Patient JA: Surgery for temporal lobe epilepsy

Andrew Venteicher

Visiting sub-intern

Stanford University

July 2010

Patient JA

ID/CC: 24yo right-handed F with medically refractory epilepsy

HPI: 2001: right temporal craniotomy for partial resection of epidermoid cyst of CP

angle2001 – 2010:• first seizure was on POD 0• on medication, she has weekly episodes of strange noise and taste in

her mouth followed by LOC, vocalizations, repetitive oral movements, and convulsive activity.

• incomplete seizure control on trials of oxcarbazepine, lamotrigene.• embarrassing post-ictal behavior, afraid to leave her house.• on disability for epilepsy.

Patient JA (cont)

PMH/PSH: C-section 2004Allergies: phenytoinOutpatient meds: topiramate 200mg BID, levetiracetam 1000mg BIDFH: No history of CNS tumors, seizure disorder.SH: Seven-month old daughter. Daily marijuana, no other drug use.ROS: Poor memory, depressed mood.

Exam: Memory: 2/3 at five minutesUnable to perform simple arithmetic (may be secondary to effort)

Otherwise neurologically intact (CN, motor, sensory, cerebellar, reflexes)

Pre-op MRI: Axial

T2

• T2 hyperintensity of right inferior and middle temporal gyri, correlated well with epileptiform discharges on EEG/MEG

• Progression of incompletely resected epidermoidof right cerebellopontine angle, relative to MRIs at outside hospital

Pre-op MRI: Coronal

FLAIR

• Hyperintensity on FLAIR of right inferior temporal lobe

• Non-enhancing right pontine lesion

T1 post-gad

Operative plan

1. Resection for epileptic focus:

Right anterior temporal lobectomy

2. Microscopic dissection of epidermoid

1. Resection of epileptic focusNeocortical structures• Corticoectomy of middle temporal gyrus

• Extended inferiorly to middle fossa floor

• Extended anteriorly to temporal tip

• Removed anterior 2cm of superior temporal lobe

Mesiotemporal structures• Entered temporal horn of lateral ventricle to access hippocampus

• Interoperative corticography: eight-lead electrode recorded frequent spikes from anterior hippocampus

• Anterior hippocampus and amygdala resected

• Entered medial pia to access ambient cistern

Netter

Dr. Nahed/Dr. Eskandar

2a. Initial resection of epidermoid

• Approach through medial aspect of temporal lobe

• Gross: encountered pearly white mass

• Path: stratified squamous epithelium, keratin, cholesterol

• Rad: T1 dark, T2 bright, typically no enhancement

A P

Dr. Nahed/Dr. Eskandar

2b. Dissection to anterior pons

• Approach through medial aspect of temporal lobe

• Gross: encountered pearly white mass

• Path: stratified squamous epithelium, keratin, cholesterol

• Rad: T1 dark, T2 bright, typically no enhancement

A P

Dr. Nahed/Dr. Eskandar

2c. Resection of tumor off basilar artery

• Approach through medial aspect of temporal lobe

• Gross: encountered pearly white mass

• Path: stratified squamous epithelium, keratin, cholesterol

• Rad: T1 dark, T2 bright, typically no enhancement

A PA P

Dr. Nahed/Dr. Eskandar

Post-operative course

• Maintained on home doses of topiramate and levetiracetam• Interval development of superior quadrantanopsia

Pre-op Post-op

Temporal lobe epilepsy

1. Background2. Choosing a surgical approach

Background: Temporal lobe epilepsy

• 20-40% of epilepsy patients have medically refractory epilepsy(400,000 patients in the U.S.)

• Etiologies:1. Mesial temporal sclerosis2. Infections: Systemic, CNS3. Vascular: AVMs, cavernomas4. Neoplasia5. Congenital: cortical dysplasias6. Traumatic: TBI, post-operative7. Genetics

• Familial lateral temporal lobe epilepsy with auditory features (AD)

• Familial mesial temporal lobe epilepsy (usually AD)• Indications for surgery: medically refractory, negatively

impacts patient’s quality of lifeUp To Date 2010.

