Disconnecting Surgical Treatment of Hypothalamic Hamartoma in Children and Adults With Refractory Epilepsy and Proposal of a New Classification.

Abstract

Hypothalamic hamartoma associated with intractable epilepsy is a major problem when surgical management is discussed. Professor Olivier Delalande is Chief Neurosurgeon of the Department of Pediatric Neurosurgery, Fondation Ophtalmologique Adolf de Rothschild, in Paris, France. In recent international symposia, he has reported a series of hypothalamic hamartoma in children and adults with refractory epilepsy, managed with various surgical techniques according to his new classification of hypothalamic hamartomas. With the permission of Professor Akira Yamaura, Chief Editor of the Neurologia medico-chirurgica, this stimulating paper has appeared in this issue. The strategies of his surgery using surgical excision, surgical disconnection or endoscopic disconnection are challenging but safe. His surgical outcomes are that 8 patients are seizure free, one patient has only brief gelastic seizures and 8 patients are dramatically improved. I hope that the authors will have the opportunity to again examine the outcomes in their series several years from now.Tatsuya TANAKA, M.D., D.M.Sc., President of the 30th Annual Meeting of the Japan Society for Pediatric Neurosurgery. AbstractA series of 17 patients aged from 9 months to 32 years with refractory epilepsy due to hypothalamic hamartoma were treated by total removal (one case) and disconnection (16 cases) between 1997 and 2002. The mean age at seizure onset was 16 months. Sixteen patients had gelastic seizures, 14 had partial seizures and three had generalized tonic-clonic seizures. The mean seizure frequency was 21 per day. Four patients had borderline intelligence quotient and the others were mentally retarded. Five patients presented with precocious puberty, one with acromegaly, and four suffered from obesity. Brain magnetic resonance imaging, performed at least twice in each patient, showed the hamartoma as a stable homogeneous interpeduncular mass implanted either on the mammilary tubercle or on the wall of the third ventricle with variable extension to the bottom. Ictal single photon emission computed tomography, performed in four patients, showed hyperperfusion within the hamartoma in two patients. Twenty-five operations were performed in the 17 patients. The first patient underwent total removal of the hamartoma, whereas the following 16 patients underwent disconnection through open surgery (14 procedures) and/or endoscopy (9 procedures). Eight patients became seizure-free, one patient had only brief gelastic seizures, and eight patients were dramatically improved with a mean follow up of 18.6 months (8 days to 43 months). Surgery was safe in all but two patients: the first patient had transient hemiplegia and the third cranial nerve paresis, and the other developed hemiplegia due to ischemia of the middle cerebral artery territory. The quality of life, and behavior and school performance were greatly improved in most patients. Our series illustrates the feasibility and relative safety of disconnection surgery for hypothalamic hamartomas with seizure relief in 5...

Hemispherotomy and other disconnective techniques

“…25,26,40,50,52 The feasibility of the disconnection depends on the plane of insertion. The Delalande classification consists of 4 lesion types: Type 1 has a horizontal implantation plane and may be lateralized on one side; Type 2 has a vertical insertion plane and intraventricular location; Type 3 is a combination of Types 1 and 2; and Type 4 includes all giant hamartomas 19 (Fig. 5).…”

Radiosurgery for hypothalamic hamartomas

“…The hypothesis of an intrinsic epileptogenesis of HH gained impetus after the stereo-EEG demonstration of ictal onsets originating from the hypothalamic lesion, 32 and was further corroborated by subsequent reports showing production of typical gelastic seizures by depth electrode stimulation, ictal SPECT studies demonstrating HH hyperperfusion, and interictal spike source analysis. 4,9,11,12,16,21,22,26,35,45 The epileptogenic activity of HHs has been recently demonstrated at the cellular level: detailed electrophysiological analysis of slices taken from surgical specimens showed the predominance of small GABAergic inhibitory neurons exhibiting an intrinsic "pacemaker-like" behavior. 54 The concept that surgical intervention should mainly target the HH was not easy to accept.…”

“…13,15,35 This also reflects the hesitancy of neurosurgeons to operate on a diencephalic lesion stemming from the hypothalamus, which requires a complex procedure followed by a difficult postoperative period in which multiple vascular and metabolic complications (such as diabetes insipidus, SIADH [syndrome of inappropriate antidiuretic hormone], hyperthermia, hyperphagia, and hypothyroidism) may arise. 9,13,24,35,37,44,45 Substantial seizure improvement following resection, disconnection, or ablation is further proof of the intrinsic epileptogenesis of HHs and the need for a direct approach to produce seizure relief. [2][3][4]8,9,[12][13][14][16][17][18]24,25,28,35,36,[44][45][46][47][48]51,52 The degree of seizure control is linked to the extent of the surgical intervention.…”

“…Other approaches allowing partial or total resection or disconnection include the subfrontal translamina terminalis, the pterional transsylvian, and the subtemporal. 9,35,37 Endoscopic disconnection can be performed as well. 8 Radiofrequency ablation has also been described.…”

Management of hypothalamic hamartomas: progress due to alignment of the stars

“…3,13 The idea that these lesions can be managed using the quicker and somewhat safer option of endoscopic removal was suggested to me by Dr. Jung Uhn Choi at a neuroendoscopy meeting in Naples in 2003. Although I do not use this approach exclusively, I have found that most HHs within the third ventricle are excellent candidates for this type of excision.…”