Name:
10.3171/2024.10.FOCVID24111
Description:
10.3171/2024.10.FOCVID24111
Thumbnail URL:
https://cadmoremediastorage.blob.core.windows.net/1b2d2e46-2d2b-4f85-9e36-7ca2e470e70e/thumbnails/1b2d2e46-2d2b-4f85-9e36-7ca2e470e70e.jpeg
Duration:
T00H10M24S
Embed URL:
https://stream.cadmore.media/player/1b2d2e46-2d2b-4f85-9e36-7ca2e470e70e
Content URL:
https://cadmoreoriginalmedia.blob.core.windows.net/1b2d2e46-2d2b-4f85-9e36-7ca2e470e70e/4. 24-111.mp4?sv=2019-02-02&sr=c&sig=N56V%2F1p1FezMyXptGl1lj4bAiLQYdBIleiILhjS7liw%3D&st=2026-04-05T02%3A41%3A21Z&se=2026-04-05T04%3A46%3A21Z&sp=r
Upload Date:
2026-04-05T04:29:56.6646444Z
Transcript:
Language: EN.
Segment:0 .
[STIRRING MUSIC]
SPEAKER: Hexamodal awake brain mapping
SPEAKER: for multilobar resection in a dominant hemisphere cortical malformation with drug- resistant epilepsy. A 21-year-old male presented with seizures of 15 years' duration with two semiologies and three to four episodes per month not controlled on five anticonvulsants. He was right-handed with no focal neurological deficits, and neuropsychology assessment was normal. Video-EEG showed left temporal centric spikes. The MRI showed a large left temporo-parieto-occipital cortical malformation with fMRI showing language and faciobrachial function localized within the lesion.
SPEAKER: DTI and synthetic MRI help to delineate the gray-white matter better. The abnormal cortical architecture was delineated better by a synthetic MRI. This video clip shows that the patient had no focal neurological deficits. Preoperative visual assessment was normal. We planned for an awake multilobar resection with hexamodal mapping considering at-risk language, motor, sensory, visual, and auditory functional areas, and subcortical tracts.
SPEAKER: We also mapped the ictal irritative zone using intraoperative electrocorticography. Here are the language assessment charts and the schematic operation theater layout. A scalp block was given and the pin site infiltrated. The patient was positioned supine, neutral with 30 degrees rotation. Scalp EEG electrodes and peripheral neuromonitoring electrodes were placed, followed by polar and suction stimulators were used.
SPEAKER: The hexamodal monitoring parameters are enumerated in this table. The monitored anesthesia care included moderate sedation initially, awake monitoring stage, and finally moderate sedation again. Bispectral index for the depth of sedation. Plug stimulator used for AEP. The incision was planned using neuronavigation guidance.
SPEAKER: Baseline VEP obtained. A left fronto-temporo-parietal craniotomy was done, and the dura was opened based on the superior sagittal sinus. Electrocorticography recordings were obtained from the surface using a 20-contact grid, and the spiking zones were mapped. SSEP phase reversal technique was done to identify the central sulcus. No afterdischarges were noted after cortical stimulation in the 20-contact grid.
SPEAKER: Motor and sensory mapping was then done using bipolar stimulation, starting with 1 milliampere and gradually increased up to 8 milliamperes. Mapping of the hand, face, and lip area was done with serial increase in current intensity. ECoG was also simultaneously looked for any afterdischarges. A positive mapping was obtained in the hand area at 8 milliamps and noticed in the form of a clinical twitch and EMG-positive responses.
SPEAKER: Next, we attempted to map the face area, and we got a negative mapping as per the protocols. The leg area mapping was also negative despite increasing the current as per protocol. After negative mapping of the face and the lip, language mapping was then done. This was done in the patient's native Indian language, Malayalam.
SPEAKER: This is the schema of the hexamodal mapping. [VIDEO PLAYBACK] [SPEAKING MALAYALAM]
SPEAKER: The pia arachnoid was dissected open in the superior parietal lobule to begin the resection. Resection was begun in the least functional areas that were negatively mapped in the superior parietal lobule. Piecemeal resection using suction and CUSA was done. Intervascular subpial resection protecting the prominent vein of Trolard was the mainstay of the piecemeal resection. Language assessment included naming, oral comprehension, repetition, semantic and phonemic fluency, and reading words, phrases, and numbers.
SPEAKER: [SPEAKING MALAYALAM]
SPEAKER: Monopolar suction stimulator was used for subcortical mapping of the arcuate fibers. A bipolar probe was then next used for stimulation and mapping of the postcentral gyrus. The negatively mapped areas were subpially resected in a piecemeal manner. Subcortical motor mapping was done using a suction stimulator, and subpial resection was gently done. Underneath the vein of Trolard, a rim of parenchyma was left for support.
SPEAKER: Subcortical mapping was negative in the deep subcortical white matter. The negative mapping helped us to do a more aggressive resection in the anatomical postcentral gyrus. As the resection extended into the supramarginal, angular gyrus, we restarted the language mapping. [SPEAKING MALAYALAM]
SPEAKER: Subcortical mapping was further continued using the suction stimulator, and gentle subpial intervascular resection was done preserving the vein of Trolard. The resection of the large cortical malformation was extended further gyrus by gyrus after negative cortical mapping and subcortical negative mapping.
SPEAKER: Further piecemeal resection of the postcentral gyrus was done, preserving a bridge of tissue under the vein of Trolard.
SPEAKER: As the resection proceeded into the supramarginal and angular gyrus, the language mapping was restarted. [SPEAKING MALAYALAM]
SPEAKER: Postresection ECoG showed persistent spikes only in the posterior temporal cortex, and further tailored resection was done. However, it was limited due to speech repetition being affected during language mapping. Mild hand weakness during motor mapping resection also precluded further additional resection in the motor cortex. [SPEAKING MALAYALAM]
SPEAKER: After the additional tailored resection, the ECoG showed reduction of spikes and hemostasis was achieved. The AEP and the VEP also showed no postoperative changes. Bone flap was replaced, and the wound was closed in layers. The patient recovered well with an Engel class I outcome and mild right hemiparesis. The postoperative MRI showed a near-total excision of the lesion with a good visual profile.
SPEAKER: Histology showed a type IIB dysplasia.
SPEAKER: And this is a schematic view of the resection cavity with reference to the white matter tracts. Multimodality brain mapping helps to accurately delineate the functional shifts and offer extended safe resections, thus balancing functional preservation versus adequacy of resection. To conclude, multimodality mapping of functional areas guides resection of multilobar eloquent epileptogenic lesions while preserving optimal function and extirpating epileptogenic zones and networks.
SPEAKER: Thank you.
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