Intraoperative mapping and monitoring of the corticospinal tracts with neurophysiological assessment and 3-dimensional ultrasonography-based navigation

Abstract

Combining elaborate neurophysiological assessment, tractography-based neuronavigation, and updated IOUS images provided accurate localization of the CSTs and enabled the safe resection of tumors approximating these tracts. This is the first attempt to evaluate the distance from the CSTs using the threshold of subcortical monopolar stimulation with real-time IOUS for the correction of brain shift. The linear correlation between the distance to the CSTs and the threshold of subcortical stimulation producing a motor response provides an intraoperative technique to better preserve motor function.

Diffusion tensor imaging tractography and intraoperative neurophysiological monitoring in surgery of intracranial tumors located near the pyramidal tract

“…При маленькой силе тока (1-3 мА) при прямой субкортикальной ЭС только у 23 из 67 пациентов не отмечалось перма-нентных неврологических нарушений в послеопе-рационном периоде, что связано с большим объ-емом резекции у данной категории пациентов [39]. Как известно, сила тока имеет прямую взаимозави-симость с расстоянием, на которое он распростра-няется, с примерным соотношением 1 мм -1 мА («золотое правило» нейрофизиологии) [23,[40][41][42].…”

Functional preoperative and intraoperative mapping and monitoring: increasing safety and efficacy in glioma surgery

“…Although this correlation is still under discussion, the majority of neurosurgeons presume a linear correlation of 1 mA of stimulation equals approximately 1 mm of distance of the stimulation point to the CST. 64,76,78,88 Recently we published our own evaluation of the relation of stimulation distance and stimulation energy. These data revealed that the distance-to-energy relationship is not linear and that stimulation points are closer than assumed from the "1 mA resembles 1 mm" rule.…”

“…76,83,88 Concerning this stimulation setup, Szelényi et al performed a highly cited and crucial study comparing train application with the single-pulse technique as well as bipolar and monopolar stimulation. 111 It was found that the CST is most efficiently identified using a multipulse train technique with a monopolar probe.…”

“…3, 76 For mapping of language function during awake surgery, various protocols have been published. The most commonly used is presented in this review.…”

Intraoperative monopolar mapping during 5-ALA–guided resections of glioblastomas adjacent to motor eloquent areas: evaluation of resection rates and neurological outcome

“…We start with an initial stimulation intensity of 10-15 mA, which corresponds to about 10-15 mm from the CST. 16,27,28,30,38 The instant an MEP is elicited, the surgeon is immediately alerted by the change of the high-pitch negative control sound to a low-pitch alert sound. The stimulation intensity is then reduced in 2-mA steps, allowing the surgeon to continue tumor removal until another low-pitch alert sound indicates that resection is getting closer to the CST.…”