epilepsy surgery overview anumeha sharma fellow, clinical neurophysiology - eeg university of...
TRANSCRIPT
![Page 1: Epilepsy Surgery Overview Anumeha Sharma Fellow, clinical neurophysiology - EEG University of Cincinnati Medical Center](https://reader038.vdocument.in/reader038/viewer/2022110321/56649cff5503460f949d1022/html5/thumbnails/1.jpg)
Epilepsy Surgery Overview
Anumeha Sharma
Fellow, clinical neurophysiology - EEG
University of Cincinnati Medical Center
![Page 2: Epilepsy Surgery Overview Anumeha Sharma Fellow, clinical neurophysiology - EEG University of Cincinnati Medical Center](https://reader038.vdocument.in/reader038/viewer/2022110321/56649cff5503460f949d1022/html5/thumbnails/2.jpg)
Case - GT• 36 year old RHM seen in clinic for a 7 year history of
episodes of panic, nausea, déjà vu initially diagnosed as panic attacks. Subsequently additional behaviors of patting, slapping with right hand and confusion, asking strange questions – “When does school start again? What grade am I in?”
• Frequency – Clusters of upto 9 seizures every 2-3 months
• EEG – normal• MRI – normal • Medications tried - Topamax (aggression – NE), Lamictal
- NE)• Current medications – Keppra (depression), Zonisamide
![Page 3: Epilepsy Surgery Overview Anumeha Sharma Fellow, clinical neurophysiology - EEG University of Cincinnati Medical Center](https://reader038.vdocument.in/reader038/viewer/2022110321/56649cff5503460f949d1022/html5/thumbnails/3.jpg)
What would be the next step in management?
A. Start lacosamide
B. Refer for presurgical evaluation
C. Refer for VNS placement
D. Refer to psychiatry
![Page 4: Epilepsy Surgery Overview Anumeha Sharma Fellow, clinical neurophysiology - EEG University of Cincinnati Medical Center](https://reader038.vdocument.in/reader038/viewer/2022110321/56649cff5503460f949d1022/html5/thumbnails/4.jpg)
Prognosis of epilepsy
• Prevalence ~ 0.5% to 1.0% (Hauser, 1998)
• ~ 70 % (35- 82%) have complete control with medications • Generalized - 74- 82%• Focal onset - 35-58% (strokes and vascular
malformations respond better than trauma, CD, MTS, tumors)
• ~ 20 – 40 % have drug resistant* disease
• ~ 4-16% chance of seizure freedom with additional drug trials
![Page 5: Epilepsy Surgery Overview Anumeha Sharma Fellow, clinical neurophysiology - EEG University of Cincinnati Medical Center](https://reader038.vdocument.in/reader038/viewer/2022110321/56649cff5503460f949d1022/html5/thumbnails/5.jpg)
Prognosis of epilepsy over time
Sillanpaa et al NEJM 1998
![Page 6: Epilepsy Surgery Overview Anumeha Sharma Fellow, clinical neurophysiology - EEG University of Cincinnati Medical Center](https://reader038.vdocument.in/reader038/viewer/2022110321/56649cff5503460f949d1022/html5/thumbnails/6.jpg)
Diminishing returns of multiple AED trials
Kwan NEJM 2000;342:314-9NEJM 2Kwan000;342:314-9.
