who underwent monopolar coagulator disconnection and 2 of 7 patients (28.6%) who underwent laser disconnection had immediate postoperative complications. At the 3-month follow-up, only 2 patients (15.4%) treated by coagulation still experienced mild surgery-related recent memory deficits. No complications persisted at the 12-month follow-up.

CONCLUSIONS

The disconnection procedure is a safe and effective treatment strategy to treat drug-resistant epilepsy in patients with HHs. With the limitations of initial experience and a short-term follow-up, it appears that the thulium 2-μm laser has the technical features to replace the standard coagulation in this procedure.

Intraoperative use of high-field MRI in hypothalamic hamartomas associated with epilepsy: clinico-pathological presentation of five adult patients

BACKGROUND

Hypothalamic harmartomas (HHs) are either occasionally associated with medically intractable epileptic syndromes or precocious puberty. Due to the extraordinary location and the expansive intra-axial growth, surgical resection is difficult and challenging without causing severe neurological, hypothalamic or endocrinological deficits, which account for higher mortality and morbidity.

METHODS

We present a series of five adult patients with drug-resistant epilepsy who had been operated on for HH using neuronavigation and intraoperative 1.5-T magnetic resonance imaging (MRI). In this retrospective investigation, we compared our surgical strategy and postoperative results to existing series.

RESULTS

During surgery, we identified remnant HH in the first intraoperative MRI control scan in three out of five patients. After re-segmentation of the residual lesion using neuronavigation, complete resection was achieved in two of the three patients as confirmed by final intraoperative and late follow-up MRI, raising the rate of total resections to four out of five patients. Two patients died during the observation period. One patient suffered from a permanent third nerve palsy and one from a transient monoparesis of the left arm. New endocrinological disturbances included diabetes insipidus centralis in two and secondary hypothyroidism and hypogonadism in one patient. Four out of five patients had favourable seizure control (Engel I or II) after 64.8 (34-83) months of mean follow-up.

CONCLUSIONS

Neuronavigation and intraoperative MRI are valuable tools to encounter difficulties while performing surgery in patients with HHs. Intraoperative resection control increases the amount of maximum resection.

Hypothalamic hamartoma simulating a suprasellar arachnoid cyst: resolution of precocious puberty following microsurgical lesion resection

Hypothalamic hamartomas (HHs) are rare developmental lesions arising from the inferior hypothalamus that may cause gelastic seizures and central precocious puberty. Cystic changes in HHs are rare, usually occurring in giant lesions. The authors describe an unusual case of cystic HH masquerading as a suprasellar arachnoid cyst in an 18-month-old girl presenting with precocious puberty. Microsurgical removal of the lesion led to complete resolution of the precocious puberty on long-term follow-up. This case is the first reported HH with pathological demonstration of corticotropin-releasing hormone immunostaining in the solid tumor and glial cells in the cyst wall of the lesion. The clinical and radiological characteristics of HHs are reviewed, along with the unique surgical strategies used to manage cystic lesions in the suprasellar region.

Classification of hypothalamic hamartoma and prognostic factors for surgical outcome

OBJECTIVES

The main aims of this study were to classify patients with hypothalamic hamartoma (HH) based on neuroimaging features and describe the clinical manifestations of HH.

MATERIALS AND METHODS

A retrospective review of 214 consecutive patients with HH treated in Beijing Tiantan Hospital was performed.

RESULTS

HH were diagnosed and divided into Types I-IV based on MRI. Types I and II were defined as the HH attached to the floor of the third ventricle with narrow (Type I) or broad (Type II) interfaces. Type III ('straddling') was defined by the HH extending into the third ventricle and interpeduncular cistern. Type IV was defined as the HH located totally within the third ventricle. The percent distribution of patients was 35.9% Type I, 12.1% Type II, 40.7% Type III, and 11.2% Type IV. The percentage of patients with precocious puberty was highest in Type I (81.8%). The percentage of patients with gelastic seizures was highest in Type IV (91.7%). After surgery, 20% (1/5) of patients with Type II HH, 48.8% (20/42) with Type III, and 91.7% (11/12) with Type IV were free of epileptic seizures. Significant prognostic factors for surgical outcome were HH size, surgical approach, and resection level.

CONCLUSIONS

The clinical manifestations of HH are correlated with the topology of the HH in relation to the hypothalamus. Our results suggest that patients with Type IV HH have the best outcome from surgery and neurosurgeons should be cautious about performing surgery on patients with Type II and Type III HH.

