Pure endoscopic management of epileptogenic hypothalamic hamartomas

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.

Gamma Knife Radiosurgery for Hypothalamic Hamartoma: A Multi-Institutional Retrospective Study on Safety, Efficacy, and Complication Profile

BACKGROUND AND OBJECTIVES

Gamma knife radiosurgery (GKRS) is a safe and effective treatment option for hypothalamic hamartomas (HH), but there is no consensus opinion on its timing, dosage, and follow-up. The aim of this study was to define the safety, efficacy, outcome, and complication profile of GKRS in this patient population.

METHODS

This retrospective multicentric study involved 39 patients with the mean age of 16 ± 14.84 years. Early seizures resulted in an earlier age of diagnosis in 97% of patients. At baseline, no endocrine abnormalities were seen in 75% of patients while 18.9% showed precocious puberty (PP). The median target volume was 0.55 cc (0.1-10.00 cc), and a median margin dose of 16 Gy (8.1-20.0 Gy) was delivered in a single session. All patients were evaluated for clinical, endocrinological, and radiological outcomes.

RESULTS

The median follow-up was 5 (0.1-15) years. The median target volume of the cohort was 0.55 (0.35-1.77) cc. The largest HH was of 10 cc. 24/39 (61.5%) were small HH (Regis I-III). At presentation, 94.8% patients suffered from seizures (87.18% with gelastic seizures). 7/39 patients (17.9%) were presented with both PP and epilepsy. Only one (2.6%) patient presented with PP alone. 29 patients had more than 3-year follow-up. All received ≥16 Gy targeting complete HH. 28% of patients showed regression in HH volume. Patients with Regis grade I-III and longer follow-up (>75 months) showed gradual improvement in seizures. 16/29 patients (55.2%) achieved good seizure control (Engel I/II) while 13 (44.8%) were in Engel III/IV status. Nine patients needed adjuvant treatment because of poor seizure control. Eight patients suffered from transient increase in seizures. One patient developed poikilothermia, and 2 patients developed new onset hormonal deficiency.

CONCLUSION

GKRS is a safe and effective modality for treatment of HH with significant improvement in seizure control with minimal disruption of endocrine profile. It provides an excellent safety, efficacy, and complication profile, especially for small HH. Latency of results and its adjuvant nature remain the areas of research and breakthroughs among contemporary treatment options.

Kindling in humans: Does secondary epileptogenesis occur?

The relevance of secondary epileptogenesis for human epilepsy remains a controversial subject decades after it was first described in animal models. Whether or not a previously normal brain region can become independently epileptogenic through a kindling-like process has not, and cannot, be definitely proven in humans. Rather than reliance on direct experimental evidence, attempts to answering this question must depend on observational data. In this review, observations based largely upon contemporary surgical series will advance the case for secondary epileptogenesis in humans. As will be argued, hypothalamic hamartoma-related epilepsy provides the strongest case for this process; all the stages of secondary epileptogenesis can be observed. Hippocampal sclerosis (HS) is another pathology where the question of secondary epileptogenesis frequently arises, and observations from bitemporal and dual pathology series are explored. The verdict here is far more difficult to reach, in large part because of the scarcity of longitudinal cohorts; moreover, recent experimental data have challenged the claim that HS is acquired consequent to recurrent seizures. Synaptic plasticity more than seizure-induced neuronal injury is the likely mechanism of secondary epileptogenesis. Postoperative running-down phenomenon provides the best evidence that a kindling-like process occurs in some patients, evidenced by its reversal. Finally, a network perspective of secondary epileptogenesis is considered, as well as the possible role for subcortical surgical interventions.

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.

Automated seizure onset zone locator from resting-state functional MRI in drug-resistant epilepsy

OBJECTIVE

Accurate localization of a seizure onset zone (SOZ) from independent components (IC) of resting-state functional magnetic resonance imaging (rs-fMRI) improves surgical outcomes in children with drug-resistant epilepsy (DRE). Automated IC sorting has limited success in identifying SOZ localizing ICs in adult normal rs-fMRI or uncategorized epilepsy. Children face unique challenges due to the developing brain and its associated surgical risks. This study proposes a novel SOZ localization algorithm (EPIK) for children with DRE.

METHODS

EPIK is developed in a phased approach, where fMRI noise-related biomarkers are used through high-fidelity image processing techniques to eliminate noise ICs. Then, the SOZ markers are used through a maximum likelihood-based classifier to determine SOZ localizing ICs. The performance of EPIK was evaluated on a unique pediatric DRE dataset (n = 52). A total of 24 children underwent surgical resection or ablation of an rs-fMRI identified SOZ, concurrently evaluated with an EEG and anatomical MRI. Two state-of-art techniques were used for comparison: (a) least squares support-vector machine and (b) convolutional neural networks. The performance was benchmarked against expert IC sorting and Engel outcomes for surgical SOZ resection or ablation. The analysis was stratified across age and sex.

