Introduction: Hypothalamic hamartomas (HH) are non-neoplastic lesions that have an estimated incidence of 1/200,000 and commonly present with precocious puberty, behavioral impairment, and gelastic seizures. Surgical resection can reduce seizure frequency and halt behavioral and cognitive decline. However, open surgery is associated with significant morbidity and mortality.

Methods: We present the case of a 22-month-old boy with a hypothalamic hamartoma who presented with medically intractable gelastic seizures, autism spectrum disorder, and global developmental delay. At 38 months of age, the patient underwent stereotactic laser-induced thermal therapy (LITT) using magnetic resonance thermal image mapping (MRgLITT) with the NeuroBlate® Systems SideFire™ probe, with an aim of disconnection of the lesion. This case marks the first such use of this technology.

Results: There were no perioperative complications and two years post-procedure the patient remains seizure-free with marked behavioral and cognitive improvements.

Conclusions: This is the first reported use of NeuroBlate® Side-Fire Probe technology to successfully treat a pediatric patient with HH, resulting in complete remission of seizures via disconnection. Although results should be interpreted with caution due to limited experience with only one patient, they merit further study into the safety and long-term efficacy of HH disconnection and potentially other epileptogenic foci using NeuroBlate® technology. This case serves as proof of concept of ability to disconnect such lesions without significant heat-sink or injury to surrounding tissues via transmission of energy via CSF.

Patient Care: We used the NeuroBlate® Systems SideFire™ probe in the successful disconnection of a HH in a pediatric patient, which resulted in the complete seizure remission. Although the safety and long-term efficacy of this approach merit further study in a larger population, our novel technique represents a potential option for the successful treatment of epileptogenic foci. This technique could result in greater rates of seizure reduction than those offered by current surgical approaches.

Learning Objectives: By the conclusion of this session, participants should be able to: 1) Describe in detail a new and exciting procedure for treatment of hypothalamic hamartomas. 2) Understand the importance of achieving seizure freedom. 3) Have a better understanding of the management and surgical options in patients with hypothalamic hamartomas