Background: Surgery for temporal lobe epilepsy

Wiebe et al. NEJM 2001.

- 80 patients randomized- median of 5 seizures/month- complications: 55% surgical

group developed VF defect (rare memory deficit, infarct, infection)

Choosing the surgical approach

Outcomes:Seizure frequencyNeuropsychological outcomes

Approaches:Anterior temporal lobectomyATL with sparing of superior temporal gyrusSelective amygdalo-hippocampectomy

Controversial:Variety of approachesLack of randomized trials

Schramm. Epilepsia 2008.

Three RCTs of surgical approaches:1. ATL with partial or full hippocampectomy

Wyler et al. Neurosurgery 1995.

Patients: 70.

Subjects: age 18-40 , complex partial seizures, originate from medial temporal lobe (EEG), IQ > 69, no foreign lesions

Operation: ATL of 4.5cm (superior, middle, and inferior), with either partial or full hippocampectomy

Results: - At one year, 69% (total) versus 38% (partial) were seizure-free after surgery- At 6 months, no difference in several memory tests

Three RCTs of surgical approaches:2. Left ATL +/- sparing of superior temporal gyrus

Hermann et al. Epilepsia 1999.

Patients: 28.

Subjects: complex partial seizures, originate from left temporal lobe (EEG), left dominant (WADA), IQ > 69,no foreign lesions

Operation: ATL of 4-4.5cm of middle/inferior temporal lobe +/- STG, with full hippocampectomy

Results: - At 6-8 months, no difference in proportion seizure-free (60% vs 55%)- At 6-8 months, no difference in change in visual naming ability

Three RCTs of surgical approaches:3. Transsylvian vs transcortical approach for SAH

Lutz et al. Epilepsia 2004.

Patients: 80.

Subjects: diagnosis of hippocampal sclerosis, age > 16, IQ > 69, not left-handed

Operation: transsylvian – pterional crani then through lateral ventricle

transcortical – crani centered on MTG

Results: - Variety of tests: memory, attention, and executive function- 73% vs 77% were seizure -free at 7 months (NS)- word fluency improved only in pts with transcortical approach (no other differences in many other tests)

Transsylvian - UC Irvine website

Three RCTs of surgical approaches

Wyler Neurosurgery 70 ATL + full or 69% vs 38% seizure-free at 1 yr1995 partial hippocampect. No difference in memory

First author Journal / Year Pts Operation Outcomes

Hermann Epilepsia 30 Left ATL 60% vs 55% seizure-free (N.S.)1999 + / - STG resection No change in naming

Lutz Epilepsia 80 transcortical vs 75% seizure-free at 7 months2004 transsylvian AH (no difference)

Slight difference in neuropsych

• Tailor to experience of surgeon/institution• Tailor to patient’s pre-op localization studies• More RCTs may be helpful, incorporating

QOL/neuropsychologic outcomes

Thank you

Pre-operative planningMesial temporal lobe epilepsy (MTLE)

Up To Date 2010.Berg. Curr Op Neurol 2008.Bender. J Neurosurg 2009.

• Most common indication for epilepsy surgery• “Mesial auras” – rising epigastrium, olfactory/gustatory, and fear • MRI: volume loss and T2/FLAIR hyperintensity in hippocampus

Neocortical temporal lobe epilepsy (NTLE)

• Rarer • “Lateral auras” – auditory, visual, somatosensory• Usually structural : post-trauma, tumor, vascular malformation

Pre-op assessment

• Interdisiplinary team• MRI w/ and w/o contrast• EEG, MEG, video-EEG• Neuropsychological testing

“Quest for optimal resection”

Schramm. Epilepsia 2008.

• Controversial

• Few randomized trials

• Variety of methods

Pre-op EEG/MEG

• Left-dominant language center

• Right >> left temporal interictalepileptiform discharges

• Discharges correlate to T2 signal abnormalities in right temporal lobe

Papaniculaou et al. J Neurosurg 1999.