Biopsy of Brain Stem Glioma Using Motor-Evoked Potential Mapping by Direct Peduncular Stimulation and Individual Adjuvant Therapy-Case Report-

Abstract

A 23-year-old man presented with a brain stem glioma manifesting as a 6-month history of right hemiparesis and diplopia. Serial magnetic resonance imaging showed an intrinsic diffuse brain stem glioma that gradually localized to the left cerebral peduncle after initial adjuvant therapy. Surgery was performed through a left subtemporal transtentorial approach under motor-evoked potential (MEP) mapping by direct peduncular stimulation. The lateral aspect of the midbrain was exposed, a train of five bipolar 25 mA pulses was applied, and MEPs recorded from the extremities. MEPs were only recorded from the left extremities even with left cerebral peduncular stimulation. Partial resection of the tumor was safely performed, with slight temporary neurological worsening. The histological diagnosis was anaplastic astrocytoma. Individual adjuvant therapy based on the results of real-time reverse transcription-polymerase chain reaction of O 6 -methylguanine-deoxyribonucleic acid methyltransferase achieved an almost complete tumor response. Surgery under pyramidal tract mapping and intensive postoperative adjuvant therapy resulted in a good outcome despite the presence of a generally intractable intrinsic brain stem glioma.

Adult Brainstem Gliomas

“…The resection of diffuse intrinsic brainstem gliomas is impossible, and a surgical approach is justified only in the case of shunt placement for symptomatic relief [29,30]. It is often considered that adult patients exhibiting the classic radiological picture of a diffusely infiltrating nonenhancing lesion, which enlarges the brainstem, do not require a biopsy because of a perceived unfavorable risk/benefit ratio of a biopsy [4].…”

“…Surgical resection is recommended in some cases including dorsal exophytic tumors protruding into the fourth ventricle. Improvement in neurosurgical techniques (particularly the use of intraoperative ultrasound, intraoperative neurophysiological mapping, and computer reconstruction techniques) has facilitated partial resection of tumors previously considered inoperable, or even gross total removal in some cases, without affecting the functional status [30]. A stereotaxic approach can be a rapid and safe method for evacuation of the contents of cysts, providing a neurological benefit in most cases [29].…”

Motor evoked potential mapping and monitoring by direct brainstem stimulation

“…Biopsy sampling of brainstem glioma tissue using MEP mapping by direct peduncular stimulation has been de- scribed elsewhere. 17 Surgery was performed via a left subtemporal transtentorial approach under MEP mapping by direct peduncular stimulation. The lateral aspect of the midbrain was exposed, and a train of five bipolar, 25 mA pulses was applied and MEPs recorded from the extremities.…”

Gliomas de tallo cerebral; generalidades de diagnóstico, tratamiento y pronóstico

“…La resección de GTCID sigue siendo un reto por el hecho de las secuelas neurológicas que pueden generarse y la mínima cantidad de resección que se obtiene, un abordaje quirúrgico sólo está justificado en el caso de la colocación de una derivación para el alivio de síntomas. 27,28 En la práctica, el papel de la cirugía se limita a la biopsia cuya indicación sigue siendo controvertida. Un estudio prospectivo incluyó 46 pacientes adultos con lesiones de tallo cerebral comparado con el diagnóstico preoperatorio evaluado por la IRM convencional contra el resultado histológico obtenido por biopsia estereotáctica.…”