UCSD Neurosurgery Sub-Intern Presentations Simon 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

preoperativeintraoperative Surgical planning - options  fMRI  Magnetoencephalography  PET  Transcranial magnetic stimulation  Awake craniotomy  Electrocorticography  SSEP  MEP

preoperativeintraoperative 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)

MEGfMRI 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

MEGEEG 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

transfalcine transcortical 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