![Page 7: Epilepsy Surgery Overview Anumeha Sharma Fellow, clinical neurophysiology - EEG University of Cincinnati Medical Center](https://reader038.vdocument.in/reader038/viewer/2022110321/56649cff5503460f949d1022/html5/thumbnails/7.jpg)
Pharmacoresistance• Introduction of newer AEDs
• ~ 25-50% responder rate (50% seizure reduction)
• 5% of previously refractory patients become seizure free (French et al 2004)
• ~ 5-10 % discontinue the medications due to adverse effects (Singhvi et al 2000)
• VNS has a very low chance of achieving seizure freedom in MRE• Should not be considered before resective
surgery • Reserved for poor candidates (palliative)
![Page 8: Epilepsy Surgery Overview Anumeha Sharma Fellow, clinical neurophysiology - EEG University of Cincinnati Medical Center](https://reader038.vdocument.in/reader038/viewer/2022110321/56649cff5503460f949d1022/html5/thumbnails/8.jpg)
Pharmacoresistence
• No agreement over the frequency and duration of epilepsy to constitute intractability
• Pharmacoresistance should be established within a few years of starting AED therapy (Berg et al, 2003; Devinsky, 1999)
• Absolute seizure freedom is the only outcome associated with improved quality of life
![Page 9: Epilepsy Surgery Overview Anumeha Sharma Fellow, clinical neurophysiology - EEG University of Cincinnati Medical Center](https://reader038.vdocument.in/reader038/viewer/2022110321/56649cff5503460f949d1022/html5/thumbnails/9.jpg)
Medically Refractory Epilepsy
• ILAE definition - Failure of adequate trials of two tolerated and and appropriately used AED regimens as monotherapy or in combination to achieve seizure freedom
• Treatment failure due to lack of clinical efficacy
• Seizure freedom should be at least 1 year or 3 times the pretreatment seizure free interval
![Page 10: Epilepsy Surgery Overview Anumeha Sharma Fellow, clinical neurophysiology - EEG University of Cincinnati Medical Center](https://reader038.vdocument.in/reader038/viewer/2022110321/56649cff5503460f949d1022/html5/thumbnails/10.jpg)
Predictors of therapy resistance
• Early age at seizure onset
• Tonic or myoclonic seizures
• Symptomatic etiologies
• History of status epilepticus • (Chen et al, 2002; Ko and Holmes,
1999).
![Page 11: Epilepsy Surgery Overview Anumeha Sharma Fellow, clinical neurophysiology - EEG University of Cincinnati Medical Center](https://reader038.vdocument.in/reader038/viewer/2022110321/56649cff5503460f949d1022/html5/thumbnails/11.jpg)
Risks of refractory Epilepsy • Mortality
• SMR 5.1 compared to 1.6 - 2.3 in general epilepsy population
• Successful epilepsy surgery decreases mortality (Sperling et al, 1996)
• Sudden unexpected death in epilepsy (SUDEP) - 0.5% per year, cumulative over lifetime (Sillanpaa et al, 1998)
• Increased seizure frequency• Increasing number of AEDs (ever used)• Early onset of epilepsy• Frequent changes of AEDs• GTCs
Nilsson et al. 1999; Langan et al 2005, Beran et al. 2004,
![Page 12: Epilepsy Surgery Overview Anumeha Sharma Fellow, clinical neurophysiology - EEG University of Cincinnati Medical Center](https://reader038.vdocument.in/reader038/viewer/2022110321/56649cff5503460f949d1022/html5/thumbnails/12.jpg)
Risks of Refractory Epilepsy• Cognitive - Slowly progressive cortical atrophy
and Cognitive decline (Jokeit and Ebner, 1999)
• Psychiatric – Depression• ~1.8x in patients with epilepsy vs. general
population,
• 20-55% in MRE vs. 3-9 % in well controlled epilepsy patients
• High seizure frequency, focal onset seizures, female gender (JJ Barry et al 2008)
• Injury • Quality of life, Driving, School and Employment
![Page 13: Epilepsy Surgery Overview Anumeha Sharma Fellow, clinical neurophysiology - EEG University of Cincinnati Medical Center](https://reader038.vdocument.in/reader038/viewer/2022110321/56649cff5503460f949d1022/html5/thumbnails/13.jpg)
Candidates for surgery