Hypothalamic hamartomas. Part 2. Surgical considerations and outcome

Hypothalamic hamartomas are uncommon developmental heterotopic masses composed of an intermixed array of neurons, glia, and myelinated fibers closely associated with the mammillary bodies. Gelastic seizures, the hallmark feature of hypothalamic hamartomas, commonly present in early childhood. However, patients usually also display a disabling clinical syndrome, which may include various other types of refractory seizures with secondary generalization together with progressive cognitive, behavioral, and psychiatric dysfunction. The hamartoma itself has been unequivocally shown to be intrinsically epileptogenic. Over the past 2 decades there has been considerable effort to develop neurosurgical techniques to treat the epileptic syndrome effectively as well as to improve the neurocognitive and behavioral outcome.

Radiosurgery for epilepsy: clinical experience and potential antiepileptic mechanisms

Stereotactic radiosurgery, well established in the noninvasive treatment of focal lesions that are otherwise difficult to access through open surgery, is an emerging technology in the treatment of focal epileptic lesions. Recent studies suggest that seizures from hypothalamic hamartomas and mesial temporal lobe epilepsy remit at clinically significant rates with radiosurgery, but large variations among different studies have raised questions about appropriate treatment protocols and mechanisms. Proposed anticonvulsant mechanisms include neuromodulatory effects or ischemic necrosis of epileptic tissue. An ongoing trial that directly compares efficacy, morbidities, and cost of radiosurgery versus open surgery for mesial temporal lobe epilepsy is underway.

Treatment modalities for intractable epilepsy in hypothalamic hamartoma

Hypothalamic hamartoma (HH) is usually associated with refractory epilepsy, cognitive impairment, and behavioral disturbance. There is now increasing evidence that HH can be treated effectively with a variety of neurosurgical approaches. Treatment options for intractable gelastic seizure in HH patients include direct open surgery with craniotomy, endoscopic surgery, radiosurgery with gamma knife (GKS) and stereotactic radiofrequency thermocoagulation. Selection of treatment modalities depends on type and size of the HH and the surgeon's preference. Two surgical techniques, resection and disconnection, had been described with favorable outcomes. Pretreatment evaluation, patient selection, surgical techniques, complications, and possible selection of treatment are discussed in this chapter.

Surgical treatment for refractory epilepsy: review of patient evaluation and surgical options

Treatment of epilepsy often imposes an exposure to various antiepileptic drugs and requires long-term commitment and compliance from the patient. Although many new medications are now available for the treatment of epilepsy, approximately 30% of epilepsy patients still experience recurrent seizures and many experience undesirable side effects. Treatment of epilepsy requires a multidisciplinary approach. For those patients with medically refractory seizures, surgical treatment has increased in prevalence as techniques and devices improve. With increased utilization, proper patient selection has become crucial in evaluating appropriateness of surgical intervention. Epilepsy syndromes in which surgery has shown to be effective include mesial temporal sclerosis, cortical dysplasia, many pediatric epilepsy syndromes, and vascular malformations. Monitoring in an epilepsy monitoring unit with continuous scalp or intracranial EEG is an important step in localization of seizure focus. MRI is the standard imaging technique for evaluation of anatomy. However, other imaging studies including SPECT and PET have become more widespread, often offering increased diagnostic value in select situations. In addition, as an alternative or adjunct to surgical resection, implantable devices such as vagus nerve stimulators, deep brain stimulators, and direct brain stimulators could be useful in seizure treatment.

Transendoscopic intraoperative recording of gelastic seizures from a hypothalamic hamartoma

OBJECT

The differential diagnosis of hypothalamic masses in children includes hamartomas, which are associated with gelastic seizures and endocrine dysfunction. The purpose of this study was to utilize transendoscopic electroencephalography (EEG) recording at the time of tissue biopsy to further assist in diagnosis, determination of prognosis, and treatment planning.

METHODS

We present the case of an infant with gelastic seizures and a large hypothalamic mass lesion. Despite a clinical and radiographic presentation typical of hypothalamic hamartoma (HH), slight growth on serial imaging raised concern for a diagnosis of intrinsic neoplasm. Biopsy of the lesion was recommended.

RESULTS

Transventricular, endoscopic biopsy, was undertaken, with concurrent intraoperative, transendoscopic EEG recording using a standard epilepsy depth recording macroelectrode. Numerous electrographic seizures were recorded. Histopathology revealed a HH.

