Endoscopic epilepsy surgery: Emergence of a new procedure.
BACKGROUND
The use of minimally invasive endoscopic surgery is fast emerging in many subspecialties of neurosurgery as an effective alternative to the open procedures.


OBJECTIVE
The author describe a novel technique of using an endoscope for performing a corpus callosotomy and hemispherotomy. A description of endoscopic disconnection for a hypothalamic hamartoma (HH) and a review of the literature is also presented.


MATERIALS AND METHODS
Thirty four patients underwent endoscopic procedures between January 2010 and March 2015. These included endoscopic-assisted inter-hemispheric trans-callosal hemispherotomy (EH; n = 11), endoscopic-assisted corpus callosotomy with anterior/posterior commissurotomy (CCWC; n = 16), and endoscopic disconnection for HH (n = 7). EH and CCWC were performed with the use of a small craniotomy (4 cm × 3 cm). The surgeries were performed using a rigid high-definition endoscope, bayonetted self-irrigating bipolar forceps, and other standard endoscopic instruments along with the guidance of intra-operative magnetic resonance imaging and neuronavigation. HH disconnection was performed using endoscopic neuronavigation through a burr hole.


RESULTS
Hemispherotomy: Sequelae of middle cerebral artery infarct (5), Rasmussen's syndrome (3), and hemimegalencephaly (3).


OUTCOME
Class I Engel (9) and class II (2), mean follow-up of 8.4 months, range: 3-18 months. Mean blood loss: 85 cc, mean operating time: 210 min. CCWC: All had a diagnosis of Lennox-Gastaut syndrome (LGS), with etiologies of hypoxic insult (10), lissencephaly (2), bilateral band heterotropia (2), microgyria and pachygyria (2). Mean follow-up: 18 ± 4.7 (16-27 months). Drop attacks stopped in all the patients. Seizure frequency and duration decreased >90% (11) and >50% (5). HH: Type II (2), Type III (2), Type IV (3). 5 had IA outcome.


CONCLUSION
The article emphasizes the role of endoscopic procedures for epilepsy surgery and provides a review of literature. This experience may subserve to coin the term "endoscopic epilepsy surgery" for a fast emerging subspeciality in the field of epilepsy surgery.