Surgical treatment of hypothalamic hamartomas

Abstract

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 thermo-coagulation 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 thermo-coagulation 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.

Significance of the electrophysiological border between hypothalamic hamartomas and the hypothalamus for the target of ablation surgery identified by intraoperative semimicrorecording

“…A recent review article on HH surgery also suggested that multiple radiofrequency small lesions have better efficacy and safety than LITT, probably due to the difficulty of the latter technique in targeting the whole lesion while sparing the adjacent structure. 24 Nevertheless, this review also implied the necessity of taking into account the recent advances of LITT.…”

“…5 To achieve this goal safely, clear demarcation between the HH and the hypothalamus is essential for creating an effective disconnection plane, as well as for avoiding additional damage to the hypothalamus. Because SRT has the disadvantage of not having a method of intraoperative monitoring for thermocoagulation area like MR thermometry in LITT, 24 accurate placement of the coagulation probe is crucial. Semimicrorecording showed the electrophysiological border between the hypothalamus and HH at the submillimeter level, which almost completely corresponded to the morphological border determined by MRI.…”

Pediatric Epilepsy Surgery in Focal and Generalized Epilepsy: Current Trends and Recent Advancements

“…40,41 Similarly, a cohort of children with generalized multiregional epileptic discharges on EEG associated with Lennox-Gastaut syndrome had good seizure outcomes and developmental quotient after resective surgery. 42 Children presenting with gelastic seizures due to HH have also had good outcomes from direct endoscopic removal, 43 radiation therapy, 44 and laser ablation. 45 Hence, the distinction between generalized and focal seizures as it pertains to surgical candidacy is less straightforward than previously recognized.…”

MR-gestützte stereotaktische Laserthermoablation eines hypothalamischen Hamartoms bei einer jungen Epilepsiepatientin: klinischer Verlauf und Kostenanalyse

“…Damit einhergehend, können hohe direkte, indirekt und intangible Kosten entstehen [5,6]. Zwar bietet eine epilepsiechirurgische Behandlung eine realistische Chance auf eine dauerhafte Anfallsfreiheit, birgt aufgrund der zentralen Lage des HH allerdings ein relevantes perioperatives Komplikationsrisiko, welches bei einer mikrochirurgischen Resektion zwischen 8 und 50 % liegt [7]. Zu den Komplikationen zählen Thalamusinfarkte, Gesichtsfelddefekte, endokrinologische Störungen und Gedächtnisprobleme [8].…”