RESULTS

EPIK outperformed state-of-art techniques for SOZ localizing IC identification with a mean accuracy of 84.7% (4% higher), a precision of 74.1% (22% higher), a specificity of 81.9% (3.2% higher), and a sensitivity of 88.6% (16.5% higher). EPIK showed consistent performance across age and sex with the best performance in those < 5 years of age. It helped achieve a ~5-fold reduction in the number of ICs to be potentially analyzed during pre-surgical screening.

SIGNIFICANCE

Automated SOZ localization from rs-fMRI, validated against surgical outcomes, indicates the potential for clinical feasibility. It eliminates the need for expert sorting, outperforms prior automated methods, and is consistent across age and sex.

Efficacy of endoscopic management of primary central nervous system lymphoma: a multicentric study and literature review

INTRODUCTION

To date, confined intra-ventricular localization of primary central nervous system lymphoma (PCNSL) has been usually managed with open surgical resection and/or stereotactic biopsy; nonetheless, the endoscopic approach to such localization can provide many advantages over standard microsurgery and/or stereotactic biopsy. Here we present our experience in managing such a rare pathology through the endoscopic approach.

METHOD

In order to gather more information about such a rare pathology, a retrospective multicentric study on a prospectively built database has been performed during a 5 year period. Ten different European centers have been involved.

RESULTS

A total of 60 patients, 25 women and 35 men, have been enrolled in the study. The mean age was 65.3 years. The mean lesion size was 40.3 mm. Among all selected patients, 40 (66.6%) had superficial lesions within the ventricle, whereas the remaining 20 (33.4%) had lesions involving/extending to deeper structures. All surgical procedures were uneventful and ETV was deemed necessary only in 20/60 cases.

CONCLUSION

In our experience, endoscopic management of intraventricular PCNSL is an effective option. It should be considered after a careful examination of neurological and immunological status, alternative options for diagnostic sampling, location of the lesion, and presence or absence of hydrocephalus. Endoscopic management could be considered as a safe and minimally invasive option to obtain: (a) a biopsy sample of the lesion for further diagnostic workup, (b) CSF diversion through third ventriculostomy or VP shunt for the management of hydrocephalus, and (c) insertion of ventricular access devices for long term medical management and whenever necessary as a rescue option for ventricular tap.

A Special Approach for Stereotactic Radiofrequency Thermocoagulation of Hypothalamic Hamartomas With Bilateral Attachments to the Hypothalamus: The Transthird Ventricular Approach to the Contralateral Attachment

BACKGROUND

Disconnection surgery for the treatment of epileptic hypothalamic hamartomas (HHs) is strategically difficult in cases with complex-shaped HHs, especially with bilateral hypothalamic attachments, despite its effectiveness.

OBJECTIVE

To evaluate the feasibility of a new approach for stereotactic radiofrequency thermocoagulation (SRT) using penetration of the third ventricle (SRT-TT) aiming to disconnect bilateral hypothalamic attachments in a single-staged, unilateral procedure.

METHODS

Ninety patients (median age at surgery, 5.0 years) who had HHs with bilateral hypothalamic attachments and were followed for at least 1 year after their last SRT were retrospectively reviewed.

RESULTS

Thirty-three patients underwent SRT-TT as initial surgery. Of the 58 patients after mid-2013 when SRT-TT was introduced, 33 underwent SRT-TT and 12 (20.7%) required reoperation (ReSRT), whereas 20 of 57 patients (35.1%) without SRT-TT underwent reoperation. Reoperation was required in significantly fewer patients after mid-2013 (n = 12 of 58, 20.7%) than before mid-2013 (n = 15 of 32, 46.9%) (P = .01). Final seizure freedoms were not different between before and after mid-2013 (gelastic seizure freedom, n = 30 [93.8%] vs n = 49 [84.5%] and other types of seizure freedom, n = 21 of 31 [67.7%] vs n = 32 of 38 [84.2%]). Persistent complications were less in SRT-TT than in ReSRT using the bilateral approach, but not significantly. However, hormonal replacement was required significantly more often in ReSRT using the bilateral approach (4 of 9, 44.4%) than in SRT-TT (3 of 32, 9.4%) (P = .01).

CONCLUSION

SRT-TT enabled disconnection of bilateral attachments of HHs in a single-staged procedure, which reduced the additional invasiveness of reoperation. Moreover, SRT-TT reduced damage to the contralateral hypothalamus, with fewer endocrinological complications than the bilateral approach.

