Endoscope-assisted hemispherotomy: translation of technique from cadaveric anatomical feasibility study to clinical implementation

Restricted access


Appropriately chosen candidates with medically refractory epilepsy may benefit from hemispheric disconnection. Traditionally, this involves a large surgical exposure with significant associated morbidity. Minimally invasive approaches using endoscopic assistance have been described by only a few centers. Here, the authors report on the feasibility of endoscope-assisted functional hemispherotomy in a cadaver model and its first translation into clinical practice in appropriately selected patients.


Three silicone-injected, formalin-fixed cadaver heads were used to establish the steps of the procedure in the laboratory. The steps of disconnection were performed using standard surgical instruments and a straight endoscope. The technique was then applied in two patients who had been referred for hemispherectomy and had favorable anatomy for an endoscope-assisted approach.


All disconnections were performed in the cadaver model via a 4 × 2–cm paramedian keyhole craniotomy using endoscopic assistance. An additional temporal burr hole approach was marked in case the authors were unable to completely visualize the frontobasal and insular cuts from the paramedian vertical view. Their protocol was subsequently used successfully in two pediatric patients. Full disconnection was verified with postoperative tractography.


Full hemispheric disconnection can be accomplished with minimally invasive endoscope-assisted functional hemispherotomy. The procedure is technically feasible and can be safely applied in patients with favorable anatomy and pathology; it may lead to less surgical morbidity and faster recovery.

Article Information

Correspondence Sandi Lam: Baylor College of Medicine, Texas Children’s Hospital, Houston TX. sklam@texaschildrens.org.

INCLUDE WHEN CITING Published online November 2, 2018; DOI: 10.3171/2018.8.PEDS18349.

Disclosures The authors report no conflict of interest concerning the materials or methods used in this study or the findings specified in this paper.

© AANS, except where prohibited by US copyright law.



  • View in gallery

    Disconnections for functional hemispherotomy. A: Callosotomy and insular disconnection. B: Frontobasal and mesial temporal lobe disconnections. Green lines indicate lines of disconnection. Image created by Katherine Relyea, MS, CMI, and printed with permission from Baylor College of Medicine. Figure is available in color online only.

  • View in gallery

    A: Incision and mini craniotomy (solid red line) compared to the standard incision for open hemispherotomy (dashed red line). Green circle indicates burr hole. Ghosted light green burr hole shows a supplemental access point to the temporal horn through the middle temporal gyrus. B: Supine, fixed patient position for endoscope-assisted procedure. Image created by Katherine Relyea, MS, CMI, and printed with permission from Baylor College of Medicine. Figure is available in color online only.

  • View in gallery

    Positioning and opening in the cadaver head (A) and the patient (B, for left hemispherotomy). Midline and coronal suture marked in the cadaver head (C) for right hemispherotomy and middle temporal gyrus access. Planned incisions (D) for case 1 for right hemispherotomy by external landmarks and neuronavigation. Note the possible temporal incision and full craniotomy incision indicated with marking pen. Midline coronal suture and right craniotomy marked on the cadaver head (E). For left hemispherotomy (F): two burr holes over the sagittal sinus with one lateral burr hole on the coronal suture for a 4-cm-long × 2-cm-wide craniotomy in case 1. Figure is available in color online only.

  • View in gallery

    Endoscopic disconnection of the right hemisphere in a cadaver model (A–D) and intraoperative endoscopic pictures (E–H). A: Parafalcine approach to the corpus callosum. B: Callosotomy at the genu. C: Callosotomy at the splenium with a view of the pineal cistern deep to the arachnoid membrane. D: Atrium of the right lateral ventricle, with the choroid plexus leading into the temporal horn. E: Interhemispheric approach to the corpus callosum. F: Callosotomy at the genu. G: Exposure into the left temporal horn. H: View into the left lateral ventricle with white matter disconnections and associated arachnoid planes. ACA = anterior cerebral artery; CC = corpus callosum; R = right. Figure is available in color online only.

  • View in gallery

    Workflow of endoscope-assisted hemispherotomy. Patient is positioned and the operative field is exposed. Callosotomy is performed to enter the ventricle. The frontobasal disconnection and temporal horn unroofing can proceed in a dynamic order. Finally, a partial hippocampectomy for mesial temporal disconnection is performed. Figure is available in color online only.

  • View in gallery

    Case 1. Preoperative baseline (A) and postoperative (B) tractography images showing full hemispheric disconnection. Figure is available in color online only.

  • View in gallery

    Case 1. Preoperative axial T1-weighted (A) and T2-weighted (B) MR images. Case 2. Preoperative axial T1-weighted (C) and T2-weighted (D) MR images.