CONCLUSION

This is the first report of intraoperative macroelectrode recording of electrographic seizures transendoscopically from a HH. This technique may prove useful for diagnosis, prognosis and treatment planning, as well as to guide transendoscopic therapeutic interventions for HH.

Synchronous occurrence of a hemorrhagic hypothalamic hamartoma and a suprasellar teratoma

Hypothalamic hamartomas have been reported to coexist with lesions like Rathke's cleft cyst and arachnoid cysts in the suprasellar or temporo-sylvian regions. This is the first report in indexed literature describing its association with a suprasellar teratoma. A 7-year-old girl presented with long-standing precocious puberty and generalized tonic-clonic seizures and recent-onset raised intracranial pressure. MRI done prior to the onset of symptomatic raised intracranial pressure revealed 2 distinct lesions in the suprasellar region. One was a midline, pedunculated lesion arising from the hypothalamus, with evidence of an old bleed within it. A separate lesion, with a wide base near the tuberculum sellae and a posteriorly directed conical tip, was noted in an adjacent sagittal cut. CT scan done at the time of admission demonstrated a re-bleed in the suprasellar region with blood in the lateral and third ventricles and gross hydrocephalus. The child was taken up for a ventriculoperitoneal shunt followed by complete excision of the lesions. Histopathologic examination confirmed the pedunculated lesion to be a hypothalamic hamartoma with evidence of hemorrhage, and the other to be a mature teratoma. Postoperative MRI confirmed complete excision of both the lesions. The child reported regression of precocious puberty and remained seizure-free until the last follow-up 6 months after surgery. A hypothesis based on a dysontogenetic mechanism is discussed to explain the unusual occurrence of the dual, seemingly unrelated pathologies. Hemorrhage into the hamartoma was an added oddity in this case.

Minimally invasive magnetic resonance imaging-guided stereotactic radiofrequency thermocoagulation for epileptogenic hypothalamic hamartomas

OBJECTIVE

To validate the safety and efficacy of magnetic resonance imaging (MRI)-guided stereotactic radiofrequency thermocoagulation (SRT) for epileptogenic hypothalamic hamartoma (HH), we evaluated surgical outcomes and revised the MRI classification.

METHODS

We retrospectively reviewed 25 consecutive patients with HH (age range, 2-36 years; mean age, 14.8 years) with gelastic seizures. Other seizure types were exhibited in 22 patients (88.0%), precocious puberty in 8 (32.0%), behavioral disorder in 10 (40.0%), and mental retardation in 14 (56.0%). We classified HH into 3 subtypes according to coronal MRI: intrahypothalamic, parahypothalamic, and mixed hypothalamic type. Maximum diameter ranged from 8 to 30 mm (mean, 15.3 mm). All patients underwent SRT (74 degrees C, 60 seconds) for HH.

RESULTS

HH subtype and size were correlated with precocious puberty, mental retardation, and behavioral disorder. Thirty-one SRT procedures were performed, requiring 1 to 8 tracks (mean, 3.8 tracks) and involving 1 to 18 lesions (mean, 7.2 lesions). There were no adaptive limitations, regardless of size or subtype. Mixed-type HHs needed more tracks and more lesions. No permanent complications persisted after SRT, and gelastic seizures disappeared in all but 2 patients. Complete seizure freedom was achieved in 19 patients (76.0%). These patients had not only disappearance of all seizure types and behavioral disorder but also intellectual improvement.

CONCLUSION

The present SRT procedure has favorable efficacy and invasiveness and has no adaptive limitations. SRT should therefore be considered before adulthood. The new HH classification is useful to understand clinical symptoms and to determine surgical strategies.

A review on the management of epilepsy associated with hypothalamic hamartomas

INTRODUCTION

Hypothalamic hamartomas are rare congenital malformations located in the region of the tuber cinereum and third ventricle. Patients may be asymptomatic, but the usual presentation is gelastic seizures, precocious puberty, and/or developmental delay.

CLINICAL PRESENTATION

Without surgical intervention, the gelastic seizures, which are typically present in childhood, may progress to other seizure types, including generalized epilepsy, and are generally refractory to antiepileptic drugs.

SUMMARY

This review will discuss the clinical and electrophysiologic aspects of these lesions, as well as treatment options, including surgery, endoscopy, and radiosurgery.