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.

Case Report: Whole-Exome Sequencing of Hypothalamic Hamartoma From an Infant With Pallister-Hall Syndrome Revealed Novel de novo Mutation in the GLI3

Background: GLI-Kruppel family member 3 (GLI3), a zinc finger transcription factor of the sonic hedgehog pathway, is essential for organ development. Mutations in GLI3 cause several congenital conditions, including Pallister-Hall syndrome (PHS), which is characterized by polydactyly and hypothalamic hamartoma. Most patients are diagnosed soon after birth, and surgical removal of hypothalamic hamartoma in the very young is rarely performed because of associated risks.

Case presentation: A 7-month-old boy with PHS features, including a suprasellar lesion, bifid epiglottis, tracheal diverticulum, laryngomalacia, left-handed polydactyly and syndactyly, and omental hernia was referred to our service. His suprasellar lesion was partially removed, and whole-exome sequencing was applied to the resected tumor, his peripheral blood, and blood from his parents. Histopathology confirmed the diagnosis of hypothalamic hamartoma, and molecular profiling revealed a likely pathogenic de novo variant, c.2331C>G (p. H777Q), in GLI3. Magnetic resonance imaging follow-up 1 year later showed some residual tumor, and the patient experienced normal development post operation.

Conclusions: We presented a case of PHS that carries a novel GLI3 variant. Hypothalamic hamartoma showed a distinct genetic landscape from germline DNA. These data offer insights into the underlying etiology of hypothalamic hamartoma development in patients with PHS.

Pre-operative imaging and post-operative appearance of standard paediatric neurosurgical approaches: a training guide for neuroradiologists

A short-cut narrative review was conducted according to the SANRA guidelines to identify studies describing normal and abnormal postoperative radiological features of the most common paediatric neurosurgical procedures. Rather than focusing on the original pathology addressed by neurosurgical means, this review explored three main areas of operative neurosurgery: ventricular access, supratentorial & infratentorial craniotomies, and posterior fossa/craniocervical junction decompression. A total of twenty-three landmark papers were included for review based on their relevance to address the research question and serve as a practical guide for paediatric neuroradiology trainees and fellows. Accurate in text referencing of the ClinicalTrials.gov identifier, and weblink, has also been provided for all trials discussed in the results section. All the above is complemented by relevant iconography meant to describe a wide range of postoperative changes and early complications. Finally, the review is enriched by a discussion touching upon haemostatic agents, intentionally retained foreign bodies and the future of machine learning for neuroradiology reporting. Overall, the information presented in a systematic fashion will not only help trainees and fellows to deepen these topics and expand their knowledge in preparation for written and oral boards, but will also represent a useful resource for everyone including trained neuroradiologists and neurosurgeons themselves.

Gelastic seizures and the hypothalamic hamartoma syndrome: Epileptogenesis beyond the lesion?

The clinicoradiologic syndrome of hypothalamic hamartoma (HH) manifests with a variety of symptoms, including pharmacoresistant epilepsy with multiple seizure types, precocious puberty, behavioral disturbances, and cognitive impairment. Gelastic seizures are an early marker of epilepsy with HH in most of the cases. Despite a high variability, two major epilepsy phenotypes can be distinguished, based on electroclinical features: (i) focal seizures with epigastric or déjà-vu aura, loss of consciousness, and oroalimentary or gestural automatisms suggestive of temporal lobe involvement; and (ii) motor seizures with tonic, atonic, myoclonic, or versive phenomena, suggesting frontoparietal network involvement, with possible evolution toward an epileptic encephalopathy. The underlying physiopathologic mechanisms are not completely elucidated. The well-known intrinsic epileptogenicity of the HH represents the rationale for direct HH-aiming surgical procedures, with variable success in achieving seizure freedom. The concept of kindling-like secondary epileptogenesis has been suggested as a possible putative mechanism since the very beginnings of the hamartocentric era. Accordingly, a cortical area with enhanced epileptogenic properties due to an independent stage of secondary epileptogenesis would be responsible for seizures persisting after hamartoma ablation. However, recent intracerebral stereotactic EEG (SEEG) explorations demonstrated more complex, both reciprocal and hierarchical, relationships within the hypothalamo-cortical epileptogenic networks. Network formation may be due to either secondary epileptogenesis or widespread epileptogenicity present at the outset. A short time window from epilepsy onset to surgery seems to be crucial to cure epilepsy by direct surgery addressing a hamartoma. SEEG exploration may be reasonably proposed in cases where clinical data suggest an extension of the epileptogenic zone outside the limits of the HH, especially in focal seizures with impaired awareness and absence of gelastic seizures, or after a failure of the direct HH-aiming procedure.

