title: Surgical outcomes in patients with intraoperative Electrocorticography (EcoG) guided epilepsy surgery-experiences of a tertiary care centre in India.
abstract: BACKGROUND
  The Comprehensive Epilepsy Surgery Program was started in 2001 at K.E.M. Hospital, Mumbai with the aim of performing epilepsy surgeries at highly concessional rates. We have started using intraoperative Electrocorticography (EcoG) since 2009 in patients with tumors, Mesial Temporal Sclerosis (MTS) plus and focal cortical dysplasia (FCD). This study highlights our experience with EcoG and it's utility in epilepsy surgery.introduction METHODS: 51 patients with drug resistant epilepsy due to temporal and extra-temporal tumors, MTS plus and FCD underwent pre-surgical evaluation and ECoG guided epilepsy surgery through our program. The surgical procedures employed included intraoperative EcoG guided lesionectomy or a lesionectomy with Anterior Temporal Lobectomy (ATL). Postoperative MRI and EEG were done. Seizure freedom was categorized as per Engel's classification.
  
  
  RESULTS
  At a mean follow up of 33 months (range: 14-69 months), 43 out of 51(84.31%) patients were completely seizure free post-surgery (Engel's Class I). Among the patients who were not seizure free, 3 patients were in Engel's Class II and 5 patients were in Engel's Class III. Presence of a residual lesion on postoperative MRI (p < 0.001), abnormal postoperative EEG (p < 0.001) and persistent spikes on post-resection EcoG (p < 0.05) had a significant statistical association with poor seizure freedom post-surgery.
  
  
  CONCLUSIONS
  The success of epilepsy surgery depends upon accurate localization and complete resection of the epileptogenic tissue, both of which are aided by intraoperative EcoG.Thus, intraoperative EcoG is a useful adjunct in epilepsy surgery to achieve optimal seizure freedom in cases of MTS plus, focal cortical dysplasia and tumors. Even the patients who are not seizure free can achieve worthwhile improvement post surgery.
authors.affiliation: Comprehensive Epilepsy Care Centre, Seth GSMC & KEM Hospital, Parel, Mumbai, 400012, India. Electronic address: ravatsh@yahoo.com.
authors.forename: Sangeeta
authors.initials: S
authors.lastname: Ravat
authors.affiliation: Dept. of Neurology, Comprehensive Epilepsy Care Centre, Seth GSMC & KEM Hospital, Parel, Mumbai, 400012, India. Electronic address: drvivekiyer1984@gmail.com.
authors.forename: Vivek
authors.initials: V
authors.lastname: Iyer
authors.affiliation: Dept. of Neurology, Comprehensive Epilepsy Care Centre, Seth GSMC & KEM Hospital, Parel, Mumbai, 400012, India. Electronic address: keyurpanchal83@yahoo.co.in.
authors.forename: Keyurkumar
authors.initials: K
authors.lastname: Panchal
authors.affiliation: Dept. of Neurosurgery, Comprehensive Epilepsy Care Centre, Seth GSMC & KEM Hospital, Parel, Mumbai, 400012, India. Electronic address: dmuzumdar@hotmail.com.
authors.forename: Dattatraya
authors.initials: D
authors.lastname: Muzumdar
authors.affiliation: Department of Neurosurgery, Seth GSMC & KEM Hospital, Parel, Mumbai, 400012, India. Electronic address: abhidude83@gmail.com.
authors.forename: Abhijit
authors.initials: A
authors.lastname: Kulkarni
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D000069280:Electrocorticography; D004827:Epilepsy / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D062606:Tertiary Care Centers
keywords: Anterior temporal lobectomy (ATL); Focal cortical dysplasia (FCD); Interictal epileptiform discharges (IED's); Intraoperative Electrocorticography (EcoG); Lesionectomy