Bahuleyan BVogel TWRobinson SCohen AR: Endoscopic total corpus callosotomy: cadaveric demonstration of a new approach. Pediatr Neurosurg 47:4554602011


Bendjilali NNelson JWeinsheimer SSidney SZaroff JGHetts SW: Common variants on 9p21.3 are associated with brain arteriovenous malformations with accompanying arterial aneurysms. J Neurol Neurosurg Psychiatry 85:128012832014


Binder DKSchramm J: Transsylvian functional hemispherectomy. Childs Nerv Syst 22:9609662006


Chandra SPKurwale NSChibber SSBanerji JDwivedi RGarg A: Endoscopic-assisted (through a mini craniotomy) corpus callosotomy combined with anterior, hippocampal, and posterior commissurotomy in Lennox-Gastaut syndrome: a pilot study to establish its safety and efficacy. Neurosurgery 78:7437512016


Chandra SPTripathi M: Endoscopic epilepsy surgery: emergence of a new procedure. Neurol India 63:5715822015


Dandy WE: Removal of right cerebral hemisphere for certain tumours with hemiplegia. JAMA 90:8328251928


Delalande OBulteau CDellatolas GFohlen MJalin CBuret V: Vertical parasagittal hemispherotomy: surgical procedures and clinical long-term outcomes in a population of 83 children. Neurosurgery 60 (2 Suppl 1):ONS19ONS322007


Devlin AMCross JHHarkness WChong WKHarding BVargha-Khadem F: Clinical outcomes of hemispherectomy for epilepsy in childhood and adolescence. Brain 126:5565662003


Falconer MAWilson PJ: Complications related to delayed hemorrhage after hemispherectomy. J Neurosurg 30:4134261969


Griessenauer CJSalam SHendrix PPatel DMTubbs RSBlount JP: Hemispherectomy for treatment of refractory epilepsy in the pediatric age group: a systematic review. J Neurosurg Pediatr 15:34442015


Kiehna ENWidjaja EHolowka SCarter Snead O IIIDrake JWeiss SK: Utility of diffusion tensor imaging studies linked to neuronavigation and other modalities in repeat hemispherotomy for intractable epilepsy. J Neurosurg Pediatr 17:4834902016


Krynauw RA: Infantile hemiplegia treated by removing one cerebral hemisphere. J Neurol Neurosurg Psychiatry 13:2432671950


Kucukyuruk BYagmurlu KTanriover NUzan MRhoton AL Jr: Microsurgical anatomy of the white matter tracts in hemispherotomy. Neurosurgery 10 (Suppl 2):3053242014


Lew SMKoop JIMueller WMMatthews AEMallonee JC: Fifty consecutive hemispherectomies: outcomes, evolution of technique, complications, and lessons learned. Neurosurgery 74:1821952014


Lin YHarris DACurry DJLam S: Trends in outcomes, complications, and hospitalization costs for hemispherectomy in the United States for the years 2000–2009. Epilepsia 56:1391462015


Marras CEGranata TFranzini AFreri EVillani FCasazza M: Hemispherotomy and functional hemispherectomy: indications and outcome. Epilepsy Res 89:1041122010


McKenzie K: The present status of a patient who had the right hemisphere removed. JAMA 111:1681938


Morino MShimizu HOhata KTanaka KHara M: Anatomical analysis of different hemispherotomy procedures based on dissection of cadaveric brains. J Neurosurg 97:4234312002


Nasi DIacoangeli MDi Somma LDobran MDi Rienzo AGladi M: Microsurgical endoscopy-assisted anterior corpus callosotomy for drug-resistant epilepsy in an adult unresponsive to vagus nerve stimulation. Epilepsy Behav Case Rep 5:27302016


Oppenheimer DRGriffith HB: Persistent intracranial bleeding as a complication of hemispherectomy. J Neurol Neurosurg Psychiatry 29:2292401966


Ramantani GKadish NEBrandt AStrobl KStathi AWiegand G: Seizure control and developmental trajectories after hemispherotomy for refractory epilepsy in childhood and adolescence. Epilepsia 54:104610552013


Rasmussen T: Hemispherectomy for seizures revisited. Can J Neurol Sci 10:71781983


Rasmussen T: Postoperative superficial hemosiderosis of the brain, its diagnosis, treatment and prevention. Trans Am Neurol Assoc 98:1331371973


Schramm JBehrens E: Functional hemispherectomy. J Neurosurg 87:8018021997


Schramm JKral TClusmann H: Transsylvian keyhole functional hemispherectomy. Neurosurgery 49:8919012001


Shimizu HMaehara T: Modification of peri-insular hemispherotomy and surgical results. Neurosurgery 47:3673732000


Smyth MDVellimana AKAsano ESood S: Corpus callosotomy—Open and endoscopic surgical techniques. Epilepsia 58 (Suppl 1):73792017


Sood SMarupudi NIAsano EHaridas AHam SD: Endoscopic corpus callosotomy and hemispherotomy. J Neurosurg Pediatr 16:6816862015


Tanriverdi TOlivier APoulin NAndermann FDubeau F: Long-term seizure outcome after corpus callosotomy: a retrospective analysis of 95 patients. J Neurosurg 110:3323422009


van der Kolk NMBoshuisen Kvan Empelen RKoudijs SMStaudt Mvan Rijen PC: Etiology-specific differences in motor function after hemispherectomy. Epilepsy Res 103:2212302013


Villemure JRasmussen T: Functional hemispherectomy: methodology. J Epilepsy 3 Suppl:1771821990


Villemure JGMascott CR: Peri-insular hemispherotomy: surgical principles and anatomy. Neurosurgery 37:9759811995




All Time Past Year Past 30 Days
Abstract Views 48 48 48
Full Text Views 24 24 24
PDF Downloads 37 37 37
EPUB Downloads 0 0 0


Google Scholar