Patient JA: Surgery for temporal lobe epilepsy

Andrew VenteicherVisiting sub-internStanford 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 epidermoid of 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

lobectomy2. 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 life

Up 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 approachOutcomes:

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 yr 1995 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 months 2004 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 interictal epileptiform discharges

• Discharges correlate to T2 signal abnormalities in right temporal lobe

Papaniculaou et al. J Neurosurg 1999.