Volumetric image guidance for motor cortex stimulation: integration of three-dimensional cortical anatomy and functional imaging.
OBJECTIVE
Epidural electrical stimulation of the motor cortex is a promising treatment option in patients with intractable pain. Varying rates of success in long-term pain relief have been attributed to inaccurate positioning of the electrode array, partly because the sulcal landmarks are not directly visualized. We describe an integrated protocol for precise electrode placement, combining functional image guidance and intraoperative electrical stimulation in the awake patient.


METHODS
Volumetric rendering of a three-dimensional (3-D) magnetic resonance data set was used to visualize the cortical surface and to superimpose functional magnetic resonance imaging data in six patients with refractory chronic pain. The intraoperative positioning of the quadripolar electrode array was monitored by functional 3-D image guidance. Continuous electrophysiological monitoring and clinical assessment of the motor effects complemented the procedure.


RESULTS
Volumetrically rendered 3-D images were advantageous for the location of the burr hole over the perirolandic area by revealing individual cortical morphological features (e.g., the hand knob) and function at the same time. The exact position of the electrodes was verified reliably by cortical stimulation. No complications were observed throughout the procedures.


CONCLUSIONS
The combination of 3-D functional neuronavigation, intraoperative electrical stimulation, and continuous motor output monitoring in awake patients provides optimal information for the identification of the appropriate somatotopic area of motor cortex. This combined imaging and stimulation approach for electrode positioning offers a safe and minimal invasive strategy for the treatment of intractable chronic pain in selected patients.
Department of Neurosurgery, International Neuroscience Institute, Hannover, Germany. alireza.gharabaghi@uni-tuebingen.de
Alireza
A
Gharabaghi
Dieter
D
Hellwig
Steffen Klaus
SK
Rosahl
Ramin
R
Shahidi
Christoph
C
Schrader
Hans-Joachim
HJ
Freund
Madjid
M
Samii
D000328:Adult; D000368:Aged; D001931:Brain Mapping / Q000379:methods*; D046690:Deep Brain Stimulation / Q000295:instrumentation / Q000379:methods*; D004567:Electrodes, Implanted; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009044:Motor Cortex / Q000473:pathology / Q000503:physiopathology*; D009437:Neuralgia / Q000175:diagnosis* / Q000628:therapy*; D013813:Therapy, Computer-Assisted / Q000379:methods; D016896:Treatment Outcome