• ~ 50 % of MRE patients are candidates for focal resective surgery
• Rest can be considered for a variety of palliative procedures i.e. VNS, RNS or diets
• Symptomatic focal onset related epilepsy - most likely to receive seizure freedom from surgery
![Page 14: Epilepsy Surgery Overview Anumeha Sharma Fellow, clinical neurophysiology - EEG University of Cincinnati Medical Center](https://reader038.vdocument.in/reader038/viewer/2022110321/56649cff5503460f949d1022/html5/thumbnails/14.jpg)
Temporal lobectomy vs. medication
Wiebe et al, NEJM, 2001
![Page 15: Epilepsy Surgery Overview Anumeha Sharma Fellow, clinical neurophysiology - EEG University of Cincinnati Medical Center](https://reader038.vdocument.in/reader038/viewer/2022110321/56649cff5503460f949d1022/html5/thumbnails/15.jpg)
AAN Practice parameter 2003
• One Class I RCT of surgery for MTLE
• 58% of patients randomized in the surgical arm (64% of those who received surgery) were free of disabling seizures, compared with 8% seizure freedom in the medical arm
• Improvement in quality of life and driving, employment, mortality, some neuropsychological parameters
![Page 16: Epilepsy Surgery Overview Anumeha Sharma Fellow, clinical neurophysiology - EEG University of Cincinnati Medical Center](https://reader038.vdocument.in/reader038/viewer/2022110321/56649cff5503460f949d1022/html5/thumbnails/16.jpg)
AAN practice parameter 2003
• “Patients with disabling complex partial seizures, with or without secondarily generalized seizures, who have failed appropriate trials*of first-line antiepileptic drugs should be considered for referral to an epilepsy surgery center”(Engel et al 2003)
![Page 17: Epilepsy Surgery Overview Anumeha Sharma Fellow, clinical neurophysiology - EEG University of Cincinnati Medical Center](https://reader038.vdocument.in/reader038/viewer/2022110321/56649cff5503460f949d1022/html5/thumbnails/17.jpg)
Surgical outcome - summary
Epilepsy Outcome (seizure free)Temporal lobe lesion ~ 80%
Mesial temporal sclerosis ~ 70%
“Normal” temporal lobe ~ 60%
Lesional extratemporal ~ 60%
Nonlesional extratemporal < 50%
![Page 18: Epilepsy Surgery Overview Anumeha Sharma Fellow, clinical neurophysiology - EEG University of Cincinnati Medical Center](https://reader038.vdocument.in/reader038/viewer/2022110321/56649cff5503460f949d1022/html5/thumbnails/18.jpg)
Morbidity and mortality • Mortality <1%• Morbidity 3-6%
• Infections, hemorrhage, and neurological deficits, ~ transient
• Principal post surgical complication – cognitive • Some decline in verbal or non verbal memory or
language• Transiently worsened anxiety or
depression in 20-40 % (Engel et al 2003)
• In general, overall risk of surgery is lower than risk of refractory epilepsy (Engel et al 2003)
• mortality in RCTS of AEDS ~ 0.78% per year
![Page 19: Epilepsy Surgery Overview Anumeha Sharma Fellow, clinical neurophysiology - EEG University of Cincinnati Medical Center](https://reader038.vdocument.in/reader038/viewer/2022110321/56649cff5503460f949d1022/html5/thumbnails/19.jpg)
Who is not a surgical candidate?
• Clear evidence of more than one focus or bilateral onset
• Progressive disease (multiple sclerosis, cerebral vasculitis, HIV, meningitis, and high-grade malignant brain tumors)
• Diffuse neuropsychological deficits
• Significant psychiatric disease
![Page 20: Epilepsy Surgery Overview Anumeha Sharma Fellow, clinical neurophysiology - EEG University of Cincinnati Medical Center](https://reader038.vdocument.in/reader038/viewer/2022110321/56649cff5503460f949d1022/html5/thumbnails/20.jpg)
Epilepsy Surgery Evaluation - Initial
• History and examination
• Video and (scalp) EEG monitoring
• Structural Imaging – MRI
• Functional Imaging – PET, Ictal and Interictal SPECT
• Tests for functional localization – Wada, Neuropsychometric testing, functional MRI
