Visual and sensorimotor cortices mapping during awake resection of lesion on the right periatrium: a case report on brainwaves and their peculiar patterns

Abstract

AbstractAdvances in neurosurgery have allowed for more sophisticated mapping of various eloquent neural structures including the visual cortex. Applications of various modalities of new technologies allow accurate brain mapping for neurosurgical planning and preservation of functions in patients with lesions involving the eloquent cortex. The authors demonstrate the use of various new technologies for accurate presurgical planning, preservation of brain functions, and depiction of patterns of cortical brainwaves, which relate to motor networks and continuous visual stimuli.A patient with a right periatrial lesion involving the optic radiation with no visual field deficits was operated under an awake state and under continuous contralateral electrocorticography and visual monitoring. Presurgically, extra-operative brain mapping for visual-, sensory-, and motor-evoked magnetic fields were completed using magnetoencephalography (MEG). The dipole areas were identified, and the images were fused with a 116-region cortical brain atlas. The ideal trajectory was planned based on these images and diffusion tensor imaging (tractography). The trans-sulcal approachA good agreement for eloquent areas was identified based on extra-operative MEG and intra-operative neurostimulation mappings. The patient had no new neurological or visual-field deficits after the surgery. Certain patterns of brainwaves for motor cortex and visual stimulation were obtained: (a) spikes at the contralateral sensorimotor area when the motor strip was stimulated and (b) up-down and dense-loose continuous visual-evoked brainwaves at the occipital pole toward flashing checkerboard visual stimulation.A combination of extra- and intra-operative brain mappings should ideally be done in patients harboring lesions near eloquent areas. The continuous visual-evoked potential monitoring, using a grid electrode and flashing checkerboard and contralateral sensorimotor responses, observed in our case is interesting and needs further studies.