Septo-optic dysplasia

Septo-optic dysplasia (SOD) or de Morsier's syndrome is a rare congenital disorder characterized by a classic triad of: (a) optic nerve hypoplasia, (b) agenesis of septum pellucidum and corpus callosum, and (c) hypoplasia of the hypothalamic-pituitary axis. This chapter will outline the key information regarding the etiology and epidemiology of this syndrome with a focus on its comprehensive management. Particular attention will be paid to the diagnostic stage and the most relevant differential diagnosis, before moving to the complexities of its treatment. In fact, although SOD is not curable, many aspects of this syndrome can be improved through a tailored multidisciplinary approach consisting in hormonal replacement, corrective ophthalmological surgery, management of epileptic seizures, and active neuropsychological support.

Surgical treatment of hypothalamic hamartomas

Hypothalamic hamartomas are aberrant masses, composed of abnormally distributed neurons and glia. Along endocrine and cognitive symptoms, they may cause epileptic seizures, including the specific gelastic and dacrystic seizures. Surgery is the treatment of drug-resistant hamartoma epilepsy, with associated positive results on endocrine, psychiatric, and cognitive symptoms. Recently, alternatives to open microsurgical treatment have been proposed. We review these techniques and compare their efficacy and safety. Open resection or disconnection of the hamartoma, either through pterional, transcallosal, or transventricular approach, leads to good epileptological control, but its high complication rate, up to 30%, limits its indications. The purely cisternal peduncular forms remain the only indication of open, pterional approach, while other strategies have been developed to overcome the neurological, endocrine, behavioral, or cognitive complications. Laser and radiofrequency thermocoagulation-based disconnection through robot-guided stereo-endoscopy has been proposed as an alternative to open microsurgical resection and stereotactic destruction. The goal is to allow safe and complete disconnection of a possibly complex attachment zone, through a single intraparenchymal trajectory which allows multiple laser or radiofrequency probe trajectory inside the ventricle. The efficacy was high, with 78% of favorable outcome, and the overall complication rate was 8%. It was especially effective in patients with isolated gelastic seizures and pure intraventricular hamartomas. Stereotactic radiosurgery has proved as efficacious and safer than open microsurgery, with around 60% of seizure control and a very low complication rate. Multiple stereotactic thermocoagulation showed very interesting results with 71% of seizure freedom and 2% of permanent complications. Stereotactic laser interstitial thermotherapy (LiTT) seems as effective as open microsurgery (from 76 to 81% of seizure freedom) but causes up to 20% of permanent complications. This technique has however been highly improved by targeting only the epileptogenic onset zone in the hamartoma, as shown on preoperative functional MRI, leading to an improvement of epilepsy control by 45% (92% of seizure freedom) with no postoperative morbidity. All these results suggest that the impact of the surgical procedure does not depend on purely technical matters (laser vs radiofrequency thermocoagulation or stereotactic vs robot-guided stereo-endoscopy) but relies on the understanding of the epileptic network, including inside the hamartoma, the aim being to plan an effective disconnection or lesion of the epileptogenic part while sparing the adjacent functional structures.

A Primer on Magnetic Resonance-Guided Laser Interstitial Thermal Therapy for Medically Refractory Epilepsy

Epilepsy surgery that eliminates the epileptogenic focus or disconnects the epileptic network has the potential to significantly improve seizure control in patients with medically intractable epilepsy. Magnetic resonance-guided laser interstitial thermal therapy (MRgLITT) has been an established option for epilepsy surgery since the US Food and Drug Administration cleared the use of MRgLITT in neurosurgery in 2007. MRgLITT is an ablative stereotactic procedure utilizing heat that is converted from laser energy, and the temperature of the tissue is monitored in real-time by MR thermography. Real-time quantitative thermal monitoring enables titration of laser energy for cellular injury, and it also estimates the extent of tissue damage. MRgLITT is applicable for lesion ablation in cases that the epileptogenic foci are localized and/or deep-seated such as in the mesial temporal lobe epilepsy and hypothalamic hamartoma. Seizure-free outcomes after MRgLITT are comparable to those of open surgery in well-selected patients such as those with mesial temporal sclerosis. Particularly in patients with hypothalamic hamartoma. In addition, MRgLITT can also be applied to ablate multiple discrete lesions of focal cortical dysplasia and tuberous sclerosis complex without the need for multiple craniotomies, as well as disconnection surgery such as corpus callosotomy. Careful planning of the target, the optimal trajectory of the laser probe, and the appropriate parameters for energy delivery are paramount to improve the seizure outcome and to reduce the complication caused by the thermal damage to the surrounding critical structures.