![Page 21: Epilepsy Surgery Overview Anumeha Sharma Fellow, clinical neurophysiology - EEG University of Cincinnati Medical Center](https://reader038.vdocument.in/reader038/viewer/2022110321/56649cff5503460f949d1022/html5/thumbnails/21.jpg)
Structural Imaging - MRI
• Best available tool for identification of epileptogenic lesions
• Provides information about• Presumptive pathology • Anatomic location
• Coronal T1 and FLAIR with thin cuts – MTS, CD• GRE – cavernoma • Hamartomas, polymicrogyria, neuronal
migration disorders, AVM, low grade tumors
![Page 22: Epilepsy Surgery Overview Anumeha Sharma Fellow, clinical neurophysiology - EEG University of Cincinnati Medical Center](https://reader038.vdocument.in/reader038/viewer/2022110321/56649cff5503460f949d1022/html5/thumbnails/22.jpg)
MRI
• Lesion on MRI may or may not reflect the epileptogenic zone
• The success rates for epilepsy surgeries done on patients with “unremarkable” MRI is much lower
• Use of 3 Tesla magnets has lead to increased number of patients eligible for surgery (knake et al, 2005)
![Page 23: Epilepsy Surgery Overview Anumeha Sharma Fellow, clinical neurophysiology - EEG University of Cincinnati Medical Center](https://reader038.vdocument.in/reader038/viewer/2022110321/56649cff5503460f949d1022/html5/thumbnails/23.jpg)
MRI – GT
![Page 24: Epilepsy Surgery Overview Anumeha Sharma Fellow, clinical neurophysiology - EEG University of Cincinnati Medical Center](https://reader038.vdocument.in/reader038/viewer/2022110321/56649cff5503460f949d1022/html5/thumbnails/24.jpg)
Long term video EEG monitoring
• Both ictal and interictal EEG
• Essential to capture complete sample of typical seizures to clarify region(s) of seizure onset
• Ictal EEG gives valuable lateralizing and localizing information with regard to the seizure focus (Jobst et al, 2001)
• Temporal lobe seizures higher yield than extratemporal 76 – 83 vs 47 – 65%
![Page 25: Epilepsy Surgery Overview Anumeha Sharma Fellow, clinical neurophysiology - EEG University of Cincinnati Medical Center](https://reader038.vdocument.in/reader038/viewer/2022110321/56649cff5503460f949d1022/html5/thumbnails/25.jpg)
![Page 26: Epilepsy Surgery Overview Anumeha Sharma Fellow, clinical neurophysiology - EEG University of Cincinnati Medical Center](https://reader038.vdocument.in/reader038/viewer/2022110321/56649cff5503460f949d1022/html5/thumbnails/26.jpg)
Phase I scalp EEG - GT
![Page 27: Epilepsy Surgery Overview Anumeha Sharma Fellow, clinical neurophysiology - EEG University of Cincinnati Medical Center](https://reader038.vdocument.in/reader038/viewer/2022110321/56649cff5503460f949d1022/html5/thumbnails/27.jpg)
Phase I scalp EEG - GT
![Page 28: Epilepsy Surgery Overview Anumeha Sharma Fellow, clinical neurophysiology - EEG University of Cincinnati Medical Center](https://reader038.vdocument.in/reader038/viewer/2022110321/56649cff5503460f949d1022/html5/thumbnails/28.jpg)
Functional Imaging - PET scan
• Metabolic maps of the brain
• Especially useful in non lesional MRI
• 18F FDG provides measure of interictal regional glucose metabolism
• Decreased metabolism represents functional deficit zone (65 - 90% of TLE patients)
• Unilateral temporal lobe hypometabolism on 18F-FDG-PET strongly predicts seizure freedom with resection of that temporal lobe, independent of MRI findings (Theodore et al 1992)
![Page 29: Epilepsy Surgery Overview Anumeha Sharma Fellow, clinical neurophysiology - EEG University of Cincinnati Medical Center](https://reader038.vdocument.in/reader038/viewer/2022110321/56649cff5503460f949d1022/html5/thumbnails/29.jpg)
PET Scan - GT
• Coronal and axial images
![Page 30: Epilepsy Surgery Overview Anumeha Sharma Fellow, clinical neurophysiology - EEG University of Cincinnati Medical Center](https://reader038.vdocument.in/reader038/viewer/2022110321/56649cff5503460f949d1022/html5/thumbnails/30.jpg)
