Epilepsy Surgery: Temporal Lobe

Epilepsy CON: Selective Amygdalohippocampectomy

December 4, 2011

Gregory D. Cascino, MD

Mayo Clinic

Rochester, MN

American Epilepsy Society | Annual Meeting

Disclosure

Research – Educational Grants

• Neuro Pace, Inc.

• American Epilepsy Society

• American Academy of Neurology

• Neurology (Associate Editor)

• National Institutes of Health R01NS053998

American Epilepsy Society | Annual Meeting

EPILEPSY epidemiology

• Recurrent, unprovoked events

• Two or more seizures

• Prevalence: 4% (80 years of age)

• Incidence: 180,000 per year

• Early and late onset

• 12.5 billion USD

EPILEPSY efficacy of treatment

• Neurology 2003;60(Suppl 4):S2-12

• About 30-40% will have a difficult

to control seizure disorder

• The 1st and 2nd AEDs are highly

predictive of medical outcome

EPILEPSY

improvement in quality of life

• Related to seizure-free

outcome

• DRIVING

• Education, Employment

• No need for caregiver

• Living independently

EPILEPSY adverse effects

• 25,000-50,000 die of seizures or

related causes each year

• Cognitive disorder

• Depression and Anxiety disorders

• SUDEP (sudden unexplained death in

epilepsy)

• Risk of sudden death is 24 times

controls

INTRACTABLE EPILEPSY treatment strategies

• Curative surgical therapy

– focal cortical resection, reoperation

• Palliative surgery

– VNS, corpus callosotomy

• Antiepileptic drug medication

• Ketogenic or Atkins diet

• Investigational studies

EPILEPSY goals of therapy

• Render patient seizure-free

–No seizures

• Avoid neurological morbidity

–No side effects

• Participating and productive

member of society

–No lifestyle limitations

EPILEPSY SURGERY surgical candidates

• Medically refractory seizures

• Physically, socially disabled

• Localization-related epilepsy

• Low risk for morbidity

• Potential for rehabilitation

EPILEPSY SURGERY

syndromes • Lesional epilepsy: tumor, vascular

anomaly, malformation of cortical

development

• Medial temporal lobe epilepsy:

mesial temporal sclerosis

IMAGING IN EPILEPSY focal cortical dysplasia

• T1-weighted image

• Blurring of the gray-white matter

transition

• Thickening of the gray matter

• Signal change in dysplastic cortex

• Normal examination

Epilepsy & functional anatomy of the

human brain

TEMPORAL LOBECTOMY operative outcome

• Neurology 1998;51:465-71

• Radhakrishnan et al.

(Rochester, MN)

• Excellent outcome: 134 (77%)

• Seizure-free: 120 (69%)

• Operative complication: 2 (1%)

TEMPORAL LOBECTOMY concordant MRI, EEG

• Unilateral hippocampal atrophy

• Unilateral epileptiform discharges

• 94% achieve an excellent outcome

EPILEPSY SURGERY long-term outcome

• Lancet 2011; 378:1388-95

• UCL Institute of Neurology

• 615 adult patients

• Median follow-up 8 years (1-19)

• 497 ATL lobectomies

EPILEPSY SURGERY seizure-free outcome

• 5 years: 52%

• 10 years: 47%

• Unfavorable: extratemporal

EPILEPSY SURGERY comparative study

• NEJM 2001;5:311-318

• Randomized controlled study

• 80 pts with TLE

• London, ON, Canada

• Surgery effective (p< 0.001)

• QOL favors surgery (p< 0.001)

EPILEPSY SURGERY Practice Parameter

• Epilepsia 2003;44:741-751

• Engel et al.

• Temporal lobe and localized

neocortical resections

• ATL

• Single Class I and 24 Class IV

studies showing efficacy

WHY SELECTIVE

AMYGDALOHIPPOCAMPECTOMY

• Reduction in operative

morbidity

–Visual field impairment

–Cognitive deficits

• “Unique” operative technique

SELECTIVE

AMYGADOLHIPPOCAMECTOMY Not candidates ??

• Normal MRI (no MTS)

• Neocortical-subcortical lesion

• Dual pathology

• Mesial temporal lesional pathology

• Significant cognitive impairment

• Non-dominant temporal lobe

epilepsy

COMPARATIVE SEIZURE

OUTCOME

• Eur J Neuro 2007;14:90-4

• Bate et al. (Bristol)

• SAH vs ATL

• 114 patients

• Seizure outcome favored ATL

(p< 0.03)

COMPARATIVE MEMORY

OUTCOME

• Epilepsy & Behavior 2006;9:95-100

• Morino et al. (Osaka)

• SAH (n=32) and ATL (n=17)

• ATL decline in verbal and

nonverbal memory

• SAH slight decline in verbal

memory

COMPARATIVE MEMORY

OUTCOME • Neuropsychologia 1997;35:963-73

• Jones-Gotman et al. (Dublin,

Montreal and Zurich)

• 71 patients

• Neocorticectomy- SAH- ATL

• Learning and recall impaired (left)

• Disconnection produces similar

memory deficits

COMPARATIVE MEMORY

OUTCOME

• J Neurosurg 2010;113:1164-75

• Tanriverdi et al. (Montreal)

• 256 patients (SAH and ATL)

• Seizure outcome was similar

• Memory decline in both

operative groups

• Individualize treatment

Is SAH really Selective?

• Epilepsia 2001;42:731-40

• Dupont et al. (Orsay)

• Volumetric MRI and PET

(before and after SAH)

• 9 patients with MTS

• Significant postoperative

anterior temporal neocortical

hypometabolism

WHY NOT SELECTIVE

AMYGDALOHIPPOCAMPECTOMY • Not proven more efficacious than

standard procedure

• Not proven comparative reduction

in morbidity

• May not resect subcortical-

neocortical pathology

• Potential subtotal resection of the

epileptogenic zone

"The function of a physician

is to cure a few, help many

and comfort all"

Percival Bailey 1892 - 1973

neurosurgeon, physiologist,

professor, University of Chicago