Anterior temporal lobectomy for epilepsy: success and shortcomings

Dario J. Englot, visiting student

Yale MD/PhD ProgramSeptember 24, 2009

Department of Neurosurgery

Department of Neurosurgery

61-year-old right-handed male with seizures for past 20 years per pt: daily “day dreaming” spells, losing touch with reality per wife: during seizures, face droops, clears throat, says

“okay” repeatedly, non responsive for ~30s no aura; somewhat confused for several minutes afterwards has failed management with multiple anti-epileptics:

depakote, carbamazepine, lamotrigine, levetiracetam

PMH/PSH: retinal and shoulder surgeries Meds: levetiracetam, ASA, MVI NKDA SH: married engineer, no substance abuse FH: no epilepsy

Patient history

All vital signs in normal limits, and normal cardiopulmonary exam

Neurological exam: no deficits detected in mental status, cranial nerves, strength, sensation, reflexes, cerebellar function, or gait

Scalp EEG monitoring shows clinical episodes are associated with left temporal seizure activity

MRI, PET (outside hospital)

Physical exam and tests

MRI

MRI

PET

Left anterior temporal lobectomy Dr. Emad Eskandar Assist: Dr. Jason Gerrard

Post-operatively expressive aphasia for a few hours urinary retention: treated full, uneventful recovery afterwards

Operative course

Post-Op MRI

Blumenfeld (2002) Neuroanatomy

Hippocampal sclerosis: in 50-70% of resected hippocampi DeLanerolle (2003) Epilepsia

Eid et al (2007) Acta Neuropathol

Hippocampus in mesial temporal lobe epilepsy (MTLE)

Medically refractory seizures with diminished QOL? History, neurology consultations, and neuropsychology

reports Localizable lesion or seizure focus?

Scalp or intracranial electrode EEG (ictal, interictal) MRI (interictal) PET (interictal) SPECT (ictal, interictal)

Localized seizure focus in a resectable region? fMRI Wada Language mapping Neuropsychological evaluation

MTLE: Who should have surgery?

Spencer (2002) The Lancet Berg et al (2003) Epilepsia

Spencer and Huh (2008) The Lancet

Temporal LobectomyOutcomes

Identifiable lesions and consistent imaging and electrophysiological findings improve outcomes

Some “good” surgical candidates, including those with unilateral temporal lobe sclerosis, nevertheless have recurrence post-operatively

Pathogenesis: Incomplete resection of epileptogenic lesions vs. new epileptogenicity

Why does surgery sometimes fail?

Extent of resection: anterior lobectomy vs. selective amygdalohippocampectomy Cohort study,100 patients (50 each surgery),

followed 5 yr: no statistical difference in recurrence rates1

Demographics: age, sex, or duration of epilepsy Retrospective chart review, 105 patients,

followed up to 3 yr: no relationship between factors & recurrence2

1) Tanriverdi et al (2008) J Neurosurg 2) Ramos et al (2009) J Neurosurg

Why does surgery sometimes fail?

Pre-op electrophysiology and imaging results Retrospective review, 118 pts, followed 1 yr:

similar data with/without recurrence1 (also found in previously mentioned study2)

Historical risk factors: head trauma, tuberous sclerosis, VP shunts, AVMs, CNS infection, global hypoxia, febrile seizures, status epilepticus 118 patients followed 1 yr: only status epilepticus

showed prediction (p = 0.0276) of a higher recurrence rate1

Why does surgery sometimes fail?

1) Hardey et al (2003) Epilepsia 2) Ramos et al (2009) J Neurosurg

Discontinuation of antiepileptic drugs (AEDs) 6 retrospective clinical studies each with > 5 patients

taken off meds (total N = 54-210 per study) Sironi et al (1983) Riv Neurol; Murro et al (1991) J Epilepsy;

Schiller et al (2000) Neurology; Van Veelan (2001) Ned Tijdschr Geneeskd; Al-Kaylani (2002) Epilepsia; Lachhwani (2003) Neurology

Relapse rate after AEDs D/Ced: 32-36% (f/u 1-6 yr) Relapse rate with AEDs onboard: 7-17% (f/u 1-5

yr) No benefit of waiting to attempt AED D/C after 2

yr in adults and 1 yr childrenReviewed in: Hardey et al (2003) Epilepsia

Why does surgery sometimes fail?

Schmidt (2004) Epilepsia

Seizure-free (%)

Limitation: possible selection bias with retrospective observations

Further study: need randomized, double-blind, placebo-controlled trial of AED continuation vs. discontinuation 2 yr post-op

AED discontinuation after temporal lobectomy

Hardey et al (2003) Epilepsia (review); Sironi et al (1983) Riv Neurol; Murro et al (1991) J Epilepsy; Schiller et al (2000) Neurology; Van Veelan (2001) Ned

Tijdschr Geneeskd; Al-Kaylani (2002) Epilepsia; Lachhwani (2003) Neurology

Medically-refractory mesial TLE can often be treated successfully with temporal lobe resection

Seizure recurrence post-operatively can be difficult to predict, but may be reduced with sustained (> 2 yr) anti-epileptic therapy

To the faculty, residents, and staff of MGH neurosurgery

Conclusions

Thank you