UCSD NeurosurgerySub-Intern PresentationsSimon Buttrick, MSIV

Mount Sinai School of Medicine

Case 21 year old male admitted 11/11 after assault with head

trauma Past medical history: multiple fractures Social history: EtOH socially, no smoking, lives with girlfriend Family history: meningioma in mother Exam:

AOx3, appropriate PERRL, EOMI, CNII-XII grossly intact Strength 5/5 throughout Sensation intact in all four extremities

Case - continued Levetiracetam started March 2012: Seizure, head trauma RLE weakness CT head showed slight interval increase in blood products

concerning for cavernoma rupture

preoperative intraoperative

Surgical planning - options

fMRI Magnetoencephalography PET Transcranial magnetic

stimulation

Awake craniotomy Electrocorticography SSEP MEP

preoperative intraoperative

Surgical planning - options

fMRI Magnetoencephalography PET Transcranial magnetic

stimulation

Awake craniotomy Electrocorticography SSEP MEP

Magnetoencephalography Current → Magnetic field → Current Need ~ 50,000 neurons to create a

measureable field (10 fT) Field is measured by numerous

detectors Source estimated (inverse problem)

MEG fMRI

MEG vs fMRI

Direct representation of neuronal activity

Better time resolution

More readily available Cheaper Better studied

Stuffleberg, Clinical Magnetoencephalography for Neurosurgery, Neurosurg Clin N Am 22 (2011) 153–167

MEG EEG

MEG vs EEG

Less distortion of signal by scalp

Better spatial resolution

Sensitive to both tangential and radial components of current

Less signal drop off with distance

Median nerve stimulation

Tibial nerve stimulation

Hand motor response

Foot motor response

transfalcinetranscortical

interhemispheric

Anesthetic considerations Risk of air embolism

Central line Continuous precordial doppler Arterial line

Operating near motor and sensory areas MEP SSEP Brain lab

Post-op course POD1:

Moderate right pronator drift RUE: 4+/5 RLE: proximally 5/5, ankle plantarflexion 3/5, ankle dorsiflexion 2/5,

wiggling toes “95%” sensation in R hemibody Ambulating with physical therapy

POD2: discharged home Mild right pronator drift RUE: 5/5 RLE: proximally 5/5, ankle plantarflexion 4/5, ankle dorsiflexion 3/5,

wiggling toes

Recovery No good data on recovery of motor function after

corticectomy in motor strip In stroke patients, initial degree of paresis is strongest

predictor for recovery

Thank you Special thanks to Dr. Khalessi and Jayant

References Stuffleberg, Clinical Magnetoencephalography for Neurosurgery, Neurosurg Clin N Am

22 (2011) 153–167 Gross et al., The natural history of intracranial cavernous malformations, Neurosurg

Focus 30 (6):E24, 2011 Kekhia et al., Special Surgical Considerations for Functional Brain Mapping, Neurosurg

Clin N Am 22 (2011) 111–132 Hendricks et al., Motor Recovery After Stroke: A Systematic Review of the Literature,

Arch Phys Med Rehabil Vol 83, November 2002