Disclosures: Daniel M. De Simon, MS4, MBA: No financial relationships or conflicts of interest

Case Diagnosis: A 55-year-old woman with left temporal astrocytoma.

Case Description or Program Description: The patient presented with a 24-hour history of word finding difficulty and memory deficits associated with blurred vision. MRI revealed a centrally enhancing cystic lesion in the left temporal lobe, with mass-effect along the left temporal lobe and occipital horn. Due to the proximity of the tumor to the speech center of the brain, she underwent preoperative transcortical mapping by navigational brain stimulation (NBS) prior to resection.

Setting: Acute Inpatient Rehabilitation.

Assessment/Results: Brain mapping was performed by loading prior high-resolution T1 MRI images on the NBS system for neuro-navigated transcranial magnetic stimulation (TMS). Responses to magnetic stimulation were obtained using surface electromyography. The patient was videotaped performing object naming of simple black and white images. A 3D map of the cortical speech area was created for operative planning.

During surgical resection, remnants of tumor were left posteriorly along the superficial surface in an effort to preserve speech function. Intraoperative guidance with precise brain mapping resulted in greater resection of the astrocytoma without typical postoperative complications and speech deficits.

Discussion (relevance): NBS is a non-invasive method for localizing cortical areas of interest. Clinical studies suggest that this results in an increase of gross tumor regression by over 35% and an expansion in surgical indication by 14.8%.

Conclusions: This case demonstrates how brain mapping using NBS can be used to optimally plan surgical resection of tumors that are near critical cortical regions to reduce the risk for post-operative neurological deficits and improve functional outcomes.

Level of Evidence: Level V

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PM&R Meeting Abstracts - https://pmrjabstracts.org/abstract/preoperative-transcortical-mapping-by-navigational-brain-stimulation-in-a-case-of-temporal-astrocytoma/