References: 1. Alves C, Barbosa V, Machado M. Giant hypothalamic hamartoma: case report and literature review. Child's nervous system : ChNS : official journal of the International Society for Pediatric Neurosurgery. Mar 2013;29(3):513-516. 2. Kerrigan JF, Ng YT, Chung S, Rekate HL. The hypothalamic hamartoma: a model of subcortical epileptogenesis and encephalopathy. Seminars in pediatric neurology. Jun 2005;12(2):119-131.3. Berkovic SF, Arzimanoglou A, Kuzniecky R, Harvey AS, Palmini A, Andermann F. Hypothalamic hamartoma and seizures: a treatable epileptic encephalopathy. Epilepsia. Jul 2003;44(7):969-973.4. Pati S, Sollman M, Fife TD, Ng YT. Diagnosis and management of epilepsy associated with hypothalamic hamartoma: an evidence-based systematic review. Journal of child neurology. Jul 2013;28(7):909-916.5. Tovar-Spinoza Z, Carter D, Ferrone D, Eksioglu Y, Huckins S. The use of MRI-guided laser-induced thermal ablation for epilepsy. Child's nervous system : ChNS : official journal of the International Society for Pediatric Neurosurgery. Nov 2013;29(11):2089-2094. 6. Wilfong AA, Curry DJ. Hypothalamic hamartomas: optimal approach to clinical evaluation and diagnosis. Epilepsia. Dec 2013;54 Suppl 9:109-114. 7. Rolston JD, Chang EF. Stereotactic Laser Ablation for Hypothalamic Hamartoma. Neurosurgery clinics of North America. Jan 2016;27(1):59-67. 8. Brandmeir N, Acharya V, Sather M. Robot Assisted Stereotactic Laser Ablation for a Radiosurgery Resistant Hypothalamic Hamartoma. Cureus. Apr 21 2016;8(4):e581. 9. Burrows AM, Marsh WR, Worrell G, et al. Magnetic resonance imaging-guided laser interstitial thermal therapy for previously treated hypothalamic hamartomas. Neurosurgical focus. Oct 2016;41(4):E8. 10. Sloan AE, Ahluwalia MS, Valerio-Pascua J, et al. Results of the NeuroBlate System first-in-humans Phase I clinical trial for recurrent glioblastoma: clinical article. Journal of neurosurgery. Jun 2013;118(6):1202-1219. 11. Valdueza JM, Cristante L, Dammann O, et al. Hypothalamic hamartomas: with special reference to gelastic epilepsy and surgery. Neurosurgery. Jun 1994;34(6):949-958; discussion 958. 12. Freeman JL. The anatomy and embryology of the hypothalamus in relation to hypothalamic hamartomas. Epileptic disorders : international epilepsy journal with videotape. Dec 2003;5(4):177-186.13. Arita K, Ikawa F, Kurisu K, et al. The relationship between magnetic resonance imaging findings and clinical manifestations of hypothalamic hamartoma. Journal of neurosurgery. Aug 1999;91(2):212-220.14. Kuzniecky R, Guthrie B, Mountz J, et al. Intrinsic epileptogenesis of hypothalamic hamartomas in gelastic epilepsy. Annals of neurology. Jul 1997;42(1):60-67.15. Berkovic SF, Kuzniecky RI, Andermann F. Human epileptogenesis and hypothalamic hamartomas: new lessons from an experiment of nature. Epilepsia. Jan 1997;38(1):1-3.16. Maixner W. Hypothalamic hamartomas--clinical, neuropathological and surgical aspects. Child's nervous system : ChNS : official journal of the International Society for Pediatric Neurosurgery. Aug 2006;22(8):867-873. 17. Palmini A, Chandler C, Andermann F, et al. Resection of the lesion in patients with hypothalamic hamartomas and catastrophic epilepsy. Neurology. May 14 2002;58(9):1338-1347. 18. Freeman JL, Harvey AS, Rosenfeld JV, Wrennall JA, Bailey CA, Berkovic SF. Generalized epilepsy in hypothalamic hamartoma: evolution and postoperative resolution. Neurology. Mar 11 2003;60(5):762-767. 7 19. Delalande O, Fohlen M. Disconnecting surgical treatment of hypothalamic hamartoma in children and adults with refractory epilepsy and proposal of a new classification. Neurologia medico-chirurgica. Feb 2003;43(2):61-68. 20. de Almeida AN, Fonoff ET, Ballester G, Teixeira MJ, Marino R, Jr. Stereotactic disconnection of hypothalamic hamartoma to control seizure and behavior disturbance: case report and literature review. Neurosurgical review. Jul 2008;31(3):343-349.21. Calisto A, Dorfmuller G, Fohlen M, Bulteau C, Conti A, Delalande O. Endoscopic disconnection of hypothalamic hamartomas: safety and feasibility of robot-assisted, thulium laser-based procedures. Journal of neurosurgery. Pediatrics. Dec 2014;14(6):563-572.22. Arroyo S, Lesser RP, Gordon B, et al. Mirth, laughter and gelastic seizures. Brain : a journal of neurology. Aug 1993;116 ( Pt 4):757-780.23. Arita K, Kurisu K, Iida K, et al. Subsidence of seizure induced by stereotactic radiation in a patient with hypothalamic hamartoma. Case report. Journal of neurosurgery. Oct 1998;89(4):645-648.24. Regis J, Bartolomei F, de Toffol B, et al. Gamma knife surgery for epilepsy related to hypothalamic hamartomas. Neurosurgery. Dec 2000;47(6):1343-1351; discussion 1351-1342. 25. Regis J, Scavarda D, Tamura M, et al. Gamma knife surgery for epilepsy related to hypothalamic hamartomas. Seminars in pediatric neurology. Jun 2007;14(2):73-79.26. Quigg M, Harden C. Minimally invasive techniques for epilepsy surgery: stereotactic radiosurgery and other technologies. Journal of neurosurgery. Dec 2014;121 Suppl:232-240.27. Heisterkamp J, van Hillegersberg R, Zondervan PE, JN IJ. Metabolic activity and DNA integrity in human hepatic metastases after interstitial laser coagulation (ILC). Lasers in surgery and medicine. 2001;28(1):80-86.28. McNichols RJ, Gowda A, Kangasniemi M, Bankson JA, Price RE, Hazle JD. MR thermometry-based feedback control of laser interstitial thermal therapy at 980 nm. Lasers in surgery and medicine. 2004;34(1):48-55.29. Jethwa PR, Barrese JC, Gowda A, Shetty A, Danish SF. Magnetic resonance thermometry-guided laser-induced thermal therapy for intracranial neoplasms: initial experience. Neurosurgery. Sep 2012;71(1 Suppl Operative):133-144; 144-135.30. Curry DJ, Gowda A, McNichols RJ, Wilfong AA. MR-guided stereotactic laser ablation of epileptogenic foci in children. Epilepsy & behavior : E&B. Aug 2012;24(4):408-414. 31. Hawasli AH, Bagade S, Shimony JS, Miller-Thomas M, Leuthardt EC. Magnetic resonance imaging-guided focused laser interstitial thermal therapy for intracranial lesions: single-institution series. Neurosurgery. Dec 2013;73(6):1007-1017