![Page 31: Epilepsy Surgery Overview Anumeha Sharma Fellow, clinical neurophysiology - EEG University of Cincinnati Medical Center](https://reader038.vdocument.in/reader038/viewer/2022110321/56649cff5503460f949d1022/html5/thumbnails/31.jpg)
![Page 32: Epilepsy Surgery Overview Anumeha Sharma Fellow, clinical neurophysiology - EEG University of Cincinnati Medical Center](https://reader038.vdocument.in/reader038/viewer/2022110321/56649cff5503460f949d1022/html5/thumbnails/32.jpg)
Functional localization
• Eloquent cortices essential for language, memory, motor, or sensory functions must often be delineated
• Resection can be tailored to avoid causing functional deficits. • Neuropsychometric testing • Functional MRI• IAP (Wada) test • Magnetoencephalography
![Page 33: Epilepsy Surgery Overview Anumeha Sharma Fellow, clinical neurophysiology - EEG University of Cincinnati Medical Center](https://reader038.vdocument.in/reader038/viewer/2022110321/56649cff5503460f949d1022/html5/thumbnails/33.jpg)
Neuropsychometric testing
• Quantify, lateralize and localize cognitive deficits
• Predict cognitive decline after epilepsy surgery
• Obtained pre and post operatively to determine if new deficits have developed
• Correlated with seizure foci identified using other techniques
![Page 34: Epilepsy Surgery Overview Anumeha Sharma Fellow, clinical neurophysiology - EEG University of Cincinnati Medical Center](https://reader038.vdocument.in/reader038/viewer/2022110321/56649cff5503460f949d1022/html5/thumbnails/34.jpg)
Wada test
• Functions as the transient mimic of the effects of the proposed surgery
• Amobarbital is injected into the ICA , temporarily disrupting function on that side, while language and memory tests are performed
• The best validated method of determining• Language dominant hemisphere • Assess risk of postoperative memory
deterioration after temporal lobectomy
![Page 35: Epilepsy Surgery Overview Anumeha Sharma Fellow, clinical neurophysiology - EEG University of Cincinnati Medical Center](https://reader038.vdocument.in/reader038/viewer/2022110321/56649cff5503460f949d1022/html5/thumbnails/35.jpg)
Predictors of higher risk of cognitive decline after temporal lobectomy
• Intact baseline cognitive ability
• Dominant temporal lobe resection
• Later age of epilepsy onset
• Normal MRI results
• Female gender
• Loss of memory function during injection of amobarbital into the carotid artery on the side of planned surgery
![Page 36: Epilepsy Surgery Overview Anumeha Sharma Fellow, clinical neurophysiology - EEG University of Cincinnati Medical Center](https://reader038.vdocument.in/reader038/viewer/2022110321/56649cff5503460f949d1022/html5/thumbnails/36.jpg)
Summary of phase 1 evaluation - GT
• MRI – Non lesional
• PET – bilateral hypometabolism, non lateralizing
• Video EEG - 1 clear right and 4 likely left temporal seizures, no post ictal language delay
• Temporal lobe onset, unclear lateralization
![Page 37: Epilepsy Surgery Overview Anumeha Sharma Fellow, clinical neurophysiology - EEG University of Cincinnati Medical Center](https://reader038.vdocument.in/reader038/viewer/2022110321/56649cff5503460f949d1022/html5/thumbnails/37.jpg)
Summary of phase 1 evaluation - GT
• Neuropsychometric testing • Not well localized or lateralized anatomically • Excellent cognitive abilities overall• High risk for cognitive decline post operatively
• Wada test • Left sided language dominance • Slightly decreased memory on the left• No major risk of post-operative amnesia
with surgery on either side
![Page 38: Epilepsy Surgery Overview Anumeha Sharma Fellow, clinical neurophysiology - EEG University of Cincinnati Medical Center](https://reader038.vdocument.in/reader038/viewer/2022110321/56649cff5503460f949d1022/html5/thumbnails/38.jpg)
Phase II (intracranial) evaluation
• Precisely delineate the extent of a epileptogenic zone and its relationship to areas of eloquent functional cortex.
• Determine if right or left onset • 10-20% of temporal lobe, 40%-70%
extratemporal cases• ~75% of implanted patients go on to have
resective surgery.• Complications – minor, 1% to 2% of cases
(Siegel, 2004)
![Page 39: Epilepsy Surgery Overview Anumeha Sharma Fellow, clinical neurophysiology - EEG University of Cincinnati Medical Center](https://reader038.vdocument.in/reader038/viewer/2022110321/56649cff5503460f949d1022/html5/thumbnails/39.jpg)
Depth electrodes• Multiple contact needles
• Provide direct access to deep structures
• Very detailed but focused sampling
• Lower complication rate, implanted through burr holes
• Can be left in place for days and weeks with low risk of infections permitting longer monitoring
![Page 40: Epilepsy Surgery Overview Anumeha Sharma Fellow, clinical neurophysiology - EEG University of Cincinnati Medical Center](https://reader038.vdocument.in/reader038/viewer/2022110321/56649cff5503460f949d1022/html5/thumbnails/40.jpg)
Subdural Electrodes
• Used if seizure focus cannot be located with scalp EEG or other diagnostic tests
• Grids or strips• Placed on brain surface, grids and strips are
placed through craniotomy and burr holes respectively
• More precise recording especially for neocortical seizures
• Cortical mapping for functional areas can occur
• Higher complication rate especially for grids
![Page 41: Epilepsy Surgery Overview Anumeha Sharma Fellow, clinical neurophysiology - EEG University of Cincinnati Medical Center](https://reader038.vdocument.in/reader038/viewer/2022110321/56649cff5503460f949d1022/html5/thumbnails/41.jpg)
Grid and Strip
![Page 42: Epilepsy Surgery Overview Anumeha Sharma Fellow, clinical neurophysiology - EEG University of Cincinnati Medical Center](https://reader038.vdocument.in/reader038/viewer/2022110321/56649cff5503460f949d1022/html5/thumbnails/42.jpg)
Intracranial electrode placement- GT
![Page 43: Epilepsy Surgery Overview Anumeha Sharma Fellow, clinical neurophysiology - EEG University of Cincinnati Medical Center](https://reader038.vdocument.in/reader038/viewer/2022110321/56649cff5503460f949d1022/html5/thumbnails/43.jpg)
Phase II intracranial EEG – GT
![Page 44: Epilepsy Surgery Overview Anumeha Sharma Fellow, clinical neurophysiology - EEG University of Cincinnati Medical Center](https://reader038.vdocument.in/reader038/viewer/2022110321/56649cff5503460f949d1022/html5/thumbnails/44.jpg)
Phase II monitoring – GT
• 4 typical seizures arising from left depth electrode (left mesial temporal region)
• Risk vs. benefits of surgery were discussed
• Patient elected to undergo left anterior temporal lobectomy
• 3 month follow up – No seizures, mild anomia, resolved with steroids.
![Page 45: Epilepsy Surgery Overview Anumeha Sharma Fellow, clinical neurophysiology - EEG University of Cincinnati Medical Center](https://reader038.vdocument.in/reader038/viewer/2022110321/56649cff5503460f949d1022/html5/thumbnails/45.jpg)
Epilepsy surgery Timing and trends in the US
• Time interval between onset of seizures and referral for pre-surgical evaluation – 18- 25 years
• Comparison of referral data for patients with TLE from 1995 to 1998 and 2005 to 2008
• Determine whether AAN practice parameter resulted in a change in referral patterns for surgical evaluation
• No improvement in timing of referral for pre-surgical evaluation
![Page 46: Epilepsy Surgery Overview Anumeha Sharma Fellow, clinical neurophysiology - EEG University of Cincinnati Medical Center](https://reader038.vdocument.in/reader038/viewer/2022110321/56649cff5503460f949d1022/html5/thumbnails/46.jpg)
sharm
• 112,026 hospitalizations for medically refractory focal epilepsy
• 6,653 (5.9%) resective surgeries from 1990 to 2008.
• A trend of increasing hospitalizations over time but overall trend of decreasing surgery rates
![Page 47: Epilepsy Surgery Overview Anumeha Sharma Fellow, clinical neurophysiology - EEG University of Cincinnati Medical Center](https://reader038.vdocument.in/reader038/viewer/2022110321/56649cff5503460f949d1022/html5/thumbnails/47.jpg)
Thank You
• David Ficker, MD
• Mariano Fernandez Ulloa, MD